truncate.go

// SPDX-License-Identifier: MIT
//
// Copyright (c) 2019 GitHub Inc.
//               2022 Unikraft GmbH.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package text

import (
	"strings"

	"github.com/muesli/reflow/ansi"
	"github.com/muesli/reflow/truncate"
)

const (
	ellipsis            = "..."
	minWidthForEllipsis = len(ellipsis) + 2
)

// DisplayWidth calculates what the rendered width of a string may be
func DisplayWidth(s string) int {
	return ansi.PrintableRuneWidth(s)
}

// Truncate shortens a string to fit the maximum display width
func Truncate(maxWidth int, s string) string {
	w := DisplayWidth(s)
	if w <= maxWidth {
		return s
	}

	tail := ""
	if maxWidth >= minWidthForEllipsis {
		tail = ellipsis
	}

	r := truncate.StringWithTail(s, uint(maxWidth), tail)
	if DisplayWidth(r) < maxWidth {
		r += " "
	}

	return r
}

// TruncateColumn replaces the first new line character with an ellipsis
// and shortens a string to fit the maximum display width
func TruncateColumn(maxWidth int, s string) string {
	if i := strings.IndexAny(s, "\r\n"); i >= 0 {
		s = s[:i] + ellipsis
	}
	return Truncate(maxWidth, s)
}