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| author | Ignacio Hagopian <jsign.uy@gmail.com> | 2021-08-17 23:52:00 +0000 |
|---|---|---|
| committer | Robert Griesemer <gri@golang.org> | 2021-08-22 23:49:55 +0000 |
| commit | 86ee89225aea2326fd50dbeb233cfc622413a4cf (patch) | |
| tree | 370a1847d84bd36d596af360ebdd37a3af6cba58 /src | |
| parent | 29d7e5472be79b77f39d81b697d44038179ba1a1 (diff) | |
| download | go-86ee89225aea2326fd50dbeb233cfc622413a4cf.tar.gz go-86ee89225aea2326fd50dbeb233cfc622413a4cf.zip | |
strings: smarter growth of temporal buffer and avoid copying on return
The implementation for single strings had two optimization opportunities:
1. Grow the temporary buffer by known size before appending.
2. Avoid a full copy of the result since the underlying buffer won't be mutated afterward.
Both things were leveraged by using a Builder instead of a byte slice.
Relevant benchmark results:
name old time/op new time/op delta
SingleMatch-8 32.0µs ± 3% 26.1µs ± 3% -18.41% (p=0.000 n=9+10)
name old speed new speed delta
SingleMatch-8 469MB/s ± 3% 574MB/s ± 3% +22.56% (p=0.000 n=9+10)
name old alloc/op new alloc/op delta
SingleMatch-8 81.3kB ± 0% 49.0kB ± 0% -39.67% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
SingleMatch-8 19.0 ± 0% 11.0 ± 0% -42.11% (p=0.000 n=10+10)
Change-Id: I23af56a15875206c0ff4ce29a51bec95fd48bb11
GitHub-Last-Rev: 403cfc3c2794b5da27792c51999417a2a052b365
GitHub-Pull-Request: golang/go#47766
Reviewed-on: https://go-review.googlesource.com/c/go/+/343089
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Robert Griesemer <gri@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/strings/replace.go | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/src/strings/replace.go b/src/strings/replace.go index e28d428879..ee728bb22b 100644 --- a/src/strings/replace.go +++ b/src/strings/replace.go @@ -387,7 +387,7 @@ func makeSingleStringReplacer(pattern string, value string) *singleStringReplace } func (r *singleStringReplacer) Replace(s string) string { - var buf []byte + var buf Builder i, matched := 0, false for { match := r.finder.next(s[i:]) @@ -395,15 +395,16 @@ func (r *singleStringReplacer) Replace(s string) string { break } matched = true - buf = append(buf, s[i:i+match]...) - buf = append(buf, r.value...) + buf.Grow(match + len(r.value)) + buf.WriteString(s[i : i+match]) + buf.WriteString(r.value) i += match + len(r.finder.pattern) } if !matched { return s } - buf = append(buf, s[i:]...) - return string(buf) + buf.WriteString(s[i:]) + return buf.String() } func (r *singleStringReplacer) WriteString(w io.Writer, s string) (n int, err error) { |