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minor speed optimization : index overflow prevention

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new code supposed to be easier to auto-vectorize
This commit is contained in:
Yann Collet 2017-12-29 14:40:33 +01:00
parent ffc335bccf
commit f36da5b4d9
1 changed files with 46 additions and 35 deletions
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81
lib/compress/zstd_compress.c
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@ -59,18 +59,16 @@ ZSTD_CCtx* ZSTD_createCCtx(void)
ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem) ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
{ {
ZSTD_CCtx* cctx;
if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
cctx = (ZSTD_CCtx*) ZSTD_calloc(sizeof(ZSTD_CCtx), customMem);
if (!cctx) return NULL;
cctx->customMem = customMem;
cctx->requestedParams.compressionLevel = ZSTD_CLEVEL_DEFAULT;
cctx->requestedParams.fParams.contentSizeFlag = 1;
ZSTD_STATIC_ASSERT(zcss_init==0); ZSTD_STATIC_ASSERT(zcss_init==0);
ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1)); ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_UNKNOWN==(0ULL - 1));
return cctx; if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
{ ZSTD_CCtx* const cctx = (ZSTD_CCtx*)ZSTD_calloc(sizeof(ZSTD_CCtx), customMem);
if (!cctx) return NULL;
cctx->customMem = customMem;
cctx->requestedParams.compressionLevel = ZSTD_CLEVEL_DEFAULT;
cctx->requestedParams.fParams.contentSizeFlag = 1;
return cctx;
}
} }
ZSTD_CCtx* ZSTD_initStaticCCtx(void *workspace, size_t workspaceSize) ZSTD_CCtx* ZSTD_initStaticCCtx(void *workspace, size_t workspaceSize)
@ -95,13 +93,10 @@ size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx)
{ {
if (cctx==NULL) return 0; /* support free on NULL */ if (cctx==NULL) return 0; /* support free on NULL */
if (cctx->staticSize) return ERROR(memory_allocation); /* not compatible with static CCtx */ if (cctx->staticSize) return ERROR(memory_allocation); /* not compatible with static CCtx */
ZSTD_free(cctx->workSpace, cctx->customMem); ZSTD_free(cctx->workSpace, cctx->customMem); cctx->workSpace = NULL;
cctx->workSpace = NULL; ZSTD_freeCDict(cctx->cdictLocal); cctx->cdictLocal = NULL;
ZSTD_freeCDict(cctx->cdictLocal);
cctx->cdictLocal = NULL;
#ifdef ZSTD_MULTITHREAD #ifdef ZSTD_MULTITHREAD
ZSTDMT_freeCCtx(cctx->mtctx); ZSTDMT_freeCCtx(cctx->mtctx); cctx->mtctx = NULL;
cctx->mtctx = NULL;
#endif #endif
ZSTD_free(cctx, cctx->customMem); ZSTD_free(cctx, cctx->customMem);
return 0; /* reserved as a potential error code in the future */ return 0; /* reserved as a potential error code in the future */
@ -122,10 +117,6 @@ static size_t ZSTD_sizeof_mtctx(const ZSTD_CCtx* cctx)
size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx) size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx)
{ {
if (cctx==NULL) return 0; /* support sizeof on NULL */ if (cctx==NULL) return 0; /* support sizeof on NULL */
DEBUGLOG(3, "sizeof(*cctx) : %u", (U32)sizeof(*cctx));
DEBUGLOG(3, "workSpaceSize (including streaming buffers): %u", (U32)cctx->workSpaceSize);
DEBUGLOG(3, "inner cdict : %u", (U32)ZSTD_sizeof_CDict(cctx->cdictLocal));
DEBUGLOG(3, "inner MTCTX : %u", (U32)ZSTD_sizeof_mtctx(cctx));
return sizeof(*cctx) + cctx->workSpaceSize return sizeof(*cctx) + cctx->workSpaceSize
+ ZSTD_sizeof_CDict(cctx->cdictLocal) + ZSTD_sizeof_CDict(cctx->cdictLocal)
+ ZSTD_sizeof_mtctx(cctx); + ZSTD_sizeof_mtctx(cctx);
@ -1085,15 +1076,31 @@ size_t ZSTD_copyCCtx(ZSTD_CCtx* dstCCtx, const ZSTD_CCtx* srcCCtx, unsigned long
} }
#define ZSTD_ROWSIZE 16
/*! ZSTD_reduceTable_internal() :
* reduce table indexes by `reducerValue`
* presume table size is a multiple of ZSTD_ROWSIZE.
* Helps auto-vectorization */
static void ZSTD_reduceTable_internal (U32* const table, int const nbRows, U32 const reducerValue)
{
int cellNb = 0;
int rowNb;
for (rowNb=0 ; rowNb < nbRows ; rowNb++) {
int column;
for (column=0; column<ZSTD_ROWSIZE; column++) {
if (table[cellNb] < reducerValue) table[cellNb] = 0;
else table[cellNb] -= reducerValue;
cellNb++;
} }
}
/*! ZSTD_reduceTable() : /*! ZSTD_reduceTable() :
* reduce table indexes by `reducerValue` */ * reduce table indexes by `reducerValue` */
static void ZSTD_reduceTable (U32* const table, U32 const size, U32 const reducerValue) static void ZSTD_reduceTable (U32* const table, U32 const size, U32 const reducerValue)
{ {
U32 u; assert((size & (ZSTD_ROWSIZE-1)) == 0); /* multiple of ZSTD_ROWSIZE */
for (u=0 ; u < size ; u++) { assert(size < (1U<<31)); /* can be casted to int */
if (table[u] < reducerValue) table[u] = 0; ZSTD_reduceTable_internal(table, size/ZSTD_ROWSIZE, reducerValue);
else table[u] -= reducerValue;
}
} }
/*! ZSTD_ldm_reduceTable() : /*! ZSTD_ldm_reduceTable() :
@ -1112,19 +1119,23 @@ static void ZSTD_ldm_reduceTable(ldmEntry_t* const table, U32 const size,
* rescale all indexes to avoid future overflow (indexes are U32) */ * rescale all indexes to avoid future overflow (indexes are U32) */
static void ZSTD_reduceIndex (ZSTD_CCtx* zc, const U32 reducerValue) static void ZSTD_reduceIndex (ZSTD_CCtx* zc, const U32 reducerValue)
{ {
{ U32 const hSize = (U32)1 << zc->appliedParams.cParams.hashLog; { U32 const hSize = (U32)1 << zc->appliedParams.cParams.hashLog;
ZSTD_reduceTable(zc->hashTable, hSize, reducerValue); } ZSTD_reduceTable(zc->hashTable, hSize, reducerValue);
}
{ U32 const chainSize = (zc->appliedParams.cParams.strategy == ZSTD_fast) ? 0 : ((U32)1 << zc->appliedParams.cParams.chainLog); if (zc->appliedParams.cParams.strategy != ZSTD_fast) {
ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue); } U32 const chainSize = (U32)1 << zc->appliedParams.cParams.chainLog;
ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue);
}
{ U32 const h3Size = (zc->hashLog3) ? (U32)1 << zc->hashLog3 : 0; if (zc->hashLog3) {
ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue); } U32 const h3Size = (U32)1 << zc->hashLog3;
ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue);
}
{ if (zc->appliedParams.ldmParams.enableLdm) { if (zc->appliedParams.ldmParams.enableLdm) {
U32 const ldmHSize = (U32)1 << zc->appliedParams.ldmParams.hashLog; U32 const ldmHSize = (U32)1 << zc->appliedParams.ldmParams.hashLog;
ZSTD_ldm_reduceTable(zc->ldmState.hashTable, ldmHSize, reducerValue); ZSTD_ldm_reduceTable(zc->ldmState.hashTable, ldmHSize, reducerValue);
}
} }
} }