int DecompBlock(unsigned char *cdata, unsigned char *buffer, int maxlen)
{
	unsigned char *bpos = buffer, *bpos2, tmp;

	while(*cdata != 0xFF) {
		int cmdtype = *cdata >> 5;
		int len = (*cdata & 0x1F) + 1;
		if(cmdtype == 7) {
			cmdtype = (*cdata & 0x1C) >> 2;
			len = ((*cdata & 3) << 8) + *(cdata + 1) + 1;
			cdata++;
		}
		if(bpos + len > &buffer[maxlen]) return -1;
		cdata++;
		if(cmdtype >= 4) {
			bpos2 = &buffer[(*cdata << 8) + *(cdata + 1)];
			if(bpos2 >= &buffer[maxlen]) return -1;
			cdata += 2;
		}
		switch(cmdtype) {
			case 0:
				memcpy(bpos, cdata, len);
				cdata += len;
				bpos += len;
				break;
			case 1:
				memset(bpos, *cdata++, len);
				bpos += len;
				break;
			case 2:
				if(bpos + 2 * len > &buffer[maxlen]) return -1;
				while(len--) {
					*(short *)bpos = *(short *)cdata;
					bpos += 2;
				}
				cdata += 2;
				break;
			case 3:
				tmp = *cdata++;
				while(len--) *bpos++ = tmp++;
				break;
			case 4:
				if(bpos2 + len > &buffer[maxlen]) return -1;
				memcpy(bpos, bpos2, len);
				bpos += len;
				break;
			case 5:
				if(bpos2 + len > &buffer[maxlen]) return -1;
				while(len--) {
					tmp = *bpos2++;
					/* reverse the bits */
					tmp = ((tmp >> 1) & 0x55) | ((tmp << 1) & 0xAA);
					tmp = ((tmp >> 2) & 0x33) | ((tmp << 2) & 0xCC);
					tmp = ((tmp >> 4) & 0x0F) | ((tmp << 4) & 0xF0);
					*bpos++ = tmp;
				}
				break;
			case 6:
				if(bpos2 - len + 1 < buffer) return -1;
				while(len--) *bpos++ = *bpos2--;
				break;
			case 7:
				return -1;
		}
	}
	return bpos - buffer;
}