regex_bench.rb

########### THIS BENCH DOES NOT USE METHODS ###########

require 'benchmark/ips'

LONG_STRING = "   this is a longer test
      this is a longer test
      this is a longer test
      this is a longer test
      this is a longer test"


Benchmark.ips do |x|
  x.report('old') do |times| 
    i = 0
    while i < times
      LONG_STRING.empty? || /\A[[:space:]]*\z/ === LONG_STRING
      i += 1
    end
  end
  x.report('new') do |times| 
    i = 0
    while i < times
      LONG_STRING.empty? || !(/[[:^space:]]/ === LONG_STRING)
      i += 1
    end
  end
  x.compare!
end
# Warming up --------------------------------------
#                  old    97.254k i/100ms
#                  new   127.135k i/100ms
# Calculating -------------------------------------
#                  old      1.836M (±10.9%) i/s -      9.142M in   5.040422s
#                  new      2.684M (±15.5%) i/s -     13.095M in   5.038331s

# Comparison:
#                  new:  2684299.7 i/s
#                  old:  1836420.8 i/s - 1.46x slower



########### THIS BENCH DOES USE METHODS & THE RESULTS ARE FLIPPED ###########


NEW_REGEX = /[[:^space:]]/
OLD_REGEX = /\A[[:space:]]*\z/

def new_blank(str)
  str.empty? || !(NEW_REGEX === str)
end

def old_blank(str)
  str.empty? || OLD_REGEX === str
end

Benchmark.ips do |x|
  x.report('old') do |times| 
    i = 0
    while i < times
      old_blank(LONG_STRING)
      i += 1
    end
  end
  x.report('new') do |times| 
    i = 0
    while i < times
      new_blank(LONG_STRING)
      i += 1
    end
  end
  x.compare!
end

# Warming up --------------------------------------
#                  old   108.721k i/100ms
#                  new    64.769k i/100ms
# Calculating -------------------------------------
#                  old      1.745M (±10.5%) i/s -      8.698M in   5.044805s
#                  new    869.410k (± 8.8%) i/s -      4.340M in   5.031931s
# Comparison:
#                  old:  1744606.1 i/s
#                  new:   869410.3 i/s - 2.01x slower
#