Golang: Suffix match benchmark, regexp vs rune match

README.md

BenchmarkSuffixMatchByRuneLength10	10000000	       226 ns/op
BenchmarkSuffixMatchByRuneLength30	 5000000	       630 ns/op
BenchmarkSuffixMatchByRegexpLength10	 1000000	      2033 ns/op
BenchmarkSuffixMatchByRegexpLength30	  500000	      4863 ns/op

bench_test.go

package main

import (
	"regexp"
	"testing"
)

func isDigit(r rune) bool {
	return '0' <= r && r <= '9'
}

type RuneMatcherFunc func(r rune) bool

type SuffixMatcher struct {
	suffix string
	f      RuneMatcherFunc
}

func (m *SuffixMatcher) Match(s string) int {
	d := len(s) - len(m.suffix)
	// at least 1 character is required to match suffix and matcher
	if d < 1 {
		return -1
	}

	for i, r := range s {
		if i > d {
			return -1
		}

		// peek string to match to suffix pattern
		if i != 0 && m.suffix == s[i:i+len(m.suffix)] {
			return i + len(m.suffix)
		}

		if !m.f(r) {
			return -1
		}
	}

	return -1
}

func BenchmarkSuffixMatchByRuneLength10(b *testing.B) {
	b.StopTimer()
	m := &SuffixMatcher{"/about", RuneMatcherFunc(isDigit)}
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		if index := m.Match("0123456789/about"); index != 16 {
			panic("broken matcher")
		}
	}
}

func BenchmarkSuffixMatchByRuneLength30(b *testing.B) {
	b.StopTimer()
	m := &SuffixMatcher{"/about", RuneMatcherFunc(isDigit)}
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		if index := m.Match("012345678901234567890123456789/about"); index != 36 {
			panic("broken matcher")
		}
	}
}

func BenchmarkSuffixMatchByRegexpLength10(b *testing.B) {
	b.StopTimer()
	r := regexp.MustCompile(`^\d+\/about$`)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		if ok := r.MatchString("0123456789/about"); !ok {
			panic("broken regexp matcher")
		}
	}
}

func BenchmarkSuffixMatchByRegexpLength30(b *testing.B) {
	b.StopTimer()
	r := regexp.MustCompile(`^\d+\/about$`)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		if ok := r.MatchString("012345678901234567890123456789/about"); !ok {
			panic("broken regexp matcher")
		}
	}
}