forked from premiere/premiere-libtorrent
114 lines
3.4 KiB
C++
114 lines
3.4 KiB
C++
/*
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Copyright (c) 2016, Arvid Norberg
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All rights reserved.
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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
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are met:
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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 copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_SPAN_HPP_INCLUDED
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#define TORRENT_SPAN_HPP_INCLUDED
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#include <vector>
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#include <array>
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#include <type_traits> // for std::is_convertible
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#include "libtorrent/assert.hpp"
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namespace libtorrent
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{
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template <typename T>
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struct span
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{
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span() : m_ptr(nullptr), m_len(0) {}
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template <typename U>
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span(span<U> const& v)
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: m_ptr(v.data()), m_len(v.size()) {}
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span(T& p) : m_ptr(&p), m_len(1) {}
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span(T* p, size_t l) : m_ptr(p), m_len(l) {}
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template <typename U, size_t N>
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span(std::array<U, N>& arr)
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: m_ptr(arr.data()), m_len(arr.size()) {}
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template <typename U, size_t N>
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span(U (&arr)[N])
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: m_ptr(&arr[0]), m_len(N) {}
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// anything with a .data() member function is considered a container
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template <typename Cont, typename = decltype(std::declval<Cont>().data())>
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span(Cont& c)
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: m_ptr(c.data()), m_len(c.size()) {}
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size_t size() const { return m_len; }
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bool empty() const { return m_len == 0; }
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T* data() const { return m_ptr; }
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using iterator = T*;
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using reverse_iterator = std::reverse_iterator<T*>;
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T* begin() const { return m_ptr; }
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T* end() const { return m_ptr + m_len; }
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reverse_iterator rbegin() const { return reverse_iterator(end()); }
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reverse_iterator rend() const { return reverse_iterator(begin()); }
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T& front() const { TORRENT_ASSERT(m_len > 0); return m_ptr[0]; }
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T& back() const { TORRENT_ASSERT(m_len > 0); return m_ptr[m_len-1]; }
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span<T> first(size_t const n) const
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{
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TORRENT_ASSERT(size() >= n);
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return { data(), size() - n };
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}
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span<T> last(size_t const n) const
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{
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TORRENT_ASSERT(size() >= n);
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return { data() + size() - n, n };
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}
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span<T> cut_first(size_t const n) const
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{
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TORRENT_ASSERT(size() >= n);
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return { data() + n, int(size()) - n };
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}
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T& operator[](size_t const idx)
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{
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TORRENT_ASSERT(idx < m_len);
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return m_ptr[idx];
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}
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private:
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T* m_ptr;
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size_t m_len;
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};
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}
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#endif // TORRENT_SPAN_HPP_INCLUDED
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