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, 48 struct rb_root *root, 49 bool newleft, struct rb_node **leftmost, 50 void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); 51 /* 52 * Fixup the rbtree and update the augmented information when rebalancing. 53 * 54 * On insertion, the user must update the augmented information on the path 55 * leading to the inserted node, then call rb_link_node() as usual and 56 * rb_augment_inserted() instead of the usual rb_insert_color() call. 57 * If rb_augment_inserted() rebalances the rbtree, it will callback into 58 * a user provided function to update the augmented information on the 59 * affected subtrees. 60 */ 61 static inline void 62 rb_insert_augmented(struct rb_node *node, struct rb_root *root, 63 const struct rb_augment_callbacks *augment) 64 { 65 __rb_insert_augmented(node, root, false, NULL, augment->rotate); 66 } 67 68 static inline void 69 rb_insert_augmented_cached(struct rb_node *node, 70 struct rb_root_cached *root, bool newleft, 71 const struct rb_augment_callbacks *augment) 72 { 73 __rb_insert_augmented(node, &root->rb_root, 74 newleft, &root->rb_leftmost, augment->rotate); 75 } 76 77 #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \ 78 rbtype, rbaugmented, rbcompute) \ 79 static inline void \ 80 rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \ 81 { \ 82 while (rb != stop) { \ 83 rbstruct *node = rb_entry(rb, rbstruct, rbfield); \ 84 rbtype augmented = rbcompute(node); \ 85 if (node->rbaugmented == augmented) \ 86 break; \ 87 node->rbaugmented = augmented; \ 88 rb = rb_parent(&node->rbfield); \ 89 } \ 90 } \ 91 static inline void \ 92 rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ 93 { \ 94 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ 95 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ 96 new->rbaugmented = old->rbaugmented; \ 97 } \ 98 static void \ 99 rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ 100 { \ 101 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ 102 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ 103 new->rbaugmented = old->rbaugmented; \ 104 old->rbaugmented = rbcompute(old); \ 105 } \ 106 rbstatic const struct rb_augment_callbacks rbname = { \ 107 .propagate = rbname ## _propagate, \ 108 .copy = rbname ## _copy, \ 109 .rotate = rbname ## _rotate \ 110 }; 111 112 113 #define RB_RED 0 114 #define RB_BLACK 1 115 116 #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) 117 118 #define __rb_color(pc) ((pc) & 1) 119 #define __rb_is_black(pc) __rb_color(pc) 120 #define __rb_is_red(pc) (!__rb_color(pc)) 121 #define rb_color(rb) __rb_color((rb)->__rb_parent_color) 122 #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) 123 #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) 124 125 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) 126 { 127 rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; 128 } 129 130 static inline void rb_set_parent_color(struct rb_node *rb, 131 struct rb_node *p, int color) 132 { 133 rb->__rb_parent_color = (unsigned long)p | color; 134 } 135 136 static inline void 137 __rb_change_child(struct rb_node *old, struct rb_node *new, 138 struct rb_node *parent, struct rb_root *root) 139 { 140 if (parent) { 141 if (parent->rb_left == old) 142 WRITE_ONCE(parent->rb_left, new); 143 else 144 WRITE_ONCE(parent->rb_right, new); 145 } else 146 WRITE_ONCE(root->rb_node, new); 147 } 148 149 extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, 150 void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); 151 152 static __always_inline struct rb_node * 153 __rb_erase_augmented(struct rb_node *node, struct rb_root *root, 154 struct rb_node **leftmost, 155 const struct rb_augment_callbacks *augment) 156 { 157 struct rb_node *child = node->rb_right; 158 struct rb_node *tmp = node->rb_left; 159 struct rb_node *parent, *rebalance; 160 unsigned long pc; 161 162 if (leftmost && node == *leftmost) 163 *leftmost = rb_next(node); 164 165 if (!tmp) { 166 /* 167 * Case 1: node to erase has no more than 1 child (easy!) 168 * 169 * Note that if there is one child it must be red due to 5) 170 * and node must be black due to 4). We adjust colors locally 171 * so as to bypass __rb_erase_color() later on. 172 */ 173 pc = node->__rb_parent_color; 174 parent = __rb_parent(pc); 175 __rb_change_child(node, child, parent, root); 176 if (child) { 177 child->__rb_parent_color = pc; 178 rebalance = NULL; 179 } else 180 rebalance = __rb_is_black(pc) ? parent : NULL; 181 tmp = parent; 182 } else if (!child) { 183 /* Still case 1, but this time the child is node->rb_left */ 184 tmp->__rb_parent_color = pc = node->__rb_parent_color; 185 parent = __rb_parent(pc); 186 __rb_change_child(node, tmp, parent, root); 187 rebalance = NULL; 188 tmp = parent; 189 } else { 190 struct rb_node *successor = child, *child2; 191 192 tmp = child->rb_left; 193 if (!tmp) { 194 /* 195 * Case 2: node's successor is its right child 196 * 197 * (n) (s) 198 * / \ / \ 199 * (x) (s) -> (x) (c) 200 * \ 201 * (c) 202 */ 203 parent = successor; 204 child2 = successor->rb_right; 205 206 augment->copy(node, successor); 207 } else { 208 /* 209 * Case 3: node's successor is leftmost under 210 * node's right child subtree 211 * 212 * (n) (s) 213 * / \ / \ 214 * (x) (y) -> (x) (y) 215 * / / 216 * (p) (p) 217 * / / 218 * (s) (c) 219 * \ 220 * (c) 221 */ 222 do { 223 parent = successor; 224 successor = tmp; 225 tmp = tmp->rb_left; 226 } while (tmp); 227 child2 = successor->rb_right; 228 WRITE_ONCE(parent->rb_left, child2); 229 WRITE_ONCE(successor->rb_right, child); 230 rb_set_parent(child, successor); 231 232 augment->copy(node, successor); 233 augment->propagate(parent, successor); 234 } 235 236 tmp = node->rb_left; 237 WRITE_ONCE(successor->rb_left, tmp); 238 rb_set_parent(tmp, successor); 239 240 pc = node->__rb_parent_color; 241 tmp = __rb_parent(pc); 242 __rb_change_child(node, successor, tmp, root); 243 244 if (child2) { 245 successor->__rb_parent_color = pc; 246 rb_set_parent_color(child2, parent, RB_BLACK); 247 rebalance = NULL; 248 } else { 249 unsigned long pc2 = successor->__rb_parent_color; 250 successor->__rb_parent_color = pc; 251 rebalance = __rb_is_black(pc2) ? parent : NULL; 252 } 253 tmp = successor; 254 } 255 256 augment->propagate(tmp, NULL); 257 return rebalance; 258 } 259 260 static __always_inline void 261 rb_erase_augmented(struct rb_node *node, struct rb_root *root, 262 const struct rb_augment_callbacks *augment) 263 { 264 struct rb_node *rebalance = __rb_erase_augmented(node, root, 265 NULL, augment); 266 if (rebalance) 267 __rb_erase_color(rebalance, root, augment->rotate); 268 } 269 270 static __always_inline void 271 rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root, 272 const struct rb_augment_callbacks *augment) 273 { 274 struct rb_node *rebalance = __rb_erase_augmented(node, &root->rb_root, 275 &root->rb_leftmost, 276 augment); 277 if (rebalance) 278 __rb_erase_color(rebalance, &root->rb_root, augment->rotate); 279 } 280 281 #endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */ 282