zip文档中的例子

/* 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);//只要没有输出空间就说明输出空间已经填满，这同时也说明了输入数据有可能没处理完毕。(deflate返回Z_BUF_ERROR)        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);    }}