lz4 0.2.1 → 0.2.2
raw patch · 5 files changed
+1782/−1709 lines, 5 filesPVP ok
version bump matches the API change (PVP)
API changes (from Hackage documentation)
Files
- lz4.cabal +1/−1
- src/cbits/lz4.c +874/−860
- src/cbits/lz4.h +128/−117
- src/cbits/lz4hc.c +719/−671
- src/cbits/lz4hc.h +60/−60
lz4.cabal view
@@ -1,5 +1,5 @@ name: lz4-version: 0.2.1+version: 0.2.2 synopsis: LZ4 compression for ByteStrings description: High level bindings to the LZ4 compression library.
src/cbits/lz4.c view
@@ -1,860 +1,874 @@-/*- LZ4 - Fast LZ compression algorithm- Copyright (C) 2011-2012, Yann Collet.- BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)-- Redistribution and use in source and binary forms, with or without- modification, are permitted provided that the following conditions are- met:-- * Redistributions of source code must retain the above copyright- notice, this list of conditions and the following disclaimer.- * Redistributions in binary form must reproduce the above- copyright notice, this list of conditions and the following disclaimer- in the documentation and/or other materials provided with the- distribution.-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.-- You can contact the author at :- - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html- - LZ4 source repository : http://code.google.com/p/lz4/-*/--//**************************************-// Tuning parameters-//**************************************-// MEMORY_USAGE :-// Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)-// Increasing memory usage improves compression ratio-// Reduced memory usage can improve speed, due to cache effect-// Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache-#define MEMORY_USAGE 14--// NOTCOMPRESSIBLE_DETECTIONLEVEL :-// Decreasing this value will make the algorithm skip faster data segments considered "incompressible"-// This may decrease compression ratio dramatically, but will be faster on incompressible data-// Increasing this value will make the algorithm search more before declaring a segment "incompressible"-// This could improve compression a bit, but will be slower on incompressible data-// The default value (6) is recommended-#define NOTCOMPRESSIBLE_DETECTIONLEVEL 6--// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :-// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU.-// You can set this option to 1 in situations where data will remain within closed environment-// This option is useless on Little_Endian CPU (such as x86)-//#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1----//**************************************-// CPU Feature Detection-//**************************************-// 32 or 64 bits ?-#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode-# define LZ4_ARCH64 1-#else-# define LZ4_ARCH64 0-#endif--// Little Endian or Big Endian ?-// Note : overwrite the below #define if you know your architecture endianess-#if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )-# define LZ4_BIG_ENDIAN 1-#else-// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.-#endif--// Unaligned memory access is automatically enabled for "common" CPU, such as x86.-// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected-// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance-#if defined(__ARM_FEATURE_UNALIGNED)-# define LZ4_FORCE_UNALIGNED_ACCESS 1-#endif--// Define this parameter if your target system or compiler does not support hardware bit count-#if defined(_MSC_VER) && defined(_WIN32_WCE) // Visual Studio for Windows CE does not support Hardware bit count-# define LZ4_FORCE_SW_BITCOUNT-#endif---//**************************************-// Compiler Options-//**************************************-#if __STDC_VERSION__ >= 199901L // C99-/* "restrict" is a known keyword */-#else-# define restrict // Disable restrict-#endif--#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)--#ifdef _MSC_VER // Visual Studio-# define inline __forceinline // Visual is not C99, but supports some kind of inline-# include <intrin.h> // For Visual 2005-# if LZ4_ARCH64 // 64-bit-# pragma intrinsic(_BitScanForward64) // For Visual 2005-# pragma intrinsic(_BitScanReverse64) // For Visual 2005-# else-# pragma intrinsic(_BitScanForward) // For Visual 2005-# pragma intrinsic(_BitScanReverse) // For Visual 2005-# endif-#endif--#ifdef _MSC_VER-# define lz4_bswap16(x) _byteswap_ushort(x)-#else-# define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))-#endif--#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)-# define expect(expr,value) (__builtin_expect ((expr),(value)) )-#else-# define expect(expr,value) (expr)-#endif--#define likely(expr) expect((expr) != 0, 1)-#define unlikely(expr) expect((expr) != 0, 0)---//**************************************-// Includes-//**************************************-#include <stdlib.h> // for malloc-#include <string.h> // for memset-#include "lz4.h"---//**************************************-// Basic Types-//**************************************-#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively-# define BYTE unsigned __int8-# define U16 unsigned __int16-# define U32 unsigned __int32-# define S32 __int32-# define U64 unsigned __int64-#else-# include <stdint.h>-# define BYTE uint8_t-# define U16 uint16_t-# define U32 uint32_t-# define S32 int32_t-# define U64 uint64_t-#endif--#ifndef LZ4_FORCE_UNALIGNED_ACCESS-# pragma pack(push, 1)-#endif--typedef struct _U16_S { U16 v; } U16_S;-typedef struct _U32_S { U32 v; } U32_S;-typedef struct _U64_S { U64 v; } U64_S;--#ifndef LZ4_FORCE_UNALIGNED_ACCESS-# pragma pack(pop)-#endif--#define A64(x) (((U64_S *)(x))->v)-#define A32(x) (((U32_S *)(x))->v)-#define A16(x) (((U16_S *)(x))->v)---//**************************************-// Constants-//**************************************-#define MINMATCH 4--#define HASH_LOG (MEMORY_USAGE-2)-#define HASHTABLESIZE (1 << HASH_LOG)-#define HASH_MASK (HASHTABLESIZE - 1)--#define SKIPSTRENGTH (NOTCOMPRESSIBLE_DETECTIONLEVEL>2?NOTCOMPRESSIBLE_DETECTIONLEVEL:2)-#define STACKLIMIT 13-#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).-#define COPYLENGTH 8-#define LASTLITERALS 5-#define MFLIMIT (COPYLENGTH+MINMATCH)-#define MINLENGTH (MFLIMIT+1)--#define MAXD_LOG 16-#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)--#define ML_BITS 4-#define ML_MASK ((1U<<ML_BITS)-1)-#define RUN_BITS (8-ML_BITS)-#define RUN_MASK ((1U<<RUN_BITS)-1)---//**************************************-// Architecture-specific macros-//**************************************-#if LZ4_ARCH64 // 64-bit-# define STEPSIZE 8-# define UARCH U64-# define AARCH A64-# define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8;-# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d)-# define LZ4_SECURECOPY(s,d,e) if (d<e) LZ4_WILDCOPY(s,d,e)-# define HTYPE U32-# define INITBASE(base) const BYTE* const base = ip-#else // 32-bit-# define STEPSIZE 4-# define UARCH U32-# define AARCH A32-# define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4;-# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);-# define LZ4_SECURECOPY LZ4_WILDCOPY-# define HTYPE const BYTE*-# define INITBASE(base) const int base = 0-#endif--#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))-# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }-# define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }-#else // Little Endian-# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }-# define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }-#endif---//**************************************-// Local structures-//**************************************-struct refTables-{- HTYPE hashTable[HASHTABLESIZE];-};---//**************************************-// Macros-//**************************************-#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))-#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))-#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);-#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; }---//****************************-// Private functions-//****************************-#if LZ4_ARCH64--static inline int LZ4_NbCommonBytes (register U64 val)-{-#if defined(LZ4_BIG_ENDIAN)- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanReverse64( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_clzll(val) >> 3);- #else- int r;- if (!(val>>32)) { r=4; } else { r=0; val>>=32; }- if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }- r += (!val);- return r;- #endif-#else- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanForward64( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_ctzll(val) >> 3);- #else- static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };- return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];- #endif-#endif-}--#else--static inline int LZ4_NbCommonBytes (register U32 val)-{-#if defined(LZ4_BIG_ENDIAN)- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanReverse( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_clz(val) >> 3);- #else- int r;- if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }- r += (!val);- return r;- #endif-#else- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanForward( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_ctz(val) >> 3);- #else- static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };- return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];- #endif-#endif-}--#endif----//******************************-// Compression functions-//******************************--// LZ4_compressCtx :-// ------------------// Compress 'isize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.-// If it cannot achieve it, compression will stop, and result of the function will be zero.-// return : the number of bytes written in buffer 'dest', or 0 if the compression fails--static inline int LZ4_compressCtx(void** ctx,- const char* source,- char* dest,- int isize,- int maxOutputSize)-{-#if HEAPMODE- struct refTables *srt = (struct refTables *) (*ctx);- HTYPE* HashTable;-#else- HTYPE HashTable[HASHTABLESIZE] = {0};-#endif-- const BYTE* ip = (BYTE*) source;- INITBASE(base);- const BYTE* anchor = ip;- const BYTE* const iend = ip + isize;- const BYTE* const mflimit = iend - MFLIMIT;-#define matchlimit (iend - LASTLITERALS)-- BYTE* op = (BYTE*) dest;- BYTE* const oend = op + maxOutputSize;-- int len, length;- const int skipStrength = SKIPSTRENGTH;- U32 forwardH;--- // Init- if (isize<MINLENGTH) goto _last_literals;-#if HEAPMODE- if (*ctx == NULL)- {- srt = (struct refTables *) malloc ( sizeof(struct refTables) );- *ctx = (void*) srt;- }- HashTable = (HTYPE*)(srt->hashTable);- memset((void*)HashTable, 0, sizeof(srt->hashTable));-#else- (void) ctx;-#endif--- // First Byte- HashTable[LZ4_HASH_VALUE(ip)] = ip - base;- ip++; forwardH = LZ4_HASH_VALUE(ip);-- // Main Loop- for ( ; ; )- {- int findMatchAttempts = (1U << skipStrength) + 3;- const BYTE* forwardIp = ip;- const BYTE* ref;- BYTE* token;-- // Find a match- do {- U32 h = forwardH;- int step = findMatchAttempts++ >> skipStrength;- ip = forwardIp;- forwardIp = ip + step;-- if unlikely(forwardIp > mflimit) { goto _last_literals; }-- forwardH = LZ4_HASH_VALUE(forwardIp);- ref = base + HashTable[h];- HashTable[h] = ip - base;-- } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));-- // Catch up- while ((ip>anchor) && (ref>(BYTE*)source) && unlikely(ip[-1]==ref[-1])) { ip--; ref--; }-- // Encode Literal length- length = (int)(ip - anchor);- token = op++;- if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) >= oend) return 0; // Check output limit-#ifdef _MSC_VER- if (length>=(int)RUN_MASK) - { - int len = length-RUN_MASK; - *token=(RUN_MASK<<ML_BITS); - if (len>254)- {- do { *op++ = 255; len -= 255; } while (len>254);- *op++ = (BYTE)len; - memcpy(op, anchor, length);- op += length;- goto _next_match;- }- else- *op++ = (BYTE)len; - }- else *token = (length<<ML_BITS);-#else- if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }- else *token = (length<<ML_BITS);-#endif-- // Copy Literals- LZ4_BLINDCOPY(anchor, op, length);--_next_match:- // Encode Offset- LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref));-- // Start Counting- ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified- anchor = ip;- while likely(ip<matchlimit-(STEPSIZE-1))- {- UARCH diff = AARCH(ref) ^ AARCH(ip);- if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }- ip += LZ4_NbCommonBytes(diff);- goto _endCount;- }- if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }- if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }- if ((ip<matchlimit) && (*ref == *ip)) ip++;-_endCount:-- // Encode MatchLength- len = (int)(ip - anchor);- if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }- else *token += len;-- // Test end of chunk- if (ip > mflimit) { anchor = ip; break; }-- // Fill table- HashTable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;-- // Test next position- ref = base + HashTable[LZ4_HASH_VALUE(ip)];- HashTable[LZ4_HASH_VALUE(ip)] = ip - base;- if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }-- // Prepare next loop- anchor = ip++;- forwardH = LZ4_HASH_VALUE(ip);- }--_last_literals:- // Encode Last Literals- {- int lastRun = (int)(iend - anchor);- if (((char*)op - dest) + lastRun + 1 + ((lastRun-15)/255) >= maxOutputSize) return 0;- if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }- else *op++ = (lastRun<<ML_BITS);- memcpy(op, anchor, iend - anchor);- op += iend-anchor;- }-- // End- return (int) (((char*)op)-dest);-}----// Note : this function is valid only if isize < LZ4_64KLIMIT-#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1))-#define HASHLOG64K (HASH_LOG+1)-#define HASH64KTABLESIZE (1U<<HASHLOG64K)-#define LZ4_HASH64K_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG64K))-#define LZ4_HASH64K_VALUE(p) LZ4_HASH64K_FUNCTION(A32(p))-static inline int LZ4_compress64kCtx(void** ctx,- const char* source,- char* dest,- int isize,- int maxOutputSize)-{-#if HEAPMODE- struct refTables *srt = (struct refTables *) (*ctx);- U16* HashTable;-#else- U16 HashTable[HASH64KTABLESIZE] = {0};-#endif-- const BYTE* ip = (BYTE*) source;- const BYTE* anchor = ip;- const BYTE* const base = ip;- const BYTE* const iend = ip + isize;- const BYTE* const mflimit = iend - MFLIMIT;-#define matchlimit (iend - LASTLITERALS)-- BYTE* op = (BYTE*) dest;- BYTE* const oend = op + maxOutputSize;-- int len, length;- const int skipStrength = SKIPSTRENGTH;- U32 forwardH;--- // Init- if (isize<MINLENGTH) goto _last_literals;-#if HEAPMODE- if (*ctx == NULL)- {- srt = (struct refTables *) malloc ( sizeof(struct refTables) );- *ctx = (void*) srt;- }- HashTable = (U16*)(srt->hashTable);- memset((void*)HashTable, 0, sizeof(srt->hashTable));-#else- (void) ctx;-#endif--- // First Byte- ip++; forwardH = LZ4_HASH64K_VALUE(ip);-- // Main Loop- for ( ; ; )- {- int findMatchAttempts = (1U << skipStrength) + 3;- const BYTE* forwardIp = ip;- const BYTE* ref;- BYTE* token;-- // Find a match- do {- U32 h = forwardH;- int step = findMatchAttempts++ >> skipStrength;- ip = forwardIp;- forwardIp = ip + step;-- if (forwardIp > mflimit) { goto _last_literals; }-- forwardH = LZ4_HASH64K_VALUE(forwardIp);- ref = base + HashTable[h];- HashTable[h] = (U16)(ip - base);-- } while (A32(ref) != A32(ip));-- // Catch up- while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }-- // Encode Literal length- length = (int)(ip - anchor);- token = op++;- if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) >= oend) return 0; // Check output limit-#ifdef _MSC_VER- if (length>=(int)RUN_MASK) - { - int len = length-RUN_MASK; - *token=(RUN_MASK<<ML_BITS); - if (len>254)- {- do { *op++ = 255; len -= 255; } while (len>254);- *op++ = (BYTE)len; - memcpy(op, anchor, length);- op += length;- goto _next_match;- }- else- *op++ = (BYTE)len; - }- else *token = (length<<ML_BITS);-#else- if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }- else *token = (length<<ML_BITS);-#endif-- // Copy Literals- LZ4_BLINDCOPY(anchor, op, length);--_next_match:- // Encode Offset- LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref));-- // Start Counting- ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified- anchor = ip;- while (ip<matchlimit-(STEPSIZE-1))- {- UARCH diff = AARCH(ref) ^ AARCH(ip);- if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; }- ip += LZ4_NbCommonBytes(diff);- goto _endCount;- }- if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; }- if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }- if ((ip<matchlimit) && (*ref == *ip)) ip++;-_endCount:-- // Encode MatchLength- len = (int)(ip - anchor);- if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }- else *token += len;-- // Test end of chunk- if (ip > mflimit) { anchor = ip; break; }-- // Fill table- HashTable[LZ4_HASH64K_VALUE(ip-2)] = (U16)(ip - 2 - base);-- // Test next position- ref = base + HashTable[LZ4_HASH64K_VALUE(ip)];- HashTable[LZ4_HASH64K_VALUE(ip)] = (U16)(ip - base);- if (A32(ref) == A32(ip)) { token = op++; *token=0; goto _next_match; }-- // Prepare next loop- anchor = ip++;- forwardH = LZ4_HASH64K_VALUE(ip);- }--_last_literals:- // Encode Last Literals- {- int lastRun = (int)(iend - anchor);- if (((char*)op - dest) + lastRun + 1 + ((lastRun)>>8) >= maxOutputSize) return 0;- if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }- else *op++ = (lastRun<<ML_BITS);- memcpy(op, anchor, iend - anchor);- op += iend-anchor;- }-- // End- return (int) (((char*)op)-dest);-}---int LZ4_compress_limitedOutput(const char* source, - char* dest, - int isize, - int maxOutputSize)-{-#if HEAPMODE- void* ctx = malloc(sizeof(struct refTables));- int result;- if (isize < LZ4_64KLIMIT)- result = LZ4_compress64kCtx(&ctx, source, dest, isize, maxOutputSize);- else result = LZ4_compressCtx(&ctx, source, dest, isize, maxOutputSize);- free(ctx);- return result;-#else- if (isize < (int)LZ4_64KLIMIT) return LZ4_compress64kCtx(NULL, source, dest, isize, maxOutputSize);- return LZ4_compressCtx(NULL, source, dest, isize, maxOutputSize);-#endif-}---int LZ4_compress(const char* source,- char* dest,- int isize)-{- return LZ4_compress_limitedOutput(source, dest, isize, LZ4_compressBound(isize));-}-----//****************************-// Decompression functions-//****************************--// Note : The decoding functions LZ4_uncompress() and LZ4_uncompress_unknownOutputSize()-// are safe against "buffer overflow" attack type.-// They will never write nor read outside of the provided output buffers.-// LZ4_uncompress_unknownOutputSize() also insures that it will never read outside of the input buffer.-// A corrupted input will produce an error result, a negative int, indicating the position of the error within input stream.--int LZ4_uncompress(const char* source,- char* dest,- int osize)-{- // Local Variables- const BYTE* restrict ip = (const BYTE*) source;- const BYTE* restrict ref;-- BYTE* restrict op = (BYTE*) dest;- BYTE* const oend = op + osize;- BYTE* cpy;-- BYTE token;-- int len, length;- size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};--- // Main Loop- while (1)- {- // get runlength- token = *ip++;- if ((length=(token>>ML_BITS)) == RUN_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }-- // copy literals- cpy = op+length;- if unlikely(cpy>oend-COPYLENGTH)- {- if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer- memcpy(op, ip, length);- ip += length;- break; // Necessarily EOF- }- LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;-- // get offset- LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;- if (ref < (BYTE* const)dest) goto _output_error; // Error : offset create reference outside destination buffer-- // get matchlength- if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }-- // copy repeated sequence- if unlikely(op-ref<STEPSIZE)- {-#if LZ4_ARCH64- size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};- size_t dec2 = dec2table[op-ref];-#else- const int dec2 = 0;-#endif- *op++ = *ref++;- *op++ = *ref++;- *op++ = *ref++;- *op++ = *ref++;- ref -= dec[op-ref];- A32(op)=A32(ref); op += STEPSIZE-4;- ref -= dec2;- } else { LZ4_COPYSTEP(ref,op); }- cpy = op + length - (STEPSIZE-4);- if (cpy>oend-COPYLENGTH)- {- if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer- LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));- while(op<cpy) *op++=*ref++;- op=cpy;- if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)- continue;- }- LZ4_SECURECOPY(ref, op, cpy);- op=cpy; // correction- }-- // end of decoding- return (int) (((char*)ip)-source);-- // write overflow error detected-_output_error:- return (int) (-(((char*)ip)-source));-}---int LZ4_uncompress_unknownOutputSize(- const char* source,- char* dest,- int isize,- int maxOutputSize)-{- // Local Variables- const BYTE* restrict ip = (const BYTE*) source;- const BYTE* const iend = ip + isize;- const BYTE* restrict ref;-- BYTE* restrict op = (BYTE*) dest;- BYTE* const oend = op + maxOutputSize;- BYTE* cpy;-- size_t dec[] ={0, 3, 2, 3, 0, 0, 0, 0};--- // Main Loop- while (ip<iend)- {- BYTE token;- int length;-- // get runlength- token = *ip++;- if ((length=(token>>ML_BITS)) == RUN_MASK) { int s=255; while ((ip<iend) && (s==255)) { s=*ip++; length += s; } }-- // copy literals- cpy = op+length;- if ((cpy>oend-COPYLENGTH) || (ip+length>iend-COPYLENGTH))- {- if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer- if (ip+length > iend) goto _output_error; // Error : request to read beyond source buffer- memcpy(op, ip, length);- op += length;- ip += length;- if (ip<iend) goto _output_error; // Error : LZ4 format violation- break; // Necessarily EOF, due to parsing restrictions- }- LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;-- // get offset- LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;- if (ref < (BYTE* const)dest) goto _output_error; // Error : offset creates reference outside of destination buffer-- // get matchlength- if ((length=(token&ML_MASK)) == ML_MASK) { while (ip<iend) { int s = *ip++; length +=s; if (s==255) continue; break; } }-- // copy repeated sequence- if unlikely(op-ref<STEPSIZE)- {-#if LZ4_ARCH64- size_t dec2table[]={0, 0, 0, -1, 0, 1, 2, 3};- size_t dec2 = dec2table[op-ref];-#else- const int dec2 = 0;-#endif- *op++ = *ref++;- *op++ = *ref++;- *op++ = *ref++;- *op++ = *ref++;- ref -= dec[op-ref];- A32(op)=A32(ref); op += STEPSIZE-4;- ref -= dec2;- } else { LZ4_COPYSTEP(ref,op); }- cpy = op + length - (STEPSIZE-4);- if (cpy>oend-COPYLENGTH)- {- if (cpy > oend) goto _output_error; // Error : request to write outside of destination buffer- LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));- while(op<cpy) *op++=*ref++;- op=cpy;- if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)- continue;- }- LZ4_SECURECOPY(ref, op, cpy);- op=cpy; // correction- }-- // end of decoding- return (int) (((char*)op)-dest);-- // write overflow error detected-_output_error:- return (int) (-(((char*)ip)-source));-}+/* + LZ4 - Fast LZ compression algorithm + Copyright (C) 2011-2012, Yann Collet. + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html + - LZ4 source repository : http://code.google.com/p/lz4/ +*/ + +//************************************** +// Tuning parameters +//************************************** +// MEMORY_USAGE : +// Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.) +// Increasing memory usage improves compression ratio +// Reduced memory usage can improve speed, due to cache effect +// Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache +#define MEMORY_USAGE 14 + +// NOTCOMPRESSIBLE_DETECTIONLEVEL : +// Decreasing this value will make the algorithm skip faster data segments considered "incompressible" +// This may decrease compression ratio dramatically, but will be faster on incompressible data +// Increasing this value will make the algorithm search more before declaring a segment "incompressible" +// This could improve compression a bit, but will be slower on incompressible data +// The default value (6) is recommended +#define NOTCOMPRESSIBLE_DETECTIONLEVEL 6 + +// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE : +// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU. +// You can set this option to 1 in situations where data will remain within closed environment +// This option is useless on Little_Endian CPU (such as x86) +//#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1 + + + +//************************************** +// CPU Feature Detection +//************************************** +// 32 or 64 bits ? +#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode +# define LZ4_ARCH64 1 +#else +# define LZ4_ARCH64 0 +#endif + +// Little Endian or Big Endian ? +// Overwrite the #define below if you know your architecture endianess +#if defined (__GLIBC__) +# include <endian.h> +# if (__BYTE_ORDER == __BIG_ENDIAN) +# define LZ4_BIG_ENDIAN 1 +# endif +#elif (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN)) +# define LZ4_BIG_ENDIAN 1 +#elif defined(__sparc) || defined(__sparc__) \ + || defined(__ppc__) || defined(_POWER) || defined(__powerpc__) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) \ + || defined(__hpux) || defined(__hppa) \ + || defined(_MIPSEB) || defined(__s390__) +# define LZ4_BIG_ENDIAN 1 +#else +// Little Endian assumed. PDP Endian and other very rare endian format are unsupported. +#endif + +// Unaligned memory access is automatically enabled for "common" CPU, such as x86. +// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected +// If you know your target CPU supports unaligned memory access, you want to force this option manually to improve performance +#if defined(__ARM_FEATURE_UNALIGNED) +# define LZ4_FORCE_UNALIGNED_ACCESS 1 +#endif + +// Define this parameter if your target system or compiler does not support hardware bit count +#if defined(_MSC_VER) && defined(_WIN32_WCE) // Visual Studio for Windows CE does not support Hardware bit count +# define LZ4_FORCE_SW_BITCOUNT +#endif + + +//************************************** +// Compiler Options +//************************************** +#if __STDC_VERSION__ >= 199901L // C99 +/* "restrict" is a known keyword */ +#else +# define restrict // Disable restrict +#endif + +#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) + +#ifdef _MSC_VER // Visual Studio +# include <intrin.h> // For Visual 2005 +# if LZ4_ARCH64 // 64-bit +# pragma intrinsic(_BitScanForward64) // For Visual 2005 +# pragma intrinsic(_BitScanReverse64) // For Visual 2005 +# else +# pragma intrinsic(_BitScanForward) // For Visual 2005 +# pragma intrinsic(_BitScanReverse) // For Visual 2005 +# endif +#endif + +#ifdef _MSC_VER +# define lz4_bswap16(x) _byteswap_ushort(x) +#else +# define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))) +#endif + +#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__) +# define expect(expr,value) (__builtin_expect ((expr),(value)) ) +#else +# define expect(expr,value) (expr) +#endif + +#define likely(expr) expect((expr) != 0, 1) +#define unlikely(expr) expect((expr) != 0, 0) + + +//************************************** +// Includes +//************************************** +#include <stdlib.h> // for malloc +#include <string.h> // for memset +#include "lz4.h" + + +//************************************** +// Basic Types +//************************************** +#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively +# define BYTE unsigned __int8 +# define U16 unsigned __int16 +# define U32 unsigned __int32 +# define S32 __int32 +# define U64 unsigned __int64 +#else +# include <stdint.h> +# define BYTE uint8_t +# define U16 uint16_t +# define U32 uint32_t +# define S32 int32_t +# define U64 uint64_t +#endif + +#ifndef LZ4_FORCE_UNALIGNED_ACCESS +# pragma pack(push, 1) +#endif + +typedef struct _U16_S { U16 v; } U16_S; +typedef struct _U32_S { U32 v; } U32_S; +typedef struct _U64_S { U64 v; } U64_S; + +#ifndef LZ4_FORCE_UNALIGNED_ACCESS +# pragma pack(pop) +#endif + +#define A64(x) (((U64_S *)(x))->v) +#define A32(x) (((U32_S *)(x))->v) +#define A16(x) (((U16_S *)(x))->v) + + +//************************************** +// Constants +//************************************** +#define MINMATCH 4 + +#define HASH_LOG (MEMORY_USAGE-2) +#define HASHTABLESIZE (1 << HASH_LOG) +#define HASH_MASK (HASHTABLESIZE - 1) + +#define SKIPSTRENGTH (NOTCOMPRESSIBLE_DETECTIONLEVEL>2?NOTCOMPRESSIBLE_DETECTIONLEVEL:2) +#define STACKLIMIT 13 +#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()). +#define COPYLENGTH 8 +#define LASTLITERALS 5 +#define MFLIMIT (COPYLENGTH+MINMATCH) +#define MINLENGTH (MFLIMIT+1) + +#define MAXD_LOG 16 +#define MAX_DISTANCE ((1 << MAXD_LOG) - 1) + +#define ML_BITS 4 +#define ML_MASK ((1U<<ML_BITS)-1) +#define RUN_BITS (8-ML_BITS) +#define RUN_MASK ((1U<<RUN_BITS)-1) + + +//************************************** +// Architecture-specific macros +//************************************** +#if LZ4_ARCH64 // 64-bit +# define STEPSIZE 8 +# define UARCH U64 +# define AARCH A64 +# define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8; +# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d) +# define LZ4_SECURECOPY(s,d,e) if (d<e) LZ4_WILDCOPY(s,d,e) +# define HTYPE U32 +# define INITBASE(base) const BYTE* const base = ip +#else // 32-bit +# define STEPSIZE 4 +# define UARCH U32 +# define AARCH A32 +# define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4; +# define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d); +# define LZ4_SECURECOPY LZ4_WILDCOPY +# define HTYPE const BYTE* +# define INITBASE(base) const int base = 0 +#endif + +#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE)) +# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; } +# define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; } +#else // Little Endian +# define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); } +# define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; } +#endif + + +//************************************** +// Local structures +//************************************** +struct refTables +{ + HTYPE hashTable[HASHTABLESIZE]; +}; + + +//************************************** +// Macros +//************************************** +#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG)) +#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p)) +#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e); +#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; } + + +//**************************** +// Private functions +//**************************** +#if LZ4_ARCH64 + +static inline int LZ4_NbCommonBytes (register U64 val) +{ +#if defined(LZ4_BIG_ENDIAN) + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanReverse64( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_clzll(val) >> 3); + #else + int r; + if (!(val>>32)) { r=4; } else { r=0; val>>=32; } + if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; } + r += (!val); + return r; + #endif +#else + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanForward64( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_ctzll(val) >> 3); + #else + static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 }; + return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58]; + #endif +#endif +} + +#else + +static inline int LZ4_NbCommonBytes (register U32 val) +{ +#if defined(LZ4_BIG_ENDIAN) + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanReverse( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_clz(val) >> 3); + #else + int r; + if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; } + r += (!val); + return r; + #endif +#else + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanForward( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_ctz(val) >> 3); + #else + static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 }; + return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27]; + #endif +#endif +} + +#endif + + + +//****************************** +// Compression functions +//****************************** + +// LZ4_compressCtx : +// ----------------- +// Compress 'isize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'. +// If it cannot achieve it, compression will stop, and result of the function will be zero. +// return : the number of bytes written in buffer 'dest', or 0 if the compression fails + +static inline int LZ4_compressCtx(void** ctx, + const char* source, + char* dest, + int isize, + int maxOutputSize) +{ +#if HEAPMODE + struct refTables *srt = (struct refTables *) (*ctx); + HTYPE* HashTable; +#else + HTYPE HashTable[HASHTABLESIZE] = {0}; +#endif + + const BYTE* ip = (BYTE*) source; + INITBASE(base); + const BYTE* anchor = ip; + const BYTE* const iend = ip + isize; + const BYTE* const mflimit = iend - MFLIMIT; +#define matchlimit (iend - LASTLITERALS) + + BYTE* op = (BYTE*) dest; + BYTE* const oend = op + maxOutputSize; + + int len, length; + const int skipStrength = SKIPSTRENGTH; + U32 forwardH; + + + // Init + if (isize<MINLENGTH) goto _last_literals; +#if HEAPMODE + if (*ctx == NULL) + { + srt = (struct refTables *) malloc ( sizeof(struct refTables) ); + *ctx = (void*) srt; + } + HashTable = (HTYPE*)(srt->hashTable); + memset((void*)HashTable, 0, sizeof(srt->hashTable)); +#else + (void) ctx; +#endif + + + // First Byte + HashTable[LZ4_HASH_VALUE(ip)] = ip - base; + ip++; forwardH = LZ4_HASH_VALUE(ip); + + // Main Loop + for ( ; ; ) + { + int findMatchAttempts = (1U << skipStrength) + 3; + const BYTE* forwardIp = ip; + const BYTE* ref; + BYTE* token; + + // Find a match + do { + U32 h = forwardH; + int step = findMatchAttempts++ >> skipStrength; + ip = forwardIp; + forwardIp = ip + step; + + if unlikely(forwardIp > mflimit) { goto _last_literals; } + + forwardH = LZ4_HASH_VALUE(forwardIp); + ref = base + HashTable[h]; + HashTable[h] = ip - base; + + } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip))); + + // Catch up + while ((ip>anchor) && (ref>(BYTE*)source) && unlikely(ip[-1]==ref[-1])) { ip--; ref--; } + + // Encode Literal length + length = (int)(ip - anchor); + token = op++; + if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit +#ifdef _MSC_VER + if (length>=(int)RUN_MASK) + { + int len = length-RUN_MASK; + *token=(RUN_MASK<<ML_BITS); + if (len>254) + { + do { *op++ = 255; len -= 255; } while (len>254); + *op++ = (BYTE)len; + memcpy(op, anchor, length); + op += length; + goto _next_match; + } + else + *op++ = (BYTE)len; + } + else *token = (length<<ML_BITS); +#else + if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; } + else *token = (length<<ML_BITS); +#endif + + // Copy Literals + LZ4_BLINDCOPY(anchor, op, length); + +_next_match: + // Encode Offset + LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref)); + + // Start Counting + ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified + anchor = ip; + while likely(ip<matchlimit-(STEPSIZE-1)) + { + UARCH diff = AARCH(ref) ^ AARCH(ip); + if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; } + ip += LZ4_NbCommonBytes(diff); + goto _endCount; + } + if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; } + if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; } + if ((ip<matchlimit) && (*ref == *ip)) ip++; +_endCount: + + // Encode MatchLength + len = (int)(ip - anchor); + if unlikely(op + (1 + LASTLITERALS) + (len>>8) > oend) return 0; // Check output limit + if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; } + else *token += len; + + // Test end of chunk + if (ip > mflimit) { anchor = ip; break; } + + // Fill table + HashTable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base; + + // Test next position + ref = base + HashTable[LZ4_HASH_VALUE(ip)]; + HashTable[LZ4_HASH_VALUE(ip)] = ip - base; + if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; } + + // Prepare next loop + anchor = ip++; + forwardH = LZ4_HASH_VALUE(ip); + } + +_last_literals: + // Encode Last Literals + { + int lastRun = (int)(iend - anchor); + if (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize) return 0; + if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; } + else *op++ = (lastRun<<ML_BITS); + memcpy(op, anchor, iend - anchor); + op += iend-anchor; + } + + // End + return (int) (((char*)op)-dest); +} + + + +// Note : this function is valid only if isize < LZ4_64KLIMIT +#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1)) +#define HASHLOG64K (HASH_LOG+1) +#define HASH64KTABLESIZE (1U<<HASHLOG64K) +#define LZ4_HASH64K_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG64K)) +#define LZ4_HASH64K_VALUE(p) LZ4_HASH64K_FUNCTION(A32(p)) +static inline int LZ4_compress64kCtx(void** ctx, + const char* source, + char* dest, + int isize, + int maxOutputSize) +{ +#if HEAPMODE + struct refTables *srt = (struct refTables *) (*ctx); + U16* HashTable; +#else + U16 HashTable[HASH64KTABLESIZE] = {0}; +#endif + + const BYTE* ip = (BYTE*) source; + const BYTE* anchor = ip; + const BYTE* const base = ip; + const BYTE* const iend = ip + isize; + const BYTE* const mflimit = iend - MFLIMIT; +#define matchlimit (iend - LASTLITERALS) + + BYTE* op = (BYTE*) dest; + BYTE* const oend = op + maxOutputSize; + + int len, length; + const int skipStrength = SKIPSTRENGTH; + U32 forwardH; + + + // Init + if (isize<MINLENGTH) goto _last_literals; +#if HEAPMODE + if (*ctx == NULL) + { + srt = (struct refTables *) malloc ( sizeof(struct refTables) ); + *ctx = (void*) srt; + } + HashTable = (U16*)(srt->hashTable); + memset((void*)HashTable, 0, sizeof(srt->hashTable)); +#else + (void) ctx; +#endif + + + // First Byte + ip++; forwardH = LZ4_HASH64K_VALUE(ip); + + // Main Loop + for ( ; ; ) + { + int findMatchAttempts = (1U << skipStrength) + 3; + const BYTE* forwardIp = ip; + const BYTE* ref; + BYTE* token; + + // Find a match + do { + U32 h = forwardH; + int step = findMatchAttempts++ >> skipStrength; + ip = forwardIp; + forwardIp = ip + step; + + if (forwardIp > mflimit) { goto _last_literals; } + + forwardH = LZ4_HASH64K_VALUE(forwardIp); + ref = base + HashTable[h]; + HashTable[h] = (U16)(ip - base); + + } while (A32(ref) != A32(ip)); + + // Catch up + while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; } + + // Encode Literal length + length = (int)(ip - anchor); + token = op++; + if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit +#ifdef _MSC_VER + if (length>=(int)RUN_MASK) + { + int len = length-RUN_MASK; + *token=(RUN_MASK<<ML_BITS); + if (len>254) + { + do { *op++ = 255; len -= 255; } while (len>254); + *op++ = (BYTE)len; + memcpy(op, anchor, length); + op += length; + goto _next_match; + } + else + *op++ = (BYTE)len; + } + else *token = (length<<ML_BITS); +#else + if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; } + else *token = (length<<ML_BITS); +#endif + + // Copy Literals + LZ4_BLINDCOPY(anchor, op, length); + +_next_match: + // Encode Offset + LZ4_WRITE_LITTLEENDIAN_16(op,(U16)(ip-ref)); + + // Start Counting + ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified + anchor = ip; + while (ip<matchlimit-(STEPSIZE-1)) + { + UARCH diff = AARCH(ref) ^ AARCH(ip); + if (!diff) { ip+=STEPSIZE; ref+=STEPSIZE; continue; } + ip += LZ4_NbCommonBytes(diff); + goto _endCount; + } + if (LZ4_ARCH64) if ((ip<(matchlimit-3)) && (A32(ref) == A32(ip))) { ip+=4; ref+=4; } + if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; } + if ((ip<matchlimit) && (*ref == *ip)) ip++; +_endCount: + + // Encode MatchLength + len = (int)(ip - anchor); + if unlikely(op + (1 + LASTLITERALS) + (len>>8) > oend) return 0; // Check output limit + if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; } + else *token += len; + + // Test end of chunk + if (ip > mflimit) { anchor = ip; break; } + + // Fill table + HashTable[LZ4_HASH64K_VALUE(ip-2)] = (U16)(ip - 2 - base); + + // Test next position + ref = base + HashTable[LZ4_HASH64K_VALUE(ip)]; + HashTable[LZ4_HASH64K_VALUE(ip)] = (U16)(ip - base); + if (A32(ref) == A32(ip)) { token = op++; *token=0; goto _next_match; } + + // Prepare next loop + anchor = ip++; + forwardH = LZ4_HASH64K_VALUE(ip); + } + +_last_literals: + // Encode Last Literals + { + int lastRun = (int)(iend - anchor); + if (op + lastRun + 1 + (lastRun-RUN_MASK+255)/255 > oend) return 0; + if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; } + else *op++ = (lastRun<<ML_BITS); + memcpy(op, anchor, iend - anchor); + op += iend-anchor; + } + + // End + return (int) (((char*)op)-dest); +} + + +int LZ4_compress_limitedOutput(const char* source, + char* dest, + int isize, + int maxOutputSize) +{ +#if HEAPMODE + void* ctx = malloc(sizeof(struct refTables)); + int result; + if (isize < LZ4_64KLIMIT) + result = LZ4_compress64kCtx(&ctx, source, dest, isize, maxOutputSize); + else result = LZ4_compressCtx(&ctx, source, dest, isize, maxOutputSize); + free(ctx); + return result; +#else + if (isize < (int)LZ4_64KLIMIT) return LZ4_compress64kCtx(NULL, source, dest, isize, maxOutputSize); + return LZ4_compressCtx(NULL, source, dest, isize, maxOutputSize); +#endif +} + + +int LZ4_compress(const char* source, + char* dest, + int isize) +{ + return LZ4_compress_limitedOutput(source, dest, isize, LZ4_compressBound(isize)); +} + + + + +//**************************** +// Decompression functions +//**************************** + +// Note : The decoding functions LZ4_uncompress() and LZ4_uncompress_unknownOutputSize() +// are safe against "buffer overflow" attack type. +// They will never write nor read outside of the provided output buffers. +// LZ4_uncompress_unknownOutputSize() also insures that it will never read outside of the input buffer. +// A corrupted input will produce an error result, a negative int, indicating the position of the error within input stream. + +int LZ4_uncompress(const char* source, + char* dest, + int osize) +{ + // Local Variables + const BYTE* restrict ip = (const BYTE*) source; + const BYTE* ref; + + BYTE* op = (BYTE*) dest; + BYTE* const oend = op + osize; + BYTE* cpy; + + unsigned token; + + size_t length; + size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; +#if LZ4_ARCH64 + size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; +#endif + + + // Main Loop + while (1) + { + // get runlength + token = *ip++; + if ((length=(token>>ML_BITS)) == RUN_MASK) { size_t len; for (;(len=*ip++)==255;length+=255){} length += len; } + + // copy literals + cpy = op+length; + if unlikely(cpy>oend-COPYLENGTH) + { + if (cpy != oend) goto _output_error; // Error : not enough place for another match (min 4) + 5 literals + memcpy(op, ip, length); + ip += length; + break; // EOF + } + LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy; + + // get offset + LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2; + if unlikely(ref < (BYTE* const)dest) goto _output_error; // Error : offset create reference outside destination buffer + + // get matchlength + if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; } + + // copy repeated sequence + if unlikely((op-ref)<STEPSIZE) + { +#if LZ4_ARCH64 + size_t dec64 = dec64table[op-ref]; +#else + const int dec64 = 0; +#endif + op[0] = ref[0]; + op[1] = ref[1]; + op[2] = ref[2]; + op[3] = ref[3]; + op += 4, ref += 4; ref -= dec32table[op-ref]; + A32(op) = A32(ref); + op += STEPSIZE-4; ref -= dec64; + } else { LZ4_COPYSTEP(ref,op); } + cpy = op + length - (STEPSIZE-4); + if (cpy>oend-COPYLENGTH) + { + if (cpy > oend) goto _output_error; // Error : request to write beyond destination buffer + LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH)); + while(op<cpy) *op++=*ref++; + op=cpy; + if (op == oend) goto _output_error; // Check EOF (should never happen, since last 5 bytes are supposed to be literals) + continue; + } + LZ4_SECURECOPY(ref, op, cpy); + op=cpy; // correction + } + + // end of decoding + return (int) (((char*)ip)-source); + + // write overflow error detected +_output_error: + return (int) (-(((char*)ip)-source)); +} + + +int LZ4_uncompress_unknownOutputSize( + const char* source, + char* dest, + int isize, + int maxOutputSize) +{ + // Local Variables + const BYTE* restrict ip = (const BYTE*) source; + const BYTE* const iend = ip + isize; + const BYTE* ref; + + BYTE* op = (BYTE*) dest; + BYTE* const oend = op + maxOutputSize; + BYTE* cpy; + + size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; +#if LZ4_ARCH64 + size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; +#endif + + + // Main Loop + while (ip<iend) + { + unsigned token; + size_t length; + + // get runlength + token = *ip++; + if ((length=(token>>ML_BITS)) == RUN_MASK) { int s=255; while ((ip<iend) && (s==255)) { s=*ip++; length += s; } } + + // copy literals + cpy = op+length; + if ((cpy>oend-COPYLENGTH) || (ip+length>iend-COPYLENGTH)) + { + if (cpy > oend) goto _output_error; // Error : writes beyond output buffer + if (ip+length != iend) goto _output_error; // Error : LZ4 format requires to consume all input at this stage + memcpy(op, ip, length); + op += length; + break; // Necessarily EOF, due to parsing restrictions + } + LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy; + + // get offset + LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2; + if (ref < (BYTE* const)dest) goto _output_error; // Error : offset creates reference outside of destination buffer + + // get matchlength + if ((length=(token&ML_MASK)) == ML_MASK) { while (ip<iend) { int s = *ip++; length +=s; if (s==255) continue; break; } } + + // copy repeated sequence + if unlikely(op-ref<STEPSIZE) + { +#if LZ4_ARCH64 + size_t dec64 = dec64table[op-ref]; +#else + const int dec64 = 0; +#endif + op[0] = ref[0]; + op[1] = ref[1]; + op[2] = ref[2]; + op[3] = ref[3]; + op += 4, ref += 4; ref -= dec32table[op-ref]; + A32(op) = A32(ref); + op += STEPSIZE-4; ref -= dec64; + } else { LZ4_COPYSTEP(ref,op); } + cpy = op + length - (STEPSIZE-4); + if (cpy>oend-COPYLENGTH) + { + if (cpy > oend) goto _output_error; // Error : request to write outside of destination buffer + LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH)); + while(op<cpy) *op++=*ref++; + op=cpy; + if (op == oend) goto _output_error; // Check EOF (should never happen, since last 5 bytes are supposed to be literals) + continue; + } + LZ4_SECURECOPY(ref, op, cpy); + op=cpy; // correction + } + + // end of decoding + return (int) (((char*)op)-dest); + + // write overflow error detected +_output_error: + return (int) (-(((char*)ip)-source)); +} +
src/cbits/lz4.h view
@@ -1,117 +1,128 @@-/*- LZ4 - Fast LZ compression algorithm- Header File- Copyright (C) 2011-2012, Yann Collet.- BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)-- Redistribution and use in source and binary forms, with or without- modification, are permitted provided that the following conditions are- met:-- * Redistributions of source code must retain the above copyright- notice, this list of conditions and the following disclaimer.- * Redistributions in binary form must reproduce the above- copyright notice, this list of conditions and the following disclaimer- in the documentation and/or other materials provided with the- distribution.-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.-- You can contact the author at :- - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html- - LZ4 source repository : http://code.google.com/p/lz4/-*/-#pragma once--#if defined (__cplusplus)-extern "C" {-#endif---//****************************-// Simple Functions-//****************************--int LZ4_compress (const char* source, char* dest, int isize);-int LZ4_uncompress (const char* source, char* dest, int osize);--/*-LZ4_compress() :- Compresses 'isize' bytes from 'source' into 'dest'.- Destination buffer must be already allocated,- and must be sized to handle worst cases situations (input data not compressible)- Worst case size evaluation is provided by macro LZ4_compressBound()-- isize : is the input size. Max supported value is ~1.9GB- return : the number of bytes written in buffer dest---LZ4_uncompress() :- osize : is the output size, therefore the original size- return : the number of bytes read in the source buffer- If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction- This function never writes beyond dest + osize, and is therefore protected against malicious data packets- note : destination buffer must be already allocated.- its size must be a minimum of 'osize' bytes.-*/---//****************************-// Advanced Functions-//****************************--#define LZ4_compressBound(isize) (isize + (isize/255) + 16)--/*-LZ4_compressBound() :- Provides the maximum size that LZ4 may output in a "worst case" scenario (input data not compressible)- primarily useful for memory allocation of output buffer.-- isize : is the input size. Max supported value is ~1.9GB- return : maximum output size in a "worst case" scenario- note : this function is limited by "int" range (2^31-1)-*/---int LZ4_compress_limitedOutput (const char* source, char* dest, int isize, int maxOutputSize);--/*-LZ4_compress_limitedOutput() :- Compress 'isize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.- If it cannot achieve it, compression will stop, and result of the function will be zero.- This function never writes outside of provided output buffer.-- isize : is the input size. Max supported value is ~1.9GB- maxOutputSize : is the size of the destination buffer (which must be already allocated)- return : the number of bytes written in buffer 'dest'- or 0 if the compression fails-*/---int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);--/*-LZ4_uncompress_unknownOutputSize() :- isize : is the input size, therefore the compressed size- maxOutputSize : is the size of the destination buffer (which must be already allocated)- return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize)- If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction- This function never writes beyond dest + maxOutputSize, and is therefore protected against malicious data packets- note : Destination buffer must be already allocated.- This version is slightly slower than LZ4_uncompress()-*/---#if defined (__cplusplus)-}-#endif+/* + LZ4 - Fast LZ compression algorithm + Header File + Copyright (C) 2011-2012, Yann Collet. + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html + - LZ4 source repository : http://code.google.com/p/lz4/ +*/ +#pragma once + +#if defined (__cplusplus) +extern "C" { +#endif + + +//************************************** +// Compiler Options +//************************************** +#if defined(_MSC_VER) && !defined(__cplusplus) // Visual Studio +# define inline __inline // Visual is not C99, but supports some kind of inline +#endif + + +//**************************** +// Simple Functions +//**************************** + +int LZ4_compress (const char* source, char* dest, int isize); +int LZ4_uncompress (const char* source, char* dest, int osize); + +/* +LZ4_compress() : + Compresses 'isize' bytes from 'source' into 'dest'. + Destination buffer must be already allocated, + and must be sized to handle worst cases situations (input data not compressible) + Worst case size evaluation is provided by function LZ4_compressBound() + + isize : is the input size. Max supported value is ~1.9GB + return : the number of bytes written in buffer dest + + +LZ4_uncompress() : + osize : is the output size, therefore the original size + return : the number of bytes read in the source buffer + If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction + This function never writes outside of provided buffers, and never modifies input buffer. + note : destination buffer must be already allocated. + its size must be a minimum of 'osize' bytes. +*/ + + +//**************************** +// Advanced Functions +//**************************** + +static inline int LZ4_compressBound(int isize) { return ((isize) + ((isize)/255) + 16); } +#define LZ4_COMPRESSBOUND( isize) ((isize) + ((isize)/255) + 16) + +/* +LZ4_compressBound() : + Provides the maximum size that LZ4 may output in a "worst case" scenario (input data not compressible) + primarily useful for memory allocation of output buffer. + inline function is recommended for the general case, + but macro is also provided when results need to be evaluated at compile time (such as table size allocation). + + isize : is the input size. Max supported value is ~1.9GB + return : maximum output size in a "worst case" scenario + note : this function is limited by "int" range (2^31-1) +*/ + + +int LZ4_compress_limitedOutput (const char* source, char* dest, int isize, int maxOutputSize); + +/* +LZ4_compress_limitedOutput() : + Compress 'isize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'. + If it cannot achieve it, compression will stop, and result of the function will be zero. + This function never writes outside of provided output buffer. + + isize : is the input size. Max supported value is ~1.9GB + maxOutputSize : is the size of the destination buffer (which must be already allocated) + return : the number of bytes written in buffer 'dest' + or 0 if the compression fails +*/ + + +int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize); + +/* +LZ4_uncompress_unknownOutputSize() : + isize : is the input size, therefore the compressed size + maxOutputSize : is the size of the destination buffer (which must be already allocated) + return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize) + If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction + This function never writes beyond dest + maxOutputSize, and is therefore protected against malicious data packets + note : Destination buffer must be already allocated. + This version is slightly slower than LZ4_uncompress() +*/ + + +#if defined (__cplusplus) +} +#endif
src/cbits/lz4hc.c view
@@ -1,671 +1,719 @@-/*- LZ4 HC - High Compression Mode of LZ4- Copyright (C) 2011-2012, Yann Collet.- BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)-- Redistribution and use in source and binary forms, with or without- modification, are permitted provided that the following conditions are- met:-- * Redistributions of source code must retain the above copyright- notice, this list of conditions and the following disclaimer.- * Redistributions in binary form must reproduce the above- copyright notice, this list of conditions and the following disclaimer- in the documentation and/or other materials provided with the- distribution.-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.-- You can contact the author at :- - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html- - LZ4 source repository : http://code.google.com/p/lz4/-*/---//**************************************-// CPU Feature Detection-//**************************************-// 32 or 64 bits ?-#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode-#define LZ4_ARCH64 1-#else-#define LZ4_ARCH64 0-#endif--// Little Endian or Big Endian ? -#if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )-#define LZ4_BIG_ENDIAN 1-#else-// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.-#endif--// Unaligned memory access is automatically enabled for "common" CPU, such as x86.-// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected-// If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance-#if defined(__ARM_FEATURE_UNALIGNED)-#define LZ4_FORCE_UNALIGNED_ACCESS 1-#endif---//**************************************-// Compiler Options-//**************************************-#if __STDC_VERSION__ >= 199901L // C99- /* "restrict" is a known keyword */-#else-#define restrict // Disable restrict-#endif--#ifdef _MSC_VER-#define inline __forceinline // Visual is not C99, but supports some kind of inline-#include <intrin.h> // For Visual 2005-# if LZ4_ARCH64 // 64-bit-# pragma intrinsic(_BitScanForward64) // For Visual 2005-# pragma intrinsic(_BitScanReverse64) // For Visual 2005-# else-# pragma intrinsic(_BitScanForward) // For Visual 2005-# pragma intrinsic(_BitScanReverse) // For Visual 2005-# endif-#endif--#ifdef _MSC_VER // Visual Studio-#define bswap16(x) _byteswap_ushort(x)-#else-#define bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))-#endif---//**************************************-// Includes-//**************************************-#include <stdlib.h> // calloc, free-#include <string.h> // memset, memcpy-#include "lz4hc.h"--#define ALLOCATOR(s) calloc(1,s)-#define FREEMEM free-#define MEM_INIT memset---//**************************************-// Basic Types-//**************************************-#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively-#define BYTE unsigned __int8-#define U16 unsigned __int16-#define U32 unsigned __int32-#define S32 __int32-#define U64 unsigned __int64-#else-#include <stdint.h>-#define BYTE uint8_t-#define U16 uint16_t-#define U32 uint32_t-#define S32 int32_t-#define U64 uint64_t-#endif--#ifndef LZ4_FORCE_UNALIGNED_ACCESS-#pragma pack(push, 1) -#endif--typedef struct _U16_S { U16 v; } U16_S;-typedef struct _U32_S { U32 v; } U32_S;-typedef struct _U64_S { U64 v; } U64_S;--#ifndef LZ4_FORCE_UNALIGNED_ACCESS-#pragma pack(pop) -#endif--#define A64(x) (((U64_S *)(x))->v)-#define A32(x) (((U32_S *)(x))->v)-#define A16(x) (((U16_S *)(x))->v)---//**************************************-// Constants-//**************************************-#define MINMATCH 4--#define DICTIONARY_LOGSIZE 16-#define MAXD (1<<DICTIONARY_LOGSIZE)-#define MAXD_MASK ((U32)(MAXD - 1))-#define MAX_DISTANCE (MAXD - 1)--#define HASH_LOG (DICTIONARY_LOGSIZE-1)-#define HASHTABLESIZE (1 << HASH_LOG)-#define HASH_MASK (HASHTABLESIZE - 1)--#define MAX_NB_ATTEMPTS 256--#define ML_BITS 4-#define ML_MASK (size_t)((1U<<ML_BITS)-1)-#define RUN_BITS (8-ML_BITS)-#define RUN_MASK ((1U<<RUN_BITS)-1)--#define COPYLENGTH 8-#define LASTLITERALS 5-#define MFLIMIT (COPYLENGTH+MINMATCH)-#define MINLENGTH (MFLIMIT+1)-#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)---//**************************************-// Architecture-specific macros-//**************************************-#if LZ4_ARCH64 // 64-bit-#define STEPSIZE 8-#define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8;-#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d)-#define UARCH U64-#define AARCH A64-#define HTYPE U32-#define INITBASE(b,s) const BYTE* const b = s-#else // 32-bit-#define STEPSIZE 4-#define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4;-#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);-#define UARCH U32-#define AARCH A32-#define HTYPE const BYTE*-#define INITBASE(b,s) const int b = 0-#endif--#if defined(LZ4_BIG_ENDIAN)-#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = bswap16(v); d = (s) - v; }-#define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = bswap16(v); A16(p) = v; p+=2; }-#else // Little Endian-#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }-#define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; }-#endif---//************************************************************-// Local Types-//************************************************************-typedef struct -{- const BYTE* base;- HTYPE hashTable[HASHTABLESIZE];- U16 chainTable[MAXD];- const BYTE* nextToUpdate;-} LZ4HC_Data_Structure;---//**************************************-// Macros-//**************************************-#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);-#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; }-#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))-#define HASH_VALUE(p) HASH_FUNCTION(*(U32*)(p))-#define HASH_POINTER(p) (HashTable[HASH_VALUE(p)] + base)-#define DELTANEXT(p) chainTable[(size_t)(p) & MAXD_MASK] -#define GETNEXT(p) ((p) - (size_t)DELTANEXT(p))-#define ADD_HASH(p) { size_t delta = (p) - HASH_POINTER(p); if (delta>MAX_DISTANCE) delta = MAX_DISTANCE; DELTANEXT(p) = (U16)delta; HashTable[HASH_VALUE(p)] = (p) - base; }---//**************************************-// Private functions-//**************************************-#if LZ4_ARCH64--inline static int LZ4_NbCommonBytes (register U64 val)-{-#if defined(LZ4_BIG_ENDIAN)- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanReverse64( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_clzll(val) >> 3); - #else- int r;- if (!(val>>32)) { r=4; } else { r=0; val>>=32; }- if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }- r += (!val);- return r;- #endif-#else- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanForward64( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_ctzll(val) >> 3); - #else- static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };- return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];- #endif-#endif-}--#else--inline static int LZ4_NbCommonBytes (register U32 val)-{-#if defined(LZ4_BIG_ENDIAN)- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanReverse( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_clz(val) >> 3); - #else- int r;- if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }- r += (!val);- return r;- #endif-#else- #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)- unsigned long r = 0;- _BitScanForward( &r, val );- return (int)(r>>3);- #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)- return (__builtin_ctz(val) >> 3); - #else- static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };- return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];- #endif-#endif-}--#endif---inline static int LZ4HC_Init (LZ4HC_Data_Structure* hc4, const BYTE* base)-{- MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable));- MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));- hc4->nextToUpdate = base + LZ4_ARCH64;- hc4->base = base;- return 1;-}---inline static void* LZ4HC_Create (const BYTE* base)-{- void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));-- LZ4HC_Init (hc4, base);- return hc4;-}---inline static int LZ4HC_Free (void** LZ4HC_Data)-{- FREEMEM(*LZ4HC_Data);- *LZ4HC_Data = NULL;- return (1);-}---inline static void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip)-{- U16* chainTable = hc4->chainTable;- HTYPE* HashTable = hc4->hashTable;- INITBASE(base,hc4->base);-- while(hc4->nextToUpdate < ip)- {- ADD_HASH(hc4->nextToUpdate);- hc4->nextToUpdate++;- }-}---inline static int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* const matchlimit, const BYTE** matchpos)-{- U16* const chainTable = hc4->chainTable;- HTYPE* const HashTable = hc4->hashTable;- const BYTE* ref;- INITBASE(base,hc4->base);- int nbAttempts=MAX_NB_ATTEMPTS;- int ml=0;-- // HC4 match finder- LZ4HC_Insert(hc4, ip);- ref = HASH_POINTER(ip);- while ((ref > (ip-MAX_DISTANCE)) && (nbAttempts))- {- nbAttempts--;- if (*(ref+ml) == *(ip+ml))- if (*(U32*)ref == *(U32*)ip)- {- const BYTE* reft = ref+MINMATCH;- const BYTE* ipt = ip+MINMATCH;-- while (ipt<matchlimit-(STEPSIZE-1))- {- UARCH diff = AARCH(reft) ^ AARCH(ipt);- if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }- ipt += LZ4_NbCommonBytes(diff);- goto _endCount;- }- if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }- if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }- if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;-_endCount:-- if (ipt-ip > ml) { ml = (int)(ipt-ip); *matchpos = ref; }- }- ref = GETNEXT(ref);- }-- return ml;-}---inline static int LZ4HC_InsertAndGetWiderMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* startLimit, const BYTE* matchlimit, int longest, const BYTE** matchpos, const BYTE** startpos)-{- U16* const chainTable = hc4->chainTable;- HTYPE* const HashTable = hc4->hashTable;- INITBASE(base,hc4->base);- const BYTE* ref;- int nbAttempts = MAX_NB_ATTEMPTS;- int delta = (int)(ip-startLimit);-- // First Match- LZ4HC_Insert(hc4, ip);- ref = HASH_POINTER(ip);-- while ((ref > ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts))- {- nbAttempts--;- if (*(startLimit + longest) == *(ref - delta + longest))- if (*(U32*)ref == *(U32*)ip)- {- const BYTE* reft = ref+MINMATCH;- const BYTE* ipt = ip+MINMATCH;- const BYTE* startt = ip;-- while (ipt<matchlimit-(STEPSIZE-1))- {- UARCH diff = AARCH(reft) ^ AARCH(ipt);- if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; }- ipt += LZ4_NbCommonBytes(diff);- goto _endCount;- }- if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; }- if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; }- if ((ipt<matchlimit) && (*reft == *ipt)) ipt++;-_endCount:-- reft = ref;- while ((startt>startLimit) && (reft > hc4->base) && (startt[-1] == reft[-1])) {startt--; reft--;}-- if ((ipt-startt) > longest)- {- longest = (int)(ipt-startt);- *matchpos = reft;- *startpos = startt;- }- }- ref = GETNEXT(ref);- }-- return longest;-}---inline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int ml, const BYTE* ref)-{- int length, len; - BYTE* token;-- // Encode Literal length- length = (int)(*ip - *anchor);- token = (*op)++;- if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *(*op)++ = 255; *(*op)++ = (BYTE)len; } - else *token = (length<<ML_BITS);-- // Copy Literals- LZ4_BLINDCOPY(*anchor, *op, length);-- // Encode Offset- LZ4_WRITE_LITTLEENDIAN_16(*op,(U16)(*ip-ref));-- // Encode MatchLength- len = (int)(ml-MINMATCH);- if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *(*op)++ = 255; *(*op)++ = 255; } if (len > 254) { len-=255; *(*op)++ = 255; } *(*op)++ = (BYTE)len; } - else *token += len; -- // Prepare next loop- *ip += ml;- *anchor = *ip; -- return 0;-}---//****************************-// Compression CODE-//****************************--int LZ4_compressHCCtx(LZ4HC_Data_Structure* ctx,- const char* source, - char* dest,- int isize)-{ - const BYTE* ip = (const BYTE*) source;- const BYTE* anchor = ip;- const BYTE* const iend = ip + isize;- const BYTE* const mflimit = iend - MFLIMIT;- const BYTE* const matchlimit = (iend - LASTLITERALS);-- BYTE* op = (BYTE*) dest;-- int ml, ml2, ml3, ml0;- const BYTE* ref=NULL;- const BYTE* start2=NULL;- const BYTE* ref2=NULL;- const BYTE* start3=NULL;- const BYTE* ref3=NULL;- const BYTE* start0;- const BYTE* ref0;-- ip++;-- // Main Loop- while (ip < mflimit)- {- ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, (&ref));- if (!ml) { ip++; continue; }-- // saved, in case we would skip too much- start0 = ip;- ref0 = ref;- ml0 = ml;--_Search2:- if (ip+ml < mflimit)- ml2 = LZ4HC_InsertAndGetWiderMatch(ctx, ip + ml - 2, ip + 1, matchlimit, ml, &ref2, &start2);- else ml2=ml;-- if (ml2 == ml) // No better match- {- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);- continue;- }-- if (start0 < ip)- {- if (start2 < ip + ml0) // empirical- {- ip = start0;- ref = ref0;- ml = ml0;- }- }-- // Here, start0==ip- if ((start2 - ip) < 3) // First Match too small : removed- {- ml = ml2;- ip = start2;- ref =ref2;- goto _Search2;- }--_Search3:- // Currently we have :- // ml2 > ml1, and- // ip1+3 <= ip2 (usually < ip1+ml1)- if ((start2 - ip) < OPTIMAL_ML)- {- int correction;- int new_ml = ml;- if (new_ml > OPTIMAL_ML) new_ml = OPTIMAL_ML;- if (ip+new_ml > start2 + ml2 - MINMATCH) new_ml = (int)(start2 - ip) + ml2 - MINMATCH;- correction = new_ml - (int)(start2 - ip);- if (correction > 0)- {- start2 += correction;- ref2 += correction;- ml2 -= correction;- }- }- // Now, we have start2 = ip+new_ml, with new_ml=min(ml, OPTIMAL_ML=18)-- if (start2 + ml2 < mflimit)- ml3 = LZ4HC_InsertAndGetWiderMatch(ctx, start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3);- else ml3=ml2;-- if (ml3 == ml2) // No better match : 2 sequences to encode- {- // ip & ref are known; Now for ml- if (start2 < ip+ml)- {- if ((start2 - ip) < OPTIMAL_ML)- {- int correction;- if (ml > OPTIMAL_ML) ml = OPTIMAL_ML;- if (ip+ml > start2 + ml2 - MINMATCH) ml = (int)(start2 - ip) + ml2 - MINMATCH;- correction = ml - (int)(start2 - ip);- if (correction > 0)- {- start2 += correction;- ref2 += correction;- ml2 -= correction;- }- }- else- {- ml = (int)(start2 - ip);- }- }- // Now, encode 2 sequences- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);- ip = start2;- LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2);- continue;- }-- if (start3 < ip+ml+3) // Not enough space for match 2 : remove it- {- if (start3 >= (ip+ml)) // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1- {- if (start2 < ip+ml)- {- int correction = (int)(ip+ml - start2);- start2 += correction;- ref2 += correction;- ml2 -= correction;- if (ml2 < MINMATCH)- {- start2 = start3;- ref2 = ref3;- ml2 = ml3;- }- }-- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);- ip = start3;- ref = ref3;- ml = ml3;-- start0 = start2;- ref0 = ref2;- ml0 = ml2;- goto _Search2;- }-- start2 = start3;- ref2 = ref3;- ml2 = ml3;- goto _Search3;- }-- // OK, now we have 3 ascending matches; let's write at least the first one- // ip & ref are known; Now for ml- if (start2 < ip+ml)- {- if ((start2 - ip) < (int)ML_MASK)- {- int correction;- if (ml > OPTIMAL_ML) ml = OPTIMAL_ML;- if (ip + ml > start2 + ml2 - MINMATCH) ml = (int)(start2 - ip) + ml2 - MINMATCH;- correction = ml - (int)(start2 - ip);- if (correction > 0)- {- start2 += correction;- ref2 += correction;- ml2 -= correction;- }- }- else- {- ml = (int)(start2 - ip);- }- }- LZ4_encodeSequence(&ip, &op, &anchor, ml, ref);-- ip = start2;- ref = ref2;- ml = ml2;-- start2 = start3;- ref2 = ref3;- ml2 = ml3;-- goto _Search3;-- }-- // Encode Last Literals- {- int lastRun = (int)(iend - anchor);- if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; } - else *op++ = (lastRun<<ML_BITS);- memcpy(op, anchor, iend - anchor);- op += iend-anchor;- } -- // End- return (int) (((char*)op)-dest);-}---int LZ4_compressHC(const char* source, - char* dest,- int isize)-{- void* ctx = LZ4HC_Create((const BYTE*)source);- int result = LZ4_compressHCCtx(ctx, source, dest, isize);- LZ4HC_Free (&ctx);-- return result;-}--+/* + LZ4 HC - High Compression Mode of LZ4 + Copyright (C) 2011-2012, Yann Collet. + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html + - LZ4 source repository : http://code.google.com/p/lz4/ +*/ + + +//************************************** +// CPU Feature Detection +//************************************** +// 32 or 64 bits ? +#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) ) // Detects 64 bits mode +# define LZ4_ARCH64 1 +#else +# define LZ4_ARCH64 0 +#endif + +// Little Endian or Big Endian ? +// Overwrite the #define below if you know your architecture endianess +#if defined (__GLIBC__) +# include <endian.h> +# if (__BYTE_ORDER == __BIG_ENDIAN) +# define LZ4_BIG_ENDIAN 1 +# endif +#elif (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN)) +# define LZ4_BIG_ENDIAN 1 +#elif defined(__sparc) || defined(__sparc__) \ + || defined(__ppc__) || defined(_POWER) || defined(__powerpc__) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) \ + || defined(__hpux) || defined(__hppa) \ + || defined(_MIPSEB) || defined(__s390__) +# define LZ4_BIG_ENDIAN 1 +#else +// Little Endian assumed. PDP Endian and other very rare endian format are unsupported. +#endif + +// Unaligned memory access is automatically enabled for "common" CPU, such as x86. +// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected +// If you know your target CPU supports unaligned memory access, you want to force this option manually to improve performance +#if defined(__ARM_FEATURE_UNALIGNED) +# define LZ4_FORCE_UNALIGNED_ACCESS 1 +#endif + +// Define this parameter if your target system or compiler does not support hardware bit count +#if defined(_MSC_VER) && defined(_WIN32_WCE) // Visual Studio for Windows CE does not support Hardware bit count +# define LZ4_FORCE_SW_BITCOUNT +#endif + + +//************************************** +// Compiler Options +//************************************** +#if __STDC_VERSION__ >= 199901L // C99 + /* "restrict" is a known keyword */ +#else +# define restrict // Disable restrict +#endif + +#ifdef _MSC_VER +# define inline __inline // Visual is not C99, but supports some kind of inline +# define forceinline __forceinline +# include <intrin.h> // For Visual 2005 +# if LZ4_ARCH64 // 64-bit +# pragma intrinsic(_BitScanForward64) // For Visual 2005 +# pragma intrinsic(_BitScanReverse64) // For Visual 2005 +# else +# pragma intrinsic(_BitScanForward) // For Visual 2005 +# pragma intrinsic(_BitScanReverse) // For Visual 2005 +# endif +#else +# ifdef __GNUC__ +# define forceinline inline __attribute__((always_inline)) +# else +# define forceinline inline +# endif +#endif + +#ifdef _MSC_VER // Visual Studio +#define lz4_bswap16(x) _byteswap_ushort(x) +#else +#define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))) +#endif + + +//************************************** +// Includes +//************************************** +#include <stdlib.h> // calloc, free +#include <string.h> // memset, memcpy +#include "lz4hc.h" + +#define ALLOCATOR(s) calloc(1,s) +#define FREEMEM free +#define MEM_INIT memset + + +//************************************** +// Basic Types +//************************************** +#if defined(_MSC_VER) // Visual Studio does not support 'stdint' natively +#define BYTE unsigned __int8 +#define U16 unsigned __int16 +#define U32 unsigned __int32 +#define S32 __int32 +#define U64 unsigned __int64 +#else +#include <stdint.h> +#define BYTE uint8_t +#define U16 uint16_t +#define U32 uint32_t +#define S32 int32_t +#define U64 uint64_t +#endif + +#ifndef LZ4_FORCE_UNALIGNED_ACCESS +#pragma pack(push, 1) +#endif + +typedef struct _U16_S { U16 v; } U16_S; +typedef struct _U32_S { U32 v; } U32_S; +typedef struct _U64_S { U64 v; } U64_S; + +#ifndef LZ4_FORCE_UNALIGNED_ACCESS +#pragma pack(pop) +#endif + +#define A64(x) (((U64_S *)(x))->v) +#define A32(x) (((U32_S *)(x))->v) +#define A16(x) (((U16_S *)(x))->v) + + +//************************************** +// Constants +//************************************** +#define MINMATCH 4 + +#define DICTIONARY_LOGSIZE 16 +#define MAXD (1<<DICTIONARY_LOGSIZE) +#define MAXD_MASK ((U32)(MAXD - 1)) +#define MAX_DISTANCE (MAXD - 1) + +#define HASH_LOG (DICTIONARY_LOGSIZE-1) +#define HASHTABLESIZE (1 << HASH_LOG) +#define HASH_MASK (HASHTABLESIZE - 1) + +#define MAX_NB_ATTEMPTS 256 + +#define ML_BITS 4 +#define ML_MASK (size_t)((1U<<ML_BITS)-1) +#define RUN_BITS (8-ML_BITS) +#define RUN_MASK ((1U<<RUN_BITS)-1) + +#define COPYLENGTH 8 +#define LASTLITERALS 5 +#define MFLIMIT (COPYLENGTH+MINMATCH) +#define MINLENGTH (MFLIMIT+1) +#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH) + + +//************************************** +// Architecture-specific macros +//************************************** +#if LZ4_ARCH64 // 64-bit +#define STEPSIZE 8 +#define LZ4_COPYSTEP(s,d) A64(d) = A64(s); d+=8; s+=8; +#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d) +#define UARCH U64 +#define AARCH A64 +#define HTYPE U32 +#define INITBASE(b,s) const BYTE* const b = s +#else // 32-bit +#define STEPSIZE 4 +#define LZ4_COPYSTEP(s,d) A32(d) = A32(s); d+=4; s+=4; +#define LZ4_COPYPACKET(s,d) LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d); +#define UARCH U32 +#define AARCH A32 +#define HTYPE const BYTE* +#define INITBASE(b,s) const int b = 0 +#endif + +#if defined(LZ4_BIG_ENDIAN) +#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; } +#define LZ4_WRITE_LITTLEENDIAN_16(p,i) { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; } +#else // Little Endian +#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); } +#define LZ4_WRITE_LITTLEENDIAN_16(p,v) { A16(p) = v; p+=2; } +#endif + + +//************************************************************ +// Local Types +//************************************************************ +typedef struct +{ + const BYTE* base; + HTYPE hashTable[HASHTABLESIZE]; + U16 chainTable[MAXD]; + const BYTE* nextToUpdate; +} LZ4HC_Data_Structure; + + +//************************************** +// Macros +//************************************** +#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e); +#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; } +#define HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG)) +#define HASH_VALUE(p) HASH_FUNCTION(A32(p)) +#define HASH_POINTER(p) (HashTable[HASH_VALUE(p)] + base) +#define DELTANEXT(p) chainTable[(size_t)(p) & MAXD_MASK] +#define GETNEXT(p) ((p) - (size_t)DELTANEXT(p)) + + +//************************************** +// Private functions +//************************************** +#if LZ4_ARCH64 + +inline static int LZ4_NbCommonBytes (register U64 val) +{ +#if defined(LZ4_BIG_ENDIAN) + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanReverse64( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_clzll(val) >> 3); + #else + int r; + if (!(val>>32)) { r=4; } else { r=0; val>>=32; } + if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; } + r += (!val); + return r; + #endif +#else + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r = 0; + _BitScanForward64( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_ctzll(val) >> 3); + #else + static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 }; + return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58]; + #endif +#endif +} + +#else + +inline static int LZ4_NbCommonBytes (register U32 val) +{ +#if defined(LZ4_BIG_ENDIAN) + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r; + _BitScanReverse( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_clz(val) >> 3); + #else + int r; + if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; } + r += (!val); + return r; + #endif +#else + #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT) + unsigned long r; + _BitScanForward( &r, val ); + return (int)(r>>3); + #elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT) + return (__builtin_ctz(val) >> 3); + #else + static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 }; + return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27]; + #endif +#endif +} + +#endif + + +inline static int LZ4HC_Init (LZ4HC_Data_Structure* hc4, const BYTE* base) +{ + MEM_INIT((void*)hc4->hashTable, 0, sizeof(hc4->hashTable)); + MEM_INIT(hc4->chainTable, 0xFF, sizeof(hc4->chainTable)); + hc4->nextToUpdate = base + LZ4_ARCH64; + hc4->base = base; + return 1; +} + + +inline static void* LZ4HC_Create (const BYTE* base) +{ + void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure)); + + LZ4HC_Init ((LZ4HC_Data_Structure*)hc4, base); + return hc4; +} + + +inline static int LZ4HC_Free (void** LZ4HC_Data) +{ + FREEMEM(*LZ4HC_Data); + *LZ4HC_Data = NULL; + return (1); +} + + +// Update chains up to ip (excluded) +forceinline static void LZ4HC_Insert (LZ4HC_Data_Structure* hc4, const BYTE* ip) +{ + U16* chainTable = hc4->chainTable; + HTYPE* HashTable = hc4->hashTable; + INITBASE(base,hc4->base); + + while(hc4->nextToUpdate < ip) + { + const BYTE* p = hc4->nextToUpdate; + size_t delta = (p) - HASH_POINTER(p); + if (delta>MAX_DISTANCE) delta = MAX_DISTANCE; + DELTANEXT(p) = (U16)delta; + HashTable[HASH_VALUE(p)] = (p) - base; + hc4->nextToUpdate++; + } +} + + +forceinline static size_t LZ4HC_CommonLength (const BYTE* p1, const BYTE* p2, const BYTE* const matchlimit) +{ + const BYTE* p1t = p1; + + while (p1t<matchlimit-(STEPSIZE-1)) + { + UARCH diff = AARCH(p2) ^ AARCH(p1t); + if (!diff) { p1t+=STEPSIZE; p2+=STEPSIZE; continue; } + p1t += LZ4_NbCommonBytes(diff); + return (p1t - p1); + } + if (LZ4_ARCH64) if ((p1t<(matchlimit-3)) && (A32(p2) == A32(p1t))) { p1t+=4; p2+=4; } + if ((p1t<(matchlimit-1)) && (A16(p2) == A16(p1t))) { p1t+=2; p2+=2; } + if ((p1t<matchlimit) && (*p2 == *p1t)) p1t++; + return (p1t - p1); +} + + +forceinline static int LZ4HC_InsertAndFindBestMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* const matchlimit, const BYTE** matchpos) +{ + U16* const chainTable = hc4->chainTable; + HTYPE* const HashTable = hc4->hashTable; + const BYTE* ref; + INITBASE(base,hc4->base); + int nbAttempts=MAX_NB_ATTEMPTS; + size_t ml=0; + + // HC4 match finder + LZ4HC_Insert(hc4, ip); + ref = HASH_POINTER(ip); + +#if 1 + if (ref >= ip-4) // potential repetition + { + if (A32(ref) == A32(ip)) // confirmed + { + const U16 delta = (U16)(ip-ref); + const BYTE* ptr = ip; + const BYTE* end; + ml = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH; + end = ip + ml - (MINMATCH-1); + while(ptr < end-delta) + { + DELTANEXT(ptr) = delta; // Pre-Load + ptr++; + } + do + { + DELTANEXT(ptr) = delta; + HashTable[HASH_VALUE(ptr)] = (ptr) - base; // Head of chain + ptr++; + } while(ptr < end); + hc4->nextToUpdate = end; + *matchpos = ref; + } + ref = GETNEXT(ref); + } +#endif + + while ((ref >= ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts)) + { + nbAttempts--; + if (*(ref+ml) == *(ip+ml)) + if (A32(ref) == A32(ip)) + { + size_t mlt = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH; + if (mlt > ml) { ml = mlt; *matchpos = ref; } + } + ref = GETNEXT(ref); + } + + return (int)ml; +} + + +forceinline static int LZ4HC_InsertAndGetWiderMatch (LZ4HC_Data_Structure* hc4, const BYTE* ip, const BYTE* startLimit, const BYTE* matchlimit, int longest, const BYTE** matchpos, const BYTE** startpos) +{ + U16* const chainTable = hc4->chainTable; + HTYPE* const HashTable = hc4->hashTable; + INITBASE(base,hc4->base); + const BYTE* ref; + int nbAttempts = MAX_NB_ATTEMPTS; + int delta = (int)(ip-startLimit); + + // First Match + LZ4HC_Insert(hc4, ip); + ref = HASH_POINTER(ip); + + while ((ref >= ip-MAX_DISTANCE) && (ref >= hc4->base) && (nbAttempts)) + { + nbAttempts--; + if (*(startLimit + longest) == *(ref - delta + longest)) + if (A32(ref) == A32(ip)) + { +#if 1 + const BYTE* reft = ref+MINMATCH; + const BYTE* ipt = ip+MINMATCH; + const BYTE* startt = ip; + + while (ipt<matchlimit-(STEPSIZE-1)) + { + UARCH diff = AARCH(reft) ^ AARCH(ipt); + if (!diff) { ipt+=STEPSIZE; reft+=STEPSIZE; continue; } + ipt += LZ4_NbCommonBytes(diff); + goto _endCount; + } + if (LZ4_ARCH64) if ((ipt<(matchlimit-3)) && (A32(reft) == A32(ipt))) { ipt+=4; reft+=4; } + if ((ipt<(matchlimit-1)) && (A16(reft) == A16(ipt))) { ipt+=2; reft+=2; } + if ((ipt<matchlimit) && (*reft == *ipt)) ipt++; +_endCount: + reft = ref; +#else + // Easier for code maintenance, but unfortunately slower too + const BYTE* startt = ip; + const BYTE* reft = ref; + const BYTE* ipt = ip + MINMATCH + LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit); +#endif + + while ((startt>startLimit) && (reft > hc4->base) && (startt[-1] == reft[-1])) {startt--; reft--;} + + if ((ipt-startt) > longest) + { + longest = (int)(ipt-startt); + *matchpos = reft; + *startpos = startt; + } + } + ref = GETNEXT(ref); + } + + return longest; +} + + +forceinline static int LZ4_encodeSequence(const BYTE** ip, BYTE** op, const BYTE** anchor, int ml, const BYTE* ref) +{ + int length, len; + BYTE* token; + + // Encode Literal length + length = (int)(*ip - *anchor); + token = (*op)++; + if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *(*op)++ = 255; *(*op)++ = (BYTE)len; } + else *token = (length<<ML_BITS); + + // Copy Literals + LZ4_BLINDCOPY(*anchor, *op, length); + + // Encode Offset + LZ4_WRITE_LITTLEENDIAN_16(*op,(U16)(*ip-ref)); + + // Encode MatchLength + len = (int)(ml-MINMATCH); + if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *(*op)++ = 255; *(*op)++ = 255; } if (len > 254) { len-=255; *(*op)++ = 255; } *(*op)++ = (BYTE)len; } + else *token += len; + + // Prepare next loop + *ip += ml; + *anchor = *ip; + + return 0; +} + + +//**************************** +// Compression CODE +//**************************** + +int LZ4_compressHCCtx(LZ4HC_Data_Structure* ctx, + const char* source, + char* dest, + int isize) +{ + const BYTE* ip = (const BYTE*) source; + const BYTE* anchor = ip; + const BYTE* const iend = ip + isize; + const BYTE* const mflimit = iend - MFLIMIT; + const BYTE* const matchlimit = (iend - LASTLITERALS); + + BYTE* op = (BYTE*) dest; + + int ml, ml2, ml3, ml0; + const BYTE* ref=NULL; + const BYTE* start2=NULL; + const BYTE* ref2=NULL; + const BYTE* start3=NULL; + const BYTE* ref3=NULL; + const BYTE* start0; + const BYTE* ref0; + + ip++; + + // Main Loop + while (ip < mflimit) + { + ml = LZ4HC_InsertAndFindBestMatch (ctx, ip, matchlimit, (&ref)); + if (!ml) { ip++; continue; } + + // saved, in case we would skip too much + start0 = ip; + ref0 = ref; + ml0 = ml; + +_Search2: + if (ip+ml < mflimit) + ml2 = LZ4HC_InsertAndGetWiderMatch(ctx, ip + ml - 2, ip + 1, matchlimit, ml, &ref2, &start2); + else ml2 = ml; + + if (ml2 == ml) // No better match + { + LZ4_encodeSequence(&ip, &op, &anchor, ml, ref); + continue; + } + + if (start0 < ip) + { + if (start2 < ip + ml0) // empirical + { + ip = start0; + ref = ref0; + ml = ml0; + } + } + + // Here, start0==ip + if ((start2 - ip) < 3) // First Match too small : removed + { + ml = ml2; + ip = start2; + ref =ref2; + goto _Search2; + } + +_Search3: + // Currently we have : + // ml2 > ml1, and + // ip1+3 <= ip2 (usually < ip1+ml1) + if ((start2 - ip) < OPTIMAL_ML) + { + int correction; + int new_ml = ml; + if (new_ml > OPTIMAL_ML) new_ml = OPTIMAL_ML; + if (ip+new_ml > start2 + ml2 - MINMATCH) new_ml = (int)(start2 - ip) + ml2 - MINMATCH; + correction = new_ml - (int)(start2 - ip); + if (correction > 0) + { + start2 += correction; + ref2 += correction; + ml2 -= correction; + } + } + // Now, we have start2 = ip+new_ml, with new_ml = min(ml, OPTIMAL_ML=18) + + if (start2 + ml2 < mflimit) + ml3 = LZ4HC_InsertAndGetWiderMatch(ctx, start2 + ml2 - 3, start2, matchlimit, ml2, &ref3, &start3); + else ml3 = ml2; + + if (ml3 == ml2) // No better match : 2 sequences to encode + { + // ip & ref are known; Now for ml + if (start2 < ip+ml) ml = (int)(start2 - ip); + // Now, encode 2 sequences + LZ4_encodeSequence(&ip, &op, &anchor, ml, ref); + ip = start2; + LZ4_encodeSequence(&ip, &op, &anchor, ml2, ref2); + continue; + } + + if (start3 < ip+ml+3) // Not enough space for match 2 : remove it + { + if (start3 >= (ip+ml)) // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1 + { + if (start2 < ip+ml) + { + int correction = (int)(ip+ml - start2); + start2 += correction; + ref2 += correction; + ml2 -= correction; + if (ml2 < MINMATCH) + { + start2 = start3; + ref2 = ref3; + ml2 = ml3; + } + } + + LZ4_encodeSequence(&ip, &op, &anchor, ml, ref); + ip = start3; + ref = ref3; + ml = ml3; + + start0 = start2; + ref0 = ref2; + ml0 = ml2; + goto _Search2; + } + + start2 = start3; + ref2 = ref3; + ml2 = ml3; + goto _Search3; + } + + // OK, now we have 3 ascending matches; let's write at least the first one + // ip & ref are known; Now for ml + if (start2 < ip+ml) + { + if ((start2 - ip) < (int)ML_MASK) + { + int correction; + if (ml > OPTIMAL_ML) ml = OPTIMAL_ML; + if (ip + ml > start2 + ml2 - MINMATCH) ml = (int)(start2 - ip) + ml2 - MINMATCH; + correction = ml - (int)(start2 - ip); + if (correction > 0) + { + start2 += correction; + ref2 += correction; + ml2 -= correction; + } + } + else + { + ml = (int)(start2 - ip); + } + } + LZ4_encodeSequence(&ip, &op, &anchor, ml, ref); + + ip = start2; + ref = ref2; + ml = ml2; + + start2 = start3; + ref2 = ref3; + ml2 = ml3; + + goto _Search3; + + } + + // Encode Last Literals + { + int lastRun = (int)(iend - anchor); + if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun > 254 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; } + else *op++ = (lastRun<<ML_BITS); + memcpy(op, anchor, iend - anchor); + op += iend-anchor; + } + + // End + return (int) (((char*)op)-dest); +} + + +int LZ4_compressHC(const char* source, + char* dest, + int isize) +{ + void* ctx = LZ4HC_Create((const BYTE*)source); + int result = LZ4_compressHCCtx(ctx, source, dest, isize); + LZ4HC_Free (&ctx); + + return result; +} + +
src/cbits/lz4hc.h view
@@ -1,60 +1,60 @@-/*- LZ4 HC - High Compression Mode of LZ4- Header File- Copyright (C) 2011-2012, Yann Collet.- BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)-- Redistribution and use in source and binary forms, with or without- modification, are permitted provided that the following conditions are- met:-- * Redistributions of source code must retain the above copyright- notice, this list of conditions and the following disclaimer.- * Redistributions in binary form must reproduce the above- copyright notice, this list of conditions and the following disclaimer- in the documentation and/or other materials provided with the- distribution.-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,- SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.-- You can contact the author at :- - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html- - LZ4 source repository : http://code.google.com/p/lz4/-*/-#pragma once---#if defined (__cplusplus)-extern "C" {-#endif---int LZ4_compressHC (const char* source, char* dest, int isize);--/*-LZ4_compressHC :- return : the number of bytes in compressed buffer dest- note : destination buffer must be already allocated. - To avoid any problem, size it to handle worst cases situations (input data not compressible)- Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h")-*/---/* Note :-Decompression functions are provided within regular LZ4 source code (see "lz4.h") (BSD license)-*/---#if defined (__cplusplus)-}-#endif+/* + LZ4 HC - High Compression Mode of LZ4 + Header File + Copyright (C) 2011-2012, Yann Collet. + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html + - LZ4 source repository : http://code.google.com/p/lz4/ +*/ +#pragma once + + +#if defined (__cplusplus) +extern "C" { +#endif + + +int LZ4_compressHC (const char* source, char* dest, int isize); + +/* +LZ4_compressHC : + return : the number of bytes in compressed buffer dest + note : destination buffer must be already allocated. + To avoid any problem, size it to handle worst cases situations (input data not compressible) + Worst case size evaluation is provided by function LZ4_compressBound() (see "lz4.h") +*/ + + +/* Note : +Decompression functions are provided within regular LZ4 source code (see "lz4.h") (BSD license) +*/ + + +#if defined (__cplusplus) +} +#endif