benchmark.rb

# frozen_string_literal: true

require "bundler/setup"

require "active_model"
require "benchmark/ips"

class NewTime < ActiveModel::Type::Time
  private
    def cast_value(value)
      return apply_seconds_precision(value) unless value.is_a?(::String)
      return if value.empty?

      dummy_time_value = value.sub(/\A\d{4}-\d\d-\d\d(?:T|\s)|/, "2000-01-01 ")

      fast_string_to_time(dummy_time_value) || begin
        time_hash = ::Date._parse(dummy_time_value)
        return if time_hash[:hour].nil?
        new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction, :offset))
      end
    end
end

type = ActiveModel::Type::Time.new
new_type = NewTime.new

SCENARIOS = {
  "Incomplete" => "06:07:08+09:00",
  "ISO"  => "2015-06-13T19:45:54+03:00",
  "Hash" => { 4 => 16, 5 => 45, 6 => 54 }
}

SCENARIOS.each_pair do |name, value|
  puts
  puts " #{name} ".center(80, "=")
  puts

  Benchmark.ips do |x|
    x.report("old") { type.cast(value) }
    x.report("new") { new_type.cast(value) }
    x.compare!
  end
end

result

================================== Incomplete ==================================

Warming up --------------------------------------
                 old    21.970k i/100ms
                 new    20.542k i/100ms
Calculating -------------------------------------
                 old    211.402k (± 2.7%) i/s -      1.077M in   5.096092s
                 new    207.805k (± 2.4%) i/s -      1.048M in   5.044402s

Comparison:
                 old:   211401.7 i/s
                 new:   207805.1 i/s - same-ish: difference falls within error


===================================== ISO ======================================

Warming up --------------------------------------
                 old     5.523k i/100ms
                 new    20.959k i/100ms
Calculating -------------------------------------
                 old     56.738k (± 3.2%) i/s -    287.196k in   5.067285s
                 new    205.978k (± 3.8%) i/s -      1.048M in   5.094470s

Comparison:
                 new:   205978.5 i/s
                 old:    56737.6 i/s - 3.63x  (± 0.00) slower


===================================== Hash =====================================

Warming up --------------------------------------
                 old    20.880k i/100ms
                 new    19.386k i/100ms
Calculating -------------------------------------
                 old    202.984k (± 2.9%) i/s -      1.023M in   5.045013s
                 new    203.073k (± 2.2%) i/s -      1.027M in   5.061994s

Comparison:
                 new:   203073.4 i/s
                 old:   202983.6 i/s - same-ish: difference falls within error