138 lines
4.8 KiB
C++
138 lines
4.8 KiB
C++
#pragma once
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/*
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* Copyright (C) 2024 Brett Terpstra
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#ifndef BLT_ITERATOR_ENUMERATE_H
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#define BLT_ITERATOR_ENUMERATE_H
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#include <blt/iterator/common.h>
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#include <tuple>
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namespace blt
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{
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namespace iterator
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{
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/**
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* struct which is returned by the enumerator.
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* @tparam T type to store.
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*/
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template<typename T>
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struct enumerate_item
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{
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blt::size_t index;
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T value;
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};
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template<typename Iter>
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class enumerate_wrapper : public passthrough_wrapper<Iter, enumerate_wrapper<Iter>>
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{
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public:
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enumerate_wrapper(blt::size_t index, Iter iter): passthrough_wrapper<Iter, enumerate_wrapper<Iter>>(std::move(iter)), index(index)
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{}
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using iterator_category = typename std::iterator_traits<Iter>::iterator_category;
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using value_type = enumerate_item<meta::deref_return_t<Iter>>;
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using difference_type = blt::ptrdiff_t;
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using pointer = value_type;
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using reference = value_type;
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enumerate_item<meta::deref_return_t<Iter>> operator*() const
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{
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return {index, *this->iter};
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}
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enumerate_wrapper& operator++()
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{
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++index;
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++this->iter;
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return *this;
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}
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enumerate_wrapper& operator--()
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{
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--index;
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--this->iter;
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return *this;
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}
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friend enumerate_wrapper operator+(const enumerate_wrapper& a, blt::ptrdiff_t n)
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{
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static_assert(meta::is_random_access_iterator_v<Iter>, "Iterator must allow random access");
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auto copy = a;
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copy.index += n;
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copy.iter = copy.iter + n;
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return copy;
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}
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friend enumerate_wrapper operator-(const enumerate_wrapper& a, blt::ptrdiff_t n)
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{
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static_assert(meta::is_random_access_iterator_v<Iter>, "Iterator must allow random access");
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auto copy = a;
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copy.index -= n;
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copy.iter = copy.iter - n;
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return copy;
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}
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private:
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blt::size_t index;
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};
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}
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template<typename Iter>
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class enumerate_iterator_container : public iterator::iterator_container<iterator::enumerate_wrapper<Iter>>
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{
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public:
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using iterator::iterator_container<iterator::enumerate_wrapper<Iter>>::iterator_container;
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enumerate_iterator_container(Iter begin, Iter end, blt::size_t size):
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iterator::iterator_container<iterator::enumerate_wrapper<Iter>>(
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iterator::enumerate_wrapper<Iter>{0, std::move(begin)}, iterator::enumerate_wrapper<Iter>{size, std::move(end)})
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{}
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};
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template<typename Iter>
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enumerate_iterator_container(Iter, Iter, blt::size_t) -> enumerate_iterator_container<Iter>;
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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 enumerate_iterator_container{container.begin(), container.end(), container.size()};
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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 enumerate_iterator_container{container.begin(), container.end(), container.size()};
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}
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template<typename T, blt::size_t size>
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static inline auto enumerate(const T(& container)[size])
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{
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return enumerate_iterator_container{&container[0], &container[size], size};
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}
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template<typename T, blt::size_t size>
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static inline auto enumerate(T(& container)[size])
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{
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return enumerate_iterator_container{&container[0], &container[size], size};
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}
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}
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#endif //BLT_ITERATOR_ENUMERATE_H
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