// Helper functions
package editor

import "strings"

// Truncate a string to a length
func truncateString(s string, length int) string {
	if length < 1 {
		return ""
	}

	var buf strings.Builder
	count := 0

	for _, char := range s {
		if count == length {
			break
		}

		buf.WriteRune(char)
		count++
	}

	return buf.String()
}

// Is this an ASCII character?
func isAscii(char rune) bool {
	return char < 0x80
}

// Is this an ASCII ctrl character?
func isCtrl(char rune) bool {
	if !isAscii(char) {
		return false
	}

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

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

	if !isCtrl(ch) {
		return 0
	}

	return ch
}