[macruby-changes] [MacRuby/MacRuby] e664c0: improve a performance in String#+

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/MacRuby/MacRuby
  Commit: e664c0ecdd615885ea9ce12ff18d71cd50d9a321
      https://github.com/MacRuby/MacRuby/commit/e664c0ecdd615885ea9ce12ff18d71cd50d9a321
  Author: Watson <watson1978 at gmail.com>
  Date:   2012-12-29 (Sat, 29 Dec 2012)

  Changed paths:
    M string.c

  Log Message:
  -----------
  improve a performance in String#+

it reserves a heap area to store a concatenated string because it is slow to resize a heap.

* before
      user     system      total        real
  0.390000   0.230000   0.620000 (  0.608497)

* after
      user     system      total        real
  0.330000   0.050000   0.380000 (  0.380267)

Test Code:
----
require 'benchmark'

str = "abc" * 100
str1 = str * 100
str2 = str * 200

Benchmark.bm do |x|
  x.report do
    10000.times do
      str1 + str2
    end
  end
end