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/* 7zExtract.c -- Extracting from 7z archive
2008-11-23 : Igor Pavlov : Public domain */
#include "../../7zCrc.h"
#include "7zDecode.h"
#include "7zExtract.h"
SRes SzAr_Extract(
const CSzArEx *p,
ILookInStream *inStream,
UInt32 fileIndex,
UInt32 *blockIndex,
Byte **outBuffer,
size_t *outBufferSize,
size_t *offset,
size_t *outSizeProcessed,
ISzAlloc *allocMain,
ISzAlloc *allocTemp)
{
UInt32 folderIndex = p->FileIndexToFolderIndexMap[fileIndex];
SRes res = SZ_OK;
*offset = 0;
*outSizeProcessed = 0;
if (folderIndex == (UInt32)-1)
{
IAlloc_Free(allocMain, *outBuffer);
*blockIndex = folderIndex;
*outBuffer = 0;
*outBufferSize = 0;
return SZ_OK;
}
if (*outBuffer == 0 || *blockIndex != folderIndex)
{
CSzFolder *folder = p->db.Folders + folderIndex;
UInt64 unpackSizeSpec = SzFolder_GetUnpackSize(folder);
size_t unpackSize = (size_t)unpackSizeSpec;
UInt64 startOffset = SzArEx_GetFolderStreamPos(p, folderIndex, 0);
if (unpackSize != unpackSizeSpec)
return SZ_ERROR_MEM;
*blockIndex = folderIndex;
IAlloc_Free(allocMain, *outBuffer);
*outBuffer = 0;
RINOK(LookInStream_SeekTo(inStream, startOffset));
if (res == SZ_OK)
{
*outBufferSize = unpackSize;
if (unpackSize != 0)
{
*outBuffer = (Byte *)IAlloc_Alloc(allocMain, unpackSize);
if (*outBuffer == 0)
res = SZ_ERROR_MEM;
}
if (res == SZ_OK)
{
res = SzDecode(p->db.PackSizes +
p->FolderStartPackStreamIndex[folderIndex], folder,
inStream, startOffset,
*outBuffer, unpackSize, allocTemp);
if (res == SZ_OK)
{
if (folder->UnpackCRCDefined)
{
if (CrcCalc(*outBuffer, unpackSize) != folder->UnpackCRC)
res = SZ_ERROR_CRC;
}
}
}
}
}
if (res == SZ_OK)
{
UInt32 i;
CSzFileItem *fileItem = p->db.Files + fileIndex;
*offset = 0;
for (i = p->FolderStartFileIndex[folderIndex]; i < fileIndex; i++)
*offset += (UInt32)p->db.Files[i].Size;
*outSizeProcessed = (size_t)fileItem->Size;
if (*offset + *outSizeProcessed > *outBufferSize)
return SZ_ERROR_FAIL;
{
if (fileItem->FileCRCDefined)
{
if (CrcCalc(*outBuffer + *offset, *outSizeProcessed) != fileItem->FileCRC)
res = SZ_ERROR_CRC;
}
}
}
return res;
}
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