bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 1 | /* |
epoger@google.com | ec3ed6a | 2011-07-28 14:26:00 +0000 | [diff] [blame] | 2 | * Copyright 2011 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 6 | */ |
| 7 | |
| 8 | #ifndef GrRedBlackTree_DEFINED |
| 9 | #define GrRedBlackTree_DEFINED |
| 10 | |
tfarina@chromium.org | 68f3a3e | 2014-01-29 23:56:40 +0000 | [diff] [blame] | 11 | #include "GrConfig.h" |
commit-bot@chromium.org | a0b4028 | 2013-09-18 13:00:55 +0000 | [diff] [blame] | 12 | #include "SkTypes.h" |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 13 | |
| 14 | template <typename T> |
| 15 | class GrLess { |
| 16 | public: |
| 17 | bool operator()(const T& a, const T& b) const { return a < b; } |
| 18 | }; |
| 19 | |
| 20 | template <typename T> |
| 21 | class GrLess<T*> { |
| 22 | public: |
| 23 | bool operator()(const T* a, const T* b) const { return *a < *b; } |
| 24 | }; |
| 25 | |
commit-bot@chromium.org | 4fcc3ca | 2014-02-27 20:23:22 +0000 | [diff] [blame] | 26 | class GrStrLess { |
| 27 | public: |
| 28 | bool operator()(const char* a, const char* b) const { return strcmp(a,b) < 0; } |
| 29 | }; |
| 30 | |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 31 | /** |
| 32 | * In debug build this will cause full traversals of the tree when the validate |
| 33 | * is called on insert and remove. Useful for debugging but very slow. |
| 34 | */ |
| 35 | #define DEEP_VALIDATE 0 |
| 36 | |
| 37 | /** |
| 38 | * A sorted tree that uses the red-black tree algorithm. Allows duplicate |
| 39 | * entries. Data is of type T and is compared using functor C. A single C object |
| 40 | * will be created and used for all comparisons. |
| 41 | */ |
| 42 | template <typename T, typename C = GrLess<T> > |
commit-bot@chromium.org | e3beb6b | 2014-04-07 19:34:38 +0000 | [diff] [blame] | 43 | class GrRedBlackTree : SkNoncopyable { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 44 | public: |
| 45 | /** |
| 46 | * Creates an empty tree. |
| 47 | */ |
| 48 | GrRedBlackTree(); |
| 49 | virtual ~GrRedBlackTree(); |
| 50 | |
| 51 | /** |
| 52 | * Class used to iterater through the tree. The valid range of the tree |
| 53 | * is given by [begin(), end()). It is legal to dereference begin() but not |
| 54 | * end(). The iterator has preincrement and predecrement operators, it is |
| 55 | * legal to decerement end() if the tree is not empty to get the last |
| 56 | * element. However, a last() helper is provided. |
| 57 | */ |
| 58 | class Iter; |
| 59 | |
| 60 | /** |
| 61 | * Add an element to the tree. Duplicates are allowed. |
| 62 | * @param t the item to add. |
| 63 | * @return an iterator to the item. |
| 64 | */ |
| 65 | Iter insert(const T& t); |
| 66 | |
| 67 | /** |
| 68 | * Removes all items in the tree. |
| 69 | */ |
| 70 | void reset(); |
| 71 | |
| 72 | /** |
| 73 | * @return true if there are no items in the tree, false otherwise. |
| 74 | */ |
| 75 | bool empty() const {return 0 == fCount;} |
| 76 | |
| 77 | /** |
| 78 | * @return the number of items in the tree. |
| 79 | */ |
| 80 | int count() const {return fCount;} |
| 81 | |
| 82 | /** |
| 83 | * @return an iterator to the first item in sorted order, or end() if empty |
| 84 | */ |
| 85 | Iter begin(); |
| 86 | /** |
| 87 | * Gets the last valid iterator. This is always valid, even on an empty. |
| 88 | * However, it can never be dereferenced. Useful as a loop terminator. |
| 89 | * @return an iterator that is just beyond the last item in sorted order. |
| 90 | */ |
| 91 | Iter end(); |
| 92 | /** |
| 93 | * @return an iterator that to the last item in sorted order, or end() if |
| 94 | * empty. |
| 95 | */ |
| 96 | Iter last(); |
| 97 | |
| 98 | /** |
| 99 | * Finds an occurrence of an item. |
| 100 | * @param t the item to find. |
| 101 | * @return an iterator to a tree element equal to t or end() if none exists. |
| 102 | */ |
| 103 | Iter find(const T& t); |
| 104 | /** |
| 105 | * Finds the first of an item in iterator order. |
| 106 | * @param t the item to find. |
| 107 | * @return an iterator to the first element equal to t or end() if |
| 108 | * none exists. |
| 109 | */ |
| 110 | Iter findFirst(const T& t); |
| 111 | /** |
| 112 | * Finds the last of an item in iterator order. |
| 113 | * @param t the item to find. |
| 114 | * @return an iterator to the last element equal to t or end() if |
| 115 | * none exists. |
| 116 | */ |
| 117 | Iter findLast(const T& t); |
| 118 | /** |
| 119 | * Gets the number of items in the tree equal to t. |
| 120 | * @param t the item to count. |
| 121 | * @return number of items equal to t in the tree |
| 122 | */ |
| 123 | int countOf(const T& t) const; |
| 124 | |
| 125 | /** |
| 126 | * Removes the item indicated by an iterator. The iterator will not be valid |
| 127 | * afterwards. |
| 128 | * |
| 129 | * @param iter iterator of item to remove. Must be valid (not end()). |
| 130 | */ |
| 131 | void remove(const Iter& iter) { deleteAtNode(iter.fN); } |
| 132 | |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 133 | private: |
| 134 | enum Color { |
| 135 | kRed_Color, |
| 136 | kBlack_Color |
| 137 | }; |
| 138 | |
| 139 | enum Child { |
| 140 | kLeft_Child = 0, |
| 141 | kRight_Child = 1 |
| 142 | }; |
| 143 | |
| 144 | struct Node { |
| 145 | T fItem; |
| 146 | Color fColor; |
| 147 | |
| 148 | Node* fParent; |
| 149 | Node* fChildren[2]; |
| 150 | }; |
| 151 | |
| 152 | void rotateRight(Node* n); |
| 153 | void rotateLeft(Node* n); |
| 154 | |
| 155 | static Node* SuccessorNode(Node* x); |
| 156 | static Node* PredecessorNode(Node* x); |
| 157 | |
| 158 | void deleteAtNode(Node* x); |
| 159 | static void RecursiveDelete(Node* x); |
| 160 | |
bsalomon@google.com | bcdbbe6 | 2011-04-12 15:40:00 +0000 | [diff] [blame] | 161 | int onCountOf(const Node* n, const T& t) const; |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 162 | |
commit-bot@chromium.org | 515dcd3 | 2013-08-28 14:17:03 +0000 | [diff] [blame] | 163 | #ifdef SK_DEBUG |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 164 | void validate() const; |
| 165 | int checkNode(Node* n, int* blackHeight) const; |
| 166 | // checks relationship between a node and its children. allowRedRed means |
| 167 | // node may be in an intermediate state where a red parent has a red child. |
| 168 | bool validateChildRelations(const Node* n, bool allowRedRed) const; |
| 169 | // place to stick break point if validateChildRelations is failing. |
| 170 | bool validateChildRelationsFailed() const { return false; } |
| 171 | #else |
| 172 | void validate() const {} |
| 173 | #endif |
| 174 | |
| 175 | int fCount; |
| 176 | Node* fRoot; |
| 177 | Node* fFirst; |
| 178 | Node* fLast; |
| 179 | |
| 180 | const C fComp; |
| 181 | }; |
| 182 | |
| 183 | template <typename T, typename C> |
| 184 | class GrRedBlackTree<T,C>::Iter { |
| 185 | public: |
| 186 | Iter() {}; |
| 187 | Iter(const Iter& i) {fN = i.fN; fTree = i.fTree;} |
| 188 | Iter& operator =(const Iter& i) { |
| 189 | fN = i.fN; |
| 190 | fTree = i.fTree; |
| 191 | return *this; |
| 192 | } |
| 193 | // altering the sort value of the item using this method will cause |
| 194 | // errors. |
| 195 | T& operator *() const { return fN->fItem; } |
| 196 | bool operator ==(const Iter& i) const { |
| 197 | return fN == i.fN && fTree == i.fTree; |
| 198 | } |
| 199 | bool operator !=(const Iter& i) const { return !(*this == i); } |
| 200 | Iter& operator ++() { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 201 | SkASSERT(*this != fTree->end()); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 202 | fN = SuccessorNode(fN); |
| 203 | return *this; |
| 204 | } |
| 205 | Iter& operator --() { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 206 | SkASSERT(*this != fTree->begin()); |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 207 | if (fN) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 208 | fN = PredecessorNode(fN); |
| 209 | } else { |
| 210 | *this = fTree->last(); |
| 211 | } |
| 212 | return *this; |
| 213 | } |
| 214 | |
| 215 | private: |
| 216 | friend class GrRedBlackTree; |
| 217 | explicit Iter(Node* n, GrRedBlackTree* tree) { |
| 218 | fN = n; |
| 219 | fTree = tree; |
| 220 | } |
| 221 | Node* fN; |
| 222 | GrRedBlackTree* fTree; |
| 223 | }; |
| 224 | |
| 225 | template <typename T, typename C> |
| 226 | GrRedBlackTree<T,C>::GrRedBlackTree() : fComp() { |
| 227 | fRoot = NULL; |
| 228 | fFirst = NULL; |
| 229 | fLast = NULL; |
| 230 | fCount = 0; |
| 231 | validate(); |
| 232 | } |
| 233 | |
| 234 | template <typename T, typename C> |
| 235 | GrRedBlackTree<T,C>::~GrRedBlackTree() { |
| 236 | RecursiveDelete(fRoot); |
| 237 | } |
| 238 | |
| 239 | template <typename T, typename C> |
| 240 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::begin() { |
| 241 | return Iter(fFirst, this); |
| 242 | } |
| 243 | |
| 244 | template <typename T, typename C> |
| 245 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::end() { |
| 246 | return Iter(NULL, this); |
| 247 | } |
| 248 | |
| 249 | template <typename T, typename C> |
| 250 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::last() { |
| 251 | return Iter(fLast, this); |
| 252 | } |
| 253 | |
| 254 | template <typename T, typename C> |
| 255 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::find(const T& t) { |
| 256 | Node* n = fRoot; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 257 | while (n) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 258 | if (fComp(t, n->fItem)) { |
| 259 | n = n->fChildren[kLeft_Child]; |
| 260 | } else { |
| 261 | if (!fComp(n->fItem, t)) { |
| 262 | return Iter(n, this); |
| 263 | } |
| 264 | n = n->fChildren[kRight_Child]; |
| 265 | } |
| 266 | } |
| 267 | return end(); |
| 268 | } |
| 269 | |
| 270 | template <typename T, typename C> |
| 271 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::findFirst(const T& t) { |
| 272 | Node* n = fRoot; |
| 273 | Node* leftMost = NULL; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 274 | while (n) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 275 | if (fComp(t, n->fItem)) { |
| 276 | n = n->fChildren[kLeft_Child]; |
| 277 | } else { |
| 278 | if (!fComp(n->fItem, t)) { |
| 279 | // found one. check if another in left subtree. |
| 280 | leftMost = n; |
| 281 | n = n->fChildren[kLeft_Child]; |
| 282 | } else { |
| 283 | n = n->fChildren[kRight_Child]; |
| 284 | } |
| 285 | } |
| 286 | } |
| 287 | return Iter(leftMost, this); |
| 288 | } |
| 289 | |
| 290 | template <typename T, typename C> |
| 291 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::findLast(const T& t) { |
| 292 | Node* n = fRoot; |
| 293 | Node* rightMost = NULL; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 294 | while (n) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 295 | if (fComp(t, n->fItem)) { |
| 296 | n = n->fChildren[kLeft_Child]; |
| 297 | } else { |
| 298 | if (!fComp(n->fItem, t)) { |
| 299 | // found one. check if another in right subtree. |
| 300 | rightMost = n; |
| 301 | } |
| 302 | n = n->fChildren[kRight_Child]; |
| 303 | } |
| 304 | } |
| 305 | return Iter(rightMost, this); |
| 306 | } |
| 307 | |
| 308 | template <typename T, typename C> |
| 309 | int GrRedBlackTree<T,C>::countOf(const T& t) const { |
bsalomon@google.com | bcdbbe6 | 2011-04-12 15:40:00 +0000 | [diff] [blame] | 310 | return onCountOf(fRoot, t); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 311 | } |
| 312 | |
| 313 | template <typename T, typename C> |
bsalomon@google.com | bcdbbe6 | 2011-04-12 15:40:00 +0000 | [diff] [blame] | 314 | int GrRedBlackTree<T,C>::onCountOf(const Node* n, const T& t) const { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 315 | // this is count*log(n) :( |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 316 | while (n) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 317 | if (fComp(t, n->fItem)) { |
| 318 | n = n->fChildren[kLeft_Child]; |
| 319 | } else { |
| 320 | if (!fComp(n->fItem, t)) { |
| 321 | int count = 1; |
bsalomon@google.com | bcdbbe6 | 2011-04-12 15:40:00 +0000 | [diff] [blame] | 322 | count += onCountOf(n->fChildren[kLeft_Child], t); |
| 323 | count += onCountOf(n->fChildren[kRight_Child], t); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 324 | return count; |
| 325 | } |
| 326 | n = n->fChildren[kRight_Child]; |
| 327 | } |
| 328 | } |
| 329 | return 0; |
| 330 | |
| 331 | } |
| 332 | |
| 333 | template <typename T, typename C> |
| 334 | void GrRedBlackTree<T,C>::reset() { |
| 335 | RecursiveDelete(fRoot); |
| 336 | fRoot = NULL; |
| 337 | fFirst = NULL; |
| 338 | fLast = NULL; |
| 339 | fCount = 0; |
| 340 | } |
| 341 | |
| 342 | template <typename T, typename C> |
| 343 | typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::insert(const T& t) { |
| 344 | validate(); |
| 345 | |
| 346 | ++fCount; |
| 347 | |
tomhudson@google.com | c377baf | 2012-07-09 20:17:56 +0000 | [diff] [blame] | 348 | Node* x = SkNEW(Node); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 349 | x->fChildren[kLeft_Child] = NULL; |
| 350 | x->fChildren[kRight_Child] = NULL; |
| 351 | x->fItem = t; |
| 352 | |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 353 | Node* returnNode = x; |
| 354 | |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 355 | Node* gp = NULL; |
| 356 | Node* p = NULL; |
| 357 | Node* n = fRoot; |
bsalomon@google.com | ba9d628 | 2011-02-22 19:45:21 +0000 | [diff] [blame] | 358 | Child pc = kLeft_Child; // suppress uninit warning |
tomhudson@google.com | 2c2508d | 2011-07-29 13:44:30 +0000 | [diff] [blame] | 359 | Child gpc = kLeft_Child; |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 360 | |
| 361 | bool first = true; |
| 362 | bool last = true; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 363 | while (n) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 364 | gpc = pc; |
| 365 | pc = fComp(x->fItem, n->fItem) ? kLeft_Child : kRight_Child; |
| 366 | first = first && kLeft_Child == pc; |
| 367 | last = last && kRight_Child == pc; |
| 368 | gp = p; |
| 369 | p = n; |
| 370 | n = p->fChildren[pc]; |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 371 | } |
| 372 | if (last) { |
| 373 | fLast = x; |
| 374 | } |
| 375 | if (first) { |
| 376 | fFirst = x; |
| 377 | } |
| 378 | |
| 379 | if (NULL == p) { |
| 380 | fRoot = x; |
| 381 | x->fColor = kBlack_Color; |
| 382 | x->fParent = NULL; |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 383 | SkASSERT(1 == fCount); |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 384 | return Iter(returnNode, this); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 385 | } |
| 386 | p->fChildren[pc] = x; |
| 387 | x->fColor = kRed_Color; |
| 388 | x->fParent = p; |
| 389 | |
| 390 | do { |
| 391 | // assumptions at loop start. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 392 | SkASSERT(x); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 393 | SkASSERT(kRed_Color == x->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 394 | // can't have a grandparent but no parent. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 395 | SkASSERT(!(gp && NULL == p)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 396 | // make sure pc and gpc are correct |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 397 | SkASSERT(NULL == p || p->fChildren[pc] == x); |
| 398 | SkASSERT(NULL == gp || gp->fChildren[gpc] == p); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 399 | |
| 400 | // if x's parent is black then we didn't violate any of the |
| 401 | // red/black properties when we added x as red. |
| 402 | if (kBlack_Color == p->fColor) { |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 403 | return Iter(returnNode, this); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 404 | } |
| 405 | // gp must be valid because if p was the root then it is black |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 406 | SkASSERT(gp); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 407 | // gp must be black since it's child, p, is red. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 408 | SkASSERT(kBlack_Color == gp->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 409 | |
| 410 | |
| 411 | // x and its parent are red, violating red-black property. |
| 412 | Node* u = gp->fChildren[1-gpc]; |
| 413 | // if x's uncle (p's sibling) is also red then we can flip |
| 414 | // p and u to black and make gp red. But then we have to recurse |
| 415 | // up to gp since it's parent may also be red. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 416 | if (u && kRed_Color == u->fColor) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 417 | p->fColor = kBlack_Color; |
| 418 | u->fColor = kBlack_Color; |
| 419 | gp->fColor = kRed_Color; |
| 420 | x = gp; |
| 421 | p = x->fParent; |
| 422 | if (NULL == p) { |
| 423 | // x (prev gp) is the root, color it black and be done. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 424 | SkASSERT(fRoot == x); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 425 | x->fColor = kBlack_Color; |
| 426 | validate(); |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 427 | return Iter(returnNode, this); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 428 | } |
| 429 | gp = p->fParent; |
| 430 | pc = (p->fChildren[kLeft_Child] == x) ? kLeft_Child : |
| 431 | kRight_Child; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 432 | if (gp) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 433 | gpc = (gp->fChildren[kLeft_Child] == p) ? kLeft_Child : |
| 434 | kRight_Child; |
| 435 | } |
| 436 | continue; |
| 437 | } break; |
| 438 | } while (true); |
| 439 | // Here p is red but u is black and we still have to resolve the fact |
| 440 | // that x and p are both red. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 441 | SkASSERT(NULL == gp->fChildren[1-gpc] || kBlack_Color == gp->fChildren[1-gpc]->fColor); |
| 442 | SkASSERT(kRed_Color == x->fColor); |
| 443 | SkASSERT(kRed_Color == p->fColor); |
| 444 | SkASSERT(kBlack_Color == gp->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 445 | |
| 446 | // make x be on the same side of p as p is of gp. If it isn't already |
| 447 | // the case then rotate x up to p and swap their labels. |
| 448 | if (pc != gpc) { |
| 449 | if (kRight_Child == pc) { |
| 450 | rotateLeft(p); |
| 451 | Node* temp = p; |
| 452 | p = x; |
| 453 | x = temp; |
| 454 | pc = kLeft_Child; |
| 455 | } else { |
| 456 | rotateRight(p); |
| 457 | Node* temp = p; |
| 458 | p = x; |
| 459 | x = temp; |
| 460 | pc = kRight_Child; |
| 461 | } |
| 462 | } |
| 463 | // we now rotate gp down, pulling up p to be it's new parent. |
| 464 | // gp's child, u, that is not affected we know to be black. gp's new |
| 465 | // child is p's previous child (x's pre-rotation sibling) which must be |
| 466 | // black since p is red. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 467 | SkASSERT(NULL == p->fChildren[1-pc] || |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 468 | kBlack_Color == p->fChildren[1-pc]->fColor); |
| 469 | // Since gp's two children are black it can become red if p is made |
| 470 | // black. This leaves the black-height of both of p's new subtrees |
| 471 | // preserved and removes the red/red parent child relationship. |
| 472 | p->fColor = kBlack_Color; |
| 473 | gp->fColor = kRed_Color; |
| 474 | if (kLeft_Child == pc) { |
| 475 | rotateRight(gp); |
| 476 | } else { |
| 477 | rotateLeft(gp); |
| 478 | } |
| 479 | validate(); |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 480 | return Iter(returnNode, this); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 481 | } |
| 482 | |
| 483 | |
| 484 | template <typename T, typename C> |
| 485 | void GrRedBlackTree<T,C>::rotateRight(Node* n) { |
| 486 | /* d? d? |
| 487 | * / / |
| 488 | * n s |
| 489 | * / \ ---> / \ |
| 490 | * s a? c? n |
| 491 | * / \ / \ |
| 492 | * c? b? b? a? |
| 493 | */ |
| 494 | Node* d = n->fParent; |
| 495 | Node* s = n->fChildren[kLeft_Child]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 496 | SkASSERT(s); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 497 | Node* b = s->fChildren[kRight_Child]; |
| 498 | |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 499 | if (d) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 500 | Child c = d->fChildren[kLeft_Child] == n ? kLeft_Child : |
| 501 | kRight_Child; |
| 502 | d->fChildren[c] = s; |
| 503 | } else { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 504 | SkASSERT(fRoot == n); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 505 | fRoot = s; |
| 506 | } |
| 507 | s->fParent = d; |
| 508 | s->fChildren[kRight_Child] = n; |
| 509 | n->fParent = s; |
| 510 | n->fChildren[kLeft_Child] = b; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 511 | if (b) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 512 | b->fParent = n; |
| 513 | } |
| 514 | |
| 515 | GR_DEBUGASSERT(validateChildRelations(d, true)); |
| 516 | GR_DEBUGASSERT(validateChildRelations(s, true)); |
| 517 | GR_DEBUGASSERT(validateChildRelations(n, false)); |
| 518 | GR_DEBUGASSERT(validateChildRelations(n->fChildren[kRight_Child], true)); |
| 519 | GR_DEBUGASSERT(validateChildRelations(b, true)); |
| 520 | GR_DEBUGASSERT(validateChildRelations(s->fChildren[kLeft_Child], true)); |
| 521 | } |
| 522 | |
| 523 | template <typename T, typename C> |
| 524 | void GrRedBlackTree<T,C>::rotateLeft(Node* n) { |
| 525 | |
| 526 | Node* d = n->fParent; |
| 527 | Node* s = n->fChildren[kRight_Child]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 528 | SkASSERT(s); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 529 | Node* b = s->fChildren[kLeft_Child]; |
| 530 | |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 531 | if (d) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 532 | Child c = d->fChildren[kRight_Child] == n ? kRight_Child : |
| 533 | kLeft_Child; |
| 534 | d->fChildren[c] = s; |
| 535 | } else { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 536 | SkASSERT(fRoot == n); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 537 | fRoot = s; |
| 538 | } |
| 539 | s->fParent = d; |
| 540 | s->fChildren[kLeft_Child] = n; |
| 541 | n->fParent = s; |
| 542 | n->fChildren[kRight_Child] = b; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 543 | if (b) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 544 | b->fParent = n; |
| 545 | } |
| 546 | |
| 547 | GR_DEBUGASSERT(validateChildRelations(d, true)); |
| 548 | GR_DEBUGASSERT(validateChildRelations(s, true)); |
| 549 | GR_DEBUGASSERT(validateChildRelations(n, true)); |
| 550 | GR_DEBUGASSERT(validateChildRelations(n->fChildren[kLeft_Child], true)); |
| 551 | GR_DEBUGASSERT(validateChildRelations(b, true)); |
| 552 | GR_DEBUGASSERT(validateChildRelations(s->fChildren[kRight_Child], true)); |
| 553 | } |
| 554 | |
| 555 | template <typename T, typename C> |
| 556 | typename GrRedBlackTree<T,C>::Node* GrRedBlackTree<T,C>::SuccessorNode(Node* x) { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 557 | SkASSERT(x); |
| 558 | if (x->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 559 | x = x->fChildren[kRight_Child]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 560 | while (x->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 561 | x = x->fChildren[kLeft_Child]; |
| 562 | } |
| 563 | return x; |
| 564 | } |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 565 | while (x->fParent && x == x->fParent->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 566 | x = x->fParent; |
| 567 | } |
| 568 | return x->fParent; |
| 569 | } |
| 570 | |
| 571 | template <typename T, typename C> |
| 572 | typename GrRedBlackTree<T,C>::Node* GrRedBlackTree<T,C>::PredecessorNode(Node* x) { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 573 | SkASSERT(x); |
| 574 | if (x->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 575 | x = x->fChildren[kLeft_Child]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 576 | while (x->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 577 | x = x->fChildren[kRight_Child]; |
| 578 | } |
| 579 | return x; |
| 580 | } |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 581 | while (x->fParent && x == x->fParent->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 582 | x = x->fParent; |
| 583 | } |
| 584 | return x->fParent; |
| 585 | } |
| 586 | |
| 587 | template <typename T, typename C> |
| 588 | void GrRedBlackTree<T,C>::deleteAtNode(Node* x) { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 589 | SkASSERT(x); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 590 | validate(); |
| 591 | --fCount; |
| 592 | |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 593 | bool hasLeft = SkToBool(x->fChildren[kLeft_Child]); |
| 594 | bool hasRight = SkToBool(x->fChildren[kRight_Child]); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 595 | Child c = hasLeft ? kLeft_Child : kRight_Child; |
| 596 | |
| 597 | if (hasLeft && hasRight) { |
| 598 | // first and last can't have two children. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 599 | SkASSERT(fFirst != x); |
| 600 | SkASSERT(fLast != x); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 601 | // if x is an interior node then we find it's successor |
| 602 | // and swap them. |
| 603 | Node* s = x->fChildren[kRight_Child]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 604 | while (s->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 605 | s = s->fChildren[kLeft_Child]; |
| 606 | } |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 607 | SkASSERT(s); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 608 | // this might be expensive relative to swapping node ptrs around. |
| 609 | // depends on T. |
| 610 | x->fItem = s->fItem; |
| 611 | x = s; |
| 612 | c = kRight_Child; |
| 613 | } else if (NULL == x->fParent) { |
| 614 | // if x was the root we just replace it with its child and make |
| 615 | // the new root (if the tree is not empty) black. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 616 | SkASSERT(fRoot == x); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 617 | fRoot = x->fChildren[c]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 618 | if (fRoot) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 619 | fRoot->fParent = NULL; |
| 620 | fRoot->fColor = kBlack_Color; |
| 621 | if (x == fLast) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 622 | SkASSERT(c == kLeft_Child); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 623 | fLast = fRoot; |
| 624 | } else if (x == fFirst) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 625 | SkASSERT(c == kRight_Child); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 626 | fFirst = fRoot; |
| 627 | } |
| 628 | } else { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 629 | SkASSERT(fFirst == fLast && x == fFirst); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 630 | fFirst = NULL; |
| 631 | fLast = NULL; |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 632 | SkASSERT(0 == fCount); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 633 | } |
| 634 | delete x; |
| 635 | validate(); |
| 636 | return; |
| 637 | } |
| 638 | |
| 639 | Child pc; |
| 640 | Node* p = x->fParent; |
| 641 | pc = p->fChildren[kLeft_Child] == x ? kLeft_Child : kRight_Child; |
| 642 | |
| 643 | if (NULL == x->fChildren[c]) { |
| 644 | if (fLast == x) { |
| 645 | fLast = p; |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 646 | SkASSERT(p == PredecessorNode(x)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 647 | } else if (fFirst == x) { |
| 648 | fFirst = p; |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 649 | SkASSERT(p == SuccessorNode(x)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 650 | } |
| 651 | // x has two implicit black children. |
| 652 | Color xcolor = x->fColor; |
| 653 | p->fChildren[pc] = NULL; |
| 654 | delete x; |
bsalomon@google.com | 5aaa69e | 2011-03-04 20:29:08 +0000 | [diff] [blame] | 655 | x = NULL; |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 656 | // when x is red it can be with an implicit black leaf without |
| 657 | // violating any of the red-black tree properties. |
| 658 | if (kRed_Color == xcolor) { |
| 659 | validate(); |
| 660 | return; |
| 661 | } |
| 662 | // s is p's other child (x's sibling) |
| 663 | Node* s = p->fChildren[1-pc]; |
| 664 | |
| 665 | //s cannot be an implicit black node because the original |
| 666 | // black-height at x was >= 2 and s's black-height must equal the |
| 667 | // initial black height of x. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 668 | SkASSERT(s); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 669 | SkASSERT(p == s->fParent); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 670 | |
| 671 | // assigned in loop |
| 672 | Node* sl; |
| 673 | Node* sr; |
| 674 | bool slRed; |
| 675 | bool srRed; |
| 676 | |
| 677 | do { |
| 678 | // When we start this loop x may already be deleted it is/was |
| 679 | // p's child on its pc side. x's children are/were black. The |
| 680 | // first time through the loop they are implict children. |
| 681 | // On later passes we will be walking up the tree and they will |
| 682 | // be real nodes. |
| 683 | // The x side of p has a black-height that is one less than the |
| 684 | // s side. It must be rebalanced. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 685 | SkASSERT(s); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 686 | SkASSERT(p == s->fParent); |
| 687 | SkASSERT(NULL == x || x->fParent == p); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 688 | |
| 689 | //sl and sr are s's children, which may be implicit. |
| 690 | sl = s->fChildren[kLeft_Child]; |
| 691 | sr = s->fChildren[kRight_Child]; |
| 692 | |
| 693 | // if the s is red we will rotate s and p, swap their colors so |
| 694 | // that x's new sibling is black |
| 695 | if (kRed_Color == s->fColor) { |
| 696 | // if s is red then it's parent must be black. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 697 | SkASSERT(kBlack_Color == p->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 698 | // s's children must also be black since s is red. They can't |
| 699 | // be implicit since s is red and it's black-height is >= 2. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 700 | SkASSERT(sl && kBlack_Color == sl->fColor); |
| 701 | SkASSERT(sr && kBlack_Color == sr->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 702 | p->fColor = kRed_Color; |
| 703 | s->fColor = kBlack_Color; |
| 704 | if (kLeft_Child == pc) { |
| 705 | rotateLeft(p); |
| 706 | s = sl; |
| 707 | } else { |
| 708 | rotateRight(p); |
| 709 | s = sr; |
| 710 | } |
| 711 | sl = s->fChildren[kLeft_Child]; |
| 712 | sr = s->fChildren[kRight_Child]; |
| 713 | } |
| 714 | // x and s are now both black. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 715 | SkASSERT(kBlack_Color == s->fColor); |
| 716 | SkASSERT(NULL == x || kBlack_Color == x->fColor); |
| 717 | SkASSERT(p == s->fParent); |
| 718 | SkASSERT(NULL == x || p == x->fParent); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 719 | |
| 720 | // when x is deleted its subtree will have reduced black-height. |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 721 | slRed = (sl && kRed_Color == sl->fColor); |
| 722 | srRed = (sr && kRed_Color == sr->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 723 | if (!slRed && !srRed) { |
| 724 | // if s can be made red that will balance out x's removal |
| 725 | // to make both subtrees of p have the same black-height. |
| 726 | if (kBlack_Color == p->fColor) { |
| 727 | s->fColor = kRed_Color; |
| 728 | // now subtree at p has black-height of one less than |
| 729 | // p's parent's other child's subtree. We move x up to |
| 730 | // p and go through the loop again. At the top of loop |
| 731 | // we assumed x and x's children are black, which holds |
| 732 | // by above ifs. |
| 733 | // if p is the root there is no other subtree to balance |
| 734 | // against. |
| 735 | x = p; |
| 736 | p = x->fParent; |
| 737 | if (NULL == p) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 738 | SkASSERT(fRoot == x); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 739 | validate(); |
| 740 | return; |
| 741 | } else { |
| 742 | pc = p->fChildren[kLeft_Child] == x ? kLeft_Child : |
| 743 | kRight_Child; |
| 744 | |
| 745 | } |
| 746 | s = p->fChildren[1-pc]; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 747 | SkASSERT(s); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 748 | SkASSERT(p == s->fParent); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 749 | continue; |
| 750 | } else if (kRed_Color == p->fColor) { |
| 751 | // we can make p black and s red. This balance out p's |
| 752 | // two subtrees and keep the same black-height as it was |
| 753 | // before the delete. |
| 754 | s->fColor = kRed_Color; |
| 755 | p->fColor = kBlack_Color; |
| 756 | validate(); |
| 757 | return; |
| 758 | } |
| 759 | } |
| 760 | break; |
| 761 | } while (true); |
| 762 | // if we made it here one or both of sl and sr is red. |
| 763 | // s and x are black. We make sure that a red child is on |
| 764 | // the same side of s as s is of p. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 765 | SkASSERT(slRed || srRed); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 766 | if (kLeft_Child == pc && !srRed) { |
| 767 | s->fColor = kRed_Color; |
| 768 | sl->fColor = kBlack_Color; |
| 769 | rotateRight(s); |
| 770 | sr = s; |
| 771 | s = sl; |
| 772 | //sl = s->fChildren[kLeft_Child]; don't need this |
| 773 | } else if (kRight_Child == pc && !slRed) { |
| 774 | s->fColor = kRed_Color; |
| 775 | sr->fColor = kBlack_Color; |
| 776 | rotateLeft(s); |
| 777 | sl = s; |
| 778 | s = sr; |
| 779 | //sr = s->fChildren[kRight_Child]; don't need this |
| 780 | } |
| 781 | // now p is either red or black, x and s are red and s's 1-pc |
| 782 | // child is red. |
| 783 | // We rotate p towards x, pulling s up to replace p. We make |
| 784 | // p be black and s takes p's old color. |
| 785 | // Whether p was red or black, we've increased its pc subtree |
| 786 | // rooted at x by 1 (balancing the imbalance at the start) and |
| 787 | // we've also its subtree rooted at s's black-height by 1. This |
| 788 | // can be balanced by making s's red child be black. |
| 789 | s->fColor = p->fColor; |
| 790 | p->fColor = kBlack_Color; |
| 791 | if (kLeft_Child == pc) { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 792 | SkASSERT(sr && kRed_Color == sr->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 793 | sr->fColor = kBlack_Color; |
| 794 | rotateLeft(p); |
| 795 | } else { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 796 | SkASSERT(sl && kRed_Color == sl->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 797 | sl->fColor = kBlack_Color; |
| 798 | rotateRight(p); |
| 799 | } |
| 800 | } |
| 801 | else { |
| 802 | // x has exactly one implicit black child. x cannot be red. |
| 803 | // Proof by contradiction: Assume X is red. Let c0 be x's implicit |
| 804 | // child and c1 be its non-implicit child. c1 must be black because |
| 805 | // red nodes always have two black children. Then the two subtrees |
| 806 | // of x rooted at c0 and c1 will have different black-heights. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 807 | SkASSERT(kBlack_Color == x->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 808 | // So we know x is black and has one implicit black child, c0. c1 |
| 809 | // must be red, otherwise the subtree at c1 will have a different |
| 810 | // black-height than the subtree rooted at c0. |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 811 | SkASSERT(kRed_Color == x->fChildren[c]->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 812 | // replace x with c1, making c1 black, preserves all red-black tree |
| 813 | // props. |
| 814 | Node* c1 = x->fChildren[c]; |
| 815 | if (x == fFirst) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 816 | SkASSERT(c == kRight_Child); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 817 | fFirst = c1; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 818 | while (fFirst->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 819 | fFirst = fFirst->fChildren[kLeft_Child]; |
| 820 | } |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 821 | SkASSERT(fFirst == SuccessorNode(x)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 822 | } else if (x == fLast) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 823 | SkASSERT(c == kLeft_Child); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 824 | fLast = c1; |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 825 | while (fLast->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 826 | fLast = fLast->fChildren[kRight_Child]; |
| 827 | } |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 828 | SkASSERT(fLast == PredecessorNode(x)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 829 | } |
| 830 | c1->fParent = p; |
| 831 | p->fChildren[pc] = c1; |
| 832 | c1->fColor = kBlack_Color; |
| 833 | delete x; |
| 834 | validate(); |
| 835 | } |
| 836 | validate(); |
| 837 | } |
| 838 | |
| 839 | template <typename T, typename C> |
| 840 | void GrRedBlackTree<T,C>::RecursiveDelete(Node* x) { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 841 | if (x) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 842 | RecursiveDelete(x->fChildren[kLeft_Child]); |
| 843 | RecursiveDelete(x->fChildren[kRight_Child]); |
| 844 | delete x; |
| 845 | } |
| 846 | } |
| 847 | |
commit-bot@chromium.org | 515dcd3 | 2013-08-28 14:17:03 +0000 | [diff] [blame] | 848 | #ifdef SK_DEBUG |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 849 | template <typename T, typename C> |
| 850 | void GrRedBlackTree<T,C>::validate() const { |
| 851 | if (fCount) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 852 | SkASSERT(NULL == fRoot->fParent); |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 853 | SkASSERT(fFirst); |
| 854 | SkASSERT(fLast); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 855 | |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 856 | SkASSERT(kBlack_Color == fRoot->fColor); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 857 | if (1 == fCount) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 858 | SkASSERT(fFirst == fRoot); |
| 859 | SkASSERT(fLast == fRoot); |
| 860 | SkASSERT(0 == fRoot->fChildren[kLeft_Child]); |
| 861 | SkASSERT(0 == fRoot->fChildren[kRight_Child]); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 862 | } |
| 863 | } else { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 864 | SkASSERT(NULL == fRoot); |
| 865 | SkASSERT(NULL == fFirst); |
| 866 | SkASSERT(NULL == fLast); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 867 | } |
| 868 | #if DEEP_VALIDATE |
| 869 | int bh; |
| 870 | int count = checkNode(fRoot, &bh); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 871 | SkASSERT(count == fCount); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 872 | #endif |
| 873 | } |
| 874 | |
| 875 | template <typename T, typename C> |
| 876 | int GrRedBlackTree<T,C>::checkNode(Node* n, int* bh) const { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 877 | if (n) { |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 878 | SkASSERT(validateChildRelations(n, false)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 879 | if (kBlack_Color == n->fColor) { |
| 880 | *bh += 1; |
| 881 | } |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 882 | SkASSERT(!fComp(n->fItem, fFirst->fItem)); |
| 883 | SkASSERT(!fComp(fLast->fItem, n->fItem)); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 884 | int leftBh = *bh; |
| 885 | int rightBh = *bh; |
| 886 | int cl = checkNode(n->fChildren[kLeft_Child], &leftBh); |
| 887 | int cr = checkNode(n->fChildren[kRight_Child], &rightBh); |
tfarina@chromium.org | f6de475 | 2013-08-17 00:02:59 +0000 | [diff] [blame] | 888 | SkASSERT(leftBh == rightBh); |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 889 | *bh = leftBh; |
| 890 | return 1 + cl + cr; |
| 891 | } |
| 892 | return 0; |
| 893 | } |
| 894 | |
| 895 | template <typename T, typename C> |
| 896 | bool GrRedBlackTree<T,C>::validateChildRelations(const Node* n, |
| 897 | bool allowRedRed) const { |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 898 | if (n) { |
| 899 | if (n->fChildren[kLeft_Child] || |
| 900 | n->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 901 | if (n->fChildren[kLeft_Child] == n->fChildren[kRight_Child]) { |
| 902 | return validateChildRelationsFailed(); |
| 903 | } |
| 904 | if (n->fChildren[kLeft_Child] == n->fParent && |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 905 | n->fParent) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 906 | return validateChildRelationsFailed(); |
| 907 | } |
| 908 | if (n->fChildren[kRight_Child] == n->fParent && |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 909 | n->fParent) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 910 | return validateChildRelationsFailed(); |
| 911 | } |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 912 | if (n->fChildren[kLeft_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 913 | if (!allowRedRed && |
| 914 | kRed_Color == n->fChildren[kLeft_Child]->fColor && |
| 915 | kRed_Color == n->fColor) { |
| 916 | return validateChildRelationsFailed(); |
| 917 | } |
| 918 | if (n->fChildren[kLeft_Child]->fParent != n) { |
| 919 | return validateChildRelationsFailed(); |
| 920 | } |
| 921 | if (!(fComp(n->fChildren[kLeft_Child]->fItem, n->fItem) || |
| 922 | (!fComp(n->fChildren[kLeft_Child]->fItem, n->fItem) && |
| 923 | !fComp(n->fItem, n->fChildren[kLeft_Child]->fItem)))) { |
| 924 | return validateChildRelationsFailed(); |
| 925 | } |
| 926 | } |
bsalomon | 49f085d | 2014-09-05 13:34:00 -0700 | [diff] [blame] | 927 | if (n->fChildren[kRight_Child]) { |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 928 | if (!allowRedRed && |
| 929 | kRed_Color == n->fChildren[kRight_Child]->fColor && |
| 930 | kRed_Color == n->fColor) { |
| 931 | return validateChildRelationsFailed(); |
| 932 | } |
| 933 | if (n->fChildren[kRight_Child]->fParent != n) { |
| 934 | return validateChildRelationsFailed(); |
| 935 | } |
| 936 | if (!(fComp(n->fItem, n->fChildren[kRight_Child]->fItem) || |
| 937 | (!fComp(n->fChildren[kRight_Child]->fItem, n->fItem) && |
| 938 | !fComp(n->fItem, n->fChildren[kRight_Child]->fItem)))) { |
| 939 | return validateChildRelationsFailed(); |
| 940 | } |
| 941 | } |
| 942 | } |
| 943 | } |
| 944 | return true; |
| 945 | } |
| 946 | #endif |
| 947 | |
bsalomon@google.com | 6034c50 | 2011-02-22 16:37:47 +0000 | [diff] [blame] | 948 | #endif |