134 lines
4.5 KiB
C++
134 lines
4.5 KiB
C++
// Copyright (c) 2021 Marshall A. Greenblatt. Portions copyright (c) 2021
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// Google Inc. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the name Chromium Embedded
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// Framework nor the names of its contributors may be used to endorse
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// or promote products derived from this software without specific prior
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// written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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#ifndef CEF_INCLUDE_BASE_CEF_CXX17_BACKPORTS_H_
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#define CEF_INCLUDE_BASE_CEF_CXX17_BACKPORTS_H_
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#pragma once
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#if defined(USING_CHROMIUM_INCLUDES)
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// When building CEF include the Chromium header directly.
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// TODO(cef): Change to "base/cxx17_backports.h" in M93.
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#include "base/stl_util.h"
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#else // !USING_CHROMIUM_INCLUDES
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// The following is substantially similar to the Chromium implementation.
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// If the Chromium implementation diverges the below implementation should be
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// updated to match.
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#include <array>
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#include <initializer_list>
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#include <memory>
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#include <string>
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namespace base {
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// C++14 implementation of C++17's std::size():
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// http://en.cppreference.com/w/cpp/iterator/size
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template <typename Container>
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constexpr auto size(const Container& c) -> decltype(c.size()) {
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return c.size();
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}
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template <typename T, size_t N>
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constexpr size_t size(const T (&array)[N]) noexcept {
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return N;
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}
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// C++14 implementation of C++17's std::empty():
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// http://en.cppreference.com/w/cpp/iterator/empty
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template <typename Container>
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constexpr auto empty(const Container& c) -> decltype(c.empty()) {
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return c.empty();
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}
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template <typename T, size_t N>
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constexpr bool empty(const T (&array)[N]) noexcept {
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return false;
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}
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template <typename T>
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constexpr bool empty(std::initializer_list<T> il) noexcept {
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return il.size() == 0;
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}
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// C++14 implementation of C++17's std::data():
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// http://en.cppreference.com/w/cpp/iterator/data
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template <typename Container>
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constexpr auto data(Container& c) -> decltype(c.data()) {
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return c.data();
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}
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// std::basic_string::data() had no mutable overload prior to C++17 [1].
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// Hence this overload is provided.
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// Note: str[0] is safe even for empty strings, as they are guaranteed to be
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// null-terminated [2].
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//
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// [1] http://en.cppreference.com/w/cpp/string/basic_string/data
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// [2] http://en.cppreference.com/w/cpp/string/basic_string/operator_at
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template <typename CharT, typename Traits, typename Allocator>
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CharT* data(std::basic_string<CharT, Traits, Allocator>& str) {
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return std::addressof(str[0]);
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}
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template <typename Container>
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constexpr auto data(const Container& c) -> decltype(c.data()) {
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return c.data();
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}
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template <typename T, size_t N>
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constexpr T* data(T (&array)[N]) noexcept {
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return array;
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}
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template <typename T>
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constexpr const T* data(std::initializer_list<T> il) noexcept {
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return il.begin();
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}
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// std::array::data() was not constexpr prior to C++17 [1].
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// Hence these overloads are provided.
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//
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// [1] https://en.cppreference.com/w/cpp/container/array/data
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template <typename T, size_t N>
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constexpr T* data(std::array<T, N>& array) noexcept {
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return !array.empty() ? &array[0] : nullptr;
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}
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template <typename T, size_t N>
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constexpr const T* data(const std::array<T, N>& array) noexcept {
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return !array.empty() ? &array[0] : nullptr;
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}
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} // namespace base
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#endif // !USING_CHROMIUM_INCLUDES
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#endif // CEF_INCLUDE_BASE_CEF_CXX17_BACKPORTS_H_
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