unescape_test.go

package b

import (
	"bytes"
	"testing"
)

var needsEscape = []byte(`foo\ bar\"sne`)

func BenchmarkOrig(b *testing.B) {
	for i := 0; i < b.N; i++ {
		_ = Unescape(needsEscape)
	}
}

func BenchmarkNew(b *testing.B) {
	for i := 0; i < b.N; i++ {
		_ = UnescapeNew(needsEscape)
	}
}

func Unescape(in []byte) []byte {
	if len(in) == 0 {
		return nil
	}

	if bytes.IndexByte(in, '\\') == -1 {
		return in
	}

	i := 0
	inLen := len(in)
	var out []byte

	for {
		if i >= inLen {
			break
		}
		if in[i] == '\\' && i+1 < inLen {
			switch in[i+1] {
			case ',':
				out = append(out, ',')
				i += 2
				continue
			case '"':
				out = append(out, '"')
				i += 2
				continue
			case ' ':
				out = append(out, ' ')
				i += 2
				continue
			case '=':
				out = append(out, '=')
				i += 2
				continue
			}
		}
		out = append(out, in[i])
		i += 1
	}
	return out
}

func UnescapeNew(in []byte) []byte {
	if len(in) == 0 {
		return nil
	}

	if bytes.IndexByte(in, '\\') == -1 {
		return in
	}

	i := 0
	inLen := len(in)
	out := make([]byte, 0, inLen)

	for {
		if i >= inLen {
			break
		}
		if in[i] == '\\' && i+1 < inLen {
			switch in[i+1] {
			case ',':
				out = append(out, ',')
				i += 2
				continue
			case '"':
				out = append(out, '"')
				i += 2
				continue
			case ' ':
				out = append(out, ' ')
				i += 2
				continue
			case '=':
				out = append(out, '=')
				i += 2
				continue
			}
		}
		out = append(out, in[i])
		i += 1
	}
	return out
}