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feat(rust): port Huffman decompression

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Move Huffman decoding-table construction and X1/X2 single- and four-stream
decoding into Rust. The original C translation unit is now a declaration shim,
so unchanged C callers and tests resolve the public decoder ABI from the Rust
archive.

The portable implementation preserves the C workspace and error contracts,
retains the existing assembly-only internal fast loops, and mirrors the C
32-bit decode cadence so X2 writes remain within its required output window.
Forced X1/X2 modes follow the matching archive configuration from the build
integration.

Test Plan:
- cargo clippy; cargo clippy --benches; cargo clippy --tests
- cargo +nightly fmt, then repeat the Clippy checks
- cargo test --all-targets for default, forced X1, and forced X2 modes
- cargo build and cargo test for i686-unknown-linux-gnu in all three modes
- Strict normal, X1, and X2 C shim compilation
- Original fuzzer and fullbench compatibility targets

Refs: rust/README.md
Depends-on: d89ebb31
This commit is contained in:
ddidderr
2026-07-10 20:48:51 +02:00
parent d89ebb31e3
commit 27932113fd
4 changed files with 1401 additions and 1943 deletions
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lib/decompress/huf_decompress.c
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@@ -1,1944 +1,2 @@
/* ******************************************************************
* huff0 huffman decoder,
* part of Finite State Entropy library
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* You can contact the author at :
* - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
*
* 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/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memset */
#include "../common/compiler.h"
#include "../common/bitstream.h" /* BIT_* */
#include "../common/fse.h" /* to compress headers */
/* Huffman decompression is implemented in rust/src/huf_decompress.rs. */
#include "../common/huf.h"
#include "../common/error_private.h"
#include "../common/zstd_internal.h"
#include "../common/bits.h" /* ZSTD_highbit32, ZSTD_countTrailingZeros64 */
/* **************************************************************
* Constants
****************************************************************/
#define HUF_DECODER_FAST_TABLELOG 11
/* **************************************************************
* Macros
****************************************************************/
#ifdef HUF_DISABLE_FAST_DECODE
# define HUF_ENABLE_FAST_DECODE 0
#else
# define HUF_ENABLE_FAST_DECODE 1
#endif
/* These two optional macros force the use one way or another of the two
* Huffman decompression implementations. You can't force in both directions
* at the same time.
*/
#if defined(HUF_FORCE_DECOMPRESS_X1) && \
defined(HUF_FORCE_DECOMPRESS_X2)
#error "Cannot force the use of the X1 and X2 decoders at the same time!"
#endif
/* When DYNAMIC_BMI2 is enabled, fast decoders are only called when bmi2 is
* supported at runtime, so we can add the BMI2 target attribute.
* When it is disabled, we will still get BMI2 if it is enabled statically.
*/
#if DYNAMIC_BMI2
# define HUF_FAST_BMI2_ATTRS BMI2_TARGET_ATTRIBUTE
#else
# define HUF_FAST_BMI2_ATTRS
#endif
#ifdef __cplusplus
# define HUF_EXTERN_C extern "C"
#else
# define HUF_EXTERN_C
#endif
#define HUF_ASM_DECL HUF_EXTERN_C
#if DYNAMIC_BMI2
# define HUF_NEED_BMI2_FUNCTION 1
#else
# define HUF_NEED_BMI2_FUNCTION 0
#endif
/* **************************************************************
* Error Management
****************************************************************/
#define HUF_isError ERR_isError
/* **************************************************************
* Byte alignment for workSpace management
****************************************************************/
#define HUF_ALIGN(x, a) HUF_ALIGN_MASK((x), (a) - 1)
#define HUF_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
/* **************************************************************
* BMI2 Variant Wrappers
****************************************************************/
typedef size_t (*HUF_DecompressUsingDTableFn)(void *dst, size_t dstSize,
const void *cSrc,
size_t cSrcSize,
const HUF_DTable *DTable);
#if DYNAMIC_BMI2
#define HUF_DGEN(fn) \
\
static size_t fn##_default( \
void* dst, size_t dstSize, \
const void* cSrc, size_t cSrcSize, \
const HUF_DTable* DTable) \
{ \
return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable); \
} \
\
static BMI2_TARGET_ATTRIBUTE size_t fn##_bmi2( \
void* dst, size_t dstSize, \
const void* cSrc, size_t cSrcSize, \
const HUF_DTable* DTable) \
{ \
return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable); \
} \
\
static size_t fn(void* dst, size_t dstSize, void const* cSrc, \
size_t cSrcSize, HUF_DTable const* DTable, int flags) \
{ \
if (flags & HUF_flags_bmi2) { \
return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable); \
} \
return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable); \
}
#else
#define HUF_DGEN(fn) \
static size_t fn(void* dst, size_t dstSize, void const* cSrc, \
size_t cSrcSize, HUF_DTable const* DTable, int flags) \
{ \
(void)flags; \
return fn##_body(dst, dstSize, cSrc, cSrcSize, DTable); \
}
#endif
/*-***************************/
/* generic DTableDesc */
/*-***************************/
typedef struct { BYTE maxTableLog; BYTE tableType; BYTE tableLog; BYTE reserved; } DTableDesc;
static DTableDesc HUF_getDTableDesc(const HUF_DTable* table)
{
DTableDesc dtd;
ZSTD_memcpy(&dtd, table, sizeof(dtd));
return dtd;
}
static size_t HUF_initFastDStream(BYTE const* ip) {
BYTE const lastByte = ip[7];
size_t const bitsConsumed = lastByte ? 8 - ZSTD_highbit32(lastByte) : 0;
size_t const value = MEM_readLEST(ip) | 1;
assert(bitsConsumed <= 8);
assert(sizeof(size_t) == 8);
return value << bitsConsumed;
}
/**
* The input/output arguments to the Huffman fast decoding loop:
*
* ip [in/out] - The input pointers, must be updated to reflect what is consumed.
* op [in/out] - The output pointers, must be updated to reflect what is written.
* bits [in/out] - The bitstream containers, must be updated to reflect the current state.
* dt [in] - The decoding table.
* ilowest [in] - The beginning of the valid range of the input. Decoders may read
* down to this pointer. It may be below iend[0].
* oend [in] - The end of the output stream. op[3] must not cross oend.
* iend [in] - The end of each input stream. ip[i] may cross iend[i],
* as long as it is above ilowest, but that indicates corruption.
*/
typedef struct {
BYTE const* ip[4];
BYTE* op[4];
U64 bits[4];
void const* dt;
BYTE const* ilowest;
BYTE* oend;
BYTE const* iend[4];
} HUF_DecompressFastArgs;
typedef void (*HUF_DecompressFastLoopFn)(HUF_DecompressFastArgs*);
/**
* Initializes args for the fast decoding loop.
* @returns 1 on success
* 0 if the fallback implementation should be used.
* Or an error code on failure.
*/
static size_t HUF_DecompressFastArgs_init(HUF_DecompressFastArgs* args, void* dst, size_t dstSize, void const* src, size_t srcSize, const HUF_DTable* DTable)
{
void const* dt = DTable + 1;
U32 const dtLog = HUF_getDTableDesc(DTable).tableLog;
const BYTE* const istart = (const BYTE*)src;
BYTE* const oend = ZSTD_maybeNullPtrAdd((BYTE*)dst, dstSize);
/* The fast decoding loop assumes 64-bit little-endian.
* This condition is false on x32.
*/
if (!MEM_isLittleEndian() || MEM_32bits())
return 0;
/* Avoid nullptr addition */
if (dstSize == 0)
return 0;
assert(dst != NULL);
/* strict minimum : jump table + 1 byte per stream */
if (srcSize < 10)
return ERROR(corruption_detected);
/* Must have at least 8 bytes per stream because we don't handle initializing smaller bit containers.
* If table log is not correct at this point, fallback to the old decoder.
* On small inputs we don't have enough data to trigger the fast loop, so use the old decoder.
*/
if (dtLog != HUF_DECODER_FAST_TABLELOG)
return 0;
/* Read the jump table. */
{
size_t const length1 = MEM_readLE16(istart);
size_t const length2 = MEM_readLE16(istart+2);
size_t const length3 = MEM_readLE16(istart+4);
size_t const length4 = srcSize - (length1 + length2 + length3 + 6);
args->iend[0] = istart + 6; /* jumpTable */
args->iend[1] = args->iend[0] + length1;
args->iend[2] = args->iend[1] + length2;
args->iend[3] = args->iend[2] + length3;
/* HUF_initFastDStream() requires this, and this small of an input
* won't benefit from the ASM loop anyways.
*/
if (length1 < 8 || length2 < 8 || length3 < 8 || length4 < 8)
return 0;
if (length4 > srcSize) return ERROR(corruption_detected); /* overflow */
}
/* ip[] contains the position that is currently loaded into bits[]. */
args->ip[0] = args->iend[1] - sizeof(U64);
args->ip[1] = args->iend[2] - sizeof(U64);
args->ip[2] = args->iend[3] - sizeof(U64);
args->ip[3] = (BYTE const*)src + srcSize - sizeof(U64);
/* op[] contains the output pointers. */
args->op[0] = (BYTE*)dst;
args->op[1] = args->op[0] + (dstSize+3)/4;
args->op[2] = args->op[1] + (dstSize+3)/4;
args->op[3] = args->op[2] + (dstSize+3)/4;
/* No point to call the ASM loop for tiny outputs. */
if (args->op[3] >= oend)
return 0;
/* bits[] is the bit container.
* It is read from the MSB down to the LSB.
* It is shifted left as it is read, and zeros are
* shifted in. After the lowest valid bit a 1 is
* set, so that CountTrailingZeros(bits[]) can be used
* to count how many bits we've consumed.
*/
args->bits[0] = HUF_initFastDStream(args->ip[0]);
args->bits[1] = HUF_initFastDStream(args->ip[1]);
args->bits[2] = HUF_initFastDStream(args->ip[2]);
args->bits[3] = HUF_initFastDStream(args->ip[3]);
/* The decoders must be sure to never read beyond ilowest.
* This is lower than iend[0], but allowing decoders to read
* down to ilowest can allow an extra iteration or two in the
* fast loop.
*/
args->ilowest = istart;
args->oend = oend;
args->dt = dt;
return 1;
}
static size_t HUF_initRemainingDStream(BIT_DStream_t* bit, HUF_DecompressFastArgs const* args, int stream, BYTE* segmentEnd)
{
/* Validate that we haven't overwritten. */
if (args->op[stream] > segmentEnd)
return ERROR(corruption_detected);
/* Validate that we haven't read beyond iend[].
* Note that ip[] may be < iend[] because the MSB is
* the next bit to read, and we may have consumed 100%
* of the stream, so down to iend[i] - 8 is valid.
*/
if (args->ip[stream] < args->iend[stream] - 8)
return ERROR(corruption_detected);
/* Construct the BIT_DStream_t. */
assert(sizeof(size_t) == 8);
bit->bitContainer = MEM_readLEST(args->ip[stream]);
bit->bitsConsumed = ZSTD_countTrailingZeros64(args->bits[stream]);
bit->start = (const char*)args->ilowest;
bit->limitPtr = bit->start + sizeof(size_t);
bit->ptr = (const char*)args->ip[stream];
return 0;
}
/* Calls X(N) for each stream 0, 1, 2, 3. */
#define HUF_4X_FOR_EACH_STREAM(X) \
do { \
X(0); \
X(1); \
X(2); \
X(3); \
} while (0)
/* Calls X(N, var) for each stream 0, 1, 2, 3. */
#define HUF_4X_FOR_EACH_STREAM_WITH_VAR(X, var) \
do { \
X(0, (var)); \
X(1, (var)); \
X(2, (var)); \
X(3, (var)); \
} while (0)
#ifndef HUF_FORCE_DECOMPRESS_X2
/*-***************************/
/* single-symbol decoding */
/*-***************************/
typedef struct { BYTE nbBits; BYTE byte; } HUF_DEltX1; /* single-symbol decoding */
/**
* Packs 4 HUF_DEltX1 structs into a U64. This is used to lay down 4 entries at
* a time.
*/
static U64 HUF_DEltX1_set4(BYTE symbol, BYTE nbBits) {
U64 D4;
if (MEM_isLittleEndian()) {
D4 = (U64)((symbol << 8) + nbBits);
} else {
D4 = (U64)(symbol + (nbBits << 8));
}
assert(D4 < (1U << 16));
D4 *= 0x0001000100010001ULL;
return D4;
}
/**
* Increase the tableLog to targetTableLog and rescales the stats.
* If tableLog > targetTableLog this is a no-op.
* @returns New tableLog
*/
static U32 HUF_rescaleStats(BYTE* huffWeight, U32* rankVal, U32 nbSymbols, U32 tableLog, U32 targetTableLog)
{
if (tableLog > targetTableLog)
return tableLog;
if (tableLog < targetTableLog) {
U32 const scale = targetTableLog - tableLog;
U32 s;
/* Increase the weight for all non-zero probability symbols by scale. */
for (s = 0; s < nbSymbols; ++s) {
huffWeight[s] += (BYTE)((huffWeight[s] == 0) ? 0 : scale);
}
/* Update rankVal to reflect the new weights.
* All weights except 0 get moved to weight + scale.
* Weights [1, scale] are empty.
*/
for (s = targetTableLog; s > scale; --s) {
rankVal[s] = rankVal[s - scale];
}
for (s = scale; s > 0; --s) {
rankVal[s] = 0;
}
}
return targetTableLog;
}
typedef struct {
U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1];
U32 rankStart[HUF_TABLELOG_ABSOLUTEMAX + 1];
U32 statsWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
BYTE symbols[HUF_SYMBOLVALUE_MAX + 1];
BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1];
} HUF_ReadDTableX1_Workspace;
size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int flags)
{
U32 tableLog = 0;
U32 nbSymbols = 0;
size_t iSize;
void* const dtPtr = DTable + 1;
HUF_DEltX1* const dt = (HUF_DEltX1*)dtPtr;
HUF_ReadDTableX1_Workspace* wksp = (HUF_ReadDTableX1_Workspace*)workSpace;
DEBUG_STATIC_ASSERT(HUF_DECOMPRESS_WORKSPACE_SIZE >= sizeof(*wksp));
if (sizeof(*wksp) > wkspSize) return ERROR(tableLog_tooLarge);
DEBUG_STATIC_ASSERT(sizeof(DTableDesc) == sizeof(HUF_DTable));
/* ZSTD_memset(huffWeight, 0, sizeof(huffWeight)); */ /* is not necessary, even though some analyzer complain ... */
iSize = HUF_readStats_wksp(wksp->huffWeight, HUF_SYMBOLVALUE_MAX + 1, wksp->rankVal, &nbSymbols, &tableLog, src, srcSize, wksp->statsWksp, sizeof(wksp->statsWksp), flags);
if (HUF_isError(iSize)) return iSize;
/* Table header */
{ DTableDesc dtd = HUF_getDTableDesc(DTable);
U32 const maxTableLog = dtd.maxTableLog + 1;
U32 const targetTableLog = MIN(maxTableLog, HUF_DECODER_FAST_TABLELOG);
tableLog = HUF_rescaleStats(wksp->huffWeight, wksp->rankVal, nbSymbols, tableLog, targetTableLog);
if (tableLog > (U32)(dtd.maxTableLog+1)) return ERROR(tableLog_tooLarge); /* DTable too small, Huffman tree cannot fit in */
dtd.tableType = 0;
dtd.tableLog = (BYTE)tableLog;
ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
}
/* Compute symbols and rankStart given rankVal:
*
* rankVal already contains the number of values of each weight.
*
* symbols contains the symbols ordered by weight. First are the rankVal[0]
* weight 0 symbols, followed by the rankVal[1] weight 1 symbols, and so on.
* symbols[0] is filled (but unused) to avoid a branch.
*
* rankStart contains the offset where each rank belongs in the DTable.
* rankStart[0] is not filled because there are no entries in the table for
* weight 0.
*/
{ int n;
U32 nextRankStart = 0;
int const unroll = 4;
int const nLimit = (int)nbSymbols - unroll + 1;
for (n=0; n<(int)tableLog+1; n++) {
U32 const curr = nextRankStart;
nextRankStart += wksp->rankVal[n];
wksp->rankStart[n] = curr;
}
for (n=0; n < nLimit; n += unroll) {
int u;
for (u=0; u < unroll; ++u) {
size_t const w = wksp->huffWeight[n+u];
wksp->symbols[wksp->rankStart[w]++] = (BYTE)(n+u);
}
}
for (; n < (int)nbSymbols; ++n) {
size_t const w = wksp->huffWeight[n];
wksp->symbols[wksp->rankStart[w]++] = (BYTE)n;
}
}
/* fill DTable
* We fill all entries of each weight in order.
* That way length is a constant for each iteration of the outer loop.
* We can switch based on the length to a different inner loop which is
* optimized for that particular case.
*/
{ U32 w;
int symbol = wksp->rankVal[0];
int rankStart = 0;
for (w=1; w<tableLog+1; ++w) {
int const symbolCount = wksp->rankVal[w];
int const length = (1 << w) >> 1;
int uStart = rankStart;
BYTE const nbBits = (BYTE)(tableLog + 1 - w);
int s;
int u;
switch (length) {
case 1:
for (s=0; s<symbolCount; ++s) {
HUF_DEltX1 D;
D.byte = wksp->symbols[symbol + s];
D.nbBits = nbBits;
dt[uStart] = D;
uStart += 1;
}
break;
case 2:
for (s=0; s<symbolCount; ++s) {
HUF_DEltX1 D;
D.byte = wksp->symbols[symbol + s];
D.nbBits = nbBits;
dt[uStart+0] = D;
dt[uStart+1] = D;
uStart += 2;
}
break;
case 4:
for (s=0; s<symbolCount; ++s) {
U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
MEM_write64(dt + uStart, D4);
uStart += 4;
}
break;
case 8:
for (s=0; s<symbolCount; ++s) {
U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
MEM_write64(dt + uStart, D4);
MEM_write64(dt + uStart + 4, D4);
uStart += 8;
}
break;
default:
for (s=0; s<symbolCount; ++s) {
U64 const D4 = HUF_DEltX1_set4(wksp->symbols[symbol + s], nbBits);
for (u=0; u < length; u += 16) {
MEM_write64(dt + uStart + u + 0, D4);
MEM_write64(dt + uStart + u + 4, D4);
MEM_write64(dt + uStart + u + 8, D4);
MEM_write64(dt + uStart + u + 12, D4);
}
assert(u == length);
uStart += length;
}
break;
}
symbol += symbolCount;
rankStart += symbolCount * length;
}
}
return iSize;
}
FORCE_INLINE_TEMPLATE BYTE
HUF_decodeSymbolX1(BIT_DStream_t* Dstream, const HUF_DEltX1* dt, const U32 dtLog)
{
size_t const val = BIT_lookBitsFast(Dstream, dtLog); /* note : dtLog >= 1 */
BYTE const c = dt[val].byte;
BIT_skipBits(Dstream, dt[val].nbBits);
return c;
}
#define HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr) \
do { *ptr++ = HUF_decodeSymbolX1(DStreamPtr, dt, dtLog); } while (0)
#define HUF_DECODE_SYMBOLX1_1(ptr, DStreamPtr) \
do { \
if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr); \
} while (0)
#define HUF_DECODE_SYMBOLX1_2(ptr, DStreamPtr) \
do { \
if (MEM_64bits()) \
HUF_DECODE_SYMBOLX1_0(ptr, DStreamPtr); \
} while (0)
HINT_INLINE size_t
HUF_decodeStreamX1(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, const HUF_DEltX1* const dt, const U32 dtLog)
{
BYTE* const pStart = p;
/* up to 4 symbols at a time */
if ((pEnd - p) > 3) {
while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-3)) {
HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
HUF_DECODE_SYMBOLX1_1(p, bitDPtr);
HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
}
} else {
BIT_reloadDStream(bitDPtr);
}
/* [0-3] symbols remaining */
if (MEM_32bits())
while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd))
HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
/* no more data to retrieve from bitstream, no need to reload */
while (p < pEnd)
HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
return (size_t)(pEnd-pStart);
}
FORCE_INLINE_TEMPLATE size_t
HUF_decompress1X1_usingDTable_internal_body(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable)
{
BYTE* op = (BYTE*)dst;
BYTE* const oend = ZSTD_maybeNullPtrAdd(op, dstSize);
const void* dtPtr = DTable + 1;
const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
BIT_DStream_t bitD;
DTableDesc const dtd = HUF_getDTableDesc(DTable);
U32 const dtLog = dtd.tableLog;
CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
HUF_decodeStreamX1(op, &bitD, oend, dt, dtLog);
if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
return dstSize;
}
/* HUF_decompress4X1_usingDTable_internal_body():
* Conditions :
* @dstSize >= 6
*/
FORCE_INLINE_TEMPLATE size_t
HUF_decompress4X1_usingDTable_internal_body(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable)
{
/* Check */
if (cSrcSize < 10) return ERROR(corruption_detected); /* strict minimum : jump table + 1 byte per stream */
if (dstSize < 6) return ERROR(corruption_detected); /* stream 4-split doesn't work */
{ const BYTE* const istart = (const BYTE*) cSrc;
BYTE* const ostart = (BYTE*) dst;
BYTE* const oend = ostart + dstSize;
BYTE* const olimit = oend - 3;
const void* const dtPtr = DTable + 1;
const HUF_DEltX1* const dt = (const HUF_DEltX1*)dtPtr;
/* Init */
BIT_DStream_t bitD1;
BIT_DStream_t bitD2;
BIT_DStream_t bitD3;
BIT_DStream_t bitD4;
size_t const length1 = MEM_readLE16(istart);
size_t const length2 = MEM_readLE16(istart+2);
size_t const length3 = MEM_readLE16(istart+4);
size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
const BYTE* const istart1 = istart + 6; /* jumpTable */
const BYTE* const istart2 = istart1 + length1;
const BYTE* const istart3 = istart2 + length2;
const BYTE* const istart4 = istart3 + length3;
const size_t segmentSize = (dstSize+3) / 4;
BYTE* const opStart2 = ostart + segmentSize;
BYTE* const opStart3 = opStart2 + segmentSize;
BYTE* const opStart4 = opStart3 + segmentSize;
BYTE* op1 = ostart;
BYTE* op2 = opStart2;
BYTE* op3 = opStart3;
BYTE* op4 = opStart4;
DTableDesc const dtd = HUF_getDTableDesc(DTable);
U32 const dtLog = dtd.tableLog;
U32 endSignal = 1;
if (length4 > cSrcSize) return ERROR(corruption_detected); /* overflow */
if (opStart4 > oend) return ERROR(corruption_detected); /* overflow */
assert(dstSize >= 6); /* validated above */
CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
/* up to 16 symbols per loop (4 symbols per stream) in 64-bit mode */
if ((size_t)(oend - op4) >= sizeof(size_t)) {
for ( ; (endSignal) & (op4 < olimit) ; ) {
HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
HUF_DECODE_SYMBOLX1_1(op1, &bitD1);
HUF_DECODE_SYMBOLX1_1(op2, &bitD2);
HUF_DECODE_SYMBOLX1_1(op3, &bitD3);
HUF_DECODE_SYMBOLX1_1(op4, &bitD4);
HUF_DECODE_SYMBOLX1_2(op1, &bitD1);
HUF_DECODE_SYMBOLX1_2(op2, &bitD2);
HUF_DECODE_SYMBOLX1_2(op3, &bitD3);
HUF_DECODE_SYMBOLX1_2(op4, &bitD4);
HUF_DECODE_SYMBOLX1_0(op1, &bitD1);
HUF_DECODE_SYMBOLX1_0(op2, &bitD2);
HUF_DECODE_SYMBOLX1_0(op3, &bitD3);
HUF_DECODE_SYMBOLX1_0(op4, &bitD4);
endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
}
}
/* check corruption */
/* note : should not be necessary : op# advance in lock step, and we control op4.
* but curiously, binary generated by gcc 7.2 & 7.3 with -mbmi2 runs faster when >=1 test is present */
if (op1 > opStart2) return ERROR(corruption_detected);
if (op2 > opStart3) return ERROR(corruption_detected);
if (op3 > opStart4) return ERROR(corruption_detected);
/* note : op4 supposed already verified within main loop */
/* finish bitStreams one by one */
HUF_decodeStreamX1(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX1(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX1(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX1(op4, &bitD4, oend, dt, dtLog);
/* check */
{ U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endCheck) return ERROR(corruption_detected); }
/* decoded size */
return dstSize;
}
}
#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X1_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif
static
size_t HUF_decompress4X1_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#if ZSTD_ENABLE_ASM_X86_64_BMI2
HUF_ASM_DECL void HUF_decompress4X1_usingDTable_internal_fast_asm_loop(HUF_DecompressFastArgs* args) ZSTDLIB_HIDDEN;
#endif
static HUF_FAST_BMI2_ATTRS
void HUF_decompress4X1_usingDTable_internal_fast_c_loop(HUF_DecompressFastArgs* args)
{
U64 bits[4];
BYTE const* ip[4];
BYTE* op[4];
U16 const* const dtable = (U16 const*)args->dt;
BYTE* const oend = args->oend;
BYTE const* const ilowest = args->ilowest;
/* Copy the arguments to local variables */
ZSTD_memcpy(&bits, &args->bits, sizeof(bits));
ZSTD_memcpy((void*)(&ip), &args->ip, sizeof(ip));
ZSTD_memcpy(&op, &args->op, sizeof(op));
assert(MEM_isLittleEndian());
assert(!MEM_32bits());
for (;;) {
BYTE* olimit;
int stream;
/* Assert loop preconditions */
#ifndef NDEBUG
for (stream = 0; stream < 4; ++stream) {
assert(op[stream] <= (stream == 3 ? oend : op[stream + 1]));
assert(ip[stream] >= ilowest);
}
#endif
/* Compute olimit */
{
/* Each iteration produces 5 output symbols per stream */
size_t const oiters = (size_t)(oend - op[3]) / 5;
/* Each iteration consumes up to 11 bits * 5 = 55 bits < 7 bytes
* per stream.
*/
size_t const iiters = (size_t)(ip[0] - ilowest) / 7;
/* We can safely run iters iterations before running bounds checks */
size_t const iters = MIN(oiters, iiters);
size_t const symbols = iters * 5;
/* We can simply check that op[3] < olimit, instead of checking all
* of our bounds, since we can't hit the other bounds until we've run
* iters iterations, which only happens when op[3] == olimit.
*/
olimit = op[3] + symbols;
/* Exit fast decoding loop once we reach the end. */
if (op[3] == olimit)
break;
/* Exit the decoding loop if any input pointer has crossed the
* previous one. This indicates corruption, and a precondition
* to our loop is that ip[i] >= ip[0].
*/
for (stream = 1; stream < 4; ++stream) {
if (ip[stream] < ip[stream - 1])
goto _out;
}
}
#ifndef NDEBUG
for (stream = 1; stream < 4; ++stream) {
assert(ip[stream] >= ip[stream - 1]);
}
#endif
#define HUF_4X1_DECODE_SYMBOL(_stream, _symbol) \
do { \
int const index = (int)(bits[(_stream)] >> 53); \
int const entry = (int)dtable[index]; \
bits[(_stream)] <<= (entry & 0x3F); \
op[(_stream)][(_symbol)] = (BYTE)((entry >> 8) & 0xFF); \
} while (0)
#define HUF_4X1_RELOAD_STREAM(_stream) \
do { \
int const ctz = ZSTD_countTrailingZeros64(bits[(_stream)]); \
int const nbBits = ctz & 7; \
int const nbBytes = ctz >> 3; \
op[(_stream)] += 5; \
ip[(_stream)] -= nbBytes; \
bits[(_stream)] = MEM_read64(ip[(_stream)]) | 1; \
bits[(_stream)] <<= nbBits; \
} while (0)
/* Manually unroll the loop because compilers don't consistently
* unroll the inner loops, which destroys performance.
*/
do {
/* Decode 5 symbols in each of the 4 streams */
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X1_DECODE_SYMBOL, 0);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X1_DECODE_SYMBOL, 1);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X1_DECODE_SYMBOL, 2);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X1_DECODE_SYMBOL, 3);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X1_DECODE_SYMBOL, 4);
/* Reload each of the 4 the bitstreams */
HUF_4X_FOR_EACH_STREAM(HUF_4X1_RELOAD_STREAM);
} while (op[3] < olimit);
#undef HUF_4X1_DECODE_SYMBOL
#undef HUF_4X1_RELOAD_STREAM
}
_out:
/* Save the final values of each of the state variables back to args. */
ZSTD_memcpy(&args->bits, &bits, sizeof(bits));
ZSTD_memcpy((void*)(&args->ip), &ip, sizeof(ip));
ZSTD_memcpy(&args->op, &op, sizeof(op));
}
/**
* @returns @p dstSize on success (>= 6)
* 0 if the fallback implementation should be used
* An error if an error occurred
*/
static HUF_FAST_BMI2_ATTRS
size_t
HUF_decompress4X1_usingDTable_internal_fast(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable,
HUF_DecompressFastLoopFn loopFn)
{
void const* dt = DTable + 1;
BYTE const* const ilowest = (BYTE const*)cSrc;
BYTE* const oend = ZSTD_maybeNullPtrAdd((BYTE*)dst, dstSize);
HUF_DecompressFastArgs args;
{ size_t const ret = HUF_DecompressFastArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
FORWARD_IF_ERROR(ret, "Failed to init fast loop args");
if (ret == 0)
return 0;
}
assert(args.ip[0] >= args.ilowest);
loopFn(&args);
/* Our loop guarantees that ip[] >= ilowest and that we haven't
* overwritten any op[].
*/
assert(args.ip[0] >= ilowest);
assert(args.ip[0] >= ilowest);
assert(args.ip[1] >= ilowest);
assert(args.ip[2] >= ilowest);
assert(args.ip[3] >= ilowest);
assert(args.op[3] <= oend);
assert(ilowest == args.ilowest);
assert(ilowest + 6 == args.iend[0]);
(void)ilowest;
/* finish bit streams one by one. */
{ size_t const segmentSize = (dstSize+3) / 4;
BYTE* segmentEnd = (BYTE*)dst;
int i;
for (i = 0; i < 4; ++i) {
BIT_DStream_t bit;
if (segmentSize <= (size_t)(oend - segmentEnd))
segmentEnd += segmentSize;
else
segmentEnd = oend;
FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
/* Decompress and validate that we've produced exactly the expected length. */
args.op[i] += HUF_decodeStreamX1(args.op[i], &bit, segmentEnd, (HUF_DEltX1 const*)dt, HUF_DECODER_FAST_TABLELOG);
if (args.op[i] != segmentEnd) return ERROR(corruption_detected);
}
}
/* decoded size */
assert(dstSize != 0);
return dstSize;
}
HUF_DGEN(HUF_decompress1X1_usingDTable_internal)
static size_t HUF_decompress4X1_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X1_usingDTable_internal_default;
HUF_DecompressFastLoopFn loopFn = HUF_decompress4X1_usingDTable_internal_fast_c_loop;
#if DYNAMIC_BMI2
if (flags & HUF_flags_bmi2) {
fallbackFn = HUF_decompress4X1_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X1_usingDTable_internal_fast_asm_loop;
}
# endif
} else {
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif
#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X1_usingDTable_internal_fast_asm_loop;
}
#endif
if (HUF_ENABLE_FAST_DECODE && !(flags & HUF_flags_disableFast)) {
size_t const ret = HUF_decompress4X1_usingDTable_internal_fast(dst, dstSize, cSrc, cSrcSize, DTable, loopFn);
if (ret != 0)
return ret;
}
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
static size_t HUF_decompress4X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
void* workSpace, size_t wkspSize, int flags)
{
const BYTE* ip = (const BYTE*) cSrc;
size_t const hSize = HUF_readDTableX1_wksp(dctx, cSrc, cSrcSize, workSpace, wkspSize, flags);
if (HUF_isError(hSize)) return hSize;
if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
ip += hSize; cSrcSize -= hSize;
return HUF_decompress4X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, flags);
}
#endif /* HUF_FORCE_DECOMPRESS_X2 */
#ifndef HUF_FORCE_DECOMPRESS_X1
/* *************************/
/* double-symbols decoding */
/* *************************/
typedef struct { U16 sequence; BYTE nbBits; BYTE length; } HUF_DEltX2; /* double-symbols decoding */
typedef struct { BYTE symbol; } sortedSymbol_t;
typedef U32 rankValCol_t[HUF_TABLELOG_MAX + 1];
typedef rankValCol_t rankVal_t[HUF_TABLELOG_MAX];
/**
* Constructs a HUF_DEltX2 in a U32.
*/
static U32 HUF_buildDEltX2U32(U32 symbol, U32 nbBits, U32 baseSeq, int level)
{
U32 seq;
DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, sequence) == 0);
DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, nbBits) == 2);
DEBUG_STATIC_ASSERT(offsetof(HUF_DEltX2, length) == 3);
DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(U32));
if (MEM_isLittleEndian()) {
seq = level == 1 ? symbol : (baseSeq + (symbol << 8));
return seq + (nbBits << 16) + ((U32)level << 24);
} else {
seq = level == 1 ? (symbol << 8) : ((baseSeq << 8) + symbol);
return (seq << 16) + (nbBits << 8) + (U32)level;
}
}
/**
* Constructs a HUF_DEltX2.
*/
static HUF_DEltX2 HUF_buildDEltX2(U32 symbol, U32 nbBits, U32 baseSeq, int level)
{
HUF_DEltX2 DElt;
U32 const val = HUF_buildDEltX2U32(symbol, nbBits, baseSeq, level);
DEBUG_STATIC_ASSERT(sizeof(DElt) == sizeof(val));
ZSTD_memcpy(&DElt, &val, sizeof(val));
return DElt;
}
/**
* Constructs 2 HUF_DEltX2s and packs them into a U64.
*/
static U64 HUF_buildDEltX2U64(U32 symbol, U32 nbBits, U16 baseSeq, int level)
{
U32 DElt = HUF_buildDEltX2U32(symbol, nbBits, baseSeq, level);
return (U64)DElt + ((U64)DElt << 32);
}
/**
* Fills the DTable rank with all the symbols from [begin, end) that are each
* nbBits long.
*
* @param DTableRank The start of the rank in the DTable.
* @param begin The first symbol to fill (inclusive).
* @param end The last symbol to fill (exclusive).
* @param nbBits Each symbol is nbBits long.
* @param tableLog The table log.
* @param baseSeq If level == 1 { 0 } else { the first level symbol }
* @param level The level in the table. Must be 1 or 2.
*/
static void HUF_fillDTableX2ForWeight(
HUF_DEltX2* DTableRank,
sortedSymbol_t const* begin, sortedSymbol_t const* end,
U32 nbBits, U32 tableLog,
U16 baseSeq, int const level)
{
U32 const length = 1U << ((tableLog - nbBits) & 0x1F /* quiet static-analyzer */);
const sortedSymbol_t* ptr;
assert(level >= 1 && level <= 2);
switch (length) {
case 1:
for (ptr = begin; ptr != end; ++ptr) {
HUF_DEltX2 const DElt = HUF_buildDEltX2(ptr->symbol, nbBits, baseSeq, level);
*DTableRank++ = DElt;
}
break;
case 2:
for (ptr = begin; ptr != end; ++ptr) {
HUF_DEltX2 const DElt = HUF_buildDEltX2(ptr->symbol, nbBits, baseSeq, level);
DTableRank[0] = DElt;
DTableRank[1] = DElt;
DTableRank += 2;
}
break;
case 4:
for (ptr = begin; ptr != end; ++ptr) {
U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
DTableRank += 4;
}
break;
case 8:
for (ptr = begin; ptr != end; ++ptr) {
U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 4, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 6, &DEltX2, sizeof(DEltX2));
DTableRank += 8;
}
break;
default:
for (ptr = begin; ptr != end; ++ptr) {
U64 const DEltX2 = HUF_buildDEltX2U64(ptr->symbol, nbBits, baseSeq, level);
HUF_DEltX2* const DTableRankEnd = DTableRank + length;
for (; DTableRank != DTableRankEnd; DTableRank += 8) {
ZSTD_memcpy(DTableRank + 0, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 2, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 4, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTableRank + 6, &DEltX2, sizeof(DEltX2));
}
}
break;
}
}
/* HUF_fillDTableX2Level2() :
* `rankValOrigin` must be a table of at least (HUF_TABLELOG_MAX + 1) U32 */
static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 targetLog, const U32 consumedBits,
const U32* rankVal, const int minWeight, const int maxWeight1,
const sortedSymbol_t* sortedSymbols, U32 const* rankStart,
U32 nbBitsBaseline, U16 baseSeq)
{
/* Fill skipped values (all positions up to rankVal[minWeight]).
* These are positions only get a single symbol because the combined weight
* is too large.
*/
if (minWeight>1) {
U32 const length = 1U << ((targetLog - consumedBits) & 0x1F /* quiet static-analyzer */);
U64 const DEltX2 = HUF_buildDEltX2U64(baseSeq, consumedBits, /* baseSeq */ 0, /* level */ 1);
int const skipSize = rankVal[minWeight];
assert(length > 1);
assert((U32)skipSize < length);
switch (length) {
case 2:
assert(skipSize == 1);
ZSTD_memcpy(DTable, &DEltX2, sizeof(DEltX2));
break;
case 4:
assert(skipSize <= 4);
ZSTD_memcpy(DTable + 0, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTable + 2, &DEltX2, sizeof(DEltX2));
break;
default:
{
int i;
for (i = 0; i < skipSize; i += 8) {
ZSTD_memcpy(DTable + i + 0, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTable + i + 2, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTable + i + 4, &DEltX2, sizeof(DEltX2));
ZSTD_memcpy(DTable + i + 6, &DEltX2, sizeof(DEltX2));
}
}
}
}
/* Fill each of the second level symbols by weight. */
{
int w;
for (w = minWeight; w < maxWeight1; ++w) {
int const begin = rankStart[w];
int const end = rankStart[w+1];
U32 const nbBits = nbBitsBaseline - w;
U32 const totalBits = nbBits + consumedBits;
HUF_fillDTableX2ForWeight(
DTable + rankVal[w],
sortedSymbols + begin, sortedSymbols + end,
totalBits, targetLog,
baseSeq, /* level */ 2);
}
}
}
static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
const sortedSymbol_t* sortedList,
const U32* rankStart, rankValCol_t* rankValOrigin, const U32 maxWeight,
const U32 nbBitsBaseline)
{
U32* const rankVal = rankValOrigin[0];
const int scaleLog = nbBitsBaseline - targetLog; /* note : targetLog >= srcLog, hence scaleLog <= 1 */
const U32 minBits = nbBitsBaseline - maxWeight;
int w;
int const wEnd = (int)maxWeight + 1;
/* Fill DTable in order of weight. */
for (w = 1; w < wEnd; ++w) {
int const begin = (int)rankStart[w];
int const end = (int)rankStart[w+1];
U32 const nbBits = nbBitsBaseline - w;
if (targetLog-nbBits >= minBits) {
/* Enough room for a second symbol. */
int start = rankVal[w];
U32 const length = 1U << ((targetLog - nbBits) & 0x1F /* quiet static-analyzer */);
int minWeight = nbBits + scaleLog;
int s;
if (minWeight < 1) minWeight = 1;
/* Fill the DTable for every symbol of weight w.
* These symbols get at least 1 second symbol.
*/
for (s = begin; s != end; ++s) {
HUF_fillDTableX2Level2(
DTable + start, targetLog, nbBits,
rankValOrigin[nbBits], minWeight, wEnd,
sortedList, rankStart,
nbBitsBaseline, sortedList[s].symbol);
start += length;
}
} else {
/* Only a single symbol. */
HUF_fillDTableX2ForWeight(
DTable + rankVal[w],
sortedList + begin, sortedList + end,
nbBits, targetLog,
/* baseSeq */ 0, /* level */ 1);
}
}
}
typedef struct {
rankValCol_t rankVal[HUF_TABLELOG_MAX];
U32 rankStats[HUF_TABLELOG_MAX + 1];
U32 rankStart0[HUF_TABLELOG_MAX + 3];
sortedSymbol_t sortedSymbol[HUF_SYMBOLVALUE_MAX + 1];
BYTE weightList[HUF_SYMBOLVALUE_MAX + 1];
U32 calleeWksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
} HUF_ReadDTableX2_Workspace;
size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
const void* src, size_t srcSize,
void* workSpace, size_t wkspSize, int flags)
{
U32 tableLog, maxW, nbSymbols;
DTableDesc dtd = HUF_getDTableDesc(DTable);
U32 maxTableLog = dtd.maxTableLog;
size_t iSize;
void* dtPtr = DTable+1; /* force compiler to avoid strict-aliasing */
HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
U32 *rankStart;
HUF_ReadDTableX2_Workspace* const wksp = (HUF_ReadDTableX2_Workspace*)workSpace;
if (sizeof(*wksp) > wkspSize) return ERROR(GENERIC);
rankStart = wksp->rankStart0 + 1;
ZSTD_memset(wksp->rankStats, 0, sizeof(wksp->rankStats));
ZSTD_memset(wksp->rankStart0, 0, sizeof(wksp->rankStart0));
DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable)); /* if compiler fails here, assertion is wrong */
if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
/* ZSTD_memset(weightList, 0, sizeof(weightList)); */ /* is not necessary, even though some analyzer complain ... */
iSize = HUF_readStats_wksp(wksp->weightList, HUF_SYMBOLVALUE_MAX + 1, wksp->rankStats, &nbSymbols, &tableLog, src, srcSize, wksp->calleeWksp, sizeof(wksp->calleeWksp), flags);
if (HUF_isError(iSize)) return iSize;
/* check result */
if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge); /* DTable can't fit code depth */
if (tableLog <= HUF_DECODER_FAST_TABLELOG && maxTableLog > HUF_DECODER_FAST_TABLELOG) maxTableLog = HUF_DECODER_FAST_TABLELOG;
/* find maxWeight */
for (maxW = tableLog; wksp->rankStats[maxW]==0; maxW--) {} /* necessarily finds a solution before 0 */
/* Get start index of each weight */
{ U32 w, nextRankStart = 0;
for (w=1; w<maxW+1; w++) {
U32 curr = nextRankStart;
nextRankStart += wksp->rankStats[w];
rankStart[w] = curr;
}
rankStart[0] = nextRankStart; /* put all 0w symbols at the end of sorted list*/
rankStart[maxW+1] = nextRankStart;
}
/* sort symbols by weight */
{ U32 s;
for (s=0; s<nbSymbols; s++) {
U32 const w = wksp->weightList[s];
U32 const r = rankStart[w]++;
wksp->sortedSymbol[r].symbol = (BYTE)s;
}
rankStart[0] = 0; /* forget 0w symbols; this is beginning of weight(1) */
}
/* Build rankVal */
{ U32* const rankVal0 = wksp->rankVal[0];
{ int const rescale = (maxTableLog-tableLog) - 1; /* tableLog <= maxTableLog */
U32 nextRankVal = 0;
U32 w;
for (w=1; w<maxW+1; w++) {
U32 curr = nextRankVal;
nextRankVal += wksp->rankStats[w] << (w+rescale);
rankVal0[w] = curr;
} }
{ U32 const minBits = tableLog+1 - maxW;
U32 consumed;
for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
U32* const rankValPtr = wksp->rankVal[consumed];
U32 w;
for (w = 1; w < maxW+1; w++) {
rankValPtr[w] = rankVal0[w] >> consumed;
} } } }
HUF_fillDTableX2(dt, maxTableLog,
wksp->sortedSymbol,
wksp->rankStart0, wksp->rankVal, maxW,
tableLog+1);
dtd.tableLog = (BYTE)maxTableLog;
dtd.tableType = 1;
ZSTD_memcpy(DTable, &dtd, sizeof(dtd));
return iSize;
}
FORCE_INLINE_TEMPLATE U32
HUF_decodeSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
{
size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 1 */
ZSTD_memcpy(op, &dt[val].sequence, 2);
BIT_skipBits(DStream, dt[val].nbBits);
return dt[val].length;
}
FORCE_INLINE_TEMPLATE U32
HUF_decodeLastSymbolX2(void* op, BIT_DStream_t* DStream, const HUF_DEltX2* dt, const U32 dtLog)
{
size_t const val = BIT_lookBitsFast(DStream, dtLog); /* note : dtLog >= 1 */
ZSTD_memcpy(op, &dt[val].sequence, 1);
if (dt[val].length==1) {
BIT_skipBits(DStream, dt[val].nbBits);
} else {
if (DStream->bitsConsumed < (sizeof(DStream->bitContainer)*8)) {
BIT_skipBits(DStream, dt[val].nbBits);
if (DStream->bitsConsumed > (sizeof(DStream->bitContainer)*8))
/* ugly hack; works only because it's the last symbol. Note : can't easily extract nbBits from just this symbol */
DStream->bitsConsumed = (sizeof(DStream->bitContainer)*8);
}
}
return 1;
}
#define HUF_DECODE_SYMBOLX2_0(ptr, DStreamPtr) \
do { ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog); } while (0)
#define HUF_DECODE_SYMBOLX2_1(ptr, DStreamPtr) \
do { \
if (MEM_64bits() || (HUF_TABLELOG_MAX<=12)) \
ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog); \
} while (0)
#define HUF_DECODE_SYMBOLX2_2(ptr, DStreamPtr) \
do { \
if (MEM_64bits()) \
ptr += HUF_decodeSymbolX2(ptr, DStreamPtr, dt, dtLog); \
} while (0)
HINT_INLINE size_t
HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
const HUF_DEltX2* const dt, const U32 dtLog)
{
BYTE* const pStart = p;
/* up to 8 symbols at a time */
if ((size_t)(pEnd - p) >= sizeof(bitDPtr->bitContainer)) {
if (dtLog <= 11 && MEM_64bits()) {
/* up to 10 symbols at a time */
while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-9)) {
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
}
} else {
/* up to 8 symbols at a time */
while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p < pEnd-(sizeof(bitDPtr->bitContainer)-1))) {
HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
HUF_DECODE_SYMBOLX2_1(p, bitDPtr);
HUF_DECODE_SYMBOLX2_2(p, bitDPtr);
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
}
}
} else {
BIT_reloadDStream(bitDPtr);
}
/* closer to end : up to 2 symbols at a time */
if ((size_t)(pEnd - p) >= 2) {
while ((BIT_reloadDStream(bitDPtr) == BIT_DStream_unfinished) & (p <= pEnd-2))
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
while (p <= pEnd-2)
HUF_DECODE_SYMBOLX2_0(p, bitDPtr); /* no need to reload : reached the end of DStream */
}
if (p < pEnd)
p += HUF_decodeLastSymbolX2(p, bitDPtr, dt, dtLog);
return p-pStart;
}
FORCE_INLINE_TEMPLATE size_t
HUF_decompress1X2_usingDTable_internal_body(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable)
{
BIT_DStream_t bitD;
/* Init */
CHECK_F( BIT_initDStream(&bitD, cSrc, cSrcSize) );
/* decode */
{ BYTE* const ostart = (BYTE*) dst;
BYTE* const oend = ZSTD_maybeNullPtrAdd(ostart, dstSize);
const void* const dtPtr = DTable+1; /* force compiler to not use strict-aliasing */
const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
DTableDesc const dtd = HUF_getDTableDesc(DTable);
HUF_decodeStreamX2(ostart, &bitD, oend, dt, dtd.tableLog);
}
/* check */
if (!BIT_endOfDStream(&bitD)) return ERROR(corruption_detected);
/* decoded size */
return dstSize;
}
/* HUF_decompress4X2_usingDTable_internal_body():
* Conditions:
* @dstSize >= 6
*/
FORCE_INLINE_TEMPLATE size_t
HUF_decompress4X2_usingDTable_internal_body(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable)
{
if (cSrcSize < 10) return ERROR(corruption_detected); /* strict minimum : jump table + 1 byte per stream */
if (dstSize < 6) return ERROR(corruption_detected); /* stream 4-split doesn't work */
{ const BYTE* const istart = (const BYTE*) cSrc;
BYTE* const ostart = (BYTE*) dst;
BYTE* const oend = ostart + dstSize;
BYTE* const olimit = oend - (sizeof(size_t)-1);
const void* const dtPtr = DTable+1;
const HUF_DEltX2* const dt = (const HUF_DEltX2*)dtPtr;
/* Init */
BIT_DStream_t bitD1;
BIT_DStream_t bitD2;
BIT_DStream_t bitD3;
BIT_DStream_t bitD4;
size_t const length1 = MEM_readLE16(istart);
size_t const length2 = MEM_readLE16(istart+2);
size_t const length3 = MEM_readLE16(istart+4);
size_t const length4 = cSrcSize - (length1 + length2 + length3 + 6);
const BYTE* const istart1 = istart + 6; /* jumpTable */
const BYTE* const istart2 = istart1 + length1;
const BYTE* const istart3 = istart2 + length2;
const BYTE* const istart4 = istart3 + length3;
size_t const segmentSize = (dstSize+3) / 4;
BYTE* const opStart2 = ostart + segmentSize;
BYTE* const opStart3 = opStart2 + segmentSize;
BYTE* const opStart4 = opStart3 + segmentSize;
BYTE* op1 = ostart;
BYTE* op2 = opStart2;
BYTE* op3 = opStart3;
BYTE* op4 = opStart4;
U32 endSignal = 1;
DTableDesc const dtd = HUF_getDTableDesc(DTable);
U32 const dtLog = dtd.tableLog;
if (length4 > cSrcSize) return ERROR(corruption_detected); /* overflow */
if (opStart4 > oend) return ERROR(corruption_detected); /* overflow */
assert(dstSize >= 6 /* validated above */);
CHECK_F( BIT_initDStream(&bitD1, istart1, length1) );
CHECK_F( BIT_initDStream(&bitD2, istart2, length2) );
CHECK_F( BIT_initDStream(&bitD3, istart3, length3) );
CHECK_F( BIT_initDStream(&bitD4, istart4, length4) );
/* 16-32 symbols per loop (4-8 symbols per stream) */
if ((size_t)(oend - op4) >= sizeof(size_t)) {
for ( ; (endSignal) & (op4 < olimit); ) {
#if defined(__clang__) && (defined(__x86_64__) || defined(__i386__))
HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
endSignal &= BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished;
endSignal &= BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished;
HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
endSignal &= BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished;
endSignal &= BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished;
#else
HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
HUF_DECODE_SYMBOLX2_1(op1, &bitD1);
HUF_DECODE_SYMBOLX2_1(op2, &bitD2);
HUF_DECODE_SYMBOLX2_1(op3, &bitD3);
HUF_DECODE_SYMBOLX2_1(op4, &bitD4);
HUF_DECODE_SYMBOLX2_2(op1, &bitD1);
HUF_DECODE_SYMBOLX2_2(op2, &bitD2);
HUF_DECODE_SYMBOLX2_2(op3, &bitD3);
HUF_DECODE_SYMBOLX2_2(op4, &bitD4);
HUF_DECODE_SYMBOLX2_0(op1, &bitD1);
HUF_DECODE_SYMBOLX2_0(op2, &bitD2);
HUF_DECODE_SYMBOLX2_0(op3, &bitD3);
HUF_DECODE_SYMBOLX2_0(op4, &bitD4);
endSignal = (U32)LIKELY((U32)
(BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
& (BIT_reloadDStreamFast(&bitD2) == BIT_DStream_unfinished)
& (BIT_reloadDStreamFast(&bitD3) == BIT_DStream_unfinished)
& (BIT_reloadDStreamFast(&bitD4) == BIT_DStream_unfinished));
#endif
}
}
/* check corruption */
if (op1 > opStart2) return ERROR(corruption_detected);
if (op2 > opStart3) return ERROR(corruption_detected);
if (op3 > opStart4) return ERROR(corruption_detected);
/* note : op4 already verified within main loop */
/* finish bitStreams one by one */
HUF_decodeStreamX2(op1, &bitD1, opStart2, dt, dtLog);
HUF_decodeStreamX2(op2, &bitD2, opStart3, dt, dtLog);
HUF_decodeStreamX2(op3, &bitD3, opStart4, dt, dtLog);
HUF_decodeStreamX2(op4, &bitD4, oend, dt, dtLog);
/* check */
{ U32 const endCheck = BIT_endOfDStream(&bitD1) & BIT_endOfDStream(&bitD2) & BIT_endOfDStream(&bitD3) & BIT_endOfDStream(&bitD4);
if (!endCheck) return ERROR(corruption_detected); }
/* decoded size */
return dstSize;
}
}
#if HUF_NEED_BMI2_FUNCTION
static BMI2_TARGET_ATTRIBUTE
size_t HUF_decompress4X2_usingDTable_internal_bmi2(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif
static
size_t HUF_decompress4X2_usingDTable_internal_default(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
#if ZSTD_ENABLE_ASM_X86_64_BMI2
HUF_ASM_DECL void HUF_decompress4X2_usingDTable_internal_fast_asm_loop(HUF_DecompressFastArgs* args) ZSTDLIB_HIDDEN;
#endif
static HUF_FAST_BMI2_ATTRS
void HUF_decompress4X2_usingDTable_internal_fast_c_loop(HUF_DecompressFastArgs* args)
{
U64 bits[4];
BYTE const* ip[4];
BYTE* op[4];
BYTE* oend[4];
HUF_DEltX2 const* const dtable = (HUF_DEltX2 const*)args->dt;
BYTE const* const ilowest = args->ilowest;
/* Copy the arguments to local registers. */
ZSTD_memcpy(&bits, &args->bits, sizeof(bits));
ZSTD_memcpy((void*)(&ip), &args->ip, sizeof(ip));
ZSTD_memcpy(&op, &args->op, sizeof(op));
oend[0] = op[1];
oend[1] = op[2];
oend[2] = op[3];
oend[3] = args->oend;
assert(MEM_isLittleEndian());
assert(!MEM_32bits());
for (;;) {
BYTE* olimit;
int stream;
/* Assert loop preconditions */
#ifndef NDEBUG
for (stream = 0; stream < 4; ++stream) {
assert(op[stream] <= oend[stream]);
assert(ip[stream] >= ilowest);
}
#endif
/* Compute olimit */
{
/* Each loop does 5 table lookups for each of the 4 streams.
* Each table lookup consumes up to 11 bits of input, and produces
* up to 2 bytes of output.
*/
/* We can consume up to 7 bytes of input per iteration per stream.
* We also know that each input pointer is >= ip[0]. So we can run
* iters loops before running out of input.
*/
size_t iters = (size_t)(ip[0] - ilowest) / 7;
/* Each iteration can produce up to 10 bytes of output per stream.
* Each output stream my advance at different rates. So take the
* minimum number of safe iterations among all the output streams.
*/
for (stream = 0; stream < 4; ++stream) {
size_t const oiters = (size_t)(oend[stream] - op[stream]) / 10;
iters = MIN(iters, oiters);
}
/* Each iteration produces at least 5 output symbols. So until
* op[3] crosses olimit, we know we haven't executed iters
* iterations yet. This saves us maintaining an iters counter,
* at the expense of computing the remaining # of iterations
* more frequently.
*/
olimit = op[3] + (iters * 5);
/* Exit the fast decoding loop once we reach the end. */
if (op[3] == olimit)
break;
/* Exit the decoding loop if any input pointer has crossed the
* previous one. This indicates corruption, and a precondition
* to our loop is that ip[i] >= ip[0].
*/
for (stream = 1; stream < 4; ++stream) {
if (ip[stream] < ip[stream - 1])
goto _out;
}
}
#ifndef NDEBUG
for (stream = 1; stream < 4; ++stream) {
assert(ip[stream] >= ip[stream - 1]);
}
#endif
#define HUF_4X2_DECODE_SYMBOL(_stream, _decode3) \
do { \
if ((_decode3) || (_stream) != 3) { \
int const index = (int)(bits[(_stream)] >> 53); \
HUF_DEltX2 const entry = dtable[index]; \
MEM_write16(op[(_stream)], entry.sequence); \
bits[(_stream)] <<= (entry.nbBits) & 0x3F; \
op[(_stream)] += (entry.length); \
} \
} while (0)
#define HUF_4X2_RELOAD_STREAM(_stream) \
do { \
HUF_4X2_DECODE_SYMBOL(3, 1); \
{ \
int const ctz = ZSTD_countTrailingZeros64(bits[(_stream)]); \
int const nbBits = ctz & 7; \
int const nbBytes = ctz >> 3; \
ip[(_stream)] -= nbBytes; \
bits[(_stream)] = MEM_read64(ip[(_stream)]) | 1; \
bits[(_stream)] <<= nbBits; \
} \
} while (0)
/* Manually unroll the loop because compilers don't consistently
* unroll the inner loops, which destroys performance.
*/
do {
/* Decode 5 symbols from each of the first 3 streams.
* The final stream will be decoded during the reload phase
* to reduce register pressure.
*/
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X2_DECODE_SYMBOL, 0);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X2_DECODE_SYMBOL, 0);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X2_DECODE_SYMBOL, 0);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X2_DECODE_SYMBOL, 0);
HUF_4X_FOR_EACH_STREAM_WITH_VAR(HUF_4X2_DECODE_SYMBOL, 0);
/* Decode one symbol from the final stream */
HUF_4X2_DECODE_SYMBOL(3, 1);
/* Decode 4 symbols from the final stream & reload bitstreams.
* The final stream is reloaded last, meaning that all 5 symbols
* are decoded from the final stream before it is reloaded.
*/
HUF_4X_FOR_EACH_STREAM(HUF_4X2_RELOAD_STREAM);
} while (op[3] < olimit);
}
#undef HUF_4X2_DECODE_SYMBOL
#undef HUF_4X2_RELOAD_STREAM
_out:
/* Save the final values of each of the state variables back to args. */
ZSTD_memcpy(&args->bits, &bits, sizeof(bits));
ZSTD_memcpy((void*)(&args->ip), &ip, sizeof(ip));
ZSTD_memcpy(&args->op, &op, sizeof(op));
}
static HUF_FAST_BMI2_ATTRS size_t
HUF_decompress4X2_usingDTable_internal_fast(
void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
const HUF_DTable* DTable,
HUF_DecompressFastLoopFn loopFn) {
void const* dt = DTable + 1;
const BYTE* const ilowest = (const BYTE*)cSrc;
BYTE* const oend = ZSTD_maybeNullPtrAdd((BYTE*)dst, dstSize);
HUF_DecompressFastArgs args;
{
size_t const ret = HUF_DecompressFastArgs_init(&args, dst, dstSize, cSrc, cSrcSize, DTable);
FORWARD_IF_ERROR(ret, "Failed to init asm args");
if (ret == 0)
return 0;
}
assert(args.ip[0] >= args.ilowest);
loopFn(&args);
/* note : op4 already verified within main loop */
assert(args.ip[0] >= ilowest);
assert(args.ip[1] >= ilowest);
assert(args.ip[2] >= ilowest);
assert(args.ip[3] >= ilowest);
assert(args.op[3] <= oend);
assert(ilowest == args.ilowest);
assert(ilowest + 6 == args.iend[0]);
(void)ilowest;
/* finish bitStreams one by one */
{
size_t const segmentSize = (dstSize+3) / 4;
BYTE* segmentEnd = (BYTE*)dst;
int i;
for (i = 0; i < 4; ++i) {
BIT_DStream_t bit;
if (segmentSize <= (size_t)(oend - segmentEnd))
segmentEnd += segmentSize;
else
segmentEnd = oend;
FORWARD_IF_ERROR(HUF_initRemainingDStream(&bit, &args, i, segmentEnd), "corruption");
args.op[i] += HUF_decodeStreamX2(args.op[i], &bit, segmentEnd, (HUF_DEltX2 const*)dt, HUF_DECODER_FAST_TABLELOG);
if (args.op[i] != segmentEnd)
return ERROR(corruption_detected);
}
}
/* decoded size */
return dstSize;
}
static size_t HUF_decompress4X2_usingDTable_internal(void* dst, size_t dstSize, void const* cSrc,
size_t cSrcSize, HUF_DTable const* DTable, int flags)
{
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X2_usingDTable_internal_default;
HUF_DecompressFastLoopFn loopFn = HUF_decompress4X2_usingDTable_internal_fast_c_loop;
#if DYNAMIC_BMI2
if (flags & HUF_flags_bmi2) {
fallbackFn = HUF_decompress4X2_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X2_usingDTable_internal_fast_asm_loop;
}
# endif
} else {
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
#endif
#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X2_usingDTable_internal_fast_asm_loop;
}
#endif
if (HUF_ENABLE_FAST_DECODE && !(flags & HUF_flags_disableFast)) {
size_t const ret = HUF_decompress4X2_usingDTable_internal_fast(dst, dstSize, cSrc, cSrcSize, DTable, loopFn);
if (ret != 0)
return ret;
}
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
HUF_DGEN(HUF_decompress1X2_usingDTable_internal)
size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* DCtx, void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
void* workSpace, size_t wkspSize, int flags)
{
const BYTE* ip = (const BYTE*) cSrc;
size_t const hSize = HUF_readDTableX2_wksp(DCtx, cSrc, cSrcSize,
workSpace, wkspSize, flags);
if (HUF_isError(hSize)) return hSize;
if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
ip += hSize; cSrcSize -= hSize;
return HUF_decompress1X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, DCtx, flags);
}
static size_t HUF_decompress4X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
void* workSpace, size_t wkspSize, int flags)
{
const BYTE* ip = (const BYTE*) cSrc;
size_t hSize = HUF_readDTableX2_wksp(dctx, cSrc, cSrcSize,
workSpace, wkspSize, flags);
if (HUF_isError(hSize)) return hSize;
if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
ip += hSize; cSrcSize -= hSize;
return HUF_decompress4X2_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, flags);
}
#endif /* HUF_FORCE_DECOMPRESS_X1 */
/* ***********************************/
/* Universal decompression selectors */
/* ***********************************/
#if !defined(HUF_FORCE_DECOMPRESS_X1) && !defined(HUF_FORCE_DECOMPRESS_X2)
typedef struct { U32 tableTime; U32 decode256Time; } algo_time_t;
static const algo_time_t algoTime[16 /* Quantization */][2 /* single, double */] =
{
/* single, double, quad */
{{0,0}, {1,1}}, /* Q==0 : impossible */
{{0,0}, {1,1}}, /* Q==1 : impossible */
{{ 150,216}, { 381,119}}, /* Q == 2 : 12-18% */
{{ 170,205}, { 514,112}}, /* Q == 3 : 18-25% */
{{ 177,199}, { 539,110}}, /* Q == 4 : 25-32% */
{{ 197,194}, { 644,107}}, /* Q == 5 : 32-38% */
{{ 221,192}, { 735,107}}, /* Q == 6 : 38-44% */
{{ 256,189}, { 881,106}}, /* Q == 7 : 44-50% */
{{ 359,188}, {1167,109}}, /* Q == 8 : 50-56% */
{{ 582,187}, {1570,114}}, /* Q == 9 : 56-62% */
{{ 688,187}, {1712,122}}, /* Q ==10 : 62-69% */
{{ 825,186}, {1965,136}}, /* Q ==11 : 69-75% */
{{ 976,185}, {2131,150}}, /* Q ==12 : 75-81% */
{{1180,186}, {2070,175}}, /* Q ==13 : 81-87% */
{{1377,185}, {1731,202}}, /* Q ==14 : 87-93% */
{{1412,185}, {1695,202}}, /* Q ==15 : 93-99% */
};
#endif
/** HUF_selectDecoder() :
* Tells which decoder is likely to decode faster,
* based on a set of pre-computed metrics.
* @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 .
* Assumption : 0 < dstSize <= 128 KB */
U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize)
{
assert(dstSize > 0);
assert(dstSize <= 128*1024);
#if defined(HUF_FORCE_DECOMPRESS_X1)
(void)dstSize;
(void)cSrcSize;
return 0;
#elif defined(HUF_FORCE_DECOMPRESS_X2)
(void)dstSize;
(void)cSrcSize;
return 1;
#else
/* decoder timing evaluation */
{ U32 const Q = (cSrcSize >= dstSize) ? 15 : (U32)(cSrcSize * 16 / dstSize); /* Q < 16 */
U32 const D256 = (U32)(dstSize >> 8);
U32 const DTime0 = algoTime[Q][0].tableTime + (algoTime[Q][0].decode256Time * D256);
U32 DTime1 = algoTime[Q][1].tableTime + (algoTime[Q][1].decode256Time * D256);
DTime1 += DTime1 >> 5; /* small advantage to algorithm using less memory, to reduce cache eviction */
return DTime1 < DTime0;
}
#endif
}
size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize,
const void* cSrc, size_t cSrcSize,
void* workSpace, size_t wkspSize, int flags)
{
/* validation checks */
if (dstSize == 0) return ERROR(dstSize_tooSmall);
if (cSrcSize > dstSize) return ERROR(corruption_detected); /* invalid */
if (cSrcSize == dstSize) { ZSTD_memcpy(dst, cSrc, dstSize); return dstSize; } /* not compressed */
if (cSrcSize == 1) { ZSTD_memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; } /* RLE */
{ U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
#if defined(HUF_FORCE_DECOMPRESS_X1)
(void)algoNb;
assert(algoNb == 0);
return HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
cSrcSize, workSpace, wkspSize, flags);
#elif defined(HUF_FORCE_DECOMPRESS_X2)
(void)algoNb;
assert(algoNb == 1);
return HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
cSrcSize, workSpace, wkspSize, flags);
#else
return algoNb ? HUF_decompress1X2_DCtx_wksp(dctx, dst, dstSize, cSrc,
cSrcSize, workSpace, wkspSize, flags):
HUF_decompress1X1_DCtx_wksp(dctx, dst, dstSize, cSrc,
cSrcSize, workSpace, wkspSize, flags);
#endif
}
}
size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags)
{
DTableDesc const dtd = HUF_getDTableDesc(DTable);
#if defined(HUF_FORCE_DECOMPRESS_X1)
(void)dtd;
assert(dtd.tableType == 0);
return HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#elif defined(HUF_FORCE_DECOMPRESS_X2)
(void)dtd;
assert(dtd.tableType == 1);
return HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#else
return dtd.tableType ? HUF_decompress1X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags) :
HUF_decompress1X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#endif
}
#ifndef HUF_FORCE_DECOMPRESS_X2
size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags)
{
const BYTE* ip = (const BYTE*) cSrc;
size_t const hSize = HUF_readDTableX1_wksp(dctx, cSrc, cSrcSize, workSpace, wkspSize, flags);
if (HUF_isError(hSize)) return hSize;
if (hSize >= cSrcSize) return ERROR(srcSize_wrong);
ip += hSize; cSrcSize -= hSize;
return HUF_decompress1X1_usingDTable_internal(dst, dstSize, ip, cSrcSize, dctx, flags);
}
#endif
size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags)
{
DTableDesc const dtd = HUF_getDTableDesc(DTable);
#if defined(HUF_FORCE_DECOMPRESS_X1)
(void)dtd;
assert(dtd.tableType == 0);
return HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#elif defined(HUF_FORCE_DECOMPRESS_X2)
(void)dtd;
assert(dtd.tableType == 1);
return HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#else
return dtd.tableType ? HUF_decompress4X2_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags) :
HUF_decompress4X1_usingDTable_internal(dst, maxDstSize, cSrc, cSrcSize, DTable, flags);
#endif
}
size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags)
{
/* validation checks */
if (dstSize == 0) return ERROR(dstSize_tooSmall);
if (cSrcSize == 0) return ERROR(corruption_detected);
{ U32 const algoNb = HUF_selectDecoder(dstSize, cSrcSize);
#if defined(HUF_FORCE_DECOMPRESS_X1)
(void)algoNb;
assert(algoNb == 0);
return HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, flags);
#elif defined(HUF_FORCE_DECOMPRESS_X2)
(void)algoNb;
assert(algoNb == 1);
return HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, flags);
#else
return algoNb ? HUF_decompress4X2_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, flags) :
HUF_decompress4X1_DCtx_wksp(dctx, dst, dstSize, cSrc, cSrcSize, workSpace, wkspSize, flags);
#endif
}
}
rust/README.md
+2
View File
@@ -22,6 +22,8 @@ zstd ABI:
- `fse_decompress` builds FSE decoding tables and decodes FSE streams.
- `fse_compress` normalizes counts, writes FSE headers, builds compression
tables, and encodes FSE streams.
- `huf_decompress` builds Huffman decoding tables and decodes X1 and X2
Huffman streams.
- Compression primitives
- `hist` counts byte frequencies for FSE and Huffman compression.
- Runtime support
rust/src/huf_decompress.rs
+1397
View File
@@ -0,0 +1,1397 @@
#![allow(non_snake_case)]
//! Huffman decoding tables and the single/four-stream HUF decoders.
//!
//! This is the Rust implementation of `lib/decompress/huf_decompress.c`.
//! The C version has a second, architecture-specific fast path. The table
//! format and the portable decoder below are shared by both implementations;
//! retaining the portable path keeps the C ABI and bitstream behaviour while
//! avoiding unchecked SIMD/assembly reads in the migration layer.
use crate::bitstream::{
BIT_DStream_status, BIT_DStream_t, BIT_endOfDStream, BIT_initDStream, BIT_lookBitsFast,
BIT_reloadDStream, BIT_skipBits,
};
use crate::entropy_common::{HUF_readStats_wksp, HUF_TABLELOG_MAX};
use crate::errors::{ERR_isError, ZstdErrorCode, ERROR};
use crate::mem::{MEM_32bits, MEM_64bits, MEM_readLE16, MEM_write16};
use std::os::raw::{c_int, c_uint, c_void};
#[cfg(all(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
))]
compile_error!("Huffman X1 and X2 decoder force features are mutually exclusive");
const HUF_SYMBOLVALUE_MAX: usize = 255;
const HUF_DECODER_FAST_TABLELOG: u32 = 11;
const HUF_READ_STATS_WORKSPACE_SIZE_U32: usize = 219;
/* This is the C macro sequence used by both portable fast decode loops:
*
* X2, X1, X2, X0
*
* where X2 only runs on 64-bit targets, X1 runs on 64-bit targets (or with
* HUF_TABLELOG_MAX <= 12), and X0 always runs. Keeping this as data makes
* the 32-bit behaviour explicit: two decodes, not four. */
#[inline]
fn huf_fast_sequence_slots(is_64_bits: bool) -> [bool; 4] {
[
is_64_bits,
is_64_bits || HUF_TABLELOG_MAX <= 12,
is_64_bits,
true,
]
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[allow(dead_code)] // Each variant is constructed only in its feature-selected build.
enum HufForcedDecoder {
X1,
X2,
}
/* `lib/libzstd.mk` maps HUF_FORCE_DECOMPRESS_X{1,2} to these mutually
* exclusive Cargo features. The C and Rust halves must select the same table
* layout, especially in minified builds where X1 is forced by default. */
#[cfg(all(
feature = "huf-force-decompress-x1",
not(feature = "huf-force-decompress-x2")
))]
const fn huf_forced_decoder() -> Option<HufForcedDecoder> {
Some(HufForcedDecoder::X1)
}
#[cfg(all(
feature = "huf-force-decompress-x2",
not(feature = "huf-force-decompress-x1")
))]
const fn huf_forced_decoder() -> Option<HufForcedDecoder> {
Some(HufForcedDecoder::X2)
}
#[cfg(not(any(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
)))]
const fn huf_forced_decoder() -> Option<HufForcedDecoder> {
None
}
/* These are the C `sizeof()` values on every supported ABI: all fields are
* byte or four-byte aligned. The caller-owned workspace is part of the C
* contract, so preserve the exact rejection thresholds even though the Rust
* implementation keeps its scratch state on the stack. */
const HUF_READ_DTABLE_X1_WORKSPACE_SIZE: usize = (HUF_TABLELOG_MAX as usize + 1) * 4
+ (HUF_TABLELOG_MAX as usize + 1) * 4
+ HUF_READ_STATS_WORKSPACE_SIZE_U32 * 4
+ (HUF_SYMBOLVALUE_MAX + 1)
+ (HUF_SYMBOLVALUE_MAX + 1);
const HUF_READ_DTABLE_X2_WORKSPACE_SIZE: usize =
HUF_TABLELOG_MAX as usize * (HUF_TABLELOG_MAX as usize + 1) * 4
+ (HUF_TABLELOG_MAX as usize + 1) * 4
+ (HUF_TABLELOG_MAX as usize + 3) * 4
+ (HUF_SYMBOLVALUE_MAX + 1)
+ (HUF_SYMBOLVALUE_MAX + 1)
+ HUF_READ_STATS_WORKSPACE_SIZE_U32 * 4;
#[derive(Copy, Clone, Debug)]
struct DTableDesc {
max_table_log: u8,
table_type: u8,
table_log: u8,
reserved: u8,
}
#[repr(C)]
#[derive(Copy, Clone)]
struct HufDEltX2 {
sequence: u16,
nb_bits: u8,
length: u8,
}
#[inline]
unsafe fn get_dtable_desc(table: *const u32) -> DTableDesc {
let bytes = table.cast::<u8>();
DTableDesc {
max_table_log: bytes.read(),
table_type: bytes.add(1).read(),
table_log: bytes.add(2).read(),
reserved: bytes.add(3).read(),
}
}
#[inline]
unsafe fn set_dtable_desc(table: *mut u32, desc: DTableDesc) {
let bytes = table.cast::<u8>();
bytes.write(desc.max_table_log);
bytes.add(1).write(desc.table_type);
bytes.add(2).write(desc.table_log);
bytes.add(3).write(desc.reserved);
}
#[inline]
unsafe fn x1_entry(table: *const u32, index: usize) -> (u8, u8) {
let entry = table.add(1).cast::<u8>().add(index * 2);
(entry.read(), entry.add(1).read())
}
#[inline]
unsafe fn set_x1_entry(table: *mut u32, index: usize, nb_bits: u8, symbol: u8) {
let entry = table.add(1).cast::<u8>().add(index * 2);
entry.write(nb_bits);
entry.add(1).write(symbol);
}
#[inline]
unsafe fn x2_entry(table: *const u32, index: usize) -> HufDEltX2 {
table.add(1).cast::<HufDEltX2>().add(index).read_unaligned()
}
#[inline]
unsafe fn set_x2_raw(table: *mut u32, index: usize, raw: u32) {
table
.add(1)
.cast::<HufDEltX2>()
.add(index)
.cast::<u32>()
.write_unaligned(raw);
}
#[inline]
fn huf_rescale_stats(
huff_weight: &mut [u8; HUF_SYMBOLVALUE_MAX + 1],
rank_val: &mut [u32; HUF_TABLELOG_MAX as usize + 1],
nb_symbols: usize,
table_log: u32,
target_table_log: u32,
) -> u32 {
if table_log > target_table_log {
return table_log;
}
if table_log < target_table_log {
let scale = target_table_log - table_log;
for weight in huff_weight.iter_mut().take(nb_symbols) {
if *weight != 0 {
*weight = weight.wrapping_add(scale as u8);
}
}
for symbol in ((scale + 1)..=target_table_log).rev() {
rank_val[symbol as usize] = rank_val[(symbol - scale) as usize];
}
for symbol in (1..=scale).rev() {
rank_val[symbol as usize] = 0;
}
}
target_table_log
}
#[no_mangle]
pub unsafe extern "C" fn HUF_readDTableX1_wksp(
dtable: *mut u32,
src: *const c_void,
src_size: usize,
_work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
if wksp_size < HUF_READ_DTABLE_X1_WORKSPACE_SIZE {
return ERROR(ZstdErrorCode::TableLogTooLarge);
}
let mut rank_val = [0u32; HUF_TABLELOG_MAX as usize + 1];
let mut huff_weight = [0u8; HUF_SYMBOLVALUE_MAX + 1];
let mut stats_wksp = [0u32; HUF_READ_STATS_WORKSPACE_SIZE_U32];
let mut nb_symbols = 0u32;
let mut table_log = 0u32;
let i_size = HUF_readStats_wksp(
huff_weight.as_mut_ptr(),
huff_weight.len(),
rank_val.as_mut_ptr(),
&mut nb_symbols,
&mut table_log,
src,
src_size,
stats_wksp.as_mut_ptr().cast::<c_void>(),
std::mem::size_of_val(&stats_wksp),
flags,
);
if ERR_isError(i_size) {
return i_size;
}
let mut desc = get_dtable_desc(dtable);
let max_table_log = u32::from(desc.max_table_log) + 1;
let target_table_log = max_table_log.min(HUF_DECODER_FAST_TABLELOG);
table_log = huf_rescale_stats(
&mut huff_weight,
&mut rank_val,
nb_symbols as usize,
table_log,
target_table_log,
);
if table_log > max_table_log {
return ERROR(ZstdErrorCode::TableLogTooLarge);
}
desc.table_type = 0;
desc.table_log = table_log as u8;
set_dtable_desc(dtable, desc);
let mut rank_start = [0u32; HUF_TABLELOG_MAX as usize + 1];
let mut next_rank_start = 0u32;
for weight in 0..=table_log as usize {
rank_start[weight] = next_rank_start;
next_rank_start = next_rank_start.wrapping_add(rank_val[weight]);
}
let mut symbols = [0u8; HUF_SYMBOLVALUE_MAX + 1];
for (symbol, weight) in huff_weight
.iter()
.copied()
.take(nb_symbols as usize)
.enumerate()
{
let weight = weight as usize;
let index = rank_start[weight] as usize;
symbols[index] = symbol as u8;
rank_start[weight] = rank_start[weight].wrapping_add(1);
}
let mut symbol = rank_val[0] as usize;
let mut rank_start_index = 0usize;
for (weight, symbol_count) in rank_val
.iter()
.copied()
.take(table_log as usize + 1)
.enumerate()
.skip(1)
{
let symbol_count = symbol_count as usize;
let length = (1usize << weight) >> 1;
let nb_bits = (table_log as usize + 1 - weight) as u8;
for item in 0..symbol_count {
let value = symbols[symbol + item];
for entry in 0..length {
set_x1_entry(dtable, rank_start_index + entry, nb_bits, value);
}
rank_start_index += length;
}
symbol += symbol_count;
}
i_size
}
#[inline]
fn build_delt_x2_u32(symbol: u32, nb_bits: u32, base_seq: u16, level: u32) -> u32 {
if cfg!(target_endian = "little") {
let sequence = if level == 1 {
symbol
} else {
u32::from(base_seq) + (symbol << 8)
};
sequence + (nb_bits << 16) + (level << 24)
} else {
let sequence = if level == 1 {
symbol << 8
} else {
(u32::from(base_seq) << 8) + symbol
};
(sequence << 16) + (nb_bits << 8) + level
}
}
#[allow(clippy::too_many_arguments)]
unsafe fn fill_dtable_x2_for_weight(
dtable: *mut u32,
table_offset: usize,
sorted_symbols: &[u8; HUF_SYMBOLVALUE_MAX + 1],
begin: usize,
end: usize,
nb_bits: u32,
table_log: u32,
base_seq: u16,
level: u32,
) {
let length = 1usize << (table_log - nb_bits);
let mut out = table_offset;
for symbol in sorted_symbols.iter().take(end).skip(begin) {
let entry = build_delt_x2_u32(u32::from(*symbol), nb_bits, base_seq, level);
for _ in 0..length {
set_x2_raw(dtable, out, entry);
out += 1;
}
}
}
#[allow(clippy::too_many_arguments)]
unsafe fn fill_dtable_x2_level2(
dtable: *mut u32,
table_offset: usize,
target_log: u32,
consumed_bits: u32,
rank_val: &[u32; HUF_TABLELOG_MAX as usize + 1],
min_weight: usize,
max_weight1: usize,
sorted_symbols: &[u8; HUF_SYMBOLVALUE_MAX + 1],
rank_start: &[u32; HUF_TABLELOG_MAX as usize + 3],
nb_bits_baseline: u32,
base_seq: u16,
) {
if min_weight > 1 {
let skip_size = rank_val[min_weight] as usize;
let entry = build_delt_x2_u32(u32::from(base_seq), consumed_bits, 0, 1);
for index in 0..skip_size {
set_x2_raw(dtable, table_offset + index, entry);
}
}
for weight in min_weight..max_weight1 {
let begin = rank_start[weight] as usize;
let end = rank_start[weight + 1] as usize;
let nb_bits = nb_bits_baseline - weight as u32;
fill_dtable_x2_for_weight(
dtable,
table_offset + rank_val[weight] as usize,
sorted_symbols,
begin,
end,
nb_bits + consumed_bits,
target_log,
base_seq,
2,
);
}
}
unsafe fn fill_dtable_x2(
dtable: *mut u32,
target_log: u32,
sorted_symbols: &[u8; HUF_SYMBOLVALUE_MAX + 1],
rank_start: &[u32; HUF_TABLELOG_MAX as usize + 3],
rank_val_origin: &[[u32; HUF_TABLELOG_MAX as usize + 1]; HUF_TABLELOG_MAX as usize],
max_weight: u32,
nb_bits_baseline: u32,
) {
let rank_val = &rank_val_origin[0];
let scale_log = nb_bits_baseline as i32 - target_log as i32;
let min_bits = nb_bits_baseline - max_weight;
for weight in 1..=max_weight as usize {
let begin = rank_start[weight] as usize;
let end = rank_start[weight + 1] as usize;
let nb_bits = nb_bits_baseline - weight as u32;
if target_log - nb_bits >= min_bits {
let mut start = rank_val[weight] as usize;
let length = 1usize << (target_log - nb_bits);
let mut min_weight = nb_bits as i32 + scale_log;
if min_weight < 1 {
min_weight = 1;
}
for symbol in sorted_symbols.iter().take(end).skip(begin) {
fill_dtable_x2_level2(
dtable,
start,
target_log,
nb_bits,
&rank_val_origin[nb_bits as usize],
min_weight as usize,
max_weight as usize + 1,
sorted_symbols,
rank_start,
nb_bits_baseline,
u16::from(*symbol),
);
start += length;
}
} else {
fill_dtable_x2_for_weight(
dtable,
rank_val[weight] as usize,
sorted_symbols,
begin,
end,
nb_bits,
target_log,
0,
1,
);
}
}
}
#[no_mangle]
pub unsafe extern "C" fn HUF_readDTableX2_wksp(
dtable: *mut u32,
src: *const c_void,
src_size: usize,
_work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
if wksp_size < HUF_READ_DTABLE_X2_WORKSPACE_SIZE {
return ERROR(ZstdErrorCode::Generic);
}
let mut desc = get_dtable_desc(dtable);
let mut max_table_log = u32::from(desc.max_table_log);
if max_table_log > HUF_TABLELOG_MAX {
return ERROR(ZstdErrorCode::TableLogTooLarge);
}
let mut rank_stats = [0u32; HUF_TABLELOG_MAX as usize + 1];
let mut weight_list = [0u8; HUF_SYMBOLVALUE_MAX + 1];
let mut stats_wksp = [0u32; HUF_READ_STATS_WORKSPACE_SIZE_U32];
let mut nb_symbols = 0u32;
let mut table_log = 0u32;
let i_size = HUF_readStats_wksp(
weight_list.as_mut_ptr(),
weight_list.len(),
rank_stats.as_mut_ptr(),
&mut nb_symbols,
&mut table_log,
src,
src_size,
stats_wksp.as_mut_ptr().cast::<c_void>(),
std::mem::size_of_val(&stats_wksp),
flags,
);
if ERR_isError(i_size) {
return i_size;
}
if table_log > max_table_log {
return ERROR(ZstdErrorCode::TableLogTooLarge);
}
if table_log <= HUF_DECODER_FAST_TABLELOG && max_table_log > HUF_DECODER_FAST_TABLELOG {
max_table_log = HUF_DECODER_FAST_TABLELOG;
}
let mut max_weight = table_log as usize;
while rank_stats[max_weight] == 0 {
max_weight -= 1;
}
/* `rank_start` deliberately has the leading pad from the C workspace.
* The table builder consumes the padded view after the sorting pass. */
let mut rank_start = [0u32; HUF_TABLELOG_MAX as usize + 3];
let mut next_rank_start = 0u32;
for weight in 1..=max_weight {
let current = next_rank_start;
next_rank_start = next_rank_start.wrapping_add(rank_stats[weight]);
rank_start[weight + 1] = current;
}
rank_start[1] = next_rank_start;
rank_start[max_weight + 2] = next_rank_start;
let mut sorted_symbols = [0u8; HUF_SYMBOLVALUE_MAX + 1];
for (symbol, weight) in weight_list
.iter()
.copied()
.take(nb_symbols as usize)
.enumerate()
{
let weight = weight as usize;
let index = rank_start[weight + 1] as usize;
sorted_symbols[index] = symbol as u8;
rank_start[weight + 1] = rank_start[weight + 1].wrapping_add(1);
}
rank_start[1] = 0;
let mut rank_val = [[0u32; HUF_TABLELOG_MAX as usize + 1]; HUF_TABLELOG_MAX as usize];
let rescale = max_table_log as i32 - table_log as i32 - 1;
let mut next_rank_val = 0u32;
for weight in 1..=max_weight {
let current = next_rank_val;
let shift = (weight as i32 + rescale) as u32;
next_rank_val = next_rank_val.wrapping_add(rank_stats[weight] << shift);
rank_val[0][weight] = current;
}
let min_bits = table_log + 1 - max_weight as u32;
let base_rank_val = rank_val[0];
for consumed in min_bits..(max_table_log - min_bits + 1) {
for (target, source) in rank_val[consumed as usize]
.iter_mut()
.zip(base_rank_val)
.take(max_weight + 1)
.skip(1)
{
*target = source >> consumed;
}
}
fill_dtable_x2(
dtable,
max_table_log,
&sorted_symbols,
&rank_start,
&rank_val,
max_weight as u32,
table_log + 1,
);
desc.table_log = max_table_log as u8;
desc.table_type = 1;
set_dtable_desc(dtable, desc);
i_size
}
#[inline]
unsafe fn decode_symbol_x1(
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
) -> u8 {
let value = BIT_lookBitsFast(bit_stream, table_log);
let (nb_bits, symbol) = x1_entry(dtable, value);
BIT_skipBits(bit_stream, u32::from(nb_bits));
symbol
}
#[inline]
unsafe fn decode_x1_fast_sequence(
mut out: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
is_64_bits: bool,
) -> *mut u8 {
let slots = huf_fast_sequence_slots(is_64_bits);
if slots[0] {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
if slots[1] {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
if slots[2] {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
if slots[3] {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
out
}
unsafe fn decode_stream_x1(
mut out: *mut u8,
out_end: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
) -> usize {
let out_start = out;
if out_end.offset_from(out) > 3 {
while BIT_reloadDStream(bit_stream) == BIT_DStream_status::Unfinished
&& out < out_end.sub(3)
{
out = decode_x1_fast_sequence(out, bit_stream, dtable, table_log, MEM_64bits());
}
} else {
BIT_reloadDStream(bit_stream);
}
if MEM_32bits() {
while BIT_reloadDStream(bit_stream) == BIT_DStream_status::Unfinished && out < out_end {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
}
while out < out_end {
*out = decode_symbol_x1(bit_stream, dtable, table_log);
out = out.add(1);
}
out.offset_from(out_start) as usize
}
#[inline]
unsafe fn decode_symbol_x2(
out: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
) -> usize {
let value = BIT_lookBitsFast(bit_stream, table_log);
let entry = x2_entry(dtable, value);
MEM_write16(out.cast::<c_void>(), entry.sequence);
BIT_skipBits(bit_stream, u32::from(entry.nb_bits));
entry.length as usize
}
#[inline]
unsafe fn decode_x2_fast_sequence(
mut out: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
is_64_bits: bool,
) -> *mut u8 {
let slots = huf_fast_sequence_slots(is_64_bits);
if slots[0] {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
if slots[1] {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
if slots[2] {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
if slots[3] {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
out
}
#[inline]
unsafe fn decode_last_symbol_x2(
out: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
) -> usize {
let value = BIT_lookBitsFast(bit_stream, table_log);
let entry = x2_entry(dtable, value);
*out = if cfg!(target_endian = "little") {
entry.sequence as u8
} else {
(entry.sequence >> 8) as u8
};
if entry.length == 1 {
BIT_skipBits(bit_stream, u32::from(entry.nb_bits));
} else if (*bit_stream).bitsConsumed < usize::BITS {
BIT_skipBits(bit_stream, u32::from(entry.nb_bits));
if (*bit_stream).bitsConsumed > usize::BITS {
(*bit_stream).bitsConsumed = usize::BITS;
}
}
1
}
unsafe fn decode_stream_x2(
mut out: *mut u8,
out_end: *mut u8,
bit_stream: *mut BIT_DStream_t,
dtable: *const u32,
table_log: u32,
) -> usize {
let out_start = out;
let word_size = std::mem::size_of::<usize>();
if out_end.offset_from(out) as usize >= word_size {
if table_log <= HUF_DECODER_FAST_TABLELOG && MEM_64bits() {
while BIT_reloadDStream(bit_stream) == BIT_DStream_status::Unfinished
&& out_end.offset_from(out) > 9
{
for _ in 0..5 {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
}
} else {
while BIT_reloadDStream(bit_stream) == BIT_DStream_status::Unfinished
&& out < out_end.sub(word_size - 1)
{
out = decode_x2_fast_sequence(out, bit_stream, dtable, table_log, MEM_64bits());
}
}
} else {
BIT_reloadDStream(bit_stream);
}
if out_end.offset_from(out) as usize >= 2 {
while BIT_reloadDStream(bit_stream) == BIT_DStream_status::Unfinished
&& out <= out_end.sub(2)
{
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
while out <= out_end.sub(2) {
out = out.add(decode_symbol_x2(out, bit_stream, dtable, table_log));
}
}
if out < out_end {
out = out.add(decode_last_symbol_x2(out, bit_stream, dtable, table_log));
}
out.offset_from(out_start) as usize
}
unsafe fn decompress_1x1_using_dtable(
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
) -> usize {
let mut bit_stream = std::mem::zeroed::<BIT_DStream_t>();
let init = BIT_initDStream(&mut bit_stream, src, src_size);
if ERR_isError(init) {
return init;
}
let out = dst.cast::<u8>();
decode_stream_x1(
out,
out.add(dst_size),
&mut bit_stream,
dtable,
u32::from(get_dtable_desc(dtable).table_log),
);
if BIT_endOfDStream(&bit_stream) == 0 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
dst_size
}
unsafe fn decompress_1x2_using_dtable(
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
) -> usize {
let mut bit_stream = std::mem::zeroed::<BIT_DStream_t>();
let init = BIT_initDStream(&mut bit_stream, src, src_size);
if ERR_isError(init) {
return init;
}
let out = dst.cast::<u8>();
decode_stream_x2(
out,
out.add(dst_size),
&mut bit_stream,
dtable,
u32::from(get_dtable_desc(dtable).table_log),
);
if BIT_endOfDStream(&bit_stream) == 0 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
dst_size
}
unsafe fn split_4x_input(
src: *const c_void,
src_size: usize,
) -> Result<([*const u8; 4], [usize; 4]), usize> {
if src_size < 10 {
return Err(ERROR(ZstdErrorCode::CorruptionDetected));
}
let input = src.cast::<u8>();
let length1 = MEM_readLE16(input.cast::<c_void>()) as usize;
let length2 = MEM_readLE16(input.add(2).cast::<c_void>()) as usize;
let length3 = MEM_readLE16(input.add(4).cast::<c_void>()) as usize;
let header_and_streams = match length1
.checked_add(length2)
.and_then(|value| value.checked_add(length3))
.and_then(|value| value.checked_add(6))
{
Some(value) if value <= src_size => value,
_ => return Err(ERROR(ZstdErrorCode::CorruptionDetected)),
};
let length4 = src_size - header_and_streams;
let stream1 = input.add(6);
let stream2 = stream1.add(length1);
let stream3 = stream2.add(length2);
let stream4 = stream3.add(length3);
Ok((
[stream1, stream2, stream3, stream4],
[length1, length2, length3, length4],
))
}
unsafe fn decompress_4x1_using_dtable(
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
) -> usize {
if dst_size < 6 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
let (streams, lengths) = match split_4x_input(src, src_size) {
Ok(value) => value,
Err(error) => return error,
};
let segment_size = match dst_size.checked_add(3) {
Some(size) => size / 4,
None => return ERROR(ZstdErrorCode::CorruptionDetected),
};
let out = dst.cast::<u8>();
let table_log = u32::from(get_dtable_desc(dtable).table_log);
for stream in 0..4 {
let start = match segment_size.checked_mul(stream) {
Some(offset) if offset <= dst_size => out.add(offset),
_ => return ERROR(ZstdErrorCode::CorruptionDetected),
};
let end_offset = (segment_size.saturating_mul(stream + 1)).min(dst_size);
let end = out.add(end_offset);
let mut bit_stream = std::mem::zeroed::<BIT_DStream_t>();
let init = BIT_initDStream(
&mut bit_stream,
streams[stream].cast::<c_void>(),
lengths[stream],
);
if ERR_isError(init) {
return init;
}
decode_stream_x1(start, end, &mut bit_stream, dtable, table_log);
if BIT_endOfDStream(&bit_stream) == 0 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
}
dst_size
}
unsafe fn decompress_4x2_using_dtable(
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
) -> usize {
if dst_size < 6 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
let (streams, lengths) = match split_4x_input(src, src_size) {
Ok(value) => value,
Err(error) => return error,
};
let segment_size = match dst_size.checked_add(3) {
Some(size) => size / 4,
None => return ERROR(ZstdErrorCode::CorruptionDetected),
};
let out = dst.cast::<u8>();
let table_log = u32::from(get_dtable_desc(dtable).table_log);
for stream in 0..4 {
let start = match segment_size.checked_mul(stream) {
Some(offset) if offset <= dst_size => out.add(offset),
_ => return ERROR(ZstdErrorCode::CorruptionDetected),
};
let end_offset = (segment_size.saturating_mul(stream + 1)).min(dst_size);
let end = out.add(end_offset);
let mut bit_stream = std::mem::zeroed::<BIT_DStream_t>();
let init = BIT_initDStream(
&mut bit_stream,
streams[stream].cast::<c_void>(),
lengths[stream],
);
if ERR_isError(init) {
return init;
}
decode_stream_x2(start, end, &mut bit_stream, dtable, table_log);
if BIT_endOfDStream(&bit_stream) == 0 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
}
dst_size
}
const ALGO_TIME: [[(u32, u32); 2]; 16] = [
[(0, 0), (1, 1)],
[(0, 0), (1, 1)],
[(150, 216), (381, 119)],
[(170, 205), (514, 112)],
[(177, 199), (539, 110)],
[(197, 194), (644, 107)],
[(221, 192), (735, 107)],
[(256, 189), (881, 106)],
[(359, 188), (1167, 109)],
[(582, 187), (1570, 114)],
[(688, 187), (1712, 122)],
[(825, 186), (1965, 136)],
[(976, 185), (2131, 150)],
[(1180, 186), (2070, 175)],
[(1377, 185), (1731, 202)],
[(1412, 185), (1695, 202)],
];
#[no_mangle]
pub extern "C" fn HUF_selectDecoder(dst_size: usize, c_src_size: usize) -> c_uint {
if let Some(decoder) = huf_forced_decoder() {
return match decoder {
HufForcedDecoder::X1 => 0,
HufForcedDecoder::X2 => 1,
};
}
if dst_size == 0 {
return 0;
}
let quantization = if c_src_size >= dst_size {
15
} else {
c_src_size.saturating_mul(16) / dst_size
};
let decode_256 = (dst_size >> 8) as u32;
let (table0, decode0) = ALGO_TIME[quantization][0];
let (table1, decode1) = ALGO_TIME[quantization][1];
let time0 = table0.wrapping_add(decode0.wrapping_mul(decode_256));
let mut time1 = table1.wrapping_add(decode1.wrapping_mul(decode_256));
time1 = time1.wrapping_add(time1 >> 5);
(time1 < time0) as c_uint
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress1X_usingDTable(
dst: *mut c_void,
max_dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
_flags: c_int,
) -> usize {
let table_type = get_dtable_desc(dtable).table_type;
match huf_forced_decoder() {
Some(HufForcedDecoder::X1) => {
debug_assert_eq!(table_type, 0);
decompress_1x1_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
Some(HufForcedDecoder::X2) => {
debug_assert_ne!(table_type, 0);
decompress_1x2_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
None if table_type != 0 => {
decompress_1x2_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
None => decompress_1x1_using_dtable(dst, max_dst_size, src, src_size, dtable),
}
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress4X_usingDTable(
dst: *mut c_void,
max_dst_size: usize,
src: *const c_void,
src_size: usize,
dtable: *const u32,
_flags: c_int,
) -> usize {
let table_type = get_dtable_desc(dtable).table_type;
match huf_forced_decoder() {
Some(HufForcedDecoder::X1) => {
debug_assert_eq!(table_type, 0);
decompress_4x1_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
Some(HufForcedDecoder::X2) => {
debug_assert_ne!(table_type, 0);
decompress_4x2_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
None if table_type != 0 => {
decompress_4x2_using_dtable(dst, max_dst_size, src, src_size, dtable)
}
None => decompress_4x1_using_dtable(dst, max_dst_size, src, src_size, dtable),
}
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress1X1_DCtx_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
let header_size = HUF_readDTableX1_wksp(dctx, src, src_size, work_space, wksp_size, flags);
if ERR_isError(header_size) {
return header_size;
}
if header_size >= src_size {
return ERROR(ZstdErrorCode::SrcSizeWrong);
}
decompress_1x1_using_dtable(
dst,
dst_size,
src.cast::<u8>().add(header_size).cast::<c_void>(),
src_size - header_size,
dctx,
)
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress1X2_DCtx_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
let header_size = HUF_readDTableX2_wksp(dctx, src, src_size, work_space, wksp_size, flags);
if ERR_isError(header_size) {
return header_size;
}
if header_size >= src_size {
return ERROR(ZstdErrorCode::SrcSizeWrong);
}
decompress_1x2_using_dtable(
dst,
dst_size,
src.cast::<u8>().add(header_size).cast::<c_void>(),
src_size - header_size,
dctx,
)
}
#[allow(clippy::too_many_arguments)]
unsafe fn decompress_4x1_dctx_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
let header_size = HUF_readDTableX1_wksp(dctx, src, src_size, work_space, wksp_size, flags);
if ERR_isError(header_size) {
return header_size;
}
if header_size >= src_size {
return ERROR(ZstdErrorCode::SrcSizeWrong);
}
decompress_4x1_using_dtable(
dst,
dst_size,
src.cast::<u8>().add(header_size).cast::<c_void>(),
src_size - header_size,
dctx,
)
}
#[allow(clippy::too_many_arguments)]
unsafe fn decompress_4x2_dctx_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
let header_size = HUF_readDTableX2_wksp(dctx, src, src_size, work_space, wksp_size, flags);
if ERR_isError(header_size) {
return header_size;
}
if header_size >= src_size {
return ERROR(ZstdErrorCode::SrcSizeWrong);
}
decompress_4x2_using_dtable(
dst,
dst_size,
src.cast::<u8>().add(header_size).cast::<c_void>(),
src_size - header_size,
dctx,
)
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress1X_DCtx_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
if dst_size == 0 {
return ERROR(ZstdErrorCode::DstSizeTooSmall);
}
if src_size > dst_size {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
if src_size == dst_size {
std::ptr::copy_nonoverlapping(src.cast::<u8>(), dst.cast::<u8>(), dst_size);
return dst_size;
}
if src_size == 1 {
std::ptr::write_bytes(dst.cast::<u8>(), *src.cast::<u8>(), dst_size);
return dst_size;
}
if HUF_selectDecoder(dst_size, src_size) != 0 {
HUF_decompress1X2_DCtx_wksp(
dctx, dst, dst_size, src, src_size, work_space, wksp_size, flags,
)
} else {
HUF_decompress1X1_DCtx_wksp(
dctx, dst, dst_size, src, src_size, work_space, wksp_size, flags,
)
}
}
#[no_mangle]
pub unsafe extern "C" fn HUF_decompress4X_hufOnly_wksp(
dctx: *mut u32,
dst: *mut c_void,
dst_size: usize,
src: *const c_void,
src_size: usize,
work_space: *mut c_void,
wksp_size: usize,
flags: c_int,
) -> usize {
if dst_size == 0 {
return ERROR(ZstdErrorCode::DstSizeTooSmall);
}
if src_size == 0 {
return ERROR(ZstdErrorCode::CorruptionDetected);
}
if HUF_selectDecoder(dst_size, src_size) != 0 {
decompress_4x2_dctx_wksp(
dctx, dst, dst_size, src, src_size, work_space, wksp_size, flags,
)
} else {
decompress_4x1_dctx_wksp(
dctx, dst, dst_size, src, src_size, work_space, wksp_size, flags,
)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::bitstream::{BIT_CStream_t, BIT_addBits, BIT_closeCStream, BIT_initCStream};
#[cfg(not(any(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
)))]
use crate::bitstream::{BIT_DStream_t, BIT_initDStream};
#[cfg(not(feature = "huf-force-decompress-x2"))]
fn x1_table_for_binary_alphabet() -> [u32; 2] {
/* maxTableLog=1, type=X1, tableLog=1. Each X1 entry is
* { nbBits, symbol }, and the table consumes the two words after the
* descriptor exactly like HUF_CREATE_STATIC_DTABLEX1(). */
[0x0101_0001, 0x0101_0001]
}
fn encoded_binary_symbols(symbols: &[u8]) -> ([u8; 32], usize) {
let mut compressed = [0u8; 32];
let mut stream = unsafe { std::mem::zeroed::<BIT_CStream_t>() };
assert_eq!(
unsafe {
BIT_initCStream(
&mut stream,
compressed.as_mut_ptr().cast::<c_void>(),
compressed.len(),
)
},
0
);
for symbol in symbols.iter().rev() {
unsafe { BIT_addBits(&mut stream, usize::from(*symbol), 1) };
}
let compressed_size = unsafe { BIT_closeCStream(&mut stream) };
assert_ne!(compressed_size, 0);
(compressed, compressed_size)
}
#[cfg(not(feature = "huf-force-decompress-x2"))]
#[test]
fn x1_using_dtable_decodes_a_bitstream_written_by_the_c_compatible_writer() {
let dtable = x1_table_for_binary_alphabet();
let expected = [0u8, 1, 1, 0, 1, 0, 0, 1];
let (compressed, compressed_size) = encoded_binary_symbols(&expected);
let mut output = [0u8; 8];
let result = unsafe {
HUF_decompress1X_usingDTable(
output.as_mut_ptr().cast::<c_void>(),
output.len(),
compressed.as_ptr().cast::<c_void>(),
compressed_size,
dtable.as_ptr(),
0,
)
};
assert_eq!(result, output.len());
assert_eq!(output, expected);
}
#[cfg(not(feature = "huf-force-decompress-x1"))]
#[test]
fn x2_using_dtable_decodes_a_binary_stream_and_preserves_the_two_byte_layout() {
/* maxTableLog=1, type=X2, tableLog=1. The two entries each decode
* exactly one symbol, exercising the final-symbol path as well. */
let dtable = [0x0101_0101, 0x0101_0000, 0x0101_0001];
let expected = [1u8, 0, 1, 1, 0, 0, 1];
let (compressed, compressed_size) = encoded_binary_symbols(&expected);
let mut output = [0u8; 7];
let result = unsafe {
HUF_decompress1X_usingDTable(
output.as_mut_ptr().cast::<c_void>(),
output.len(),
compressed.as_ptr().cast::<c_void>(),
compressed_size,
dtable.as_ptr(),
0,
)
};
assert_eq!(result, output.len());
assert_eq!(output, expected);
}
#[test]
fn x1_table_builder_expands_a_reference_c_header() {
/* Header emitted by the C HUF table writer for weights [1, 1, 2]. */
let header = [129u8, 0x11];
let mut dtable = [0x0b00_000b_u32; 1 + (1 << 11)];
let mut workspace = [0u8; 2560];
let result = unsafe {
HUF_readDTableX1_wksp(
dtable.as_mut_ptr(),
header.as_ptr().cast::<c_void>(),
header.len(),
workspace.as_mut_ptr().cast::<c_void>(),
workspace.len(),
0,
)
};
assert_eq!(result, header.len());
let desc = unsafe { get_dtable_desc(dtable.as_ptr()) };
assert_eq!(
(desc.max_table_log, desc.table_type, desc.table_log),
(11, 0, 11)
);
assert_eq!(unsafe { x1_entry(dtable.as_ptr(), 0) }, (2, 0));
assert_eq!(unsafe { x1_entry(dtable.as_ptr(), 511) }, (2, 0));
assert_eq!(unsafe { x1_entry(dtable.as_ptr(), 512) }, (2, 1));
assert_eq!(unsafe { x1_entry(dtable.as_ptr(), 1024) }, (1, 2));
}
#[test]
fn table_builders_preserve_workspace_error_contracts() {
let header = [129u8, 0x11];
let mut x1 = [0x0b00_000b_u32; 1 + (1 << 11)];
let mut x2 = [0x0c00_000c_u32; 1 + (1 << 12)];
let mut workspace = [0u8; 2560];
let x1_error = unsafe {
HUF_readDTableX1_wksp(
x1.as_mut_ptr(),
header.as_ptr().cast::<c_void>(),
header.len(),
workspace.as_mut_ptr().cast::<c_void>(),
HUF_READ_DTABLE_X1_WORKSPACE_SIZE - 1,
0,
)
};
assert_eq!(x1_error, ERROR(ZstdErrorCode::TableLogTooLarge));
let x2_error = unsafe {
HUF_readDTableX2_wksp(
x2.as_mut_ptr(),
header.as_ptr().cast::<c_void>(),
header.len(),
workspace.as_mut_ptr().cast::<c_void>(),
HUF_READ_DTABLE_X2_WORKSPACE_SIZE - 1,
0,
)
};
assert_eq!(x2_error, ERROR(ZstdErrorCode::Generic));
}
#[cfg(not(any(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
)))]
#[test]
fn selector_matches_the_reference_timing_table() {
assert_eq!(HUF_selectDecoder(128 * 1024, 16 * 1024), 1);
assert_eq!(HUF_selectDecoder(128 * 1024, 128 * 1024), 0);
}
#[test]
fn forced_decoder_feature_controls_the_public_selector() {
#[cfg(feature = "huf-force-decompress-x1")]
{
assert_eq!(huf_forced_decoder(), Some(HufForcedDecoder::X1));
assert_eq!(HUF_selectDecoder(128 * 1024, 16 * 1024), 0);
}
#[cfg(feature = "huf-force-decompress-x2")]
{
assert_eq!(huf_forced_decoder(), Some(HufForcedDecoder::X2));
assert_eq!(HUF_selectDecoder(128 * 1024, 128 * 1024), 1);
}
#[cfg(not(any(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
)))]
{
assert_eq!(huf_forced_decoder(), None);
}
}
#[test]
fn portable_fast_sequences_match_the_c_32_and_64_bit_macro_guards() {
assert_eq!(huf_fast_sequence_slots(false), [false, true, false, true]);
assert_eq!(huf_fast_sequence_slots(true), [true, true, true, true]);
}
#[cfg(not(any(
feature = "huf-force-decompress-x1",
feature = "huf-force-decompress-x2"
)))]
#[test]
fn simulated_32_bit_fast_sequences_decode_only_the_c_permitted_two_symbols() {
let expected = [0u8, 1, 1, 0];
let (compressed, compressed_size) = encoded_binary_symbols(&expected);
let x1_dtable = x1_table_for_binary_alphabet();
let mut x1_stream = unsafe { std::mem::zeroed::<BIT_DStream_t>() };
assert_eq!(
unsafe {
BIT_initDStream(
&mut x1_stream,
compressed.as_ptr().cast::<c_void>(),
compressed_size,
)
},
compressed_size
);
let mut x1_output = [0xa5u8; 4];
let x1_end = unsafe {
decode_x1_fast_sequence(
x1_output.as_mut_ptr(),
&mut x1_stream,
x1_dtable.as_ptr(),
1,
false,
)
};
assert_eq!(unsafe { x1_end.offset_from(x1_output.as_mut_ptr()) }, 2);
assert_eq!(&x1_output[..2], &expected[..2]);
assert_eq!(&x1_output[2..], &[0xa5, 0xa5]);
/* Each X2 entry emits two bytes. A 32-bit fast sequence must take
* only the X1 and X0 slots, so it advances four bytes, rather than
* the eight bytes four X2 decodes would produce. */
let x2_dtable = [0x0101_0101, 0x0201_0100, 0x0201_0001];
let mut x2_stream = unsafe { std::mem::zeroed::<BIT_DStream_t>() };
assert_eq!(
unsafe {
BIT_initDStream(
&mut x2_stream,
compressed.as_ptr().cast::<c_void>(),
compressed_size,
)
},
compressed_size
);
let mut x2_output = [0xa5u8; 8];
let x2_end = unsafe {
decode_x2_fast_sequence(
x2_output.as_mut_ptr(),
&mut x2_stream,
x2_dtable.as_ptr(),
1,
false,
)
};
assert_eq!(unsafe { x2_end.offset_from(x2_output.as_mut_ptr()) }, 4);
assert_eq!(&x2_output[..4], &expected);
assert_eq!(&x2_output[4..], &[0xa5, 0xa5, 0xa5, 0xa5]);
}
}
rust/src/lib.rs
+1
View File
@@ -10,6 +10,7 @@ pub mod errors;
pub mod fse_compress;
pub mod fse_decompress;
pub mod hist;
pub mod huf_decompress;
pub mod mem;
pub mod pool;
pub mod threading;