| 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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