Lzma(7-zip)

在C目录中有算法文件,进入Util\LzmaLib目录,编译生成LIB库,导出了以下两函数,LzmaCompress 为压缩函数,LzmaUncompress 为解压缩函数。

MY_STDAPI LzmaCompress(unsigned char *dest, size_t *destLen, const unsigned char *src, size_t srcLen,
  unsigned char *outProps, size_t *outPropsSize,
  int level,     
  unsigned dictSize, 
  int lc,       
  int lp,       
  int pb,       
  int fb,       
  int numThreads
  );

MY_STDAPI LzmaUncompress(unsigned char *dest, size_t *destLen, const unsigned char *src, SizeT *srcLen,
  const unsigned char *props, size_t propsSize);

导入Types.h 和 Lzmalib.h 到工程中。

代码如下:

#include "stdafx.h"
#include "LzmaLib.h"

#pragma comment(lib,"lzma.lib")

int _tmain(int argc, _TCHAR* argv[])
{
    FILE* pFile = _tfopen(_T("file.dat"), _T("rb"));

    if (pFile == NULL)
    {
        _ftprintf(stderr, _T("Error to Open the file!"));
        return  - 1;
    }

    fseek(pFile, 0, SEEK_END);
    size_t srcLen = ftell(pFile);
    rewind(pFile);
    size_t destLen = srcLen * 2;
    unsigned char* psrcRead = new unsigned char[srcLen]; //原始文件数据
    unsigned char* pDecomress = new unsigned char[srcLen]; //存放解压缩数据
    unsigned char* pLzma = new unsigned char[destLen]; //存放压缩数据

    fread(psrcRead, sizeof(char), srcLen, pFile);

    unsigned char prop[5] = 
    {
        0
    };
    size_t sizeProp = 5;

    if (SZ_OK != LzmaCompress(pLzma, &destLen, psrcRead, srcLen, prop,
        &sizeProp, 9, (1 << 24), 3, 0, 2, 32, 2))
    {
        //出错了
        _ftprintf(stderr, _T("压缩时出错!"));
        delete [] psrcRead;
        delete [] pDecomress;
        delete [] pLzma;
        fclose(pFile);
        return  - 1;
    }

    FILE* pCompressFile = _tfopen(_T("compress.dat"), _T("wb")); 
    //写入压缩后的数据
    if (pCompressFile == NULL)
    {
        _ftprintf(stderr, _T("创建文件出错!"));
        delete [] psrcRead;
        delete [] pDecomress;
        delete [] pLzma;
        fclose(pFile);
        return  - 1;
    }
    fwrite(pLzma, sizeof(char), destLen, pCompressFile);
    fclose(pCompressFile);

    FILE* pDecompressFile = _tfopen(_T("decompress.dat"), _T("wb")); 
    //写入解压缩数据
    if (pDecompressFile == NULL)
    {
        _ftprintf(stderr, _T("写入数据出错!"));
        delete [] psrcRead;
        delete [] pDecomress;
        delete [] pLzma;
        fclose(pFile);
        return  - 1;
    }

    //注意:解压缩时props参数要使用压缩时生成的outProps,这样才能正常解压缩
    if (SZ_OK != LzmaUncompress(pDecomress, &srcLen, pLzma, &destLen, prop, 5))
    {
        delete [] psrcRead;
        delete [] pDecomress;
        delete [] pLzma;

        fclose(pDecompressFile);
        fclose(pFile);
        return  - 1;
    }

    fwrite(pDecomress, sizeof(char), srcLen, pDecompressFile);

    delete [] psrcRead;
    delete [] pDecomress;
    delete [] pLzma;

    fclose(pDecompressFile);
    fclose(pFile);

    return 0;
}


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