package rune

func isAscii(char rune) bool {
	ord := int(char)

	return ord < 0x80
}

func IsCtrl(char rune) bool {
	if !isAscii(char) {
		return false
	}

	ord := int(char)

	return ord == 0x7f || ord < 0x20
}

// Return the input code of a Ctrl-key chord.
func Ctrl(char rune) rune {
	ord := int(char)
	raw := ord & 0x1f

	if !IsCtrl(rune(raw)) {
		return 0
	}

	return rune(raw)
}