C language compression/decompression, C language Decompression

C language compression/decompression, C language Decompression

I. Introduction

The Lzlib compression library provides LZMA compression and decompression algorithm functions in the memory, including data integrity check. The compression format is lzip.

 

Refer:

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

 

Ii. Installation

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

 

Iii. Instances

Refer:

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

 

Example 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; /* compress the data in the srcfile file using the command line parameters and store the data in the dstfile */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;}/* load source file data to the buffer */fseek (file, 0L, SEEK_END ); /* jump to the end of the file */flen = ftell (file);/* get the file length */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 ); /* compressed data */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;}/* Save the compressed data to the target file */fwrite (& flen, sizeof (uLong), 1, file);/* write source file length */fwrite (& clen, sizeof (uLong), 1, file);/* write target data length */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; /* decompress the data in the srcfile file using the command line parameters and store the data in the dstfile */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;}/* load source file data to the buffer */fread (& ulen, sizeof (uLong), 1, file ); /* obtain the buffer size */fread (& flen, sizeof (uLong), 1, file);/* obtain the data stream size */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 ); /* extract data */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;}/* Save the decompressed data to the target file */fwrite (ubuf, sizeof (unsigned char), ulen, file); fclose (file); free (fbuf); free (ubuf); return 0 ;}

Compile

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

Run

 

Example 2:

Refer:

http://blog.csdn.net/yoki2009/article/details/4291215http://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;    }}

Compile

gcc -g -o zpipe zpipe.c -lz

Run