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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,19 @@ | ||
| package httprouter | ||
|
|
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| import ( | ||
| "reflect" | ||
| "unsafe" | ||
| ) | ||
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| // StringToBytes converts string to byte slice without a memory allocation. | ||
| func StringToBytes(s string) (b []byte) { | ||
| sh := *(*reflect.StringHeader)(unsafe.Pointer(&s)) | ||
| bh := (*reflect.SliceHeader)(unsafe.Pointer(&b)) | ||
| bh.Data, bh.Len, bh.Cap = sh.Data, sh.Len, sh.Len | ||
| return b | ||
| } | ||
|
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| // BytesToString converts byte slice to string without a memory allocation. | ||
| func BytesToString(s []byte) string { | ||
| return *(*string)(unsafe.Pointer(&s)) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,96 @@ | ||
| package httprouter | ||
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|
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| import ( | ||
| "bytes" | ||
| "math/rand" | ||
| "testing" | ||
| "time" | ||
| ) | ||
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| var testString = "Albert Einstein: Logic will get you from A to B. Imagination will take you everywhere." | ||
| var testBytes = []byte(testString) | ||
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| func rawBytesToStr(b []byte) string { | ||
| return string(b) | ||
| } | ||
|
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| func rawStrToBytes(s string) []byte { | ||
| return []byte(s) | ||
| } | ||
|
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| // go test -v | ||
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| func TestBytesToString(t *testing.T) { | ||
| data := make([]byte, 1024) | ||
| for i := 0; i < 100; i++ { | ||
| rand.Read(data) | ||
| if rawBytesToStr(data) != BytesToString(data) { | ||
| t.Fatal("don't match") | ||
| } | ||
| } | ||
| } | ||
|
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| const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" | ||
| const ( | ||
| letterIdxBits = 6 // 6 bits to represent a letter index | ||
| letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits | ||
| letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits | ||
| ) | ||
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| var src = rand.NewSource(time.Now().UnixNano()) | ||
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| func RandStringBytesMaskImprSrc(n int) string { | ||
| b := make([]byte, n) | ||
| // A src.Int63() generates 63 random bits, enough for letterIdxMax characters! | ||
| for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; { | ||
| if remain == 0 { | ||
| cache, remain = src.Int63(), letterIdxMax | ||
| } | ||
| if idx := int(cache & letterIdxMask); idx < len(letterBytes) { | ||
| b[i] = letterBytes[idx] | ||
| i-- | ||
| } | ||
| cache >>= letterIdxBits | ||
| remain-- | ||
| } | ||
| return string(b) | ||
| } | ||
|
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| func TestStringToBytes(t *testing.T) { | ||
| for i := 0; i < 100; i++ { | ||
| s := RandStringBytesMaskImprSrc(64) | ||
| if !bytes.Equal(rawStrToBytes(s), StringToBytes(s)) { | ||
| t.Fatal("don't match") | ||
| } | ||
| } | ||
| } | ||
|
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| // go test -v -run=none -bench=^BenchmarkBytesConv -benchmem=true | ||
|
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| func BenchmarkBytesConvBytesToStrRaw(b *testing.B) { | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| rawBytesToStr(testBytes) | ||
| } | ||
| } | ||
|
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| func BenchmarkBytesConvBytesToStr(b *testing.B) { | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| BytesToString(testBytes) | ||
| } | ||
| } | ||
|
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| func BenchmarkBytesConvStrToBytesRaw(b *testing.B) { | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| rawStrToBytes(testString) | ||
| } | ||
| } | ||
|
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| func BenchmarkBytesConvStrToBytes(b *testing.B) { | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| StringToBytes(testString) | ||
| } | ||
| } |
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