这是压缩功能：
static voID Compress2Inc(std::vector<unsigned char> &outBuf,const std::vector<unsigned char> &inBuf){ CLzma2EncHandle enc = Lzma2Enc_Create(&SzAllocForLzma,&SzAllocForLzma2); assert(enc); CLzma2EncProps props; Lzma2EncProps_Init(&props); props.lzmaProps.writeEndMark = 1; // 0 or 1 SRes res = Lzma2Enc_SetProps(enc,&props); assert(res == SZ_OK); unsigned propsSize = LZMA_PROPS_SIZE; outBuf.resize(propsSize); res = Lzma2Enc_WritePropertIEs(enc); //cout << res; //assert(res == SZ_OK && propsSize == LZMA_PROPS_SIZE); VectorInStream inStream = { &VectorInStream_Read,&inBuf,0 }; VectorOutStream outStream = { &VectorOutStream_Write,&outBuf }; res = Lzma2Enc_Encode(enc,(ISeqOutStream*)&outStream,(ISeqInStream*)&inStream,0); assert(res == SZ_OK); Lzma2Enc_Destroy(enc);} 哪里：
static voID *AllocForLzma2(voID *,size_t size) { return Bigalloc(size); }static voID FreeForLzma2(voID *,voID *address) { BigFree(address); }static ISzAlloc SzAllocForLzma2 = { AllocForLzma2,FreeForLzma2 };static voID *AllocForLzma(voID *,size_t size) { return MyAlloc(size); }static voID FreeForLzma(voID *,voID *address) { MyFree(address); }static ISzAlloc SzAllocForLzma = { AllocForLzma,FreeForLzma };typedef struct{ ISeqInStream SeqInStream; const std::vector<unsigned char> *Buf; unsigned BufPos;} VectorInStream;SRes VectorInStream_Read(voID *p,voID *buf,size_t *size){ VectorInStream *ctx = (VectorInStream*)p; *size = min(*size,ctx->Buf->size() - ctx->BufPos); if (*size) memcpy(buf,&(*ctx->Buf)[ctx->BufPos],*size); ctx->BufPos += *size; return SZ_OK;}typedef struct{ ISeqOutStream SeqOutStream; std::vector<unsigned char> *Buf;} VectorOutStream;size_t VectorOutStream_Write(voID *p,const voID *buf,size_t size){ VectorOutStream *ctx = (VectorOutStream*)p; if (size) { unsigned oldSize = ctx->Buf->size(); ctx->Buf->resize(oldSize + size); memcpy(&(*ctx->Buf)[oldSize],buf,size); } return size;} 这是我到目前为止使用uncompression函数,但Lzma2Dec_DecodetoBuf函数返回错误代码1(SZ_ERROR_DATA),我在网上找不到任何关于此的内容.
static voID Uncompress2Inc(std::vector<unsigned char> &outBuf,const std::vector<unsigned char> &inBuf){ CLzma2Dec dec; Lzma2Dec_Construct(&dec); SRes res = Lzma2Dec_Allocate(&dec,outBuf.size(),&SzAllocForLzma); assert(res == SZ_OK); Lzma2Dec_Init(&dec); outBuf.resize(UNCOMpressed_SIZE); unsigned outPos = 0,inPos = LZMA_PROPS_SIZE; ELzmaStatus status; const unsigned BUF_SIZE = 10240; while (outPos < outBuf.size()) { unsigned destLen = min(BUF_SIZE,outBuf.size() - outPos); unsigned srcLen = min(BUF_SIZE,inBuf.size() - inPos); unsigned srcLenold = srcLen,destLenold = destLen; res = Lzma2Dec_DecodetoBuf(&dec,&outBuf[outPos],&destLen,&inBuf[inPos],&srcLen,(outPos + destLen == outBuf.size()) ? LZMA_FINISH_END : LZMA_FINISH_ANY,&status); assert(res == SZ_OK); inPos += srcLen; outPos += destLen; if (status == LZMA_STATUS_FINISHED_WITH_MARK) break; } Lzma2Dec_Free(&dec,&SzAllocForLzma); outBuf.resize(outPos);} 我正在使用从here下载的Visual Studio 2008和LZMA SDK.有人here有完全相同的问题,但我无法使用他的代码……
有没有人使用LZMA SDK成功解压缩LZMA2压缩文件？
请帮忙！
解决方法 一个临时的解决方法是替换SRes res = Lzma2Dec_Allocate(& dec,& SzAllocForLzma);使用SRes res = Lzma2Dec_Allocate(& dec,8,& SzAllocForLzma);在Uncompress2Inc函数中,其中8是幻数…然而,这不是解决问题的正确方法……
第一个错误是Lzma2Enc_WritePropertIEs不返回结果,而是返回属性字节,该字节必须用作Uncompress2Inc函数中Lzma2Dec_Allocate调用的第二个参数.因此,我们用属性字节替换幻数8,一切都按预期工作.
为了实现这一点,必须将5字节标题添加到将在解码功能中提取的编码数据中.这是一个可以在VS2008中运行的示例(不是最完美的代码,但它可以工作……我会稍后回来,当我有时间时,有一个更好的例子)：
voID Lzma2Benchmark::compressChunk(std::vector<unsigned char> &outBuf,const std::vector<unsigned char> &inBuf){ //! \todo This is a temporary workaround,size needs to be added to the m_uncompressedSize = inBuf.size(); std::cout << "Uncompressed size is: " << inBuf.size() << std::endl; DWORD tickCountBeforeCompression = GetTickCount(); CLzma2EncHandle enc = Lzma2Enc_Create(&m_szAllocForLzma,&m_szAllocForLzma2); assert(enc); CLzma2EncProps props; Lzma2EncProps_Init(&props); props.lzmaProps.writeEndMark = 1; // 0 or 1 props.lzmaProps.level = 9; props.lzmaProps.numThreads = 3; //props.numTotalThreads = 2; SRes res = Lzma2Enc_SetProps(enc,&props); assert(res == SZ_OK); // LZMA_PROPS_SIZE == 5 bytes unsigned propsSize = LZMA_PROPS_SIZE; outBuf.resize(propsSize); // I think Lzma2Enc_WritePropertIEs returns the enCoding propertIEs in 1 Byte Byte propertIEs = Lzma2Enc_WritePropertIEs(enc); //! \todo This is a temporary workaround m_propByte = propertIEs; //! \todo Here m_propByte and m_uncompressedSize need to be added to outBuf's 5 byte header so simply add those 2 values to outBuf and start the enCoding from there. BenchmarkUtils::VectorInStream inStream = { &BenchmarkUtils::VectorInStream_Read,0 }; BenchmarkUtils::VectorOutStream outStream = { &BenchmarkUtils::VectorOutStream_Write,0); std::cout << "Compress time is: " << GetTickCount() - tickCountBeforeCompression << " milliseconds.\n"; assert(res == SZ_OK); Lzma2Enc_Destroy(enc); std::cout << "Compressed size is: " << outBuf.size() << std::endl;}voID Lzma2Benchmark::unCompressChunk(std::vector<unsigned char> &outBuf,const std::vector<unsigned char> &inBuf){ DWORD tickCountBeforeUncompression = GetTickCount(); CLzma2Dec dec; Lzma2Dec_Construct(&dec); //! \todo Heere the property size and the uncompressed size need to be extracted from inBuf,which is the compressed data. // The second parameter is a temporary workaround. SRes res = Lzma2Dec_Allocate(&dec,m_propByte/*8*/,&m_szAllocForLzma); assert(res == SZ_OK); Lzma2Dec_Init(&dec); outBuf.resize(m_uncompressedSize); unsigned outPos = 0,inPos = LZMA_PROPS_SIZE; ELzmaStatus status; const unsigned BUF_SIZE = 10240; while(outPos < outBuf.size()) { SizeT destLen = std::min(BUF_SIZE,outBuf.size() - outPos); SizeT srcLen = std::min(BUF_SIZE,inBuf.size() - inPos); SizeT srcLenold = srcLen,&status); assert(res == SZ_OK); inPos += srcLen; outPos += destLen; if(status == LZMA_STATUS_FINISHED_WITH_MARK) { break; } } Lzma2Dec_Free(&dec,&m_szAllocForLzma); outBuf.resize(outPos); std::cout << "Uncompress time is: " << GetTickCount() - tickCountBeforeUncompression << " milliseconds.\n";} 总结 以上是内存溢出为你收集整理的C LZMA SDK：LZMA2压缩文件的解压缩功能全部内容，希望文章能够帮你解决C LZMA SDK：LZMA2压缩文件的解压缩功能所遇到的程序开发问题。
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