Bug #13773: Improve String#prepend performance if only one argument is given

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN

[watson1978 (Shizuo Fujita)]

This is very similar with https://github.com/ruby/ruby/pull/1634
If only one argument is given, this will prepend the string without
generating temporary object.

String#prepend -> 47.5 % up

Before

      String#prepend      1.517M (± 1.8%) i/s -      7.614M in   5.019819s

After

      String#prepend      2.236M (± 3.4%) i/s -     11.234M in   5.029716s

Test code

require 'benchmark/ips'

Benchmark.ips do |x|
  x.report "String#prepend" do |loop|
    loop.times { "!".prepend("hello") }
  end
end

Patch

https://github.com/ruby/ruby/pull/1670

[watson1978 (Shizuo Fujita)]

• Status changed from Open to Closed

Applied in changeset trunk|r60480.

---

string.c: Improve String#prepend performance if only one argument is given

• string.c (rb_str_prepend_multi): Prepend the string without generating
  temporary String object if only one argument is given.
  This is very similar with https://github.com/ruby/ruby/pull/1634

  String#prepend -> 47.5 % up

  [Fix GH-1670] [ruby-core:82195] [Bug #13773]

• Before
  String#prepend 1.517M (± 1.8%) i/s - 7.614M in 5.019819s

• After
  String#prepend 2.236M (± 3.4%) i/s - 11.234M in 5.029716s

• Test code
  require 'benchmark/ips'

Benchmark.ips do |x|
x.report "String#prepend" do |loop|
loop.times { "!".prepend("hello") }
end
end