Golang Fast: Converting 9-Digit Integers to Bytes Benchmark

int_to_byte_conversion_benchmark.go

package benchmark

import (
	"strconv"
	"testing"
)

var resultSink []byte

func BenchmarkConvertIntToString(b *testing.B) {
	integerVal := 151795072

	for i := 0; i < b.N; i++ {
		stringByteVal := []byte(strconv.Itoa(integerVal))

		resultSink = stringByteVal
	}
}

func BenchmarkConvertIntToStringAppend(b *testing.B) {
	integerVal := int64(151795072)

	for i := 0; i < b.N; i++ {
		var stringByteVal []byte

		stringByteVal = strconv.AppendInt(stringByteVal, integerVal, 10)

		resultSink = stringByteVal
	}
}

func writeFixedIntToBuffer(n int, buf []byte) {
	// Direct conversion for a fixed 9-digit positive number
	buf[8] = byte('0' + n%10)
	n /= 10
	buf[7] = byte('0' + n%10)
	n /= 10
	buf[6] = byte('0' + n%10)
	n /= 10
	buf[5] = byte('0' + n%10)
	n /= 10
	buf[4] = byte('0' + n%10)
	n /= 10
	buf[3] = byte('0' + n%10)
	n /= 10
	buf[2] = byte('0' + n%10)
	n /= 10
	buf[1] = byte('0' + n%10)
	n /= 10
	buf[0] = byte('0' + n%10)
}

func BenchmarkConvertIntToStringCustom(b *testing.B) {
	integerVal := 151795072

	for i := 0; i < b.N; i++ {
		stringByteVal := make([]byte, 9)

		writeFixedIntToBuffer(integerVal, stringByteVal)

		resultSink = stringByteVal
	}
}

func BenchmarkConvertIntToStringReuseVar(b *testing.B) {
	integerVal := 151795072

	stringByteVal := make([]byte, 9)

	for i := 0; i < b.N; i++ {
		copy(stringByteVal, []byte(strconv.Itoa(integerVal)))

		resultSink = stringByteVal
	}
}

func BenchmarkConvertIntToStringCustomReuseBuffer(b *testing.B) {
	integerVal := 151795072

	stringByteVal := make([]byte, 9)

	for i := 0; i < b.N; i++ {
		writeFixedIntToBuffer(integerVal, stringByteVal)

		resultSink = stringByteVal
	}
}

/*
BenchmarkConvertIntToString-32                          39900381                28.99 ns/op           32 B/op          2 allocs/op
BenchmarkConvertIntToStringAppend-32                    58533729                20.73 ns/op           16 B/op          1 allocs/op
BenchmarkConvertIntToStringCustom-32                    71037862                16.27 ns/op           16 B/op          1 allocs/op
BenchmarkConvertIntToStringReuseVar-32                  65780457                18.04 ns/op           16 B/op          1 allocs/op
BenchmarkConvertIntToStringCustomReuseBuffer-32         146857864                8.182 ns/op           0 B/op          0 allocs/op
*/