mirror of
https://github.com/matrix-construct/construct
synced 2024-10-31 19:08:59 +01:00
176 lines
4.5 KiB
C++
176 lines
4.5 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_VECTOR_VIEW_H
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namespace ircd
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{
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template<class T> struct vector_view;
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template<class T> bool empty(const vector_view<T> &) noexcept;
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template<class T> size_t size(const vector_view<T> &) noexcept;
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template<class T> T *data(const vector_view<T> &) noexcept;
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}
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/// Template to represent a contiguous vector or array in a generic way.
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template<class T>
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struct ircd::vector_view
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{
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using value_type = T;
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using pointer = value_type *;
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using reference = value_type &;
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using difference_type = size_t;
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using iterator = value_type *;
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using const_iterator = const value_type *;
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pointer _data { nullptr };
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pointer _stop { nullptr };
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public:
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constexpr pointer data() const noexcept { return _data; }
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constexpr size_t size() const noexcept { return std::distance(_data, _stop); }
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constexpr bool empty() const noexcept { return !size(); }
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const_iterator begin() const noexcept { return data(); }
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const_iterator end() const noexcept { return _stop; }
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const_iterator cbegin() noexcept { return data(); }
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const_iterator cend() noexcept { return _stop; }
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iterator begin() noexcept { return data(); }
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iterator end() noexcept { return _stop; }
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// Bounds check in debug only.
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reference operator[](const size_t &pos) const noexcept
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{
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assert(pos < size());
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return *(data() + pos);
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}
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// Bounds check at runtime.
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reference at(const size_t &pos) const
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{
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if(unlikely(pos >= size()))
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throw std::out_of_range
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{
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"vector_view::range_check"
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};
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return operator[](pos);
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}
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reference back() const
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{
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return at(size() - 1);
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}
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reference front() const
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{
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return at(0);
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}
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constexpr
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vector_view(const pointer __restrict__ start, const pointer __restrict__ stop)
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noexcept
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:_data{start}
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,_stop{stop}
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{}
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constexpr
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vector_view(const pointer __restrict__ start, const size_t size)
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noexcept
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:vector_view(start, start + size)
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{}
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constexpr
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vector_view(const vector_view<value_type> &start, const size_t &size)
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noexcept
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:vector_view(start.data(), std::min(start.size(), size))
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{}
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constexpr
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vector_view(const std::initializer_list<value_type> &list)
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noexcept
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:vector_view(std::begin(list), std::end(list))
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{}
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template<class U,
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class A>
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vector_view(const std::vector<U, A> &v)
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noexcept
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:vector_view(v.data(), v.size())
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{}
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template<class U,
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class A>
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vector_view(std::vector<U, A> &v)
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noexcept
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:vector_view(v.data(), v.size())
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{}
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template<size_t SIZE>
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constexpr
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vector_view(value_type (&__restrict__ buffer)[SIZE])
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noexcept
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:vector_view(buffer, SIZE)
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{}
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template<class U,
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size_t SIZE>
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constexpr
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vector_view(const std::array<U, SIZE> &array)
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noexcept
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:vector_view(const_cast<pointer>(array.data()), array.size())
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{}
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template<size_t SIZE>
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constexpr
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vector_view(std::array<value_type, SIZE> &array)
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noexcept
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:vector_view(array.data(), array.size())
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{}
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// Required for reasonable implicit const conversion of value_type.
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constexpr
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vector_view(const vector_view<typename std::remove_const<value_type>::type> &v)
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noexcept
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:vector_view(v.data(), v.size())
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{}
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vector_view() noexcept = default;
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wdeprecated-copy"
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vector_view &operator=(const vector_view &) noexcept = default;
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#pragma GCC diagnostic pop
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};
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template<class T>
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inline T *
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ircd::data(const vector_view<T> &v)
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noexcept
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{
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return v.data();
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}
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template<class T>
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inline size_t
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ircd::size(const vector_view<T> &v)
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noexcept
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{
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return v.size();
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}
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template<class T>
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inline bool
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ircd::empty(const vector_view<T> &v)
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noexcept
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{
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return v.empty();
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}
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