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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:06:44 +0000
commited5640d8b587fbcfed7dd7967f3de04b37a76f26 (patch)
tree7a5f7c6c9d02226d7471cb3cc8fbbf631b415303 /include/o3tl/span.hxx
parentInitial commit. (diff)
downloadlibreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.tar.xz
libreoffice-ed5640d8b587fbcfed7dd7967f3de04b37a76f26.zip
Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/o3tl/span.hxx')
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diff --git a/include/o3tl/span.hxx b/include/o3tl/span.hxx
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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: */