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| Rev | Author | Line No. | Line |
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| 5056 | serge | 1 | /* |
| 2 | Interval Trees |
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| 3 | (C) 2012 Michel Lespinasse |
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| 4 | |||
| 5 | This program is free software; you can redistribute it and/or modify |
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| 6 | it under the terms of the GNU General Public License as published by |
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| 7 | the Free Software Foundation; either version 2 of the License, or |
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| 8 | (at your option) any later version. |
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| 9 | |||
| 10 | This program is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 13 | GNU General Public License for more details. |
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| 14 | |||
| 15 | You should have received a copy of the GNU General Public License |
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| 16 | along with this program; if not, write to the Free Software |
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| 17 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 18 | |||
| 19 | include/linux/interval_tree_generic.h |
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| 20 | */ |
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| 21 | |||
| 22 | #include |
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| 23 | |||
| 24 | /* |
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| 25 | * Template for implementing interval trees |
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| 26 | * |
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| 27 | * ITSTRUCT: struct type of the interval tree nodes |
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| 28 | * ITRB: name of struct rb_node field within ITSTRUCT |
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| 29 | * ITTYPE: type of the interval endpoints |
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| 30 | * ITSUBTREE: name of ITTYPE field within ITSTRUCT holding last-in-subtree |
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| 31 | * ITSTART(n): start endpoint of ITSTRUCT node n |
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| 32 | * ITLAST(n): last endpoint of ITSTRUCT node n |
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| 33 | * ITSTATIC: 'static' or empty |
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| 34 | * ITPREFIX: prefix to use for the inline tree definitions |
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| 35 | * |
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| 36 | * Note - before using this, please consider if non-generic version |
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| 37 | * (interval_tree.h) would work for you... |
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| 38 | */ |
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| 39 | |||
| 40 | #define INTERVAL_TREE_DEFINE(ITSTRUCT, ITRB, ITTYPE, ITSUBTREE, \ |
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| 41 | ITSTART, ITLAST, ITSTATIC, ITPREFIX) \ |
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| 42 | \ |
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| 43 | /* Callbacks for augmented rbtree insert and remove */ \ |
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| 44 | \ |
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| 45 | static inline ITTYPE ITPREFIX ## _compute_subtree_last(ITSTRUCT *node) \ |
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| 46 | { \ |
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| 47 | ITTYPE max = ITLAST(node), subtree_last; \ |
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| 48 | if (node->ITRB.rb_left) { \ |
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| 49 | subtree_last = rb_entry(node->ITRB.rb_left, \ |
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| 50 | ITSTRUCT, ITRB)->ITSUBTREE; \ |
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| 51 | if (max < subtree_last) \ |
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| 52 | max = subtree_last; \ |
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| 53 | } \ |
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| 54 | if (node->ITRB.rb_right) { \ |
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| 55 | subtree_last = rb_entry(node->ITRB.rb_right, \ |
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| 56 | ITSTRUCT, ITRB)->ITSUBTREE; \ |
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| 57 | if (max < subtree_last) \ |
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| 58 | max = subtree_last; \ |
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| 59 | } \ |
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| 60 | return max; \ |
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| 61 | } \ |
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| 62 | \ |
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| 63 | RB_DECLARE_CALLBACKS(static, ITPREFIX ## _augment, ITSTRUCT, ITRB, \ |
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| 64 | ITTYPE, ITSUBTREE, ITPREFIX ## _compute_subtree_last) \ |
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| 65 | \ |
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| 66 | /* Insert / remove interval nodes from the tree */ \ |
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| 67 | \ |
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| 68 | ITSTATIC void ITPREFIX ## _insert(ITSTRUCT *node, struct rb_root *root) \ |
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| 69 | { \ |
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| 70 | struct rb_node **link = &root->rb_node, *rb_parent = NULL; \ |
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| 71 | ITTYPE start = ITSTART(node), last = ITLAST(node); \ |
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| 72 | ITSTRUCT *parent; \ |
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| 73 | \ |
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| 74 | while (*link) { \ |
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| 75 | rb_parent = *link; \ |
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| 76 | parent = rb_entry(rb_parent, ITSTRUCT, ITRB); \ |
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| 77 | if (parent->ITSUBTREE < last) \ |
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| 78 | parent->ITSUBTREE = last; \ |
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| 79 | if (start < ITSTART(parent)) \ |
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| 80 | link = &parent->ITRB.rb_left; \ |
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| 81 | else \ |
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| 82 | link = &parent->ITRB.rb_right; \ |
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| 83 | } \ |
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| 84 | \ |
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| 85 | node->ITSUBTREE = last; \ |
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| 86 | rb_link_node(&node->ITRB, rb_parent, link); \ |
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| 87 | rb_insert_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \ |
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| 88 | } \ |
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| 89 | \ |
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| 90 | ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, struct rb_root *root) \ |
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| 91 | { \ |
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| 92 | rb_erase_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \ |
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| 93 | } \ |
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| 94 | \ |
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| 95 | /* \ |
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| 96 | * Iterate over intervals intersecting [start;last] \ |
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| 97 | * \ |
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| 98 | * Note that a node's interval intersects [start;last] iff: \ |
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| 99 | * Cond1: ITSTART(node) <= last \ |
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| 100 | * and \ |
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| 101 | * Cond2: start <= ITLAST(node) \ |
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| 102 | */ \ |
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| 103 | \ |
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| 104 | static ITSTRUCT * \ |
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| 105 | ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \ |
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| 106 | { \ |
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| 107 | while (true) { \ |
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| 108 | /* \ |
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| 109 | * Loop invariant: start <= node->ITSUBTREE \ |
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| 110 | * (Cond2 is satisfied by one of the subtree nodes) \ |
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| 111 | */ \ |
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| 112 | if (node->ITRB.rb_left) { \ |
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| 113 | ITSTRUCT *left = rb_entry(node->ITRB.rb_left, \ |
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| 114 | ITSTRUCT, ITRB); \ |
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| 115 | if (start <= left->ITSUBTREE) { \ |
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| 116 | /* \ |
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| 117 | * Some nodes in left subtree satisfy Cond2. \ |
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| 118 | * Iterate to find the leftmost such node N. \ |
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| 119 | * If it also satisfies Cond1, that's the \ |
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| 120 | * match we are looking for. Otherwise, there \ |
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| 121 | * is no matching interval as nodes to the \ |
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| 122 | * right of N can't satisfy Cond1 either. \ |
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| 123 | */ \ |
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| 124 | node = left; \ |
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| 125 | continue; \ |
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| 126 | } \ |
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| 127 | } \ |
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| 128 | if (ITSTART(node) <= last) { /* Cond1 */ \ |
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| 129 | if (start <= ITLAST(node)) /* Cond2 */ \ |
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| 130 | return node; /* node is leftmost match */ \ |
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| 131 | if (node->ITRB.rb_right) { \ |
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| 132 | node = rb_entry(node->ITRB.rb_right, \ |
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| 133 | ITSTRUCT, ITRB); \ |
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| 134 | if (start <= node->ITSUBTREE) \ |
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| 135 | continue; \ |
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| 136 | } \ |
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| 137 | } \ |
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| 138 | return NULL; /* No match */ \ |
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| 139 | } \ |
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| 140 | } \ |
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| 141 | \ |
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| 142 | ITSTATIC ITSTRUCT * \ |
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| 143 | ITPREFIX ## _iter_first(struct rb_root *root, ITTYPE start, ITTYPE last) \ |
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| 144 | { \ |
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| 145 | ITSTRUCT *node; \ |
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| 146 | \ |
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| 147 | if (!root->rb_node) \ |
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| 148 | return NULL; \ |
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| 149 | node = rb_entry(root->rb_node, ITSTRUCT, ITRB); \ |
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| 150 | if (node->ITSUBTREE < start) \ |
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| 151 | return NULL; \ |
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| 152 | return ITPREFIX ## _subtree_search(node, start, last); \ |
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| 153 | } \ |
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| 154 | \ |
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| 155 | ITSTATIC ITSTRUCT * \ |
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| 156 | ITPREFIX ## _iter_next(ITSTRUCT *node, ITTYPE start, ITTYPE last) \ |
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| 157 | { \ |
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| 158 | struct rb_node *rb = node->ITRB.rb_right, *prev; \ |
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| 159 | \ |
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| 160 | while (true) { \ |
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| 161 | /* \ |
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| 162 | * Loop invariants: \ |
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| 163 | * Cond1: ITSTART(node) <= last \ |
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| 164 | * rb == node->ITRB.rb_right \ |
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| 165 | * \ |
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| 166 | * First, search right subtree if suitable \ |
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| 167 | */ \ |
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| 168 | if (rb) { \ |
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| 169 | ITSTRUCT *right = rb_entry(rb, ITSTRUCT, ITRB); \ |
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| 170 | if (start <= right->ITSUBTREE) \ |
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| 171 | return ITPREFIX ## _subtree_search(right, \ |
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| 172 | start, last); \ |
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| 173 | } \ |
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| 174 | \ |
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| 175 | /* Move up the tree until we come from a node's left child */ \ |
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| 176 | do { \ |
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| 177 | rb = rb_parent(&node->ITRB); \ |
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| 178 | if (!rb) \ |
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| 179 | return NULL; \ |
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| 180 | prev = &node->ITRB; \ |
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| 181 | node = rb_entry(rb, ITSTRUCT, ITRB); \ |
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| 182 | rb = node->ITRB.rb_right; \ |
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| 183 | } while (prev == rb); \ |
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| 184 | \ |
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| 185 | /* Check if the node intersects [start;last] */ \ |
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| 186 | if (last < ITSTART(node)) /* !Cond1 */ \ |
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| 187 | return NULL; \ |
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| 188 | else if (start <= ITLAST(node)) /* Cond2 */ \ |
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| 189 | return node; \ |
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| 190 | } \ |
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| 191 | } |