diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lz4.c | 53 |
1 files changed, 36 insertions, 17 deletions
@@ -1713,26 +1713,17 @@ int LZ4_decompress_fast_withPrefix64k(const char* source, char* dest, int origin LZ4_FORCE_O2_GCC_PPC64LE static int LZ4_decompress_safe_withSmallPrefix(const char* source, char* dest, int compressedSize, int maxOutputSize, - size_t dictSize) + size_t prefixSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, full, 0, noDict, - (BYTE*)dest-dictSize, NULL, 0); -} - -LZ4_FORCE_INLINE -int LZ4_decompress_safe_withPrefix(const char* source, char* dest, int compressedSize, int maxOutputSize, - size_t dictSize) -{ - if (dictSize >= 64 KB - 1) - return LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize); - return LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize, dictSize); + (BYTE*)dest-prefixSize, NULL, 0); } LZ4_FORCE_O2_GCC_PPC64LE /* Exported under another name, for tests/fullbench.c */ #define LZ4_decompress_safe_extDict LZ4_decompress_safe_forceExtDict int LZ4_decompress_safe_extDict(const char* source, char* dest, int compressedSize, int maxOutputSize, - const char* dictStart, size_t dictSize) + const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, endOnInputSize, full, 0, usingExtDict, @@ -1741,13 +1732,26 @@ int LZ4_decompress_safe_extDict(const char* source, char* dest, int compressedSi LZ4_FORCE_O2_GCC_PPC64LE static int LZ4_decompress_fast_extDict(const char* source, char* dest, int originalSize, - const char* dictStart, size_t dictSize) + const void* dictStart, size_t dictSize) { return LZ4_decompress_generic(source, dest, 0, originalSize, endOnOutputSize, full, 0, usingExtDict, (BYTE*)dest, (const BYTE*)dictStart, dictSize); } +/* The "double dictionary" mode, for use with e.g. ring buffers: the first part + * of the dictionary is passed as prefix, and the second via dictStart + dictSize. + * These routines are used only once, in LZ4_decompress_*_continue(). + */ +LZ4_FORCE_INLINE +int LZ4_decompress_safe_doubleDict(const char* source, char* dest, int compressedSize, int maxOutputSize, + size_t prefixSize, const void* dictStart, size_t dictSize) +{ + return LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize, + endOnInputSize, full, 0, usingExtDict, + (BYTE*)dest-prefixSize, (const BYTE*)dictStart, dictSize); +} + /*===== streaming decompression functions =====*/ LZ4_streamDecode_t* LZ4_createStreamDecode(void) @@ -1787,26 +1791,38 @@ int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dicti If it's not possible, save the relevant part of decoded data into a safe buffer, and indicate where it stands using LZ4_setStreamDecode() */ +LZ4_FORCE_O2_GCC_PPC64LE int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize) { LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse; int result; if (lz4sd->prefixSize == 0) { + /* The first call, no dictionary yet. */ + assert(lz4sd->extDictSize == 0); result = LZ4_decompress_safe(source, dest, compressedSize, maxOutputSize); if (result <= 0) return result; lz4sd->prefixSize = result; lz4sd->prefixEnd = (BYTE*)dest + result; } else if (lz4sd->prefixEnd == (BYTE*)dest) { - result = LZ4_decompress_safe_withPrefix(source, dest, compressedSize, maxOutputSize, lz4sd->prefixSize); + /* They're rolling the current segment. */ + if (lz4sd->prefixSize >= 64 KB - 1) + result = LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize); + else if (lz4sd->extDictSize == 0) + result = LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize, + lz4sd->prefixSize); + else + result = LZ4_decompress_safe_doubleDict(source, dest, compressedSize, maxOutputSize, + lz4sd->prefixSize, lz4sd->externalDict, lz4sd->extDictSize); if (result <= 0) return result; lz4sd->prefixSize += result; lz4sd->prefixEnd += result; } else { + /* The buffer wraps around, or they're switching to another buffer. */ lz4sd->extDictSize = lz4sd->prefixSize; lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize; result = LZ4_decompress_safe_extDict(source, dest, compressedSize, maxOutputSize, - (const char*)lz4sd->externalDict, lz4sd->extDictSize); + lz4sd->externalDict, lz4sd->extDictSize); if (result <= 0) return result; lz4sd->prefixSize = result; lz4sd->prefixEnd = (BYTE*)dest + result; @@ -1850,8 +1866,11 @@ int LZ4_decompress_safe_usingDict(const char* source, char* dest, int compressed { if (dictSize==0) return LZ4_decompress_safe(source, dest, compressedSize, maxOutputSize); - if (dictStart+dictSize == dest) - return LZ4_decompress_safe_withPrefix(source, dest, compressedSize, maxOutputSize, dictSize); + if (dictStart+dictSize == dest) { + if (dictSize >= 64 KB - 1) + return LZ4_decompress_safe_withPrefix64k(source, dest, compressedSize, maxOutputSize); + return LZ4_decompress_safe_withSmallPrefix(source, dest, compressedSize, maxOutputSize, dictSize); + } return LZ4_decompress_safe_extDict(source, dest, compressedSize, maxOutputSize, dictStart, dictSize); } |