libgo/go/strings/clone.go

   1 // Copyright 2021 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package strings
   6
   7 import (
   8         "unsafe"
   9 )
  10
  11 // Clone returns a fresh copy of s.
  12 // It guarantees to make a copy of s into a new allocation,
  13 // which can be important when retaining only a small substring
  14 // of a much larger string. Using Clone can help such programs
  15 // use less memory. Of course, since using Clone makes a copy,
  16 // overuse of Clone can make programs use more memory.
  17 // Clone should typically be used only rarely, and only when
  18 // profiling indicates that it is needed.
  19 // For strings of length zero the string "" will be returned
  20 // and no allocation is made.
  21 func Clone(s string) string {
  22         if len(s) == 0 {
  23                 return ""
  24         }
  25         b := make([]byte, len(s))
  26         copy(b, s)
  27         return *(*string)(unsafe.Pointer(&b))
  28 }