format.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package common

import (
	"fmt"
	"regexp"
	"strings"
	"time"
)

// PrettyDuration is a pretty printed version of a time.Duration value that cuts
// the unnecessary precision off from the formatted textual representation.
type PrettyDuration time.Duration

var prettyDurationRe = regexp.MustCompile(`\.[0-9]+`)

// String implements the Stringer interface, allowing pretty printing of duration
// values rounded to three decimals.
func (d PrettyDuration) String() string {
	label := fmt.Sprintf("%v", time.Duration(d))
	if match := prettyDurationRe.FindString(label); len(match) > 4 {
		label = strings.Replace(label, match, match[:4], 1)
	}
	return label
}