50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
// +build unsafe
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// Copyright (c) 2012-2015 Ugorji Nwoke. All rights reserved.
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// Use of this source code is governed by a MIT license found in the LICENSE file.
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package codec
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import (
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"unsafe"
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)
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// This file has unsafe variants of some helper methods.
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type unsafeString struct {
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Data uintptr
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Len int
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}
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type unsafeSlice struct {
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Data uintptr
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Len int
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Cap int
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}
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// stringView returns a view of the []byte as a string.
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// In unsafe mode, it doesn't incur allocation and copying caused by conversion.
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// In regular safe mode, it is an allocation and copy.
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func stringView(v []byte) string {
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if len(v) == 0 {
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return ""
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}
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bx := (*unsafeSlice)(unsafe.Pointer(&v))
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sx := unsafeString{bx.Data, bx.Len}
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return *(*string)(unsafe.Pointer(&sx))
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}
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// bytesView returns a view of the string as a []byte.
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// In unsafe mode, it doesn't incur allocation and copying caused by conversion.
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// In regular safe mode, it is an allocation and copy.
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func bytesView(v string) []byte {
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if len(v) == 0 {
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return zeroByteSlice
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}
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sx := (*unsafeString)(unsafe.Pointer(&v))
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bx := unsafeSlice{sx.Data, sx.Len, sx.Len}
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return *(*[]byte)(unsafe.Pointer(&bx))
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}
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