c - 使用 zlib 使用 zpipe.c 示例创建 gzip 文件

Question

全部，

我只是想让 zpipe 演示使用 dev-c++ 工作，其中我导入了所有 zlib 代码并使用 zpipe.c 作为示例。一切都编译并运行。如果我尝试使用注释掉的对 deflateInit2 的调用创建一个 gzip 文件，它会创建现在错误，但在使用 7zip 解压缩时已损坏。如果我使用标准的 zlib 头文件来创建文件，当我使用相应的调用来膨胀时，它会返回 -3/Z_DATA_ERROR 指示我的默认数据已损坏。一切都指向定义中的错误，但它几乎正是示例。

有任何想法吗？？非常感谢!

int main(int argc, char **argv)
{
     int ret;
     FILE *source;
     FILE *zip;
     FILE *zipped;
     FILE *back;

     source = fopen ("C:\\Users\\schmoudm\\Pictures\\caela.jpg", "r");
     zip = fopen ("C:\\Core\\RD\\test.gz", "w");

     printf ("calling def \n");
     ret = def(source, zip, Z_DEFAULT_COMPRESSION);
     printf("def return: %i \n", ret);
     fclose(source);
     fclose(zip);

     if (ret == 0) {
        printf ("setting up inf \n");
        zipped = fopen ("C:\\Core\\RD\\test.gz", "r"); 
        back = fopen ("C:\\Core\\RD\\zlibout.txt", "w"); 
        printf ("calling inf \n");
        ret = inf(zipped, back); 
        printf("inf return: %i \n", ret);  
        zerr(ret);
     }

    fclose(source);
    fclose(zip);

    printf("DONE!");
    system("PAUSE");
    return 0;
}

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, Z_DEFAULT_COMPRESSION);
    //ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, (15+16), 8,       Z_DEFAULT_STRATEGY);
    if (ret != Z_OK)
        return ret;

    /* compress until end of file */
    do {
        strm.avail_in = fread(in, 1, CHUNK, source);
        printf("available in: %u \n", strm.avail_in);  
        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;
}

Answer 1

but its pretty much exactly the example.

唉，您遗漏了 zpipe.c 中的关键部分.

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
#  include <fcntl.h>
#  include <io.h>
#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
#else
#  define SET_BINARY_MODE(file)
#endif

和

/* avoid end-of-line conversions */
SET_BINARY_MODE(stdin);
SET_BINARY_MODE(stdout);

所以在你的代码中你需要做 SET_BINARY_MODE(source)和 SET_BINARY_MODE(zip) .

或者您需要使用 "b"两个选项 fopen()的。