82 lines
2.8 KiB
C++
82 lines
2.8 KiB
C++
#ifndef __CXXMPH_HOLLOW_ITERATOR_H__
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#define __CXXMPH_HOLLOW_ITERATOR_H__
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#include <vector>
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namespace cxxmph {
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using std::vector;
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template <typename container_type>
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struct is_empty {
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public:
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is_empty() : c_(NULL), p_(NULL) {};
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is_empty(const container_type* c, const vector<bool>* p) : c_(c), p_(p) {};
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bool operator()(typename container_type::const_iterator it) const {
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if (it == c_->end()) return false;
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return !(*p_)[it - c_->begin()];
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}
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private:
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const container_type* c_;
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const vector<bool>* p_;
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};
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template <typename iterator, typename is_empty>
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struct hollow_iterator_base
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: public std::iterator<std::forward_iterator_tag,
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typename iterator::value_type> {
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public:
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typedef hollow_iterator_base<iterator, is_empty> self_type;
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typedef self_type& self_reference;
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typedef typename iterator::reference reference;
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typedef typename iterator::pointer pointer;
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inline hollow_iterator_base() : it_(), empty_() { }
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inline hollow_iterator_base(iterator it, is_empty empty, bool solid) : it_(it), empty_(empty) {
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if (!solid) advance();
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}
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// Same as above, assumes solid==true.
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inline hollow_iterator_base(iterator it, is_empty empty) : it_(it), empty_(empty) {}
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inline hollow_iterator_base(const self_type& rhs) { it_ = rhs.it_; empty_ = rhs.empty_; }
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template <typename const_iterator>
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hollow_iterator_base(const hollow_iterator_base<const_iterator, is_empty>& rhs) { it_ = rhs.it_; empty_ = rhs.empty_; }
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reference operator*() { return *it_; }
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pointer operator->() { return &(*it_); }
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self_reference operator++() { ++it_; advance(); return *this; }
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// self_type operator++() { auto tmp(*this); ++tmp; return tmp; }
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template <typename const_iterator>
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bool operator==(const hollow_iterator_base<const_iterator, is_empty>& rhs) { return rhs.it_ == it_; }
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template <typename const_iterator>
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bool operator!=(const hollow_iterator_base<const_iterator, is_empty>& rhs) { return rhs.it_ != it_; }
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// should be friend
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iterator it_;
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is_empty empty_;
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private:
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void advance() {
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while (empty_(it_)) ++it_;
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}
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};
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template <typename container_type, typename iterator>
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inline auto make_solid(
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container_type* v, const vector<bool>* p, iterator it) ->
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hollow_iterator_base<iterator, is_empty<const container_type>> {
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return hollow_iterator_base<iterator, is_empty<const container_type>>(
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it, is_empty<const container_type>(v, p));
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}
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template <typename container_type, typename iterator>
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inline auto make_hollow(
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container_type* v, const vector<bool>* p, iterator it) ->
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hollow_iterator_base<iterator, is_empty<const container_type>> {
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return hollow_iterator_base<iterator, is_empty<const container_type>>(
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it, is_empty<const container_type>(v, p), false);
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}
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} // namespace cxxmph
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#endif // __CXXMPH_HOLLOW_ITERATOR_H__
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