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author | Yann Collet <yann.collet.73@gmail.com> | 2014-10-22 07:07:56 (GMT) |
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committer | Yann Collet <yann.collet.73@gmail.com> | 2014-10-22 07:07:56 (GMT) |
commit | e2c84118f52cefe48fd2f751e66ad3ecd904f7b9 (patch) | |
tree | 999f2203e31867aaeaf8f77e6d625a159da60161 /lz4hc.c | |
parent | e468a4eb96ec8e2ea0fc61b5aa20f56a3b214c0e (diff) | |
download | lz4-e2c84118f52cefe48fd2f751e66ad3ecd904f7b9.zip lz4-e2c84118f52cefe48fd2f751e66ad3ecd904f7b9.tar.gz lz4-e2c84118f52cefe48fd2f751e66ad3ecd904f7b9.tar.bz2 |
Added : HC streaming ring buffer example
Diffstat (limited to 'lz4hc.c')
-rwxr-xr-x | lz4hc.c | 70 |
1 files changed, 49 insertions, 21 deletions
@@ -379,6 +379,21 @@ FORCE_INLINE void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip) } +static void LZ4HC_setExternalDict(LZ4HC_Data_Structure* ctxPtr, const BYTE* newBlock) +{ + if (ctxPtr->end >= ctxPtr->base + 4) + LZ4HC_Insert (ctxPtr, ctxPtr->end-3); // finish referencing dictionary content + // Note : need to handle risk of index overflow + // Use only one memory segment for dict, so any previous External Dict is lost at this stage + ctxPtr->lowLimit = ctxPtr->dictLimit; + ctxPtr->dictLimit = (U32)(ctxPtr->end - ctxPtr->base); + ctxPtr->dictBase = ctxPtr->base; + ctxPtr->base = newBlock - ctxPtr->dictLimit; + ctxPtr->end = newBlock; + ctxPtr->nextToUpdate = ctxPtr->dictLimit; // reference table must skip to from beginning of block +} + + static size_t LZ4HC_CommonLength (const BYTE* p1, const BYTE* p2, const BYTE* const p1Limit) { const BYTE* const p1Start = p1; @@ -397,21 +412,6 @@ static size_t LZ4HC_CommonLength (const BYTE* p1, const BYTE* p2, const BYTE* co } -static void LZ4HC_setExternalDict(LZ4HC_Data_Structure* ctxPtr, const BYTE* newBlock) -{ - if (ctxPtr->end >= ctxPtr->base + 4) - LZ4HC_Insert (ctxPtr, ctxPtr->end-3); // finish referencing dictionary content - // Note : need to handle risk of index overflow - // Use only one memory segment for dict, so any previous External Dict is lost at this stage - ctxPtr->lowLimit = ctxPtr->dictLimit; - ctxPtr->dictLimit = (U32)(ctxPtr->end - ctxPtr->base); - ctxPtr->dictBase = ctxPtr->base; - ctxPtr->base = newBlock - ctxPtr->dictLimit; - ctxPtr->end = newBlock; - ctxPtr->nextToUpdate = ctxPtr->dictLimit; // reference table must skip to from beginning of block -} - - FORCE_INLINE int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, // Index table will be updated const BYTE* ip, const BYTE* const iLimit, const BYTE** matchpos, @@ -618,8 +618,6 @@ static int LZ4HC_compress_generic ( if (compressionLevel > MAX_COMPRESSION_LEVEL) compressionLevel = MAX_COMPRESSION_LEVEL; if (compressionLevel == 0) compressionLevel = LZ4HC_DEFAULT_COMPRESSIONLEVEL; maxNbAttempts = 1 << compressionLevel; - /* check if blocks follow each other */ - if (ip != ctx->end) LZ4HC_setExternalDict(ctx, ip); ctx->end += inputSize; ip++; @@ -866,16 +864,46 @@ int LZ4_loadDictHC (LZ4_streamHC_t* LZ4_streamHCPtr, const char* dictionary, int /* compression */ +static int LZ4_compressHC_continue_generic (LZ4HC_Data_Structure* dsPtr, + const char* source, char* dest, + int inputSize, int maxOutputSize, limitedOutput_directive limit) +{ + /* auto-init if forgotten */ + if (dsPtr->base == NULL) + LZ4HC_init (dsPtr, (const BYTE*) source); + + /* check if blocks follow each other */ + if ((const BYTE*)source != dsPtr->end) LZ4HC_setExternalDict(dsPtr, (const BYTE*)source); + + /* Check overlapping input/dictionary space */ + { + const BYTE* sourceEnd = (const BYTE*) source + inputSize; + const BYTE* dictBegin = dsPtr->dictBase + dsPtr->lowLimit; + const BYTE* dictEnd = dsPtr->dictBase + dsPtr->dictLimit; + if ((sourceEnd > dictBegin) && (sourceEnd < dictEnd)) + { + dsPtr->lowLimit = (U32)(sourceEnd - dsPtr->dictBase); + if (dsPtr->dictLimit - dsPtr->lowLimit < 4) dsPtr->lowLimit = dsPtr->dictLimit; + } + } + + return LZ4HC_compress_generic (dsPtr, source, dest, inputSize, maxOutputSize, dsPtr->compressionLevel, limit); +} + int LZ4_compressHC_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize) { - if (((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->base == NULL) LZ4HC_init ((LZ4HC_Data_Structure*) LZ4_streamHCPtr, (const BYTE*) source); - return LZ4HC_compress_generic (LZ4_streamHCPtr, source, dest, inputSize, 0, ((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->compressionLevel, noLimit); + //if (((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->base == NULL) + // LZ4HC_init ((LZ4HC_Data_Structure*) LZ4_streamHCPtr, (const BYTE*) source); + //return LZ4HC_compress_generic (LZ4_streamHCPtr, source, dest, inputSize, 0, ((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->compressionLevel, noLimit); + return LZ4_compressHC_continue_generic ((LZ4HC_Data_Structure*)LZ4_streamHCPtr, source, dest, inputSize, 0, noLimit); } int LZ4_compressHC_limitedOutput_continue (LZ4_streamHC_t* LZ4_streamHCPtr, const char* source, char* dest, int inputSize, int maxOutputSize) { - if (((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->base == NULL) LZ4HC_init ((LZ4HC_Data_Structure*) LZ4_streamHCPtr, (const BYTE*) source); - return LZ4HC_compress_generic (LZ4_streamHCPtr, source, dest, inputSize, maxOutputSize, ((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->compressionLevel, limitedOutput); + //if (((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->base == NULL) + // LZ4HC_init ((LZ4HC_Data_Structure*) LZ4_streamHCPtr, (const BYTE*) source); + //return LZ4HC_compress_generic (LZ4_streamHCPtr, source, dest, inputSize, maxOutputSize, ((LZ4HC_Data_Structure*)LZ4_streamHCPtr)->compressionLevel, limitedOutput); + return LZ4_compressHC_continue_generic ((LZ4HC_Data_Structure*)LZ4_streamHCPtr, source, dest, inputSize, maxOutputSize, limitedOutput); } |