gzip flate实现？该如何解决

gzip flate实现？
下面的代码是抄来的然后做了些修改，压缩出来的数据，用gzip解压时，提示not in gzip format，请问有谁知道我哪弄错了吗？对这个不了解，也不知道参考什么。

C/C++ code

int gzcompress(Bytef *zdata, uLong *nzdata,Bytef *data, uLong ndata)
{
    gz_header_s gz_header;
    z_stream c_stream;
    int err = 0;
 
    if(data && ndata > 0)
    {
        c_stream.zalloc = (alloc_func)0;
        c_stream.zfree = (free_func)0;
        c_stream.opaque = (voidpf)0;
        if(deflateInit2(&c_stream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,  
                    -MAX_WBITS, 8, Z_DEFAULT_STRATEGY) != Z_OK) return -1;
        c_stream.next_in  = data;
        c_stream.avail_in  = ndata;
        c_stream.next_out = zdata;
        c_stream.avail_out  = *nzdata;
        
        gz_header.text = 0;
        gz_header.time = time(NULL);
        gz_header.xflags = 0;
        gz_header.os = 3;
        gz_header.extra = Z_NULL;
        gz_header.extra_len = 0;
        gz_header.extra_max = 0;
        gz_header.name = Z_NULL;
        gz_header.name_max = 0;
        gz_header.comment = Z_NULL;
        gz_header.comm_max = 0;
        gz_header.hcrc = 1;
        gz_header.done = 1;
        deflateSetHeader(&c_stream, &gz_header);
        
        while (c_stream.avail_in != 0 && c_stream.total_out < *nzdata)  
        {
            if(deflate(&c_stream, Z_NO_FLUSH) != Z_OK) return -1;
        }
        if(c_stream.avail_in != 0) return c_stream.avail_in;
        for (;;) {
            if((err = deflate(&c_stream, Z_FINISH)) == Z_STREAM_END) break;
            if(err != Z_OK) return -1;
        }
        if(deflateEnd(&c_stream) != Z_OK) return -1;
        *nzdata = c_stream.total_out;
        return 0;
    }
    return -1;
} 

C/C++ code

/*

00480 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

00481                                      int  level,

00482                                      int  method,

00483                                      int  windowBits,

00484                                      int  memLevel,

00485                                      int  strategy));

00486

00487      This is another version of deflateInit with more compression options. The

00488    fields next_in, zalloc, zfree and opaque must be initialized before by

00489    the caller.

00490

00491      The method parameter is the compression method. It must be Z_DEFLATED in

00492    this version of the library.

00493

00494      The windowBits parameter is the base two logarithm of the window size

00495    (the size of the history buffer). It should be in the range 8..15 for this

00496    version of the library. Larger values of this parameter result in better

00497    compression at the expense of memory usage. The default value is 15 if

00498    deflateInit is used instead.

00499

00500      windowBits can also be -8..-15 for raw deflate. In this case, -windowBits

00501    determines the window size. deflate() will then generate raw deflate data

00502    with no zlib header or trailer, and will not compute an adler32 check value.

00503

00504      windowBits can also be greater than 15 for optional gzip encoding. Add

00505    16 to windowBits to write a simple gzip header and trailer around the

00506    compressed data instead of a zlib wrapper. The gzip header will have no

00507    file name, no extra data, no comment, no modification time (set to zero),

00508    no header crc, and the operating system will be set to 255 (unknown).  If a

00509    gzip stream is being written, strm->adler is a crc32 instead of an adler32.

00510

00511      The memLevel parameter specifies how much memory should be allocated

00512    for the internal compression state. memLevel=1 uses minimum memory but

00513    is slow and reduces compression ratio; mem