ssize_t gunzip(void *dst, size_t dstlen, uint8_t *src, size_t srclen)
{
    z_stream s;
    ssize_t dstbytes;
    int r, i, flags;

    /* skip header */
    i = 10;
    flags = src[3];
    if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
        puts ("Error: Bad gzipped data\n");
        return -1;
    }
    if ((flags & EXTRA_FIELD) != 0)
        i = 12 + src[10] + (src[11] << 8);
    if ((flags & ORIG_NAME) != 0)
        while (src[i++] != 0)
            ;
    if ((flags & COMMENT) != 0)
        while (src[i++] != 0)
            ;
    if ((flags & HEAD_CRC) != 0)
        i += 2;
    if (i >= srclen) {
        puts ("Error: gunzip out of data in header\n");
        return -1;
    }

    s.zalloc = zalloc;
    s.zfree = zfree;

    r = inflateInit2(&s, -MAX_WBITS);
    if (r != Z_OK) {
        printf ("Error: inflateInit2() returned %d\n", r);
        return (-1);
    }
    s.next_in = src + i;
    s.avail_in = srclen - i;
    s.next_out = dst;
    s.avail_out = dstlen;
    r = inflate(&s, Z_FINISH);
    if (r != Z_OK && r != Z_STREAM_END) {
        printf ("Error: inflate() returned %d\n", r);
        return -1;
    }
    dstbytes = s.next_out - (unsigned char *) dst;
    inflateEnd(&s);

    return dstbytes;
}
Unknown