package nbyte

// IsLower checks if a character is lower case ('a' to 'z')
func IsLower(c byte) bool {
	return 'a' <= c && c <= 'z'
}

// ToLower converts a character  'A' to 'Z' to its lower case
func ToLower(c byte) byte {
	if c >= 'A' && c <= 'Z' {
		return c + 32
	}
	return c
}

// ToLowerAll converts a character  'A' to 'Z' to its lower case
func ToLowerAll(bs []byte) []byte {
	for i := range bs {
		bs[i] = ToLower(bs[i])
	}
	return bs
}

// IsUpper checks if a character is upper case ('A' to 'Z')
func IsUpper(c byte) bool {
	return 'A' <= c && c <= 'Z'
}

// ToUpper converts a character  'a' to 'z' to its upper case
func ToUpper(r byte) byte {
	if r >= 'a' && r <= 'z' {
		return r - 32
	}
	return r
}

// ToUpperAll converts a character  'a' to 'z' to its upper case
func ToUpperAll(rs []byte) []byte {
	for i := range rs {
		rs[i] = ToUpper(rs[i])
	}
	return rs
}

// IsDigit checks if a character is digit ('0' to '9')
func IsDigit(r byte) bool {
	return r >= '0' && r <= '9'
}

// IsAlphabet byte
func IsAlphabet(char byte) bool {
	// A 65 -> Z 90
	if char >= 'A' && char <= 'Z' {
		return true
	}

	// a 97 -> z 122
	if char >= 'a' && char <= 'z' {
		return true
	}
	return false
}