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added ZSTD_clampCParams()

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now ZSTD_adjustCParams() is always successful,
it always produces a valid CParams
This commit is contained in:
Yann Collet 2017-06-16 17:29:35 -07:00
parent aee916e37c
commit 381e66cfbd
3 changed files with 35 additions and 10 deletions
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37
lib/compress/zstd_compress.c
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@ -433,8 +433,8 @@ void ZSTD_CCtx_reset(ZSTD_CCtx* cctx)
cctx->cdict = NULL;
}
/** ZSTD_checkParams() :
ensure param values remain within authorized range.
/** ZSTD_checkCParams() :
control CParam values remain within authorized range.
@return : 0, or an error code if one value is beyond authorized range */
size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
{
@ -448,6 +448,25 @@ size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
return 0;
}
/** ZSTD_clampCParams() :
* make CParam values within valid range.
* @return : valid CParams */
static ZSTD_compressionParameters ZSTD_clampCParams(ZSTD_compressionParameters cParams)
{
# define CLAMP(val,min,max) { \
if (val<min) val=min; \
else if (val>max) val=max; \
}
CLAMP(cParams.windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
CLAMP(cParams.chainLog, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
CLAMP(cParams.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
CLAMP(cParams.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
CLAMP(cParams.searchLength, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
CLAMP(cParams.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
if ((U32)(cParams.strategy) > (U32)ZSTD_btultra) cParams.strategy = ZSTD_btultra;
return cParams;
}
/** ZSTD_cycleLog() :
* condition for correct operation : hashLog > 1 */
static U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
@ -456,14 +475,15 @@ static U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
return hashLog - btScale;
}
/** ZSTD_adjustCParams() :
/** ZSTD_adjustCParams_internal() :
optimize `cPar` for a given input (`srcSize` and `dictSize`).
mostly downsizing to reduce memory consumption and initialization.
Both `srcSize` and `dictSize` are optional (use 0 if unknown),
but if both are 0, no optimization can be done.
Note : cPar is considered validated at this stage. Use ZSTD_checkParams() to ensure that. */
ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
ZSTD_compressionParameters ZSTD_adjustCParams_internal(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
{
assert(ZSTD_checkCParams(cPar)==0);
if (srcSize+dictSize == 0) return cPar; /* no size information available : no adjustment */
/* resize params, to use less memory when necessary */
@ -483,6 +503,12 @@ ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, u
return cPar;
}
ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
{
cPar = ZSTD_clampCParams(cPar);
return ZSTD_adjustCParams_internal(cPar, srcSize, dictSize);
}
size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams)
{
@ -3989,8 +4015,7 @@ ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long l
if (cp.chainLog > ZSTD_CHAINLOG_MAX) cp.chainLog = ZSTD_CHAINLOG_MAX;
if (cp.hashLog > ZSTD_HASHLOG_MAX) cp.hashLog = ZSTD_HASHLOG_MAX;
}
cp = ZSTD_adjustCParams(cp, srcSizeHint, dictSize);
return cp;
return ZSTD_adjustCParams_internal(cp, srcSizeHint, dictSize); /* no need to ensure initial CParams validity */
}
/*! ZSTD_getParams() :

4
lib/compress/zstdmt_compress.c
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@ -190,7 +190,7 @@ static ZSTDMT_CCtxPool* ZSTDMT_createCCtxPool(unsigned nbThreads,
cctxPool->availCCtx = 1; /* at least one cctx for single-thread mode */
cctxPool->cctx[0] = ZSTD_createCCtx_advanced(cMem);
if (!cctxPool->cctx[0]) { ZSTDMT_freeCCtxPool(cctxPool); return NULL; }
DEBUGLOG(1, "cctxPool created, with %u threads", nbThreads);
DEBUGLOG(3, "cctxPool created, with %u threads", nbThreads);
return cctxPool;
}
@ -458,7 +458,7 @@ size_t ZSTDMT_compressCCtx(ZSTDMT_CCtx* mtctx,
size_t frameStartPos = 0, dstBufferPos = 0;
DEBUGLOG(3, "windowLog : %2u => chunkTargetSize : %u bytes ", params.cParams.windowLog, (U32)chunkTargetSize);
DEBUGLOG(2, "nbChunks : %2u (chunkSize : %u bytes) ", nbChunks, (U32)avgChunkSize);
DEBUGLOG(3, "nbChunks : %2u (chunkSize : %u bytes) ", nbChunks, (U32)avgChunkSize);
params.fParams.contentSizeFlag = 1;
if (nbChunks==1) { /* fallback to single-thread mode */

4
lib/zstd.h
View File

@ -589,8 +589,8 @@ ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long l
ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
/*! ZSTD_adjustCParams() :
* optimize params for a given `srcSize` and `dictSize`.
* both values are optional, select `0` if unknown. */
* optimize params for a given `srcSize` and `dictSize`.
* both values are optional, select `0` if unknown. */
ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
/*! ZSTD_compress_advanced() :