diff options
| -rw-r--r-- | lib/lz4hc.c | 52 | ||||
| -rw-r--r-- | lib/lz4hc.h | 2 |
2 files changed, 39 insertions, 15 deletions
diff --git a/lib/lz4hc.c b/lib/lz4hc.c index 60690a0..388eb40 100644 --- a/lib/lz4hc.c +++ b/lib/lz4hc.c @@ -619,22 +619,46 @@ static int LZ4HC_compress_generic ( limitedOutput_directive limit ) { + typedef enum { lz4hc, lz4opt } lz4hc_strat_e; + typedef struct { + lz4hc_strat_e strat; + U32 nbSearches; + U32 targetLength; + } cParams_t; + static const cParams_t clTable[LZ4HC_CLEVEL_MAX+1] = { + { lz4hc, 2, 16 }, /* 0, unused */ + { lz4hc, 2, 16 }, /* 1, unused */ + { lz4hc, 2, 16 }, /* 2, unused */ + { lz4hc, 4, 16 }, /* 3 */ + { lz4hc, 8, 16 }, /* 4 */ + { lz4hc, 16, 16 }, /* 5 */ + { lz4hc, 32, 16 }, /* 6 */ + { lz4hc, 64, 16 }, /* 7 */ + { lz4hc, 128, 16 }, /* 8 */ + { lz4hc, 256, 16 }, /* 9 */ + { lz4opt, 96, 64 }, /*10==LZ4HC_CLEVEL_OPT_MIN*/ + { lz4opt, 512,128 }, /*11 */ + { lz4opt,8192, LZ4_OPT_NUM }, /* 12==LZ4HC_CLEVEL_MAX */ + }; + ctx->end += *srcSizePtr; if (cLevel < 1) cLevel = LZ4HC_CLEVEL_DEFAULT; /* note : convention is different from lz4frame, maybe something to review */ - if (cLevel > 9) { - if (limit == limitedDestSize) cLevel = 10; - switch (cLevel) { - case 10: - return LZ4HC_compress_hashChain(ctx, src, dst, srcSizePtr, dstCapacity, 1<<12, limit); - case 11: - return LZ4HC_compress_optimal(ctx, src, dst, *srcSizePtr, dstCapacity, limit, 512, 128, 0); - default: - /* fall-through */ - case 12: - return LZ4HC_compress_optimal(ctx, src, dst, *srcSizePtr, dstCapacity, limit, 1<<13, LZ4_OPT_NUM, 1); - } + cLevel = MIN(LZ4HC_CLEVEL_MAX, cLevel); + if (limit == limitedDestSize) + cLevel = MIN(LZ4HC_CLEVEL_OPT_MIN-1, cLevel); /* no limitedDestSize variant for lz4opt */ + assert(cLevel >= 0); + assert(cLevel <= LZ4HC_CLEVEL_MAX); + { cParams_t const cParam = clTable[cLevel]; + if (cParam.strat == lz4hc) + return LZ4HC_compress_hashChain(ctx, + src, dst, srcSizePtr, dstCapacity, + cParam.nbSearches, limit); + assert(cParam.strat == lz4opt); + return LZ4HC_compress_optimal(ctx, + src, dst, *srcSizePtr, dstCapacity, limit, + cParam.nbSearches, cParam.targetLength, + cLevel == LZ4HC_CLEVEL_MAX); /* ultra mode */ } - return LZ4HC_compress_hashChain(ctx, src, dst, srcSizePtr, dstCapacity, 1 << (cLevel-1), limit); /* levels 1-9 */ } @@ -667,7 +691,7 @@ int LZ4_compress_HC(const char* src, char* dst, int srcSize, int dstCapacity, in } /* LZ4_compress_HC_destSize() : - * only compatible with Hash Chain match finder */ + * only compatible with regular HC parser */ int LZ4_compress_HC_destSize(void* LZ4HC_Data, const char* source, char* dest, int* sourceSizePtr, int targetDestSize, int cLevel) { LZ4HC_CCtx_internal* const ctx = &((LZ4_streamHC_t*)LZ4HC_Data)->internal_donotuse; diff --git a/lib/lz4hc.h b/lib/lz4hc.h index d791062..d41bf42 100644 --- a/lib/lz4hc.h +++ b/lib/lz4hc.h @@ -46,7 +46,7 @@ extern "C" { /* --- Useful constants --- */ #define LZ4HC_CLEVEL_MIN 3 #define LZ4HC_CLEVEL_DEFAULT 9 -#define LZ4HC_CLEVEL_OPT_MIN 11 +#define LZ4HC_CLEVEL_OPT_MIN 10 #define LZ4HC_CLEVEL_MAX 12 |