96 lines
2.9 KiB
C++
96 lines
2.9 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <http://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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*/
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#pragma once
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#include <inttypes.h>
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#include "dxxsconf.h"
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#include "partial_range.h"
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/*
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* This could have been done using a std::pair, but using a custom type
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* allows for more descriptive member names.
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*/
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template <typename range_value_type, typename index_type>
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struct enumerated_value
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{
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range_value_type &value;
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const index_type idx;
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};
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template <typename range_iterator_type, typename index_type, typename result_type>
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class enumerated_iterator
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{
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range_iterator_type m_iter;
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index_type m_idx;
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public:
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enumerated_iterator(const range_iterator_type &iter, const index_type idx) :
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m_iter(iter), m_idx(idx)
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{
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}
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result_type operator*() const
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{
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return {*m_iter, m_idx};
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}
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enumerated_iterator &operator++()
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{
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++ m_iter;
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++ m_idx;
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return *this;
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}
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bool operator!=(const enumerated_iterator &i) const
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{
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return m_iter != i.m_iter;
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}
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};
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template <typename range_iterator_type, typename index_type>
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class enumerated_range : partial_range_t<range_iterator_type>
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{
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using base_type = partial_range_t<range_iterator_type>;
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using enumerated_iterator_type = enumerated_iterator<range_iterator_type, index_type, enumerated_value<decltype(*std::declval<range_iterator_type>()), index_type>>;
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const index_type m_idx;
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public:
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enumerated_range(const range_iterator_type b, const range_iterator_type e, const index_type i) :
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base_type(b, e), m_idx(i)
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{
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}
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template <typename range_type>
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enumerated_range(range_type &t, const index_type i) :
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base_type(t), m_idx(i)
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{
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}
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enumerated_iterator_type begin() const
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{
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return enumerated_iterator_type(this->base_type::begin(), m_idx);
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}
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enumerated_iterator_type end() const
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{
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return enumerated_iterator_type(this->base_type::end(), 0 /* unused */);
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}
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};
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template <typename range_type, typename index_type = uint_fast32_t, typename range_iterator_type = decltype(begin(std::declval<range_type &>()))>
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static enumerated_range<range_iterator_type, index_type> enumerate(range_type &r, const index_type start = 0)
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{
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return enumerated_range<range_iterator_type, index_type>(r, start);
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}
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/*
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* As a special case, allow rvalue reference to
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* partial_range_t<range_iterator_type>, since partial_range_t does not
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* own the data over which it iterates, and so it does not need to
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* persist past the creation of the enumerated_range.
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*
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* This special case is legal for any temporary range which acts as a
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* view on a persistent sequence.
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*/
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template <typename range_iterator_type, typename index_type = uint_fast32_t>
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static enumerated_range<range_iterator_type, index_type> enumerate(partial_range_t<range_iterator_type> &&r, const index_type start = 0)
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{
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return enumerated_range<range_iterator_type, index_type>(r, start);
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}
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