| 1 | /* |
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| 2 | Copyright (c) 2003-2006, Troy Aaron Johnson |
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| 3 | All rights reserved. |
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| 4 | |
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| 5 | Redistribution and use in source and binary forms, with or without |
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| 6 | modification, are permitted provided that the following conditions |
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| 7 | are met: |
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| 8 | |
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| 9 | * Redistributions of source code must retain the above copyright |
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| 10 | notice, this list of conditions and the following disclaimer. |
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| 11 | * Redistributions in binary form must reproduce the above copyright |
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| 12 | notice, this list of conditions and the following disclaimer in the |
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| 13 | documentation and/or other materials provided with the distribution. |
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| 14 | * Neither the name of Troy Aaron Johnson nor the names of any |
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| 15 | contributors may be used to endorse or promote products derived from |
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| 16 | this software without specific prior written permission. |
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| 17 | |
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| 18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| 19 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 20 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 21 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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| 22 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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| 23 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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| 24 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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| 25 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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| 26 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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| 27 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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| 28 | POSSIBILITY OF SUCH DAMAGE. |
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| 29 | */ |
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| 30 | |
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| 31 | /** The base template for all iterators. |
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| 32 | */ |
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| 33 | template <class T, class R, class P> |
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| 34 | class tree_iterator |
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| 35 | { |
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| 36 | friend class tree; |
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| 37 | |
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| 38 | protected: |
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| 39 | |
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| 40 | /* The node pointed to by this iterator. */ |
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| 41 | tree_node<N>* current; |
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| 42 | |
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| 43 | /* This is the depth of an iterator relative to its starting position. |
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| 44 | The starting depth is 0, the depth of the parent is -1, the depth |
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| 45 | of any child is 1, the depth of any grandchild is 2, etc. */ |
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| 46 | long iter_depth; |
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| 47 | |
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| 48 | /** Allows derived classes to create an iterator |
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| 49 | * from a pointer to a node. This constructor |
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| 50 | * is not explicit because the tree_iterator class |
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| 51 | * contains the == and != operators, which are used |
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| 52 | * throughout the template to compare iterators |
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| 53 | * to NULL. The tree_iterator class is not visible |
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| 54 | * to the user, so this implicit constructor is |
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| 55 | * entirely for my convenience when coding the template. |
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| 56 | * |
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| 57 | * @param current Position for the new iterator |
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| 58 | */ |
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| 59 | tree_iterator(tree_node<N>* current) : current(current), iter_depth(0L) { } |
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| 60 | |
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| 61 | /** Destroys the node pointed to by this iterator. |
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| 62 | */ |
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| 63 | void destroy(void) |
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| 64 | { |
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| 65 | delete current; |
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| 66 | current = NULL; |
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| 67 | iter_depth = 0L; |
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| 68 | } |
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| 69 | |
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| 70 | /* increment and decrement methods used by both the iterator |
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| 71 | and the const_iterator versions of various iterators */ |
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| 72 | |
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| 73 | static inline void post_inc(tree_node<N>*& current, long& depth); |
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| 74 | static inline void post_dec(tree_node<N>*& current, long& depth); |
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| 75 | |
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| 76 | static inline void pre_inc(tree_node<N>*& current, long& depth); |
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| 77 | static inline void pre_dec(tree_node<N>*& current, long& depth); |
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| 78 | |
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| 79 | static inline void sib_inc(tree_node<N>*& current); |
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| 80 | static inline void sib_dec(tree_node<N>*& current); |
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| 81 | |
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| 82 | public: |
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| 83 | |
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| 84 | /* The following typedefs are required for compatibility |
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| 85 | * with standard containers. */ |
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| 86 | |
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| 87 | typedef std::bidirectional_iterator_tag iterator_category; |
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| 88 | typedef T value_type; |
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| 89 | typedef R reference; |
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| 90 | typedef P pointer; |
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| 91 | typedef size_t size_type; |
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| 92 | typedef ptrdiff_t difference_type; |
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| 93 | |
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| 94 | tree_iterator(void) : current(NULL), iter_depth(0L) { } |
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| 95 | |
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| 96 | tree_iterator(const tree_iterator& iter) |
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| 97 | : current(iter.current), iter_depth(iter.iter_depth) { } |
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| 98 | |
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| 99 | /* note that depth is not relevant when comparing iterators */ |
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| 100 | |
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| 101 | bool operator == (const tree_iterator& iter) const |
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| 102 | { return this->current == iter.current; } |
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| 103 | |
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| 104 | bool operator != (const tree_iterator& iter) const |
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| 105 | { return this->current != iter.current; } |
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| 106 | |
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| 107 | long depth(void) const { return iter_depth; } |
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| 108 | |
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| 109 | bool leaf(void) const { return this->first_child == NULL; } |
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| 110 | }; |
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