4.115
Last change
on this file since 2d7ae960 was
f53aa8d,
checked in by Gedare Bloom <gedare@…>, on 05/03/12 at 16:43:29
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rbtree: API changes. Remove rbtree control node from RBTree_Next.
The implementation of RBTree_Next was using an awkward construction to detect
and avoid accessing the false root of the red-black tree. To deal with the
false root, RBTree_Next was comparing node parents with the control node.
Instead the false root can be detected by checking if the grandparent of a
node exists; the grandparent of the tree's true root is NULL by definition
so the root of the tree is found while walking up the tree by checking for
the non-existence of a grandparent.
This change propagates into the predecessor/successor and iterate functions.
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-
Property mode set to
100644
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File size:
1.5 KB
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1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup ScoreRBTree |
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5 | * |
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6 | * @brief _RBTree_Next_unprotected() and _RBTree_Next() implementation. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (c) 2012 embedded brains GmbH. All rights reserved. |
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11 | * |
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12 | * embedded brains GmbH |
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13 | * Obere Lagerstr. 30 |
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14 | * 82178 Puchheim |
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15 | * Germany |
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16 | * <rtems@embedded-brains.de> |
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17 | * |
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18 | * The license and distribution terms for this file may be |
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19 | * found in the file LICENSE in this distribution or at |
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20 | * http://www.rtems.com/license/LICENSE. |
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21 | */ |
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22 | |
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23 | #if HAVE_CONFIG_H |
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24 | #include "config.h" |
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25 | #endif |
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26 | |
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27 | #include <rtems/score/rbtree.h> |
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28 | #include <rtems/score/isr.h> |
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29 | |
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30 | RBTree_Node *_RBTree_Next_unprotected( |
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31 | const RBTree_Node *node, |
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32 | RBTree_Direction dir |
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33 | ) |
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34 | { |
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35 | RBTree_Direction opp_dir = _RBTree_Opposite_direction( dir ); |
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36 | RBTree_Node *current = node->child [dir]; |
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37 | RBTree_Node *next = NULL; |
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38 | |
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39 | if ( current != NULL ) { |
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40 | next = current; |
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41 | while ( (current = current->child [opp_dir]) != NULL ) { |
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42 | next = current; |
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43 | } |
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44 | } else { |
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45 | RBTree_Node *parent = node->parent; |
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46 | |
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47 | if ( parent->parent && node == parent->child [opp_dir] ) { |
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48 | next = parent; |
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49 | } else { |
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50 | while ( parent->parent && node == parent->child [dir] ) { |
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51 | node = parent; |
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52 | parent = parent->parent; |
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53 | } |
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54 | |
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55 | if ( parent->parent ) { |
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56 | next = parent; |
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57 | } |
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58 | } |
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59 | } |
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60 | |
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61 | return next; |
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62 | } |
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63 | |
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64 | RBTree_Node *_RBTree_Next( |
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65 | const RBTree_Node *node, |
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66 | RBTree_Direction dir |
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67 | ) |
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68 | { |
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69 | RBTree_Node *next; |
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70 | ISR_Level level; |
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71 | |
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72 | _ISR_Disable( level ); |
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73 | next = _RBTree_Next_unprotected( node, dir ); |
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74 | _ISR_Enable( level ); |
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75 | |
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76 | return next; |
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77 | } |
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