70 lines
2.0 KiB
C++
70 lines
2.0 KiB
C++
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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2020, Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include <iterator>
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namespace cruft::iterator {
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///////////////////////////////////////////////////////////////////////////
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/// An iterator that converts the value_type of an underlying iterator to
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/// a requested type.
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template <typename ValueT, typename IteratorT>
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class cast {
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public:
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cast (IteratorT _inner)
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: m_inner (_inner)
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{ ; }
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using iterator_category = typename std::iterator_traits<IteratorT>::iterator_category;
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using value_type = ValueT;
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using difference_type = typename std::iterator_traits<IteratorT>::difference_type;
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using pointer = value_type*;
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using reference = value_type&;
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class wrapper {
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public:
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using inner_value = typename std::iterator_traits<IteratorT>::value;
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using inner_pointer = typename std::iterator_traits<IteratorT>::pointer;
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using inner_reference = typename std::iterator_traits<IteratorT>::reference;
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reference
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operator= (ValueT const &val)
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{
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_value = static_cast<inner_value> (val);
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return _value;
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}
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reference operator= (ValueT &&val)
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{
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_value = static_cast<inner_value> (val);
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}
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inner_pointer
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operator-> ()
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{ return &_value; }
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private:
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inner_reference _value;
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};
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wrapper operator* (void) { return wrapper (*m_inner); };
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wrapper operator-> (void) { return wrapper (*m_inner); };
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cast& operator++ (void)
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{
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++m_inner;
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return *this;
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}
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private:
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IteratorT m_inner;
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};
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}
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