From 30a9957aacb21fef5195a43dba99669465a789e7 Mon Sep 17 00:00:00 2001 From: Brad Fitzpatrick Date: Thu, 7 Feb 2013 16:00:06 -0800 Subject: [PATCH] bytes: minor optimization to lastIndexFunc Before and after: BenchmarkTrimSpace 20000000 81.3 ns/op BenchmarkTrimSpace 50000000 58.0 ns/op (most whitespace trimming is ASCII whitespace) Same optimization appeared a handful of other places in this file, but not here. R=golang-dev, dave CC=golang-dev https://golang.org/cl/7305063 --- src/pkg/bytes/bytes.go | 5 ++++- src/pkg/bytes/bytes_test.go | 7 +++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/src/pkg/bytes/bytes.go b/src/pkg/bytes/bytes.go index 31cf89ea87..6d40af4436 100644 --- a/src/pkg/bytes/bytes.go +++ b/src/pkg/bytes/bytes.go @@ -571,7 +571,10 @@ func indexFunc(s []byte, f func(r rune) bool, truth bool) int { // inverted. func lastIndexFunc(s []byte, f func(r rune) bool, truth bool) int { for i := len(s); i > 0; { - r, size := utf8.DecodeLastRune(s[0:i]) + r, size := rune(s[i-1]), 1 + if r >= utf8.RuneSelf { + r, size = utf8.DecodeLastRune(s[0:i]) + } i -= size if f(r) == truth { return i diff --git a/src/pkg/bytes/bytes_test.go b/src/pkg/bytes/bytes_test.go index 1d073b143b..1d6274c33d 100644 --- a/src/pkg/bytes/bytes_test.go +++ b/src/pkg/bytes/bytes_test.go @@ -1073,3 +1073,10 @@ func BenchmarkFieldsFunc(b *testing.B) { FieldsFunc(fieldsInput, unicode.IsSpace) } } + +func BenchmarkTrimSpace(b *testing.B) { + s := []byte(" Some text. \n") + for i := 0; i < b.N; i++ { + TrimSpace(s) + } +} -- 2.48.1