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/* -*- 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_SPAN_HXX
#define INCLUDED_O3TL_SPAN_HXX
#include <sal/config.h>
#include <config_global.h>
#if HAVE_CPP_SPAN
#include <span>
namespace o3tl { using std::span; }
#else
#include <cassert>
#include <cstddef>
#include <iterator>
#include <type_traits>
#include <vector>
namespace o3tl {
/** A barebones approximation of C++20 <span>.
*/
template<typename T>
class span {
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 = pointer;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = std::reverse_iterator<iterator>;
using size_type = std::size_t;
using difference_type = std::ptrdiff_t;
constexpr span() noexcept : data_(nullptr), size_(0) {}
template<std::size_t N>
constexpr span (T (&a)[N]) noexcept : data_(a), size_(N) {}
constexpr span (T *a, size_type len) noexcept
: data_(a), size_(len)
{
// not terribly sure about this, might need to strengthen it
assert(a != nullptr || len == 0);
}
template<typename T2>
constexpr span(const std::vector<T2>& vec)
: data_(vec.data()), size_(vec.size()) {}
/** for assigning from span<T> to span<const T> */
constexpr span (const span<typename std::remove_const<T>::type>& other) noexcept
: data_(other.data()), size_(other.size()) {}
constexpr bool empty() const noexcept { return size_ == 0; }
constexpr iterator begin() const noexcept { return data_; }
constexpr iterator end() const noexcept { return begin() + size(); }
reverse_iterator rbegin() const noexcept
{ return reverse_iterator(end()); }
reverse_iterator rend() const noexcept
{ return reverse_iterator(begin()); }
constexpr size_type size() const noexcept { return size_; }
constexpr reference operator [](size_type pos) const {
assert(pos < size());
return data_[pos];
}
constexpr pointer data() const noexcept { return data_; }
private:
pointer data_;
size_type size_;
};
} // namespace o3tl
#endif
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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