mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-31 14:15:30 +00:00
259 lines
8.0 KiB
C
259 lines
8.0 KiB
C
/*
|
|
LZ4 Encoder - Part of LZ4 compression algorithm
|
|
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/
|
|
*/
|
|
|
|
/* lz4_encoder.h must be included into lz4.c
|
|
The objective of this file is to create a single LZ4 compression function source
|
|
which will be instanciated multiple times with minor variations
|
|
depending on a set of #define.
|
|
*/
|
|
|
|
|
|
|
|
//****************************
|
|
// Check required defines
|
|
//****************************
|
|
|
|
#ifndef FUNCTION_NAME
|
|
# error "FUNTION_NAME is not defined"
|
|
#endif
|
|
|
|
|
|
//****************************
|
|
// Local definitions
|
|
//****************************
|
|
|
|
#ifdef COMPRESS_64K
|
|
# define HASHLOG (MEMORY_USAGE-1)
|
|
# define CURRENT_H_TYPE U16
|
|
# define CURRENTBASE(base) const BYTE* const base = ip
|
|
#else
|
|
# define HASHLOG (MEMORY_USAGE-2)
|
|
# define CURRENT_H_TYPE HTYPE
|
|
# define CURRENTBASE(base) INITBASE(base)
|
|
#endif
|
|
|
|
#define HASHTABLE_NBCELLS (1U<<HASHLOG)
|
|
#define LZ4_HASH(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASHLOG))
|
|
#define LZ4_HASHVALUE(p) LZ4_HASH(A32(p))
|
|
|
|
|
|
|
|
//****************************
|
|
// Function code
|
|
//****************************
|
|
|
|
int FUNCTION_NAME(
|
|
#ifdef USE_HEAPMEMORY
|
|
void* ctx,
|
|
#endif
|
|
const char* source,
|
|
char* dest,
|
|
int inputSize
|
|
#ifdef LIMITED_OUTPUT
|
|
,int maxOutputSize
|
|
#endif
|
|
)
|
|
{
|
|
#ifdef USE_HEAPMEMORY
|
|
CURRENT_H_TYPE* HashTable = (CURRENT_H_TYPE*)ctx;
|
|
#else
|
|
CURRENT_H_TYPE HashTable[HASHTABLE_NBCELLS] = {0};
|
|
#endif
|
|
|
|
const BYTE* ip = (BYTE*) source;
|
|
CURRENTBASE(base);
|
|
const BYTE* anchor = ip;
|
|
const BYTE* const iend = ip + inputSize;
|
|
const BYTE* const mflimit = iend - MFLIMIT;
|
|
#define matchlimit (iend - LASTLITERALS)
|
|
|
|
BYTE* op = (BYTE*) dest;
|
|
#ifdef LIMITED_OUTPUT
|
|
BYTE* const oend = op + maxOutputSize;
|
|
#endif
|
|
|
|
int length;
|
|
const int skipStrength = SKIPSTRENGTH;
|
|
U32 forwardH;
|
|
|
|
|
|
// Init
|
|
if (inputSize<MINLENGTH) goto _last_literals;
|
|
#ifdef COMPRESS_64K
|
|
if (inputSize>LZ4_64KLIMIT) return 0; // Size too large (not within 64K limit)
|
|
#endif
|
|
#ifdef USE_HEAPMEMORY
|
|
memset((void*)HashTable, 0, HASHTABLESIZE);
|
|
#endif
|
|
|
|
// First Byte
|
|
HashTable[LZ4_HASHVALUE(ip)] = (CURRENT_H_TYPE)(ip - base);
|
|
ip++; forwardH = LZ4_HASHVALUE(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_HASHVALUE(forwardIp);
|
|
ref = base + HashTable[h];
|
|
HashTable[h] = (CURRENT_H_TYPE)(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++;
|
|
#ifdef LIMITED_OUTPUT
|
|
if unlikely(op + length + (2 + 1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
|
|
#endif
|
|
if (length>=(int)RUN_MASK)
|
|
{
|
|
int len = length-RUN_MASK;
|
|
*token=(RUN_MASK<<ML_BITS);
|
|
for(; len >= 255 ; len-=255) *op++ = 255;
|
|
*op++ = (BYTE)len;
|
|
}
|
|
else *token = (BYTE)(length<<ML_BITS);
|
|
|
|
// 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 already 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
|
|
length = (int)(ip - anchor);
|
|
#ifdef LIMITED_OUTPUT
|
|
if unlikely(op + (1 + LASTLITERALS) + (length>>8) > oend) return 0; // Check output limit
|
|
#endif
|
|
if (length>=(int)ML_MASK)
|
|
{
|
|
*token += ML_MASK;
|
|
length -= ML_MASK;
|
|
for (; length > 509 ; length-=510) { *op++ = 255; *op++ = 255; }
|
|
if (length >= 255) { length-=255; *op++ = 255; }
|
|
*op++ = (BYTE)length;
|
|
}
|
|
else *token += (BYTE)length;
|
|
|
|
// Test end of chunk
|
|
if (ip > mflimit) { anchor = ip; break; }
|
|
|
|
// Fill table
|
|
HashTable[LZ4_HASHVALUE(ip-2)] = (CURRENT_H_TYPE)(ip - 2 - base);
|
|
|
|
// Test next position
|
|
ref = base + HashTable[LZ4_HASHVALUE(ip)];
|
|
HashTable[LZ4_HASHVALUE(ip)] = (CURRENT_H_TYPE)(ip - base);
|
|
if ((ref >= ip - MAX_DISTANCE) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }
|
|
|
|
// Prepare next loop
|
|
anchor = ip++;
|
|
forwardH = LZ4_HASHVALUE(ip);
|
|
}
|
|
|
|
_last_literals:
|
|
// Encode Last Literals
|
|
{
|
|
int lastRun = (int)(iend - anchor);
|
|
#ifdef LIMITED_OUTPUT
|
|
if (((char*)op - dest) + lastRun + 1 + ((lastRun+255-RUN_MASK)/255) > (U32)maxOutputSize) return 0; // Check output limit
|
|
#endif
|
|
if (lastRun>=(int)RUN_MASK) { *op++=(RUN_MASK<<ML_BITS); lastRun-=RUN_MASK; for(; lastRun >= 255 ; lastRun-=255) *op++ = 255; *op++ = (BYTE) lastRun; }
|
|
else *op++ = (BYTE)(lastRun<<ML_BITS);
|
|
memcpy(op, anchor, iend - anchor);
|
|
op += iend-anchor;
|
|
}
|
|
|
|
// End
|
|
return (int) (((char*)op)-dest);
|
|
}
|
|
|
|
|
|
|
|
//****************************
|
|
// Clean defines
|
|
//****************************
|
|
|
|
// Required defines
|
|
#undef FUNCTION_NAME
|
|
|
|
// Locally Generated
|
|
#undef HASHLOG
|
|
#undef HASHTABLE_NBCELLS
|
|
#undef LZ4_HASH
|
|
#undef LZ4_HASHVALUE
|
|
#undef CURRENT_H_TYPE
|
|
#undef CURRENTBASE
|
|
|
|
// Optional defines
|
|
#ifdef LIMITED_OUTPUT
|
|
#undef LIMITED_OUTPUT
|
|
#endif
|
|
|
|
#ifdef USE_HEAPMEMORY
|
|
#undef USE_HEAPMEMORY
|
|
#endif
|