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compress uses less memory for small blocks

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This commit is contained in:
Yann Collet 2015-12-02 14:00:45 +01:00
parent a308259afa
commit 120230b895
1 changed files with 12 additions and 9 deletions
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21
lib/zstd_compress.c
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@ -100,8 +100,6 @@ static void ZSTD_resetSeqStore(seqStore_t* ssPtr)
/* ************************************* /* *************************************
* Context memory management * Context memory management
***************************************/ ***************************************/
#define WORKPLACESIZE (BLOCKSIZE*3)
struct ZSTD_CCtx_s struct ZSTD_CCtx_s
{ {
const BYTE* nextSrc; /* next block here to continue on current prefix */ const BYTE* nextSrc; /* next block here to continue on current prefix */
@ -113,6 +111,7 @@ struct ZSTD_CCtx_s
ZSTD_parameters params; ZSTD_parameters params;
void* workSpace; void* workSpace;
size_t workSpaceSize; size_t workSpaceSize;
size_t blockSize;
seqStore_t seqStore; /* sequences storage ptrs */ seqStore_t seqStore; /* sequences storage ptrs */
U32* hashTable; U32* hashTable;
@ -170,11 +169,14 @@ void ZSTD_validateParams(ZSTD_parameters* params)
static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc, static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
ZSTD_parameters params) ZSTD_parameters params)
{ {
/* note : params considered validated here */
const size_t blockSize = MIN(BLOCKSIZE, (size_t)1 << params.windowLog);
/* reserve table memory */ /* reserve table memory */
{ {
const U32 contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog; const U32 contentLog = (params.strategy == ZSTD_fast) ? 1 : params.contentLog;
const size_t tableSpace = ((1 << contentLog) + (1 << params.hashLog)) * sizeof(U32); const size_t tableSpace = ((1 << contentLog) + (1 << params.hashLog)) * sizeof(U32);
const size_t neededSpace = tableSpace + WORKPLACESIZE; const size_t neededSpace = tableSpace + (3*blockSize);
if (zc->workSpaceSize < neededSpace) if (zc->workSpaceSize < neededSpace)
{ {
free(zc->workSpace); free(zc->workSpace);
@ -195,12 +197,13 @@ static size_t ZSTD_resetCCtx_advanced (ZSTD_CCtx* zc,
zc->dictLimit = 0; zc->dictLimit = 0;
zc->lowLimit = 0; zc->lowLimit = 0;
zc->params = params; zc->params = params;
zc->blockSize = blockSize;
zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer); zc->seqStore.offsetStart = (U32*) (zc->seqStore.buffer);
zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart + (BLOCKSIZE>>2)); zc->seqStore.offCodeStart = (BYTE*) (zc->seqStore.offsetStart + (blockSize>>2));
zc->seqStore.litStart = zc->seqStore.offCodeStart + (BLOCKSIZE>>2); zc->seqStore.litStart = zc->seqStore.offCodeStart + (blockSize>>2);
zc->seqStore.litLengthStart = zc->seqStore.litStart + BLOCKSIZE; zc->seqStore.litLengthStart = zc->seqStore.litStart + blockSize;
zc->seqStore.matchLengthStart = zc->seqStore.litLengthStart + (BLOCKSIZE>>2); zc->seqStore.matchLengthStart = zc->seqStore.litLengthStart + (blockSize>>2);
zc->seqStore.dumpsStart = zc->seqStore.matchLengthStart + (BLOCKSIZE>>2); zc->seqStore.dumpsStart = zc->seqStore.matchLengthStart + (blockSize>>2);
return 0; return 0;
} }
@ -1919,7 +1922,7 @@ static size_t ZSTD_compress_generic (ZSTD_CCtx* ctxPtr,
void* dst, size_t maxDstSize, void* dst, size_t maxDstSize,
const void* src, size_t srcSize) const void* src, size_t srcSize)
{ {
size_t blockSize = BLOCKSIZE; size_t blockSize = ctxPtr->blockSize;
size_t remaining = srcSize; size_t remaining = srcSize;
const BYTE* ip = (const BYTE*)src; const BYTE* ip = (const BYTE*)src;
BYTE* const ostart = (BYTE*)dst; BYTE* const ostart = (BYTE*)dst;