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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