package rrdbinary

// RPNToken is one of the things that can be stored in a Unival; used
// by DST_CDEF.
type RPNToken struct {
	Op  uint8 // rpn operator type
	Val int32 // used by OP_NUMBER (0), OP_VARIABLE (1), and OP_PREV_OTHER (36)
}

// AsRPNTokens returns 1 or 2 RPNTokens (depending on the
// Architecture.ShortSize).
func (u Unival) AsRPNTokens() []RPNToken {
	var ret []RPNToken
	data := u.data
	for len(data) > 0 {
		rpnpData := data[:u.arch.ShortAlign+u.arch.ShortWidth]
		var rpnp RPNToken
		rpnp.Op = rpnpData[0]
		switch u.arch.ShortWidth {
		case 2:
			rpnp.Val = int32(int16(u.arch.ByteOrder.Uint16(rpnpData[u.arch.ShortAlign:])))
		case 4:
			rpnp.Val = int32(u.arch.ByteOrder.Uint32(rpnpData[u.arch.ShortAlign:]))
		}
		ret = append(ret, rpnp)
		data = data[len(rpnpData):]
	}
	return ret
}