test.rb

# encoding: utf-8

require 'rubygems'
require 'benchmark/ips'
require 'set'

TRUE_VALUES = [true, 1, '1', 't', 'T', 'true', 'TRUE'].to_set
BOOLEAN_MAP = Hash[ %w[ 1 on  t true  y yes ].product([ true ]) ]

def original value
  if value.is_a?(String) && value.empty?
    nil
  else
    TRUE_VALUES.include?(value)
  end
end

def regexp value
  case value
  when String
    value =~ /^(?:1|t(?:rue)?)$/i
  when true, 1
    true
  else
    false
  end
end

def boolean_map(value)
  BOOLEAN_MAP.fetch(value.downcase, value)
end

n = 50000
Benchmark.ips do |x|
  x.report('original hit') {
    original 'true'
  }

  x.report('original miss') {
    original 'false'
  }

  x.report('regex hit') {
    regexp 'true'
  }

  x.report('regex miss') {
    regexp 'false'
  }

  x.report('boolean_map hit') {
    original 'TrUE'
  }

  x.report('boolean_map miss') {
    original 'FaLSE'
  }
end