hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/io/compress/lz4/lz4hc.c - hadoop-common - Git at Google

 /*
    LZ4 HC - High Compression Mode of LZ4
    Copyright (C) 2011-2013, 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/
 */

 /*
 Note : this source file requires "lz4hc_encoder.h"
 */


 //**************************************
 // Memory routines
 //**************************************
 #include <stdlib.h>   // calloc, free
 #define ALLOCATOR(s)  calloc(1,s)
 #define FREEMEM       free
 #include <string.h>   // memset, memcpy
 #define MEM_INIT      memset


 //**************************************
 // CPU Feature Detection
 //**************************************
 // 32 or 64 bits ?
 #if (defined(__x86_64__) || defined(_M_X64) || defined(_WIN64) \
   || defined(__powerpc64__) || defined(__ppc64__) || defined(__PPC64__) \
   || defined(__64BIT__) || defined(_LP64) || defined(__LP64__) \
   || defined(__ia64) || defined(__itanium__) || defined(_M_IA64) )   // 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(__powerpc__) || defined(__ppc__) || defined(__PPC__) \
    || 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 defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   // C99
   /* "restrict" is a known keyword */
 #else
 #  define restrict  // Disable restrict
 #endif

 #ifdef _MSC_VER    // Visual Studio
 #  define forceinline static __forceinline
 #  include <intrin.h>                    // For Visual 2005
 #  if LZ4_ARCH64   // 64-bits
 #    pragma intrinsic(_BitScanForward64) // For Visual 2005
 #    pragma intrinsic(_BitScanReverse64) // For Visual 2005
 #  else            // 32-bits
 #    pragma intrinsic(_BitScanForward)   // For Visual 2005
 #    pragma intrinsic(_BitScanReverse)   // For Visual 2005
 #  endif
 #  pragma warning(disable : 4127)        // disable: C4127: conditional expression is constant
 #  pragma warning(disable : 4701)        // disable: C4701: potentially uninitialized local variable used
 #else
 #  ifdef __GNUC__
 #    define forceinline static inline __attribute__((always_inline))
 #  else
 #    define forceinline static 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 "lz4hc.h"
 #include "lz4.h"


 //**************************************
 // Basic Types
 //**************************************
 #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   // C99
 # include <stdint.h>
   typedef uint8_t  BYTE;
   typedef uint16_t U16;
   typedef uint32_t U32;
   typedef  int32_t S32;
   typedef uint64_t U64;
 #else
   typedef unsigned char       BYTE;
   typedef unsigned short      U16;
   typedef unsigned int        U32;
   typedef   signed int        S32;
   typedef unsigned long long  U64;
 #endif

 #if defined(__GNUC__)  && !defined(LZ4_FORCE_UNALIGNED_ACCESS)
 #  define _PACKED __attribute__ ((packed))
 #else
 #  define _PACKED
 #endif

 #if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
 #  ifdef __IBMC__
 #    pragma pack(1)
 #  else
 #    pragma pack(push, 1)
 #  endif
 #endif

 typedef struct _U16_S { U16 v; } _PACKED U16_S;
 typedef struct _U32_S { U32 v; } _PACKED U32_S;
 typedef struct _U64_S { U64 v; } _PACKED U64_S;

 #if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
 #  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)

 #define KB *(1U<<10)
 #define MB *(1U<<20)
 #define GB *(1U<<30)


 //**************************************
 // 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
 #  define HTYPE                 U32
 #  define INITBASE(b,s)         const BYTE* const b = s
 #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* inputBuffer;
     const BYTE* base;
     const BYTE* end;
     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

 forceinline 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

 forceinline 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


 forceinline int LZ4_InitHC (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 + 1;
     hc4->base = base;
     hc4->inputBuffer = base;
     hc4->end = base;
     return 1;
 }


 void* LZ4_createHC (const char* slidingInputBuffer)
 {
     void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
     LZ4_InitHC ((LZ4HC_Data_Structure*)hc4, (const BYTE*)slidingInputBuffer);
     return hc4;
 }


 int LZ4_freeHC (void* LZ4HC_Data)
 {
     FREEMEM(LZ4HC_Data);
     return (0);
 }


 // Update chains up to ip (excluded)
 forceinline 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* const 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)] = (HTYPE)((p) - base);
         hc4->nextToUpdate++;
     }
 }


 char* LZ4_slideInputBufferHC(void* LZ4HC_Data)
 {
     LZ4HC_Data_Structure* hc4 = (LZ4HC_Data_Structure*)LZ4HC_Data;
     U32 distance = (U32)(hc4->end - hc4->inputBuffer) - 64 KB;
     distance = (distance >> 16) << 16;   // Must be a multiple of 64 KB
     LZ4HC_Insert(hc4, hc4->end - MINMATCH);
     memcpy((void*)(hc4->end - 64 KB - distance), (const void*)(hc4->end - 64 KB), 64 KB);
     hc4->nextToUpdate -= distance;
     hc4->base -= distance;
     if ((U32)(hc4->inputBuffer - hc4->base) > 1 GB + 64 KB)   // Avoid overflow
     {
         int i;
         hc4->base += 1 GB;
         for (i=0; i<HASHTABLESIZE; i++) hc4->hashTable[i] -= 1 GB;
     }
     hc4->end -= distance;
     return (char*)(hc4->end);
 }


 forceinline 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 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 repl=0, ml=0;
     U16 delta=0;  // useless assignment, to remove an uninitialization warning

     // HC4 match finder
     LZ4HC_Insert(hc4, ip);
     ref = HASH_POINTER(ip);

 #define REPEAT_OPTIMIZATION
 #ifdef REPEAT_OPTIMIZATION
     // Detect repetitive sequences of length <= 4
     if ((U32)(ip-ref) <= 4)        // potential repetition
     {
         if (A32(ref) == A32(ip))   // confirmed
         {
             delta = (U16)(ip-ref);
             repl = ml  = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH;
             *matchpos = ref;
         }
         ref = GETNEXT(ref);
     }
 #endif

     while (((U32)(ip-ref) <= MAX_DISTANCE) && (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);
     }

 #ifdef REPEAT_OPTIMIZATION
     // Complete table
     if (repl)
     {
         const BYTE* ptr = ip;
         const BYTE* end;

         end = ip + repl - (MINMATCH-1);
         while(ptr < end-delta)
         {
             DELTANEXT(ptr) = delta;    // Pre-Load
             ptr++;
         }
         do
         {
             DELTANEXT(ptr) = delta;
             HashTable[HASH_VALUE(ptr)] = (HTYPE)((ptr) - base);     // Head of chain
             ptr++;
         } while(ptr < end);
         hc4->nextToUpdate = end;
     }
 #endif

     return (int)ml;
 }


 forceinline 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 (((U32)(ip-ref) <= MAX_DISTANCE) && (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->inputBuffer) && (startt[-1] == reft[-1])) {startt--; reft--;}

             if ((ipt-startt) > longest)
             {
                 longest = (int)(ipt-startt);
                 *matchpos = reft;
                 *startpos = startt;
             }
         }
         ref = GETNEXT(ref);
     }

     return longest;
 }


 //**************************************
 // Compression functions
 //**************************************

 /*
 int LZ4_compressHC(
                  const char* source,
                  char* dest,
                  int inputSize)

 Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
 Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
 return : the number of bytes written in buffer 'dest'
 */
 #define FUNCTION_NAME LZ4_compressHC
 #include "lz4hc_encoder.h"


 /*
 int LZ4_compressHC_limitedOutput(
                  const char* source,
                  char* dest,
                  int inputSize,
                  int maxOutputSize)

 Compress 'inputSize' 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
 */
 #define FUNCTION_NAME LZ4_compressHC_limitedOutput
 #define LIMITED_OUTPUT
 #include "lz4hc_encoder.h"
	/*
	LZ4 HC - High Compression Mode of LZ4
	Copyright (C) 2011-2013, 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/
	*/

	/*
	Note : this source file requires "lz4hc_encoder.h"
	*/


	//**************************************
	// Memory routines
	//**************************************
	#include <stdlib.h> // calloc, free
	#define ALLOCATOR(s) calloc(1,s)
	#define FREEMEM free
	#include <string.h> // memset, memcpy
	#define MEM_INIT memset


	//**************************************
	// CPU Feature Detection
	//**************************************
	// 32 or 64 bits ?
	#if (defined(__x86_64__) \|\| defined(_M_X64) \|\| defined(_WIN64) \
	\|\| defined(__powerpc64__) \|\| defined(__ppc64__) \|\| defined(__PPC64__) \
	\|\| defined(__64BIT__) \|\| defined(_LP64) \|\| defined(__LP64__) \
	\|\| defined(__ia64) \|\| defined(__itanium__) \|\| defined(_M_IA64) ) // 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(__powerpc__) \|\| defined(__ppc__) \|\| defined(__PPC__) \
	\|\| 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 defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L // C99
	/* "restrict" is a known keyword */
	#else
	# define restrict // Disable restrict
	#endif

	#ifdef _MSC_VER // Visual Studio
	# define forceinline static __forceinline
	# include <intrin.h> // For Visual 2005
	# if LZ4_ARCH64 // 64-bits
	# pragma intrinsic(_BitScanForward64) // For Visual 2005
	# pragma intrinsic(_BitScanReverse64) // For Visual 2005
	# else // 32-bits
	# pragma intrinsic(_BitScanForward) // For Visual 2005
	# pragma intrinsic(_BitScanReverse) // For Visual 2005
	# endif
	# pragma warning(disable : 4127) // disable: C4127: conditional expression is constant
	# pragma warning(disable : 4701) // disable: C4701: potentially uninitialized local variable used
	#else
	# ifdef __GNUC__
	# define forceinline static inline __attribute__((always_inline))
	# else
	# define forceinline static 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 "lz4hc.h"
	#include "lz4.h"


	//**************************************
	// Basic Types
	//**************************************
	#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L // C99
	# include <stdint.h>
	typedef uint8_t BYTE;
	typedef uint16_t U16;
	typedef uint32_t U32;
	typedef int32_t S32;
	typedef uint64_t U64;
	#else
	typedef unsigned char BYTE;
	typedef unsigned short U16;
	typedef unsigned int U32;
	typedef signed int S32;
	typedef unsigned long long U64;
	#endif

	#if defined(__GNUC__) && !defined(LZ4_FORCE_UNALIGNED_ACCESS)
	# define _PACKED __attribute__ ((packed))
	#else
	# define _PACKED
	#endif

	#if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
	# ifdef __IBMC__
	# pragma pack(1)
	# else
	# pragma pack(push, 1)
	# endif
	#endif

	typedef struct _U16_S { U16 v; } _PACKED U16_S;
	typedef struct _U32_S { U32 v; } _PACKED U32_S;
	typedef struct _U64_S { U64 v; } _PACKED U64_S;

	#if !defined(LZ4_FORCE_UNALIGNED_ACCESS) && !defined(__GNUC__)
	# 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)

	#define KB *(1U<<10)
	#define MB *(1U<<20)
	#define GB *(1U<<30)


	//**************************************
	// 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
	# define HTYPE U32
	# define INITBASE(b,s) const BYTE* const b = s
	#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* inputBuffer;
	const BYTE* base;
	const BYTE* end;
	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

	forceinline 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

	forceinline 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


	forceinline int LZ4_InitHC (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 + 1;
	hc4->base = base;
	hc4->inputBuffer = base;
	hc4->end = base;
	return 1;
	}


	void* LZ4_createHC (const char* slidingInputBuffer)
	{
	void* hc4 = ALLOCATOR(sizeof(LZ4HC_Data_Structure));
	LZ4_InitHC ((LZ4HC_Data_Structure)hc4, (const BYTE)slidingInputBuffer);
	return hc4;
	}


	int LZ4_freeHC (void* LZ4HC_Data)
	{
	FREEMEM(LZ4HC_Data);
	return (0);
	}


	// Update chains up to ip (excluded)
	forceinline 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* const 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)] = (HTYPE)((p) - base);
	hc4->nextToUpdate++;
	}
	}


	char* LZ4_slideInputBufferHC(void* LZ4HC_Data)
	{
	LZ4HC_Data_Structure* hc4 = (LZ4HC_Data_Structure*)LZ4HC_Data;
	U32 distance = (U32)(hc4->end - hc4->inputBuffer) - 64 KB;
	distance = (distance >> 16) << 16; // Must be a multiple of 64 KB
	LZ4HC_Insert(hc4, hc4->end - MINMATCH);
	memcpy((void)(hc4->end - 64 KB - distance), (const void)(hc4->end - 64 KB), 64 KB);
	hc4->nextToUpdate -= distance;
	hc4->base -= distance;
	if ((U32)(hc4->inputBuffer - hc4->base) > 1 GB + 64 KB) // Avoid overflow
	{
	int i;
	hc4->base += 1 GB;
	for (i=0; i<HASHTABLESIZE; i++) hc4->hashTable[i] -= 1 GB;
	}
	hc4->end -= distance;
	return (char*)(hc4->end);
	}


	forceinline 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 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 repl=0, ml=0;
	U16 delta=0; // useless assignment, to remove an uninitialization warning

	// HC4 match finder
	LZ4HC_Insert(hc4, ip);
	ref = HASH_POINTER(ip);

	#define REPEAT_OPTIMIZATION
	#ifdef REPEAT_OPTIMIZATION
	// Detect repetitive sequences of length <= 4
	if ((U32)(ip-ref) <= 4) // potential repetition
	{
	if (A32(ref) == A32(ip)) // confirmed
	{
	delta = (U16)(ip-ref);
	repl = ml = LZ4HC_CommonLength(ip+MINMATCH, ref+MINMATCH, matchlimit) + MINMATCH;
	*matchpos = ref;
	}
	ref = GETNEXT(ref);
	}
	#endif

	while (((U32)(ip-ref) <= MAX_DISTANCE) && (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);
	}

	#ifdef REPEAT_OPTIMIZATION
	// Complete table
	if (repl)
	{
	const BYTE* ptr = ip;
	const BYTE* end;

	end = ip + repl - (MINMATCH-1);
	while(ptr < end-delta)
	{
	DELTANEXT(ptr) = delta; // Pre-Load
	ptr++;
	}
	do
	{
	DELTANEXT(ptr) = delta;
	HashTable[HASH_VALUE(ptr)] = (HTYPE)((ptr) - base); // Head of chain
	ptr++;
	} while(ptr < end);
	hc4->nextToUpdate = end;
	}
	#endif

	return (int)ml;
	}


	forceinline 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 (((U32)(ip-ref) <= MAX_DISTANCE) && (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->inputBuffer) && (startt[-1] == reft[-1])) {startt--; reft--;}

	if ((ipt-startt) > longest)
	{
	longest = (int)(ipt-startt);
	*matchpos = reft;
	*startpos = startt;
	}
	}
	ref = GETNEXT(ref);
	}

	return longest;
	}



	//**************************************
	// Compression functions
	//**************************************

	/*
	int LZ4_compressHC(
	const char* source,
	char* dest,
	int inputSize)

	Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.
	Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).
	return : the number of bytes written in buffer 'dest'
	*/
	#define FUNCTION_NAME LZ4_compressHC
	#include "lz4hc_encoder.h"


	/*
	int LZ4_compressHC_limitedOutput(
	const char* source,
	char* dest,
	int inputSize,
	int maxOutputSize)

	Compress 'inputSize' 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
	*/
	#define FUNCTION_NAME LZ4_compressHC_limitedOutput
	#define LIMITED_OUTPUT
	#include "lz4hc_encoder.h"