1 files changed, 40 insertions, 0 deletions
diff --git a/common/format.go b/common/format.go
new file mode 100644
index 000000000..119637d2e
--- /dev/null
+++ b/common/format.go
@@ -0,0 +1,40 @@
+// 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
+}