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| 1 | // -*- C++ -*- |
|---|---|
| 2 | //===----------------------------------------------------------------------===// |
| 3 | // |
| 4 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 5 | // See https://llvm.org/LICENSE.txt for license information. |
| 6 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | |
| 10 | #ifndef _LIBCPP___CXX03___MEMORY_TEMPORARY_BUFFER_H |
| 11 | #define _LIBCPP___CXX03___MEMORY_TEMPORARY_BUFFER_H |
| 12 | |
| 13 | #include <__cxx03/__config> |
| 14 | #include <__cxx03/__utility/pair.h> |
| 15 | #include <__cxx03/cstddef> |
| 16 | #include <__cxx03/new> |
| 17 | |
| 18 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 19 | # pragma GCC system_header |
| 20 | #endif |
| 21 | |
| 22 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 23 | |
| 24 | template <class _Tp> |
| 25 | _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI pair<_Tp*, ptrdiff_t> |
| 26 | get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT { |
| 27 | pair<_Tp*, ptrdiff_t> __r(0, 0); |
| 28 | const ptrdiff_t __m = |
| 29 | (~ptrdiff_t(0) ^ ptrdiff_t(ptrdiff_t(1) << (sizeof(ptrdiff_t) * __CHAR_BIT__ - 1))) / sizeof(_Tp); |
| 30 | if (__n > __m) |
| 31 | __n = __m; |
| 32 | while (__n > 0) { |
| 33 | #if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION) |
| 34 | if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp))) { |
| 35 | align_val_t __al = align_val_t(_LIBCPP_ALIGNOF(_Tp)); |
| 36 | __r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), __al, nothrow)); |
| 37 | } else { |
| 38 | __r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow)); |
| 39 | } |
| 40 | #else |
| 41 | if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp))) { |
| 42 | // Since aligned operator new is unavailable, return an empty |
| 43 | // buffer rather than one with invalid alignment. |
| 44 | return __r; |
| 45 | } |
| 46 | |
| 47 | __r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow)); |
| 48 | #endif |
| 49 | |
| 50 | if (__r.first) { |
| 51 | __r.second = __n; |
| 52 | break; |
| 53 | } |
| 54 | __n /= 2; |
| 55 | } |
| 56 | return __r; |
| 57 | } |
| 58 | |
| 59 | template <class _Tp> |
| 60 | inline _LIBCPP_HIDE_FROM_ABI void return_temporary_buffer(_Tp* __p) _NOEXCEPT { |
| 61 | std::__libcpp_deallocate_unsized((void*)__p, _LIBCPP_ALIGNOF(_Tp)); |
| 62 | } |
| 63 | |
| 64 | struct __return_temporary_buffer { |
| 65 | _LIBCPP_SUPPRESS_DEPRECATED_PUSH |
| 66 | template <class _Tp> |
| 67 | _LIBCPP_HIDE_FROM_ABI void operator()(_Tp* __p) const { |
| 68 | std::return_temporary_buffer(__p); |
| 69 | } |
| 70 | _LIBCPP_SUPPRESS_DEPRECATED_POP |
| 71 | }; |
| 72 | |
| 73 | _LIBCPP_END_NAMESPACE_STD |
| 74 | |
| 75 | #endif // _LIBCPP___CXX03___MEMORY_TEMPORARY_BUFFER_H |
| 76 |
Warning: This file is not a C or C++ file. It does not have highlighting.