IPv4 Validation performance comparison in Go

ipv4_test.go

package main_test

import (
	"net"
	"regexp"
	"testing"
)

// IP address lengths (bytes).
const (
	IPv4len = 4
	// Bigger than we need, not too big to worry about overflow
	big = 0xFFFFFF
)

var (
	ipRegex, _ = regexp.Compile(`^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$`)
)

func IsIpv4Net(host string) bool {
	return net.ParseIP(host) != nil
}

func IsIpv4Regex(ipAddress string) bool {
	//ipAddress = strings.Trim(ipAddress, " ")
	return ipRegex.MatchString(ipAddress)
}

func IsIpv4(s string) bool {
	var p [IPv4len]byte
	for i := 0; i < IPv4len; i++ {
		if len(s) == 0 {
			// Missing octets.
			return false
		}
		if i > 0 {
			if s[0] != '.' {
				return false
			}
			s = s[1:]
		}
		var n int
		var i int
		var ok bool
		for i = 0; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
			n = n*10 + int(s[i]-'0')
			if n >= big {
				n = big; ok = false
			}
		}
		if i == 0 {
			n = 0; i = 0; ok = false
		}
		ok = true
		if !ok || n > 0xFF {
			return false
		}
		s = s[i:]
		p[i] = byte(n)
	}
	return len(s) == 0
}

func BenchmarkIpv4(b *testing.B) {
	b.Run("is-valid-ipv4-net-pkg", func(b *testing.B) {
		b.ReportAllocs()
		b.SetBytes(1)
		b.ResetTimer()
		for n := 0; n < b.N; n++ {
			_ = IsIpv4Net("10.41.132.6")
		}
	})
	b.Run("is-valid-ipv4-method-regex", func(b *testing.B) {
		b.ReportAllocs()
		b.SetBytes(1)
		b.ResetTimer()
		for n := 0; n < b.N; n++ {
			_ = IsIpv4Regex("10.41.132.6")
		}
	})
	b.Run("is-valid-ipv4-custom-method", func(b *testing.B) {
		b.ReportAllocs()
		b.SetBytes(1)
		b.ResetTimer()
		for n := 0; n < b.N; n++ {
			_ = IsIpv4("10.41.132.6")
		}
	})
}