4bc9badd75
Switch statements do a binary search on long runs of constants. Doing a less-than comparison on a string is much more expensive than on (say) an int. Use two part comparison for strings: First compare length, then the strings themselves. Benchmarks from issue 10000: benchmark old ns/op new ns/op delta BenchmarkIf0 3.36 3.35 -0.30% BenchmarkIf1 4.45 4.47 +0.45% BenchmarkIf2 5.22 5.26 +0.77% BenchmarkIf3 5.56 5.58 +0.36% BenchmarkIf4 10.5 10.6 +0.95% BenchmarkIfNewStr0 5.26 5.30 +0.76% BenchmarkIfNewStr1 7.19 7.15 -0.56% BenchmarkIfNewStr2 7.23 7.16 -0.97% BenchmarkIfNewStr3 7.47 7.43 -0.54% BenchmarkIfNewStr4 12.4 12.2 -1.61% BenchmarkSwitch0 9.56 4.24 -55.65% BenchmarkSwitch1 8.64 5.58 -35.42% BenchmarkSwitch2 9.38 10.1 +7.68% BenchmarkSwitch3 8.66 5.00 -42.26% BenchmarkSwitch4 7.99 8.18 +2.38% BenchmarkSwitchNewStr0 11.3 6.12 -45.84% BenchmarkSwitchNewStr1 11.1 8.33 -24.95% BenchmarkSwitchNewStr2 11.0 11.1 +0.91% BenchmarkSwitchNewStr3 10.3 6.93 -32.72% BenchmarkSwitchNewStr4 11.0 11.2 +1.82% Fixes #10000 Change-Id: Ia2fffc32e9843425374c274064f709ec7ee46d80 Reviewed-on: https://go-review.googlesource.com/7698 Reviewed-by: Keith Randall <khr@golang.org> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.
Please report issues here: https://golang.org/issue/new
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Please note that we do not use pull requests.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.