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