C语言压缩/解压缩
2024-08-30 07:34:27
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：
二、安装
三、实例
参考：
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：
/* 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
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