Benchmark concatinating rune slices

argh_test.go

package argh

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

// $ go test -run=XXX -bench=.
// BenchmarkConcatAppendConcatOnce-4        5000000               262 ns/op
// BenchmarkConcatCopyConcatOnce-4          5000000               227 ns/op
// BenchmarkConcatAppendReuse-4               20000             82434 ns/op
// BenchmarkConcatCopyReuse-4                  2000           1059490 ns/op

const repeat_concat = 100

var text1 = []rune("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus ut risus et enim consectetur convallis a non ipsum. Sed nec nibh cursus, interdum libero vel.")
var text1_1 = append(append([]rune{}, text1...), text1...)

func concat_append(r1, r2 []rune) []rune {
	return append(r1, r2...)
}

func concat_copy(r1, r2 []rune) []rune {
	result := make([]rune, len(r1)+len(r2))

	copy(result, r1)
	copy(result[len(r1):], r2)

	return result
}

func TestConcatAppend(t *testing.T) {
	assert.Equal(t, text1_1, concat_append(text1, text1))
}

func TestConcatCopy(t *testing.T) {
	assert.Equal(t, text1_1, concat_copy(text1, text1))
}

var result []rune

func BenchmarkConcatAppendConcatOnce(b *testing.B) {
	for n := 0; n < b.N; n++ {
		var rs = []rune{}

		result = concat_append(rs, text1)
	}
}

func BenchmarkConcatCopyConcatOnce(b *testing.B) {
	for n := 0; n < b.N; n++ {
		var rs = []rune{}

		result = concat_copy(rs, text1)
	}
}

func BenchmarkConcatAppendReuse(b *testing.B) {
	for n := 0; n < b.N; n++ {
		var rs = []rune{}

		for i := 0; i < repeat_concat; i++ {
			rs = concat_append(rs, text1)
		}

		result = rs
	}
}

func BenchmarkConcatCopyReuse(b *testing.B) {
	for n := 0; n < b.N; n++ {
		var rs = []rune{}

		for i := 0; i < repeat_concat; i++ {
			rs = concat_copy(rs, text1)
		}

		result = rs
	}
}