| 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| 2 | /* |
| 3 | Red Black Trees |
| 4 | (C) 1999 Andrea Arcangeli <andrea@suse.de> |
| 5 | (C) 2002 David Woodhouse <dwmw2@infradead.org> |
| 6 | (C) 2012 Michel Lespinasse <walken@google.com> |
| 7 | |
| 8 | |
| 9 | tools/linux/include/linux/rbtree_augmented.h |
| 10 | |
| 11 | Copied from: |
| 12 | linux/include/linux/rbtree_augmented.h |
| 13 | */ |
| 14 | |
| 15 | #ifndef _TOOLS_LINUX_RBTREE_AUGMENTED_H |
| 16 | #define _TOOLS_LINUX_RBTREE_AUGMENTED_H |
| 17 | |
| 18 | #include <linux/compiler.h> |
| 19 | #include <linux/rbtree.h> |
| 20 | |
| 21 | /* |
| 22 | * Please note - only struct rb_augment_callbacks and the prototypes for |
| 23 | * rb_insert_augmented() and rb_erase_augmented() are intended to be public. |
| 24 | * The rest are implementation details you are not expected to depend on. |
| 25 | * |
| 26 | * See Documentation/core-api/rbtree.rst for documentation and samples. |
| 27 | */ |
| 28 | |
| 29 | struct rb_augment_callbacks { |
| 30 | void (*propagate)(struct rb_node *node, struct rb_node *stop); |
| 31 | void (*copy)(struct rb_node *old, struct rb_node *new); |
| 32 | void (*rotate)(struct rb_node *old, struct rb_node *new); |
| 33 | }; |
| 34 | |
| 35 | extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, |
| 36 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); |
| 37 | |
| 38 | /* |
| 39 | * Fixup the rbtree and update the augmented information when rebalancing. |
| 40 | * |
| 41 | * On insertion, the user must update the augmented information on the path |
| 42 | * leading to the inserted node, then call rb_link_node() as usual and |
| 43 | * rb_insert_augmented() instead of the usual rb_insert_color() call. |
| 44 | * If rb_insert_augmented() rebalances the rbtree, it will callback into |
| 45 | * a user provided function to update the augmented information on the |
| 46 | * affected subtrees. |
| 47 | */ |
| 48 | static inline void |
| 49 | rb_insert_augmented(struct rb_node *node, struct rb_root *root, |
| 50 | const struct rb_augment_callbacks *augment) |
| 51 | { |
| 52 | __rb_insert_augmented(node, root, augment->rotate); |
| 53 | } |
| 54 | |
| 55 | static inline void |
| 56 | rb_insert_augmented_cached(struct rb_node *node, |
| 57 | struct rb_root_cached *root, bool newleft, |
| 58 | const struct rb_augment_callbacks *augment) |
| 59 | { |
| 60 | if (newleft) |
| 61 | root->rb_leftmost = node; |
| 62 | rb_insert_augmented(node, &root->rb_root, augment); |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * Template for declaring augmented rbtree callbacks (generic case) |
| 67 | * |
| 68 | * RBSTATIC: 'static' or empty |
| 69 | * RBNAME: name of the rb_augment_callbacks structure |
| 70 | * RBSTRUCT: struct type of the tree nodes |
| 71 | * RBFIELD: name of struct rb_node field within RBSTRUCT |
| 72 | * RBAUGMENTED: name of field within RBSTRUCT holding data for subtree |
| 73 | * RBCOMPUTE: name of function that recomputes the RBAUGMENTED data |
| 74 | */ |
| 75 | |
| 76 | #define RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \ |
| 77 | RBSTRUCT, RBFIELD, RBAUGMENTED, RBCOMPUTE) \ |
| 78 | static inline void \ |
| 79 | RBNAME ## _propagate(struct rb_node *rb, struct rb_node *stop) \ |
| 80 | { \ |
| 81 | while (rb != stop) { \ |
| 82 | RBSTRUCT *node = rb_entry(rb, RBSTRUCT, RBFIELD); \ |
| 83 | if (RBCOMPUTE(node, true)) \ |
| 84 | break; \ |
| 85 | rb = rb_parent(&node->RBFIELD); \ |
| 86 | } \ |
| 87 | } \ |
| 88 | static inline void \ |
| 89 | RBNAME ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ |
| 90 | { \ |
| 91 | RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \ |
| 92 | RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \ |
| 93 | new->RBAUGMENTED = old->RBAUGMENTED; \ |
| 94 | } \ |
| 95 | static void \ |
| 96 | RBNAME ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ |
| 97 | { \ |
| 98 | RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \ |
| 99 | RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \ |
| 100 | new->RBAUGMENTED = old->RBAUGMENTED; \ |
| 101 | RBCOMPUTE(old, false); \ |
| 102 | } \ |
| 103 | RBSTATIC const struct rb_augment_callbacks RBNAME = { \ |
| 104 | .propagate = RBNAME ## _propagate, \ |
| 105 | .copy = RBNAME ## _copy, \ |
| 106 | .rotate = RBNAME ## _rotate \ |
| 107 | }; |
| 108 | |
| 109 | /* |
| 110 | * Template for declaring augmented rbtree callbacks, |
| 111 | * computing RBAUGMENTED scalar as max(RBCOMPUTE(node)) for all subtree nodes. |
| 112 | * |
| 113 | * RBSTATIC: 'static' or empty |
| 114 | * RBNAME: name of the rb_augment_callbacks structure |
| 115 | * RBSTRUCT: struct type of the tree nodes |
| 116 | * RBFIELD: name of struct rb_node field within RBSTRUCT |
| 117 | * RBTYPE: type of the RBAUGMENTED field |
| 118 | * RBAUGMENTED: name of RBTYPE field within RBSTRUCT holding data for subtree |
| 119 | * RBCOMPUTE: name of function that returns the per-node RBTYPE scalar |
| 120 | */ |
| 121 | |
| 122 | #define RB_DECLARE_CALLBACKS_MAX(RBSTATIC, RBNAME, RBSTRUCT, RBFIELD, \ |
| 123 | RBTYPE, RBAUGMENTED, RBCOMPUTE) \ |
| 124 | static inline bool RBNAME ## _compute_max(RBSTRUCT *node, bool exit) \ |
| 125 | { \ |
| 126 | RBSTRUCT *child; \ |
| 127 | RBTYPE max = RBCOMPUTE(node); \ |
| 128 | if (node->RBFIELD.rb_left) { \ |
| 129 | child = rb_entry(node->RBFIELD.rb_left, RBSTRUCT, RBFIELD); \ |
| 130 | if (child->RBAUGMENTED > max) \ |
| 131 | max = child->RBAUGMENTED; \ |
| 132 | } \ |
| 133 | if (node->RBFIELD.rb_right) { \ |
| 134 | child = rb_entry(node->RBFIELD.rb_right, RBSTRUCT, RBFIELD); \ |
| 135 | if (child->RBAUGMENTED > max) \ |
| 136 | max = child->RBAUGMENTED; \ |
| 137 | } \ |
| 138 | if (exit && node->RBAUGMENTED == max) \ |
| 139 | return true; \ |
| 140 | node->RBAUGMENTED = max; \ |
| 141 | return false; \ |
| 142 | } \ |
| 143 | RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \ |
| 144 | RBSTRUCT, RBFIELD, RBAUGMENTED, RBNAME ## _compute_max) |
| 145 | |
| 146 | |
| 147 | #define RB_RED 0 |
| 148 | #define RB_BLACK 1 |
| 149 | |
| 150 | #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) |
| 151 | |
| 152 | #define __rb_color(pc) ((pc) & 1) |
| 153 | #define __rb_is_black(pc) __rb_color(pc) |
| 154 | #define __rb_is_red(pc) (!__rb_color(pc)) |
| 155 | #define rb_color(rb) __rb_color((rb)->__rb_parent_color) |
| 156 | #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) |
| 157 | #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) |
| 158 | |
| 159 | static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) |
| 160 | { |
| 161 | rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; |
| 162 | } |
| 163 | |
| 164 | static inline void rb_set_parent_color(struct rb_node *rb, |
| 165 | struct rb_node *p, int color) |
| 166 | { |
| 167 | rb->__rb_parent_color = (unsigned long)p | color; |
| 168 | } |
| 169 | |
| 170 | static inline void |
| 171 | __rb_change_child(struct rb_node *old, struct rb_node *new, |
| 172 | struct rb_node *parent, struct rb_root *root) |
| 173 | { |
| 174 | if (parent) { |
| 175 | if (parent->rb_left == old) |
| 176 | WRITE_ONCE(parent->rb_left, new); |
| 177 | else |
| 178 | WRITE_ONCE(parent->rb_right, new); |
| 179 | } else |
| 180 | WRITE_ONCE(root->rb_node, new); |
| 181 | } |
| 182 | |
| 183 | extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, |
| 184 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); |
| 185 | |
| 186 | static __always_inline struct rb_node * |
| 187 | __rb_erase_augmented(struct rb_node *node, struct rb_root *root, |
| 188 | const struct rb_augment_callbacks *augment) |
| 189 | { |
| 190 | struct rb_node *child = node->rb_right; |
| 191 | struct rb_node *tmp = node->rb_left; |
| 192 | struct rb_node *parent, *rebalance; |
| 193 | unsigned long pc; |
| 194 | |
| 195 | if (!tmp) { |
| 196 | /* |
| 197 | * Case 1: node to erase has no more than 1 child (easy!) |
| 198 | * |
| 199 | * Note that if there is one child it must be red due to 5) |
| 200 | * and node must be black due to 4). We adjust colors locally |
| 201 | * so as to bypass __rb_erase_color() later on. |
| 202 | */ |
| 203 | pc = node->__rb_parent_color; |
| 204 | parent = __rb_parent(pc); |
| 205 | __rb_change_child(node, child, parent, root); |
| 206 | if (child) { |
| 207 | child->__rb_parent_color = pc; |
| 208 | rebalance = NULL; |
| 209 | } else |
| 210 | rebalance = __rb_is_black(pc) ? parent : NULL; |
| 211 | tmp = parent; |
| 212 | } else if (!child) { |
| 213 | /* Still case 1, but this time the child is node->rb_left */ |
| 214 | tmp->__rb_parent_color = pc = node->__rb_parent_color; |
| 215 | parent = __rb_parent(pc); |
| 216 | __rb_change_child(node, tmp, parent, root); |
| 217 | rebalance = NULL; |
| 218 | tmp = parent; |
| 219 | } else { |
| 220 | struct rb_node *successor = child, *child2; |
| 221 | |
| 222 | tmp = child->rb_left; |
| 223 | if (!tmp) { |
| 224 | /* |
| 225 | * Case 2: node's successor is its right child |
| 226 | * |
| 227 | * (n) (s) |
| 228 | * / \ / \ |
| 229 | * (x) (s) -> (x) (c) |
| 230 | * \ |
| 231 | * (c) |
| 232 | */ |
| 233 | parent = successor; |
| 234 | child2 = successor->rb_right; |
| 235 | |
| 236 | augment->copy(node, successor); |
| 237 | } else { |
| 238 | /* |
| 239 | * Case 3: node's successor is leftmost under |
| 240 | * node's right child subtree |
| 241 | * |
| 242 | * (n) (s) |
| 243 | * / \ / \ |
| 244 | * (x) (y) -> (x) (y) |
| 245 | * / / |
| 246 | * (p) (p) |
| 247 | * / / |
| 248 | * (s) (c) |
| 249 | * \ |
| 250 | * (c) |
| 251 | */ |
| 252 | do { |
| 253 | parent = successor; |
| 254 | successor = tmp; |
| 255 | tmp = tmp->rb_left; |
| 256 | } while (tmp); |
| 257 | child2 = successor->rb_right; |
| 258 | WRITE_ONCE(parent->rb_left, child2); |
| 259 | WRITE_ONCE(successor->rb_right, child); |
| 260 | rb_set_parent(child, successor); |
| 261 | |
| 262 | augment->copy(node, successor); |
| 263 | augment->propagate(parent, successor); |
| 264 | } |
| 265 | |
| 266 | tmp = node->rb_left; |
| 267 | WRITE_ONCE(successor->rb_left, tmp); |
| 268 | rb_set_parent(tmp, successor); |
| 269 | |
| 270 | pc = node->__rb_parent_color; |
| 271 | tmp = __rb_parent(pc); |
| 272 | __rb_change_child(node, successor, tmp, root); |
| 273 | |
| 274 | if (child2) { |
| 275 | successor->__rb_parent_color = pc; |
| 276 | rb_set_parent_color(child2, parent, RB_BLACK); |
| 277 | rebalance = NULL; |
| 278 | } else { |
| 279 | unsigned long pc2 = successor->__rb_parent_color; |
| 280 | successor->__rb_parent_color = pc; |
| 281 | rebalance = __rb_is_black(pc2) ? parent : NULL; |
| 282 | } |
| 283 | tmp = successor; |
| 284 | } |
| 285 | |
| 286 | augment->propagate(tmp, NULL); |
| 287 | return rebalance; |
| 288 | } |
| 289 | |
| 290 | static __always_inline void |
| 291 | rb_erase_augmented(struct rb_node *node, struct rb_root *root, |
| 292 | const struct rb_augment_callbacks *augment) |
| 293 | { |
| 294 | struct rb_node *rebalance = __rb_erase_augmented(node, root, augment); |
| 295 | if (rebalance) |
| 296 | __rb_erase_color(rebalance, root, augment->rotate); |
| 297 | } |
| 298 | |
| 299 | static __always_inline void |
| 300 | rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root, |
| 301 | const struct rb_augment_callbacks *augment) |
| 302 | { |
| 303 | if (root->rb_leftmost == node) |
| 304 | root->rb_leftmost = rb_next(node); |
| 305 | rb_erase_augmented(node, &root->rb_root, augment); |
| 306 | } |
| 307 | |
| 308 | #endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */ |