[834] | 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 | class bfs_iterator : public virtual iterator |
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| 32 | { |
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| 33 | friend class tree; |
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| 34 | |
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| 35 | private: |
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| 36 | |
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| 37 | std::list<tree_node<N>*> queue; |
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| 38 | |
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| 39 | typedef bool (*PruningPredicate)(const iterator& iter); |
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| 40 | PruningPredicate prune_pred; |
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| 41 | |
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| 42 | explicit bfs_iterator(tree_node<N>* current) : iterator(current), prune_pred(NULL) { } |
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| 43 | |
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| 44 | public: |
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| 45 | |
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| 46 | bfs_iterator(void) : prune_pred(NULL) { } |
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| 47 | bfs_iterator(const iterator& iter) : iterator(iter), prune_pred(NULL) { } |
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| 48 | |
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| 49 | bfs_iterator endBfs(void) { return bfs_iterator(NULL); } |
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| 50 | |
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| 51 | bfs_iterator& operator ++ (void) |
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| 52 | { |
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| 53 | /* this line necessary for g++ 3.4 onward */ |
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| 54 | tree_node<N>*& current = this->current; |
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| 55 | |
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| 56 | assert(current != NULL); |
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| 57 | |
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| 58 | if (prune_pred == NULL || !prune_pred(*this)) |
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| 59 | { |
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| 60 | for (tree_node<N>* p = current->first_child; |
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| 61 | p != NULL; p = p->next_sibling) |
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| 62 | { |
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| 63 | queue.push_front(p); |
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| 64 | } |
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| 65 | } |
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| 66 | |
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| 67 | if (queue.empty()) |
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| 68 | { |
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| 69 | current = NULL; |
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| 70 | } |
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| 71 | else |
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| 72 | { |
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| 73 | current = queue.back(); |
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| 74 | queue.pop_back(); |
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| 75 | } |
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| 76 | |
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| 77 | return *this; |
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| 78 | } |
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| 79 | |
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| 80 | /** When the iterator points to a node, and the pruning predicate |
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| 81 | * returns true, the children of the node are not added to the BFS |
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| 82 | * queue. True means prune everything beneath the node passed |
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| 83 | * to the predicate. A NULL predicate disables pruning. */ |
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| 84 | void pruneOn(PruningPredicate prune_pred) |
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| 85 | { |
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| 86 | this->prune_pred = prune_pred; |
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| 87 | } |
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| 88 | }; |
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| 89 | |
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