static void xan_unpack(unsigned char *dest, unsigned char *src)
static void xan_unpack(unsigned char *dest, unsigned char *src, int dest_len)
static void xan_unpack(unsigned char *dest, unsigned char *src){    unsigned char opcode;    int size;    int offset;    int byte1, byte2, byte3;    for (;;) {        opcode = *src++;        if ( (opcode & 0x80) == 0 ) {            offset = *src++;            size = opcode & 3;            bytecopy(dest, src, size);  dest += size;  src += size;            size = ((opcode & 0x1c) >> 2) + 3;            bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);            dest += size;        } else if ( (opcode & 0x40) == 0 ) {            byte1 = *src++;            byte2 = *src++;            size = byte1 >> 6;            bytecopy (dest, src, size);  dest += size;  src += size;            size = (opcode & 0x3f) + 4;            bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);            dest += size;        } else if ( (opcode & 0x20) == 0 ) {            byte1 = *src++;            byte2 = *src++;            byte3 = *src++;            size = opcode & 3;            bytecopy (dest, src, size);  dest += size;  src += size;            size = byte3 + 5 + ((opcode & 0xc) << 6);            bytecopy (dest,                dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),                size);            dest += size;        } else {            size = ((opcode & 0x1f) << 2) + 4;            if (size > 0x70)                break;            bytecopy (dest, src, size);  dest += size;  src += size;        }    }    size = opcode & 3;    bytecopy(dest, src, size);  dest += size;  src += size;}