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added ZSTD_duplicateCCtx()

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This commit is contained in:
Yann Collet
2016-01-07 15:35:18 +01:00
parent 494c786a3b
commit ecd651bd91
7 changed files with 119 additions and 53 deletions
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lib/zstd_static.h
+17 -19
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@@ -33,9 +33,9 @@
#ifndef ZSTD_STATIC_H
#define ZSTD_STATIC_H
/* The objects defined into this file should be considered experimental.
* They are not labelled stable, as their prototype may change in the future.
* You can use them for tests, provide feedback, or if you can endure risk of future changes.
/* The objects defined into this file shall be considered experimental.
* They are not considered stable, as their prototype may change in the future.
* You can use them for tests, provide feedback, or if you can endure risks of future changes.
*/
#if defined (__cplusplus)
@@ -108,40 +108,33 @@ ZSTDLIB_API size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
const void* dict,size_t dictSize,
ZSTD_parameters params);
/** Decompression context management */
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
/** ZSTD_decompressDCtx
* Same as ZSTD_decompress, with pre-allocated DCtx structure */
ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
/** ZSTD_decompress_usingDict
* Same as ZSTD_decompressDCtx, using a Dictionary content as prefix
* Note : dict can be NULL, in which case, it's equivalent to ZSTD_decompressDCtx() */
ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* ctx,
void* dst, size_t maxDstSize,
const void* src, size_t srcSize,
const void* dict, size_t dictSize);
const void* src, size_t srcSize,
const void* dict,size_t dictSize);
/* **************************************
* Streaming functions (direct mode)
****************************************/
ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize, int compressionLevel);
ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* ctx, void* dst, size_t maxDstSize, ZSTD_parameters params);
ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* ctx, ZSTD_parameters params);
ZSTDLIB_API size_t ZSTD_compress_insertDictionary(ZSTD_CCtx* ctx, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_duplicateCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx);
ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize);
/**
Streaming compression, direct mode (bufferless)
Streaming compression, synchronous mode (bufferless)
A ZSTD_CCtx object is required to track streaming operations.
Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage it.
A ZSTD_CCtx object can be re-used multiple times.
ZSTD_CCtx object can be re-used multiple times within successive compression operations.
First operation is to start a new frame.
Use ZSTD_compressBegin().
@@ -151,8 +144,13 @@ ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t maxDstSiz
Note that dictionary presence is a "hidden" information,
the decoder needs to be aware that it is required for proper decoding, or decoding will fail.
If you want to compress multiple messages using same dictionary,
it can be beneficial to duplicate compression context rather than reloading dictionary each time.
In such case, use ZSTD_duplicateCCtx(), which will need an already created ZSTD_CCtx,
in order to duplicate compression context into it.
Then, consume your input using ZSTD_compressContinue().
The interface is synchronous, so all input will be consumed.
The interface is synchronous, so all input will be consumed and produce a compressed output.
You must ensure there is enough space in destination buffer to store compressed data under worst case scenario.
Worst case evaluation is provided by ZSTD_compressBound().