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Diffstat (limited to 'include/o3tl')
| -rw-r--r-- | include/o3tl/array_view.hxx | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/include/o3tl/array_view.hxx b/include/o3tl/array_view.hxx new file mode 100644 index 000000000000..9da86866680e --- /dev/null +++ b/include/o3tl/array_view.hxx @@ -0,0 +1,169 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * 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 INCLUDED_O3TL_ARRAY_VIEW_HXX +#define INCLUDED_O3TL_ARRAY_VIEW_HXX + +#include <sal/config.h> + +#include <algorithm> +#include <cstddef> +#include <ios> +#include <iterator> +#include <ostream> +#include <stdexcept> +#include <string> +#include <type_traits> +#include <utility> + +#include <config_global.h> +#include <rtl/string.hxx> +#include <rtl/ustring.hxx> +#include <sal/types.h> + +// A barebones approximation of C++17(?) <array_view>, haven't bothered with more than single-dimensional arrays + +#if HAVE_CXX14_CONSTEXPR +#define CONSTEXPR constexpr +#else +#define CONSTEXPR +#endif + +namespace o3tl { + +#if defined _MSC_VER +#pragma warning(push, 1) +#pragma warning(disable: 4814) // in C++14 'constexpr' will not imply 'const' +#endif + +template<typename T> +class array_view { +public: + using value_type = T; + using pointer = value_type *; + using const_pointer = value_type const *; + using reference = value_type &; + using const_reference = value_type const &; + using const_iterator = const_pointer; + using iterator = const_iterator; + using const_reverse_iterator = std::reverse_iterator<const_iterator>; + using reverse_iterator = const_reverse_iterator; + using size_type = std::size_t; + using difference_type = std::ptrdiff_t; + + static constexpr size_type npos = size_type(-1); + + constexpr array_view() noexcept : data_(nullptr), size_(0) {} + + template<size_type N> + CONSTEXPR array_view (T const (&a)[N]) noexcept : data_(a), size_(N) {} + + CONSTEXPR array_view (T const *a, size_type len) noexcept + : data_(a), size_(len) + { +#if HAVE_CXX14_CONSTEXPR + // not terribly sure about this, might need to relax it + assert((a == nullptr && len == 0) || (a != nullptr && len > 0)); +#endif + } + + constexpr bool empty() const noexcept { return size_ == 0; } + + constexpr const_iterator begin() const noexcept { return data_; } + constexpr const_iterator end() const noexcept { return begin() + size(); } + + constexpr const_iterator cbegin() const noexcept { return begin(); } + constexpr const_iterator cend() const noexcept { return end(); } + + constexpr const_reverse_iterator rbegin() const noexcept + { return const_reverse_iterator(end()); } + constexpr const_reverse_iterator rend() const noexcept + { return const_reverse_iterator(begin()); } + + constexpr const_reverse_iterator crbegin() const noexcept + { return rbegin(); } + constexpr const_reverse_iterator crend() const noexcept { return rend(); } + + constexpr size_type size() const noexcept { return size_; } + constexpr size_type length() const noexcept { return size(); } + +#if !defined __clang__ || HAVE_CXX14_CONSTEXPR + constexpr +#endif + size_type max_size() const noexcept { +#if defined __clang__ // avoid constexpr issues with other, older compilers + (void) this; // loplugin:staticmethods +#endif + return npos - 1; + } + + constexpr const_reference operator [](size_type pos) const { +#if HAVE_CXX14_CONSTEXPR + assert(pos < size()); +#endif + return data_[pos]; + } + + CONSTEXPR + const_reference at(size_type pos) const { + if (pos >= size()) { + throw std::out_of_range("o3tl::array_view::at"); + } + return operator [](pos); + } + + constexpr const_reference front() const { +#if HAVE_CXX14_CONSTEXPR + assert(!empty()); +#endif + return operator [](0); + } + + constexpr const_reference back() const { +#if HAVE_CXX14_CONSTEXPR + assert(!empty()); +#endif + return operator [](size() - 1); + } + + constexpr const_pointer data() const noexcept { return data_; } + + CONSTEXPR void swap(array_view & s) noexcept { + std::swap(data_, s.data_); + std::swap(size_, s.size_); + } + +private: + const_pointer data_; + size_type size_; +}; + + +#if defined _MSC_VER +#pragma warning(pop) +#endif + +} // namespace o3tl + +namespace std { + +template<typename T> +struct hash<o3tl::array_view<T>> { + std::size_t operator()(o3tl::array_view<T> s) + { return hash<T[]>()(s.data(), s.size()); } +}; + +} // namespace std + + +#undef CONSTEXPR + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |