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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef mozilla_ArenaAllocatorExtensions_h
       8             : #define mozilla_ArenaAllocatorExtensions_h
       9             : 
      10             : #include "mozilla/ArenaAllocator.h"
      11             : #include "mozilla/CheckedInt.h"
      12             : #include "nsAString.h"
      13             : 
      14             : /**
      15             :  * Extensions to the ArenaAllocator class.
      16             :  */
      17             : namespace mozilla {
      18             : 
      19             : namespace detail {
      20             : 
      21             : template<typename T, size_t ArenaSize, size_t Alignment>
      22             : T* DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
      23             :                    ArenaAllocator<ArenaSize, Alignment>& aArena);
      24             : 
      25             : } // namespace detail
      26             : 
      27             : /**
      28             :  * Makes an arena allocated null-terminated copy of the source string. The
      29             :  * source string must be null-terminated.
      30             :  *
      31             :  * @param aSrc String to copy.
      32             :  * @param aArena The arena to allocate the string copy out of.
      33             :  * @return An arena allocated null-terminated string.
      34             :  */
      35             : template<size_t ArenaSize, size_t Alignment>
      36       10108 : char* ArenaStrdup(const char* aStr,
      37             :                   ArenaAllocator<ArenaSize, Alignment>& aArena)
      38             : {
      39       10108 :   return detail::DuplicateString(aStr, strlen(aStr), aArena);
      40             : }
      41             : 
      42             : /**
      43             :  * Makes an arena allocated null-terminated copy of the source string.
      44             :  *
      45             :  * @param aSrc String to copy.
      46             :  * @param aArena The arena to allocate the string copy out of.
      47             :  * @return An arena allocated null-terminated string.
      48             :  */
      49             : template<size_t ArenaSize, size_t Alignment>
      50        1300 : nsAString::char_type* ArenaStrdup(
      51             :     const nsAString& aStr, ArenaAllocator<ArenaSize, Alignment>& aArena)
      52             : {
      53        1300 :   return detail::DuplicateString(aStr.BeginReading(), aStr.Length(), aArena);
      54             : }
      55             : 
      56             : /**
      57             :  * Makes an arena allocated null-terminated copy of the source string.
      58             :  *
      59             :  * @param aSrc String to copy.
      60             :  * @param aArena The arena to allocate the string copy out of.
      61             :  * @return An arena allocated null-terminated string.
      62             :  */
      63             : template<size_t ArenaSize, size_t Alignment>
      64        1300 : nsACString::char_type* ArenaStrdup(
      65             :     const nsACString& aStr, ArenaAllocator<ArenaSize, Alignment>& aArena)
      66             : {
      67        1300 :   return detail::DuplicateString(aStr.BeginReading(), aStr.Length(), aArena);
      68             : }
      69             : 
      70             : /**
      71             :  * Copies the source string and adds a null terminator. Source string does not
      72             :  * have to be null terminated.
      73             :  */
      74             : template<typename T, size_t ArenaSize, size_t Alignment>
      75       12708 : T* detail::DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
      76             :                            ArenaAllocator<ArenaSize, Alignment>& aArena)
      77             : {
      78       12708 :   const auto byteLen = (aLen + 1) * sizeof(T);
      79       12708 :   if (!byteLen.isValid()) {
      80           0 :     return nullptr;
      81             :   }
      82             : 
      83       12708 :   T* p = static_cast<T*>(aArena.Allocate(byteLen.value(), mozilla::fallible));
      84       12708 :   if (p) {
      85       12708 :     memcpy(p, aSrc, byteLen.value() - sizeof(T));
      86       12708 :     p[aLen.value()] = T(0);
      87             :   }
      88             : 
      89       12708 :   return p;
      90             : }
      91             : 
      92             : } // namespace mozilla
      93             : 
      94             : #endif // mozilla_ArenaAllocatorExtensions_h