mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
242 lines
8.6 KiB
242 lines
8.6 KiB
// SPDX-License-Identifier: BSD-2-Clause |
|
/* |
|
LZ4 - Fast LZ compression algorithm |
|
Copyright (C) 2011-2015, Yann Collet. |
|
|
|
You can contact the author at : |
|
- LZ4 source repository : https://github.com/Cyan4973/lz4 |
|
- LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c |
|
*/ |
|
|
|
|
|
/************************************** |
|
* Reading and writing into memory |
|
**************************************/ |
|
|
|
/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */ |
|
static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd) |
|
{ |
|
BYTE* d = (BYTE*)dstPtr; |
|
const BYTE* s = (const BYTE*)srcPtr; |
|
BYTE* e = (BYTE*)dstEnd; |
|
do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e); |
|
} |
|
|
|
|
|
/************************************** |
|
* Common Constants |
|
**************************************/ |
|
#define MINMATCH 4 |
|
|
|
#define COPYLENGTH 8 |
|
#define LASTLITERALS 5 |
|
#define MFLIMIT (COPYLENGTH+MINMATCH) |
|
static const int LZ4_minLength = (MFLIMIT+1); |
|
|
|
#define KB *(1 <<10) |
|
#define MB *(1 <<20) |
|
#define GB *(1U<<30) |
|
|
|
#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) |
|
|
|
|
|
/************************************** |
|
* Local Structures and types |
|
**************************************/ |
|
typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive; |
|
typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive; |
|
typedef enum { full = 0, partial = 1 } earlyEnd_directive; |
|
|
|
|
|
|
|
/******************************* |
|
* Decompression functions |
|
*******************************/ |
|
/* |
|
* This generic decompression function cover all use cases. |
|
* It shall be instantiated several times, using different sets of directives |
|
* Note that it is essential this generic function is really inlined, |
|
* in order to remove useless branches during compilation optimization. |
|
*/ |
|
FORCE_INLINE int LZ4_decompress_generic( |
|
const char* const source, |
|
char* const dest, |
|
int inputSize, |
|
int outputSize, /* If endOnInput==endOnInputSize, this value is the max size of Output Buffer. */ |
|
|
|
int endOnInput, /* endOnOutputSize, endOnInputSize */ |
|
int partialDecoding, /* full, partial */ |
|
int targetOutputSize, /* only used if partialDecoding==partial */ |
|
int dict, /* noDict, withPrefix64k, usingExtDict */ |
|
const BYTE* const lowPrefix, /* == dest if dict == noDict */ |
|
const BYTE* const dictStart, /* only if dict==usingExtDict */ |
|
const size_t dictSize /* note : = 0 if noDict */ |
|
) |
|
{ |
|
/* Local Variables */ |
|
const BYTE* ip = (const BYTE*) source; |
|
const BYTE* const iend = ip + inputSize; |
|
|
|
BYTE* op = (BYTE*) dest; |
|
BYTE* const oend = op + outputSize; |
|
BYTE* cpy; |
|
BYTE* oexit = op + targetOutputSize; |
|
const BYTE* const lowLimit = lowPrefix - dictSize; |
|
|
|
const BYTE* const dictEnd = (const BYTE*)dictStart + dictSize; |
|
const size_t dec32table[] = {4, 1, 2, 1, 4, 4, 4, 4}; |
|
const size_t dec64table[] = {0, 0, 0, (size_t)-1, 0, 1, 2, 3}; |
|
|
|
const int safeDecode = (endOnInput==endOnInputSize); |
|
const int checkOffset = ((safeDecode) && (dictSize < (int)(64 KB))); |
|
|
|
|
|
/* Special cases */ |
|
if ((partialDecoding) && (oexit> oend-MFLIMIT)) oexit = oend-MFLIMIT; /* targetOutputSize too high => decode everything */ |
|
if ((endOnInput) && (unlikely(outputSize==0))) return ((inputSize==1) && (*ip==0)) ? 0 : -1; /* Empty output buffer */ |
|
if ((!endOnInput) && (unlikely(outputSize==0))) return (*ip==0?1:-1); |
|
|
|
|
|
/* Main Loop */ |
|
while (1) |
|
{ |
|
unsigned token; |
|
size_t length; |
|
const BYTE* match; |
|
|
|
/* get literal length */ |
|
token = *ip++; |
|
if ((length=(token>>ML_BITS)) == RUN_MASK) |
|
{ |
|
unsigned s; |
|
do |
|
{ |
|
s = *ip++; |
|
length += s; |
|
} |
|
while (likely((endOnInput)?ip<iend-RUN_MASK:1) && (s==255)); |
|
if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)(op))) goto _output_error; /* overflow detection */ |
|
if ((safeDecode) && unlikely((size_t)(ip+length)<(size_t)(ip))) goto _output_error; /* overflow detection */ |
|
} |
|
|
|
/* copy literals */ |
|
cpy = op+length; |
|
if (((endOnInput) && ((cpy>(partialDecoding?oexit:oend-MFLIMIT)) || (ip+length>iend-(2+1+LASTLITERALS))) ) |
|
|| ((!endOnInput) && (cpy>oend-COPYLENGTH))) |
|
{ |
|
if (partialDecoding) |
|
{ |
|
if (cpy > oend) goto _output_error; /* Error : write attempt beyond end of output buffer */ |
|
if ((endOnInput) && (ip+length > iend)) goto _output_error; /* Error : read attempt beyond end of input buffer */ |
|
} |
|
else |
|
{ |
|
if ((!endOnInput) && (cpy != oend)) goto _output_error; /* Error : block decoding must stop exactly there */ |
|
if ((endOnInput) && ((ip+length != iend) || (cpy > oend))) goto _output_error; /* Error : input must be consumed */ |
|
} |
|
memcpy(op, ip, length); |
|
ip += length; |
|
op += length; |
|
break; /* Necessarily EOF, due to parsing restrictions */ |
|
} |
|
LZ4_wildCopy(op, ip, cpy); |
|
ip += length; op = cpy; |
|
|
|
/* get offset */ |
|
match = cpy - LZ4_readLE16(ip); ip+=2; |
|
if ((checkOffset) && (unlikely(match < lowLimit))) goto _output_error; /* Error : offset outside destination buffer */ |
|
|
|
/* get matchlength */ |
|
length = token & ML_MASK; |
|
if (length == ML_MASK) |
|
{ |
|
unsigned s; |
|
do |
|
{ |
|
if ((endOnInput) && (ip > iend-LASTLITERALS)) goto _output_error; |
|
s = *ip++; |
|
length += s; |
|
} while (s==255); |
|
if ((safeDecode) && unlikely((size_t)(op+length)<(size_t)op)) goto _output_error; /* overflow detection */ |
|
} |
|
length += MINMATCH; |
|
|
|
/* check external dictionary */ |
|
if ((dict==usingExtDict) && (match < lowPrefix)) |
|
{ |
|
if (unlikely(op+length > oend-LASTLITERALS)) goto _output_error; /* doesn't respect parsing restriction */ |
|
|
|
if (length <= (size_t)(lowPrefix-match)) |
|
{ |
|
/* match can be copied as a single segment from external dictionary */ |
|
match = dictEnd - (lowPrefix-match); |
|
memmove(op, match, length); op += length; |
|
} |
|
else |
|
{ |
|
/* match encompass external dictionary and current segment */ |
|
size_t copySize = (size_t)(lowPrefix-match); |
|
memcpy(op, dictEnd - copySize, copySize); |
|
op += copySize; |
|
copySize = length - copySize; |
|
if (copySize > (size_t)(op-lowPrefix)) /* overlap within current segment */ |
|
{ |
|
BYTE* const endOfMatch = op + copySize; |
|
const BYTE* copyFrom = lowPrefix; |
|
while (op < endOfMatch) *op++ = *copyFrom++; |
|
} |
|
else |
|
{ |
|
memcpy(op, lowPrefix, copySize); |
|
op += copySize; |
|
} |
|
} |
|
continue; |
|
} |
|
|
|
/* copy repeated sequence */ |
|
cpy = op + length; |
|
if (unlikely((op-match)<8)) |
|
{ |
|
const size_t dec64 = dec64table[op-match]; |
|
op[0] = match[0]; |
|
op[1] = match[1]; |
|
op[2] = match[2]; |
|
op[3] = match[3]; |
|
match += dec32table[op-match]; |
|
LZ4_copy4(op+4, match); |
|
op += 8; match -= dec64; |
|
} else { LZ4_copy8(op, match); op+=8; match+=8; } |
|
|
|
if (unlikely(cpy>oend-12)) |
|
{ |
|
if (cpy > oend-LASTLITERALS) goto _output_error; /* Error : last LASTLITERALS bytes must be literals */ |
|
if (op < oend-8) |
|
{ |
|
LZ4_wildCopy(op, match, oend-8); |
|
match += (oend-8) - op; |
|
op = oend-8; |
|
} |
|
while (op<cpy) *op++ = *match++; |
|
} |
|
else |
|
LZ4_wildCopy(op, match, cpy); |
|
op=cpy; /* correction */ |
|
} |
|
|
|
/* end of decoding */ |
|
if (endOnInput) |
|
return (int) (((char*)op)-dest); /* Nb of output bytes decoded */ |
|
else |
|
return (int) (((const char*)ip)-source); /* Nb of input bytes read */ |
|
|
|
/* Overflow error detected */ |
|
_output_error: |
|
return (int) (-(((const char*)ip)-source))-1; |
|
}
|
|
|