/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

/*-*************************************
*  Dependencies
***************************************/
#include "../common/allocations.h"  /* ZSTD_customMalloc, ZSTD_customCalloc, ZSTD_customFree */
#include "../common/zstd_deps.h"  /* INT_MAX, ZSTD_memset, ZSTD_memcpy */
#include "../common/mem.h"
#include "../common/error_private.h"
#include "hist.h"           /* HIST_countFast_wksp */
#define FSE_STATIC_LINKING_ONLY   /* FSE_encodeSymbol */
#include "../common/fse.h"
#include "../common/huf.h"
#include "zstd_compress_internal.h"
#include "zstd_compress_sequences.h"
#include "zstd_compress_literals.h"
#include "zstd_fast.h"
#include "zstd_double_fast.h"
#include "zstd_lazy.h"
#include "zstd_opt.h"
#include "zstd_ldm.h"
#include "zstd_compress_superblock.h"
#include  "../common/bits.h"      /* ZSTD_highbit32 */

/* Frame serialization lives in Rust.  Keep its interface scalar so the
 * large, configuration-sensitive CCtx parameter structure stays in C. */
size_t ZSTD_rust_writeFrameHeader(void* dst, size_t dstCapacity,
                                  int noDictIDFlag, int checksumFlag,
                                  int contentSizeFlag, int format,
                                  U32 windowLog, U64 pledgedSrcSize,
                                  U32 dictID);
void ZSTD_rust_writeBlockHeader(void* op, size_t cSize, size_t blockSize,
                                U32 lastBlock);
size_t ZSTD_rust_writeEpilogue(void* dst, size_t dstCapacity, int* stage,
                               int noDictIDFlag, int checksumFlag,
                               int contentSizeFlag, int format, U32 windowLog,
                               U32 checksum);
int ZSTD_rust_updateFrameProgression(unsigned long long* consumedSrcSize,
                                     unsigned long long* producedCSize,
                                     unsigned long long pledgedSrcSizePlusOne,
                                     size_t srcSize, size_t cSize,
                                     size_t fhSize);
size_t ZSTD_rust_setPledgedSrcSize(int streamStage,
                                   unsigned long long pledgedSrcSize,
                                   unsigned long long* pledgedSrcSizePlusOne);
ZSTD_frameProgression ZSTD_rust_frameProgression(U64 consumedSrcSize,
                                                  size_t buffered,
                                                  U64 producedCSize);
size_t ZSTD_rust_resetCCtxForSimpleCompression(void* cctx);
size_t ZSTD_rust_prepareCCtxForSimpleCompression(void* cctx,
                                                 size_t srcSize,
                                                 int compressionLevel);
int ZSTD_rust_compressCCtxStrategy(size_t srcSize, int compressionLevel);
size_t ZSTD_rust_resetCCtxForSimpleCompressionSession(void* cctx);
void ZSTD_rust_markSimpleCompression2Complete(void* cctx);
size_t ZSTD_compress2_c(ZSTD_CCtx* cctx,
                        void* dst, size_t dstCapacity,
                        const void* src, size_t srcSize);
size_t ZSTD_compressStream2_c(ZSTD_CCtx* cctx,
                              ZSTD_outBuffer* output,
                              ZSTD_inBuffer* input,
                              ZSTD_EndDirective endOp);
int ZSTD_rust_simpleCompress2Level(const void* cctx, size_t srcSize);
int ZSTD_rust_simpleCompressStream2Level(const void* cctx, size_t srcSize);
void ZSTD_rust_reduceIndex(U32* hashTable, U32 hashSize,
                           U32* chainTable, U32 chainSize,
                           U32* hashTable3, U32 hashSize3,
                           U32 reducerValue, int preserveChainMark);
void ZSTD_rust_copyCDictTableIntoCCtx(U32* dst, U32 const* src,
                                      size_t tableSize, int tagged);
U64 ZSTD_rust_advanceHashSalt(U64 hashSalt, U64 hashSaltEntropy);
int ZSTD_rust_indexTooCloseToMax(size_t nextSrcBaseOffset);
int ZSTD_rust_dictTooBig(size_t loadedDictSize);

/* The frame-chunk loop is Rust-owned.  Its callbacks keep the private
 * ZSTD_CCtx and match-state layout in C: Rust only drives the block loop and
 * passes this context back to these C-owned state-preparation/dispatch seams. */
typedef void (*ZSTD_rust_frameChunkPrepare_f)(void* context,
                                               const void* src,
                                               size_t blockSize);
typedef size_t (*ZSTD_rust_frameChunkCompress_f)(void* context,
                                                 void* dst,
                                                 size_t dstCapacity,
                                                 const void* src,
                                                 size_t srcSize,
                                                 U32 lastBlock);
typedef void (*ZSTD_rust_frameChunkChecksum_f)(void* state,
                                                const void* src,
                                                size_t srcSize);
typedef struct {
    void* callbackContext;
    void* tmpWorkspace;
    void* checksumState;
    int* isFirstBlock;
    ZSTD_compressionStage_e* stage;
    size_t tmpWkspSize;
    size_t blockSizeMax;
    S64 savings;
    int preBlockSplitterLevel;
    int strategy;
    int useTargetCBlockSize;
    int blockSplitterEnabled;
    int checksumFlag;
    int endingStage;
    ZSTD_rust_frameChunkPrepare_f prepareBlock;
    ZSTD_rust_frameChunkCompress_f compressTarget;
    ZSTD_rust_frameChunkCompress_f compressSplit;
    ZSTD_rust_frameChunkCompress_f compressInternal;
    ZSTD_rust_frameChunkChecksum_f updateChecksum;
} ZSTD_rust_frameChunkState;
size_t ZSTD_rust_compressFrameChunk(
        const ZSTD_rust_frameChunkState* state,
        void* dst, size_t dstCapacity,
        const void* src, size_t srcSize,
        U32 lastFrameChunk);
typedef char ZSTD_rust_frame_chunk_state_layout[
        (offsetof(ZSTD_rust_frameChunkState, callbackContext) == 0
         && offsetof(ZSTD_rust_frameChunkState, tmpWorkspace) == sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, checksumState) == 2 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, isFirstBlock) == 3 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, stage) == 4 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, tmpWkspSize) == 5 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, blockSizeMax) == 6 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, savings) == 7 * sizeof(void*)
         && offsetof(ZSTD_rust_frameChunkState, preBlockSplitterLevel)
                == 7 * sizeof(void*) + sizeof(S64)
         && offsetof(ZSTD_rust_frameChunkState, strategy)
                == 7 * sizeof(void*) + sizeof(S64) + sizeof(int)
         && offsetof(ZSTD_rust_frameChunkState, useTargetCBlockSize)
                == 7 * sizeof(void*) + sizeof(S64) + 2 * sizeof(int)
         && offsetof(ZSTD_rust_frameChunkState, blockSplitterEnabled)
                == 7 * sizeof(void*) + sizeof(S64) + 3 * sizeof(int)
         && offsetof(ZSTD_rust_frameChunkState, checksumFlag)
                == 7 * sizeof(void*) + sizeof(S64) + 4 * sizeof(int)
         && offsetof(ZSTD_rust_frameChunkState, endingStage)
                == 7 * sizeof(void*) + sizeof(S64) + 5 * sizeof(int)
         && offsetof(ZSTD_rust_frameChunkState, prepareBlock)
                == 7 * sizeof(void*) + sizeof(S64) + 6 * sizeof(int)
         && sizeof(ZSTD_rust_frameChunkState)
                == 12 * sizeof(void*) + sizeof(S64) + 6 * sizeof(int))
        ? 1 : -1];
/* The target-sized block body only needs this narrow projection of ZSTD_CCtx.
 * Matchfinder/window state, sequence-store construction, and outer repeat-mode
 * cleanup remain in C. */
typedef struct {
    const SeqStore_t* seqStore;
    ZSTD_compressedBlockState_t** prevCBlock;
    ZSTD_compressedBlockState_t** nextCBlock;
    void* tmpWorkspace;
    size_t tmpWkspSize;
    int strategy;
    int disableLiteralCompression;
    int bmi2;
    U32 windowLog;
    size_t targetCBlockSize;
    int isFirstBlock;
} ZSTD_rust_targetCBlockSizeState;
size_t ZSTD_rust_compressBlockTargetCBlockSize(
        const ZSTD_rust_targetCBlockSizeState* state,
        void* dst, size_t dstCapacity,
        const void* src, size_t srcSize,
        int bss, U32 lastBlock);
typedef char ZSTD_rust_target_cblock_state_layout[
        (offsetof(ZSTD_rust_targetCBlockSizeState, seqStore) == 0
         && offsetof(ZSTD_rust_targetCBlockSizeState, prevCBlock) == sizeof(void*)
         && offsetof(ZSTD_rust_targetCBlockSizeState, nextCBlock) == 2 * sizeof(void*)
         && offsetof(ZSTD_rust_targetCBlockSizeState, tmpWorkspace) == 3 * sizeof(void*)
         && offsetof(ZSTD_rust_targetCBlockSizeState, tmpWkspSize) == 4 * sizeof(void*)
         && offsetof(ZSTD_rust_targetCBlockSizeState, strategy) == 5 * sizeof(void*)
         && offsetof(ZSTD_rust_targetCBlockSizeState, disableLiteralCompression)
                == 5 * sizeof(void*) + sizeof(int)
         && offsetof(ZSTD_rust_targetCBlockSizeState, bmi2)
                == 5 * sizeof(void*) + 2 * sizeof(int)
         && offsetof(ZSTD_rust_targetCBlockSizeState, windowLog)
                == 5 * sizeof(void*) + 3 * sizeof(int)
         && offsetof(ZSTD_rust_targetCBlockSizeState, targetCBlockSize)
                == 5 * sizeof(void*) + 4 * sizeof(int)
         && offsetof(ZSTD_rust_targetCBlockSizeState, isFirstBlock)
                == 5 * sizeof(void*) + 4 * sizeof(int) + sizeof(size_t)
         && sizeof(ZSTD_rust_targetCBlockSizeState)
                == (sizeof(void*) == 8 ? 72 : 44))
        ? 1 : -1];
/* The post-split partition loop only needs this projection of ZSTD_CCtx.
 * Split discovery remains in the surrounding C function; the Rust body owns
 * partition accounting, repcode simulation, and per-partition emission. */
typedef struct {
    const SeqStore_t* seqStore;
    const U32* partitions;
    SeqStore_t* nextSeqStore;
    SeqStore_t* currSeqStore;
    ZSTD_compressedBlockState_t** prevCBlock;
    ZSTD_compressedBlockState_t** nextCBlock;
    void* tmpWorkspace;
    size_t tmpWkspSize;
    SeqCollector* seqCollector;
    size_t blockSizeMax;
    int strategy;
    int disableLiteralCompression;
    int bmi2;
    int isFirstBlock;
} ZSTD_rust_splitBlockState;
size_t ZSTD_rust_compressBlockSplit(
        const ZSTD_rust_splitBlockState* state,
        void* dst, size_t dstCapacity,
        const void* src, size_t blockSize,
        U32 lastBlock, size_t numSplits);
typedef char ZSTD_rust_split_block_state_layout[
        (offsetof(ZSTD_rust_splitBlockState, seqStore) == 0
         && offsetof(ZSTD_rust_splitBlockState, partitions) == sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, nextSeqStore) == 2 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, currSeqStore) == 3 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, prevCBlock) == 4 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, nextCBlock) == 5 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, tmpWorkspace) == 6 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, tmpWkspSize) == 7 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, seqCollector) == 8 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, blockSizeMax) == 9 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, strategy) == 10 * sizeof(void*)
         && offsetof(ZSTD_rust_splitBlockState, disableLiteralCompression)
                == 10 * sizeof(void*) + sizeof(int)
         && offsetof(ZSTD_rust_splitBlockState, bmi2)
                == 10 * sizeof(void*) + 2 * sizeof(int)
         && offsetof(ZSTD_rust_splitBlockState, isFirstBlock)
                == 10 * sizeof(void*) + 3 * sizeof(int)
         && sizeof(ZSTD_rust_splitBlockState)
                == 10 * sizeof(void*) + 4 * sizeof(int))
        ? 1 : -1];
/* The ordinary sequence-block body only needs this projection of ZSTD_CCtx.
 * Sequence-store construction and the no-compress fallback remain in C. */
typedef struct {
    const SeqStore_t* seqStore;
    ZSTD_compressedBlockState_t** prevCBlock;
    ZSTD_compressedBlockState_t** nextCBlock;
    void* tmpWorkspace;
    size_t tmpWkspSize;
    SeqCollector* seqCollector;
    int strategy;
    int disableLiteralCompression;
    int bmi2;
    int isFirstBlock;
} ZSTD_rust_blockInternalState;
size_t ZSTD_rust_compressBlockInternal(
        const ZSTD_rust_blockInternalState* state,
        void* dst, size_t dstCapacity,
        const void* src, size_t srcSize,
        U32 frame);
typedef char ZSTD_rust_block_internal_state_layout[
        (offsetof(ZSTD_rust_blockInternalState, seqStore) == 0
         && offsetof(ZSTD_rust_blockInternalState, prevCBlock) == sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, nextCBlock) == 2 * sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, tmpWorkspace) == 3 * sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, tmpWkspSize) == 4 * sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, seqCollector) == 5 * sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, strategy) == 6 * sizeof(void*)
         && offsetof(ZSTD_rust_blockInternalState, disableLiteralCompression)
                == 6 * sizeof(void*) + sizeof(int)
         && offsetof(ZSTD_rust_blockInternalState, bmi2)
                == 6 * sizeof(void*) + 2 * sizeof(int)
         && offsetof(ZSTD_rust_blockInternalState, isFirstBlock)
                == 6 * sizeof(void*) + 3 * sizeof(int)
         && sizeof(ZSTD_rust_blockInternalState)
                == 6 * sizeof(void*) + 4 * sizeof(int))
        ? 1 : -1];
size_t ZSTD_rust_nextInputSizeHint(int inBufferMode,
                                   size_t blockSizeMax,
                                   size_t stableInNotConsumed,
                                   size_t inBuffTarget,
                                   size_t inBuffPos);
size_t ZSTD_rust_CStreamInSize(void);
size_t ZSTD_rust_CStreamOutSize(void);
size_t ZSTD_rust_sizeofCDict(size_t objectSize, size_t workspaceSize);
size_t ZSTD_rust_sizeofLocalDict(int dictBufferPresent, size_t dictSize,
                                 size_t cdictSize);
size_t ZSTD_rust_sizeofCCtx(size_t objectSize, size_t workspaceSize,
                            size_t localDictSize, size_t mtctxSize);
size_t ZSTD_rust_estimateWorkspaceSize(size_t cctxSpace,
                                       size_t tmpWorkSpace,
                                       size_t blockStateSpace,
                                       size_t ldmSpace,
                                       size_t ldmSeqSpace,
                                       size_t matchStateSize,
                                       size_t tokenSpace,
                                       size_t bufferSpace,
                                       size_t externalSeqSpace);
size_t ZSTD_rust_maxEstimateCCtxSize(size_t estimate0, size_t estimate1,
                                     size_t estimate2, size_t estimate3);
ZSTD_inBuffer ZSTD_rust_inBufferForEndFlush(int inBufferMode,
                                            const void* expectedSrc,
                                            size_t expectedSize,
                                            size_t expectedPos);
size_t ZSTD_rust_endStreamRemaining(size_t remainingToFlush,
                                    int frameEnded, int checksumFlag);
size_t ZSTD_rust_checkBufferStability(
        int inBufferMode, int outBufferMode,
        const void* expectedInSrc, size_t expectedInPos,
        const void* inputSrc, size_t inputPos,
        size_t expectedOutBufferSize, size_t outputSize, size_t outputPos);

/* Context-free compression-parameter selection and sizing leaves live in
 * Rust (rust/src/zstd_compress_params.rs).  This file retains
 * configuration-sensitive policy: the C-preprocessor construction of the
 * excluded-block-compressor mask, private ZSTD_CCtx_params handling, and
 * sanitizer workspace policy, which it feeds to the leaves as explicit
 * scalar inputs.  The ZSTD_CParamMode_e and ZSTD_ParamSwitch_e enums are
 * passed as int; the Rust side mirrors their values. */
int ZSTD_rust_params_maxCLevel(void);
int ZSTD_rust_params_minCLevel(void);
int ZSTD_rust_params_defaultCLevel(void);
ZSTD_bounds ZSTD_rust_params_getBounds(int param);
size_t ZSTD_rust_params_checkCParams(ZSTD_compressionParameters cParams);
void ZSTD_rust_params_assertEqualCParams(ZSTD_compressionParameters cParams1,
                                         ZSTD_compressionParameters cParams2);
ZSTD_compressionParameters
ZSTD_rust_params_clampCParams(ZSTD_compressionParameters cParams);
U32 ZSTD_rust_params_cycleLog(U32 hashLog, int strategy);
ZSTD_compressionParameters
ZSTD_rust_params_selectCParams(int compressionLevel, U64 srcSizeHint,
                               size_t dictSize, int mode);
ZSTD_compressionParameters
ZSTD_rust_params_adjustCParams(ZSTD_compressionParameters cParams, U64 srcSize,
                               size_t dictSize, int mode,
                               int useRowMatchFinder);
ZSTD_compressionParameters ZSTD_rust_params_getCParamsInternal(
        int compressionLevel, U64 srcSizeHint, size_t dictSize, int mode,
        U32 exclusionMask);
ZSTD_parameters ZSTD_rust_params_getParamsInternal(
        int compressionLevel, U64 srcSizeHint, size_t dictSize, int mode,
        U32 exclusionMask);
ZSTD_compressionParameters ZSTD_rust_params_getCParams(
        int compressionLevel, U64 srcSizeHint, size_t dictSize,
        U32 exclusionMask);
ZSTD_parameters ZSTD_rust_params_getParams(
        int compressionLevel, U64 srcSizeHint, size_t dictSize,
        U32 exclusionMask);
ZSTD_compressionParameters ZSTD_rust_params_applyStrategyExclusions(
        ZSTD_compressionParameters cParams, U32 exclusionMask);
ZSTD_compressionParameters ZSTD_rust_params_getCParamsFromCCtxParams(
        int compressionLevel, int cctxSrcSizeHint, U64 srcSizeHint,
        size_t dictSize, int mode, int enableLdm, U32 ldmDefaultWindowLog,
        ZSTD_compressionParameters overrides, int useRowMatchFinder,
        U32 exclusionMask);
ZSTD_parameters ZSTD_rust_params_makeParams(ZSTD_compressionParameters cParams);
size_t ZSTD_rust_params_maxNbSeq(size_t blockSize, U32 minMatch,
                                 int useSequenceProducer);
size_t ZSTD_rust_params_resolveMaxBlockSize(size_t maxBlockSize);
size_t ZSTD_rust_params_getBlockSize(size_t maxBlockSize, U32 windowLog);
void ZSTD_rust_params_overrideCParams(ZSTD_compressionParameters* cParams,
                                      const ZSTD_compressionParameters* overrides);
int ZSTD_rust_params_resolveExternalSequenceValidation(int mode);
int ZSTD_rust_params_rowMatchFinderSupported(int strategy);
int ZSTD_rust_params_rowMatchFinderUsed(int strategy, int mode);
int ZSTD_rust_params_selectBlockCompressor(int strategy, int mode);
int ZSTD_rust_params_resolveRowMatchFinderMode(
        int mode, ZSTD_compressionParameters cParams);
int ZSTD_rust_params_resolveBlockSplitterMode(
        int mode, ZSTD_compressionParameters cParams);
int ZSTD_rust_params_allocateChainTable(int strategy, int mode, int forDDSDict);
int ZSTD_rust_params_resolveEnableLdm(
        int mode, ZSTD_compressionParameters cParams);
int ZSTD_rust_params_resolveExternalRepcodeSearch(int mode, int cLevel);
int ZSTD_rust_params_cdictIndicesAreTagged(ZSTD_compressionParameters cParams);
int ZSTD_rust_params_dedicatedDictSearchIsSupported(ZSTD_compressionParameters cParams);
ZSTD_compressionParameters
ZSTD_rust_params_dedicatedDictSearch_getCParams(ZSTD_compressionParameters cParams);
ZSTD_compressionParameters
ZSTD_rust_params_dedicatedDictSearch_revertCParams(ZSTD_compressionParameters cParams);
int ZSTD_rust_params_shouldAttachDict(int strategy, int dedicatedDictSearch,
                                      U64 pledgedSrcSize, int attachDictPref,
                                      int forceWindow);
int ZSTD_rust_params_getCParamMode(int cdict_present, int cdict_strategy,
                                   int cdict_dedicated_search,
                                   U64 pledgedSrcSize,
                                   int params_attachDictPref,
                                   int params_forceWindow);

/* CCtx parameter state is mirrored by rust/src/zstd_compress_params_api.rs.
 * Rust owns parameter bounds and clamping; C exposes only the
 * build-configuration values required by that narrow ABI. */
ZSTD_bounds ZSTD_rust_cctx_params_get_bounds(int param);
size_t ZSTD_rust_cctx_params_clamp_bounds(int param, int* value);
int ZSTD_rust_cctx_params_within_bounds(int param, int value);
int ZSTD_rust_cctx_params_is_multithreaded(void);
int ZSTD_rust_cctx_params_nb_workers_max(void);
int ZSTD_rust_cctx_params_job_size_min(void);
int ZSTD_rust_cctx_params_job_size_max(void);
int ZSTD_rust_isUpdateAuthorized(int param);
ZSTD_CCtx_params* ZSTD_rust_createCCtxParams(ZSTD_customMem customMem);
size_t ZSTD_rust_freeCCtxParams(ZSTD_CCtx_params* params);
size_t ZSTD_rust_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams,
                                          ZSTD_parameters params);
void ZSTD_rust_CCtxParams_setZstdParams(ZSTD_CCtx_params* cctxParams,
                                        const ZSTD_parameters* params);
int ZSTD_rust_useTargetCBlockSize(const ZSTD_CCtx_params* cctxParams);
int ZSTD_rust_blockSplitterEnabled(ZSTD_CCtx_params* cctxParams);

#define ZSTD_RUST_CCTX_PARAMS_ASSERT(name, condition) \
    typedef char name[(condition) ? 1 : -1]
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_ldm_size, sizeof(ldmParams_t) == 24);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_custom_mem_size,
                             sizeof(ZSTD_customMem) == (sizeof(void*) == 8 ? 24 : 12));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_size,
                             sizeof(ZSTD_CCtx_params) == (sizeof(void*) == 8 ? 224 : 180));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_format_offset,
                             offsetof(ZSTD_CCtx_params, format) == 0);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_cparams_offset,
                             offsetof(ZSTD_CCtx_params, cParams) == 4);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_fparams_offset,
                             offsetof(ZSTD_CCtx_params, fParams) == 32);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_level_offset,
                             offsetof(ZSTD_CCtx_params, compressionLevel) == 44);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_force_window_offset,
                             offsetof(ZSTD_CCtx_params, forceWindow) == 48);
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_target_block_offset,
                             offsetof(ZSTD_CCtx_params, targetCBlockSize) == (sizeof(void*) == 8 ? 56 : 52));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_src_hint_offset,
                             offsetof(ZSTD_CCtx_params, srcSizeHint) == (sizeof(void*) == 8 ? 64 : 56));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_attach_offset,
                             offsetof(ZSTD_CCtx_params, attachDictPref) == (sizeof(void*) == 8 ? 68 : 60));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_literal_mode_offset,
                             offsetof(ZSTD_CCtx_params, literalCompressionMode) == (sizeof(void*) == 8 ? 72 : 64));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_workers_offset,
                             offsetof(ZSTD_CCtx_params, nbWorkers) == (sizeof(void*) == 8 ? 76 : 68));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_job_size_offset,
                             offsetof(ZSTD_CCtx_params, jobSize) == (sizeof(void*) == 8 ? 80 : 72));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_overlap_offset,
                             offsetof(ZSTD_CCtx_params, overlapLog) == (sizeof(void*) == 8 ? 88 : 76));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_rsyncable_offset,
                             offsetof(ZSTD_CCtx_params, rsyncable) == (sizeof(void*) == 8 ? 92 : 80));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_ldm_offset,
                             offsetof(ZSTD_CCtx_params, ldmParams) == (sizeof(void*) == 8 ? 96 : 84));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_dedicated_dict_offset,
                             offsetof(ZSTD_CCtx_params, enableDedicatedDictSearch) == (sizeof(void*) == 8 ? 120 : 108));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_in_buffer_offset,
                             offsetof(ZSTD_CCtx_params, inBufferMode) == (sizeof(void*) == 8 ? 124 : 112));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_out_buffer_offset,
                             offsetof(ZSTD_CCtx_params, outBufferMode) == (sizeof(void*) == 8 ? 128 : 116));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_delimiters_offset,
                             offsetof(ZSTD_CCtx_params, blockDelimiters) == (sizeof(void*) == 8 ? 132 : 120));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_validate_offset,
                             offsetof(ZSTD_CCtx_params, validateSequences) == (sizeof(void*) == 8 ? 136 : 124));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_post_splitter_offset,
                             offsetof(ZSTD_CCtx_params, postBlockSplitter) == (sizeof(void*) == 8 ? 140 : 128));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_pre_splitter_offset,
                             offsetof(ZSTD_CCtx_params, preBlockSplitter_level) == (sizeof(void*) == 8 ? 144 : 132));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_max_block_offset,
                             offsetof(ZSTD_CCtx_params, maxBlockSize) == (sizeof(void*) == 8 ? 152 : 136));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_row_matcher_offset,
                             offsetof(ZSTD_CCtx_params, useRowMatchFinder) == (sizeof(void*) == 8 ? 160 : 140));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_deterministic_prefix_offset,
                             offsetof(ZSTD_CCtx_params, deterministicRefPrefix) == (sizeof(void*) == 8 ? 164 : 144));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_custom_mem_offset,
                             offsetof(ZSTD_CCtx_params, customMem) == (sizeof(void*) == 8 ? 168 : 148));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_prefetch_offset,
                             offsetof(ZSTD_CCtx_params, prefetchCDictTables) == (sizeof(void*) == 8 ? 192 : 160));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_fallback_offset,
                             offsetof(ZSTD_CCtx_params, enableMatchFinderFallback) == (sizeof(void*) == 8 ? 196 : 164));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_state_offset,
                             offsetof(ZSTD_CCtx_params, extSeqProdState) == (sizeof(void*) == 8 ? 200 : 168));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_function_offset,
                             offsetof(ZSTD_CCtx_params, extSeqProdFunc) == (sizeof(void*) == 8 ? 208 : 172));
ZSTD_RUST_CCTX_PARAMS_ASSERT(ZSTD_rust_cctx_params_repcode_offset,
                             offsetof(ZSTD_CCtx_params, searchForExternalRepcodes) == (sizeof(void*) == 8 ? 216 : 176));
#undef ZSTD_RUST_CCTX_PARAMS_ASSERT

typedef struct {
    U32 hashLog3Max;
    size_t matchTSize;
    size_t optimalTSize;
    size_t asanRedzoneSize;
} ZSTD_rustMatchStateSizing;
size_t ZSTD_rust_params_estimateMatchStateSize(
        ZSTD_compressionParameters cParams, int useRowMatchFinder,
        int enableDedicatedDictSearch, U32 forCCtx,
        const ZSTD_rustMatchStateSizing* sizing);

typedef struct {
    size_t cdictSize;
    size_t hufWorkspaceSize;
    U32 hashLog3Max;
    size_t matchTSize;
    size_t optimalTSize;
    size_t asanRedzoneSize;
} ZSTD_rustCDictSizing;
size_t ZSTD_rust_params_estimateCDictSizeFromCParams(
        size_t dictSize, ZSTD_compressionParameters cParams,
        int dictLoadMethod, const ZSTD_rustCDictSizing* sizing);

/* Sequence statistics and seqStore entropy compression live in Rust
 * (rust/src/zstd_compress_stats.rs), which also exports ZSTD_seqToCodes()
 * under its original name.  The shims below extract the sequence store, the
 * entropy-table leaves, and the only two ZSTD_CCtx_params fields these paths
 * read (the strategy and the literals-compression switch), so the private
 * parameter structure layout never crosses the language boundary.  The
 * shared leaf layouts are pinned by the compile-time asserts that follow. */
size_t ZSTD_rust_entropyCompressSeqStore_internal(
        void* dst, size_t dstCapacity,
        const void* literals, size_t litSize,
        const SeqStore_t* seqStorePtr,
        const ZSTD_entropyCTables_t* prevEntropy,
        ZSTD_entropyCTables_t* nextEntropy,
        int strategy, int disableLiteralCompression,
        void* entropyWorkspace, size_t entropyWkspSize,
        int bmi2);
size_t ZSTD_rust_buildBlockEntropyStats(
        const SeqStore_t* seqStorePtr,
        const ZSTD_entropyCTables_t* prevEntropy,
        ZSTD_entropyCTables_t* nextEntropy,
        int strategy, int disableLiteralCompression,
        ZSTD_entropyCTablesMetadata_t* entropyMetadata,
        void* workspace, size_t wkspSize);
void ZSTD_rust_resetCompressedBlockState(ZSTD_compressedBlockState_t* bs);
void ZSTD_rust_invalidateRepCodes(U32 rep[ZSTD_REP_NUM]);
typedef char ZSTD_rust_invalidate_rep_count[(ZSTD_REP_NUM == 3) ? 1 : -1];
void ZSTD_rust_confirmRepcodesAndEntropyTables(
        ZSTD_compressedBlockState_t** prevCBlock,
        ZSTD_compressedBlockState_t** nextCBlock);
void ZSTD_rust_storeLastLiterals(SeqStore_t* seqStorePtr,
                                 const BYTE* anchor, size_t lastLLSize);
void ZSTD_rust_resetSeqStore(SeqStore_t* ssPtr);
size_t ZSTD_rust_fastSequenceLengthSum(const ZSTD_Sequence* seqBuf,
                                       size_t seqBufSize);
void ZSTD_rust_validateSeqStore(const SeqStore_t* seqStore, U32 minMatch);
size_t ZSTD_rust_convertSequencesNoRepcodes(
        SeqDef* dstSeqs, const ZSTD_Sequence* inSeqs, size_t nbSequences);
BlockSummary ZSTD_rust_get1BlockSummary(const ZSTD_Sequence* seqs,
                                        size_t nbSeqs);
size_t ZSTD_rust_postProcessSequenceProducerResult(
        ZSTD_Sequence* outSeqs, size_t nbExternalSeqs,
        size_t outSeqsCapacity, size_t srcSize);
size_t ZSTD_rust_deriveBlockSplits(
        U32* partitions, U32 nbSeq,
        const SeqStore_t* originalSeqStore,
        SeqStore_t* fullSeqStoreChunk,
        SeqStore_t* firstHalfSeqStore,
        SeqStore_t* secondHalfSeqStore,
        const ZSTD_entropyCTables_t* prevEntropy,
        ZSTD_entropyCTables_t* nextEntropy,
        int strategy, int disableLiteralCompression,
        ZSTD_entropyCTablesMetadata_t* entropyMetadata,
        void* workspace, size_t workspaceSize);
U32 ZSTD_rust_resolveRepcodeToRawOffset(const U32 rep[ZSTD_REP_NUM],
                                        U32 offBase, U32 ll0);
U32 ZSTD_rust_finalizeOffBase(U32 rawOffset, const U32 rep[ZSTD_REP_NUM], U32 ll0);
size_t ZSTD_rust_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
                              const void* dict, size_t dictSize);
size_t ZSTD_rust_transferSequencesWBlockDelim(
        SeqStore_t* seqStore, ZSTD_SequencePosition* seqPos,
        const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
        const BYTE* src, size_t blockSize, int externalRepSearch,
        const U32 prevRepcodes[ZSTD_REP_NUM],
        U32 nextRepcodes[ZSTD_REP_NUM], U32 dictSize,
        int validateSequences, U32 minMatch, U32 windowLog,
        int useSequenceProducer);
size_t ZSTD_rust_optimalBlockSize(const void* src, size_t srcSize,
                                  size_t blockSizeMax, int splitLevel,
                                  int strategy, S64 savings,
                                  void* workspace, size_t workspaceSize);

/* The sequence-compression loop receives only the state it actually reads or
 * updates.  In particular, neither ZSTD_CCtx nor a C function pointer crosses
 * the Rust ABI. */
typedef struct {
    SeqStore_t* seqStore;
    ZSTD_compressedBlockState_t** prevCBlock;
    ZSTD_compressedBlockState_t** nextCBlock;
    void* tmpWorkspace;
    size_t tmpWkspSize;
    size_t blockSizeMax;
    int bmi2;
    int blockDelimiters;
    int strategy;
    int disableLiteralCompression;
    int searchForExternalRepcodes;
    int validateSequences;
    U32 minMatch;
    U32 windowLog;
    U32 dictSize;
    int useSequenceProducer;
    int* isFirstBlock;
} ZSTD_rust_sequenceCompressionState;

size_t ZSTD_rust_compressSequencesInternal(
        const ZSTD_rust_sequenceCompressionState* state,
        void* dst, size_t dstCapacity,
        const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
        const void* src, size_t srcSize);

typedef char ZSTD_rust_sequence_state_layout[
        (offsetof(ZSTD_rust_sequenceCompressionState, seqStore) == 0
         && offsetof(ZSTD_rust_sequenceCompressionState, prevCBlock) == sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, nextCBlock) == 2 * sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, tmpWorkspace) == 3 * sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, tmpWkspSize) == 4 * sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, blockSizeMax) == 5 * sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, bmi2) == 6 * sizeof(void*)
         && offsetof(ZSTD_rust_sequenceCompressionState, minMatch)
                == 6 * sizeof(void*) + 6 * sizeof(int)
         && offsetof(ZSTD_rust_sequenceCompressionState, useSequenceProducer)
                == 6 * sizeof(void*) + 3 * sizeof(U32) + 6 * sizeof(int)
         && offsetof(ZSTD_rust_sequenceCompressionState, isFirstBlock)
                == 6 * sizeof(void*) + 3 * sizeof(U32) + 7 * sizeof(int)
         && sizeof(ZSTD_rust_sequenceCompressionState)
                == offsetof(ZSTD_rust_sequenceCompressionState, isFirstBlock) + sizeof(void*))
        ? 1 : -1];

typedef char ZSTD_rust_stats_seqdef_layout[(sizeof(SeqDef) == 8) ? 1 : -1];
typedef char ZSTD_rust_stats_block_summary_layout[
        (sizeof(BlockSummary) == 3 * sizeof(size_t)) ? 1 : -1];
typedef char ZSTD_rust_stats_seqstore_long_length_pos[
        (offsetof(SeqStore_t, longLengthPos) == 9 * sizeof(size_t) + 4) ? 1 : -1];
typedef char ZSTD_rust_stats_seqstore_layout[
        (sizeof(SeqStore_t) == 9 * sizeof(size_t) + 8) ? 1 : -1];
typedef char ZSTD_rust_stats_huf_layout[
        (sizeof(ZSTD_hufCTables_t) == 258 * sizeof(size_t)) ? 1 : -1];
typedef char ZSTD_rust_stats_fse_layout[(sizeof(ZSTD_fseCTables_t) == 3552) ? 1 : -1];
typedef char ZSTD_rust_stats_entropy_fse_offset[
        (offsetof(ZSTD_entropyCTables_t, fse) == sizeof(ZSTD_hufCTables_t)) ? 1 : -1];
typedef char ZSTD_rust_stats_huf_metadata_buffer[
        (offsetof(ZSTD_hufCTablesMetadata_t, hufDesBuffer) == 4
         && ZSTD_MAX_HUF_HEADER_SIZE == 128) ? 1 : -1];
typedef char ZSTD_rust_stats_fse_metadata_buffer[
        (offsetof(ZSTD_fseCTablesMetadata_t, fseTablesBuffer) == 12
         && ZSTD_MAX_FSE_HEADERS_SIZE == 133) ? 1 : -1];
typedef char ZSTD_rust_stats_entropy_metadata_layout[
        (offsetof(ZSTD_entropyCTablesMetadata_t, fseMetadata)
                == sizeof(ZSTD_hufCTablesMetadata_t)) ? 1 : -1];
typedef char ZSTD_rust_stats_sequence_layout[(sizeof(ZSTD_Sequence) == 16) ? 1 : -1];
typedef char ZSTD_rust_stats_sequence_position_layout[
        (sizeof(ZSTD_SequencePosition) == 2 * sizeof(U32) + sizeof(size_t)
         && offsetof(ZSTD_SequencePosition, posInSrc) == 2 * sizeof(U32)) ? 1 : -1];
typedef char ZSTD_rust_stats_seqcollector_layout[
        (offsetof(SeqCollector, seqStart) == sizeof(size_t)
         && offsetof(SeqCollector, seqIndex) == 2 * sizeof(size_t)
         && sizeof(SeqCollector) == 4 * sizeof(size_t)) ? 1 : -1];

#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
#  define ZSTD_RUST_ASAN_REDZONE_SIZE ((size_t)ZSTD_CWKSP_ASAN_REDZONE_SIZE)
#else
#  define ZSTD_RUST_ASAN_REDZONE_SIZE ((size_t)0)
#endif

/* ***************************************************************
*  Tuning parameters
*****************************************************************/
/*!
 * COMPRESS_HEAPMODE :
 * Select how default decompression function ZSTD_compress() allocates its context,
 * on stack (0, default), or into heap (1).
 * Note that functions with explicit context such as ZSTD_compressCCtx() are unaffected.
 */
#ifndef ZSTD_COMPRESS_HEAPMODE
#  define ZSTD_COMPRESS_HEAPMODE 0
#endif

/*!
 * ZSTD_HASHLOG3_MAX :
 * Maximum size of the hash table dedicated to find 3-bytes matches,
 * in log format, aka 17 => 1 << 17 == 128Ki positions.
 * This structure is only used in zstd_opt.
 * Since allocation is centralized for all strategies, it has to be known here.
 * The actual (selected) size of the hash table is then stored in ZSTD_MatchState_t.hashLog3,
 * so that zstd_opt.c doesn't need to know about this constant.
 */
#ifndef ZSTD_HASHLOG3_MAX
#  define ZSTD_HASHLOG3_MAX 17
#endif

/*-*************************************
*  Helper functions
***************************************/
/* ZSTD_compressBound() lives in rust/src/zstd_compress_api.rs.  Keep this
 * translation unit for the context implementation, which still calls the
 * exported ABI symbol. */


/*-*************************************
*  Context memory management
***************************************/
struct ZSTD_CDict_s {
    const void* dictContent;
    size_t dictContentSize;
    ZSTD_dictContentType_e dictContentType; /* The dictContentType the CDict was created with */
    U32* entropyWorkspace; /* entropy workspace of HUF_WORKSPACE_SIZE bytes */
    ZSTD_cwksp workspace;
    ZSTD_MatchState_t matchState;
    ZSTD_compressedBlockState_t cBlockState;
    ZSTD_customMem customMem;
    U32 dictID;
    int compressionLevel; /* 0 indicates that advanced API was used to select CDict params */
    ZSTD_ParamSwitch_e useRowMatchFinder; /* Indicates whether the CDict was created with params that would use
                                           * row-based matchfinder. Unless the cdict is reloaded, we will use
                                           * the same greedy/lazy matchfinder at compression time.
                                           */
};  /* typedef'd to ZSTD_CDict within "zstd.h" */

ZSTD_CCtx* ZSTD_createCCtx(void)
{
    return ZSTD_createCCtx_advanced(ZSTD_defaultCMem);
}

static void ZSTD_initCCtx(ZSTD_CCtx* cctx, ZSTD_customMem memManager)
{
    assert(cctx != NULL);
    ZSTD_memset(cctx, 0, sizeof(*cctx));
    cctx->customMem = memManager;
    cctx->bmi2 = ZSTD_cpuSupportsBmi2();
    {   size_t const err = ZSTD_CCtx_reset(cctx, ZSTD_reset_parameters);
        assert(!ZSTD_isError(err));
        (void)err;
    }
}

ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
{
    ZSTD_STATIC_ASSERT(zcss_init==0);
    ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1));
    if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
    {   ZSTD_CCtx* const cctx = (ZSTD_CCtx*)ZSTD_customMalloc(sizeof(ZSTD_CCtx), customMem);
        if (!cctx) return NULL;
        ZSTD_initCCtx(cctx, customMem);
        return cctx;
    }
}

ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize)
{
    ZSTD_cwksp ws;
    ZSTD_CCtx* cctx;
    if (workspaceSize <= sizeof(ZSTD_CCtx)) return NULL;  /* minimum size */
    if ((size_t)workspace & 7) return NULL;  /* must be 8-aligned */
    ZSTD_cwksp_init(&ws, workspace, workspaceSize, ZSTD_cwksp_static_alloc);

    cctx = (ZSTD_CCtx*)ZSTD_cwksp_reserve_object(&ws, sizeof(ZSTD_CCtx));
    if (cctx == NULL) return NULL;

    ZSTD_memset(cctx, 0, sizeof(ZSTD_CCtx));
    ZSTD_cwksp_move(&cctx->workspace, &ws);
    cctx->staticSize = workspaceSize;

    /* statically sized space. tmpWorkspace never moves (but prev/next block swap places) */
    if (!ZSTD_cwksp_check_available(&cctx->workspace, TMP_WORKSPACE_SIZE + 2 * sizeof(ZSTD_compressedBlockState_t))) return NULL;
    cctx->blockState.prevCBlock = (ZSTD_compressedBlockState_t*)ZSTD_cwksp_reserve_object(&cctx->workspace, sizeof(ZSTD_compressedBlockState_t));
    cctx->blockState.nextCBlock = (ZSTD_compressedBlockState_t*)ZSTD_cwksp_reserve_object(&cctx->workspace, sizeof(ZSTD_compressedBlockState_t));
    cctx->tmpWorkspace = ZSTD_cwksp_reserve_object(&cctx->workspace, TMP_WORKSPACE_SIZE);
    cctx->tmpWkspSize = TMP_WORKSPACE_SIZE;
    cctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
    return cctx;
}

/**
 * Clears and frees all of the dictionaries in the CCtx.
 */
static void ZSTD_clearAllDicts(ZSTD_CCtx* cctx)
{
    ZSTD_customFree(cctx->localDict.dictBuffer, cctx->customMem);
    ZSTD_freeCDict(cctx->localDict.cdict);
    ZSTD_memset(&cctx->localDict, 0, sizeof(cctx->localDict));
    ZSTD_memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));
    cctx->cdict = NULL;
}

static size_t ZSTD_sizeof_localDict(ZSTD_localDict dict)
{
    size_t const cdictSize = ZSTD_sizeof_CDict(dict.cdict);
    return ZSTD_rust_sizeofLocalDict(dict.dictBuffer != NULL, dict.dictSize,
                                     cdictSize);
}

static void ZSTD_freeCCtxContent(ZSTD_CCtx* cctx)
{
    assert(cctx != NULL);
    assert(cctx->staticSize == 0);
    ZSTD_clearAllDicts(cctx);
#ifdef ZSTD_MULTITHREAD
    ZSTDMT_freeCCtx(cctx->mtctx); cctx->mtctx = NULL;
#endif
    ZSTD_cwksp_free(&cctx->workspace, cctx->customMem);
}

size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
{
    DEBUGLOG(3, "ZSTD_freeCCtx (address: %p)", (void*)cctx);
    if (cctx==NULL) return 0;   /* support free on NULL */
    RETURN_ERROR_IF(cctx->staticSize, memory_allocation,
                    "not compatible with static CCtx");
    {   int cctxInWorkspace = ZSTD_cwksp_owns_buffer(&cctx->workspace, cctx);
        ZSTD_freeCCtxContent(cctx);
        if (!cctxInWorkspace) ZSTD_customFree(cctx, cctx->customMem);
    }
    return 0;
}


static size_t ZSTD_sizeof_mtctx(const ZSTD_CCtx* cctx)
{
#ifdef ZSTD_MULTITHREAD
    return ZSTDMT_sizeof_CCtx(cctx->mtctx);
#else
    (void)cctx;
    return 0;
#endif
}


size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx)
{
    if (cctx==NULL) return 0;   /* support sizeof on NULL */
    {
        /* cctx may be in the workspace */
        size_t const objectSize = cctx->workspace.workspace == cctx ? 0 : sizeof(*cctx);
        size_t const workspaceSize = ZSTD_cwksp_sizeof(&cctx->workspace);
        size_t const localDictSize = ZSTD_sizeof_localDict(cctx->localDict);
        size_t const mtctxSize = ZSTD_sizeof_mtctx(cctx);
        return ZSTD_rust_sizeofCCtx(objectSize, workspaceSize, localDictSize,
                                    mtctxSize);
    }
}

size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs)
{
    return ZSTD_sizeof_CCtx(zcs);  /* same object */
}

/* private API call, for dictBuilder only */
const SeqStore_t* ZSTD_getSeqStore(const ZSTD_CCtx* ctx) { return &(ctx->seqStore); }

/* Returns true if the strategy supports using a row based matchfinder */
static int ZSTD_rowMatchFinderSupported(const ZSTD_strategy strategy) {
    return ZSTD_rust_params_rowMatchFinderSupported((int)strategy);
}

/* Returns true if the strategy and useRowMatchFinder mode indicate that we will use the row based matchfinder
 * for this compression.
 */
static int ZSTD_rowMatchFinderUsed(const ZSTD_strategy strategy, const ZSTD_ParamSwitch_e mode) {
    assert(mode != ZSTD_ps_auto);
    return ZSTD_rust_params_rowMatchFinderUsed((int)strategy, (int)mode);
}

/* Returns row matchfinder usage given an initial mode and cParams */
static ZSTD_ParamSwitch_e ZSTD_resolveRowMatchFinderMode(ZSTD_ParamSwitch_e mode,
                                                         const ZSTD_compressionParameters* const cParams) {
    return (ZSTD_ParamSwitch_e)ZSTD_rust_params_resolveRowMatchFinderMode(
            (int)mode, *cParams);
}

/* Returns block splitter usage (generally speaking, when using slower/stronger compression modes) */
static ZSTD_ParamSwitch_e ZSTD_resolveBlockSplitterMode(ZSTD_ParamSwitch_e mode,
                                                        const ZSTD_compressionParameters* const cParams) {
    return (ZSTD_ParamSwitch_e)ZSTD_rust_params_resolveBlockSplitterMode(
            (int)mode, *cParams);
}

/* Returns 1 if the arguments indicate that we should allocate a chainTable, 0 otherwise */
static int ZSTD_allocateChainTable(const ZSTD_strategy strategy,
                                   const ZSTD_ParamSwitch_e useRowMatchFinder,
                                   const U32 forDDSDict) {
    assert(useRowMatchFinder != ZSTD_ps_auto);
    return ZSTD_rust_params_allocateChainTable(
            (int)strategy, (int)useRowMatchFinder, (int)forDDSDict);
}

/* Returns ZSTD_ps_enable if compression parameters are such that we should
 * enable long distance matching (wlog >= 27, strategy >= btopt).
 * Returns ZSTD_ps_disable otherwise.
 */
static ZSTD_ParamSwitch_e ZSTD_resolveEnableLdm(ZSTD_ParamSwitch_e mode,
                                 const ZSTD_compressionParameters* const cParams) {
    return (ZSTD_ParamSwitch_e)ZSTD_rust_params_resolveEnableLdm(
            (int)mode, *cParams);
}

static int ZSTD_resolveExternalSequenceValidation(int mode) {
    return ZSTD_rust_params_resolveExternalSequenceValidation(mode);
}

/* Resolves maxBlockSize to the default if no value is present. */
static size_t ZSTD_resolveMaxBlockSize(size_t maxBlockSize) {
    return ZSTD_rust_params_resolveMaxBlockSize(maxBlockSize);
}

static ZSTD_ParamSwitch_e ZSTD_resolveExternalRepcodeSearch(ZSTD_ParamSwitch_e value, int cLevel) {
    return (ZSTD_ParamSwitch_e)ZSTD_rust_params_resolveExternalRepcodeSearch(
            (int)value, cLevel);
}

/* Returns 1 if compression parameters are such that CDict hashtable and chaintable indices are tagged.
 * If so, the tags need to be removed in ZSTD_resetCCtx_byCopyingCDict. */
static int ZSTD_CDictIndicesAreTagged(const ZSTD_compressionParameters* const cParams) {
    return ZSTD_rust_params_cdictIndicesAreTagged(*cParams);
}

static ZSTD_CCtx_params ZSTD_makeCCtxParamsFromCParams(
        ZSTD_compressionParameters cParams)
{
    ZSTD_CCtx_params cctxParams;
    /* should not matter, as all cParams are presumed properly defined */
    ZSTD_CCtxParams_init(&cctxParams, ZSTD_CLEVEL_DEFAULT);
    cctxParams.cParams = cParams;

    /* Adjust advanced params according to cParams */
    cctxParams.ldmParams.enableLdm = ZSTD_resolveEnableLdm(cctxParams.ldmParams.enableLdm, &cParams);
    if (cctxParams.ldmParams.enableLdm == ZSTD_ps_enable) {
        ZSTD_ldm_adjustParameters(&cctxParams.ldmParams, &cParams);
        assert(cctxParams.ldmParams.hashLog >= cctxParams.ldmParams.bucketSizeLog);
        assert(cctxParams.ldmParams.hashRateLog < 32);
    }
    cctxParams.postBlockSplitter = ZSTD_resolveBlockSplitterMode(cctxParams.postBlockSplitter, &cParams);
    cctxParams.useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(cctxParams.useRowMatchFinder, &cParams);
    cctxParams.validateSequences = ZSTD_resolveExternalSequenceValidation(cctxParams.validateSequences);
    cctxParams.maxBlockSize = ZSTD_resolveMaxBlockSize(cctxParams.maxBlockSize);
    cctxParams.searchForExternalRepcodes = ZSTD_resolveExternalRepcodeSearch(cctxParams.searchForExternalRepcodes,
                                                                             cctxParams.compressionLevel);
    assert(!ZSTD_checkCParams(cParams));
    return cctxParams;
}

static ZSTD_CCtx_params* ZSTD_createCCtxParams_advanced(
        ZSTD_customMem customMem)
{
    return ZSTD_rust_createCCtxParams(customMem);
}

ZSTD_CCtx_params* ZSTD_createCCtxParams(void)
{
    return ZSTD_createCCtxParams_advanced(ZSTD_defaultCMem);
}

size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params)
{
    return ZSTD_rust_freeCCtxParams(params);
}

#define ZSTD_NO_CLEVEL 0

/**
 * Initializes `cctxParams` from `params` and `compressionLevel`.
 * @param compressionLevel If params are derived from a compression level then that compression level, otherwise ZSTD_NO_CLEVEL.
 */
static void
ZSTD_CCtxParams_init_internal(ZSTD_CCtx_params* cctxParams,
                        const ZSTD_parameters* params,
                              int compressionLevel)
{
    assert(!ZSTD_checkCParams(params->cParams));
    ZSTD_memset(cctxParams, 0, sizeof(*cctxParams));
    cctxParams->cParams = params->cParams;
    cctxParams->fParams = params->fParams;
    /* Should not matter, as all cParams are presumed properly defined.
     * But, set it for tracing anyway.
     */
    cctxParams->compressionLevel = compressionLevel;
    cctxParams->useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(cctxParams->useRowMatchFinder, &params->cParams);
    cctxParams->postBlockSplitter = ZSTD_resolveBlockSplitterMode(cctxParams->postBlockSplitter, &params->cParams);
    cctxParams->ldmParams.enableLdm = ZSTD_resolveEnableLdm(cctxParams->ldmParams.enableLdm, &params->cParams);
    cctxParams->validateSequences = ZSTD_resolveExternalSequenceValidation(cctxParams->validateSequences);
    cctxParams->maxBlockSize = ZSTD_resolveMaxBlockSize(cctxParams->maxBlockSize);
    cctxParams->searchForExternalRepcodes = ZSTD_resolveExternalRepcodeSearch(cctxParams->searchForExternalRepcodes, compressionLevel);
    DEBUGLOG(4, "ZSTD_CCtxParams_init_internal: useRowMatchFinder=%d, useBlockSplitter=%d ldm=%d",
                cctxParams->useRowMatchFinder, cctxParams->postBlockSplitter, cctxParams->ldmParams.enableLdm);
}

size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params)
{
    return ZSTD_rust_CCtxParams_init_advanced(cctxParams, params);
}

/**
 * Sets cctxParams' cParams and fParams from params, but otherwise leaves them alone.
 * @param params Validated zstd parameters.
 */
static void ZSTD_CCtxParams_setZstdParams(
        ZSTD_CCtx_params* cctxParams, const ZSTD_parameters* params)
{
    assert(!ZSTD_checkCParams(params->cParams));
    ZSTD_rust_CCtxParams_setZstdParams(cctxParams, params);
}

ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter param)
{
    return ZSTD_rust_cctx_params_get_bounds((int)param);
}

int ZSTD_rust_cctx_params_is_multithreaded(void)
{
#ifdef ZSTD_MULTITHREAD
    return 1;
#else
    return 0;
#endif
}

int ZSTD_rust_cctx_params_nb_workers_max(void)
{
#ifdef ZSTD_MULTITHREAD
    return ZSTDMT_NBWORKERS_MAX;
#else
    return 0;
#endif
}

int ZSTD_rust_cctx_params_job_size_min(void)
{
#ifdef ZSTD_MULTITHREAD
    return ZSTDMT_JOBSIZE_MIN;
#else
    return 0;
#endif
}

int ZSTD_rust_cctx_params_job_size_max(void)
{
#ifdef ZSTD_MULTITHREAD
    return ZSTDMT_JOBSIZE_MAX;
#else
    return 0;
#endif
}

#define BOUNDCHECK(cParam, val)                                       \
    do {                                                              \
        RETURN_ERROR_IF(!ZSTD_cParam_withinBounds(cParam,val),        \
                        parameter_outOfBound, "Param out of bounds"); \
    } while (0)


static int ZSTD_isUpdateAuthorized(ZSTD_cParameter param)
{
    return ZSTD_rust_isUpdateAuthorized((int)param);
}

size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value)
{
    DEBUGLOG(4, "ZSTD_CCtx_setParameter (%i, %i)", (int)param, value);
    if (cctx->streamStage != zcss_init) {
        if (ZSTD_isUpdateAuthorized(param)) {
            cctx->cParamsChanged = 1;
        } else {
            RETURN_ERROR(stage_wrong, "can only set params in cctx init stage");
    }   }

    switch(param)
    {
    case ZSTD_c_nbWorkers:
        RETURN_ERROR_IF((value!=0) && cctx->staticSize, parameter_unsupported,
                        "MT not compatible with static alloc");
        break;

    case ZSTD_c_compressionLevel:
    case ZSTD_c_windowLog:
    case ZSTD_c_hashLog:
    case ZSTD_c_chainLog:
    case ZSTD_c_searchLog:
    case ZSTD_c_minMatch:
    case ZSTD_c_targetLength:
    case ZSTD_c_strategy:
    case ZSTD_c_ldmHashRateLog:
    case ZSTD_c_format:
    case ZSTD_c_contentSizeFlag:
    case ZSTD_c_checksumFlag:
    case ZSTD_c_dictIDFlag:
    case ZSTD_c_forceMaxWindow:
    case ZSTD_c_forceAttachDict:
    case ZSTD_c_literalCompressionMode:
    case ZSTD_c_jobSize:
    case ZSTD_c_overlapLog:
    case ZSTD_c_rsyncable:
    case ZSTD_c_enableDedicatedDictSearch:
    case ZSTD_c_enableLongDistanceMatching:
    case ZSTD_c_ldmHashLog:
    case ZSTD_c_ldmMinMatch:
    case ZSTD_c_ldmBucketSizeLog:
    case ZSTD_c_targetCBlockSize:
    case ZSTD_c_srcSizeHint:
    case ZSTD_c_stableInBuffer:
    case ZSTD_c_stableOutBuffer:
    case ZSTD_c_blockDelimiters:
    case ZSTD_c_validateSequences:
    case ZSTD_c_splitAfterSequences:
    case ZSTD_c_blockSplitterLevel:
    case ZSTD_c_useRowMatchFinder:
    case ZSTD_c_deterministicRefPrefix:
    case ZSTD_c_prefetchCDictTables:
    case ZSTD_c_enableSeqProducerFallback:
    case ZSTD_c_maxBlockSize:
    case ZSTD_c_repcodeResolution:
        break;

    default: RETURN_ERROR(parameter_unsupported, "unknown parameter");
    }
    {   size_t const result = ZSTD_CCtxParams_setParameter(&cctx->requestedParams, param, value);
        if (!ZSTD_isError(result) && param == ZSTD_c_maxBlockSize) {
            cctx->rustSimpleCompress2MaxBlockSizeSet = 1;
        }
        return result;
    }
}

size_t ZSTD_CCtx_getParameter(ZSTD_CCtx const* cctx, ZSTD_cParameter param, int* value)
{
    return ZSTD_CCtxParams_getParameter(&cctx->requestedParams, param, value);
}

/** ZSTD_CCtx_setParametersUsingCCtxParams() :
 *  just applies `params` into `cctx`
 *  no action is performed, parameters are merely stored.
 *  If ZSTDMT is enabled, parameters are pushed to cctx->mtctx.
 *    This is possible even if a compression is ongoing.
 *    In which case, new parameters will be applied on the fly, starting with next compression job.
 */
size_t ZSTD_CCtx_setParametersUsingCCtxParams(
        ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params)
{
    DEBUGLOG(4, "ZSTD_CCtx_setParametersUsingCCtxParams");
    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                    "The context is in the wrong stage!");
    RETURN_ERROR_IF(cctx->cdict, stage_wrong,
                    "Can't override parameters with cdict attached (some must "
                    "be inherited from the cdict).");

    cctx->requestedParams = *params;
    return 0;
}

size_t ZSTD_CCtx_setCParams(ZSTD_CCtx* cctx, ZSTD_compressionParameters cparams)
{
    ZSTD_STATIC_ASSERT(sizeof(cparams) == 7 * 4 /* all params are listed below */);
    DEBUGLOG(4, "ZSTD_CCtx_setCParams");
    /* only update if all parameters are valid */
    FORWARD_IF_ERROR(ZSTD_checkCParams(cparams), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_windowLog, (int)cparams.windowLog), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_chainLog, (int)cparams.chainLog), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_hashLog, (int)cparams.hashLog), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_searchLog, (int)cparams.searchLog), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_minMatch, (int)cparams.minMatch), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_targetLength, (int)cparams.targetLength), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_strategy, (int)cparams.strategy), "");
    return 0;
}

size_t ZSTD_CCtx_setFParams(ZSTD_CCtx* cctx, ZSTD_frameParameters fparams)
{
    ZSTD_STATIC_ASSERT(sizeof(fparams) == 3 * 4 /* all params are listed below */);
    DEBUGLOG(4, "ZSTD_CCtx_setFParams");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_contentSizeFlag, fparams.contentSizeFlag != 0), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, fparams.checksumFlag != 0), "");
    FORWARD_IF_ERROR(ZSTD_CCtx_setParameter(cctx, ZSTD_c_dictIDFlag, fparams.noDictIDFlag == 0), "");
    return 0;
}

size_t ZSTD_CCtx_setParams(ZSTD_CCtx* cctx, ZSTD_parameters params)
{
    DEBUGLOG(4, "ZSTD_CCtx_setParams");
    /* First check cParams, because we want to update all or none. */
    FORWARD_IF_ERROR(ZSTD_checkCParams(params.cParams), "");
    /* Next set fParams, because this could fail if the cctx isn't in init stage. */
    FORWARD_IF_ERROR(ZSTD_CCtx_setFParams(cctx, params.fParams), "");
    /* Finally set cParams, which should succeed. */
    FORWARD_IF_ERROR(ZSTD_CCtx_setCParams(cctx, params.cParams), "");
    return 0;
}

size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize)
{
    DEBUGLOG(4, "ZSTD_CCtx_setPledgedSrcSize to %llu bytes", pledgedSrcSize);
    return ZSTD_rust_setPledgedSrcSize((int)cctx->streamStage, pledgedSrcSize,
                                       &cctx->pledgedSrcSizePlusOne);
}

static ZSTD_compressionParameters ZSTD_dedicatedDictSearch_getCParams(
        int const compressionLevel,
        size_t const dictSize);
static void ZSTD_dedicatedDictSearch_revertCParams(
        ZSTD_compressionParameters* cParams);

/**
 * Initializes the local dictionary using requested parameters.
 * NOTE: Initialization does not employ the pledged src size,
 * because the dictionary may be used for multiple compressions.
 */
static size_t ZSTD_initLocalDict(ZSTD_CCtx* cctx)
{
    ZSTD_localDict* const dl = &cctx->localDict;
    if (dl->dict == NULL) {
        /* No local dictionary. */
        assert(dl->dictBuffer == NULL);
        assert(dl->cdict == NULL);
        assert(dl->dictSize == 0);
        return 0;
    }
    if (dl->cdict != NULL) {
        /* Local dictionary already initialized. */
        assert(cctx->cdict == dl->cdict);
        return 0;
    }
    assert(dl->dictSize > 0);
    assert(cctx->cdict == NULL);
    assert(cctx->prefixDict.dict == NULL);

    dl->cdict = ZSTD_createCDict_advanced2(
            dl->dict,
            dl->dictSize,
            ZSTD_dlm_byRef,
            dl->dictContentType,
            &cctx->requestedParams,
            cctx->customMem);
    RETURN_ERROR_IF(!dl->cdict, memory_allocation, "ZSTD_createCDict_advanced failed");
    cctx->cdict = dl->cdict;
    return 0;
}

size_t ZSTD_CCtx_loadDictionary_advanced(
        ZSTD_CCtx* cctx,
        const void* dict, size_t dictSize,
        ZSTD_dictLoadMethod_e dictLoadMethod,
        ZSTD_dictContentType_e dictContentType)
{
    DEBUGLOG(4, "ZSTD_CCtx_loadDictionary_advanced (size: %u)", (U32)dictSize);
    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                    "Can't load a dictionary when cctx is not in init stage.");
    ZSTD_clearAllDicts(cctx);  /* erase any previously set dictionary */
    if (dict == NULL || dictSize == 0)  /* no dictionary */
        return 0;
    if (dictLoadMethod == ZSTD_dlm_byRef) {
        cctx->localDict.dict = dict;
    } else {
        /* copy dictionary content inside CCtx to own its lifetime */
        void* dictBuffer;
        RETURN_ERROR_IF(cctx->staticSize, memory_allocation,
                        "static CCtx can't allocate for an internal copy of dictionary");
        dictBuffer = ZSTD_customMalloc(dictSize, cctx->customMem);
        RETURN_ERROR_IF(dictBuffer==NULL, memory_allocation,
                        "allocation failed for dictionary content");
        ZSTD_memcpy(dictBuffer, dict, dictSize);
        cctx->localDict.dictBuffer = dictBuffer;  /* owned ptr to free */
        cctx->localDict.dict = dictBuffer;        /* read-only reference */
    }
    cctx->localDict.dictSize = dictSize;
    cctx->localDict.dictContentType = dictContentType;
    return 0;
}

size_t ZSTD_CCtx_loadDictionary_byReference(
      ZSTD_CCtx* cctx, const void* dict, size_t dictSize)
{
    return ZSTD_CCtx_loadDictionary_advanced(
            cctx, dict, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto);
}

size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize)
{
    return ZSTD_CCtx_loadDictionary_advanced(
            cctx, dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto);
}


size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
{
    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                    "Can't ref a dict when ctx not in init stage.");
    /* Free the existing local cdict (if any) to save memory. */
    ZSTD_clearAllDicts(cctx);
    cctx->cdict = cdict;
    return 0;
}

size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool)
{
    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                    "Can't ref a pool when ctx not in init stage.");
    cctx->pool = pool;
    return 0;
}

size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize)
{
    return ZSTD_CCtx_refPrefix_advanced(cctx, prefix, prefixSize, ZSTD_dct_rawContent);
}

size_t ZSTD_CCtx_refPrefix_advanced(
        ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
{
    RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                    "Can't ref a prefix when ctx not in init stage.");
    ZSTD_clearAllDicts(cctx);
    if (prefix != NULL && prefixSize > 0) {
        cctx->prefixDict.dict = prefix;
        cctx->prefixDict.dictSize = prefixSize;
        cctx->prefixDict.dictContentType = dictContentType;
    }
    return 0;
}

/*! ZSTD_CCtx_reset() :
 *  Also dumps dictionary */
size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset)
{
    cctx->rustSimpleCompress2Completed = 0;
    if ( (reset == ZSTD_reset_session_only)
      || (reset == ZSTD_reset_session_and_parameters) ) {
        cctx->streamStage = zcss_init;
        cctx->pledgedSrcSizePlusOne = 0;
    }
    if ( (reset == ZSTD_reset_parameters)
      || (reset == ZSTD_reset_session_and_parameters) ) {
        RETURN_ERROR_IF(cctx->streamStage != zcss_init, stage_wrong,
                        "Reset parameters is only possible during init stage.");
        ZSTD_clearAllDicts(cctx);
        cctx->rustSimpleCompress2MaxBlockSizeSet = 0;
        return ZSTD_CCtxParams_reset(&cctx->requestedParams);
    }
    return 0;
}


/** ZSTD_checkCParams() :
    control CParam values remain within authorized range.
    @return : 0, or an error code if one value is beyond authorized range */
size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
{
    return ZSTD_rust_params_checkCParams(cParams);
}

/** ZSTD_clampCParams() :
 *  make CParam values within valid range.
 *  @return : valid CParams */
static ZSTD_compressionParameters
ZSTD_clampCParams(ZSTD_compressionParameters cParams)
{
    return ZSTD_rust_params_clampCParams(cParams);
}

/** ZSTD_cycleLog() :
 *  condition for correct operation : hashLog > 1 */
U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
{
    return ZSTD_rust_params_cycleLog(hashLog, (int)strat);
}

static U32 ZSTD_getCParamsExclusionMask(void);

/** ZSTD_adjustCParams_internal() :
 *  optimize `cPar` for a specified input (`srcSize` and `dictSize`).
 *  mostly downsize to reduce memory consumption and initialization latency.
 * `srcSize` can be ZSTD_CONTENTSIZE_UNKNOWN when not known.
 * `mode` is the mode for parameter adjustment. See docs for `ZSTD_CParamMode_e`.
 *  note : `srcSize==0` means 0!
 *  condition : cPar is presumed validated (can be checked using ZSTD_checkCParams()). */
static ZSTD_compressionParameters
ZSTD_adjustCParams_internal(ZSTD_compressionParameters cPar,
                            unsigned long long srcSize,
                            size_t dictSize,
                            ZSTD_CParamMode_e mode,
                            ZSTD_ParamSwitch_e useRowMatchFinder)
{
    assert(ZSTD_checkCParams(cPar)==0);

    /* Cascade the selected strategy down to the next-highest one built into
     * this binary.  The C preprocessor constructs the mask so Rust does not
     * need to mirror this build's active ZSTD_EXCLUDE_* definitions. */
    cPar = ZSTD_rust_params_applyStrategyExclusions(
            cPar, ZSTD_getCParamsExclusionMask());

    /* The remaining adjustment logic is context-free and lives in Rust.  The
     * short-cache and row-hash tag widths the leaf assumes are fixed
     * private-header constants; keep them checked here. */
    ZSTD_STATIC_ASSERT(ZSTD_SHORT_CACHE_TAG_BITS == 8);
    ZSTD_STATIC_ASSERT(ZSTD_ROW_HASH_TAG_BITS == 8);
    return ZSTD_rust_params_adjustCParams(cPar, (U64)srcSize, dictSize,
                                          (int)mode, (int)useRowMatchFinder);
}

ZSTD_compressionParameters
ZSTD_adjustCParams(ZSTD_compressionParameters cPar,
                   unsigned long long srcSize,
                   size_t dictSize)
{
    cPar = ZSTD_clampCParams(cPar);   /* resulting cPar is necessarily valid (all parameters within range) */
    if (srcSize == 0) srcSize = ZSTD_CONTENTSIZE_UNKNOWN;
    return ZSTD_adjustCParams_internal(cPar, srcSize, dictSize, ZSTD_cpm_unknown, ZSTD_ps_auto);
}

static ZSTD_compressionParameters ZSTD_getCParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode);
static ZSTD_parameters ZSTD_getParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode);

enum {
    ZSTD_RUST_PARAMS_EXCLUDE_BTULTRA = 1u << 0,
    ZSTD_RUST_PARAMS_EXCLUDE_BTOPT = 1u << 1,
    ZSTD_RUST_PARAMS_EXCLUDE_BTLAZY2 = 1u << 2,
    ZSTD_RUST_PARAMS_EXCLUDE_LAZY2 = 1u << 3,
    ZSTD_RUST_PARAMS_EXCLUDE_LAZY = 1u << 4,
    ZSTD_RUST_PARAMS_EXCLUDE_GREEDY = 1u << 5,
    ZSTD_RUST_PARAMS_EXCLUDE_DFAST = 1u << 6
};

static U32 ZSTD_getCParamsExclusionMask(void)
{
    U32 mask = 0;
#ifdef ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_BTULTRA;
#endif
#ifdef ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_BTOPT;
#endif
#ifdef ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_BTLAZY2;
#endif
#ifdef ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_LAZY2;
#endif
#ifdef ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_LAZY;
#endif
#ifdef ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_GREEDY;
#endif
#ifdef ZSTD_EXCLUDE_DFAST_BLOCK_COMPRESSOR
    mask |= ZSTD_RUST_PARAMS_EXCLUDE_DFAST;
#endif
    return mask;
}

ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
        const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode)
{
    return ZSTD_rust_params_getCParamsFromCCtxParams(
            CCtxParams->compressionLevel, CCtxParams->srcSizeHint,
            srcSizeHint, dictSize, (int)mode,
            (int)CCtxParams->ldmParams.enableLdm,
            ZSTD_LDM_DEFAULT_WINDOW_LOG, CCtxParams->cParams,
            (int)CCtxParams->useRowMatchFinder,
            ZSTD_getCParamsExclusionMask());
}

static size_t
ZSTD_sizeof_matchState(const ZSTD_compressionParameters* const cParams,
                       const ZSTD_ParamSwitch_e useRowMatchFinder,
                       const int enableDedicatedDictSearch,
                       const U32 forCCtx)
{
    ZSTD_rustMatchStateSizing sizing;
    sizing.hashLog3Max = ZSTD_HASHLOG3_MAX;
    sizing.matchTSize = sizeof(ZSTD_match_t);
    sizing.optimalTSize = sizeof(ZSTD_optimal_t);
    sizing.asanRedzoneSize = ZSTD_RUST_ASAN_REDZONE_SIZE;

    /* The Rust leaf hardcodes the frozen format bounds and workspace rules;
     * keep them checked against the private headers here. */
    ZSTD_STATIC_ASSERT(MaxML == 52 && MaxLL == 35 && MaxOff == 31);
    ZSTD_STATIC_ASSERT(Litbits == 8 && ZSTD_OPT_SIZE == 4099);
    ZSTD_STATIC_ASSERT(ZSTD_CWKSP_ALIGNMENT_BYTES == 64);
    /* tables are guaranteed to be sized in multiples of 64 bytes (or 16 uint32_t) */
    ZSTD_STATIC_ASSERT(ZSTD_HASHLOG_MIN >= 4 && ZSTD_WINDOWLOG_MIN >= 4 && ZSTD_CHAINLOG_MIN >= 4);
    assert(useRowMatchFinder != ZSTD_ps_auto);

    return ZSTD_rust_params_estimateMatchStateSize(*cParams,
                                                   (int)useRowMatchFinder,
                                                   enableDedicatedDictSearch,
                                                   forCCtx, &sizing);
}

/* Helper function for calculating memory requirements.
 * Gives a tighter bound than ZSTD_sequenceBound() by taking minMatch into account. */
static size_t ZSTD_maxNbSeq(size_t blockSize, unsigned minMatch, int useSequenceProducer) {
    return ZSTD_rust_params_maxNbSeq(blockSize, minMatch, useSequenceProducer);
}

static size_t ZSTD_estimateCCtxSize_usingCCtxParams_internal(
        const ZSTD_compressionParameters* cParams,
        const ldmParams_t* ldmParams,
        const int isStatic,
        const ZSTD_ParamSwitch_e useRowMatchFinder,
        const size_t buffInSize,
        const size_t buffOutSize,
        const U64 pledgedSrcSize,
        int useSequenceProducer,
        size_t maxBlockSize)
{
    size_t const windowSize = (size_t) BOUNDED(1ULL, 1ULL << cParams->windowLog, pledgedSrcSize);
    size_t const blockSize = MIN(ZSTD_resolveMaxBlockSize(maxBlockSize), windowSize);
    size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, cParams->minMatch, useSequenceProducer);
    size_t const tokenSpace = ZSTD_cwksp_alloc_size(WILDCOPY_OVERLENGTH + blockSize)
                            + ZSTD_cwksp_aligned64_alloc_size(maxNbSeq * sizeof(SeqDef))
                            + 3 * ZSTD_cwksp_alloc_size(maxNbSeq * sizeof(BYTE));
    size_t const tmpWorkSpace = ZSTD_cwksp_alloc_size(TMP_WORKSPACE_SIZE);
    size_t const blockStateSpace = 2 * ZSTD_cwksp_alloc_size(sizeof(ZSTD_compressedBlockState_t));
    size_t const matchStateSize = ZSTD_sizeof_matchState(cParams, useRowMatchFinder, /* enableDedicatedDictSearch */ 0, /* forCCtx */ 1);

    size_t const ldmSpace = ZSTD_ldm_getTableSize(*ldmParams);
    size_t const maxNbLdmSeq = ZSTD_ldm_getMaxNbSeq(*ldmParams, blockSize);
    size_t const ldmSeqSpace = ldmParams->enableLdm == ZSTD_ps_enable ?
        ZSTD_cwksp_aligned64_alloc_size(maxNbLdmSeq * sizeof(rawSeq)) : 0;


    size_t const bufferSpace = ZSTD_cwksp_alloc_size(buffInSize)
                             + ZSTD_cwksp_alloc_size(buffOutSize);

    size_t const cctxSpace = isStatic ? ZSTD_cwksp_alloc_size(sizeof(ZSTD_CCtx)) : 0;

    size_t const maxNbExternalSeq = ZSTD_sequenceBound(blockSize);
    size_t const externalSeqSpace = useSequenceProducer
        ? ZSTD_cwksp_aligned64_alloc_size(maxNbExternalSeq * sizeof(ZSTD_Sequence))
        : 0;

    size_t const neededSpace = ZSTD_rust_estimateWorkspaceSize(
        cctxSpace, tmpWorkSpace, blockStateSpace, ldmSpace, ldmSeqSpace,
        matchStateSize, tokenSpace, bufferSpace, externalSeqSpace);

    DEBUGLOG(5, "estimate workspace : %u", (U32)neededSpace);
    return neededSpace;
}

size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params)
{
    ZSTD_compressionParameters const cParams =
                ZSTD_getCParamsFromCCtxParams(params, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
    ZSTD_ParamSwitch_e const useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(params->useRowMatchFinder,
                                                                               &cParams);

    RETURN_ERROR_IF(params->nbWorkers > 0, GENERIC, "Estimate CCtx size is supported for single-threaded compression only.");
    /* estimateCCtxSize is for one-shot compression. So no buffers should
     * be needed. However, we still allocate two 0-sized buffers, which can
     * take space under ASAN. */
    return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
        &cParams, &params->ldmParams, 1, useRowMatchFinder, 0, 0, ZSTD_CONTENTSIZE_UNKNOWN, ZSTD_hasExtSeqProd(params), params->maxBlockSize);
}

size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
{
    ZSTD_CCtx_params initialParams = ZSTD_makeCCtxParamsFromCParams(cParams);
    if (ZSTD_rowMatchFinderSupported(cParams.strategy)) {
        /* Pick bigger of not using and using row-based matchfinder for greedy and lazy strategies */
        size_t noRowCCtxSize;
        size_t rowCCtxSize;
        initialParams.useRowMatchFinder = ZSTD_ps_disable;
        noRowCCtxSize = ZSTD_estimateCCtxSize_usingCCtxParams(&initialParams);
        initialParams.useRowMatchFinder = ZSTD_ps_enable;
        rowCCtxSize = ZSTD_estimateCCtxSize_usingCCtxParams(&initialParams);
        return MAX(noRowCCtxSize, rowCCtxSize);
    } else {
        return ZSTD_estimateCCtxSize_usingCCtxParams(&initialParams);
    }
}

static size_t ZSTD_estimateCCtxSize_internal(int compressionLevel)
{
    int tier = 0;
    size_t estimates[4];
    static const unsigned long long srcSizeTiers[4] = {16 KB, 128 KB, 256 KB, ZSTD_CONTENTSIZE_UNKNOWN};
    for (; tier < 4; ++tier) {
        /* Choose the set of cParams for a given level across all srcSizes that give the largest cctxSize */
        ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, srcSizeTiers[tier], 0, ZSTD_cpm_noAttachDict);
        estimates[tier] = ZSTD_estimateCCtxSize_usingCParams(cParams);
    }
    return ZSTD_rust_maxEstimateCCtxSize(
        estimates[0], estimates[1], estimates[2], estimates[3]);
}

size_t ZSTD_estimateCCtxSize(int compressionLevel)
{
    int level;
    size_t memBudget = 0;
    for (level=MIN(compressionLevel, 1); level<=compressionLevel; level++) {
        /* Ensure monotonically increasing memory usage as compression level increases */
        size_t const newMB = ZSTD_estimateCCtxSize_internal(level);
        if (newMB > memBudget) memBudget = newMB;
    }
    return memBudget;
}

size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params)
{
    RETURN_ERROR_IF(params->nbWorkers > 0, GENERIC, "Estimate CCtx size is supported for single-threaded compression only.");
    {   ZSTD_compressionParameters const cParams =
                ZSTD_getCParamsFromCCtxParams(params, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
        size_t const blockSize = MIN(ZSTD_resolveMaxBlockSize(params->maxBlockSize), (size_t)1 << cParams.windowLog);
        size_t const inBuffSize = (params->inBufferMode == ZSTD_bm_buffered)
                ? ((size_t)1 << cParams.windowLog) + blockSize
                : 0;
        size_t const outBuffSize = (params->outBufferMode == ZSTD_bm_buffered)
                ? ZSTD_compressBound(blockSize) + 1
                : 0;
        ZSTD_ParamSwitch_e const useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(params->useRowMatchFinder, &params->cParams);

        return ZSTD_estimateCCtxSize_usingCCtxParams_internal(
            &cParams, &params->ldmParams, 1, useRowMatchFinder, inBuffSize, outBuffSize,
            ZSTD_CONTENTSIZE_UNKNOWN, ZSTD_hasExtSeqProd(params), params->maxBlockSize);
    }
}

size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams)
{
    ZSTD_CCtx_params initialParams = ZSTD_makeCCtxParamsFromCParams(cParams);
    if (ZSTD_rowMatchFinderSupported(cParams.strategy)) {
        /* Pick bigger of not using and using row-based matchfinder for greedy and lazy strategies */
        size_t noRowCCtxSize;
        size_t rowCCtxSize;
        initialParams.useRowMatchFinder = ZSTD_ps_disable;
        noRowCCtxSize = ZSTD_estimateCStreamSize_usingCCtxParams(&initialParams);
        initialParams.useRowMatchFinder = ZSTD_ps_enable;
        rowCCtxSize = ZSTD_estimateCStreamSize_usingCCtxParams(&initialParams);
        return MAX(noRowCCtxSize, rowCCtxSize);
    } else {
        return ZSTD_estimateCStreamSize_usingCCtxParams(&initialParams);
    }
}

static size_t ZSTD_estimateCStreamSize_internal(int compressionLevel)
{
    ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
    return ZSTD_estimateCStreamSize_usingCParams(cParams);
}

size_t ZSTD_estimateCStreamSize(int compressionLevel)
{
    int level;
    size_t memBudget = 0;
    for (level=MIN(compressionLevel, 1); level<=compressionLevel; level++) {
        size_t const newMB = ZSTD_estimateCStreamSize_internal(level);
        if (newMB > memBudget) memBudget = newMB;
    }
    return memBudget;
}

/* ZSTD_getFrameProgression():
 * tells how much data has been consumed (input) and produced (output) for current frame.
 * able to count progression inside worker threads (non-blocking mode).
 */
ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx)
{
#ifdef ZSTD_MULTITHREAD
    if (cctx->appliedParams.nbWorkers > 0) {
        return ZSTDMT_getFrameProgression(cctx->mtctx);
    }
#endif
    {
        size_t const buffered = (cctx->inBuff == NULL) ? 0 :
                                cctx->inBuffPos - cctx->inToCompress;
        if (buffered) assert(cctx->inBuffPos >= cctx->inToCompress);
        assert(buffered <= ZSTD_BLOCKSIZE_MAX);
        return ZSTD_rust_frameProgression(cctx->consumedSrcSize, buffered,
                                          cctx->producedCSize);
    }   }

/*! ZSTD_toFlushNow()
 *  Only useful for multithreading scenarios currently (nbWorkers >= 1).
 */
size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx)
{
#ifdef ZSTD_MULTITHREAD
    if (cctx->appliedParams.nbWorkers > 0) {
        return ZSTDMT_toFlushNow(cctx->mtctx);
    }
#endif
    (void)cctx;
    return 0;   /* over-simplification; could also check if context is currently running in streaming mode, and in which case, report how many bytes are left to be flushed within output buffer */
}

static void ZSTD_assertEqualCParams(ZSTD_compressionParameters cParams1,
                                    ZSTD_compressionParameters cParams2)
{
    ZSTD_rust_params_assertEqualCParams(cParams1, cParams2);
}

void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs)
{
    ZSTD_rust_resetCompressedBlockState(bs);
}

/*! ZSTD_invalidateMatchState()
 *  Invalidate all the matches in the match finder tables.
 *  Requires nextSrc and base to be set (can be NULL).
 */
static void ZSTD_invalidateMatchState(ZSTD_MatchState_t* ms)
{
    ZSTD_rust_windowClear((size_t)(ms->window.nextSrc - ms->window.base),
                          &ms->window.lowLimit, &ms->window.dictLimit);

    ms->nextToUpdate = ms->window.dictLimit;
    ms->loadedDictEnd = 0;
    ms->opt.litLengthSum = 0;  /* force reset of btopt stats */
    ms->dictMatchState = NULL;
}

/**
 * Controls, for this matchState reset, whether the tables need to be cleared /
 * prepared for the coming compression (ZSTDcrp_makeClean), or whether the
 * tables can be left unclean (ZSTDcrp_leaveDirty), because we know that a
 * subsequent operation will overwrite the table space anyways (e.g., copying
 * the matchState contents in from a CDict).
 */
typedef enum {
    ZSTDcrp_makeClean,
    ZSTDcrp_leaveDirty
} ZSTD_compResetPolicy_e;

/**
 * Controls, for this matchState reset, whether indexing can continue where it
 * left off (ZSTDirp_continue), or whether it needs to be restarted from zero
 * (ZSTDirp_reset).
 */
typedef enum {
    ZSTDirp_continue,
    ZSTDirp_reset
} ZSTD_indexResetPolicy_e;

typedef enum {
    ZSTD_resetTarget_CDict,
    ZSTD_resetTarget_CCtx
} ZSTD_resetTarget_e;

/* Mixes in the hashSalt and hashSaltEntropy to create a new hashSalt */
static void ZSTD_advanceHashSalt(ZSTD_MatchState_t* ms) {
    ms->hashSalt = ZSTD_rust_advanceHashSalt(ms->hashSalt, (U64)ms->hashSaltEntropy);
}

static size_t
ZSTD_reset_matchState(ZSTD_MatchState_t* ms,
                      ZSTD_cwksp* ws,
                const ZSTD_compressionParameters* cParams,
                const ZSTD_ParamSwitch_e useRowMatchFinder,
                const ZSTD_compResetPolicy_e crp,
                const ZSTD_indexResetPolicy_e forceResetIndex,
                const ZSTD_resetTarget_e forWho)
{
    /* disable chain table allocation for fast or row-based strategies */
    size_t const chainSize = ZSTD_allocateChainTable(cParams->strategy, useRowMatchFinder,
                                                     ms->dedicatedDictSearch && (forWho == ZSTD_resetTarget_CDict))
                                ? ((size_t)1 << cParams->chainLog)
                                : 0;
    size_t const hSize = ((size_t)1) << cParams->hashLog;
    U32    const hashLog3 = ((forWho == ZSTD_resetTarget_CCtx) && cParams->minMatch==3) ? MIN(ZSTD_HASHLOG3_MAX, cParams->windowLog) : 0;
    size_t const h3Size = hashLog3 ? ((size_t)1) << hashLog3 : 0;

    DEBUGLOG(4, "reset indices : %u", forceResetIndex == ZSTDirp_reset);
    assert(useRowMatchFinder != ZSTD_ps_auto);
    if (forceResetIndex == ZSTDirp_reset) {
        ZSTD_window_init(&ms->window);
        ZSTD_cwksp_mark_tables_dirty(ws);
    }

    ms->hashLog3 = hashLog3;
    ms->lazySkipping = 0;

    ZSTD_invalidateMatchState(ms);

    assert(!ZSTD_cwksp_reserve_failed(ws)); /* check that allocation hasn't already failed */

    ZSTD_cwksp_clear_tables(ws);

    DEBUGLOG(5, "reserving table space");
    /* table Space */
    ms->hashTable = (U32*)ZSTD_cwksp_reserve_table(ws, hSize * sizeof(U32));
    ms->chainTable = (U32*)ZSTD_cwksp_reserve_table(ws, chainSize * sizeof(U32));
    ms->hashTable3 = (U32*)ZSTD_cwksp_reserve_table(ws, h3Size * sizeof(U32));
    RETURN_ERROR_IF(ZSTD_cwksp_reserve_failed(ws), memory_allocation,
                    "failed a workspace allocation in ZSTD_reset_matchState");

    DEBUGLOG(4, "reset table : %u", crp!=ZSTDcrp_leaveDirty);
    if (crp!=ZSTDcrp_leaveDirty) {
        /* reset tables only */
        ZSTD_cwksp_clean_tables(ws);
    }

    if (ZSTD_rowMatchFinderUsed(cParams->strategy, useRowMatchFinder)) {
        /* Row match finder needs an additional table of hashes ("tags") */
        size_t const tagTableSize = hSize;
        /* We want to generate a new salt in case we reset a Cctx, but we always want to use
         * 0 when we reset a Cdict */
        if(forWho == ZSTD_resetTarget_CCtx) {
            ms->tagTable = (BYTE*) ZSTD_cwksp_reserve_aligned_init_once(ws, tagTableSize);
            ZSTD_advanceHashSalt(ms);
        } else {
            /* When we are not salting we want to always memset the memory */
            ms->tagTable = (BYTE*) ZSTD_cwksp_reserve_aligned64(ws, tagTableSize);
            ZSTD_memset(ms->tagTable, 0, tagTableSize);
            ms->hashSalt = 0;
        }
        {   /* Switch to 32-entry rows if searchLog is 5 (or more) */
            U32 const rowLog = BOUNDED(4, cParams->searchLog, 6);
            assert(cParams->hashLog >= rowLog);
            ms->rowHashLog = cParams->hashLog - rowLog;
        }
    }

    /* opt parser space */
    if ((forWho == ZSTD_resetTarget_CCtx) && (cParams->strategy >= ZSTD_btopt)) {
        DEBUGLOG(4, "reserving optimal parser space");
        ms->opt.litFreq = (unsigned*)ZSTD_cwksp_reserve_aligned64(ws, (1<<Litbits) * sizeof(unsigned));
        ms->opt.litLengthFreq = (unsigned*)ZSTD_cwksp_reserve_aligned64(ws, (MaxLL+1) * sizeof(unsigned));
        ms->opt.matchLengthFreq = (unsigned*)ZSTD_cwksp_reserve_aligned64(ws, (MaxML+1) * sizeof(unsigned));
        ms->opt.offCodeFreq = (unsigned*)ZSTD_cwksp_reserve_aligned64(ws, (MaxOff+1) * sizeof(unsigned));
        ms->opt.matchTable = (ZSTD_match_t*)ZSTD_cwksp_reserve_aligned64(ws, ZSTD_OPT_SIZE * sizeof(ZSTD_match_t));
        ms->opt.priceTable = (ZSTD_optimal_t*)ZSTD_cwksp_reserve_aligned64(ws, ZSTD_OPT_SIZE * sizeof(ZSTD_optimal_t));
    }

    ms->cParams = *cParams;

    RETURN_ERROR_IF(ZSTD_cwksp_reserve_failed(ws), memory_allocation,
                    "failed a workspace allocation in ZSTD_reset_matchState");
    return 0;
}

/* ZSTD_indexTooCloseToMax() :
 * minor optimization : prefer memset() rather than reduceIndex()
 * which is measurably slow in some circumstances (reported for Visual Studio).
 * Works when re-using a context for a lot of smallish inputs :
 * if all inputs are smaller than ZSTD_INDEXOVERFLOW_MARGIN,
 * memset() will be triggered before reduceIndex().
 */
#define ZSTD_INDEXOVERFLOW_MARGIN (16 MB)
static int ZSTD_indexTooCloseToMax(ZSTD_window_t w)
{
    return ZSTD_rust_indexTooCloseToMax((size_t)(w.nextSrc - w.base));
}

/** ZSTD_dictTooBig():
 * When dictionaries are larger than ZSTD_CHUNKSIZE_MAX they can't be loaded in
 * one go generically. So we ensure that in that case we reset the tables to zero,
 * so that we can load as much of the dictionary as possible.
 */
static int ZSTD_dictTooBig(size_t const loadedDictSize)
{
    return ZSTD_rust_dictTooBig(loadedDictSize);
}

/*! ZSTD_resetCCtx_internal() :
 * @param loadedDictSize The size of the dictionary to be loaded
 * into the context, if any. If no dictionary is used, or the
 * dictionary is being attached / copied, then pass 0.
 * note : `params` are assumed fully validated at this stage.
 */
static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
                                      ZSTD_CCtx_params const* params,
                                      U64 const pledgedSrcSize,
                                      size_t const loadedDictSize,
                                      ZSTD_compResetPolicy_e const crp,
                                      ZSTD_buffered_policy_e const zbuff)
{
    ZSTD_cwksp* const ws = &zc->workspace;
    DEBUGLOG(4, "ZSTD_resetCCtx_internal: pledgedSrcSize=%u, wlog=%u, useRowMatchFinder=%d useBlockSplitter=%d",
                (U32)pledgedSrcSize, params->cParams.windowLog, (int)params->useRowMatchFinder, (int)params->postBlockSplitter);
    assert(!ZSTD_isError(ZSTD_checkCParams(params->cParams)));

    zc->isFirstBlock = 1;

    /* Set applied params early so we can modify them for LDM,
     * and point params at the applied params.
     */
    zc->appliedParams = *params;
    params = &zc->appliedParams;

    assert(params->useRowMatchFinder != ZSTD_ps_auto);
    assert(params->postBlockSplitter != ZSTD_ps_auto);
    assert(params->ldmParams.enableLdm != ZSTD_ps_auto);
    assert(params->maxBlockSize != 0);
    if (params->ldmParams.enableLdm == ZSTD_ps_enable) {
        /* Adjust long distance matching parameters */
        ZSTD_ldm_adjustParameters(&zc->appliedParams.ldmParams, &params->cParams);
        assert(params->ldmParams.hashLog >= params->ldmParams.bucketSizeLog);
        assert(params->ldmParams.hashRateLog < 32);
    }

    {   size_t const windowSize = MAX(1, (size_t)MIN(((U64)1 << params->cParams.windowLog), pledgedSrcSize));
        size_t const blockSize = MIN(params->maxBlockSize, windowSize);
        size_t const maxNbSeq = ZSTD_maxNbSeq(blockSize, params->cParams.minMatch, ZSTD_hasExtSeqProd(params));
        size_t const buffOutSize = (zbuff == ZSTDb_buffered && params->outBufferMode == ZSTD_bm_buffered)
                ? ZSTD_compressBound(blockSize) + 1
                : 0;
        size_t const buffInSize = (zbuff == ZSTDb_buffered && params->inBufferMode == ZSTD_bm_buffered)
                ? windowSize + blockSize
                : 0;
        size_t const maxNbLdmSeq = ZSTD_ldm_getMaxNbSeq(params->ldmParams, blockSize);

        int const indexTooClose = ZSTD_indexTooCloseToMax(zc->blockState.matchState.window);
        int const dictTooBig = ZSTD_dictTooBig(loadedDictSize);
        ZSTD_indexResetPolicy_e needsIndexReset =
            (indexTooClose || dictTooBig || !zc->initialized) ? ZSTDirp_reset : ZSTDirp_continue;

        size_t const neededSpace =
            ZSTD_estimateCCtxSize_usingCCtxParams_internal(
                &params->cParams, &params->ldmParams, zc->staticSize != 0, params->useRowMatchFinder,
                buffInSize, buffOutSize, pledgedSrcSize, ZSTD_hasExtSeqProd(params), params->maxBlockSize);

        FORWARD_IF_ERROR(neededSpace, "cctx size estimate failed!");

        if (!zc->staticSize) ZSTD_cwksp_bump_oversized_duration(ws, 0);

        {   /* Check if workspace is large enough, alloc a new one if needed */
            int const workspaceTooSmall = ZSTD_cwksp_sizeof(ws) < neededSpace;
            int const workspaceWasteful = ZSTD_cwksp_check_wasteful(ws, neededSpace);
            int resizeWorkspace = workspaceTooSmall || workspaceWasteful;
            DEBUGLOG(4, "Need %zu B workspace", neededSpace);
            DEBUGLOG(4, "windowSize: %zu - blockSize: %zu", windowSize, blockSize);

            if (resizeWorkspace) {
                DEBUGLOG(4, "Resize workspaceSize from %zuKB to %zuKB",
                            ZSTD_cwksp_sizeof(ws) >> 10,
                            neededSpace >> 10);

                RETURN_ERROR_IF(zc->staticSize, memory_allocation, "static cctx : no resize");

                needsIndexReset = ZSTDirp_reset;

                ZSTD_cwksp_free(ws, zc->customMem);
                FORWARD_IF_ERROR(ZSTD_cwksp_create(ws, neededSpace, zc->customMem), "");

                DEBUGLOG(5, "reserving object space");
                /* Statically sized space.
                 * tmpWorkspace never moves,
                 * though prev/next block swap places */
                assert(ZSTD_cwksp_check_available(ws, 2 * sizeof(ZSTD_compressedBlockState_t)));
                zc->blockState.prevCBlock = (ZSTD_compressedBlockState_t*) ZSTD_cwksp_reserve_object(ws, sizeof(ZSTD_compressedBlockState_t));
                RETURN_ERROR_IF(zc->blockState.prevCBlock == NULL, memory_allocation, "couldn't allocate prevCBlock");
                zc->blockState.nextCBlock = (ZSTD_compressedBlockState_t*) ZSTD_cwksp_reserve_object(ws, sizeof(ZSTD_compressedBlockState_t));
                RETURN_ERROR_IF(zc->blockState.nextCBlock == NULL, memory_allocation, "couldn't allocate nextCBlock");
                zc->tmpWorkspace = ZSTD_cwksp_reserve_object(ws, TMP_WORKSPACE_SIZE);
                RETURN_ERROR_IF(zc->tmpWorkspace == NULL, memory_allocation, "couldn't allocate tmpWorkspace");
                zc->tmpWkspSize = TMP_WORKSPACE_SIZE;
        }   }

        ZSTD_cwksp_clear(ws);

        /* init params */
        zc->blockState.matchState.cParams = params->cParams;
        zc->blockState.matchState.prefetchCDictTables = params->prefetchCDictTables == ZSTD_ps_enable;
        zc->pledgedSrcSizePlusOne = pledgedSrcSize+1;
        zc->consumedSrcSize = 0;
        zc->producedCSize = 0;
        if (pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN)
            zc->appliedParams.fParams.contentSizeFlag = 0;
        DEBUGLOG(4, "pledged content size : %u ; flag : %u",
            (unsigned)pledgedSrcSize, zc->appliedParams.fParams.contentSizeFlag);
        zc->blockSizeMax = blockSize;

        XXH64_reset(&zc->xxhState, 0);
        zc->stage = ZSTDcs_init;
        zc->dictID = 0;
        zc->dictContentSize = 0;

        ZSTD_reset_compressedBlockState(zc->blockState.prevCBlock);

        FORWARD_IF_ERROR(ZSTD_reset_matchState(
                &zc->blockState.matchState,
                ws,
                &params->cParams,
                params->useRowMatchFinder,
                crp,
                needsIndexReset,
                ZSTD_resetTarget_CCtx), "");

        zc->seqStore.sequencesStart = (SeqDef*)ZSTD_cwksp_reserve_aligned64(ws, maxNbSeq * sizeof(SeqDef));

        /* ldm hash table */
        if (params->ldmParams.enableLdm == ZSTD_ps_enable) {
            /* TODO: avoid memset? */
            size_t const ldmHSize = ((size_t)1) << params->ldmParams.hashLog;
            zc->ldmState.hashTable = (ldmEntry_t*)ZSTD_cwksp_reserve_aligned64(ws, ldmHSize * sizeof(ldmEntry_t));
            ZSTD_memset(zc->ldmState.hashTable, 0, ldmHSize * sizeof(ldmEntry_t));
            zc->ldmSequences = (rawSeq*)ZSTD_cwksp_reserve_aligned64(ws, maxNbLdmSeq * sizeof(rawSeq));
            zc->maxNbLdmSequences = maxNbLdmSeq;

            ZSTD_window_init(&zc->ldmState.window);
            zc->ldmState.loadedDictEnd = 0;
        }

        /* reserve space for block-level external sequences */
        if (ZSTD_hasExtSeqProd(params)) {
            size_t const maxNbExternalSeq = ZSTD_sequenceBound(blockSize);
            zc->extSeqBufCapacity = maxNbExternalSeq;
            zc->extSeqBuf =
                (ZSTD_Sequence*)ZSTD_cwksp_reserve_aligned64(ws, maxNbExternalSeq * sizeof(ZSTD_Sequence));
        }

        /* buffers */

        /* ZSTD_wildcopy() is used to copy into the literals buffer,
         * so we have to oversize the buffer by WILDCOPY_OVERLENGTH bytes.
         */
        zc->seqStore.litStart = ZSTD_cwksp_reserve_buffer(ws, blockSize + WILDCOPY_OVERLENGTH);
        zc->seqStore.maxNbLit = blockSize;

        zc->bufferedPolicy = zbuff;
        zc->inBuffSize = buffInSize;
        zc->inBuff = (char*)ZSTD_cwksp_reserve_buffer(ws, buffInSize);
        zc->outBuffSize = buffOutSize;
        zc->outBuff = (char*)ZSTD_cwksp_reserve_buffer(ws, buffOutSize);

        /* ldm bucketOffsets table */
        if (params->ldmParams.enableLdm == ZSTD_ps_enable) {
            /* TODO: avoid memset? */
            size_t const numBuckets =
                  ((size_t)1) << (params->ldmParams.hashLog -
                                  params->ldmParams.bucketSizeLog);
            zc->ldmState.bucketOffsets = ZSTD_cwksp_reserve_buffer(ws, numBuckets);
            ZSTD_memset(zc->ldmState.bucketOffsets, 0, numBuckets);
        }

        /* sequences storage */
        ZSTD_referenceExternalSequences(zc, NULL, 0);
        zc->seqStore.maxNbSeq = maxNbSeq;
        zc->seqStore.llCode = ZSTD_cwksp_reserve_buffer(ws, maxNbSeq * sizeof(BYTE));
        zc->seqStore.mlCode = ZSTD_cwksp_reserve_buffer(ws, maxNbSeq * sizeof(BYTE));
        zc->seqStore.ofCode = ZSTD_cwksp_reserve_buffer(ws, maxNbSeq * sizeof(BYTE));

        DEBUGLOG(3, "wksp: finished allocating, %zd bytes remain available", ZSTD_cwksp_available_space(ws));
        assert(ZSTD_cwksp_estimated_space_within_bounds(ws, neededSpace));

        zc->initialized = 1;

        return 0;
    }
}

/* ZSTD_invalidateRepCodes() :
 * ensures next compression will not use repcodes from previous block.
 * Note : only works with regular variant;
 *        do not use with extDict variant ! */
void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx) {
    ZSTD_compressedBlockState_t* const prevCBlock = cctx->blockState.prevCBlock;
    ZSTD_rust_invalidateRepCodes(prevCBlock->rep);
    assert(!ZSTD_window_hasExtDict(cctx->blockState.matchState.window));
}

static int ZSTD_shouldAttachDict(const ZSTD_CDict* cdict,
                                 const ZSTD_CCtx_params* params,
                                 U64 pledgedSrcSize)
{
    return ZSTD_rust_params_shouldAttachDict(
            cdict->matchState.cParams.strategy,
            cdict->matchState.dedicatedDictSearch,
            pledgedSrcSize,
            (int)params->attachDictPref,
            params->forceWindow);
}

static size_t
ZSTD_resetCCtx_byAttachingCDict(ZSTD_CCtx* cctx,
                        const ZSTD_CDict* cdict,
                        ZSTD_CCtx_params params,
                        U64 pledgedSrcSize,
                        ZSTD_buffered_policy_e zbuff)
{
    DEBUGLOG(4, "ZSTD_resetCCtx_byAttachingCDict() pledgedSrcSize=%llu",
                (unsigned long long)pledgedSrcSize);
    {
        ZSTD_compressionParameters adjusted_cdict_cParams = cdict->matchState.cParams;
        unsigned const windowLog = params.cParams.windowLog;
        assert(windowLog != 0);
        /* Resize working context table params for input only, since the dict
         * has its own tables. */
        /* pledgedSrcSize == 0 means 0! */

        if (cdict->matchState.dedicatedDictSearch) {
            ZSTD_dedicatedDictSearch_revertCParams(&adjusted_cdict_cParams);
        }

        params.cParams = ZSTD_adjustCParams_internal(adjusted_cdict_cParams, pledgedSrcSize,
                                                     cdict->dictContentSize, ZSTD_cpm_attachDict,
                                                     params.useRowMatchFinder);
        params.cParams.windowLog = windowLog;
        params.useRowMatchFinder = cdict->useRowMatchFinder;    /* cdict overrides */
        FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, &params, pledgedSrcSize,
                                                 /* loadedDictSize */ 0,
                                                 ZSTDcrp_makeClean, zbuff), "");
        assert(cctx->appliedParams.cParams.strategy == adjusted_cdict_cParams.strategy);
    }

    {   const U32 cdictEnd = (U32)( cdict->matchState.window.nextSrc
                                  - cdict->matchState.window.base);
        const U32 cdictLen = cdictEnd - cdict->matchState.window.dictLimit;
        if (cdictLen == 0) {
            /* don't even attach dictionaries with no contents */
            DEBUGLOG(4, "skipping attaching empty dictionary");
        } else {
            DEBUGLOG(4, "attaching dictionary into context");
            cctx->blockState.matchState.dictMatchState = &cdict->matchState;

            /* prep working match state so dict matches never have negative indices
             * when they are translated to the working context's index space. */
            if (cctx->blockState.matchState.window.dictLimit < cdictEnd) {
                cctx->blockState.matchState.window.nextSrc =
                    cctx->blockState.matchState.window.base + cdictEnd;
                ZSTD_rust_windowClear(
                    (size_t)(cctx->blockState.matchState.window.nextSrc -
                             cctx->blockState.matchState.window.base),
                    &cctx->blockState.matchState.window.lowLimit,
                    &cctx->blockState.matchState.window.dictLimit);
            }
            /* loadedDictEnd is expressed within the referential of the active context */
            cctx->blockState.matchState.loadedDictEnd = cctx->blockState.matchState.window.dictLimit;
    }   }

    cctx->dictID = cdict->dictID;
    cctx->dictContentSize = cdict->dictContentSize;

    /* copy block state */
    ZSTD_memcpy(cctx->blockState.prevCBlock, &cdict->cBlockState, sizeof(cdict->cBlockState));

    return 0;
}

static void ZSTD_copyCDictTableIntoCCtx(U32* dst, U32 const* src, size_t tableSize,
                                        ZSTD_compressionParameters const* cParams) {
    ZSTD_STATIC_ASSERT(ZSTD_SHORT_CACHE_TAG_BITS == 8);
    ZSTD_rust_copyCDictTableIntoCCtx(dst, src, tableSize,
                                     ZSTD_CDictIndicesAreTagged(cParams));
}

static size_t ZSTD_resetCCtx_byCopyingCDict(ZSTD_CCtx* cctx,
                            const ZSTD_CDict* cdict,
                            ZSTD_CCtx_params params,
                            U64 pledgedSrcSize,
                            ZSTD_buffered_policy_e zbuff)
{
    const ZSTD_compressionParameters *cdict_cParams = &cdict->matchState.cParams;

    assert(!cdict->matchState.dedicatedDictSearch);
    DEBUGLOG(4, "ZSTD_resetCCtx_byCopyingCDict() pledgedSrcSize=%llu",
                (unsigned long long)pledgedSrcSize);

    {   unsigned const windowLog = params.cParams.windowLog;
        assert(windowLog != 0);
        /* Copy only compression parameters related to tables. */
        params.cParams = *cdict_cParams;
        params.cParams.windowLog = windowLog;
        params.useRowMatchFinder = cdict->useRowMatchFinder;
        FORWARD_IF_ERROR(ZSTD_resetCCtx_internal(cctx, &params, pledgedSrcSize,
                                                 /* loadedDictSize */ 0,
                                                 ZSTDcrp_leaveDirty, zbuff), "");
        assert(cctx->appliedParams.cParams.strategy == cdict_cParams->strategy);
        assert(cctx->appliedParams.cParams.hashLog == cdict_cParams->hashLog);
        assert(cctx->appliedParams.cParams.chainLog == cdict_cParams->chainLog);
    }

    ZSTD_cwksp_mark_tables_dirty(&cctx->workspace);
    assert(params.useRowMatchFinder != ZSTD_ps_auto);

    /* copy tables */
    {   size_t const chainSize = ZSTD_allocateChainTable(cdict_cParams->strategy, cdict->useRowMatchFinder, 0 /* DDS guaranteed disabled */)
                                                            ? ((size_t)1 << cdict_cParams->chainLog)
                                                            : 0;
        size_t const hSize =  (size_t)1 << cdict_cParams->hashLog;

        ZSTD_copyCDictTableIntoCCtx(cctx->blockState.matchState.hashTable,
                                cdict->matchState.hashTable,
                                hSize, cdict_cParams);

        /* Do not copy cdict's chainTable if cctx has parameters such that it would not use chainTable */
        if (ZSTD_allocateChainTable(cctx->appliedParams.cParams.strategy, cctx->appliedParams.useRowMatchFinder, 0 /* forDDSDict */)) {
            ZSTD_copyCDictTableIntoCCtx(cctx->blockState.matchState.chainTable,
                                    cdict->matchState.chainTable,
                                    chainSize, cdict_cParams);
        }
        /* copy tag table */
        if (ZSTD_rowMatchFinderUsed(cdict_cParams->strategy, cdict->useRowMatchFinder)) {
            size_t const tagTableSize = hSize;
            ZSTD_memcpy(cctx->blockState.matchState.tagTable,
                        cdict->matchState.tagTable,
                        tagTableSize);
            cctx->blockState.matchState.hashSalt = cdict->matchState.hashSalt;
        }
    }

    /* Zero the hashTable3, since the cdict never fills it */
    assert(cctx->blockState.matchState.hashLog3 <= 31);
    {   U32 const h3log = cctx->blockState.matchState.hashLog3;
        size_t const h3Size = h3log ? ((size_t)1 << h3log) : 0;
        assert(cdict->matchState.hashLog3 == 0);
        ZSTD_memset(cctx->blockState.matchState.hashTable3, 0, h3Size * sizeof(U32));
    }

    ZSTD_cwksp_mark_tables_clean(&cctx->workspace);

    /* copy dictionary offsets */
    {   ZSTD_MatchState_t const* srcMatchState = &cdict->matchState;
        ZSTD_MatchState_t* dstMatchState = &cctx->blockState.matchState;
        dstMatchState->window       = srcMatchState->window;
        dstMatchState->nextToUpdate = srcMatchState->nextToUpdate;
        dstMatchState->loadedDictEnd= srcMatchState->loadedDictEnd;
    }

    cctx->dictID = cdict->dictID;
    cctx->dictContentSize = cdict->dictContentSize;

    /* copy block state */
    ZSTD_memcpy(cctx->blockState.prevCBlock, &cdict->cBlockState, sizeof(cdict->cBlockState));

    return 0;
}

/* We have a choice between copying the dictionary context into the working
 * context, or referencing the dictionary context from the working context
 * in-place. We decide here which strategy to use. */
static size_t ZSTD_resetCCtx_usingCDict(ZSTD_CCtx* cctx,
                            const ZSTD_CDict* cdict,
                            const ZSTD_CCtx_params* params,
                            U64 pledgedSrcSize,
                            ZSTD_buffered_policy_e zbuff)
{

    DEBUGLOG(4, "ZSTD_resetCCtx_usingCDict (pledgedSrcSize=%u)",
                (unsigned)pledgedSrcSize);

    if (ZSTD_shouldAttachDict(cdict, params, pledgedSrcSize)) {
        return ZSTD_resetCCtx_byAttachingCDict(
            cctx, cdict, *params, pledgedSrcSize, zbuff);
    } else {
        return ZSTD_resetCCtx_byCopyingCDict(
            cctx, cdict, *params, pledgedSrcSize, zbuff);
    }
}

/*! ZSTD_copyCCtx_internal() :
 *  Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
 *  Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
 *  The "context", in this case, refers to the hash and chain tables,
 *  entropy tables, and dictionary references.
 * `windowLog` value is enforced if != 0, otherwise value is copied from srcCCtx.
 * @return : 0, or an error code */
static size_t ZSTD_copyCCtx_internal(ZSTD_CCtx* dstCCtx,
                            const ZSTD_CCtx* srcCCtx,
                            ZSTD_frameParameters fParams,
                            U64 pledgedSrcSize,
                            ZSTD_buffered_policy_e zbuff)
{
    RETURN_ERROR_IF(srcCCtx->stage!=ZSTDcs_init, stage_wrong,
                    "Can't copy a ctx that's not in init stage.");
    DEBUGLOG(5, "ZSTD_copyCCtx_internal");
    ZSTD_memcpy(&dstCCtx->customMem, &srcCCtx->customMem, sizeof(ZSTD_customMem));
    {   ZSTD_CCtx_params params = dstCCtx->requestedParams;
        /* Copy only compression parameters related to tables. */
        params.cParams = srcCCtx->appliedParams.cParams;
        assert(srcCCtx->appliedParams.useRowMatchFinder != ZSTD_ps_auto);
        assert(srcCCtx->appliedParams.postBlockSplitter != ZSTD_ps_auto);
        assert(srcCCtx->appliedParams.ldmParams.enableLdm != ZSTD_ps_auto);
        params.useRowMatchFinder = srcCCtx->appliedParams.useRowMatchFinder;
        params.postBlockSplitter = srcCCtx->appliedParams.postBlockSplitter;
        params.ldmParams = srcCCtx->appliedParams.ldmParams;
        params.fParams = fParams;
        params.maxBlockSize = srcCCtx->appliedParams.maxBlockSize;
        ZSTD_resetCCtx_internal(dstCCtx, &params, pledgedSrcSize,
                                /* loadedDictSize */ 0,
                                ZSTDcrp_leaveDirty, zbuff);
        assert(dstCCtx->appliedParams.cParams.windowLog == srcCCtx->appliedParams.cParams.windowLog);
        assert(dstCCtx->appliedParams.cParams.strategy == srcCCtx->appliedParams.cParams.strategy);
        assert(dstCCtx->appliedParams.cParams.hashLog == srcCCtx->appliedParams.cParams.hashLog);
        assert(dstCCtx->appliedParams.cParams.chainLog == srcCCtx->appliedParams.cParams.chainLog);
        assert(dstCCtx->blockState.matchState.hashLog3 == srcCCtx->blockState.matchState.hashLog3);
    }

    ZSTD_cwksp_mark_tables_dirty(&dstCCtx->workspace);

    /* copy tables */
    {   size_t const chainSize = ZSTD_allocateChainTable(srcCCtx->appliedParams.cParams.strategy,
                                                         srcCCtx->appliedParams.useRowMatchFinder,
                                                         0 /* forDDSDict */)
                                    ? ((size_t)1 << srcCCtx->appliedParams.cParams.chainLog)
                                    : 0;
        size_t const hSize =  (size_t)1 << srcCCtx->appliedParams.cParams.hashLog;
        U32 const h3log = srcCCtx->blockState.matchState.hashLog3;
        size_t const h3Size = h3log ? ((size_t)1 << h3log) : 0;

        ZSTD_memcpy(dstCCtx->blockState.matchState.hashTable,
               srcCCtx->blockState.matchState.hashTable,
               hSize * sizeof(U32));
        ZSTD_memcpy(dstCCtx->blockState.matchState.chainTable,
               srcCCtx->blockState.matchState.chainTable,
               chainSize * sizeof(U32));
        ZSTD_memcpy(dstCCtx->blockState.matchState.hashTable3,
               srcCCtx->blockState.matchState.hashTable3,
               h3Size * sizeof(U32));
    }

    ZSTD_cwksp_mark_tables_clean(&dstCCtx->workspace);

    /* copy dictionary offsets */
    {
        const ZSTD_MatchState_t* srcMatchState = &srcCCtx->blockState.matchState;
        ZSTD_MatchState_t* dstMatchState = &dstCCtx->blockState.matchState;
        dstMatchState->window       = srcMatchState->window;
        dstMatchState->nextToUpdate = srcMatchState->nextToUpdate;
        dstMatchState->loadedDictEnd= srcMatchState->loadedDictEnd;
    }
    dstCCtx->dictID = srcCCtx->dictID;
    dstCCtx->dictContentSize = srcCCtx->dictContentSize;

    /* copy block state */
    ZSTD_memcpy(dstCCtx->blockState.prevCBlock, srcCCtx->blockState.prevCBlock, sizeof(*srcCCtx->blockState.prevCBlock));

    return 0;
}

/*! ZSTD_copyCCtx() :
 *  Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
 *  Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
 *  pledgedSrcSize==0 means "unknown".
*   @return : 0, or an error code */
size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long long pledgedSrcSize)
{
    ZSTD_frameParameters fParams = { 1 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
    ZSTD_buffered_policy_e const zbuff = srcCCtx->bufferedPolicy;
    ZSTD_STATIC_ASSERT((U32)ZSTDb_buffered==1);
    if (pledgedSrcSize==0) pledgedSrcSize = ZSTD_CONTENTSIZE_UNKNOWN;
    fParams.contentSizeFlag = (pledgedSrcSize != ZSTD_CONTENTSIZE_UNKNOWN);

    return ZSTD_copyCCtx_internal(dstCCtx, srcCCtx,
                                fParams, pledgedSrcSize,
                                zbuff);
}


/*! ZSTD_reduceIndex() :
*   rescale all indexes to avoid future overflow (indexes are U32) */
static void ZSTD_reduceIndex (ZSTD_MatchState_t* ms, ZSTD_CCtx_params const* params, const U32 reducerValue)
{
    U32 const hSize = (U32)1 << params->cParams.hashLog;
    U32* chainTable = NULL;
    U32 chainSize = 0;
    U32* hashTable3 = NULL;
    U32 hashSize3 = 0;

    if (ZSTD_allocateChainTable(params->cParams.strategy, params->useRowMatchFinder, (U32)ms->dedicatedDictSearch)) {
        chainTable = ms->chainTable;
        chainSize = (U32)1 << params->cParams.chainLog;
    }

    if (ms->hashLog3) {
        hashTable3 = ms->hashTable3;
        hashSize3 = (U32)1 << ms->hashLog3;
    }

    ZSTD_rust_reduceIndex(ms->hashTable, hSize,
                          chainTable, chainSize,
                          hashTable3, hashSize3,
                          reducerValue,
                          params->cParams.strategy == ZSTD_btlazy2);
}


/*-*******************************************************
*  Block entropic compression
*********************************************************/

/* See doc/zstd_compression_format.md for detailed format description */

/* ZSTD_seqToCodes() lives in rust/src/zstd_compress_stats.rs. */

/* ZSTD_useTargetCBlockSize():
 * Returns if target compressed block size param is being used.
 * If used, compression will do best effort to make a compressed block size to be around targetCBlockSize.
 * Returns 1 if true, 0 otherwise. */
static int ZSTD_useTargetCBlockSize(const ZSTD_CCtx_params* cctxParams)
{
    DEBUGLOG(5, "ZSTD_useTargetCBlockSize (targetCBlockSize=%zu)", cctxParams->targetCBlockSize);
    return ZSTD_rust_useTargetCBlockSize(cctxParams);
}

/* ZSTD_blockSplitterEnabled():
 * Returns if block splitting param is being used
 * If used, compression will do best effort to split a block in order to improve compression ratio.
 * At the time this function is called, the parameter must be finalized.
 * Returns 1 if true, 0 otherwise. */
static int ZSTD_blockSplitterEnabled(ZSTD_CCtx_params* cctxParams)
{
    DEBUGLOG(5, "ZSTD_blockSplitterEnabled (postBlockSplitter=%d)", cctxParams->postBlockSplitter);
    return ZSTD_rust_blockSplitterEnabled(cctxParams);
}

/* ZSTD_buildSequencesStatistics() and the ZSTD_entropyCompressSeqStore*()
 * implementations live in rust/src/zstd_compress_stats.rs.  The wrappers
 * below keep the original signatures and extract the only two
 * ZSTD_CCtx_params fields those paths read. */

MEM_STATIC size_t
ZSTD_entropyCompressSeqStore_internal(
                              void* dst, size_t dstCapacity,
                        const void* literals, size_t litSize,
                        const SeqStore_t* seqStorePtr,
                        const ZSTD_entropyCTables_t* prevEntropy,
                              ZSTD_entropyCTables_t* nextEntropy,
                        const ZSTD_CCtx_params* cctxParams,
                              void* entropyWorkspace, size_t entropyWkspSize,
                        const int bmi2)
{
    return ZSTD_rust_entropyCompressSeqStore_internal(
                dst, dstCapacity,
                literals, litSize,
                seqStorePtr, prevEntropy, nextEntropy,
                (int)cctxParams->cParams.strategy,
                ZSTD_literalsCompressionIsDisabled(cctxParams),
                entropyWorkspace, entropyWkspSize, bmi2);
}

/* ZSTD_selectBlockCompressor() :
 * Not static, but internal use only (used by long distance matcher)
 * assumption : strat is a valid strategy */
ZSTD_BlockCompressor_f ZSTD_selectBlockCompressor(ZSTD_strategy strat, ZSTD_ParamSwitch_e useRowMatchFinder, ZSTD_dictMode_e dictMode)
{
    static const ZSTD_BlockCompressor_f blockCompressor[4][ZSTD_STRATEGY_MAX+1] = {
        { ZSTD_compressBlock_fast  /* default for 0 */,
          ZSTD_compressBlock_fast,
          ZSTD_COMPRESSBLOCK_DOUBLEFAST,
          ZSTD_COMPRESSBLOCK_GREEDY,
          ZSTD_COMPRESSBLOCK_LAZY,
          ZSTD_COMPRESSBLOCK_LAZY2,
          ZSTD_COMPRESSBLOCK_BTLAZY2,
          ZSTD_COMPRESSBLOCK_BTOPT,
          ZSTD_COMPRESSBLOCK_BTULTRA,
          ZSTD_COMPRESSBLOCK_BTULTRA2
        },
        { ZSTD_compressBlock_fast_extDict  /* default for 0 */,
          ZSTD_compressBlock_fast_extDict,
          ZSTD_COMPRESSBLOCK_DOUBLEFAST_EXTDICT,
          ZSTD_COMPRESSBLOCK_GREEDY_EXTDICT,
          ZSTD_COMPRESSBLOCK_LAZY_EXTDICT,
          ZSTD_COMPRESSBLOCK_LAZY2_EXTDICT,
          ZSTD_COMPRESSBLOCK_BTLAZY2_EXTDICT,
          ZSTD_COMPRESSBLOCK_BTOPT_EXTDICT,
          ZSTD_COMPRESSBLOCK_BTULTRA_EXTDICT,
          ZSTD_COMPRESSBLOCK_BTULTRA_EXTDICT
        },
        { ZSTD_compressBlock_fast_dictMatchState  /* default for 0 */,
          ZSTD_compressBlock_fast_dictMatchState,
          ZSTD_COMPRESSBLOCK_DOUBLEFAST_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_GREEDY_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_LAZY_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_LAZY2_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_BTLAZY2_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_BTOPT_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_BTULTRA_DICTMATCHSTATE,
          ZSTD_COMPRESSBLOCK_BTULTRA_DICTMATCHSTATE
        },
        { NULL  /* default for 0 */,
          NULL,
          NULL,
          ZSTD_COMPRESSBLOCK_GREEDY_DEDICATEDDICTSEARCH,
          ZSTD_COMPRESSBLOCK_LAZY_DEDICATEDDICTSEARCH,
          ZSTD_COMPRESSBLOCK_LAZY2_DEDICATEDDICTSEARCH,
          NULL,
          NULL,
          NULL,
          NULL }
    };
    ZSTD_BlockCompressor_f selectedCompressor;
    int selectedCompressorIndex;
    ZSTD_STATIC_ASSERT((unsigned)ZSTD_fast == 1);

    assert(ZSTD_cParam_withinBounds(ZSTD_c_strategy, (int)strat));
    DEBUGLOG(5, "Selected block compressor: dictMode=%d strat=%d rowMatchfinder=%d", (int)dictMode, (int)strat, (int)useRowMatchFinder);
    selectedCompressorIndex = ZSTD_rust_params_selectBlockCompressor(
            (int)strat, (int)useRowMatchFinder);
    if (selectedCompressorIndex < 3) {
        static const ZSTD_BlockCompressor_f rowBasedBlockCompressors[4][3] = {
            {
                ZSTD_COMPRESSBLOCK_GREEDY_ROW,
                ZSTD_COMPRESSBLOCK_LAZY_ROW,
                ZSTD_COMPRESSBLOCK_LAZY2_ROW
            },
            {
                ZSTD_COMPRESSBLOCK_GREEDY_EXTDICT_ROW,
                ZSTD_COMPRESSBLOCK_LAZY_EXTDICT_ROW,
                ZSTD_COMPRESSBLOCK_LAZY2_EXTDICT_ROW
            },
            {
                ZSTD_COMPRESSBLOCK_GREEDY_DICTMATCHSTATE_ROW,
                ZSTD_COMPRESSBLOCK_LAZY_DICTMATCHSTATE_ROW,
                ZSTD_COMPRESSBLOCK_LAZY2_DICTMATCHSTATE_ROW
            },
            {
                ZSTD_COMPRESSBLOCK_GREEDY_DEDICATEDDICTSEARCH_ROW,
                ZSTD_COMPRESSBLOCK_LAZY_DEDICATEDDICTSEARCH_ROW,
                ZSTD_COMPRESSBLOCK_LAZY2_DEDICATEDDICTSEARCH_ROW
            }
        };
        DEBUGLOG(5, "Selecting a row-based matchfinder");
        assert(useRowMatchFinder != ZSTD_ps_auto);
        selectedCompressor = rowBasedBlockCompressors[(int)dictMode][selectedCompressorIndex];
    } else {
        selectedCompressor = blockCompressor[(int)dictMode][selectedCompressorIndex - 3];
    }
    assert(selectedCompressor != NULL);
    return selectedCompressor;
}

static void ZSTD_storeLastLiterals(SeqStore_t* seqStorePtr,
                                   const BYTE* anchor, size_t lastLLSize)
{
    ZSTD_rust_storeLastLiterals(seqStorePtr, anchor, lastLLSize);
}

void ZSTD_resetSeqStore(SeqStore_t* ssPtr)
{
    ZSTD_rust_resetSeqStore(ssPtr);
}

/* ZSTD_postProcessSequenceProducerResult() :
 * Validates and post-processes sequences obtained through the external matchfinder API:
 *   - Checks whether nbExternalSeqs represents an error condition.
 *   - Appends a block delimiter to outSeqs if one is not already present.
 *     See zstd.h for context regarding block delimiters.
 * Returns the number of sequences after post-processing, or an error code. */
static size_t ZSTD_postProcessSequenceProducerResult(
    ZSTD_Sequence* outSeqs, size_t nbExternalSeqs, size_t outSeqsCapacity, size_t srcSize
) {
    return ZSTD_rust_postProcessSequenceProducerResult(
        outSeqs, nbExternalSeqs, outSeqsCapacity, srcSize);
}

/* ZSTD_fastSequenceLengthSum() :
 * Returns sum(litLen) + sum(matchLen) + lastLits for *seqBuf*.
 * Similar to another function in zstd_compress.c (determine_blockSize),
 * except it doesn't check for a block delimiter to end summation.
 * Removing the early exit allows the compiler to auto-vectorize (https://godbolt.org/z/cY1cajz9P).
 * This function can be deleted and replaced by determine_blockSize after we resolve issue #3456. */
static size_t ZSTD_fastSequenceLengthSum(ZSTD_Sequence const* seqBuf, size_t seqBufSize) {
    return ZSTD_rust_fastSequenceLengthSum(seqBuf, seqBufSize);
}

/**
 * Function to validate sequences produced by a block compressor.
 */
static void ZSTD_validateSeqStore(const SeqStore_t* seqStore, const ZSTD_compressionParameters* cParams)
{
#if DEBUGLEVEL >= 1
    ZSTD_rust_validateSeqStore(seqStore, (U32)cParams->minMatch);
#else
    (void)seqStore;
    (void)cParams;
#endif
}

static size_t
ZSTD_transferSequences_wBlockDelim(ZSTD_CCtx* cctx,
                                   ZSTD_SequencePosition* seqPos,
                             const ZSTD_Sequence* const inSeqs, size_t inSeqsSize,
                             const void* src, size_t blockSize,
                                   ZSTD_ParamSwitch_e externalRepSearch);

typedef enum { ZSTDbss_compress, ZSTDbss_noCompress } ZSTD_BuildSeqStore_e;

static size_t ZSTD_buildSeqStore(ZSTD_CCtx* zc, const void* src, size_t srcSize)
{
    ZSTD_MatchState_t* const ms = &zc->blockState.matchState;
    DEBUGLOG(5, "ZSTD_buildSeqStore (srcSize=%zu)", srcSize);
    assert(srcSize <= ZSTD_BLOCKSIZE_MAX);
    /* Assert that we have correctly flushed the ctx params into the ms's copy */
    ZSTD_assertEqualCParams(zc->appliedParams.cParams, ms->cParams);
    /* TODO: See 3090. We reduced MIN_CBLOCK_SIZE from 3 to 2 so to compensate we are adding
     * additional 1. We need to revisit and change this logic to be more consistent */
    if (srcSize < MIN_CBLOCK_SIZE+ZSTD_blockHeaderSize+1+1) {
        if (zc->appliedParams.cParams.strategy >= ZSTD_btopt) {
            ZSTD_ldm_skipRawSeqStoreBytes(&zc->externSeqStore, srcSize);
        } else {
            ZSTD_ldm_skipSequences(&zc->externSeqStore, srcSize, zc->appliedParams.cParams.minMatch);
        }
        return ZSTDbss_noCompress; /* don't even attempt compression below a certain srcSize */
    }
    ZSTD_resetSeqStore(&(zc->seqStore));
    /* required for optimal parser to read stats from dictionary */
    ms->opt.symbolCosts = &zc->blockState.prevCBlock->entropy;
    /* tell the optimal parser how we expect to compress literals */
    ms->opt.literalCompressionMode = zc->appliedParams.literalCompressionMode;
    /* a gap between an attached dict and the current window is not safe,
     * they must remain adjacent,
     * and when that stops being the case, the dict must be unset */
    assert(ms->dictMatchState == NULL || ms->loadedDictEnd == ms->window.dictLimit);

    /* limited update after a very long match */
    {   const BYTE* const base = ms->window.base;
        const BYTE* const istart = (const BYTE*)src;
        const U32 curr = (U32)(istart-base);
        if (sizeof(ptrdiff_t)==8) assert(istart - base < (ptrdiff_t)(U32)(-1));   /* ensure no overflow */
        if (curr > ms->nextToUpdate + 384)
            ms->nextToUpdate = curr - MIN(192, (U32)(curr - ms->nextToUpdate - 384));
    }

    /* select and store sequences */
    {   ZSTD_dictMode_e const dictMode = ZSTD_matchState_dictMode(ms);
        size_t lastLLSize;
        {   int i;
            for (i = 0; i < ZSTD_REP_NUM; ++i)
                zc->blockState.nextCBlock->rep[i] = zc->blockState.prevCBlock->rep[i];
        }
        if (zc->externSeqStore.pos < zc->externSeqStore.size) {
            assert(zc->appliedParams.ldmParams.enableLdm == ZSTD_ps_disable);

            /* External matchfinder + LDM is technically possible, just not implemented yet.
             * We need to revisit soon and implement it. */
            RETURN_ERROR_IF(
                ZSTD_hasExtSeqProd(&zc->appliedParams),
                parameter_combination_unsupported,
                "Long-distance matching with external sequence producer enabled is not currently supported."
            );

            /* Updates ldmSeqStore.pos */
            lastLLSize =
                ZSTD_ldm_blockCompress(&zc->externSeqStore,
                                       ms, &zc->seqStore,
                                       zc->blockState.nextCBlock->rep,
                                       zc->appliedParams.useRowMatchFinder,
                                       src, srcSize);
            assert(zc->externSeqStore.pos <= zc->externSeqStore.size);
        } else if (zc->appliedParams.ldmParams.enableLdm == ZSTD_ps_enable) {
            RawSeqStore_t ldmSeqStore = kNullRawSeqStore;

            /* External matchfinder + LDM is technically possible, just not implemented yet.
             * We need to revisit soon and implement it. */
            RETURN_ERROR_IF(
                ZSTD_hasExtSeqProd(&zc->appliedParams),
                parameter_combination_unsupported,
                "Long-distance matching with external sequence producer enabled is not currently supported."
            );

            ldmSeqStore.seq = zc->ldmSequences;
            ldmSeqStore.capacity = zc->maxNbLdmSequences;
            /* Updates ldmSeqStore.size */
            FORWARD_IF_ERROR(ZSTD_ldm_generateSequences(&zc->ldmState, &ldmSeqStore,
                                               &zc->appliedParams.ldmParams,
                                               src, srcSize), "");
            /* Updates ldmSeqStore.pos */
            lastLLSize =
                ZSTD_ldm_blockCompress(&ldmSeqStore,
                                       ms, &zc->seqStore,
                                       zc->blockState.nextCBlock->rep,
                                       zc->appliedParams.useRowMatchFinder,
                                       src, srcSize);
            assert(ldmSeqStore.pos == ldmSeqStore.size);
        } else if (ZSTD_hasExtSeqProd(&zc->appliedParams)) {
            assert(
                zc->extSeqBufCapacity >= ZSTD_sequenceBound(srcSize)
            );
            assert(zc->appliedParams.extSeqProdFunc != NULL);

            {   U32 const windowSize = (U32)1 << zc->appliedParams.cParams.windowLog;

                size_t const nbExternalSeqs = (zc->appliedParams.extSeqProdFunc)(
                    zc->appliedParams.extSeqProdState,
                    zc->extSeqBuf,
                    zc->extSeqBufCapacity,
                    src, srcSize,
                    NULL, 0,  /* dict and dictSize, currently not supported */
                    zc->appliedParams.compressionLevel,
                    windowSize
                );

                size_t const nbPostProcessedSeqs = ZSTD_postProcessSequenceProducerResult(
                    zc->extSeqBuf,
                    nbExternalSeqs,
                    zc->extSeqBufCapacity,
                    srcSize
                );

                /* Return early if there is no error, since we don't need to worry about last literals */
                if (!ZSTD_isError(nbPostProcessedSeqs)) {
                    ZSTD_SequencePosition seqPos = {0,0,0};
                    size_t const seqLenSum = ZSTD_fastSequenceLengthSum(zc->extSeqBuf, nbPostProcessedSeqs);
                    RETURN_ERROR_IF(seqLenSum > srcSize, externalSequences_invalid, "External sequences imply too large a block!");
                    FORWARD_IF_ERROR(
                        ZSTD_transferSequences_wBlockDelim(
                            zc, &seqPos,
                            zc->extSeqBuf, nbPostProcessedSeqs,
                            src, srcSize,
                            zc->appliedParams.searchForExternalRepcodes
                        ),
                        "Failed to copy external sequences to seqStore!"
                    );
                    ms->ldmSeqStore = NULL;
                    DEBUGLOG(5, "Copied %lu sequences from external sequence producer to internal seqStore.", (unsigned long)nbExternalSeqs);
                    return ZSTDbss_compress;
                }

                /* Propagate the error if fallback is disabled */
                if (!zc->appliedParams.enableMatchFinderFallback) {
                    return nbPostProcessedSeqs;
                }

                /* Fallback to software matchfinder */
                {   ZSTD_BlockCompressor_f const blockCompressor =
                        ZSTD_selectBlockCompressor(
                            zc->appliedParams.cParams.strategy,
                            zc->appliedParams.useRowMatchFinder,
                            dictMode);
                    ms->ldmSeqStore = NULL;
                    DEBUGLOG(
                        5,
                        "External sequence producer returned error code %lu. Falling back to internal parser.",
                        (unsigned long)nbExternalSeqs
                    );
                    lastLLSize = blockCompressor(ms, &zc->seqStore, zc->blockState.nextCBlock->rep, src, srcSize);
            }   }
        } else {   /* not long range mode and no external matchfinder */
            ZSTD_BlockCompressor_f const blockCompressor = ZSTD_selectBlockCompressor(
                    zc->appliedParams.cParams.strategy,
                    zc->appliedParams.useRowMatchFinder,
                    dictMode);
            ms->ldmSeqStore = NULL;
            lastLLSize = blockCompressor(ms, &zc->seqStore, zc->blockState.nextCBlock->rep, src, srcSize);
        }
        {   const BYTE* const lastLiterals = (const BYTE*)src + srcSize - lastLLSize;
            ZSTD_storeLastLiterals(&zc->seqStore, lastLiterals, lastLLSize);
    }   }
    ZSTD_validateSeqStore(&zc->seqStore, &zc->appliedParams.cParams);
    return ZSTDbss_compress;
}

/* ZSTD_sequenceBound() lives in rust/src/zstd_compress_api.rs. */

size_t ZSTD_generateSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
                              size_t outSeqsSize, const void* src, size_t srcSize)
{
    const size_t dstCapacity = ZSTD_compressBound(srcSize);
    void* dst; /* Make C90 happy. */
    SeqCollector seqCollector;
    {
        int targetCBlockSize;
        FORWARD_IF_ERROR(ZSTD_CCtx_getParameter(zc, ZSTD_c_targetCBlockSize, &targetCBlockSize), "");
        RETURN_ERROR_IF(targetCBlockSize != 0, parameter_unsupported, "targetCBlockSize != 0");
    }
    {
        int nbWorkers;
        FORWARD_IF_ERROR(ZSTD_CCtx_getParameter(zc, ZSTD_c_nbWorkers, &nbWorkers), "");
        RETURN_ERROR_IF(nbWorkers != 0, parameter_unsupported, "nbWorkers != 0");
    }

    dst = ZSTD_customMalloc(dstCapacity, ZSTD_defaultCMem);
    RETURN_ERROR_IF(dst == NULL, memory_allocation, "NULL pointer!");

    seqCollector.collectSequences = 1;
    seqCollector.seqStart = outSeqs;
    seqCollector.seqIndex = 0;
    seqCollector.maxSequences = outSeqsSize;
    zc->seqCollector = seqCollector;

    {
        const size_t ret = ZSTD_compress2(zc, dst, dstCapacity, src, srcSize);
        ZSTD_customFree(dst, ZSTD_defaultCMem);
        FORWARD_IF_ERROR(ret, "ZSTD_compress2 failed");
    }
    assert(zc->seqCollector.seqIndex <= ZSTD_sequenceBound(srcSize));
    return zc->seqCollector.seqIndex;
}

/* ZSTD_mergeBlockDelimiters() lives in rust/src/zstd_compress_api.rs. */

static void
ZSTD_blockState_confirmRepcodesAndEntropyTables(ZSTD_blockState_t* const bs)
{
    ZSTD_rust_confirmRepcodesAndEntropyTables(
            &bs->prevCBlock, &bs->nextCBlock);
}

/** ZSTD_buildBlockEntropyStats() :
 *  Builds entropy for the block.
 *  Requires workspace size ENTROPY_WORKSPACE_SIZE
 * @return : 0 on success, or an error code
 *  Note : also employed in superblock
 *
 *  The implementation, together with its literals/sequences/dummy helpers,
 *  lives in rust/src/zstd_compress_stats.rs.
 */
size_t ZSTD_buildBlockEntropyStats(
            const SeqStore_t* seqStorePtr,
            const ZSTD_entropyCTables_t* prevEntropy,
                  ZSTD_entropyCTables_t* nextEntropy,
            const ZSTD_CCtx_params* cctxParams,
                  ZSTD_entropyCTablesMetadata_t* entropyMetadata,
                  void* workspace, size_t wkspSize)
{
    return ZSTD_rust_buildBlockEntropyStats(
                seqStorePtr, prevEntropy, nextEntropy,
                (int)cctxParams->cParams.strategy,
                ZSTD_literalsCompressionIsDisabled(cctxParams),
                entropyMetadata,
                workspace, wkspSize);
}

/* Base recursive function.
 * Populates a table with intra-block partition indices that can improve compression ratio.
 *
 * @return: number of splits made (which equals the size of the partition table - 1).
 */
static size_t ZSTD_deriveBlockSplits(ZSTD_CCtx* zc, U32 partitions[], U32 nbSeq)
{
    return ZSTD_rust_deriveBlockSplits(
            partitions, nbSeq,
            &zc->seqStore,
            &zc->blockSplitCtx.fullSeqStoreChunk,
            &zc->blockSplitCtx.firstHalfSeqStore,
            &zc->blockSplitCtx.secondHalfSeqStore,
            &zc->blockState.prevCBlock->entropy,
            &zc->blockState.nextCBlock->entropy,
            (int)zc->appliedParams.cParams.strategy,
            ZSTD_literalsCompressionIsDisabled(&zc->appliedParams),
            &zc->blockSplitCtx.entropyMetadata,
            zc->tmpWorkspace,
            zc->tmpWkspSize);
}

/* ZSTD_compressBlock_splitBlock():
 * Attempts to split a given block into multiple blocks to improve compression ratio.
 *
 * Returns combined size of all blocks (which includes headers), or a ZSTD error code.
 */
static size_t
ZSTD_compressBlock_splitBlock_internal(ZSTD_CCtx* zc,
                                    void* dst, size_t dstCapacity,
                              const void* src, size_t blockSize,
                                    U32 lastBlock, U32 nbSeq)
{
    ZSTD_rust_splitBlockState state;
    U32* const partitions = zc->blockSplitCtx.partitions; /* splits plus the terminal boundary */
    size_t const numSplits = ZSTD_deriveBlockSplits(zc, partitions, nbSeq);

    DEBUGLOG(5, "ZSTD_compressBlock_splitBlock_internal (dstCapacity=%u, dictLimit=%u, nextToUpdate=%u)",
                (unsigned)dstCapacity, (unsigned)zc->blockState.matchState.window.dictLimit,
                (unsigned)zc->blockState.matchState.nextToUpdate);
    state.seqStore = &zc->seqStore;
    state.partitions = partitions;
    state.nextSeqStore = &zc->blockSplitCtx.nextSeqStore;
    state.currSeqStore = &zc->blockSplitCtx.currSeqStore;
    state.prevCBlock = &zc->blockState.prevCBlock;
    state.nextCBlock = &zc->blockState.nextCBlock;
    state.tmpWorkspace = zc->tmpWorkspace;
    state.tmpWkspSize = zc->tmpWkspSize;
    state.seqCollector = &zc->seqCollector;
    state.blockSizeMax = zc->blockSizeMax;
    state.strategy = (int)zc->appliedParams.cParams.strategy;
    state.disableLiteralCompression = ZSTD_literalsCompressionIsDisabled(&zc->appliedParams);
    state.bmi2 = zc->bmi2;
    state.isFirstBlock = zc->isFirstBlock;
    return ZSTD_rust_compressBlockSplit(
            &state, dst, dstCapacity, src, blockSize, lastBlock, numSplits);
}

static size_t
ZSTD_compressBlock_splitBlock(ZSTD_CCtx* zc,
                              void* dst, size_t dstCapacity,
                              const void* src, size_t srcSize, U32 lastBlock)
{
    U32 nbSeq;
    size_t cSize;
    DEBUGLOG(5, "ZSTD_compressBlock_splitBlock");
    assert(zc->appliedParams.postBlockSplitter == ZSTD_ps_enable);

    {   const size_t bss = ZSTD_buildSeqStore(zc, src, srcSize);
        FORWARD_IF_ERROR(bss, "ZSTD_buildSeqStore failed");
        if (bss == ZSTDbss_noCompress) {
            if (zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
                zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;
            RETURN_ERROR_IF(zc->seqCollector.collectSequences, sequenceProducer_failed, "Uncompressible block");
            cSize = ZSTD_rust_noCompressBlock(dst, dstCapacity, src, srcSize, lastBlock);
            FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed");
            DEBUGLOG(5, "ZSTD_compressBlock_splitBlock: Nocompress block");
            return cSize;
        }
        nbSeq = (U32)(zc->seqStore.sequences - zc->seqStore.sequencesStart);
    }

    cSize = ZSTD_compressBlock_splitBlock_internal(zc, dst, dstCapacity, src, srcSize, lastBlock, nbSeq);
    FORWARD_IF_ERROR(cSize, "Splitting blocks failed!");
    return cSize;
}

static size_t
ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
                            void* dst, size_t dstCapacity,
                            const void* src, size_t srcSize, U32 frame)
{
    ZSTD_rust_blockInternalState state;
    DEBUGLOG(5, "ZSTD_compressBlock_internal (dstCapacity=%u, dictLimit=%u, nextToUpdate=%u)",
                (unsigned)dstCapacity, (unsigned)zc->blockState.matchState.window.dictLimit,
                (unsigned)zc->blockState.matchState.nextToUpdate);

    {   const size_t bss = ZSTD_buildSeqStore(zc, src, srcSize);
        FORWARD_IF_ERROR(bss, "ZSTD_buildSeqStore failed");
        if (bss == ZSTDbss_noCompress) {
            RETURN_ERROR_IF(zc->seqCollector.collectSequences, sequenceProducer_failed, "Uncompressible block");
            if (zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
                zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;
            return 0;
        }
    }

    state.seqStore = &zc->seqStore;
    state.prevCBlock = &zc->blockState.prevCBlock;
    state.nextCBlock = &zc->blockState.nextCBlock;
    state.tmpWorkspace = zc->tmpWorkspace;
    state.tmpWkspSize = zc->tmpWkspSize;
    state.seqCollector = &zc->seqCollector;
    state.strategy = (int)zc->appliedParams.cParams.strategy;
    state.disableLiteralCompression = ZSTD_literalsCompressionIsDisabled(&zc->appliedParams);
    state.bmi2 = zc->bmi2;
    state.isFirstBlock = zc->isFirstBlock;
    return ZSTD_rust_compressBlockInternal(
            &state, dst, dstCapacity, src, srcSize, frame);
}

static size_t ZSTD_compressBlock_targetCBlockSize(ZSTD_CCtx* zc,
                               void* dst, size_t dstCapacity,
                               const void* src, size_t srcSize,
                               U32 lastBlock)
{
    size_t cSize = 0;
    const size_t bss = ZSTD_buildSeqStore(zc, src, srcSize);
    DEBUGLOG(5, "ZSTD_compressBlock_targetCBlockSize (dstCapacity=%u, dictLimit=%u, nextToUpdate=%u, srcSize=%zu)",
                (unsigned)dstCapacity, (unsigned)zc->blockState.matchState.window.dictLimit, (unsigned)zc->blockState.matchState.nextToUpdate, srcSize);
    FORWARD_IF_ERROR(bss, "ZSTD_buildSeqStore failed");

    {   ZSTD_rust_targetCBlockSizeState state;
        state.seqStore = &zc->seqStore;
        state.prevCBlock = &zc->blockState.prevCBlock;
        state.nextCBlock = &zc->blockState.nextCBlock;
        state.tmpWorkspace = zc->tmpWorkspace;
        state.tmpWkspSize = zc->tmpWkspSize;
        state.strategy = (int)zc->appliedParams.cParams.strategy;
        state.disableLiteralCompression = ZSTD_literalsCompressionIsDisabled(&zc->appliedParams);
        state.bmi2 = zc->bmi2;
        state.windowLog = zc->appliedParams.cParams.windowLog;
        state.targetCBlockSize = zc->appliedParams.targetCBlockSize;
        state.isFirstBlock = zc->isFirstBlock;
        cSize = ZSTD_rust_compressBlockTargetCBlockSize(
                &state, dst, dstCapacity, src, srcSize, (int)bss, lastBlock);
    }
    FORWARD_IF_ERROR(cSize, "ZSTD_compressBlock_targetCBlockSize_body failed");

    if (zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
        zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;

    return cSize;
}

static void ZSTD_overflowCorrectIfNeeded(ZSTD_MatchState_t* ms,
                                         ZSTD_cwksp* ws,
                                         ZSTD_CCtx_params const* params,
                                         void const* ip,
                                         void const* iend)
{
    U32 const cycleLog = ZSTD_cycleLog(params->cParams.chainLog, params->cParams.strategy);
    U32 const maxDist = (U32)1 << params->cParams.windowLog;
    if (ZSTD_window_needOverflowCorrection(ms->window, cycleLog, maxDist, ms->loadedDictEnd, ip, iend)) {
        U32 const correction = ZSTD_window_correctOverflow(&ms->window, cycleLog, maxDist, ip);
        ZSTD_STATIC_ASSERT(ZSTD_CHAINLOG_MAX <= 30);
        ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX_32 <= 30);
        ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX <= 31);
        ZSTD_cwksp_mark_tables_dirty(ws);
        ZSTD_reduceIndex(ms, params, correction);
        ZSTD_cwksp_mark_tables_clean(ws);
        if (ms->nextToUpdate < correction) ms->nextToUpdate = 0;
        else ms->nextToUpdate -= correction;
        /* invalidate dictionaries on overflow correction */
        ms->loadedDictEnd = 0;
        ms->dictMatchState = NULL;
    }
}

#include "zstd_preSplit.h"

static void ZSTD_rust_frameChunk_prepareBlock(void* context,
                                               const void* src,
                                               size_t blockSize)
{
    ZSTD_CCtx* const cctx = (ZSTD_CCtx*)context;
    ZSTD_MatchState_t* const ms = &cctx->blockState.matchState;
    U32 const maxDist = (U32)1 << cctx->appliedParams.cParams.windowLog;

    ZSTD_overflowCorrectIfNeeded(
            ms, &cctx->workspace, &cctx->appliedParams,
            src, (const BYTE*)src + blockSize);
    ZSTD_checkDictValidity(
            &ms->window, (const BYTE*)src + blockSize, maxDist,
            &ms->loadedDictEnd, &ms->dictMatchState);
    ZSTD_window_enforceMaxDist(
            &ms->window, src, maxDist,
            &ms->loadedDictEnd, &ms->dictMatchState);

    /* Ensure hash/chain table insertion resumes no sooner than lowlimit. */
    if (ms->nextToUpdate < ms->window.lowLimit)
        ms->nextToUpdate = ms->window.lowLimit;
}

static size_t ZSTD_rust_frameChunk_compressTarget(
        void* context, void* dst, size_t dstCapacity,
        const void* src, size_t srcSize, U32 lastBlock)
{
    return ZSTD_compressBlock_targetCBlockSize(
            (ZSTD_CCtx*)context, dst, dstCapacity, src, srcSize, lastBlock);
}

static size_t ZSTD_rust_frameChunk_compressSplit(
        void* context, void* dst, size_t dstCapacity,
        const void* src, size_t srcSize, U32 lastBlock)
{
    return ZSTD_compressBlock_splitBlock(
            (ZSTD_CCtx*)context, dst, dstCapacity, src, srcSize, lastBlock);
}

static size_t ZSTD_rust_frameChunk_compressInternal(
        void* context, void* dst, size_t dstCapacity,
        const void* src, size_t srcSize, U32 lastBlock)
{
    (void)lastBlock;
    return ZSTD_compressBlock_internal(
            (ZSTD_CCtx*)context, dst, dstCapacity, src, srcSize,
            1 /* frame */);
}

static void ZSTD_rust_frameChunk_updateChecksum(
        void* state, const void* src, size_t srcSize)
{
    (void)XXH64_update((XXH64_state_t*)state, src, srcSize);
}

/*! ZSTD_compress_frameChunk() :
*   Compress a chunk of data into one or multiple blocks.
*   All blocks will be terminated, all input will be consumed.
*   Function will issue an error if there is not enough `dstCapacity` to hold the compressed content.
*   Frame is supposed already started (header already produced)
*  @return : compressed size, or an error code
*/
static size_t ZSTD_compress_frameChunk(ZSTD_CCtx* cctx,
                                     void* dst, size_t dstCapacity,
                               const void* src, size_t srcSize,
                                     U32 lastFrameChunk)
{
    ZSTD_rust_frameChunkState state;
    state.callbackContext = cctx;
    state.tmpWorkspace = cctx->tmpWorkspace;
    state.checksumState = &cctx->xxhState;
    state.isFirstBlock = &cctx->isFirstBlock;
    state.stage = &cctx->stage;
    state.tmpWkspSize = cctx->tmpWkspSize;
    state.blockSizeMax = cctx->blockSizeMax;
    state.savings = (S64)cctx->consumedSrcSize - (S64)cctx->producedCSize;
    state.preBlockSplitterLevel = cctx->appliedParams.preBlockSplitter_level;
    state.strategy = (int)cctx->appliedParams.cParams.strategy;
    state.useTargetCBlockSize = ZSTD_useTargetCBlockSize(&cctx->appliedParams);
    state.blockSplitterEnabled = ZSTD_blockSplitterEnabled(&cctx->appliedParams);
    state.checksumFlag = cctx->appliedParams.fParams.checksumFlag;
    state.endingStage = (int)ZSTDcs_ending;
    state.prepareBlock = ZSTD_rust_frameChunk_prepareBlock;
    state.compressTarget = ZSTD_rust_frameChunk_compressTarget;
    state.compressSplit = ZSTD_rust_frameChunk_compressSplit;
    state.compressInternal = ZSTD_rust_frameChunk_compressInternal;
    state.updateChecksum = ZSTD_rust_frameChunk_updateChecksum;
    return ZSTD_rust_compressFrameChunk(
            &state, dst, dstCapacity, src, srcSize, lastFrameChunk);
}


static size_t ZSTD_writeFrameHeader(void* dst, size_t dstCapacity,
                                    const ZSTD_CCtx_params* params,
                                    U64 pledgedSrcSize, U32 dictID)
{
    return ZSTD_rust_writeFrameHeader(dst, dstCapacity,
                                      params->fParams.noDictIDFlag,
                                      params->fParams.checksumFlag,
                                      params->fParams.contentSizeFlag,
                                      (int)params->format,
                                      params->cParams.windowLog,
                                      pledgedSrcSize, dictID);
}

void ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSeq)
{
    assert(cctx->stage == ZSTDcs_init);
    assert(nbSeq == 0 || cctx->appliedParams.ldmParams.enableLdm != ZSTD_ps_enable);
    cctx->externSeqStore.seq = seq;
    cctx->externSeqStore.size = nbSeq;
    cctx->externSeqStore.capacity = nbSeq;
    cctx->externSeqStore.pos = 0;
    cctx->externSeqStore.posInSequence = 0;
}


static size_t ZSTD_compressContinue_internal (ZSTD_CCtx* cctx,
                              void* dst, size_t dstCapacity,
                        const void* src, size_t srcSize,
                               U32 frame, U32 lastFrameChunk)
{
    ZSTD_MatchState_t* const ms = &cctx->blockState.matchState;
    size_t fhSize = 0;

    DEBUGLOG(5, "ZSTD_compressContinue_internal, stage: %u, srcSize: %u",
                cctx->stage, (unsigned)srcSize);
    RETURN_ERROR_IF(cctx->stage==ZSTDcs_created, stage_wrong,
                    "missing init (ZSTD_compressBegin)");

    if (frame && (cctx->stage==ZSTDcs_init)) {
        fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, &cctx->appliedParams,
                                       cctx->pledgedSrcSizePlusOne-1, cctx->dictID);
        FORWARD_IF_ERROR(fhSize, "ZSTD_writeFrameHeader failed");
        assert(fhSize <= dstCapacity);
        dstCapacity -= fhSize;
        dst = (char*)dst + fhSize;
        cctx->stage = ZSTDcs_ongoing;
    }

    if (!srcSize) return fhSize;  /* do not generate an empty block if no input */

    if (!ZSTD_window_update(&ms->window, src, srcSize, ms->forceNonContiguous)) {
        ms->forceNonContiguous = 0;
        ms->nextToUpdate = ms->window.dictLimit;
    }
    if (cctx->appliedParams.ldmParams.enableLdm == ZSTD_ps_enable) {
        ZSTD_window_update(&cctx->ldmState.window, src, srcSize, /* forceNonContiguous */ 0);
    }

    if (!frame) {
        /* overflow check and correction for block mode */
        ZSTD_overflowCorrectIfNeeded(
            ms, &cctx->workspace, &cctx->appliedParams,
            src, (BYTE const*)src + srcSize);
    }

    DEBUGLOG(5, "ZSTD_compressContinue_internal (blockSize=%u)", (unsigned)cctx->blockSizeMax);
    {   size_t const cSize = frame ?
                             ZSTD_compress_frameChunk (cctx, dst, dstCapacity, src, srcSize, lastFrameChunk) :
                             ZSTD_compressBlock_internal (cctx, dst, dstCapacity, src, srcSize, 0 /* frame */);
        int srcSizeWrong;
        FORWARD_IF_ERROR(cSize, "%s", frame ? "ZSTD_compress_frameChunk failed" : "ZSTD_compressBlock_internal failed");
        srcSizeWrong = ZSTD_rust_updateFrameProgression(
                &cctx->consumedSrcSize, &cctx->producedCSize,
                cctx->pledgedSrcSizePlusOne, srcSize, cSize, fhSize);
        assert(!(cctx->appliedParams.fParams.contentSizeFlag && cctx->pledgedSrcSizePlusOne == 0));
        if (cctx->pledgedSrcSizePlusOne != 0) {  /* control src size */
            ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN == (unsigned long long)-1);
            RETURN_ERROR_IF(
                srcSizeWrong,
                srcSize_wrong,
                "error : pledgedSrcSize = %u, while realSrcSize >= %u",
                (unsigned)cctx->pledgedSrcSizePlusOne-1,
                (unsigned)cctx->consumedSrcSize);
        }
        return cSize + fhSize;
    }
}

size_t ZSTD_compressContinue_public(ZSTD_CCtx* cctx,
                                        void* dst, size_t dstCapacity,
                                  const void* src, size_t srcSize)
{
    DEBUGLOG(5, "ZSTD_compressContinue (srcSize=%u)", (unsigned)srcSize);
    return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1 /* frame mode */, 0 /* last chunk */);
}

/* NOTE: Must just wrap ZSTD_compressContinue_public() */
size_t ZSTD_compressContinue(ZSTD_CCtx* cctx,
                             void* dst, size_t dstCapacity,
                       const void* src, size_t srcSize)
{
    return ZSTD_compressContinue_public(cctx, dst, dstCapacity, src, srcSize);
}

static size_t ZSTD_getBlockSize_deprecated(const ZSTD_CCtx* cctx)
{
    ZSTD_compressionParameters const cParams = cctx->appliedParams.cParams;
    assert(!ZSTD_checkCParams(cParams));
    return ZSTD_rust_params_getBlockSize(cctx->appliedParams.maxBlockSize, cParams.windowLog);
}

/* NOTE: Must just wrap ZSTD_getBlockSize_deprecated() */
size_t ZSTD_getBlockSize(const ZSTD_CCtx* cctx)
{
    return ZSTD_getBlockSize_deprecated(cctx);
}

/* NOTE: Must just wrap ZSTD_compressBlock_deprecated() */
size_t ZSTD_compressBlock_deprecated(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
    DEBUGLOG(5, "ZSTD_compressBlock: srcSize = %u", (unsigned)srcSize);
    { size_t const blockSizeMax = ZSTD_getBlockSize_deprecated(cctx);
      RETURN_ERROR_IF(srcSize > blockSizeMax, srcSize_wrong, "input is larger than a block"); }

    return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 0 /* frame mode */, 0 /* last chunk */);
}

/* NOTE: Must just wrap ZSTD_compressBlock_deprecated() */
size_t ZSTD_compressBlock(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
    return ZSTD_compressBlock_deprecated(cctx, dst, dstCapacity, src, srcSize);
}

/*! ZSTD_loadDictionaryContent() :
 *  @return : 0, or an error code
 */
static size_t
ZSTD_loadDictionaryContent(ZSTD_MatchState_t* ms,
                        ldmState_t* ls,
                        ZSTD_cwksp* ws,
                        ZSTD_CCtx_params const* params,
                        const void* src, size_t srcSize,
                        ZSTD_dictTableLoadMethod_e dtlm,
                        ZSTD_tableFillPurpose_e tfp)
{
    const BYTE* ip = (const BYTE*) src;
    const BYTE* const iend = ip + srcSize;
    int const loadLdmDict = params->ldmParams.enableLdm == ZSTD_ps_enable && ls != NULL;

    /* Assert that the ms params match the params we're being given */
    ZSTD_assertEqualCParams(params->cParams, ms->cParams);

    {   /* Ensure large dictionaries can't cause index overflow */

        /* Allow the dictionary to set indices up to exactly ZSTD_CURRENT_MAX.
         * Dictionaries right at the edge will immediately trigger overflow
         * correction, but I don't want to insert extra constraints here.
         */
        U32 maxDictSize = ZSTD_CURRENT_MAX - ZSTD_WINDOW_START_INDEX;

        int const CDictTaggedIndices = ZSTD_CDictIndicesAreTagged(&params->cParams);
        if (CDictTaggedIndices && tfp == ZSTD_tfp_forCDict) {
            /* Some dictionary matchfinders in zstd use "short cache",
             * which treats the lower ZSTD_SHORT_CACHE_TAG_BITS of each
             * CDict hashtable entry as a tag rather than as part of an index.
             * When short cache is used, we need to truncate the dictionary
             * so that its indices don't overlap with the tag. */
            U32 const shortCacheMaxDictSize = (1u << (32 - ZSTD_SHORT_CACHE_TAG_BITS)) - ZSTD_WINDOW_START_INDEX;
            maxDictSize = MIN(maxDictSize, shortCacheMaxDictSize);
            assert(!loadLdmDict);
        }

        /* If the dictionary is too large, only load the suffix of the dictionary. */
        if (srcSize > maxDictSize) {
            ip = iend - maxDictSize;
            src = ip;
            srcSize = maxDictSize;
        }
    }

    if (srcSize > ZSTD_CHUNKSIZE_MAX) {
        /* We must have cleared our windows when our source is this large. */
        assert(ZSTD_window_isEmpty(ms->window));
        if (loadLdmDict) assert(ZSTD_window_isEmpty(ls->window));
    }
    ZSTD_window_update(&ms->window, src, srcSize, /* forceNonContiguous */ 0);

    DEBUGLOG(4, "ZSTD_loadDictionaryContent: useRowMatchFinder=%d", (int)params->useRowMatchFinder);

    if (loadLdmDict) { /* Load the entire dict into LDM matchfinders. */
        DEBUGLOG(4, "ZSTD_loadDictionaryContent: Trigger loadLdmDict");
        ZSTD_window_update(&ls->window, src, srcSize, /* forceNonContiguous */ 0);
        ls->loadedDictEnd = params->forceWindow ? 0 : (U32)(iend - ls->window.base);
        ZSTD_ldm_fillHashTable(ls, ip, iend, &params->ldmParams);
        DEBUGLOG(4, "ZSTD_loadDictionaryContent: ZSTD_ldm_fillHashTable completes");
    }

    /* If the dict is larger than we can reasonably index in our tables, only load the suffix. */
    {   U32 maxDictSize = 1U << MIN(MAX(params->cParams.hashLog + 3, params->cParams.chainLog + 1), 31);
        if (srcSize > maxDictSize) {
            ip = iend - maxDictSize;
            src = ip;
            srcSize = maxDictSize;
        }
    }

    ms->nextToUpdate = (U32)(ip - ms->window.base);
    ms->loadedDictEnd = params->forceWindow ? 0 : (U32)(iend - ms->window.base);
    ms->forceNonContiguous = params->deterministicRefPrefix;

    if (srcSize <= HASH_READ_SIZE) return 0;

    ZSTD_overflowCorrectIfNeeded(ms, ws, params, ip, iend);

    switch(params->cParams.strategy)
    {
    case ZSTD_fast:
        ZSTD_fillHashTable(ms, iend, dtlm, tfp);
        break;
    case ZSTD_dfast:
#ifndef ZSTD_EXCLUDE_DFAST_BLOCK_COMPRESSOR
        ZSTD_fillDoubleHashTable(ms, iend, dtlm, tfp);
#else
        assert(0); /* shouldn't be called: cparams should've been adjusted. */
#endif
        break;

    case ZSTD_greedy:
    case ZSTD_lazy:
    case ZSTD_lazy2:
#if !defined(ZSTD_EXCLUDE_GREEDY_BLOCK_COMPRESSOR) \
 || !defined(ZSTD_EXCLUDE_LAZY_BLOCK_COMPRESSOR) \
 || !defined(ZSTD_EXCLUDE_LAZY2_BLOCK_COMPRESSOR)
        assert(srcSize >= HASH_READ_SIZE);
        if (ms->dedicatedDictSearch) {
            assert(ms->chainTable != NULL);
            ZSTD_dedicatedDictSearch_lazy_loadDictionary(ms, iend-HASH_READ_SIZE);
        } else {
            assert(params->useRowMatchFinder != ZSTD_ps_auto);
            if (params->useRowMatchFinder == ZSTD_ps_enable) {
                size_t const tagTableSize = ((size_t)1 << params->cParams.hashLog);
                ZSTD_memset(ms->tagTable, 0, tagTableSize);
                ZSTD_row_update(ms, iend-HASH_READ_SIZE);
                DEBUGLOG(4, "Using row-based hash table for lazy dict");
            } else {
                ZSTD_insertAndFindFirstIndex(ms, iend-HASH_READ_SIZE);
                DEBUGLOG(4, "Using chain-based hash table for lazy dict");
            }
        }
#else
        assert(0); /* shouldn't be called: cparams should've been adjusted. */
#endif
        break;

    case ZSTD_btlazy2:   /* we want the dictionary table fully sorted */
    case ZSTD_btopt:
    case ZSTD_btultra:
    case ZSTD_btultra2:
#if !defined(ZSTD_EXCLUDE_BTLAZY2_BLOCK_COMPRESSOR) \
 || !defined(ZSTD_EXCLUDE_BTOPT_BLOCK_COMPRESSOR) \
 || !defined(ZSTD_EXCLUDE_BTULTRA_BLOCK_COMPRESSOR)
        assert(srcSize >= HASH_READ_SIZE);
        DEBUGLOG(4, "Fill %u bytes into the Binary Tree", (unsigned)srcSize);
        ZSTD_updateTree(ms, iend-HASH_READ_SIZE, iend);
#else
        assert(0); /* shouldn't be called: cparams should've been adjusted. */
#endif
        break;

    default:
        assert(0);  /* not possible : not a valid strategy id */
    }

    ms->nextToUpdate = (U32)(iend - ms->window.base);
    return 0;
}


/* Dictionary entropy-header loading lives in Rust; C keeps the public internal
 * symbol and the dictionary-content orchestration around it. */
size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
                         const void* const dict, size_t dictSize)
{
    return ZSTD_rust_loadCEntropy(bs, workspace, dict, dictSize);
}

/* Dictionary format :
 * See :
 * https://github.com/facebook/zstd/blob/release/doc/zstd_compression_format.md#dictionary-format
 */
/*! ZSTD_loadZstdDictionary() :
 * @return : dictID, or an error code
 *  assumptions : magic number supposed already checked
 *                dictSize supposed >= 8
 */
static size_t ZSTD_loadZstdDictionary(ZSTD_compressedBlockState_t* bs,
                                      ZSTD_MatchState_t* ms,
                                      ZSTD_cwksp* ws,
                                      ZSTD_CCtx_params const* params,
                                      const void* dict, size_t dictSize,
                                      ZSTD_dictTableLoadMethod_e dtlm,
                                      ZSTD_tableFillPurpose_e tfp,
                                      void* workspace)
{
    const BYTE* dictPtr = (const BYTE*)dict;
    const BYTE* const dictEnd = dictPtr + dictSize;
    size_t dictID;
    size_t eSize;
    ZSTD_STATIC_ASSERT(HUF_WORKSPACE_SIZE >= (1<<MAX(MLFSELog,LLFSELog)));
    assert(dictSize >= 8);
    assert(MEM_readLE32(dictPtr) == ZSTD_MAGIC_DICTIONARY);

    dictID = params->fParams.noDictIDFlag ? 0 :  MEM_readLE32(dictPtr + 4 /* skip magic number */ );
    eSize = ZSTD_loadCEntropy(bs, workspace, dict, dictSize);
    FORWARD_IF_ERROR(eSize, "ZSTD_loadCEntropy failed");
    dictPtr += eSize;

    {
        size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
        FORWARD_IF_ERROR(ZSTD_loadDictionaryContent(
            ms, NULL, ws, params, dictPtr, dictContentSize, dtlm, tfp), "");
    }
    return dictID;
}

/** ZSTD_compress_insertDictionary() :
*   @return : dictID, or an error code */
static size_t
ZSTD_compress_insertDictionary(ZSTD_compressedBlockState_t* bs,
                               ZSTD_MatchState_t* ms,
                               ldmState_t* ls,
                               ZSTD_cwksp* ws,
                         const ZSTD_CCtx_params* params,
                         const void* dict, size_t dictSize,
                               ZSTD_dictContentType_e dictContentType,
                               ZSTD_dictTableLoadMethod_e dtlm,
                               ZSTD_tableFillPurpose_e tfp,
                               void* workspace)
{
    DEBUGLOG(4, "ZSTD_compress_insertDictionary (dictSize=%u)", (U32)dictSize);
    if ((dict==NULL) || (dictSize<8)) {
        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong, "");
        return 0;
    }

    ZSTD_reset_compressedBlockState(bs);

    /* dict restricted modes */
    if (dictContentType == ZSTD_dct_rawContent)
        return ZSTD_loadDictionaryContent(ms, ls, ws, params, dict, dictSize, dtlm, tfp);

    if (MEM_readLE32(dict) != ZSTD_MAGIC_DICTIONARY) {
        if (dictContentType == ZSTD_dct_auto) {
            DEBUGLOG(4, "raw content dictionary detected");
            return ZSTD_loadDictionaryContent(
                ms, ls, ws, params, dict, dictSize, dtlm, tfp);
        }
        RETURN_ERROR_IF(dictContentType == ZSTD_dct_fullDict, dictionary_wrong, "");
        assert(0);   /* impossible */
    }

    /* dict as full zstd dictionary */
    return ZSTD_loadZstdDictionary(
        bs, ms, ws, params, dict, dictSize, dtlm, tfp, workspace);
}

#define ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF (128 KB)
#define ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER (6ULL)

/*! ZSTD_compressBegin_internal() :
 * Assumption : either @dict OR @cdict (or none) is non-NULL, never both
 * @return : 0, or an error code */
static size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
                                    const void* dict, size_t dictSize,
                                    ZSTD_dictContentType_e dictContentType,
                                    ZSTD_dictTableLoadMethod_e dtlm,
                                    const ZSTD_CDict* cdict,
                                    const ZSTD_CCtx_params* params, U64 pledgedSrcSize,
                                    ZSTD_buffered_policy_e zbuff)
{
    size_t const dictContentSize = cdict ? cdict->dictContentSize : dictSize;
#if ZSTD_TRACE
    cctx->traceCtx = (ZSTD_trace_compress_begin != NULL) ? ZSTD_trace_compress_begin(cctx) : 0;
#endif
    DEBUGLOG(4, "ZSTD_compressBegin_internal: wlog=%u", params->cParams.windowLog);
    /* params are supposed to be fully validated at this point */
    assert(!ZSTD_isError(ZSTD_checkCParams(params->cParams)));
    assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
    if ( (cdict)
      && (cdict->dictContentSize > 0)
      && ( pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF
        || pledgedSrcSize < cdict->dictContentSize * ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER
        || pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN
        || cdict->compressionLevel == 0)
      && (params->attachDictPref != ZSTD_dictForceLoad) ) {
        return ZSTD_resetCCtx_usingCDict(cctx, cdict, params, pledgedSrcSize, zbuff);
    }

    FORWARD_IF_ERROR( ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
                                     dictContentSize,
                                     ZSTDcrp_makeClean, zbuff) , "");
    {   size_t const dictID = cdict ?
                ZSTD_compress_insertDictionary(
                        cctx->blockState.prevCBlock, &cctx->blockState.matchState,
                        &cctx->ldmState, &cctx->workspace, &cctx->appliedParams, cdict->dictContent,
                        cdict->dictContentSize, cdict->dictContentType, dtlm,
                        ZSTD_tfp_forCCtx, cctx->tmpWorkspace)
              : ZSTD_compress_insertDictionary(
                        cctx->blockState.prevCBlock, &cctx->blockState.matchState,
                        &cctx->ldmState, &cctx->workspace, &cctx->appliedParams, dict, dictSize,
                        dictContentType, dtlm, ZSTD_tfp_forCCtx, cctx->tmpWorkspace);
        FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
        assert(dictID <= UINT_MAX);
        cctx->dictID = (U32)dictID;
        cctx->dictContentSize = dictContentSize;
    }
    return 0;
}

size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
                                    const void* dict, size_t dictSize,
                                    ZSTD_dictContentType_e dictContentType,
                                    ZSTD_dictTableLoadMethod_e dtlm,
                                    const ZSTD_CDict* cdict,
                                    const ZSTD_CCtx_params* params,
                                    unsigned long long pledgedSrcSize)
{
    DEBUGLOG(4, "ZSTD_compressBegin_advanced_internal: wlog=%u", params->cParams.windowLog);
    /* compression parameters verification and optimization */
    FORWARD_IF_ERROR( ZSTD_checkCParams(params->cParams) , "");
    return ZSTD_compressBegin_internal(cctx,
                                       dict, dictSize, dictContentType, dtlm,
                                       cdict,
                                       params, pledgedSrcSize,
                                       ZSTDb_not_buffered);
}

/*! ZSTD_compressBegin_advanced() :
*   @return : 0, or an error code */
size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx,
                             const void* dict, size_t dictSize,
                                   ZSTD_parameters params, unsigned long long pledgedSrcSize)
{
    ZSTD_CCtx_params cctxParams;
    ZSTD_CCtxParams_init_internal(&cctxParams, &params, ZSTD_NO_CLEVEL);
    return ZSTD_compressBegin_advanced_internal(cctx,
                                            dict, dictSize, ZSTD_dct_auto, ZSTD_dtlm_fast,
                                            NULL /*cdict*/,
                                            &cctxParams, pledgedSrcSize);
}

static size_t
ZSTD_compressBegin_usingDict_deprecated(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel)
{
    ZSTD_CCtx_params cctxParams;
    {   ZSTD_parameters const params = ZSTD_getParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_noAttachDict);
        ZSTD_CCtxParams_init_internal(&cctxParams, &params, (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT : compressionLevel);
    }
    DEBUGLOG(4, "ZSTD_compressBegin_usingDict (dictSize=%u)", (unsigned)dictSize);
    return ZSTD_compressBegin_internal(cctx, dict, dictSize, ZSTD_dct_auto, ZSTD_dtlm_fast, NULL,
                                       &cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, ZSTDb_not_buffered);
}

size_t
ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel)
{
    return ZSTD_compressBegin_usingDict_deprecated(cctx, dict, dictSize, compressionLevel);
}

size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel)
{
    return ZSTD_compressBegin_usingDict_deprecated(cctx, NULL, 0, compressionLevel);
}


/*! ZSTD_writeEpilogue() :
*   Ends a frame.
*   @return : nb of bytes written into dst (or an error code) */
static size_t ZSTD_writeEpilogue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity)
{
    U32 const checksum = cctx->appliedParams.fParams.checksumFlag
        ? (U32)XXH64_digest(&cctx->xxhState)
        : 0;
    DEBUGLOG(4, "ZSTD_writeEpilogue");
    if (cctx->appliedParams.fParams.checksumFlag)
        DEBUGLOG(4, "ZSTD_writeEpilogue: write checksum : %08X", (unsigned)checksum);
    return ZSTD_rust_writeEpilogue(
            dst, dstCapacity, (int*)&cctx->stage,
            cctx->appliedParams.fParams.noDictIDFlag,
            cctx->appliedParams.fParams.checksumFlag,
            cctx->appliedParams.fParams.contentSizeFlag,
            (int)cctx->appliedParams.format,
            cctx->appliedParams.cParams.windowLog,
            checksum);
}

void ZSTD_CCtx_trace(ZSTD_CCtx* cctx, size_t extraCSize)
{
#if ZSTD_TRACE
    if (cctx->traceCtx && ZSTD_trace_compress_end != NULL) {
        int const streaming = cctx->inBuffSize > 0 || cctx->outBuffSize > 0 || cctx->appliedParams.nbWorkers > 0;
        ZSTD_Trace trace;
        ZSTD_memset(&trace, 0, sizeof(trace));
        trace.version = ZSTD_VERSION_NUMBER;
        trace.streaming = streaming;
        trace.dictionaryID = cctx->dictID;
        trace.dictionarySize = cctx->dictContentSize;
        trace.uncompressedSize = cctx->consumedSrcSize;
        trace.compressedSize = cctx->producedCSize + extraCSize;
        trace.params = &cctx->appliedParams;
        trace.cctx = cctx;
        ZSTD_trace_compress_end(cctx->traceCtx, &trace);
    }
    cctx->traceCtx = 0;
#else
    (void)cctx;
    (void)extraCSize;
#endif
}

size_t ZSTD_compressEnd_public(ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize)
{
    size_t endResult;
    size_t const cSize = ZSTD_compressContinue_internal(cctx,
                                dst, dstCapacity, src, srcSize,
                                1 /* frame mode */, 1 /* last chunk */);
    FORWARD_IF_ERROR(cSize, "ZSTD_compressContinue_internal failed");
    endResult = ZSTD_writeEpilogue(cctx, (char*)dst + cSize, dstCapacity-cSize);
    FORWARD_IF_ERROR(endResult, "ZSTD_writeEpilogue failed");
    assert(!(cctx->appliedParams.fParams.contentSizeFlag && cctx->pledgedSrcSizePlusOne == 0));
    if (cctx->pledgedSrcSizePlusOne != 0) {  /* control src size */
        ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN == (unsigned long long)-1);
        DEBUGLOG(4, "end of frame : controlling src size");
        RETURN_ERROR_IF(
            cctx->pledgedSrcSizePlusOne != cctx->consumedSrcSize+1,
            srcSize_wrong,
             "error : pledgedSrcSize = %u, while realSrcSize = %u",
            (unsigned)cctx->pledgedSrcSizePlusOne-1,
            (unsigned)cctx->consumedSrcSize);
    }
    ZSTD_CCtx_trace(cctx, endResult);
    return cSize + endResult;
}

/* NOTE: Must just wrap ZSTD_compressEnd_public() */
size_t ZSTD_compressEnd(ZSTD_CCtx* cctx,
                        void* dst, size_t dstCapacity,
                  const void* src, size_t srcSize)
{
    return ZSTD_compressEnd_public(cctx, dst, dstCapacity, src, srcSize);
}

size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize,
                         const void* dict,size_t dictSize,
                               ZSTD_parameters params)
{
    DEBUGLOG(4, "ZSTD_compress_advanced");
    FORWARD_IF_ERROR(ZSTD_checkCParams(params.cParams), "");
    ZSTD_CCtxParams_init_internal(&cctx->simpleApiParams, &params, ZSTD_NO_CLEVEL);
    return ZSTD_compress_advanced_internal(cctx,
                                           dst, dstCapacity,
                                           src, srcSize,
                                           dict, dictSize,
                                           &cctx->simpleApiParams);
}

/* Internal */
size_t ZSTD_compress_advanced_internal(
        ZSTD_CCtx* cctx,
        void* dst, size_t dstCapacity,
        const void* src, size_t srcSize,
        const void* dict,size_t dictSize,
        const ZSTD_CCtx_params* params)
{
    DEBUGLOG(4, "ZSTD_compress_advanced_internal (srcSize:%u)", (unsigned)srcSize);
    FORWARD_IF_ERROR( ZSTD_compressBegin_internal(cctx,
                         dict, dictSize, ZSTD_dct_auto, ZSTD_dtlm_fast, NULL,
                         params, srcSize, ZSTDb_not_buffered) , "");
    return ZSTD_compressEnd_public(cctx, dst, dstCapacity, src, srcSize);
}

size_t ZSTD_compress_usingDict(ZSTD_CCtx* cctx,
                               void* dst, size_t dstCapacity,
                         const void* src, size_t srcSize,
                         const void* dict, size_t dictSize,
                               int compressionLevel)
{
    {
        ZSTD_parameters const params = ZSTD_getParams_internal(compressionLevel, srcSize, dict ? dictSize : 0, ZSTD_cpm_noAttachDict);
        assert(params.fParams.contentSizeFlag == 1);
        ZSTD_CCtxParams_init_internal(&cctx->simpleApiParams, &params, (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT: compressionLevel);
    }
    DEBUGLOG(4, "ZSTD_compress_usingDict (srcSize=%u)", (unsigned)srcSize);
    return ZSTD_compress_advanced_internal(cctx, dst, dstCapacity, src, srcSize, dict, dictSize, &cctx->simpleApiParams);
}

/* ZSTD_compressCCtx() is implemented by rust/src/zstd_compress.rs. */

/* The Rust simple API still needs the C-owned context reset, but does not
 * cross the private context layout. */
size_t ZSTD_rust_resetCCtxForSimpleCompression(void* cctx)
{
    return ZSTD_CCtx_reset((ZSTD_CCtx*)cctx, ZSTD_reset_session_and_parameters);
}

size_t ZSTD_rust_prepareCCtxForSimpleCompression(void* opaqueCctx,
                                                 size_t srcSize,
                                                 int compressionLevel)
{
    ZSTD_CCtx* const cctx = (ZSTD_CCtx*)opaqueCctx;
    ZSTD_CCtx_params params;
    ZSTD_parameters const zstdParams = ZSTD_getParams_internal(
            compressionLevel, srcSize, 0, ZSTD_cpm_noAttachDict);
    ZSTD_CCtxParams_init_internal(
            &params, &zstdParams,
            compressionLevel == 0 ? ZSTD_CLEVEL_DEFAULT : compressionLevel);
    FORWARD_IF_ERROR(ZSTD_compressBegin_internal(
            cctx, NULL, 0, ZSTD_dct_auto, ZSTD_dtlm_fast, NULL,
            &params, srcSize, ZSTDb_not_buffered), "");
    return ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
}

size_t ZSTD_rust_resetCCtxForSimpleCompressionSession(void* cctx)
{
    return ZSTD_CCtx_reset((ZSTD_CCtx*)cctx, ZSTD_reset_session_only);
}

void ZSTD_rust_markSimpleCompression2Complete(void* cctx)
{
    ((ZSTD_CCtx*)cctx)->rustSimpleCompress2Completed = 1;
}

/* Return the requested level when the context has only the parameters that
 * the Rust frame path currently implements.  All other contexts continue
 * through ZSTD_compress2_c(), preserving the full C stateful implementation
 * while this boundary is migrated incrementally. */
int ZSTD_rust_simpleCompress2Level(const void* opaqueCctx, size_t srcSize)
{
    ZSTD_CCtx const* const cctx = (ZSTD_CCtx const*)opaqueCctx;
    ZSTD_CCtx_params const* const params = cctx ? &cctx->requestedParams : NULL;
    ZSTD_compressionParameters const cParams = params
        ? ZSTD_getCParams_internal(params->compressionLevel,
                                   srcSize, 0,
                                   ZSTD_cpm_noAttachDict)
        : (ZSTD_compressionParameters){ 0 };
    if (params == NULL
        || params->format != ZSTD_f_zstd1
        || params->fParams.contentSizeFlag == 0
        || params->fParams.checksumFlag != 0
        || params->cParams.windowLog != 0
        || params->cParams.chainLog != 0
        || params->cParams.hashLog != 0
        || params->cParams.searchLog != 0
        || params->cParams.minMatch != 0
        || params->cParams.targetLength != 0
        || params->cParams.strategy != 0
        || params->forceWindow != 0
        || params->targetCBlockSize != 0
        || params->srcSizeHint != 0
        || params->attachDictPref != ZSTD_dictDefaultAttach
        || params->literalCompressionMode != (ZSTD_ParamSwitch_e)ZSTD_lcm_auto
        || params->nbWorkers != 0
        || params->jobSize != 0
        || params->overlapLog != 0
        || params->rsyncable != 0
        || params->ldmParams.enableLdm != ZSTD_ps_auto
        || params->ldmParams.hashLog != 0
        || (params->ldmParams.bucketSizeLog != 0
            && params->ldmParams.bucketSizeLog != 9999)
        || params->ldmParams.minMatchLength != 0
        || (params->ldmParams.hashRateLog != 0
            && params->ldmParams.hashRateLog != 9999)
        || params->ldmParams.windowLog != 0
        || params->enableDedicatedDictSearch != 0
        || params->inBufferMode != ZSTD_bm_buffered
        || params->outBufferMode != ZSTD_bm_buffered
        || params->blockDelimiters != ZSTD_sf_noBlockDelimiters
        || params->validateSequences != 0
        || params->postBlockSplitter != ZSTD_ps_auto
        || params->preBlockSplitter_level != 0
        || params->maxBlockSize != 0
        || cctx->rustSimpleCompress2MaxBlockSizeSet != 0
        || params->useRowMatchFinder != ZSTD_ps_auto
        || params->deterministicRefPrefix != 0
        || params->prefetchCDictTables != ZSTD_ps_auto
        || params->enableMatchFinderFallback != 0
        || params->extSeqProdFunc != NULL
        || params->searchForExternalRepcodes != ZSTD_ps_auto
        || cctx->pool != NULL
        || cctx->seqCollector.collectSequences != 0
        || cctx->cdict != NULL
        || cctx->prefixDict.dict != NULL
        || cctx->localDict.dict != NULL
        || cctx->localDict.dictBuffer != NULL
        || cctx->localDict.cdict != NULL) {
        return (-2147483647 - 1);
    }
    /* The Rust frame leaf currently implements only the fast and double-fast
     * match finders.  Keep lazy and optimal strategies on the stateful path,
     * which owns their strategy-specific match-table lifecycle. */
    if (cParams.strategy != ZSTD_fast && cParams.strategy != ZSTD_dfast) {
        return (-2147483647 - 1);
    }
    return params->compressionLevel;
}

/* Return the simple level only while a new stream frame can be initialized.
 * Rust handles this complete-input case; all other stream states stay on the
 * original implementation so partial output and advanced buffering remain
 * governed by the C state machine. */
int ZSTD_rust_simpleCompressStream2Level(const void* opaqueCctx, size_t srcSize)
{
    ZSTD_CCtx const* const cctx = (ZSTD_CCtx const*)opaqueCctx;
    if (cctx == NULL
        || cctx->streamStage != zcss_init
        || cctx->pledgedSrcSizePlusOne != 0
        || cctx->rustSimpleCompress2Completed != 0) {
        return (-2147483647 - 1);
    }
    return ZSTD_rust_simpleCompress2Level(opaqueCctx, srcSize);
}

/* ZSTD_compress() is implemented by rust/src/zstd_compress.rs. */


/* =====  Dictionary API  ===== */

/*! ZSTD_estimateCDictSize_advanced() :
 *  Estimate amount of memory that will be needed to create a dictionary with following arguments */
size_t ZSTD_estimateCDictSize_advanced(
        size_t dictSize, ZSTD_compressionParameters cParams,
        ZSTD_dictLoadMethod_e dictLoadMethod)
{
    ZSTD_rustCDictSizing sizing;
    sizing.cdictSize = sizeof(ZSTD_CDict);
    sizing.hufWorkspaceSize = HUF_WORKSPACE_SIZE;
    sizing.hashLog3Max = ZSTD_HASHLOG3_MAX;
    sizing.matchTSize = sizeof(ZSTD_match_t);
    sizing.optimalTSize = sizeof(ZSTD_optimal_t);
    sizing.asanRedzoneSize = ZSTD_RUST_ASAN_REDZONE_SIZE;
    return ZSTD_rust_params_estimateCDictSizeFromCParams(
            dictSize, cParams, (int)dictLoadMethod, &sizing);
}

size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel)
{
    ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
    return ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byCopy);
}

size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict)
{
    size_t objectSize, workspaceSize;
    if (cdict==NULL) return 0;   /* support sizeof on NULL */
    DEBUGLOG(5, "sizeof(*cdict) : %u", (unsigned)sizeof(*cdict));
    /* cdict may be in the workspace */
    objectSize = cdict->workspace.workspace == cdict ? 0 : sizeof(*cdict);
    workspaceSize = ZSTD_cwksp_sizeof(&cdict->workspace);
    return ZSTD_rust_sizeofCDict(objectSize, workspaceSize);
}

static size_t ZSTD_initCDict_internal(
                    ZSTD_CDict* cdict,
              const void* dictBuffer, size_t dictSize,
                    ZSTD_dictLoadMethod_e dictLoadMethod,
                    ZSTD_dictContentType_e dictContentType,
                    ZSTD_CCtx_params params)
{
    DEBUGLOG(3, "ZSTD_initCDict_internal (dictContentType:%u)", (unsigned)dictContentType);
    assert(!ZSTD_checkCParams(params.cParams));
    cdict->matchState.cParams = params.cParams;
    cdict->matchState.dedicatedDictSearch = params.enableDedicatedDictSearch;
    if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dictBuffer) || (!dictSize)) {
        cdict->dictContent = dictBuffer;
    } else {
         void *internalBuffer = ZSTD_cwksp_reserve_object(&cdict->workspace, ZSTD_cwksp_align(dictSize, sizeof(void*)));
        RETURN_ERROR_IF(!internalBuffer, memory_allocation, "NULL pointer!");
        cdict->dictContent = internalBuffer;
        ZSTD_memcpy(internalBuffer, dictBuffer, dictSize);
    }
    cdict->dictContentSize = dictSize;
    cdict->dictContentType = dictContentType;

    cdict->entropyWorkspace = (U32*)ZSTD_cwksp_reserve_object(&cdict->workspace, HUF_WORKSPACE_SIZE);


    /* Reset the state to no dictionary */
    ZSTD_reset_compressedBlockState(&cdict->cBlockState);
    FORWARD_IF_ERROR(ZSTD_reset_matchState(
        &cdict->matchState,
        &cdict->workspace,
        &params.cParams,
        params.useRowMatchFinder,
        ZSTDcrp_makeClean,
        ZSTDirp_reset,
        ZSTD_resetTarget_CDict), "");
    /* (Maybe) load the dictionary
     * Skips loading the dictionary if it is < 8 bytes.
     */
    {   params.compressionLevel = ZSTD_CLEVEL_DEFAULT;
        params.fParams.contentSizeFlag = 1;
        {   size_t const dictID = ZSTD_compress_insertDictionary(
                    &cdict->cBlockState, &cdict->matchState, NULL, &cdict->workspace,
                    &params, cdict->dictContent, cdict->dictContentSize,
                    dictContentType, ZSTD_dtlm_full, ZSTD_tfp_forCDict, cdict->entropyWorkspace);
            FORWARD_IF_ERROR(dictID, "ZSTD_compress_insertDictionary failed");
            assert(dictID <= (size_t)(U32)-1);
            cdict->dictID = (U32)dictID;
        }
    }

    return 0;
}

static ZSTD_CDict*
ZSTD_createCDict_advanced_internal(size_t dictSize,
                                ZSTD_dictLoadMethod_e dictLoadMethod,
                                ZSTD_compressionParameters cParams,
                                ZSTD_ParamSwitch_e useRowMatchFinder,
                                int enableDedicatedDictSearch,
                                ZSTD_customMem customMem)
{
    if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
    DEBUGLOG(3, "ZSTD_createCDict_advanced_internal (dictSize=%u)", (unsigned)dictSize);

    {   size_t const workspaceSize =
            ZSTD_cwksp_alloc_size(sizeof(ZSTD_CDict)) +
            ZSTD_cwksp_alloc_size(HUF_WORKSPACE_SIZE) +
            ZSTD_sizeof_matchState(&cParams, useRowMatchFinder, enableDedicatedDictSearch, /* forCCtx */ 0) +
            (dictLoadMethod == ZSTD_dlm_byRef ? 0
             : ZSTD_cwksp_alloc_size(ZSTD_cwksp_align(dictSize, sizeof(void*))));
        void* const workspace = ZSTD_customMalloc(workspaceSize, customMem);
        ZSTD_cwksp ws;
        ZSTD_CDict* cdict;

        if (!workspace) {
            ZSTD_customFree(workspace, customMem);
            return NULL;
        }

        ZSTD_cwksp_init(&ws, workspace, workspaceSize, ZSTD_cwksp_dynamic_alloc);

        cdict = (ZSTD_CDict*)ZSTD_cwksp_reserve_object(&ws, sizeof(ZSTD_CDict));
        assert(cdict != NULL);
        ZSTD_cwksp_move(&cdict->workspace, &ws);
        cdict->customMem = customMem;
        cdict->compressionLevel = ZSTD_NO_CLEVEL; /* signals advanced API usage */
        cdict->useRowMatchFinder = useRowMatchFinder;
        return cdict;
    }
}

ZSTD_CDict* ZSTD_createCDict_advanced(const void* dictBuffer, size_t dictSize,
                                      ZSTD_dictLoadMethod_e dictLoadMethod,
                                      ZSTD_dictContentType_e dictContentType,
                                      ZSTD_compressionParameters cParams,
                                      ZSTD_customMem customMem)
{
    ZSTD_CCtx_params cctxParams;
    ZSTD_memset(&cctxParams, 0, sizeof(cctxParams));
    DEBUGLOG(3, "ZSTD_createCDict_advanced, dictSize=%u, mode=%u", (unsigned)dictSize, (unsigned)dictContentType);
    ZSTD_CCtxParams_init(&cctxParams, 0);
    cctxParams.cParams = cParams;
    cctxParams.customMem = customMem;
    return ZSTD_createCDict_advanced2(
        dictBuffer, dictSize,
        dictLoadMethod, dictContentType,
        &cctxParams, customMem);
}

ZSTD_CDict* ZSTD_createCDict_advanced2(
        const void* dict, size_t dictSize,
        ZSTD_dictLoadMethod_e dictLoadMethod,
        ZSTD_dictContentType_e dictContentType,
        const ZSTD_CCtx_params* originalCctxParams,
        ZSTD_customMem customMem)
{
    ZSTD_CCtx_params cctxParams = *originalCctxParams;
    ZSTD_compressionParameters cParams;
    ZSTD_CDict* cdict;

    DEBUGLOG(3, "ZSTD_createCDict_advanced2, dictSize=%u, mode=%u", (unsigned)dictSize, (unsigned)dictContentType);
    if (!customMem.customAlloc ^ !customMem.customFree) return NULL;

    if (cctxParams.enableDedicatedDictSearch) {
        cParams = ZSTD_dedicatedDictSearch_getCParams(
            cctxParams.compressionLevel, dictSize);
        ZSTD_rust_params_overrideCParams(&cParams, &cctxParams.cParams);
    } else {
        cParams = ZSTD_getCParamsFromCCtxParams(
            &cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
    }

    if (!ZSTD_rust_params_dedicatedDictSearchIsSupported(cParams)) {
        /* Fall back to non-DDSS params */
        cctxParams.enableDedicatedDictSearch = 0;
        cParams = ZSTD_getCParamsFromCCtxParams(
            &cctxParams, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
    }

    DEBUGLOG(3, "ZSTD_createCDict_advanced2: DedicatedDictSearch=%u", cctxParams.enableDedicatedDictSearch);
    cctxParams.cParams = cParams;
    cctxParams.useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(cctxParams.useRowMatchFinder, &cParams);

    cdict = ZSTD_createCDict_advanced_internal(dictSize,
                        dictLoadMethod, cctxParams.cParams,
                        cctxParams.useRowMatchFinder, cctxParams.enableDedicatedDictSearch,
                        customMem);

    if (!cdict || ZSTD_isError( ZSTD_initCDict_internal(cdict,
                                    dict, dictSize,
                                    dictLoadMethod, dictContentType,
                                    cctxParams) )) {
        ZSTD_freeCDict(cdict);
        return NULL;
    }

    return cdict;
}

ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel)
{
    ZSTD_compressionParameters cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
    ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dict, dictSize,
                                                  ZSTD_dlm_byCopy, ZSTD_dct_auto,
                                                  cParams, ZSTD_defaultCMem);
    if (cdict)
        cdict->compressionLevel = (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT : compressionLevel;
    return cdict;
}

ZSTD_CDict* ZSTD_createCDict_byReference(const void* dict, size_t dictSize, int compressionLevel)
{
    ZSTD_compressionParameters cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, dictSize, ZSTD_cpm_createCDict);
    ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dict, dictSize,
                                     ZSTD_dlm_byRef, ZSTD_dct_auto,
                                     cParams, ZSTD_defaultCMem);
    if (cdict)
        cdict->compressionLevel = (compressionLevel == 0) ? ZSTD_CLEVEL_DEFAULT : compressionLevel;
    return cdict;
}

size_t ZSTD_freeCDict(ZSTD_CDict* cdict)
{
    if (cdict==NULL) return 0;   /* support free on NULL */
    {   ZSTD_customMem const cMem = cdict->customMem;
        int cdictInWorkspace = ZSTD_cwksp_owns_buffer(&cdict->workspace, cdict);
        ZSTD_cwksp_free(&cdict->workspace, cMem);
        if (!cdictInWorkspace) {
            ZSTD_customFree(cdict, cMem);
        }
        return 0;
    }
}

/*! ZSTD_initStaticCDict_advanced() :
 *  Generate a digested dictionary in provided memory area.
 *  workspace: The memory area to emplace the dictionary into.
 *             Provided pointer must 8-bytes aligned.
 *             It must outlive dictionary usage.
 *  workspaceSize: Use ZSTD_estimateCDictSize()
 *                 to determine how large workspace must be.
 *  cParams : use ZSTD_getCParams() to transform a compression level
 *            into its relevant cParams.
 * @return : pointer to ZSTD_CDict*, or NULL if error (size too small)
 *  Note : there is no corresponding "free" function.
 *         Since workspace was allocated externally, it must be freed externally.
 */
const ZSTD_CDict* ZSTD_initStaticCDict(
                                 void* workspace, size_t workspaceSize,
                           const void* dict, size_t dictSize,
                                 ZSTD_dictLoadMethod_e dictLoadMethod,
                                 ZSTD_dictContentType_e dictContentType,
                                 ZSTD_compressionParameters cParams)
{
    ZSTD_ParamSwitch_e const useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(ZSTD_ps_auto, &cParams);
    /* enableDedicatedDictSearch == 1 ensures matchstate is not too small in case this CDict will be used for DDS + row hash */
    size_t const matchStateSize = ZSTD_sizeof_matchState(&cParams, useRowMatchFinder, /* enableDedicatedDictSearch */ 1, /* forCCtx */ 0);
    size_t const neededSize = ZSTD_cwksp_alloc_size(sizeof(ZSTD_CDict))
                            + (dictLoadMethod == ZSTD_dlm_byRef ? 0
                               : ZSTD_cwksp_alloc_size(ZSTD_cwksp_align(dictSize, sizeof(void*))))
                            + ZSTD_cwksp_alloc_size(HUF_WORKSPACE_SIZE)
                            + matchStateSize;
    ZSTD_CDict* cdict;
    ZSTD_CCtx_params params;

    DEBUGLOG(4, "ZSTD_initStaticCDict (dictSize==%u)", (unsigned)dictSize);
    if ((size_t)workspace & 7) return NULL;  /* 8-aligned */

    {
        ZSTD_cwksp ws;
        ZSTD_cwksp_init(&ws, workspace, workspaceSize, ZSTD_cwksp_static_alloc);
        cdict = (ZSTD_CDict*)ZSTD_cwksp_reserve_object(&ws, sizeof(ZSTD_CDict));
        if (cdict == NULL) return NULL;
        ZSTD_cwksp_move(&cdict->workspace, &ws);
    }

    if (workspaceSize < neededSize) return NULL;

    ZSTD_CCtxParams_init(&params, 0);
    params.cParams = cParams;
    params.useRowMatchFinder = useRowMatchFinder;
    cdict->useRowMatchFinder = useRowMatchFinder;
    cdict->compressionLevel = ZSTD_NO_CLEVEL;

    if (ZSTD_isError( ZSTD_initCDict_internal(cdict,
                                              dict, dictSize,
                                              dictLoadMethod, dictContentType,
                                              params) ))
        return NULL;

    return cdict;
}

ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict)
{
    assert(cdict != NULL);
    return cdict->matchState.cParams;
}

/*! ZSTD_getDictID_fromCDict() :
 *  Provides the dictID of the dictionary loaded into `cdict`.
 *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
 *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
unsigned ZSTD_getDictID_fromCDict(const ZSTD_CDict* cdict)
{
    if (cdict==NULL) return 0;
    return cdict->dictID;
}

/* ZSTD_compressBegin_usingCDict_internal() :
 * Implementation of various ZSTD_compressBegin_usingCDict* functions.
 */
static size_t ZSTD_compressBegin_usingCDict_internal(
    ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict,
    ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize)
{
    ZSTD_CCtx_params cctxParams;
    DEBUGLOG(4, "ZSTD_compressBegin_usingCDict_internal");
    RETURN_ERROR_IF(cdict==NULL, dictionary_wrong, "NULL pointer!");
    /* Initialize the cctxParams from the cdict */
    {
        ZSTD_parameters params;
        params.fParams = fParams;
        params.cParams = ( pledgedSrcSize < ZSTD_USE_CDICT_PARAMS_SRCSIZE_CUTOFF
                        || pledgedSrcSize < cdict->dictContentSize * ZSTD_USE_CDICT_PARAMS_DICTSIZE_MULTIPLIER
                        || pledgedSrcSize == ZSTD_CONTENTSIZE_UNKNOWN
                        || cdict->compressionLevel == 0 ) ?
                ZSTD_getCParamsFromCDict(cdict)
              : ZSTD_getCParams(cdict->compressionLevel,
                                pledgedSrcSize,
                                cdict->dictContentSize);
        ZSTD_CCtxParams_init_internal(&cctxParams, &params, cdict->compressionLevel);
    }
    /* Increase window log to fit the entire dictionary and source if the
     * source size is known. Limit the increase to 19, which is the
     * window log for compression level 1 with the largest source size.
     */
    if (pledgedSrcSize != ZSTD_CONTENTSIZE_UNKNOWN) {
        U32 const limitedSrcSize = (U32)MIN(pledgedSrcSize, 1U << 19);
        U32 const limitedSrcLog = limitedSrcSize > 1 ? ZSTD_highbit32(limitedSrcSize - 1) + 1 : 1;
        cctxParams.cParams.windowLog = MAX(cctxParams.cParams.windowLog, limitedSrcLog);
    }
    return ZSTD_compressBegin_internal(cctx,
                                        NULL, 0, ZSTD_dct_auto, ZSTD_dtlm_fast,
                                        cdict,
                                        &cctxParams, pledgedSrcSize,
                                        ZSTDb_not_buffered);
}


/* ZSTD_compressBegin_usingCDict_advanced() :
 * This function is DEPRECATED.
 * cdict must be != NULL */
size_t ZSTD_compressBegin_usingCDict_advanced(
    ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict,
    ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize)
{
    return ZSTD_compressBegin_usingCDict_internal(cctx, cdict, fParams, pledgedSrcSize);
}

/* ZSTD_compressBegin_usingCDict() :
 * cdict must be != NULL */
size_t ZSTD_compressBegin_usingCDict_deprecated(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
{
    ZSTD_frameParameters const fParams = { 0 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
    return ZSTD_compressBegin_usingCDict_internal(cctx, cdict, fParams, ZSTD_CONTENTSIZE_UNKNOWN);
}

size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict)
{
    return ZSTD_compressBegin_usingCDict_deprecated(cctx, cdict);
}

/*! ZSTD_compress_usingCDict_internal():
 * Implementation of various ZSTD_compress_usingCDict* functions.
 */
static size_t ZSTD_compress_usingCDict_internal(ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize,
                                const ZSTD_CDict* cdict, ZSTD_frameParameters fParams)
{
    FORWARD_IF_ERROR(ZSTD_compressBegin_usingCDict_internal(cctx, cdict, fParams, srcSize), ""); /* will check if cdict != NULL */
    return ZSTD_compressEnd_public(cctx, dst, dstCapacity, src, srcSize);
}

/*! ZSTD_compress_usingCDict_advanced():
 * This function is DEPRECATED.
 */
size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize,
                                const ZSTD_CDict* cdict, ZSTD_frameParameters fParams)
{
    return ZSTD_compress_usingCDict_internal(cctx, dst, dstCapacity, src, srcSize, cdict, fParams);
}

/*! ZSTD_compress_usingCDict() :
 *  Compression using a digested Dictionary.
 *  Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
 *  Note that compression parameters are decided at CDict creation time
 *  while frame parameters are hardcoded */
size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize,
                                const ZSTD_CDict* cdict)
{
    ZSTD_frameParameters const fParams = { 1 /*content*/, 0 /*checksum*/, 0 /*noDictID*/ };
    return ZSTD_compress_usingCDict_internal(cctx, dst, dstCapacity, src, srcSize, cdict, fParams);
}



/* ******************************************************************
*  Streaming
********************************************************************/

ZSTD_CStream* ZSTD_createCStream(void)
{
    DEBUGLOG(3, "ZSTD_createCStream");
    return ZSTD_createCStream_advanced(ZSTD_defaultCMem);
}

ZSTD_CStream* ZSTD_initStaticCStream(void *workspace, size_t workspaceSize)
{
    return ZSTD_initStaticCCtx(workspace, workspaceSize);
}

ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem)
{   /* CStream and CCtx are now same object */
    return ZSTD_createCCtx_advanced(customMem);
}

size_t ZSTD_freeCStream(ZSTD_CStream* zcs)
{
    return ZSTD_freeCCtx(zcs);   /* same object */
}



/*======   Initialization   ======*/

size_t ZSTD_CStreamInSize(void)  { return ZSTD_rust_CStreamInSize(); }

size_t ZSTD_CStreamOutSize(void)
{
    return ZSTD_rust_CStreamOutSize();
}

static ZSTD_CParamMode_e ZSTD_getCParamMode(ZSTD_CDict const* cdict, ZSTD_CCtx_params const* params, U64 pledgedSrcSize)
{
    int const cdict_present = cdict != NULL;
    int const cdict_strategy = cdict_present ? cdict->matchState.cParams.strategy : 0;
    int const cdict_dedicated_search = cdict_present ? cdict->matchState.dedicatedDictSearch : 0;
    return (ZSTD_CParamMode_e)ZSTD_rust_params_getCParamMode(
            cdict_present,
            cdict_strategy,
            cdict_dedicated_search,
            pledgedSrcSize,
            (int)params->attachDictPref,
            params->forceWindow);
}

/* ZSTD_resetCStream():
 * pledgedSrcSize == 0 means "unknown" */
size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pss)
{
    /* temporary : 0 interpreted as "unknown" during transition period.
     * Users willing to specify "unknown" **must** use ZSTD_CONTENTSIZE_UNKNOWN.
     * 0 will be interpreted as "empty" in the future.
     */
    U64 const pledgedSrcSize = (pss==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
    DEBUGLOG(4, "ZSTD_resetCStream: pledgedSrcSize = %u", (unsigned)pledgedSrcSize);
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
    return 0;
}

/*! ZSTD_initCStream_internal() :
 *  Note : for lib/compress only. Used by zstdmt_compress.c.
 *  Assumption 1 : params are valid
 *  Assumption 2 : either dict, or cdict, is defined, not both */
size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
                    const void* dict, size_t dictSize, const ZSTD_CDict* cdict,
                    const ZSTD_CCtx_params* params,
                    unsigned long long pledgedSrcSize)
{
    DEBUGLOG(4, "ZSTD_initCStream_internal");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
    assert(!ZSTD_isError(ZSTD_checkCParams(params->cParams)));
    zcs->requestedParams = *params;
    assert(!((dict) && (cdict)));  /* either dict or cdict, not both */
    if (dict) {
        FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
    } else {
        /* Dictionary is cleared if !cdict */
        FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
    }
    return 0;
}

/* ZSTD_initCStream_usingCDict_advanced() :
 * same as ZSTD_initCStream_usingCDict(), with control over frame parameters */
size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
                                            const ZSTD_CDict* cdict,
                                            ZSTD_frameParameters fParams,
                                            unsigned long long pledgedSrcSize)
{
    DEBUGLOG(4, "ZSTD_initCStream_usingCDict_advanced");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
    zcs->requestedParams.fParams = fParams;
    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
    return 0;
}

/* note : cdict must outlive compression session */
size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict)
{
    DEBUGLOG(4, "ZSTD_initCStream_usingCDict");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, cdict) , "");
    return 0;
}


/* ZSTD_initCStream_advanced() :
 * pledgedSrcSize must be exact.
 * if srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN.
 * dict is loaded with default parameters ZSTD_dct_auto and ZSTD_dlm_byCopy. */
size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
                                 const void* dict, size_t dictSize,
                                 ZSTD_parameters params, unsigned long long pss)
{
    /* for compatibility with older programs relying on this behavior.
     * Users should now specify ZSTD_CONTENTSIZE_UNKNOWN.
     * This line will be removed in the future.
     */
    U64 const pledgedSrcSize = (pss==0 && params.fParams.contentSizeFlag==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
    DEBUGLOG(4, "ZSTD_initCStream_advanced");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
    FORWARD_IF_ERROR( ZSTD_checkCParams(params.cParams) , "");
    ZSTD_CCtxParams_setZstdParams(&zcs->requestedParams, &params);
    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
    return 0;
}

size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel)
{
    DEBUGLOG(4, "ZSTD_initCStream_usingDict");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_loadDictionary(zcs, dict, dictSize) , "");
    return 0;
}

size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pss)
{
    /* temporary : 0 interpreted as "unknown" during transition period.
     * Users willing to specify "unknown" **must** use ZSTD_CONTENTSIZE_UNKNOWN.
     * 0 will be interpreted as "empty" in the future.
     */
    U64 const pledgedSrcSize = (pss==0) ? ZSTD_CONTENTSIZE_UNKNOWN : pss;
    DEBUGLOG(4, "ZSTD_initCStream_srcSize");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize) , "");
    return 0;
}

size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel)
{
    DEBUGLOG(4, "ZSTD_initCStream");
    FORWARD_IF_ERROR( ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_refCDict(zcs, NULL) , "");
    FORWARD_IF_ERROR( ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel) , "");
    return 0;
}

/*======   Compression   ======*/

static size_t ZSTD_nextInputSizeHint(const ZSTD_CCtx* cctx)
{
    int const inBufferMode = (int)cctx->appliedParams.inBufferMode;
    if (inBufferMode == ZSTD_bm_stable) {
        return ZSTD_rust_nextInputSizeHint(inBufferMode,
                                           cctx->blockSizeMax,
                                           cctx->stableIn_notConsumed,
                                           cctx->inBuffTarget,
                                           cctx->inBuffPos);
    }
    assert(inBufferMode == ZSTD_bm_buffered);
    return ZSTD_rust_nextInputSizeHint(inBufferMode,
                                       cctx->blockSizeMax,
                                       cctx->stableIn_notConsumed,
                                       cctx->inBuffTarget,
                                       cctx->inBuffPos);
}

/** ZSTD_compressStream_generic():
 *  internal function for all *compressStream*() variants
 * @return : hint size for next input to complete ongoing block */
static size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
                                          ZSTD_outBuffer* output,
                                          ZSTD_inBuffer* input,
                                          ZSTD_EndDirective const flushMode)
{
    const char* const istart = (assert(input != NULL), (const char*)input->src);
    const char* const iend = (istart != NULL) ? istart + input->size : istart;
    const char* ip = (istart != NULL) ? istart + input->pos : istart;
    char* const ostart = (assert(output != NULL), (char*)output->dst);
    char* const oend = (ostart != NULL) ? ostart + output->size : ostart;
    char* op = (ostart != NULL) ? ostart + output->pos : ostart;
    U32 someMoreWork = 1;

    /* check expectations */
    DEBUGLOG(5, "ZSTD_compressStream_generic, flush=%i, srcSize = %zu", (int)flushMode, input->size - input->pos);
    assert(zcs != NULL);
    if (zcs->appliedParams.inBufferMode == ZSTD_bm_stable) {
        assert(input->pos >= zcs->stableIn_notConsumed);
        input->pos -= zcs->stableIn_notConsumed;
        if (ip) ip -= zcs->stableIn_notConsumed;
        zcs->stableIn_notConsumed = 0;
    }
    if (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered) {
        assert(zcs->inBuff != NULL);
        assert(zcs->inBuffSize > 0);
    }
    if (zcs->appliedParams.outBufferMode == ZSTD_bm_buffered) {
        assert(zcs->outBuff !=  NULL);
        assert(zcs->outBuffSize > 0);
    }
    if (input->src == NULL) assert(input->size == 0);
    assert(input->pos <= input->size);
    if (output->dst == NULL) assert(output->size == 0);
    assert(output->pos <= output->size);
    assert((U32)flushMode <= (U32)ZSTD_e_end);

    while (someMoreWork) {
        switch(zcs->streamStage)
        {
        case zcss_init:
            RETURN_ERROR(init_missing, "call ZSTD_initCStream() first!");

        case zcss_load:
            if ( (flushMode == ZSTD_e_end)
              && ( (size_t)(oend-op) >= ZSTD_compressBound((size_t)(iend-ip))     /* Enough output space */
                || zcs->appliedParams.outBufferMode == ZSTD_bm_stable)  /* OR we are allowed to return dstSizeTooSmall */
              && (zcs->inBuffPos == 0) ) {
                /* shortcut to compression pass directly into output buffer */
                size_t const cSize = ZSTD_compressEnd_public(zcs,
                                                op, (size_t)(oend-op),
                                                ip, (size_t)(iend-ip));
                DEBUGLOG(4, "ZSTD_compressEnd : cSize=%u", (unsigned)cSize);
                FORWARD_IF_ERROR(cSize, "ZSTD_compressEnd failed");
                ip = iend;
                op += cSize;
                zcs->frameEnded = 1;
                ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
                someMoreWork = 0; break;
            }
            /* complete loading into inBuffer in buffered mode */
            if (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered) {
                size_t const toLoad = zcs->inBuffTarget - zcs->inBuffPos;
                size_t const loaded = ZSTD_limitCopy(
                                        zcs->inBuff + zcs->inBuffPos, toLoad,
                                        ip, (size_t)(iend-ip));
                zcs->inBuffPos += loaded;
                if (ip) ip += loaded;
                if ( (flushMode == ZSTD_e_continue)
                  && (zcs->inBuffPos < zcs->inBuffTarget) ) {
                    /* not enough input to fill full block : stop here */
                    someMoreWork = 0; break;
                }
                if ( (flushMode == ZSTD_e_flush)
                  && (zcs->inBuffPos == zcs->inToCompress) ) {
                    /* empty */
                    someMoreWork = 0; break;
                }
            } else {
                assert(zcs->appliedParams.inBufferMode == ZSTD_bm_stable);
                if ( (flushMode == ZSTD_e_continue)
                  && ( (size_t)(iend - ip) < zcs->blockSizeMax) ) {
                    /* can't compress a full block : stop here */
                    zcs->stableIn_notConsumed = (size_t)(iend - ip);
                    ip = iend;  /* pretend to have consumed input */
                    someMoreWork = 0; break;
                }
                if ( (flushMode == ZSTD_e_flush)
                  && (ip == iend) ) {
                    /* empty */
                    someMoreWork = 0; break;
                }
            }
            /* compress current block (note : this stage cannot be stopped in the middle) */
            DEBUGLOG(5, "stream compression stage (flushMode==%u)", flushMode);
            {   int const inputBuffered = (zcs->appliedParams.inBufferMode == ZSTD_bm_buffered);
                void* cDst;
                size_t cSize;
                size_t oSize = (size_t)(oend-op);
                size_t const iSize = inputBuffered ? zcs->inBuffPos - zcs->inToCompress
                                                   : MIN((size_t)(iend - ip), zcs->blockSizeMax);
                if (oSize >= ZSTD_compressBound(iSize) || zcs->appliedParams.outBufferMode == ZSTD_bm_stable)
                    cDst = op;   /* compress into output buffer, to skip flush stage */
                else
                    cDst = zcs->outBuff, oSize = zcs->outBuffSize;
                if (inputBuffered) {
                    unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip==iend);
                    cSize = lastBlock ?
                            ZSTD_compressEnd_public(zcs, cDst, oSize,
                                        zcs->inBuff + zcs->inToCompress, iSize) :
                            ZSTD_compressContinue_public(zcs, cDst, oSize,
                                        zcs->inBuff + zcs->inToCompress, iSize);
                    FORWARD_IF_ERROR(cSize, "%s", lastBlock ? "ZSTD_compressEnd failed" : "ZSTD_compressContinue failed");
                    zcs->frameEnded = lastBlock;
                    /* prepare next block */
                    zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSizeMax;
                    if (zcs->inBuffTarget > zcs->inBuffSize)
                        zcs->inBuffPos = 0, zcs->inBuffTarget = zcs->blockSizeMax;
                    DEBUGLOG(5, "inBuffTarget:%u / inBuffSize:%u",
                            (unsigned)zcs->inBuffTarget, (unsigned)zcs->inBuffSize);
                    if (!lastBlock)
                        assert(zcs->inBuffTarget <= zcs->inBuffSize);
                    zcs->inToCompress = zcs->inBuffPos;
                } else { /* !inputBuffered, hence ZSTD_bm_stable */
                    unsigned const lastBlock = (flushMode == ZSTD_e_end) && (ip + iSize == iend);
                    cSize = lastBlock ?
                            ZSTD_compressEnd_public(zcs, cDst, oSize, ip, iSize) :
                            ZSTD_compressContinue_public(zcs, cDst, oSize, ip, iSize);
                    /* Consume the input prior to error checking to mirror buffered mode. */
                    if (ip) ip += iSize;
                    FORWARD_IF_ERROR(cSize, "%s", lastBlock ? "ZSTD_compressEnd failed" : "ZSTD_compressContinue failed");
                    zcs->frameEnded = lastBlock;
                    if (lastBlock) assert(ip == iend);
                }
                if (cDst == op) {  /* no need to flush */
                    op += cSize;
                    if (zcs->frameEnded) {
                        DEBUGLOG(5, "Frame completed directly in outBuffer");
                        someMoreWork = 0;
                        ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
                    }
                    break;
                }
                zcs->outBuffContentSize = cSize;
                zcs->outBuffFlushedSize = 0;
                zcs->streamStage = zcss_flush; /* pass-through to flush stage */
            }
	    ZSTD_FALLTHROUGH;
        case zcss_flush:
            DEBUGLOG(5, "flush stage");
            assert(zcs->appliedParams.outBufferMode == ZSTD_bm_buffered);
            {   size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
                size_t const flushed = ZSTD_limitCopy(op, (size_t)(oend-op),
                            zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
                DEBUGLOG(5, "toFlush: %u into %u ==> flushed: %u",
                            (unsigned)toFlush, (unsigned)(oend-op), (unsigned)flushed);
                if (flushed)
                    op += flushed;
                zcs->outBuffFlushedSize += flushed;
                if (toFlush!=flushed) {
                    /* flush not fully completed, presumably because dst is too small */
                    assert(op==oend);
                    someMoreWork = 0;
                    break;
                }
                zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
                if (zcs->frameEnded) {
                    DEBUGLOG(5, "Frame completed on flush");
                    someMoreWork = 0;
                    ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
                    break;
                }
                zcs->streamStage = zcss_load;
                break;
            }

        default: /* impossible */
            assert(0);
        }
    }

    input->pos = (size_t)(ip - istart);
    output->pos = (size_t)(op - ostart);
    if (zcs->frameEnded) return 0;
    return ZSTD_nextInputSizeHint(zcs);
}

static size_t ZSTD_nextInputSizeHint_MTorST(const ZSTD_CCtx* cctx)
{
#ifdef ZSTD_MULTITHREAD
    if (cctx->appliedParams.nbWorkers >= 1) {
        assert(cctx->mtctx != NULL);
        return ZSTDMT_nextInputSizeHint(cctx->mtctx);
    }
#endif
    return ZSTD_nextInputSizeHint(cctx);

}

size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{
    FORWARD_IF_ERROR( ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue) , "");
    return ZSTD_nextInputSizeHint_MTorST(zcs);
}

/* After a compression call set the expected input/output buffer.
 * This is validated at the start of the next compression call.
 */
static void
ZSTD_setBufferExpectations(ZSTD_CCtx* cctx, const ZSTD_outBuffer* output, const ZSTD_inBuffer* input)
{
    DEBUGLOG(5, "ZSTD_setBufferExpectations (for advanced stable in/out modes)");
    if (cctx->appliedParams.inBufferMode == ZSTD_bm_stable) {
        cctx->expectedInBuffer = *input;
    }
    if (cctx->appliedParams.outBufferMode == ZSTD_bm_stable) {
        cctx->expectedOutBufferSize = output->size - output->pos;
    }
}

/* Validate that the input/output buffers match the expectations set by
 * ZSTD_setBufferExpectations.
 */
static size_t ZSTD_checkBufferStability(ZSTD_CCtx const* cctx,
                                        ZSTD_outBuffer const* output,
                                        ZSTD_inBuffer const* input)
{
    return ZSTD_rust_checkBufferStability(
            (int)cctx->appliedParams.inBufferMode,
            (int)cctx->appliedParams.outBufferMode,
            cctx->expectedInBuffer.src,
            cctx->expectedInBuffer.pos,
            input->src,
            input->pos,
            cctx->expectedOutBufferSize,
            output->size,
            output->pos);
}

/*
 * If @endOp == ZSTD_e_end, @inSize becomes pledgedSrcSize.
 * Otherwise, it's ignored.
 * @return: 0 on success, or a ZSTD_error code otherwise.
 */
static size_t ZSTD_CCtx_init_compressStream2(ZSTD_CCtx* cctx,
                                             ZSTD_EndDirective endOp,
                                             size_t inSize)
{
    ZSTD_CCtx_params params = cctx->requestedParams;
    ZSTD_prefixDict const prefixDict = cctx->prefixDict;
    FORWARD_IF_ERROR( ZSTD_initLocalDict(cctx) , ""); /* Init the local dict if present. */
    ZSTD_memset(&cctx->prefixDict, 0, sizeof(cctx->prefixDict));   /* single usage */
    assert(prefixDict.dict==NULL || cctx->cdict==NULL);    /* only one can be set */
    if (cctx->cdict && !cctx->localDict.cdict) {
        /* Let the cdict's compression level take priority over the requested params.
         * But do not take the cdict's compression level if the "cdict" is actually a localDict
         * generated from ZSTD_initLocalDict().
         */
        params.compressionLevel = cctx->cdict->compressionLevel;
    }
    DEBUGLOG(4, "ZSTD_CCtx_init_compressStream2 : transparent init stage");
    if (endOp == ZSTD_e_end) cctx->pledgedSrcSizePlusOne = inSize + 1;  /* auto-determine pledgedSrcSize */

    {   size_t const dictSize = prefixDict.dict
                ? prefixDict.dictSize
                : (cctx->cdict ? cctx->cdict->dictContentSize : 0);
        ZSTD_CParamMode_e const mode = ZSTD_getCParamMode(cctx->cdict, &params, cctx->pledgedSrcSizePlusOne - 1);
        params.cParams = ZSTD_getCParamsFromCCtxParams(
                &params, cctx->pledgedSrcSizePlusOne-1,
                dictSize, mode);
    }

    params.postBlockSplitter = ZSTD_resolveBlockSplitterMode(params.postBlockSplitter, &params.cParams);
    params.ldmParams.enableLdm = ZSTD_resolveEnableLdm(params.ldmParams.enableLdm, &params.cParams);
    params.useRowMatchFinder = ZSTD_resolveRowMatchFinderMode(params.useRowMatchFinder, &params.cParams);
    params.validateSequences = ZSTD_resolveExternalSequenceValidation(params.validateSequences);
    params.maxBlockSize = ZSTD_resolveMaxBlockSize(params.maxBlockSize);
    params.searchForExternalRepcodes = ZSTD_resolveExternalRepcodeSearch(params.searchForExternalRepcodes, params.compressionLevel);

#ifdef ZSTD_MULTITHREAD
    /* If external matchfinder is enabled, make sure to fail before checking job size (for consistency) */
    RETURN_ERROR_IF(
        ZSTD_hasExtSeqProd(&params) && params.nbWorkers >= 1,
        parameter_combination_unsupported,
        "External sequence producer isn't supported with nbWorkers >= 1"
    );

    if ((cctx->pledgedSrcSizePlusOne-1) <= ZSTDMT_JOBSIZE_MIN) {
        params.nbWorkers = 0; /* do not invoke multi-threading when src size is too small */
    }
    if (params.nbWorkers > 0) {
# if ZSTD_TRACE
        cctx->traceCtx = (ZSTD_trace_compress_begin != NULL) ? ZSTD_trace_compress_begin(cctx) : 0;
# endif
        /* mt context creation */
        if (cctx->mtctx == NULL) {
            DEBUGLOG(4, "ZSTD_compressStream2: creating new mtctx for nbWorkers=%u",
                        params.nbWorkers);
            cctx->mtctx = ZSTDMT_createCCtx_advanced((U32)params.nbWorkers, cctx->customMem, cctx->pool);
            RETURN_ERROR_IF(cctx->mtctx == NULL, memory_allocation, "NULL pointer!");
        }
        /* mt compression */
        DEBUGLOG(4, "call ZSTDMT_initCStream_internal as nbWorkers=%u", params.nbWorkers);
        FORWARD_IF_ERROR( ZSTDMT_initCStream_internal(
                    cctx->mtctx,
                    prefixDict.dict, prefixDict.dictSize, prefixDict.dictContentType,
                    cctx->cdict, params, cctx->pledgedSrcSizePlusOne-1) , "");
        cctx->dictID = cctx->cdict ? cctx->cdict->dictID : 0;
        cctx->dictContentSize = cctx->cdict ? cctx->cdict->dictContentSize : prefixDict.dictSize;
        cctx->consumedSrcSize = 0;
        cctx->producedCSize = 0;
        cctx->streamStage = zcss_load;
        cctx->appliedParams = params;
    } else
#endif  /* ZSTD_MULTITHREAD */
    {   U64 const pledgedSrcSize = cctx->pledgedSrcSizePlusOne - 1;
        assert(!ZSTD_isError(ZSTD_checkCParams(params.cParams)));
        FORWARD_IF_ERROR( ZSTD_compressBegin_internal(cctx,
                prefixDict.dict, prefixDict.dictSize, prefixDict.dictContentType, ZSTD_dtlm_fast,
                cctx->cdict,
                &params, pledgedSrcSize,
                ZSTDb_buffered) , "");
        assert(cctx->appliedParams.nbWorkers == 0);
        cctx->inToCompress = 0;
        cctx->inBuffPos = 0;
        if (cctx->appliedParams.inBufferMode == ZSTD_bm_buffered) {
            /* for small input: avoid automatic flush on reaching end of block, since
            * it would require to add a 3-bytes null block to end frame
            */
            cctx->inBuffTarget = cctx->blockSizeMax + (cctx->blockSizeMax == pledgedSrcSize);
        } else {
            cctx->inBuffTarget = 0;
        }
        cctx->outBuffContentSize = cctx->outBuffFlushedSize = 0;
        cctx->streamStage = zcss_load;
        cctx->frameEnded = 0;
    }
    return 0;
}

/* @return provides a minimum amount of data remaining to be flushed from internal buffers
 */
size_t ZSTD_compressStream2_c( ZSTD_CCtx* cctx,
                               ZSTD_outBuffer* output,
                               ZSTD_inBuffer* input,
                               ZSTD_EndDirective endOp)
{
    DEBUGLOG(5, "ZSTD_compressStream2, endOp=%u ", (unsigned)endOp);
    /* check conditions */
    RETURN_ERROR_IF(output->pos > output->size, dstSize_tooSmall, "invalid output buffer");
    RETURN_ERROR_IF(input->pos  > input->size, srcSize_wrong, "invalid input buffer");
    RETURN_ERROR_IF((U32)endOp > (U32)ZSTD_e_end, parameter_outOfBound, "invalid endDirective");
    assert(cctx != NULL);

    /* transparent initialization stage */
    if (cctx->rustSimpleCompress2Completed) {
        if (endOp == ZSTD_e_end
            && cctx->streamStage == zcss_init
            && cctx->pledgedSrcSizePlusOne == 0
            && ZSTD_rust_simpleCompress2Level(
                    cctx, input->size - input->pos) != (-2147483647 - 1)) {
            void* const dst = output->dst ?
                    (char*)output->dst + output->pos : output->dst;
            const void* const src = input->src ?
                    (const char*)input->src + input->pos : input->src;
            size_t const result = ZSTD_compress2(
                    cctx, dst, output->size - output->pos,
                    src, input->size - input->pos);
            cctx->rustSimpleCompress2Completed = 0;
            if (!ZSTD_isError(result)) {
                output->pos += result;
                input->pos = input->size;
                return 0;
            }
        }
        /* A different streaming directive or an advanced parameter means the
         * frame can no longer reuse the one-shot Rust result. */
        cctx->rustSimpleCompress2Completed = 0;
    }

    if (cctx->streamStage == zcss_init) {
        size_t const inputSize = input->size - input->pos;  /* no obligation to start from pos==0 */
        size_t const totalInputSize = inputSize + cctx->stableIn_notConsumed;
        if ( (cctx->requestedParams.inBufferMode == ZSTD_bm_stable) /* input is presumed stable, across invocations */
          && (endOp == ZSTD_e_continue)                             /* no flush requested, more input to come */
          && (totalInputSize < ZSTD_BLOCKSIZE_MAX) ) {              /* not even reached one block yet */
            if (cctx->stableIn_notConsumed) {  /* not the first time */
                /* check stable source guarantees */
                RETURN_ERROR_IF(input->src != cctx->expectedInBuffer.src, stabilityCondition_notRespected, "stableInBuffer condition not respected: wrong src pointer");
                RETURN_ERROR_IF(input->pos != cctx->expectedInBuffer.size, stabilityCondition_notRespected, "stableInBuffer condition not respected: externally modified pos");
            }
            /* pretend input was consumed, to give a sense forward progress */
            input->pos = input->size;
            /* save stable inBuffer, for later control, and flush/end */
            cctx->expectedInBuffer = *input;
            /* but actually input wasn't consumed, so keep track of position from where compression shall resume */
            cctx->stableIn_notConsumed += inputSize;
            /* don't initialize yet, wait for the first block of flush() order, for better parameters adaptation */
            return ZSTD_FRAMEHEADERSIZE_MIN(cctx->requestedParams.format);  /* at least some header to produce */
        }
        FORWARD_IF_ERROR(ZSTD_CCtx_init_compressStream2(cctx, endOp, totalInputSize), "compressStream2 initialization failed");
        ZSTD_setBufferExpectations(cctx, output, input);   /* Set initial buffer expectations now that we've initialized */
    }
    /* end of transparent initialization stage */

    FORWARD_IF_ERROR(ZSTD_checkBufferStability(cctx, output, input), "invalid buffers");
    /* compression stage */
#ifdef ZSTD_MULTITHREAD
    if (cctx->appliedParams.nbWorkers > 0) {
        size_t flushMin;
        if (cctx->cParamsChanged) {
            ZSTDMT_updateCParams_whileCompressing(cctx->mtctx, &cctx->requestedParams);
            cctx->cParamsChanged = 0;
        }
        if (cctx->stableIn_notConsumed) {
            assert(cctx->appliedParams.inBufferMode == ZSTD_bm_stable);
            /* some early data was skipped - make it available for consumption */
            assert(input->pos >= cctx->stableIn_notConsumed);
            input->pos -= cctx->stableIn_notConsumed;
            cctx->stableIn_notConsumed = 0;
        }
        for (;;) {
            size_t const ipos = input->pos;
            size_t const opos = output->pos;
            flushMin = ZSTDMT_compressStream_generic(cctx->mtctx, output, input, endOp);
            cctx->consumedSrcSize += (U64)(input->pos - ipos);
            cctx->producedCSize += (U64)(output->pos - opos);
            if ( ZSTD_isError(flushMin)
              || (endOp == ZSTD_e_end && flushMin == 0) ) { /* compression completed */
                if (flushMin == 0)
                    ZSTD_CCtx_trace(cctx, 0);
                ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
            }
            FORWARD_IF_ERROR(flushMin, "ZSTDMT_compressStream_generic failed");

            if (endOp == ZSTD_e_continue) {
                /* We only require some progress with ZSTD_e_continue, not maximal progress.
                 * We're done if we've consumed or produced any bytes, or either buffer is
                 * full.
                 */
                if (input->pos != ipos || output->pos != opos || input->pos == input->size || output->pos == output->size)
                    break;
            } else {
                assert(endOp == ZSTD_e_flush || endOp == ZSTD_e_end);
                /* We require maximal progress. We're done when the flush is complete or the
                 * output buffer is full.
                 */
                if (flushMin == 0 || output->pos == output->size)
                    break;
            }
        }
        DEBUGLOG(5, "completed ZSTD_compressStream2 delegating to ZSTDMT_compressStream_generic");
        /* Either we don't require maximum forward progress, we've finished the
         * flush, or we are out of output space.
         */
        assert(endOp == ZSTD_e_continue || flushMin == 0 || output->pos == output->size);
        ZSTD_setBufferExpectations(cctx, output, input);
        return flushMin;
    }
#endif /* ZSTD_MULTITHREAD */
    FORWARD_IF_ERROR( ZSTD_compressStream_generic(cctx, output, input, endOp) , "");
    DEBUGLOG(5, "completed ZSTD_compressStream2");
    ZSTD_setBufferExpectations(cctx, output, input);
    return cctx->outBuffContentSize - cctx->outBuffFlushedSize; /* remaining to flush */
}

size_t ZSTD_compressStream2_simpleArgs (
                            ZSTD_CCtx* cctx,
                            void* dst, size_t dstCapacity, size_t* dstPos,
                      const void* src, size_t srcSize, size_t* srcPos,
                            ZSTD_EndDirective endOp)
{
    ZSTD_outBuffer output;
    ZSTD_inBuffer  input;
    output.dst = dst;
    output.size = dstCapacity;
    output.pos = *dstPos;
    input.src = src;
    input.size = srcSize;
    input.pos = *srcPos;
    /* ZSTD_compressStream2() will check validity of dstPos and srcPos */
    {   size_t const cErr = ZSTD_compressStream2(cctx, &output, &input, endOp);
        *dstPos = output.pos;
        *srcPos = input.pos;
        return cErr;
    }
}

size_t ZSTD_compress2_c(ZSTD_CCtx* cctx,
                        void* dst, size_t dstCapacity,
                        const void* src, size_t srcSize)
{
    ZSTD_bufferMode_e const originalInBufferMode = cctx->requestedParams.inBufferMode;
    ZSTD_bufferMode_e const originalOutBufferMode = cctx->requestedParams.outBufferMode;
    DEBUGLOG(4, "ZSTD_compress2 (srcSize=%u)", (unsigned)srcSize);
    ZSTD_CCtx_reset(cctx, ZSTD_reset_session_only);
    /* Enable stable input/output buffers. */
    cctx->requestedParams.inBufferMode = ZSTD_bm_stable;
    cctx->requestedParams.outBufferMode = ZSTD_bm_stable;
    {   size_t oPos = 0;
        size_t iPos = 0;
        size_t const result = ZSTD_compressStream2_simpleArgs(cctx,
                                        dst, dstCapacity, &oPos,
                                        src, srcSize, &iPos,
                                        ZSTD_e_end);
        /* Reset to the original values. */
        cctx->requestedParams.inBufferMode = originalInBufferMode;
        cctx->requestedParams.outBufferMode = originalOutBufferMode;

        FORWARD_IF_ERROR(result, "ZSTD_compressStream2_simpleArgs failed");
        if (result != 0) {  /* compression not completed, due to lack of output space */
            assert(oPos == dstCapacity);
            RETURN_ERROR(dstSize_tooSmall, "");
        }
        assert(iPos == srcSize);   /* all input is expected consumed */
        return oPos;
    }
}

/* Returns an offset code, given a sequence's raw offset, the ongoing repcode array, and whether litLength == 0 */
static U32 ZSTD_finalizeOffBase(U32 rawOffset, const U32 rep[ZSTD_REP_NUM], U32 ll0)
{
    return ZSTD_rust_finalizeOffBase(rawOffset, rep, ll0);
}

/* The explicit-delimiter adapter is also used by the external sequence
 * producer path.  Keep that C-context-facing call site separate from the
 * Rust-owned compressSequences block loop. */
static size_t
ZSTD_transferSequences_wBlockDelim(ZSTD_CCtx* cctx,
                                   ZSTD_SequencePosition* seqPos,
                             const ZSTD_Sequence* const inSeqs, size_t inSeqsSize,
                             const void* src, size_t blockSize,
                                   ZSTD_ParamSwitch_e externalRepSearch)
{
    U32 dictSize;

    if (cctx->cdict) {
        dictSize = (U32)cctx->cdict->dictContentSize;
    } else if (cctx->prefixDict.dict) {
        dictSize = (U32)cctx->prefixDict.dictSize;
    } else {
        dictSize = 0;
    }
    return ZSTD_rust_transferSequencesWBlockDelim(
            &cctx->seqStore, seqPos, inSeqs, inSeqsSize,
            (const BYTE*)src, blockSize, (int)externalRepSearch,
            cctx->blockState.prevCBlock->rep,
            cctx->blockState.nextCBlock->rep, dictSize,
            cctx->appliedParams.validateSequences,
            cctx->appliedParams.cParams.minMatch,
            cctx->appliedParams.cParams.windowLog,
            ZSTD_hasExtSeqProd(&cctx->appliedParams));
}

/* Compress all provided sequences, block-by-block.
 *
 * Returns the cumulative size of all compressed blocks (including their headers),
 * otherwise a ZSTD error.
 */
static size_t
ZSTD_compressSequences_internal(ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                          const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
                          const void* src, size_t srcSize)
{
    U32 dictSize;
    ZSTD_rust_sequenceCompressionState state;

    if (cctx->cdict) {
        dictSize = (U32)cctx->cdict->dictContentSize;
    } else if (cctx->prefixDict.dict) {
        dictSize = (U32)cctx->prefixDict.dictSize;
    } else {
        dictSize = 0;
    }

    state.seqStore = &cctx->seqStore;
    state.prevCBlock = &cctx->blockState.prevCBlock;
    state.nextCBlock = &cctx->blockState.nextCBlock;
    state.tmpWorkspace = cctx->tmpWorkspace;
    state.tmpWkspSize = cctx->tmpWkspSize;
    state.blockSizeMax = cctx->blockSizeMax;
    state.bmi2 = cctx->bmi2;
    state.blockDelimiters = (int)cctx->appliedParams.blockDelimiters;
    state.strategy = (int)cctx->appliedParams.cParams.strategy;
    state.disableLiteralCompression = ZSTD_literalsCompressionIsDisabled(&cctx->appliedParams);
    state.searchForExternalRepcodes = (int)cctx->appliedParams.searchForExternalRepcodes;
    state.validateSequences = cctx->appliedParams.validateSequences;
    state.minMatch = cctx->appliedParams.cParams.minMatch;
    state.windowLog = cctx->appliedParams.cParams.windowLog;
    state.dictSize = dictSize;
    state.useSequenceProducer = ZSTD_hasExtSeqProd(&cctx->appliedParams);
    state.isFirstBlock = &cctx->isFirstBlock;

    DEBUGLOG(4, "ZSTD_compressSequences_internal srcSize: %zu, inSeqsSize: %zu", srcSize, inSeqsSize);
    return ZSTD_rust_compressSequencesInternal(&state, dst, dstCapacity,
                                                inSeqs, inSeqsSize, src, srcSize);
}

size_t ZSTD_compressSequences(ZSTD_CCtx* cctx,
                              void* dst, size_t dstCapacity,
                              const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
                              const void* src, size_t srcSize)
{
    BYTE* op = (BYTE*)dst;
    size_t cSize = 0;

    /* Transparent initialization stage, same as compressStream2() */
    DEBUGLOG(4, "ZSTD_compressSequences (nbSeqs=%zu,dstCapacity=%zu)", inSeqsSize, dstCapacity);
    assert(cctx != NULL);
    FORWARD_IF_ERROR(ZSTD_CCtx_init_compressStream2(cctx, ZSTD_e_end, srcSize), "CCtx initialization failed");

    /* Begin writing output, starting with frame header */
    {   size_t const frameHeaderSize = ZSTD_writeFrameHeader(op, dstCapacity,
                    &cctx->appliedParams, srcSize, cctx->dictID);
        op += frameHeaderSize;
        assert(frameHeaderSize <= dstCapacity);
        dstCapacity -= frameHeaderSize;
        cSize += frameHeaderSize;
    }
    if (cctx->appliedParams.fParams.checksumFlag && srcSize) {
        XXH64_update(&cctx->xxhState, src, srcSize);
    }

    /* Now generate compressed blocks */
    {   size_t const cBlocksSize = ZSTD_compressSequences_internal(cctx,
                                                           op, dstCapacity,
                                                           inSeqs, inSeqsSize,
                                                           src, srcSize);
        FORWARD_IF_ERROR(cBlocksSize, "Compressing blocks failed!");
        cSize += cBlocksSize;
        assert(cBlocksSize <= dstCapacity);
        dstCapacity -= cBlocksSize;
    }

    /* Complete with frame checksum, if needed */
    if (cctx->appliedParams.fParams.checksumFlag) {
        U32 const checksum = (U32) XXH64_digest(&cctx->xxhState);
        RETURN_ERROR_IF(dstCapacity<4, dstSize_tooSmall, "no room for checksum");
        DEBUGLOG(4, "Write checksum : %08X", (unsigned)checksum);
        MEM_writeLE32((char*)dst + cSize, checksum);
        cSize += 4;
    }

    DEBUGLOG(4, "Final compressed size: %zu", cSize);
    return cSize;
}

/* Sequence conversion is implemented in Rust; this wrapper keeps the
 * existing C-side block orchestration and long-length bookkeeping intact. */
static size_t convertSequences_noRepcodes(
    SeqDef* dstSeqs,
    const ZSTD_Sequence* inSeqs,
    size_t nbSequences)
{
    return ZSTD_rust_convertSequencesNoRepcodes(dstSeqs, inSeqs, nbSequences);
}

/*
 * Precondition: Sequences must end on an explicit Block Delimiter
 * @return: 0 on success, or an error code.
 * Note: Sequence validation functionality has been disabled (removed).
 * This is helpful to generate a lean main pipeline, improving performance.
 * It may be re-inserted later.
 */
size_t ZSTD_convertBlockSequences(ZSTD_CCtx* cctx,
                const ZSTD_Sequence* const inSeqs, size_t nbSequences,
                int repcodeResolution)
{
    Repcodes_t updatedRepcodes;
    size_t seqNb = 0;

    DEBUGLOG(5, "ZSTD_convertBlockSequences (nbSequences = %zu)", nbSequences);

    RETURN_ERROR_IF(nbSequences >= cctx->seqStore.maxNbSeq, externalSequences_invalid,
                    "Not enough memory allocated. Try adjusting ZSTD_c_minMatch.");

    ZSTD_memcpy(updatedRepcodes.rep, cctx->blockState.prevCBlock->rep, sizeof(Repcodes_t));

    /* check end condition */
    assert(nbSequences >= 1);
    assert(inSeqs[nbSequences-1].matchLength == 0);
    assert(inSeqs[nbSequences-1].offset == 0);

    /* Convert Sequences from public format to internal format */
    if (!repcodeResolution) {
        size_t const longl = convertSequences_noRepcodes(cctx->seqStore.sequencesStart, inSeqs, nbSequences-1);
        cctx->seqStore.sequences = cctx->seqStore.sequencesStart + nbSequences-1;
        if (longl) {
            DEBUGLOG(5, "long length");
            assert(cctx->seqStore.longLengthType == ZSTD_llt_none);
            if (longl <= nbSequences-1) {
                DEBUGLOG(5, "long match length detected at pos %zu", longl-1);
                cctx->seqStore.longLengthType = ZSTD_llt_matchLength;
                cctx->seqStore.longLengthPos = (U32)(longl-1);
            } else {
                DEBUGLOG(5, "long literals length detected at pos %zu", longl-nbSequences);
                assert(longl <= 2* (nbSequences-1));
                cctx->seqStore.longLengthType = ZSTD_llt_literalLength;
                cctx->seqStore.longLengthPos = (U32)(longl-(nbSequences-1)-1);
            }
        }
    } else {
        for (seqNb = 0; seqNb < nbSequences - 1 ; seqNb++) {
            U32 const litLength = inSeqs[seqNb].litLength;
            U32 const matchLength = inSeqs[seqNb].matchLength;
            U32 const ll0 = (litLength == 0);
            U32 const offBase = ZSTD_finalizeOffBase(inSeqs[seqNb].offset, updatedRepcodes.rep, ll0);

            DEBUGLOG(6, "Storing sequence: (of: %u, ml: %u, ll: %u)", offBase, matchLength, litLength);
            ZSTD_storeSeqOnly(&cctx->seqStore, litLength, offBase, matchLength);
            ZSTD_updateRep(updatedRepcodes.rep, offBase, ll0);
        }
    }

    /* If we skipped repcode search while parsing, we need to update repcodes now */
    if (!repcodeResolution && nbSequences > 1) {
        U32* const rep = updatedRepcodes.rep;

        if (nbSequences >= 4) {
            U32 lastSeqIdx = (U32)nbSequences - 2; /* index of last full sequence */
            rep[2] = inSeqs[lastSeqIdx - 2].offset;
            rep[1] = inSeqs[lastSeqIdx - 1].offset;
            rep[0] = inSeqs[lastSeqIdx].offset;
        } else if (nbSequences == 3) {
            rep[2] = rep[0];
            rep[1] = inSeqs[0].offset;
            rep[0] = inSeqs[1].offset;
        } else {
            assert(nbSequences == 2);
            rep[2] = rep[1];
            rep[1] = rep[0];
            rep[0] = inSeqs[0].offset;
        }
    }

    ZSTD_memcpy(cctx->blockState.nextCBlock->rep, updatedRepcodes.rep, sizeof(Repcodes_t));

    return 0;
}

BlockSummary ZSTD_get1BlockSummary(const ZSTD_Sequence* seqs, size_t nbSeqs)
{
    return ZSTD_rust_get1BlockSummary(seqs, nbSeqs);
}


static size_t
ZSTD_compressSequencesAndLiterals_internal(ZSTD_CCtx* cctx,
                                void* dst, size_t dstCapacity,
                          const ZSTD_Sequence* inSeqs, size_t nbSequences,
                          const void* literals, size_t litSize, size_t srcSize)
{
    size_t remaining = srcSize;
    size_t cSize = 0;
    BYTE* op = (BYTE*)dst;
    int const repcodeResolution = (cctx->appliedParams.searchForExternalRepcodes == ZSTD_ps_enable);
    assert(cctx->appliedParams.searchForExternalRepcodes != ZSTD_ps_auto);

    DEBUGLOG(4, "ZSTD_compressSequencesAndLiterals_internal: nbSeqs=%zu, litSize=%zu", nbSequences, litSize);
    RETURN_ERROR_IF(nbSequences == 0, externalSequences_invalid, "Requires at least 1 end-of-block");

    /* Special case: empty frame */
    if ((nbSequences == 1) && (inSeqs[0].litLength == 0)) {
        U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw)<<1);
        RETURN_ERROR_IF(dstCapacity<3, dstSize_tooSmall, "No room for empty frame block header");
        MEM_writeLE24(op, cBlockHeader24);
        op += ZSTD_blockHeaderSize;
        dstCapacity -= ZSTD_blockHeaderSize;
        cSize += ZSTD_blockHeaderSize;
    }

    while (nbSequences) {
        size_t compressedSeqsSize, cBlockSize, conversionStatus;
        BlockSummary const block = ZSTD_get1BlockSummary(inSeqs, nbSequences);
        U32 const lastBlock = (block.nbSequences == nbSequences);
        FORWARD_IF_ERROR(block.nbSequences, "Error while trying to determine nb of sequences for a block");
        assert(block.nbSequences <= nbSequences);
        RETURN_ERROR_IF(block.litSize > litSize, externalSequences_invalid, "discrepancy: Sequences require more literals than present in buffer");
        ZSTD_resetSeqStore(&cctx->seqStore);

        conversionStatus = ZSTD_convertBlockSequences(cctx,
                            inSeqs, block.nbSequences,
                            repcodeResolution);
        FORWARD_IF_ERROR(conversionStatus, "Bad sequence conversion");
        inSeqs += block.nbSequences;
        nbSequences -= block.nbSequences;
        remaining -= block.blockSize;

        /* Note: when blockSize is very small, other variant send it uncompressed.
         * Here, we still send the sequences, because we don't have the original source to send it uncompressed.
         * One could imagine in theory reproducing the source from the sequences,
         * but that's complex and costly memory intensive, and goes against the objectives of this variant. */

        RETURN_ERROR_IF(dstCapacity < ZSTD_blockHeaderSize, dstSize_tooSmall, "not enough dstCapacity to write a new compressed block");

        compressedSeqsSize = ZSTD_entropyCompressSeqStore_internal(
                                op + ZSTD_blockHeaderSize /* Leave space for block header */, dstCapacity - ZSTD_blockHeaderSize,
                                literals, block.litSize,
                                &cctx->seqStore,
                                &cctx->blockState.prevCBlock->entropy, &cctx->blockState.nextCBlock->entropy,
                                &cctx->appliedParams,
                                cctx->tmpWorkspace, cctx->tmpWkspSize /* statically allocated in resetCCtx */,
                                cctx->bmi2);
        FORWARD_IF_ERROR(compressedSeqsSize, "Compressing sequences of block failed");
        /* note: the spec forbids for any compressed block to be larger than maximum block size */
        if (compressedSeqsSize > cctx->blockSizeMax) compressedSeqsSize = 0;
        DEBUGLOG(5, "Compressed sequences size: %zu", compressedSeqsSize);
        litSize -= block.litSize;
        literals = (const char*)literals + block.litSize;

        /* Note: difficult to check source for RLE block when only Literals are provided,
         * but it could be considered from analyzing the sequence directly */

        if (compressedSeqsSize == 0) {
            /* Sending uncompressed blocks is out of reach, because the source is not provided.
             * In theory, one could use the sequences to regenerate the source, like a decompressor,
             * but it's complex, and memory hungry, killing the purpose of this variant.
             * Current outcome: generate an error code.
             */
            RETURN_ERROR(cannotProduce_uncompressedBlock, "ZSTD_compressSequencesAndLiterals cannot generate an uncompressed block");
        } else {
            assert(compressedSeqsSize > 1); /* no RLE */
            /* Error checking and repcodes update */
            ZSTD_blockState_confirmRepcodesAndEntropyTables(&cctx->blockState);
            if (cctx->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
                cctx->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;

            /* Write block header into beginning of block*/
            ZSTD_rust_writeBlockHeader(op, compressedSeqsSize, block.blockSize, lastBlock);
            cBlockSize = ZSTD_blockHeaderSize + compressedSeqsSize;
            DEBUGLOG(5, "Writing out compressed block, size: %zu", cBlockSize);
        }

        cSize += cBlockSize;
        op += cBlockSize;
        dstCapacity -= cBlockSize;
        cctx->isFirstBlock = 0;
        DEBUGLOG(5, "cSize running total: %zu (remaining dstCapacity=%zu)", cSize, dstCapacity);

        if (lastBlock) {
            assert(nbSequences == 0);
            break;
        }
    }

    RETURN_ERROR_IF(litSize != 0, externalSequences_invalid, "literals must be entirely and exactly consumed");
    RETURN_ERROR_IF(remaining != 0, externalSequences_invalid, "Sequences must represent a total of exactly srcSize=%zu", srcSize);
    DEBUGLOG(4, "cSize final total: %zu", cSize);
    return cSize;
}

size_t
ZSTD_compressSequencesAndLiterals(ZSTD_CCtx* cctx,
                    void* dst, size_t dstCapacity,
                    const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
                    const void* literals, size_t litSize, size_t litCapacity,
                    size_t decompressedSize)
{
    BYTE* op = (BYTE*)dst;
    size_t cSize = 0;

    /* Transparent initialization stage, same as compressStream2() */
    DEBUGLOG(4, "ZSTD_compressSequencesAndLiterals (dstCapacity=%zu)", dstCapacity);
    assert(cctx != NULL);
    if (litCapacity < litSize) {
        RETURN_ERROR(workSpace_tooSmall, "literals buffer is not large enough: must be at least 8 bytes larger than litSize (risk of read out-of-bound)");
    }
    FORWARD_IF_ERROR(ZSTD_CCtx_init_compressStream2(cctx, ZSTD_e_end, decompressedSize), "CCtx initialization failed");

    if (cctx->appliedParams.blockDelimiters == ZSTD_sf_noBlockDelimiters) {
        RETURN_ERROR(frameParameter_unsupported, "This mode is only compatible with explicit delimiters");
    }
    if (cctx->appliedParams.validateSequences) {
        RETURN_ERROR(parameter_unsupported, "This mode is not compatible with Sequence validation");
    }
    if (cctx->appliedParams.fParams.checksumFlag) {
        RETURN_ERROR(frameParameter_unsupported, "this mode is not compatible with frame checksum");
    }

    /* Begin writing output, starting with frame header */
    {   size_t const frameHeaderSize = ZSTD_writeFrameHeader(op, dstCapacity,
                    &cctx->appliedParams, decompressedSize, cctx->dictID);
        op += frameHeaderSize;
        assert(frameHeaderSize <= dstCapacity);
        dstCapacity -= frameHeaderSize;
        cSize += frameHeaderSize;
    }

    /* Now generate compressed blocks */
    {   size_t const cBlocksSize = ZSTD_compressSequencesAndLiterals_internal(cctx,
                                            op, dstCapacity,
                                            inSeqs, inSeqsSize,
                                            literals, litSize, decompressedSize);
        FORWARD_IF_ERROR(cBlocksSize, "Compressing blocks failed!");
        cSize += cBlocksSize;
        assert(cBlocksSize <= dstCapacity);
        dstCapacity -= cBlocksSize;
    }

    DEBUGLOG(4, "Final compressed size: %zu", cSize);
    return cSize;
}

/*======   Finalize   ======*/

static ZSTD_inBuffer inBuffer_forEndFlush(const ZSTD_CStream* zcs)
{
    return ZSTD_rust_inBufferForEndFlush(zcs->appliedParams.inBufferMode,
                                         zcs->expectedInBuffer.src,
                                         zcs->expectedInBuffer.size,
                                         zcs->expectedInBuffer.pos);
}

/*! ZSTD_flushStream() :
 * @return : amount of data remaining to flush */
size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output)
{
    ZSTD_inBuffer input = inBuffer_forEndFlush(zcs);
    input.size = input.pos; /* do not ingest more input during flush */
    return ZSTD_compressStream2(zcs, output, &input, ZSTD_e_flush);
}

size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output)
{
    ZSTD_inBuffer input = inBuffer_forEndFlush(zcs);
    size_t const remainingToFlush = ZSTD_compressStream2(zcs, output, &input, ZSTD_e_end);
    FORWARD_IF_ERROR(remainingToFlush , "ZSTD_compressStream2(,,ZSTD_e_end) failed");
    if (zcs->appliedParams.nbWorkers > 0) return remainingToFlush;   /* minimal estimation */
    /* single thread mode : attempt to calculate remaining to flush more precisely */
    {   size_t const toFlush = ZSTD_rust_endStreamRemaining(
                remainingToFlush, zcs->frameEnded,
                zcs->appliedParams.fParams.checksumFlag);
        DEBUGLOG(4, "ZSTD_endStream : remaining to flush : %u", (unsigned)toFlush);
        return toFlush;
    }
}


/*-=====  Pre-defined compression levels  =====-*/
/* The compression-level tables (formerly included from clevels.h) live in
 * rust/src/zstd_compress_params.rs. */

int ZSTD_maxCLevel(void) { return ZSTD_rust_params_maxCLevel(); }
int ZSTD_minCLevel(void) { return ZSTD_rust_params_minCLevel(); }
int ZSTD_defaultCLevel(void) { return ZSTD_rust_params_defaultCLevel(); }

static ZSTD_compressionParameters ZSTD_dedicatedDictSearch_getCParams(int const compressionLevel, size_t const dictSize)
{
    ZSTD_compressionParameters const cParams =
        ZSTD_getCParams_internal(compressionLevel, 0, dictSize, ZSTD_cpm_createCDict);
    return ZSTD_rust_params_dedicatedDictSearch_getCParams(cParams);
}

/**
 * Reverses the adjustment applied to cparams when enabling dedicated dict
 * search. This is used to recover the params set to be used in the working
 * context. (Otherwise, those tables would also grow.)
 */
static void ZSTD_dedicatedDictSearch_revertCParams(
        ZSTD_compressionParameters* cParams) {
    *cParams = ZSTD_rust_params_dedicatedDictSearch_revertCParams(*cParams);
}

/*! ZSTD_getCParams_internal() :
 * @return ZSTD_compressionParameters structure for a selected compression level, srcSize and dictSize.
 *  Note: srcSizeHint 0 means 0, use ZSTD_CONTENTSIZE_UNKNOWN for unknown.
 *        Use dictSize == 0 for unknown or unused.
 *  Note: `mode` controls how we treat the `dictSize`. See docs for `ZSTD_CParamMode_e`. */
static ZSTD_compressionParameters ZSTD_getCParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode)
{
    return ZSTD_rust_params_getCParamsInternal(
            compressionLevel, srcSizeHint, dictSize, (int)mode,
            ZSTD_getCParamsExclusionMask());
}

/*! ZSTD_getCParams() :
 * @return ZSTD_compressionParameters structure for a selected compression level, srcSize and dictSize.
 *  Size values are optional, provide 0 if not known or unused */
ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize)
{
    return ZSTD_rust_params_getCParams(
            compressionLevel, srcSizeHint, dictSize,
            ZSTD_getCParamsExclusionMask());
}

/*! ZSTD_getParams() :
 *  same idea as ZSTD_getCParams()
 * @return a `ZSTD_parameters` structure (instead of `ZSTD_compressionParameters`).
 *  Fields of `ZSTD_frameParameters` are set to default values */
static ZSTD_parameters
ZSTD_getParams_internal(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize, ZSTD_CParamMode_e mode)
{
    DEBUGLOG(5, "ZSTD_getParams (cLevel=%i)", compressionLevel);
    return ZSTD_rust_params_getParamsInternal(
            compressionLevel, srcSizeHint, dictSize, (int)mode,
            ZSTD_getCParamsExclusionMask());
}

/*! ZSTD_getParams() :
 *  same idea as ZSTD_getCParams()
 * @return a `ZSTD_parameters` structure (instead of `ZSTD_compressionParameters`).
 *  Fields of `ZSTD_frameParameters` are set to default values */
ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSizeHint, size_t dictSize)
{
    return ZSTD_rust_params_getParams(
            compressionLevel, srcSizeHint, dictSize,
            ZSTD_getCParamsExclusionMask());
}

void ZSTD_registerSequenceProducer(
    ZSTD_CCtx* zc,
    void* extSeqProdState,
    ZSTD_sequenceProducer_F extSeqProdFunc)
{
    assert(zc != NULL);
    ZSTD_CCtxParams_registerSequenceProducer(
        &zc->requestedParams, extSeqProdState, extSeqProdFunc
    );
}