Arnaldo Carvalho de Melo | 307bc97 | 2015-07-05 22:59:05 -0300 | [diff] [blame] | 1 | /* |
| 2 | Red Black Trees |
| 3 | (C) 1999 Andrea Arcangeli <andrea@suse.de> |
| 4 | (C) 2002 David Woodhouse <dwmw2@infradead.org> |
| 5 | (C) 2012 Michel Lespinasse <walken@google.com> |
| 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 */ |