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