1 /* 2 Red Black Trees 3 (C) 1999 Andrea Arcangeli <[email protected]> 4 (C) 2002 David Woodhouse <[email protected]> 5 (C) 2012 Michel Lespinasse <[email protected]> 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 21 tools/linux/include/linux/rbtree_augmented.h 22 23 Copied from: 24 linux/include/linux/rbtree_augmented.h 25 */ 26 27 #ifndef _TOOLS_LINUX_RBTREE_AUGMENTED_H 28 #define _TOOLS_LINUX_RBTREE_AUGMENTED_H 29 30 #include <linux/compiler.h> 31 #include <linux/rbtree.h> 32 33 /* 34 * Please note - only struct rb_augment_callbacks and the prototypes for 35 * rb_insert_augmented() and rb_erase_augmented() are intended to be public. 36 * The rest are implementation details you are not expected to depend on. 37 * 38 * See Documentation/rbtree.txt for documentation and samples. 39 */ 40 41 struct rb_augment_callbacks { 42 void (*propagate)(struct rb_node *node, struct rb_node *stop); 43 void (*copy)(struct rb_node *old, struct rb_node *new); 44 void (*rotate)(struct rb_node *old, struct rb_node *new); 45 }; 46 47 extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, 48 void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); 49 /* 50 * Fixup the rbtree and update the augmented information when rebalancing. 51 * 52 * On insertion, the user must update the augmented information on the path 53 * leading to the inserted node, then call rb_link_node() as usual and 54 * rb_augment_inserted() instead of the usual rb_insert_color() call. 55 * If rb_augment_inserted() rebalances the rbtree, it will callback into 56 * a user provided function to update the augmented information on the 57 * affected subtrees. 58 */ 59 static inline void 60 rb_insert_augmented(struct rb_node *node, struct rb_root *root, 61 const struct rb_augment_callbacks *augment) 62 { 63 __rb_insert_augmented(node, root, augment->rotate); 64 } 65 66 #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \ 67 rbtype, rbaugmented, rbcompute) \ 68 static inline void \ 69 rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \ 70 { \ 71 while (rb != stop) { \ 72 rbstruct *node = rb_entry(rb, rbstruct, rbfield); \ 73 rbtype augmented = rbcompute(node); \ 74 if (node->rbaugmented == augmented) \ 75 break; \ 76 node->rbaugmented = augmented; \ 77 rb = rb_parent(&node->rbfield); \ 78 } \ 79 } \ 80 static inline void \ 81 rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ 82 { \ 83 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ 84 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ 85 new->rbaugmented = old->rbaugmented; \ 86 } \ 87 static void \ 88 rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ 89 { \ 90 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ 91 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ 92 new->rbaugmented = old->rbaugmented; \ 93 old->rbaugmented = rbcompute(old); \ 94 } \ 95 rbstatic const struct rb_augment_callbacks rbname = { \ 96 rbname ## _propagate, rbname ## _copy, rbname ## _rotate \ 97 }; 98 99 100 #define RB_RED 0 101 #define RB_BLACK 1 102 103 #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) 104 105 #define __rb_color(pc) ((pc) & 1) 106 #define __rb_is_black(pc) __rb_color(pc) 107 #define __rb_is_red(pc) (!__rb_color(pc)) 108 #define rb_color(rb) __rb_color((rb)->__rb_parent_color) 109 #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) 110 #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) 111 112 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) 113 { 114 rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; 115 } 116 117 static inline void rb_set_parent_color(struct rb_node *rb, 118 struct rb_node *p, int color) 119 { 120 rb->__rb_parent_color = (unsigned long)p | color; 121 } 122 123 static inline void 124 __rb_change_child(struct rb_node *old, struct rb_node *new, 125 struct rb_node *parent, struct rb_root *root) 126 { 127 if (parent) { 128 if (parent->rb_left == old) 129 parent->rb_left = new; 130 else 131 parent->rb_right = new; 132 } else 133 root->rb_node = new; 134 } 135 136 extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, 137 void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); 138 139 static __always_inline struct rb_node * 140 __rb_erase_augmented(struct rb_node *node, struct rb_root *root, 141 const struct rb_augment_callbacks *augment) 142 { 143 struct rb_node *child = node->rb_right, *tmp = node->rb_left; 144 struct rb_node *parent, *rebalance; 145 unsigned long pc; 146 147 if (!tmp) { 148 /* 149 * Case 1: node to erase has no more than 1 child (easy!) 150 * 151 * Note that if there is one child it must be red due to 5) 152 * and node must be black due to 4). We adjust colors locally 153 * so as to bypass __rb_erase_color() later on. 154 */ 155 pc = node->__rb_parent_color; 156 parent = __rb_parent(pc); 157 __rb_change_child(node, child, parent, root); 158 if (child) { 159 child->__rb_parent_color = pc; 160 rebalance = NULL; 161 } else 162 rebalance = __rb_is_black(pc) ? parent : NULL; 163 tmp = parent; 164 } else if (!child) { 165 /* Still case 1, but this time the child is node->rb_left */ 166 tmp->__rb_parent_color = pc = node->__rb_parent_color; 167 parent = __rb_parent(pc); 168 __rb_change_child(node, tmp, parent, root); 169 rebalance = NULL; 170 tmp = parent; 171 } else { 172 struct rb_node *successor = child, *child2; 173 tmp = child->rb_left; 174 if (!tmp) { 175 /* 176 * Case 2: node's successor is its right child 177 * 178 * (n) (s) 179 * / \ / \ 180 * (x) (s) -> (x) (c) 181 * \ 182 * (c) 183 */ 184 parent = successor; 185 child2 = successor->rb_right; 186 augment->copy(node, successor); 187 } else { 188 /* 189 * Case 3: node's successor is leftmost under 190 * node's right child subtree 191 * 192 * (n) (s) 193 * / \ / \ 194 * (x) (y) -> (x) (y) 195 * / / 196 * (p) (p) 197 * / / 198 * (s) (c) 199 * \ 200 * (c) 201 */ 202 do { 203 parent = successor; 204 successor = tmp; 205 tmp = tmp->rb_left; 206 } while (tmp); 207 parent->rb_left = child2 = successor->rb_right; 208 successor->rb_right = child; 209 rb_set_parent(child, successor); 210 augment->copy(node, successor); 211 augment->propagate(parent, successor); 212 } 213 214 successor->rb_left = tmp = node->rb_left; 215 rb_set_parent(tmp, successor); 216 217 pc = node->__rb_parent_color; 218 tmp = __rb_parent(pc); 219 __rb_change_child(node, successor, tmp, root); 220 if (child2) { 221 successor->__rb_parent_color = pc; 222 rb_set_parent_color(child2, parent, RB_BLACK); 223 rebalance = NULL; 224 } else { 225 unsigned long pc2 = successor->__rb_parent_color; 226 successor->__rb_parent_color = pc; 227 rebalance = __rb_is_black(pc2) ? parent : NULL; 228 } 229 tmp = successor; 230 } 231 232 augment->propagate(tmp, NULL); 233 return rebalance; 234 } 235 236 static __always_inline void 237 rb_erase_augmented(struct rb_node *node, struct rb_root *root, 238 const struct rb_augment_callbacks *augment) 239 { 240 struct rb_node *rebalance = __rb_erase_augmented(node, root, augment); 241 if (rebalance) 242 __rb_erase_color(rebalance, root, augment->rotate); 243 } 244 245 #endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */ 246