信源作业四：LZO算法的压缩与解压技术

于 2017-07-18 22:13:30 发布
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分类专栏： 信源编码作业 文章标签： 压缩 算法

LZO算法简介

LZO算法说明

LZO 是一个用 ANSI C 语言编写的无损压缩库。他能够提供非常快速的压缩和解压功能。解压并不需要内存的支持。即使使用非常大的压缩比例进行缓慢压缩出的数据，依然能够非常快速的解压。LZO 遵循 GNU 的 GPL 使用许可。

介绍

LZO 非常适合进行数据的实时压缩解压处理，这就是说他更关心操作速度，而不是压缩比例。

LZO 使用 ANSI C 语言编写，并且压缩后的数据也被设计为可以跨平台使用的格式。

LZO 拥有如下的特点：

解压速度很快，并且很简单；
解压时不需要内存支持；
压缩的速度还不错；
压缩时只需要 64 KiB 的内存支持；
压缩比例可以根据需要调节，而这并不影响解压的效率，提高压缩比例自然会降低压缩速度；
压缩包含了很多的压缩级别，提供很多选择；
提供只需要 8 KiB 内存支持的压缩级别；
提供线程安全；
提供无损压缩；
LZO提供多重压缩，和复原解压；

LZO算法的编解码器

先下载好lzo-2.10，目录如下所示：

  • 列表内容
    lzo-2.10
    asm
    autoconf
    doc
    examples
    include
    lzotest
    minilzo
    src
    tests
    util

其中，lzoconf.h是LZO数据压缩库的配置，lzodefs.h是对体系结构、操作系统和编译器特定的定义，minilzo.h是迷你LZO实时数据压缩库的子集。minilzo.c是C语言版本的迷你LZO实时数据压缩库的子集，testmini.c是minilzo的测试文件。

一、选择待压缩文件按钮

void CcompressDlg::OnBnClickedButton3()  
{  
    // TODO: 在此添加控件通知处理程序代码  
    CString strFile = _T("");  

    CFileDialog    dlgFile(TRUE, NULL, NULL, OFN_HIDEREADONLY, _T("Describe Files (*.cfg)|*.cfg|All Files (*.*)|*.*||"), NULL);  

    if (dlgFile.DoModal())  
    {  
        strFile = dlgFile.GetPathName();  
    }  

    UpdateData(true);          // 获取数据  
    path = strFile;  
    UpdateData(false);         // 更新数据  
} 
void CcompressDlg::OnBnClickedButton3()  
{  
    // TODO: 在此添加控件通知处理程序代码  
    CString strFile = _T("");  

    CFileDialog    dlgFile(TRUE, NULL, NULL, OFN_HIDEREADONLY, _T("Describe Files (*.cfg)|*.cfg|All Files (*.*)|*.*||"), NULL);  

    if (dlgFile.DoModal())  
    {  
        strFile = dlgFile.GetPathName();  
    }  

    UpdateData(true);          // 获取数据  
    path = strFile;  
    UpdateData(false);         // 更新数据  
}

二、选择解压缩文件按钮

void CcompressDlg::OnBnClickedButton4()  
{  
    // TODO: 在此添加控件通知处理程序代码  
    CString strFile = _T("");  

    CFileDialog    dlgFile(TRUE, NULL, NULL, OFN_HIDEREADONLY, _T("Describe Files (*.cfg)|*.cfg|All Files (*.*)|*.*||"), NULL);  

    if (dlgFile.DoModal())  
    {  
        strFile = dlgFile.GetPathName();  
    }  

    UpdateData(true);          // 获取数据  
    path_decompress = strFile;  
    UpdateData(false);         // 更新数据  
} 
void CcompressDlg::OnBnClickedButton4()  
{  
    // TODO: 在此添加控件通知处理程序代码  
    CString strFile = _T("");  

    CFileDialog    dlgFile(TRUE, NULL, NULL, OFN_HIDEREADONLY, _T("Describe Files (*.cfg)|*.cfg|All Files (*.*)|*.*||"), NULL);  

    if (dlgFile.DoModal())  
    {  
        strFile = dlgFile.GetPathName();  
    }  

    UpdateData(true);          // 获取数据  
    path_decompress = strFile;  
    UpdateData(false);         // 更新数据  
}

三、压缩按钮

void CcompressDlg::OnBnClickedButton1()  
{  
    // TODO: 在此添加控件通知处理程序代码  
#ifdef _UNICODE  
    LONG len1;  
    len1 = WideCharToMultiByte(CP_ACP, 0, path, -1, NULL, 0, NULL, NULL);  
    char *textPath = (char *)malloc(sizeof(char)*(len1 + 1));  
    memset(textPath, 0, len1 + 1);  
    WideCharToMultiByte(CP_ACP, 0, path, -1, textPath, len1 + 1, NULL, NULL);  
#else  
    ptr = new char[str.GetAllocLength() + 1];  
#endif  
    err = fopen_s(&ifp, textPath, "rb");  
    if (err == 0)  
    {  
        printf("Thefile'crt_fopen_s.c'wasopened\n");  
    }  
    fseek(ifp, 0, SEEK_END);  
    unsigned long len = ftell(ifp);  
    myInLen = len;  
    fseek(ifp, 0, SEEK_SET);  
    cpTemp = (char*)malloc(len * sizeof(char));  
    fread(cpTemp, sizeof(char), len, ifp);  
    char *in = cpTemp;  
    char *out = (char*)malloc((len + len / 16 + 64 + 3) * sizeof(char));  

    if (lzo_init() != LZO_E_OK)  
    {  
        printf("internal error - lzo_init() failed !!!\n");  
        printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");  

    }  

    lzo_uint in_len;  
    in_len = len;  
    lzo_memset(in, 0, in_len);  
    lzo_uint out_len;  

    int r;  

    r = lzo1x_1_compress((unsigned char*)in, in_len, (unsigned char*)out, &out_len, wrkmem);  
    char mess[256];  

    if (r == LZO_E_OK)  
    {  
        sprintf_s(mess, sizeof(mess),  "压缩成功！\n\n原文件大小：%lu bytes\n压缩后大小：%lu bytes\n\n解压得到的文件“compress.txt”保存于工程目录下",  
            (unsigned long)in_len, (unsigned long)out_len);  
        MessageBox(CString(mess));  

    }  
    else  
    {  
        /* this should NEVER happen */  
        sprintf_s(mess, sizeof(mess), "压缩失败!\n %d\n", r);  
        MessageBox(CString(mess));  
    }  
    /* check for an incompressible block */  
    if (out_len >= in_len)  
    {  
        sprintf_s(mess, sizeof(mess), "未压缩！\n");  
        MessageBox(CString(mess));  
    }  

    err = fopen_s(&ofp, ".\\compress.txt", "wb");  
    fwrite(out, sizeof(char), out_len, ofp);  

    fclose(ifp);  
    fclose(ofp);  
    free(cpTemp);  
    free(out);  
    free(textPath);  

}
void CcompressDlg::OnBnClickedButton1()  
{  
    // TODO: 在此添加控件通知处理程序代码  
#ifdef _UNICODE  
    LONG len1;  
    len1 = WideCharToMultiByte(CP_ACP, 0, path, -1, NULL, 0, NULL, NULL);  
    char *textPath = (char *)malloc(sizeof(char)*(len1 + 1));  
    memset(textPath, 0, len1 + 1);  
    WideCharToMultiByte(CP_ACP, 0, path, -1, textPath, len1 + 1, NULL, NULL);  
#else  
    ptr = new char[str.GetAllocLength() + 1];  
#endif  
    err = fopen_s(&ifp, textPath, "rb");  
    if (err == 0)  
    {  
        printf("Thefile'crt_fopen_s.c'wasopened\n");  
    }  
    fseek(ifp, 0, SEEK_END);  
    unsigned long len = ftell(ifp);  
    myInLen = len;  
    fseek(ifp, 0, SEEK_SET);  
    cpTemp = (char*)malloc(len * sizeof(char));  
    fread(cpTemp, sizeof(char), len, ifp);  
    char *in = cpTemp;  
    char *out = (char*)malloc((len + len / 16 + 64 + 3) * sizeof(char));  

    if (lzo_init() != LZO_E_OK)  
    {  
        printf("internal error - lzo_init() failed !!!\n");  
        printf("(this usually indicates a compiler bug - try recompiling\nwithout optimizations, and enable '-DLZO_DEBUG' for diagnostics)\n");  

    }  

    lzo_uint in_len;  
    in_len = len;  
    lzo_memset(in, 0, in_len);  
    lzo_uint out_len;  

    int r;  

    r = lzo1x_1_compress((unsigned char*)in, in_len, (unsigned char*)out, &out_len, wrkmem);  
    char mess[256];  

    if (r == LZO_E_OK)  
    {  
        sprintf_s(mess, sizeof(mess),  "压缩成功！\n\n原文件大小：%lu bytes\n压缩后大小：%lu bytes\n\n解压得到的文件“compress.txt”保存于工程目录下",  
            (unsigned long)in_len, (unsigned long)out_len);  
        MessageBox(CString(mess));  

    }  
    else  
    {  
        /* this should NEVER happen */  
        sprintf_s(mess, sizeof(mess), "压缩失败!\n %d\n", r);  
        MessageBox(CString(mess));  
    }  
    /* check for an incompressible block */  
    if (out_len >= in_len)  
    {  
        sprintf_s(mess, sizeof(mess), "未压缩！\n");  
        MessageBox(CString(mess));  
    }  

    err = fopen_s(&ofp, ".\\compress.txt", "wb");  
    fwrite(out, sizeof(char), out_len, ofp);  

    fclose(ifp);  
    fclose(ofp);  
    free(cpTemp);  
    free(out);  
    free(textPath);  

}

四、解压缩按钮

void CcompressDlg::OnBnClickedButton2()  
{  
    // TODO: 在此添加控件通知处理程序代码  
#ifdef _UNICODE  
    LONG len1;  
    len1 = WideCharToMultiByte(CP_ACP, 0, path_decompress, -1, NULL, 0, NULL, NULL);  
    char *textPath = (char *)malloc(sizeof(char)*(len1 + 1));  
    memset(textPath, 0, len1 + 1);  
    WideCharToMultiByte(CP_ACP, 0, path_decompress, -1, textPath, len1 + 1, NULL, NULL);  
#else  
    ptr = new char[str.GetAllocLength() + 1];  
#endif  
    err = fopen_s(&ifp, textPath, "rb");  
    if (err == 0)  
    {  
        printf("Thefile'crt_fopen_s.c'was opened\n");  
    }  
    fseek(ifp, 0, SEEK_END);  
    unsigned long len = ftell(ifp);  
    fseek(ifp, 0, SEEK_SET);  
    cpTemp = (char*)malloc(len * sizeof(char));  
    fread(cpTemp, sizeof(char), len, ifp);  
    char *in = cpTemp;  
    char *out = (char *)malloc(len*100* sizeof(char));  
    memset(out, 0, len * 100 * sizeof(char));  

    int r;  
    lzo_uint new_len;  
    r = lzo1x_decompress((unsigned char*)in, len, (unsigned char*)out, &new_len, NULL);  

    char mess[256];  
    if (r == LZO_E_OK && new_len == myInLen)  
    {  
        sprintf_s(mess, sizeof(mess), "解压成功！\n\n待解压文件大小： %lu bytes\n解压后文件大小： %lu bytes\n\n解压得到的文件“decompress.txt”保存于工程目录下",  
            (unsigned long)len, (unsigned long)new_len);  
        MessageBox(CString(mess));  
    }  
    else  
    {  
        /* this should NEVER happen */  
        sprintf_s(mess, sizeof(mess), "解压失败！ %d\n", r);  
        MessageBox(CString(mess));  
    }  
    err = fopen_s(&ofp, ".\\decompress.txt", "wt+");  
    fwrite(out, sizeof(char), new_len, ofp);  

    fclose(ifp);  
    fclose(ofp);  
    free(cpTemp);  
    free(textPath);  
    free(out);  
}  
void CcompressDlg::OnBnClickedButton2()  
{  
    // TODO: 在此添加控件通知处理程序代码  
#ifdef _UNICODE  
    LONG len1;  
    len1 = WideCharToMultiByte(CP_ACP, 0, path_decompress, -1, NULL, 0, NULL, NULL);  
    char *textPath = (char *)malloc(sizeof(char)*(len1 + 1));  
    memset(textPath, 0, len1 + 1);  
    WideCharToMultiByte(CP_ACP, 0, path_decompress, -1, textPath, len1 + 1, NULL, NULL);  
#else  
    ptr = new char[str.GetAllocLength() + 1];  
#endif  
    err = fopen_s(&ifp, textPath, "rb");  
    if (err == 0)  
    {  
        printf("Thefile'crt_fopen_s.c'was opened\n");  
    }  
    fseek(ifp, 0, SEEK_END);  
    unsigned long len = ftell(ifp);  
    fseek(ifp, 0, SEEK_SET);  
    cpTemp = (char*)malloc(len * sizeof(char));  
    fread(cpTemp, sizeof(char), len, ifp);  
    char *in = cpTemp;  
    char *out = (char *)malloc(len*100* sizeof(char));  
    memset(out, 0, len * 100 * sizeof(char));  

    int r;  
    lzo_uint new_len;  
    r = lzo1x_decompress((unsigned char*)in, len, (unsigned char*)out, &new_len, NULL);  

    char mess[256];  
    if (r == LZO_E_OK && new_len == myInLen)  
    {  
        sprintf_s(mess, sizeof(mess), "解压成功！\n\n待解压文件大小： %lu bytes\n解压后文件大小： %lu bytes\n\n解压得到的文件“decompress.txt”保存于工程目录下",  
            (unsigned long)len, (unsigned long)new_len);  
        MessageBox(CString(mess));  
    }  
    else  
    {  
        /* this should NEVER happen */  
        sprintf_s(mess, sizeof(mess), "解压失败！ %d\n", r);  
        MessageBox(CString(mess));  
    }  
    err = fopen_s(&ofp, ".\\decompress.txt", "wt+");  
    fwrite(out, sizeof(char), new_len, ofp);  

    fclose(ifp);  
    fclose(ofp);  
    free(cpTemp);  
    free(textPath);  
    free(out);  
}

界面效果如图：

这里写图片描述

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