Use memchr for performance #3067

ksss · 2015-12-31T09:01:10Z

Use memchr for performance.

This code was copy from https://github.com/ruby/ruby/blob/2f2a5c3ae9f9e7a4d09b1500de8d864f48d69cad/re.c#L264-L269

benchmark

$ uname -v
Darwin Kernel Version 15.2.0: Fri Nov 13 19:56:56 PST 2015; root:xnu-3248.20.55~2/RELEASE_X86_64

s = "b"
str = ("a" * 100 + s)

t = Time.now
str.index(s)
puts Time.now - t

before => 0.000788
after => 0.000508

s = "b"
str = ("a" * 100 * 1024 * 1024 + s)

t = Time.now
str.index(s)
puts Time.now - t

before => 0.225474
after => 0.008658

```ruby s = "b" str = ("a" * 100 + s) t = Time.now str.index(s) puts Time.now - t ``` before => 0.000788 after => 0.000508 --- ```ruby s = "b" str = ("a" * 100 * 1024 * 1024 + s) t = Time.now str.index(s) puts Time.now - t ``` before => 0.225474 after => 0.008658

Use memchr for performance

mattn · 2016-01-05T07:49:14Z

@matz this should work well because this is binary comparing. do you expect mruby-string-ext should work as multi-byte? for example, "あ".index("\x81") should be 0 if string is utf-8.

…character boundary; ref #3067 that means String#index matches first byte of a multi-byte character. this behavior is different from CRuby, but a compromise for mruby which does not have encoding stuffs.

matz added a commit that referenced this issue Dec 31, 2015

Merge pull request #3067 from ksss/use-memchr

31b8469

Use memchr for performance

matz merged commit 31b8469 into mruby:master Dec 31, 2015
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ksss deleted the use-memchr branch Dec 31, 2015

tsahara mentioned this pull request Jan 5, 2016

make January 2016 Stable Release iij/mruby#156

Closed

Use memchr for performance #3067

Use memchr for performance #3067

ksss commented Dec 31, 2015

mattn commented Jan 5, 2016

Use memchr for performance #3067

Use memchr for performance #3067

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ksss commented Dec 31, 2015

benchmark

mattn commented Jan 5, 2016