return FALSE;}static int ZeroDataBlock = FALSE;static intGetDataBlock(MG_RWops *src, unsigned char *buf){    unsigned char count;    if (!ReadOK(src, &count, 1))        return -1;    ZeroDataBlock = count == 0;    if ((count != 0) && (!ReadOK(src, buf, count)))        return -1;    return count;}static intGetCode(MG_RWops *src, int code_size, int flag){    static unsigned char buf[280];    static int curbit, lastbit, done, last_byte;    int i, j, ret;    unsigned char count;    if (flag) {        curbit = 0;        lastbit = 0;        done = FALSE;        return 0;    }    if ((curbit + code_size) >= lastbit) {        if (done) {            if (curbit >= lastbit)#ifdef _DEBUG                fprintf (stderr,"__mg_load_gif: bad decode\n");#endif            return -1;        }        buf[0] = buf[last_byte - 2];        buf[1] = buf[last_byte - 1];        if ((count = GetDataBlock(src, &buf[2])) == 0)            done = TRUE;        last_byte = 2 + count;        curbit = (curbit - lastbit) + 16;        lastbit = (2 + count) * 8;    }    ret = 0;    for (i = curbit, j = 0; j < code_size; ++i, ++j)        ret |= ((buf[i / 8] & (1 << (i % 8))) != 0) << j;    curbit += code_size;    return ret;}static intLWZReadByte(MG_RWops *src, int flag, int input_code_size){    int code, incode;    register int i;    static int fresh = FALSE;    static int code_size, set_code_size;    static int max_code, max_code_size;    static int firstcode, oldcode;    static int clear_code, end_code;    static int table[2][(1 << MAX_LWZ_BITS)];    static int stack[(1 << (MAX_LWZ_BITS)) * 2], *sp;    if (flag) {        set_code_size = input_code_size;        code_size = set_code_size + 1;        clear_code = 1 << set_code_size;        end_code = clear_code + 1;        max_code_size = 2 * clear_code;        max_code = clear_code + 2;        GetCode(src, 0, TRUE);        fresh = TRUE;        for (i = 0; i < clear_code; ++i) {            table[0][i] = 0;            table[1][i] = i;        }        for (; i < (1 << MAX_LWZ_BITS); ++i)            table[0][i] = table[1][0] = 0;        sp = stack;        return 0;    } else if (fresh) {        fresh = FALSE;        do {            firstcode = oldcode = GetCode(src, code_size, FALSE);        } while (firstcode == clear_code);        return firstcode;    }    if (sp > stack)        return *--sp;    while ((code = GetCode(src, code_size, FALSE)) >= 0) {        if (code == clear_code) {            for (i = 0; i < clear_code; ++i) {                table[0][i] = 0;                table[1][i] = i;            }            for (; i < (1 << MAX_LWZ_BITS); ++i)                table[0][i] = table[1][i] = 0;            code_size = set_code_size + 1;            max_code_size = 2 * clear_code;            max_code = clear_code + 2;            sp = stack;            firstcode = oldcode = GetCode(src, code_size, FALSE);            return firstcode;        } else if (code == end_code) {            int count;            unsigned char buf[260];            if (ZeroDataBlock)                return -2;            while ((count = GetDataBlock(src, buf)) > 0);            if (count != 0) {                /*                 * fprintf (stderr,"missing EOD in data stream (common occurence)");                 */            }            return -2;        }        incode = code;        if (code >= max_code) {            *sp++ = firstcode;            code = oldcode;        }        while (code >= clear_code) {            *sp++ = table[1][code];            if (code == table[0][code]) {                fprintf (stderr, "__mg_load_gif: circular table entry\n");                return -1;            }            code = table[0][code];        }        *sp++ = firstcode = table[1][code];        if ((code = max_code) < (1 << MAX_LWZ_BITS)) {            table[0][code] = oldcode;            table[1][code] = firstcode;            ++max_code;            if ((max_code >= max_code_size) &&                (max_code_size < (1 << MAX_LWZ_BITS))) {                max_code_size *= 2;                ++code_size;            }        }        oldcode = incode;        if (sp > stack)            return *--sp;    }    return code;}static intReadImage(MG_RWops* src, MYBITMAP* bmp, RGB* pal, int len, int height, int cmapSize,          unsigned char cmap[3][MAXCOLORMAPSIZE],          int gray, int interlace, int ignore){    unsigned char c;    int i, v;    int xpos = 0, ypos = 0, pass = 0;    /*     *        Initialize the compression routines     */    if (!ReadOK(src, &c, 1)) {        fprintf (stderr,"__mg_load_gif: EOF on image data\n");        return 0;    }    if (LWZReadByte(src, TRUE, c) < 0) {        fprintf (stderr,"__mg_load_gif: error reading image\n");        return 0;    }    /*     *        If this is an "uninteresting picture" ignore it.     */    if (ignore) {        while (LWZReadByte(src, FALSE, c) >= 0);        return 0;    }    /*image = ImageNewCmap(len, height, cmapSize);*/    bmp->w = len;    bmp->h = height;    bmp->frames = 1;    bmp->depth = 8;    bmpComputePitch (8, len, &bmp->pitch, TRUE);    bmp->bits = malloc (height * bmp->pitch);    if(!bmp->bits)        return 0;    for (i = 0; i < cmapSize; i++) {        /*ImageSetCmap(image, i, cmap[CM_RED][i],                     cmap[CM_GREEN][i], cmap[CM_BLUE][i]);*/        pal[i].r = cmap[CM_RED][i];        pal[i].g = cmap[CM_GREEN][i];        pal[i].b = cmap[CM_BLUE][i];    }    while ((v = LWZReadByte(src, FALSE, c)) >= 0) {        bmp->bits[ypos * bmp->pitch + xpos] = v;        ++xpos;        if (xpos == len) {            xpos = 0;            if (interlace) {                switch (pass) {                case 0:                case 1:                    ypos += 8;                    break;                case 2:                    ypos += 4;                    break;                case 3:                    ypos += 2;                    break;                }                if (ypos >= height) {                    ++pass;                    switch (pass) {                    case 1:                        ypos = 4;                        break;                    case 2:                        ypos = 2;                        break;                    case 3:                        ypos = 1;                        break;                    default:                        goto fini;                    }                }            } else {                ++ypos;            }        }        if (ypos >= height)            break;    }fini:    return 1;}BOOL __mg_check_gif (MG_RWops* fp){    char buf[16];    char version[4];    if (!ReadOK (fp, buf, 6))        return FALSE;               /* not gif image*/    if (strncmp(buf, "GIF", 3) != 0)        return FALSE;    strncpy (version, buf + 3, 3);    version [3] = '\0';    if (strcmp(version, "87a") != 0 && strcmp(version, "89a") != 0) {        return FALSE;               /* image loading error*/    }    return TRUE;}#endif /* _GIF_FILE_SUPPORT */