diff options
author | Tobias Klauser <tklauser@distanz.ch> | 2019-03-09 14:11:40 +0100 |
---|---|---|
committer | Tobias Klauser <tobias.klauser@gmail.com> | 2019-03-09 14:17:13 +0000 |
commit | 0e9d7d430b1aa74a58054a6a69aa3fb37353168d (patch) | |
tree | 4959d9f1112dc72296336b6259c00f0b905842fe /src/bytes | |
parent | ca8354843ef9f30207efd0a40bb6c53e7ba86892 (diff) | |
download | go-0e9d7d430b1aa74a58054a6a69aa3fb37353168d.tar.gz go-0e9d7d430b1aa74a58054a6a69aa3fb37353168d.zip |
bytes: return early in Repeat if count is 0
This matches the implementation of strings.Repeat and slightly increases
performance:
name old time/op new time/op delta
Repeat-8 145ns ±12% 125ns ±29% -13.35% (p=0.009 n=10+10)
Change-Id: Ic0a0e2ea9e36591286a49def320ddb67fe0b2c50
Reviewed-on: https://go-review.googlesource.com/c/go/+/166399
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Diffstat (limited to 'src/bytes')
-rw-r--r-- | src/bytes/bytes.go | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/bytes/bytes.go b/src/bytes/bytes.go index f65bf214cc..6fcebe6593 100644 --- a/src/bytes/bytes.go +++ b/src/bytes/bytes.go @@ -499,13 +499,16 @@ func Map(mapping func(r rune) rune, s []byte) []byte { // It panics if count is negative or if // the result of (len(b) * count) overflows. func Repeat(b []byte, count int) []byte { + if count == 0 { + return []byte{} + } // Since we cannot return an error on overflow, // we should panic if the repeat will generate // an overflow. // See Issue golang.org/issue/16237. if count < 0 { panic("bytes: negative Repeat count") - } else if count > 0 && len(b)*count/count != len(b) { + } else if len(b)*count/count != len(b) { panic("bytes: Repeat count causes overflow") } |