C语言压缩/解压缩

一、简介

Lzlib 压缩库提供了在内存中的 LZMA 压缩和解压算法功能，包括对数据进行完整性检查。压缩格式是 lzip

参考：

http://blog.csdn.net/damenhanter/article/details/30757685

二、安装

http://www.educity.cn/linux/1577732.html

三、实例

参考：

http://blog.csdn.net/turingo/article/details/8148264

示例1：compression.c

#include <stdlib.h>
#include <stdio.h>
#include <zlib.h>

int main(int argc, char* argv[])
{
    FILE* file;
    uLong flen;
    unsigned char* fbuf = NULL;
    uLong clen;
    unsigned char* cbuf = NULL;

    /* 通过命令行参数将srcfile文件的数据压缩后存放到dstfile文件中 */
    if(argc < 3)
    {
        printf("Usage: zcdemo srcfile dstfile\n");
        return -1;
    }

    if((file = fopen(argv[1], "rb")) == NULL)
    {
        printf("Can\'t open %s!\n", argv[1]);
        return -1;
    }
    /* 装载源文件数据到缓冲区 */
    fseek(file, 0L, SEEK_END); /* 跳到文件末尾 */
    flen = ftell(file);  /* 获取文件长度 */
    fseek(file, 0L, SEEK_SET);
    if((fbuf = (unsigned char*)malloc(sizeof(unsigned char) * flen)) == NULL)
    {
        printf("No enough memory!\n");
        fclose(file);
        return -1;
    }
    fread(fbuf, sizeof(unsigned char), flen, file);
    /* 压缩数据 */
    clen = compressBound(flen);
    if((cbuf = (unsigned char*)malloc(sizeof(unsigned char) * clen)) == NULL)
    {
        printf("No enough memory!\n");
        fclose(file);
        return -1;
    }
    if(compress(cbuf, &clen, fbuf, flen) != Z_OK)
    {
        printf("Compress %s failed!\n", argv[1]);
        return -1;
    }
    fclose(file);

    if((file = fopen(argv[2], "wb")) == NULL)
    {
        printf("Can\'t create %s!\n", argv[2]);
        return -1;
    }
    /* 保存压缩后的数据到目标文件 */
    fwrite(&flen, sizeof(uLong), 1, file); /* 写入源文件长度 */
    fwrite(&clen, sizeof(uLong), 1, file); /* 写入目标数据长度 */
    fwrite(cbuf, sizeof(unsigned char), clen, file);
    fclose(file);

    free(fbuf);
    free(cbuf);

    return 0;
}

decompression.c

#include <stdlib.h>
#include <stdio.h>
#include <zlib.h>

int main(int argc, char* argv[])
{
    FILE* file;
    uLong flen;
    unsigned char* fbuf = NULL;
    uLong ulen;
    unsigned char* ubuf = NULL;

    /* 通过命令行参数将srcfile文件的数据解压缩后存放到dstfile文件中 */
    if(argc < 3)
    {
        printf("Usage: zudemo srcfile dstfile\n");
        return -1;
    }

    if((file = fopen(argv[1], "rb")) == NULL)
    {
        printf("Can\'t open %s!\n", argv[1]);
        return -1;
    }
    /* 装载源文件数据到缓冲区 */
    fread(&ulen, sizeof(uLong), 1, file);    /* 获取缓冲区大小 */
    fread(&flen, sizeof(uLong), 1, file);    /* 获取数据流大小 */
    if((fbuf = (unsigned char*)malloc(sizeof(unsigned char) * flen)) == NULL)
    {
        printf("No enough memory!\n");
        fclose(file);
        return -1;
    }
    fread(fbuf, sizeof(unsigned char), flen, file);
    /* 解压缩数据 */
    if((ubuf = (unsigned char*)malloc(sizeof(unsigned char) * ulen)) == NULL)
    {
        printf("No enough memory!\n");
        fclose(file);
        return -1;
    }
    if(uncompress(ubuf, &ulen, fbuf, flen) != Z_OK)
    {
        printf("Uncompress %s failed!\n", argv[1]);
        return -1;
    }
    fclose(file);

    if((file = fopen(argv[2], "wb")) == NULL)
    {
        printf("Can\'t create %s!\n", argv[2]);
        return -1;
    }
    /* 保存解压缩后的数据到目标文件 */
    fwrite(ubuf, sizeof(unsigned char), ulen, file);
    fclose(file);

    free(fbuf);
    free(ubuf);

    return 0;
}

编译

gcc -g -o compression compression.c -lz
gcc -g -o decompression decompression.c -lz

运行

示例2：

参考：

http://blog.csdn.net/yoki2009/article/details/4291215
http://www.cppblog.com/woaidongmao/archive/2009/09/07/95495.html

/* zpipe.c: example of proper use of zlib's inflate() and deflate()
   Not copyrighted -- provided to the public domain
   Version 1.2  9 November 2004  Mark Adler */

/* Version history:
   1.0  30 Oct 2004  First version
   1.1   8 Nov 2004  Add void casting for unused return values
                     Use switch statement for inflate() return values
   1.2   9 Nov 2004  Add assertions to document zlib guarantees
   1.3   6 Apr 2005  Remove incorrect assertion in inf()
 */

#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "zlib.h"

#define CHUNK 16384

/* Compress from file source to file dest until EOF on source.
   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
   allocated for processing, Z_STREAM_ERROR if an invalid compression
   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
   version of the library linked do not match, or Z_ERRNO if there is
   an error reading or writing the files. */
int def(FILE *source, FILE *dest, int level)
{
    int ret, flush;
    unsigned have;
    z_stream strm;
    char in[CHUNK];
    char out[CHUNK];

    /* allocate deflate state */
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    ret = deflateInit(&strm, level);
    if (ret != Z_OK)
        return ret;

    /* compress until end of file */
    do {
        strm.avail_in = fread(in, 1, CHUNK, source);
        if (ferror(source)) {
            (void)deflateEnd(&strm);
            return Z_ERRNO;
        }
        flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
        strm.next_in = in;

        /* run deflate() on input until output buffer not full, finish
           compression if all of source has been read in */
        do {
            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = deflate(&strm, flush);    /* no bad return value */
            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
            have = CHUNK - strm.avail_out;
            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
                (void)deflateEnd(&strm);
                return Z_ERRNO;
            }
        } while (strm.avail_out == 0);
        assert(strm.avail_in == 0);     /* all input will be used */

        /* done when last data in file processed */
    } while (flush != Z_FINISH);
    assert(ret == Z_STREAM_END);        /* stream will be complete */

    /* clean up and return */
    (void)deflateEnd(&strm);
    return Z_OK;
}

/* Decompress from file source to file dest until stream ends or EOF.
   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
   allocated for processing, Z_DATA_ERROR if the deflate data is
   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
   the version of the library linked do not match, or Z_ERRNO if there
   is an error reading or writing the files. */
int inf(FILE *source, FILE *dest)
{
    int ret;
    unsigned have;
    z_stream strm;
    char in[CHUNK];
    char out[CHUNK];

    /* allocate inflate state */
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = 0;
    strm.next_in = Z_NULL;
    ret = inflateInit(&strm);
    if (ret != Z_OK)
        return ret;

    /* decompress until deflate stream ends or end of file */
    do {
        strm.avail_in = fread(in, 1, CHUNK, source);
        if (ferror(source)) {
            (void)inflateEnd(&strm);
            return Z_ERRNO;
        }
        if (strm.avail_in == 0)
            break;
        strm.next_in = in;

        /* run inflate() on input until output buffer not full */
        do {
            strm.avail_out = CHUNK;
            strm.next_out = out;
            ret = inflate(&strm, Z_NO_FLUSH);
            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
            switch (ret) {
            case Z_NEED_DICT:
                ret = Z_DATA_ERROR;     /* and fall through */
            case Z_DATA_ERROR:
            case Z_MEM_ERROR:
                (void)inflateEnd(&strm);
                return ret;
            }
            have = CHUNK - strm.avail_out;
            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
                (void)inflateEnd(&strm);
                return Z_ERRNO;
            }
        } while (strm.avail_out == 0);

        /* done when inflate() says it's done */
    } while (ret != Z_STREAM_END);

    /* clean up and return */
    (void)inflateEnd(&strm);
    return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}

/* report a zlib or i/o error */
void zerr(int ret)
{
    fputs("zpipe: ", stderr);
    switch (ret) {
    case Z_ERRNO:
        if (ferror(stdin))
            fputs("error reading stdin\n", stderr);
        if (ferror(stdout))
            fputs("error writing stdout\n", stderr);
        break;
    case Z_STREAM_ERROR:
        fputs("invalid compression level\n", stderr);
        break;
    case Z_DATA_ERROR:
        fputs("invalid or incomplete deflate data\n", stderr);
        break;
    case Z_MEM_ERROR:
        fputs("out of memory\n", stderr);
        break;
    case Z_VERSION_ERROR:
        fputs("zlib version mismatch!\n", stderr);
    }
}

/* compress or decompress from stdin to stdout */
int main(int argc, char **argv)
{
    int ret;
    FILE *filein, *fileout;

    if((filein = fopen(argv[1], "rb")) == NULL)
    {
        printf("Can\'t open %s!\n", argv[1]);
        return -1;
    }

    if((fileout = fopen(argv[2], "wb")) == NULL)
    {
        printf("Can\'t open %s!\n", argv[1]);
        return -1;
    }

    /* do compression if no arguments */
    if (argc == 3) {
        ret = def(filein, fileout, Z_DEFAULT_COMPRESSION);
        if (ret != Z_OK)
            zerr(ret);
        return ret;
    }

    /* do decompression if -d specified */
    else if (argc == 4 && strcmp(argv[3], "-d") == 0) {
        ret = inf(filein, fileout);
        if (ret != Z_OK)
            zerr(ret);
        return ret;
    }

    /* otherwise, report usage */
    else {
        fputs("zpipe usage: zpipe (source) (dest) [-d] \n", stderr);
        return 1;
    }
}

编译

gcc -g -o zpipe zpipe.c -lz

运行