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favorDecSpeed feature can be triggered from lz4frame

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and lz4hc.
This commit is contained in:
Yann Collet 2018-04-26 15:18:44 -07:00
parent 1148173c5d
commit 3792d00168
4 changed files with 27 additions and 11 deletions
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3
lib/lz4frame.c
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@ -612,6 +612,9 @@ size_t LZ4F_compressBegin_usingCDict(LZ4F_cctx* cctxPtr,
/* frame init only for blockLinked : blockIndependent will be init at each block */
LZ4F_applyCDict(cctxPtr->lz4CtxPtr, cdict, cctxPtr->prefs.compressionLevel);
}
if (preferencesPtr->compressionLevel >= LZ4HC_CLEVEL_MIN) {
LZ4_favorDecompressionSpeed(cctxPtr->lz4CtxPtr, preferencesPtr->favorDecSpeed);
}
/* Magic Number */
LZ4F_writeLE32(dstPtr, LZ4F_MAGICNUMBER);

9
lib/lz4frame.h
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@ -173,13 +173,14 @@ typedef struct {
/*! LZ4F_preferences_t :
* makes it possible to supply detailed compression parameters to the stream interface.
* It's not required to set all fields, as long as the structure was initially memset() to zero.
* Structure is presumed initially memset() to zero, representing default settings.
* All reserved fields must be set to zero. */
typedef struct {
LZ4F_frameInfo_t frameInfo;
int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
unsigned autoFlush; /* 1 == always flush, to reduce usage of internal buffers */
unsigned reserved[4]; /* must be zero for forward compatibility */
int compressionLevel; /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
unsigned autoFlush; /* 1: always flush, to reduce usage of internal buffers */
unsigned favorDecSpeed; /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4LZ4HC_CLEVEL_OPT_MIN) */ /* >= v1.8.2 */
unsigned reserved[3]; /* must be zero for forward compatibility */
} LZ4F_preferences_t;
LZ4FLIB_API int LZ4F_compressionLevel_max(void);

8
lib/lz4hc.c
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@ -876,6 +876,11 @@ void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLev
LZ4_streamHCPtr->internal_donotuse.compressionLevel = compressionLevel;
}
void LZ4_favorDecompressionSpeed(LZ4_streamHC_t* LZ4_streamHCPtr, int favor)
{
LZ4_streamHCPtr->internal_donotuse.favorDecSpeed = (favor!=0);
}
int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, const char* dictionary, int dictSize)
{
LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
@ -1120,7 +1125,7 @@ static int LZ4HC_compress_optimal (
const limitedOutput_directive limit,
int const fullUpdate,
const dictCtx_directive dict,
HCfavor_e favorDecSpeed
const HCfavor_e favorDecSpeed
)
{
#define TRAILING_LITERALS 3
@ -1136,7 +1141,6 @@ static int LZ4HC_compress_optimal (
BYTE* oend = op + dstCapacity;
/* init */
favorDecSpeed = favorCompressionRatio;
DEBUGLOG(5, "LZ4HC_compress_optimal");
*srcSizePtr = 0;
if (limit == limitedDestSize) oend -= LASTLITERALS; /* Hack for support LZ4 format restriction */

18
lib/lz4hc.h
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@ -152,7 +152,8 @@ struct LZ4HC_CCtx_internal
uint32_t dictLimit; /* below that point, need extDict */
uint32_t lowLimit; /* below that point, no more dict */
uint32_t nextToUpdate; /* index from which to continue dictionary update */
int compressionLevel;
short compressionLevel;
short favorDecSpeed;
const LZ4HC_CCtx_internal* dictCtx;
};
@ -169,7 +170,8 @@ struct LZ4HC_CCtx_internal
unsigned int dictLimit; /* below that point, need extDict */
unsigned int lowLimit; /* below that point, no more dict */
unsigned int nextToUpdate; /* index from which to continue dictionary update */
int compressionLevel;
short compressionLevel;
short favorDecSpeed;
const LZ4HC_CCtx_internal* dictCtx;
};
@ -253,9 +255,9 @@ LZ4_DEPRECATED("use LZ4_resetStreamHC() instead") LZ4LIB_API int LZ4_resetStr
* `srcSizePtr` : value will be updated to indicate how much bytes were read from `src`
*/
int LZ4_compress_HC_destSize(void* LZ4HC_Data,
const char* src, char* dst,
int* srcSizePtr, int targetDstSize,
int compressionLevel);
const char* src, char* dst,
int* srcSizePtr, int targetDstSize,
int compressionLevel);
/*! LZ4_compress_HC_continue_destSize() : v1.8.0 (experimental)
* Similar as LZ4_compress_HC_continue(),
@ -275,6 +277,12 @@ int LZ4_compress_HC_continue_destSize(LZ4_streamHC_t* LZ4_streamHCPtr,
*/
void LZ4_setCompressionLevel(LZ4_streamHC_t* LZ4_streamHCPtr, int compressionLevel);
/*! LZ4_favorDecompressionSpeed() : v1.8.2 (experimental)
* Parser will select decisions favoring decompression over compression ratio.
* Only work at highest compression settings (level >= LZ4HC_CLEVEL_OPT_MIN)
*/
void LZ4_favorDecompressionSpeed(LZ4_streamHC_t* LZ4_streamHCPtr, int favor);
/*! LZ4_resetStreamHC_fast() :
* When an LZ4_streamHC_t is known to be in a internally coherent state,
* it can often be prepared for a new compression with almost no work, only