534 lines
18 KiB
C++
534 lines
18 KiB
C++
#pragma once
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/*
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* Created by Brett on 06/02/24.
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* Licensed under GNU General Public License V3.0
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* See LICENSE file for license detail
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*/
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#ifndef BLT_RANGES_H
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#define BLT_RANGES_H
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#include <blt/std/types.h>
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#include <type_traits>
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#include <iterator>
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#include <memory>
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#include <utility>
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#include <limits>
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namespace blt
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{
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namespace itr
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{
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template<typename TYPE_ITR, bool is_ptr = std::is_pointer_v<TYPE_ITR>>
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class iterator;
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template<typename TYPE_ITR>
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class iterator<TYPE_ITR, false>
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{
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public:
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using iterator_category = std::input_iterator_tag;
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using value_type = typename TYPE_ITR::value_type;
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using difference_type = typename TYPE_ITR::difference_type;
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using pointer = typename TYPE_ITR::pointer;
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using reference = typename TYPE_ITR::reference;
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using const_reference = const typename TYPE_ITR::reference;
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private:
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blt::size_t index = 0;
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TYPE_ITR current;
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public:
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explicit iterator(TYPE_ITR current): current(std::move(current))
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{}
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iterator& operator++()
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{
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++index;
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++current;
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return *this;
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}
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bool operator==(iterator other) const
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{
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return current == other.current;
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}
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bool operator!=(iterator other) const
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{
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return current != other.current;
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}
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std::pair<blt::size_t, const_reference> operator*() const
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{
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return {index, *current};
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};
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std::pair<blt::size_t, reference> operator*()
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{
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return {index, *current};
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};
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};
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template<typename TYPE_ITR>
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class iterator<TYPE_ITR, true>
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{
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public:
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using iterator_category = std::input_iterator_tag;
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using value_type = std::remove_pointer_t<TYPE_ITR>;
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using difference_type = std::ptrdiff_t;
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using pointer = TYPE_ITR;
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using reference = std::remove_pointer_t<TYPE_ITR>&;
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using const_reference = const std::remove_pointer_t<TYPE_ITR>&;
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private:
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blt::size_t index = 0;
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TYPE_ITR current;
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public:
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explicit iterator(TYPE_ITR current): current(std::move(current))
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{}
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iterator& operator++()
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{
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++index;
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++current;
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return *this;
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}
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bool operator==(iterator other) const
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{
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return current == other.current;
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}
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bool operator!=(iterator other) const
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{
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return current != other.current;
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}
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std::pair<blt::size_t, const_reference> operator*() const
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{
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return {index, *current};
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};
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std::pair<blt::size_t, reference> operator*()
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{
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return {index, *current};
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};
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};
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}
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template<typename TYPE_ITR>
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class enumerator
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{
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public:
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explicit enumerator(TYPE_ITR begin, TYPE_ITR end): begin_(std::move(begin)), end_(std::move(end))
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{}
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itr::iterator<TYPE_ITR> begin()
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{
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return begin_;
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}
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itr::iterator<TYPE_ITR> end()
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{
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return end_;
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}
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private:
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itr::iterator<TYPE_ITR> begin_;
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itr::iterator<TYPE_ITR> end_;
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};
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template<typename T>
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static inline auto enumerate(const T& container)
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{
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return enumerator{container.begin(), container.end()};
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}
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template<typename T>
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static inline auto enumerate(T& container)
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{
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return enumerator{container.begin(), container.end()};
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}
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template<typename T>
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static inline auto enumerate(T&& container)
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{
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return enumerator{container.begin(), container.end()};
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}
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template<typename T>
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struct range
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{
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public:
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struct range_itr
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{
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public:
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using iterator_category = std::bidirectional_iterator_tag;
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using difference_type = T;
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using value_type = T;
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using pointer = T*;
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using reference = T&;
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private:
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T current;
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bool forward;
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public:
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explicit range_itr(T current, bool forward): current(current), forward(forward)
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{}
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value_type operator*() const
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{ return current; }
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value_type operator->()
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{ return current; }
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range_itr& operator++()
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{
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if (forward)
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current++;
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else
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current--;
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return *this;
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}
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range_itr& operator--()
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{
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if (forward)
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current--;
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else
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current++;
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return *this;
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}
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friend bool operator==(const range_itr& a, const range_itr& b)
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{
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return a.current == b.current;
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}
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friend bool operator!=(const range_itr& a, const range_itr& b)
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{
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return a.current != b.current;
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}
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};
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private:
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T _begin;
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T _end;
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T offset = 0;
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public:
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range(T begin, T end): _begin(begin), _end(end), offset(end < begin ? 1 : 0)
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{}
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range_itr begin()
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{
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return range_itr(_begin - offset, offset == 0);
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}
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range_itr end()
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{
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// not sure if i like this
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return range_itr(_end - offset, offset == 0);
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}
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};
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template<typename I>
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class itr_offset
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{
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private:
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I begin_;
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I end_;
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public:
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template<typename T>
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itr_offset(I begin, I end, T offset): begin_(begin), end_(end)
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{
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for (T t = 0; t < offset; t++)
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++begin_;
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}
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template<typename C, typename T>
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itr_offset(C& container, T offset): begin_(container.begin()), end_(container.end())
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{
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for (T t = 0; t < offset; t++)
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++begin_;
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}
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auto begin()
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{
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return begin_;
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}
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auto end()
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{
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return end_;
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}
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};
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template<typename C, typename T>
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itr_offset(C, T) -> itr_offset<typename C::iterator>;
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inline constexpr std::size_t dynamic_extent = std::numeric_limits<std::size_t>::max();
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template<typename T, std::size_t extent = dynamic_extent>
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class span;
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// https://codereview.stackexchange.com/questions/217814/c17-span-implementation
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namespace span_detail
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{
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// detect specializations of span
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template<class T>
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struct is_span : std::false_type
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{
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};
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template<class T, std::size_t N>
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struct is_span<span<T, N>> : std::true_type
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{
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};
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template<class T>
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inline constexpr bool is_span_v = is_span<T>::value;
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// detect specializations of std::array
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template<class T>
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struct is_array : std::false_type
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{
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};
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template<class T, std::size_t N>
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struct is_array<std::array<T, N>> : std::true_type
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{
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};
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template<class T>
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inline constexpr bool is_array_v = is_array<T>::value;
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// detect container
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template<class C, class = void>
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struct is_cont : std::false_type
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{
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};
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template<class C>
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struct is_cont<C,
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std::void_t<
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std::enable_if_t<!is_span_v<C>>,
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std::enable_if_t<!is_array_v<C>>,
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std::enable_if_t<!std::is_array_v<C>>,
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decltype(data(std::declval<C>())),
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decltype(size(std::declval<C>()))
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>> : std::true_type
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{
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};
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template<class C>
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inline constexpr bool is_cont_v = is_cont<C>::value;
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}
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template<typename T, std::size_t extent>
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class span
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{
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public:
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using element_type = T;
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using value_type = std::remove_cv_t<T>;
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using size_type = blt::size_t;
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using difference_type = std::ptrdiff_t;
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using pointer = T*;
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using const_pointer = const T*;
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using reference = T&;
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using const_reference = const T&;
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using iterator = T*;
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using const_iterator = const T*;
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using reverse_iterator = std::reverse_iterator<iterator>;
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using const_reverse_iterator = std::reverse_iterator<const_iterator>;
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private:
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size_type size_;
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pointer data_;
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public:
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constexpr span() noexcept: size_(0), data_(nullptr)
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{}
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template<class It, std::size_t SIZE, typename std::enable_if_t<extent != dynamic_extent && SIZE == extent, bool> = true>
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constexpr explicit span(It first, size_type count): size_(count), data_(&*first)
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{}
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template<class It, std::size_t SIZE, typename std::enable_if_t<extent == dynamic_extent && SIZE == extent, bool> = true>
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constexpr span(It first, size_type count): size_(count), data_(&*first)
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{}
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template<class It, class End, std::size_t SIZE, typename std::enable_if_t<extent != dynamic_extent && SIZE == extent, bool> = true>
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constexpr explicit span(It first, End last): size_(&*last - &*first), data_(&*first)
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{}
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template<class It, class End, std::size_t SIZE, typename std::enable_if_t<extent == dynamic_extent && SIZE == extent, bool> = true>
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constexpr span(It first, End last): size_(&*last - &*first), data_(&*first)
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{}
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template<std::size_t N, typename std::enable_if_t<(N == dynamic_extent || N == extent) &&
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(std::is_convertible_v<std::remove_pointer_t<decltype(
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std::data(std::declval<T(&)[N]>()))>(*)[], T(*)[]>), bool> = true>
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constexpr span(element_type (& arr)[N]) noexcept: size_{N}, data_{arr}
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{}
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template<class U, std::size_t N, typename std::enable_if_t<(N == dynamic_extent || N == extent) &&
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(std::is_convertible_v<std::remove_pointer_t<decltype(
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std::data(std::declval<T(&)[N]>()))>(*)[], T(*)[]>), bool> = true>
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constexpr span(std::array<U, N>& arr) noexcept: size_(N), data_{arr.data()}
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{}
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template<class U, std::size_t N, typename std::enable_if_t<(N == dynamic_extent || N == extent) &&
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(std::is_convertible_v<std::remove_pointer_t<decltype(
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std::data(std::declval<T(&)[N]>()))>(*)[], T(*)[]>), bool> = true>
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constexpr span(const std::array<U, N>& arr) noexcept: size_(N), data_{arr.data()}
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{}
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template<class R, class RCV = std::remove_cv_t<std::remove_reference_t<R>>, typename std::enable_if_t<
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extent != dynamic_extent && span_detail::is_cont_v<RCV> &&
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std::is_convertible_v<std::remove_pointer_t<decltype(std::data(std::declval<R>()))>(*)[], T(*)[]>, bool> = true>
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explicit constexpr span(R&& range): size_(std::size(range)), data_(std::data(range))
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{}
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template<class R, class RCV = std::remove_cv_t<std::remove_reference_t<R>>, typename std::enable_if_t<
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extent == dynamic_extent && span_detail::is_cont_v<RCV> &&
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std::is_convertible_v<std::remove_pointer_t<decltype(std::data(std::declval<R>()))>(*)[], T(*)[]>, bool> = true>
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constexpr span(R&& range): size_(std::size(range)), data_(std::data(range))
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{}
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template<size_type SIZE, typename std::enable_if_t<
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extent != dynamic_extent && SIZE == extent && std::is_const_v<element_type>, bool> = true>
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explicit constexpr span(std::initializer_list<value_type> il) noexcept: size_(il.size()), data_(&il.begin())
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{}
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template<size_type SIZE, typename std::enable_if_t<
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extent == dynamic_extent && SIZE == extent && std::is_const_v<element_type>, bool> = true>
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explicit span(std::initializer_list<value_type> il) noexcept: size_(il.size()), data_(&il.begin())
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{}
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template<class U, std::size_t N, typename std::enable_if_t<
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extent != dynamic_extent && N == dynamic_extent && std::is_convertible_v<U(*)[], T(*)[]>, bool> = true>
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explicit constexpr span(const span<U, N>& source) noexcept: size_{source.size()}, data_{source.data()}
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{}
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template<class U, std::size_t N, typename std::enable_if_t<
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!(extent != dynamic_extent && N == dynamic_extent) && std::is_convertible_v<U(*)[], T(*)[]>, bool> = true>
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constexpr span(const span<U, N>& source) noexcept: size_{source.size()}, data_{source.data()}
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{}
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constexpr span(const span& other) noexcept = default;
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constexpr iterator begin() const noexcept
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{
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return data();
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}
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constexpr iterator end() const noexcept
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{
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return data() + size();
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}
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constexpr const_iterator cbegin() const noexcept
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{
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return data();
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}
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constexpr const_iterator cend() const noexcept
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{
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return data() + size();
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}
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constexpr reverse_iterator rbegin() const noexcept
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{
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return reverse_iterator{end()};
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}
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constexpr reverse_iterator rend() const noexcept
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{
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return reverse_iterator{begin()};
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}
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constexpr const_reverse_iterator crbegin() const noexcept
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{
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return reverse_iterator{cend()};
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}
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constexpr const_reverse_iterator crend() const noexcept
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{
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return reverse_iterator{cbegin()};
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}
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friend constexpr iterator begin(span s) noexcept
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{
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return s.begin();
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}
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friend constexpr iterator end(span s) noexcept
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{
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return s.end();
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}
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[[nodiscard]] constexpr size_type size() const noexcept
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{
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return size_;
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}
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[[nodiscard]] constexpr size_type size_bytes() const noexcept
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{
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return size() * sizeof(T);
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}
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[[nodiscard]] constexpr bool empty() const noexcept
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{
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return size() == 0;
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}
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constexpr reference operator[](size_type idx) const
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{
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return *(data() + idx);
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}
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constexpr reference front() const
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{
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return *data();
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}
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constexpr reference back() const
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{
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return *(data() + (size() - 1));
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}
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constexpr pointer data() const noexcept
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{
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return data_;
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}
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constexpr span<T, dynamic_extent> first(size_type cnt) const
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{
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return {data(), cnt};
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}
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constexpr span<T, dynamic_extent> last(size_type cnt) const
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{
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return {data() + (size() - cnt), cnt};
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}
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constexpr span<T, dynamic_extent> subspan(size_type off, size_type cnt = dynamic_extent) const
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{
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return {data() + off, cnt == dynamic_extent ? size() - off : cnt};
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}
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};
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template<class T, std::size_t N>
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span(T (&)[N]) -> span<T, N>;
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template<class T, std::size_t N>
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span(std::array<T, N>&) -> span<T, N>;
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template<class T, std::size_t N>
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span(const std::array<T, N>&) -> span<const T, N>;
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template<class Cont>
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span(Cont&) -> span<typename Cont::value_type>;
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template<class Cont>
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span(const Cont&) -> span<const typename Cont::value_type>;
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}
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#endif //BLT_RANGES_H
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