小试zlib

zlib1.2.3需要unistd.h、getopt.h两个头文件，我就奇怪了，我的vc6/7里面没有这两个头文件，只好从MinGW借用一下。竟然编译通过了。

然后改了一下那个zpipe.c例子，如下：

// zipTest.cpp : Defines the entry point for the console application.
//

#include “stdafx.h”

/* 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 “E:/zlib123/include/zlib.h”
#pragma comment(lib, “zlib.lib”)
#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;
    unsigned char in[CHUNK];
    unsigned 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;
    unsigned char in[CHUNK];
    unsigned 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;

 // compress:  data.txt should exist
 FILE* pfIn = fopen(“data.txt”, “r”);
 FILE* pfOut = fopen(“data.txt.z”, “w+b”);
 if(pfIn == NULL)
 {

  fputs(“can’t open file/n”, stderr);
  return 0;
 }
 ret = def(pfIn, pfOut, Z_DEFAULT_COMPRESSION);
 if (ret != Z_OK)
  zerr(ret);
 
 fclose(pfIn);
 fclose(pfOut);
 
 return ret;
 // decompress: data.txt.z should exist
 /*
 FILE* pfIn = fopen(“data.txt.z”, “rb”);
 FILE* pfOut = fopen(“data3.txt”, “w+”);
 if(pfIn == NULL)
 {

 fputs(“can’t open file/n”, stderr);
 return 0;k
 }
 ret = inf(pfIn, pfOut);
 if (ret != Z_OK)
 zerr(ret);
 
 fclose(pfIn);
 fclose(pfOut);
  
    return ret;
 */
}