p7zip/C/Lzma86Enc.c

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2017-10-11 12:35:36 +02:00
/* Lzma86Enc.c -- LZMA + x86 (BCJ) Filter Encoder
2016-05-16 : Igor Pavlov : Public domain */
#include "Precomp.h"
#include <string.h>
#include "Lzma86.h"
#include "Alloc.h"
#include "Bra.h"
#include "LzmaEnc.h"
#define SZE_OUT_OVERFLOW SZE_DATA_ERROR
int Lzma86_Encode(Byte *dest, size_t *destLen, const Byte *src, size_t srcLen,
int level, UInt32 dictSize, int filterMode)
{
size_t outSize2 = *destLen;
Byte *filteredStream;
Bool useFilter;
int mainResult = SZ_ERROR_OUTPUT_EOF;
CLzmaEncProps props;
LzmaEncProps_Init(&props);
props.level = level;
props.dictSize = dictSize;
*destLen = 0;
if (outSize2 < LZMA86_HEADER_SIZE)
return SZ_ERROR_OUTPUT_EOF;
{
int i;
UInt64 t = srcLen;
for (i = 0; i < 8; i++, t >>= 8)
dest[LZMA86_SIZE_OFFSET + i] = (Byte)t;
}
filteredStream = 0;
useFilter = (filterMode != SZ_FILTER_NO);
if (useFilter)
{
if (srcLen != 0)
{
filteredStream = (Byte *)MyAlloc(srcLen);
if (filteredStream == 0)
return SZ_ERROR_MEM;
memcpy(filteredStream, src, srcLen);
}
{
UInt32 x86State;
x86_Convert_Init(x86State);
x86_Convert(filteredStream, srcLen, 0, &x86State, 1);
}
}
{
size_t minSize = 0;
Bool bestIsFiltered = False;
/* passes for SZ_FILTER_AUTO:
0 - BCJ + LZMA
1 - LZMA
2 - BCJ + LZMA agaian, if pass 0 (BCJ + LZMA) is better.
*/
int numPasses = (filterMode == SZ_FILTER_AUTO) ? 3 : 1;
int i;
for (i = 0; i < numPasses; i++)
{
size_t outSizeProcessed = outSize2 - LZMA86_HEADER_SIZE;
size_t outPropsSize = 5;
SRes curRes;
Bool curModeIsFiltered = (numPasses > 1 && i == numPasses - 1);
if (curModeIsFiltered && !bestIsFiltered)
break;
if (useFilter && i == 0)
curModeIsFiltered = True;
curRes = LzmaEncode(dest + LZMA86_HEADER_SIZE, &outSizeProcessed,
curModeIsFiltered ? filteredStream : src, srcLen,
&props, dest + 1, &outPropsSize, 0,
NULL, &g_Alloc, &g_Alloc);
if (curRes != SZ_ERROR_OUTPUT_EOF)
{
if (curRes != SZ_OK)
{
mainResult = curRes;
break;
}
if (outSizeProcessed <= minSize || mainResult != SZ_OK)
{
minSize = outSizeProcessed;
bestIsFiltered = curModeIsFiltered;
mainResult = SZ_OK;
}
}
}
dest[0] = (Byte)(bestIsFiltered ? 1 : 0);
*destLen = LZMA86_HEADER_SIZE + minSize;
}
if (useFilter)
MyFree(filteredStream);
return mainResult;
}