From 71e41a5b9495ba6ebe3cdf1e10afa27bcc0db208 Mon Sep 17 00:00:00 2001
From: Ryuta Kamizono <kamipo@gmail.com>
Date: Sun, 28 Jul 2019 17:16:03 +0900
Subject: Performance improvement for `String#to`
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```ruby
class String
  def to1(position)
    position = [position + length, -1].max if position < 0
    self[0, position + 1]
  end

  def to2(position)
    position += size if position < 0
    self[0, position + 1] || +""
  end
end

Benchmark.ips do |x|
  x.report("'foo'.to(1)")  { 'foo'.to(1) }
  x.report("'foo'.to1(1)") { 'foo'.to1(1) }
  x.report("'foo'.to2(1)") { 'foo'.to2(1) }

  x.report("'foo'.to(-1)")  { 'foo'.to(-1) }
  x.report("'foo'.to1(-1)") { 'foo'.to1(-1) }
  x.report("'foo'.to2(-1)") { 'foo'.to2(-1) }

  x.report("'foo'.to(-10)")  { 'foo'.to(-10) }
  x.report("'foo'.to1(-10)") { 'foo'.to1(-10) }
  x.report("'foo'.to2(-10)") { 'foo'.to2(-10) }
end
```

Result:

```
Warming up --------------------------------------
         'foo'.to(1)   199.859k i/100ms
        'foo'.to1(1)   220.293k i/100ms
        'foo'.to2(1)   221.522k i/100ms
        'foo'.to(-1)   205.032k i/100ms
       'foo'.to1(-1)   195.837k i/100ms
       'foo'.to2(-1)   214.975k i/100ms
       'foo'.to(-10)   214.331k i/100ms
      'foo'.to1(-10)   182.666k i/100ms
      'foo'.to2(-10)   224.696k i/100ms
Calculating -------------------------------------
         'foo'.to(1)      4.685M (± 4.2%) i/s -     23.583M in   5.042568s
        'foo'.to1(1)      5.233M (± 5.8%) i/s -     26.215M in   5.026778s
        'foo'.to2(1)      5.180M (± 5.7%) i/s -     25.918M in   5.020735s
        'foo'.to(-1)      4.253M (± 7.0%) i/s -     21.323M in   5.043133s
       'foo'.to1(-1)      4.438M (±11.2%) i/s -     21.934M in   5.025751s
       'foo'.to2(-1)      4.716M (± 9.8%) i/s -     23.432M in   5.028088s
       'foo'.to(-10)      4.678M (± 9.5%) i/s -     23.148M in   5.007379s
      'foo'.to1(-10)      4.428M (± 5.1%) i/s -     22.103M in   5.005155s
      'foo'.to2(-10)      5.243M (± 4.6%) i/s -     26.289M in   5.024695s
```
---
 activesupport/lib/active_support/core_ext/string/access.rb | 2 +-
 activesupport/lib/active_support/dependencies.rb           | 1 -
 activesupport/lib/active_support/secure_compare_rotator.rb | 1 -
 3 files changed, 1 insertion(+), 3 deletions(-)

(limited to 'activesupport')

diff --git a/activesupport/lib/active_support/core_ext/string/access.rb b/activesupport/lib/active_support/core_ext/string/access.rb
index eff31e5493..1a0b10b4f6 100644
--- a/activesupport/lib/active_support/core_ext/string/access.rb
+++ b/activesupport/lib/active_support/core_ext/string/access.rb
@@ -62,7 +62,7 @@ class String
   #   str.from(1).to(-2) # => "ell"
   def to(position)
     position += size if position < 0
-    self[0, position + 1].to_s
+    self[0, position + 1] || +""
   end
 
   # Returns the first character. If a limit is supplied, returns a substring
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index 923d6ad228..6d71a67a46 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -793,7 +793,6 @@ module ActiveSupport #:nodoc:
     end
 
     private
-
       # Returns the original name of a class or module even if `name` has been
       # overridden.
       def real_mod_name(mod)
diff --git a/activesupport/lib/active_support/secure_compare_rotator.rb b/activesupport/lib/active_support/secure_compare_rotator.rb
index 97110d41f7..269703c34a 100644
--- a/activesupport/lib/active_support/secure_compare_rotator.rb
+++ b/activesupport/lib/active_support/secure_compare_rotator.rb
@@ -44,7 +44,6 @@ module ActiveSupport
     end
 
     private
-
       def build_rotation(previous_value, _options)
         self.class.new(previous_value)
       end
-- 
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