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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_ArenaAllocatorExtensions_h
#define mozilla_ArenaAllocatorExtensions_h
#include "mozilla/ArenaAllocator.h"
#include "mozilla/CheckedInt.h"
#include "nsAString.h"
/**
* Extensions to the ArenaAllocator class.
*/
namespace mozilla {
namespace detail {
template <typename T, size_t ArenaSize, size_t Alignment>
T* DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
ArenaAllocator<ArenaSize, Alignment>& aArena);
} // namespace detail
/**
* Makes an arena allocated null-terminated copy of the source string. The
* source string must be null-terminated.
*
* @param aSrc String to copy.
* @param aArena The arena to allocate the string copy out of.
* @return An arena allocated null-terminated string.
*/
template <typename T, size_t ArenaSize, size_t Alignment>
T* ArenaStrdup(const T* aStr, ArenaAllocator<ArenaSize, Alignment>& aArena) {
return detail::DuplicateString(aStr, nsCharTraits<T>::length(aStr), aArena);
}
/**
* Makes an arena allocated null-terminated copy of the source string.
*
* @param aSrc String to copy.
* @param aArena The arena to allocate the string copy out of.
* @return An arena allocated null-terminated string.
*/
template <typename T, size_t ArenaSize, size_t Alignment>
T* ArenaStrdup(const detail::nsTStringRepr<T>& aStr,
ArenaAllocator<ArenaSize, Alignment>& aArena) {
return detail::DuplicateString(aStr.BeginReading(), aStr.Length(), aArena);
}
/**
* Copies the source string and adds a null terminator. Source string does not
* have to be null terminated.
*/
template <typename T, size_t ArenaSize, size_t Alignment>
T* detail::DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
ArenaAllocator<ArenaSize, Alignment>& aArena) {
const auto byteLen = (aLen + 1) * sizeof(T);
if (!byteLen.isValid()) {
return nullptr;
}
T* p = static_cast<T*>(aArena.Allocate(byteLen.value(), mozilla::fallible));
if (p) {
memcpy(p, aSrc, byteLen.value() - sizeof(T));
p[aLen.value()] = T(0);
}
return p;
}
} // namespace mozilla
#endif // mozilla_ArenaAllocatorExtensions_h