96 lines
2.1 KiB
Go
96 lines
2.1 KiB
Go
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package bytesconv
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import (
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"bytes"
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"math/rand"
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"strings"
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"testing"
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"time"
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)
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var testString = "Albert Einstein: Logic will get you from A to B. Imagination will take you everywhere."
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var testBytes = []byte(testString)
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func rawBytesToStr(b []byte) string {
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return string(b)
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}
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func rawStrToBytes(s string) []byte {
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return []byte(s)
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}
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// go test -v
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func TestBytesToString(t *testing.T) {
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data := make([]byte, 1024)
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for i := 0; i < 100; i++ {
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rand.Read(data)
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if rawBytesToStr(data) != BytesToString(data) {
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t.Fatal("don't match")
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}
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}
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}
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const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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const (
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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var src = rand.NewSource(time.Now().UnixNano())
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func RandStringBytesMaskImprSrcSB(n int) string {
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sb := strings.Builder{}
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sb.Grow(n)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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sb.WriteByte(letterBytes[idx])
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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return sb.String()
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}
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func TestStringToBytes(t *testing.T) {
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for i := 0; i < 100; i++ {
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s := RandStringBytesMaskImprSrcSB(64)
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if !bytes.Equal(rawStrToBytes(s), StringToBytes(s)) {
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t.Fatal("don't match")
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}
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}
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}
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// go test -v -run=none -bench=^BenchmarkBytesConv -benchmem=true
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func BenchmarkBytesConvBytesToStrRaw(b *testing.B) {
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for i := 0; i < b.N; i++ {
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rawBytesToStr(testBytes)
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}
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}
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func BenchmarkBytesConvBytesToStr(b *testing.B) {
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for i := 0; i < b.N; i++ {
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BytesToString(testBytes)
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}
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}
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func BenchmarkBytesConvStrToBytesRaw(b *testing.B) {
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for i := 0; i < b.N; i++ {
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rawStrToBytes(testString)
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}
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}
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func BenchmarkBytesConvStrToBytes(b *testing.B) {
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for i := 0; i < b.N; i++ {
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StringToBytes(testString)
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}
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}
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