[774] | 1 | //
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| 2 | // Copyright (C) 2004 Tanguy Fautré.
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| 3 | // For conditions of distribution and use,
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| 4 | // see copyright notice in tri_stripper.h
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| 5 | //
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| 6 | //////////////////////////////////////////////////////////////////////
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| 7 | // SVN: $Id: heap_array.h 86 2005-06-08 17:47:27Z gpsnoopy $
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| 8 | //////////////////////////////////////////////////////////////////////
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| 9 |
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| 10 | #ifndef TRI_STRIPPER_HEADER_GUARD_HEAP_ARRAY_H
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| 11 | #define TRI_STRIPPER_HEADER_GUARD_HEAP_ARRAY_H
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| 12 |
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| 13 | #include <vector>
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| 14 |
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| 15 |
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| 16 |
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| 17 |
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| 18 | namespace triangle_stripper {
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| 19 |
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| 20 | namespace detail {
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| 21 |
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| 22 |
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| 23 |
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| 24 |
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| 25 | // mutable heap
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| 26 | // can be interfaced pretty muck like an array
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| 27 | template <class T, class CmpT = std::less<T> >
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| 28 | class heap_array
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| 29 | {
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| 30 | public:
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| 31 |
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| 32 | // Pre = PreCondition, Post = PostCondition
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| 33 |
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| 34 | heap_array() : m_Locked(false) { } // Post: ((size() == 0) && ! locked())
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| 35 |
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| 36 | void clear(); // Post: ((size() == 0) && ! locked())
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| 37 |
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| 38 | void reserve(size_t Size);
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| 39 | size_t size() const;
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| 40 |
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| 41 | bool empty() const;
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| 42 | bool locked() const;
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| 43 | bool removed(size_t i) const; // Pre: (valid(i))
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| 44 | bool valid(size_t i) const;
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| 45 |
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| 46 | size_t position(size_t i) const; // Pre: (valid(i))
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| 47 |
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| 48 | const T & top() const; // Pre: (! empty())
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| 49 | const T & peek(size_t i) const; // Pre: (! removed(i))
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| 50 | const T & operator [] (size_t i) const; // Pre: (! removed(i))
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| 51 |
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| 52 | void lock(); // Pre: (! locked()) Post: (locked())
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| 53 | size_t push(const T & Elem); // Pre: (! locked())
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| 54 |
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| 55 | void pop(); // Pre: (locked() && ! empty())
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| 56 | void erase(size_t i); // Pre: (locked() && ! removed(i))
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| 57 | void update(size_t i, const T & Elem); // Pre: (locked() && ! removed(i))
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| 58 |
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| 59 | protected:
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| 60 |
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| 61 | heap_array(const heap_array &);
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| 62 | heap_array & operator = (const heap_array &);
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| 63 |
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| 64 | class linker
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| 65 | {
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| 66 | public:
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| 67 | linker(const T & Elem, size_t i)
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| 68 | : m_Elem(Elem), m_Index(i) { }
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| 69 |
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| 70 | T m_Elem;
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| 71 | size_t m_Index;
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| 72 | };
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| 73 |
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| 74 | typedef std::vector<linker> linked_heap;
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| 75 | typedef std::vector<size_t> finder;
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| 76 |
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| 77 | void Adjust(size_t i);
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| 78 | void Swap(size_t a, size_t b);
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| 79 | bool Less(const linker & a, const linker & b) const;
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| 80 |
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| 81 | linked_heap m_Heap;
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| 82 | finder m_Finder;
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| 83 | CmpT m_Compare;
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| 84 | bool m_Locked;
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| 85 | };
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| 86 |
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| 87 |
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| 88 |
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| 89 |
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| 90 |
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| 91 | //////////////////////////////////////////////////////////////////////////
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| 92 | // heap_indexed inline functions
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| 93 | //////////////////////////////////////////////////////////////////////////
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| 94 |
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| 95 | template <class T, class CmpT>
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| 96 | inline void heap_array<T, CmpT>::clear()
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| 97 | {
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| 98 | m_Heap.clear();
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| 99 | m_Finder.clear();
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| 100 | m_Locked = false;
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| 101 | }
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| 102 |
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| 103 |
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| 104 | template <class T, class CmpT>
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| 105 | inline bool heap_array<T, CmpT>::empty() const
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| 106 | {
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| 107 | return m_Heap.empty();
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| 108 | }
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| 109 |
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| 110 |
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| 111 | template <class T, class CmpT>
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| 112 | inline bool heap_array<T, CmpT>::locked() const
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| 113 | {
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| 114 | return m_Locked;
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| 115 | }
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| 116 |
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| 117 |
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| 118 | template <class T, class CmpT>
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| 119 | inline void heap_array<T, CmpT>::reserve(const size_t Size)
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| 120 | {
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| 121 | m_Heap.reserve(Size);
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| 122 | m_Finder.reserve(Size);
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| 123 | }
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| 124 |
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| 125 |
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| 126 | template <class T, class CmpT>
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| 127 | inline size_t heap_array<T, CmpT>::size() const
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| 128 | {
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| 129 | return m_Heap.size();
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| 130 | }
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| 131 |
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| 132 |
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| 133 | template <class T, class CmpT>
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| 134 | inline const T & heap_array<T, CmpT>::top() const
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| 135 | {
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| 136 | assert(! empty());
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| 137 |
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| 138 | return m_Heap.front().m_Elem;
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| 139 | }
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| 140 |
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| 141 |
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| 142 | template <class T, class CmpT>
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| 143 | inline const T & heap_array<T, CmpT>::peek(const size_t i) const
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| 144 | {
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| 145 | assert(! removed(i));
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| 146 |
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| 147 | return (m_Heap[m_Finder[i]].m_Elem);
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| 148 | }
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| 149 |
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| 150 |
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| 151 | template <class T, class CmpT>
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| 152 | inline const T & heap_array<T, CmpT>::operator [] (const size_t i) const
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| 153 | {
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| 154 | return peek(i);
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| 155 | }
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| 156 |
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| 157 |
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| 158 | template <class T, class CmpT>
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| 159 | inline void heap_array<T, CmpT>::pop()
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| 160 | {
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| 161 | assert(locked());
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| 162 | assert(! empty());
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| 163 |
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| 164 | Swap(0, size() - 1);
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| 165 | m_Heap.pop_back();
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| 166 |
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| 167 | if (! empty())
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| 168 | Adjust(0);
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| 169 | }
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| 170 |
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| 171 |
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| 172 | template <class T, class CmpT>
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| 173 | inline void heap_array<T, CmpT>::lock()
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| 174 | {
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| 175 | assert(! locked());
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| 176 |
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| 177 | m_Locked =true;
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| 178 | }
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| 179 |
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| 180 |
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| 181 | template <class T, class CmpT>
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| 182 | inline size_t heap_array<T, CmpT>::push(const T & Elem)
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| 183 | {
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| 184 | assert(! locked());
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| 185 |
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| 186 | const size_t Id = size();
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| 187 | m_Finder.push_back(Id);
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| 188 | m_Heap.push_back(linker(Elem, Id));
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| 189 | Adjust(Id);
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| 190 |
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| 191 | return Id;
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| 192 | }
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| 193 |
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| 194 |
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| 195 | template <class T, class CmpT>
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| 196 | inline void heap_array<T, CmpT>::erase(const size_t i)
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| 197 | {
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| 198 | assert(locked());
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| 199 | assert(! removed(i));
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| 200 |
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| 201 | const size_t j = m_Finder[i];
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| 202 | Swap(j, size() - 1);
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| 203 | m_Heap.pop_back();
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| 204 |
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| 205 | if (j != size())
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| 206 | Adjust(j);
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| 207 | }
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| 208 |
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| 209 |
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| 210 | template <class T, class CmpT>
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| 211 | inline bool heap_array<T, CmpT>::removed(const size_t i) const
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| 212 | {
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| 213 | assert(valid(i));
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| 214 |
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| 215 | return (m_Finder[i] >= m_Heap.size());
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| 216 | }
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| 217 |
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| 218 |
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| 219 | template <class T, class CmpT>
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| 220 | inline bool heap_array<T, CmpT>::valid(const size_t i) const
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| 221 | {
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| 222 | return (i < m_Finder.size());
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| 223 | }
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| 224 |
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| 225 |
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| 226 | template <class T, class CmpT>
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| 227 | inline size_t heap_array<T, CmpT>::position(const size_t i) const
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| 228 | {
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| 229 | assert(valid(i));
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| 230 |
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| 231 | return (m_Heap[i].m_Index);
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| 232 | }
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| 233 |
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| 234 |
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| 235 | template <class T, class CmpT>
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| 236 | inline void heap_array<T, CmpT>::update(const size_t i, const T & Elem)
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| 237 | {
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| 238 | assert(locked());
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| 239 | assert(! removed(i));
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| 240 |
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| 241 | const size_t j = m_Finder[i];
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| 242 | m_Heap[j].m_Elem = Elem;
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| 243 | Adjust(j);
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| 244 | }
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| 245 |
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| 246 |
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| 247 | template <class T, class CmpT>
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| 248 | inline void heap_array<T, CmpT>::Adjust(size_t i)
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| 249 | {
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| 250 | assert(i < m_Heap.size());
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| 251 |
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| 252 | size_t j;
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| 253 |
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| 254 | // Check the upper part of the heap
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| 255 | for (j = i; (j > 0) && (Less(m_Heap[(j - 1) / 2], m_Heap[j])); j = ((j - 1) / 2))
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| 256 | Swap(j, (j - 1) / 2);
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| 257 |
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| 258 | // Check the lower part of the heap
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| 259 | for (i = j; (j = 2 * i + 1) < size(); i = j) {
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| 260 | if ((j + 1 < size()) && (Less(m_Heap[j], m_Heap[j + 1])))
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| 261 | ++j;
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| 262 |
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| 263 | if (Less(m_Heap[j], m_Heap[i]))
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| 264 | return;
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| 265 |
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| 266 | Swap(i, j);
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| 267 | }
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| 268 | }
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| 269 |
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| 270 |
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| 271 | template <class T, class CmpT>
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| 272 | inline void heap_array<T, CmpT>::Swap(const size_t a, const size_t b)
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| 273 | {
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| 274 | std::swap(m_Heap[a], m_Heap[b]);
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| 275 |
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| 276 | m_Finder[(m_Heap[a].m_Index)] = a;
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| 277 | m_Finder[(m_Heap[b].m_Index)] = b;
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| 278 | }
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| 279 |
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| 280 |
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| 281 | template <class T, class CmpT>
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| 282 | inline bool heap_array<T, CmpT>::Less(const linker & a, const linker & b) const
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| 283 | {
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| 284 | return m_Compare(a.m_Elem, b.m_Elem);
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| 285 | }
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| 286 |
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| 287 |
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| 288 |
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| 289 |
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| 290 | } // namespace detail
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| 291 |
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| 292 | } // namespace triangle_stripper
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| 293 |
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| 294 |
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| 295 |
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| 296 |
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| 297 | #endif // TRI_STRIPPER_HEADER_GUARD_HEAP_ARRAY_H
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