textmaster-medium-regex-perfomance-benchmark

benchmark.rb

require "benchmark/ips"

PART = <<TEXT
A text with 123,21231,231,23d a number: 12,212,234,12
Other 12 43 123,21231,22,22,2,33d Some other 9012,123123 12
TEXT
TEXT = PART * 100

POSSESSIVE = /(\d++,?)++/
LAZY = /(\d+?,?)+?/
NORMAL = /(\d+,?)+/
UNROLLING = /-?\d+(,\d+)*/

def count(string, regex)
  string.scan(regex).count
end

def compile_regex(regex)
  /(?<=\s)(#{regex})(?=\s)/
end

POSSESSIVE_WHOLE = compile_regex(POSSESSIVE)
LAZY_WHOLE = compile_regex(LAZY)
NORMAL_WHOLE = compile_regex(NORMAL)
UNROLLING_WHOLE = compile_regex(UNROLLING)

def measure(string, x)
  x.report('possessive') { count(string, POSSESSIVE_WHOLE) }
  x.report('lazy') { count(string, LAZY_WHOLE) }
  x.report('greedy') { count(string, NORMAL_WHOLE) }
  x.report('unrolling') { count(string, UNROLLING_WHOLE) }
  x.compare!
end

def benchmark(string)
  Benchmark.ips do |x|
    measure(string, x)
  end
end

benchmark(TEXT)