60 lines
2.4 KiB
Go
60 lines
2.4 KiB
Go
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package pkg
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import (
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"reflect"
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"unsafe"
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)
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/*
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使用 unsafe 的方式转换 bytes string
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bench-review
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cpu: Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz
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BenchmarkB2sFast
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BenchmarkB2sFast 1000000000 0.2215 ns/op 0 B/op 0 allocs/op
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BenchmarkB2sFast-4 1000000000 0.2188 ns/op 0 B/op 0 allocs/op
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BenchmarkB2sFast-8 1000000000 0.2187 ns/op 0 B/op 0 allocs/op
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BenchmarkB2sFast-16 1000000000 0.2190 ns/op 0 B/op 0 allocs/op
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BenchmarkB2sStd
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BenchmarkB2sStd 46913166 25.01 ns/op 48 B/op 1 allocs/op
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BenchmarkB2sStd-4 53604633 21.23 ns/op 48 B/op 1 allocs/op
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BenchmarkB2sStd-8 53374398 21.27 ns/op 48 B/op 1 allocs/op
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BenchmarkB2sStd-16 55482764 21.51 ns/op 48 B/op 1 allocs/op
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BenchmarkS2BFast
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BenchmarkS2BFast 1000000000 0.2187 ns/op 0 B/op 0 allocs/op
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BenchmarkS2BFast-4 1000000000 0.2187 ns/op 0 B/op 0 allocs/op
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BenchmarkS2BFast-8 1000000000 0.2184 ns/op 0 B/op 0 allocs/op
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BenchmarkS2BFast-16 1000000000 0.2188 ns/op 0 B/op 0 allocs/op
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BenchmarkS2BStd
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BenchmarkS2BStd 56877040 21.31 ns/op 48 B/op 1 allocs/op
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BenchmarkS2BStd-4 65751385 17.43 ns/op 48 B/op 1 allocs/op
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BenchmarkS2BStd-8 67193628 17.55 ns/op 48 B/op 1 allocs/op
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BenchmarkS2BStd-16 66711826 17.61 ns/op 48 B/op 1 allocs/op
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*/
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// B2S converts byte slice to a string without memory allocation.
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// See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .
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//
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// Note it may break if string and/or slice header will change
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// in the future go versions.
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func B2S(b []byte) string {
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/* #nosec G103 */
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return *(*string)(unsafe.Pointer(&b))
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}
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// S2B converts string to a byte slice without memory allocation.
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//
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// Note it may break if string and/or slice header will change
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// in the future go versions.
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func S2B(s string) (b []byte) {
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/* #nosec G103 */
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bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
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/* #nosec G103 */
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sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
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bh.Data = sh.Data
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bh.Cap = sh.Len
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bh.Len = sh.Len
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return b
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}
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