glib/gtree.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /*
  28  * MT safe
  29  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include <config.h>
  33 #endif
  34
  35 #include "glib.h"
  36
  37
  38 typedef struct _GTreeNode  GTreeNode;
  39
  40 struct _GTree
  41 {
  42   GTreeNode *root;
  43   GCompareDataFunc key_compare;
  44   GDestroyNotify   key_destroy_func;
  45   GDestroyNotify   value_destroy_func;
  46   gpointer         key_compare_data;
  47 };
  48
  49 struct _GTreeNode
  50 {
  51   gint balance;      /* height (left) - height (right) */
  52   GTreeNode *left;   /* left subtree */
  53   GTreeNode *right;  /* right subtree */
  54   gpointer key;      /* key for this node */
  55   gpointer value;    /* value stored at this node */
  56 };
  57
  58
  59 static GTreeNode* g_tree_node_new                   (gpointer          key,
  60                                                      gpointer          value);
  61 static void       g_tree_node_destroy               (GTreeNode        *node,
  62                                                      GDestroyNotify    key_destroy_func,
  63                                                      GDestroyNotify    value_destroy_func);
  64 static GTreeNode* g_tree_node_insert                (GTree            *tree,
  65                                                      GTreeNode        *node,
  66                                                      gpointer          key,
  67                                                      gpointer          value,
  68                                                      gboolean          replace,
  69                                                      gboolean         *inserted);
  70 static GTreeNode* g_tree_node_remove                (GTree            *tree,
  71                                                      GTreeNode        *node,
  72                                                      gconstpointer     key,
  73                                                      gboolean          notify);
  74 static GTreeNode* g_tree_node_balance               (GTreeNode        *node);
  75 static GTreeNode* g_tree_node_remove_leftmost       (GTreeNode        *node,
  76                                                      GTreeNode       **leftmost);
  77 static GTreeNode* g_tree_node_restore_left_balance  (GTreeNode        *node,
  78                                                      gint              old_balance);
  79 static GTreeNode* g_tree_node_restore_right_balance (GTreeNode        *node,
  80                                                      gint              old_balance);
  81 static GTreeNode* g_tree_node_lookup                (GTreeNode        *node,
  82                                                      GCompareDataFunc  compare,
  83                                                      gpointer          comp_data,
  84                                                      gconstpointer     key);
  85 static gint       g_tree_node_count                 (GTreeNode        *node);
  86 static gint       g_tree_node_pre_order             (GTreeNode        *node,
  87                                                      GTraverseFunc     traverse_func,
  88                                                      gpointer          data);
  89 static gint       g_tree_node_in_order              (GTreeNode        *node,
  90                                                      GTraverseFunc     traverse_func,
  91                                                      gpointer          data);
  92 static gint       g_tree_node_post_order            (GTreeNode        *node,
  93                                                      GTraverseFunc     traverse_func,
  94                                                      gpointer          data);
  95 static gpointer   g_tree_node_search                (GTreeNode        *node,
  96                                                      GCompareFunc      search_func,
  97                                                      gconstpointer     data);
  98 static gint       g_tree_node_height                (GTreeNode        *node);
  99 static GTreeNode* g_tree_node_rotate_left           (GTreeNode        *node);
 100 static GTreeNode* g_tree_node_rotate_right          (GTreeNode        *node);
 101 static void       g_tree_node_check                 (GTreeNode        *node);
 102
 103
 104 G_LOCK_DEFINE_STATIC (g_tree_global);
 105 static GMemChunk *node_mem_chunk = NULL;
 106 static GTreeNode *node_free_list = NULL;
 107
 108
 109 static GTreeNode*
 110 g_tree_node_new (gpointer key,
 111                  gpointer value)
 112 {
 113   GTreeNode *node;
 114
 115   G_LOCK (g_tree_global);
 116   if (node_free_list)
 117     {
 118       node = node_free_list;
 119       node_free_list = node->right;
 120     }
 121   else
 122     {
 123       if (!node_mem_chunk)
 124         node_mem_chunk = g_mem_chunk_new ("GLib GTreeNode mem chunk",
 125                                           sizeof (GTreeNode),
 126                                           1024,
 127                                           G_ALLOC_ONLY);
 128
 129       node = g_chunk_new (GTreeNode, node_mem_chunk);
 130    }
 131   G_UNLOCK (g_tree_global);
 132
 133   node->balance = 0;
 134   node->left = NULL;
 135   node->right = NULL;
 136   node->key = key;
 137   node->value = value;
 138
 139   return node;
 140 }
 141
 142 static void
 143 g_tree_node_destroy (GTreeNode      *node,
 144                      GDestroyNotify  key_destroy_func,
 145                      GDestroyNotify  value_destroy_func)
 146 {
 147   if (node)
 148     {
 149       g_tree_node_destroy (node->right,
 150                            key_destroy_func, value_destroy_func);
 151       g_tree_node_destroy (node->left,
 152                            key_destroy_func, value_destroy_func);
 153
 154       if (key_destroy_func)
 155         key_destroy_func (node->key);
 156       if (value_destroy_func)
 157         value_destroy_func (node->value);
 158
 159 #ifdef ENABLE_GC_FRIENDLY
 160       node->left = NULL;
 161       node->key = NULL;
 162       node->value = NULL;
 163 #endif /* ENABLE_GC_FRIENDLY */
 164
 165       G_LOCK (g_tree_global);
 166       node->right = node_free_list;
 167       node_free_list = node;
 168       G_UNLOCK (g_tree_global);
 169    }
 170 }
 171
 172 /**
 173  * g_tree_new:
 174  * @key_compare_func: the function used to order the nodes in the #GTree.
 175  *   It should return values similar to the standard
 176  *   <function>strcmp()</function> function -
 177  *   0 if the two arguments are equal, a negative value if the first argument
 178  *   comes before the second, or a positive value if the first argument comes
 179  *   after the second.
 180  *
 181  * Creates a new #GTree.
 182  *
 183  * Return value: a new #GTree.
 184  **/
 185 GTree*
 186 g_tree_new (GCompareFunc key_compare_func)
 187 {
 188   g_return_val_if_fail (key_compare_func != NULL, NULL);
 189
 190   return g_tree_new_full ((GCompareDataFunc) key_compare_func, NULL,
 191                           NULL, NULL);
 192 }
 193
 194 /**
 195  * g_tree_new_with_data:
 196  * @key_compare_func: qsort()-style comparison function.
 197  * @key_compare_data: data to pass to comparison function.
 198  *
 199  * Creates a new #GTree with a comparison function that accepts user data.
 200  * See g_tree_new() for more details.
 201  *
 202  * Return value: a new #GTree.
 203  **/
 204 GTree*
 205 g_tree_new_with_data (GCompareDataFunc key_compare_func,
 206                       gpointer         key_compare_data)
 207 {
 208   g_return_val_if_fail (key_compare_func != NULL, NULL);
 209
 210   return g_tree_new_full (key_compare_func, key_compare_data,
 211                           NULL, NULL);
 212 }
 213
 214 /**
 215  * g_tree_new_full:
 216  * @key_compare_func: qsort()-style comparison function.
 217  * @key_compare_data: data to pass to comparison function.
 218  * @key_destroy_func: a function to free the memory allocated for the key
 219  *   used when removing the entry from the #GTree or #NULL if you don't
 220  *   want to supply such a function.
 221  * @value_destroy_func: a function to free the memory allocated for the
 222  *   value used when removing the entry from the #GTree or #NULL if you
 223  *   don't want to supply such a function.
 224  *
 225  * Creates a new #GTree like g_tree_new() and allows to specify functions
 226  * to free the memory allocated for the key and value that get called when
 227  * removing the entry from the #GTree.
 228  *
 229  * Return value: a new #GTree.
 230  **/
 231 GTree*
 232 g_tree_new_full (GCompareDataFunc key_compare_func,
 233                  gpointer         key_compare_data,
 234                  GDestroyNotify   key_destroy_func,
 235                  GDestroyNotify   value_destroy_func)
 236 {
 237   GTree *tree;
 238
 239   g_return_val_if_fail (key_compare_func != NULL, NULL);
 240
 241   tree = g_new (GTree, 1);
 242   tree->root               = NULL;
 243   tree->key_compare        = key_compare_func;
 244   tree->key_destroy_func   = key_destroy_func;
 245   tree->value_destroy_func = value_destroy_func;
 246   tree->key_compare_data   = key_compare_data;
 247
 248   return tree;
 249 }
 250
 251 /**
 252  * g_tree_destroy:
 253  * @tree: a #GTree.
 254  *
 255  * Destroys the #GTree. If keys and/or values are dynamically allocated, you
 256  * should either free them first or create the #GTree using g_tree_new_full().
 257  * In the latter case the destroy functions you supplied will be called on
 258  * all keys and values before destroying the #GTree.
 259  **/
 260 void
 261 g_tree_destroy (GTree *tree)
 262 {
 263   g_return_if_fail (tree != NULL);
 264
 265   g_tree_node_destroy (tree->root,
 266                        tree->key_destroy_func,
 267                        tree->value_destroy_func);
 268
 269   g_free (tree);
 270 }
 271
 272 /**
 273  * g_tree_insert:
 274  * @tree: a #Gtree.
 275  * @key: the key to insert.
 276  * @value: the value corresponding to the key.
 277  *
 278  * Inserts a key/value pair into a #GTree. If the given key already exists
 279  * in the #GTree its corresponding value is set to the new value. If you
 280  * supplied a value_destroy_func when creating the #GTree, the old value is
 281  * freed using that function. If you supplied a key_destroy_func when
 282  * creating the #GTree, the passed key is freed using that function.
 283  *
 284  * The tree is automatically 'balanced' as new key/value pairs are added,
 285  * so that the distance from the root to every leaf is as small as possible.
 286  **/
 287 void
 288 g_tree_insert (GTree    *tree,
 289                gpointer  key,
 290                gpointer  value)
 291 {
 292   gboolean   inserted;
 293
 294   g_return_if_fail (tree != NULL);
 295
 296   inserted = FALSE;
 297   tree->root = g_tree_node_insert (tree,
 298                                    tree->root,
 299                                    key, value,
 300                                    FALSE, &inserted);
 301 }
 302
 303 /**
 304  * g_tree_replace:
 305  * @tree: a #Gtree.
 306  * @key: the key to insert.
 307  * @value: the value corresponding to the key.
 308  *
 309  * Inserts a new key and value into a #GTree similar to g_tree_insert().
 310  * The difference is that if the key already exists in the #GTree, it gets
 311  * replaced by the new key. If you supplied a value_destroy_func when
 312  * creating the #GTree, the old value is freed using that function. If you
 313  * supplied a key_destroy_func when creating the #GTree, the old key is
 314  * freed using that function.
 315  *
 316  * The tree is automatically 'balanced' as new key/value pairs are added,
 317  * so that the distance from the root to every leaf is as small as possible.
 318  **/
 319 void
 320 g_tree_replace (GTree    *tree,
 321                 gpointer  key,
 322                 gpointer  value)
 323 {
 324   gboolean   inserted;
 325
 326   g_return_if_fail (tree != NULL);
 327
 328   inserted = FALSE;
 329   tree->root = g_tree_node_insert (tree,
 330                                    tree->root,
 331                                    key, value,
 332                                    TRUE, &inserted);
 333 }
 334
 335 /**
 336  * g_tree_remove:
 337  * @tree: a #Gtree.
 338  * @key: the key to remove.
 339  *
 340  * Removes a key/value pair from a #GTree.
 341  *
 342  * If the #GTree was created using g_tree_new_full(), the key and value
 343  * are freed using the supplied destroy_functions, otherwise you have to
 344  * make sure that any dynamically allocated values are freed yourself.
 345  **/
 346 void
 347 g_tree_remove (GTree         *tree,
 348                gconstpointer  key)
 349 {
 350   g_return_if_fail (tree != NULL);
 351
 352   tree->root = g_tree_node_remove (tree, tree->root, key, TRUE);
 353 }
 354
 355 /**
 356  * g_tree_steal:
 357  * @tree: a #Gtree.
 358  * @key: the key to remove.
 359  *
 360  * Removes a key and its associated value from a #GTree without calling
 361  * the key and value destroy functions.
 362  **/
 363 void
 364 g_tree_steal (GTree         *tree,
 365               gconstpointer  key)
 366 {
 367   g_return_if_fail (tree != NULL);
 368
 369   tree->root = g_tree_node_remove (tree, tree->root, key, FALSE);
 370 }
 371
 372 /**
 373  * g_tree_lookup:
 374  * @tree: a #GTree.
 375  * @key: the key to look up.
 376  *
 377  * Gets the value corresponding to the given key. Since a #GTree is
 378  * automatically balanced as key/value pairs are added, key lookup is very
 379  * fast.
 380  *
 381  * Return value: the value corresponding to the key.
 382  **/
 383 gpointer
 384 g_tree_lookup (GTree         *tree,
 385                gconstpointer  key)
 386 {
 387   GTreeNode *node;
 388
 389   g_return_val_if_fail (tree != NULL, NULL);
 390
 391   node = g_tree_node_lookup (tree->root,
 392                              tree->key_compare, tree->key_compare_data, key);
 393
 394   return node ? node->value : NULL;
 395 }
 396
 397 /**
 398  * g_tree_lookup_extended:
 399  * @tree: a #GTree.
 400  * @lookup_key: the key to look up.
 401  * @orig_key: returns the original key.
 402  * @value: returns the value associated with the key.
 403  *
 404  * Looks up a key in the #GTree, returning the original key and the
 405  * associated value and a gboolean which is TRUE if the key was found. This
 406  * is useful if you need to free the memory allocated for the original key,
 407  * for example before calling g_tree_remove().
 408  *
 409  * Return value: #TRUE if the key was found in the #GTree.
 410  **/
 411 gboolean
 412 g_tree_lookup_extended (GTree         *tree,
 413                         gconstpointer  lookup_key,
 414                         gpointer      *orig_key,
 415                         gpointer      *value)
 416 {
 417   GTreeNode *node;
 418
 419   g_return_val_if_fail (tree != NULL, FALSE);
 420
 421   node = g_tree_node_lookup (tree->root,
 422                              tree->key_compare, tree->key_compare_data, lookup_key);
 423
 424   if (node)
 425     {
 426       if (orig_key)
 427         *orig_key = node->key;
 428       if (value)
 429         *value = node->value;
 430       return TRUE;
 431     }
 432   else
 433     return FALSE;
 434 }
 435
 436 /**
 437  * g_tree_foreach:
 438  * @tree: a #GTree.
 439  * @func: the function to call for each node visited. If this function
 440  *   returns TRUE, the traversal is stopped.
 441  * @user_data: user data to pass to the function.
 442  *
 443  * Calls the given function for each of the key/value pairs in the #GTree.
 444  * The function is passed the key and value of each pair, and the given
 445  * @data parameter.
 446  **/
 447 void
 448 g_tree_foreach (GTree         *tree,
 449                 GTraverseFunc  func,
 450                 gpointer       user_data)
 451 {
 452   g_return_if_fail (tree != NULL);
 453
 454   if (!tree->root)
 455     return;
 456
 457   g_tree_node_in_order (tree->root, func, user_data);
 458 }
 459
 460 /**
 461  * g_tree_traverse:
 462  * @tree: a #GTree.
 463  * @traverse_func: the function to call for each node visited. If this
 464  *   function returns TRUE, the traversal is stopped.
 465  * @traverse_type: the order in which nodes are visited, one of %G_IN_ORDER,
 466  *   %G_PRE_ORDER and %G_POST_ORDER.
 467  * @user_data: user data to pass to the function.
 468  *
 469  * Calls the given function for each node in the GTree. This function is
 470  * deprecated, use g_tree_foreach() instead.
 471  **/
 472 void
 473 g_tree_traverse (GTree         *tree,
 474                  GTraverseFunc  traverse_func,
 475                  GTraverseType  traverse_type,
 476                  gpointer       user_data)
 477 {
 478   g_return_if_fail (tree != NULL);
 479
 480   if (!tree->root)
 481     return;
 482
 483   switch (traverse_type)
 484     {
 485     case G_PRE_ORDER:
 486       g_tree_node_pre_order (tree->root, traverse_func, user_data);
 487       break;
 488
 489     case G_IN_ORDER:
 490       g_tree_node_in_order (tree->root, traverse_func, user_data);
 491       break;
 492
 493     case G_POST_ORDER:
 494       g_tree_node_post_order (tree->root, traverse_func, user_data);
 495       break;
 496
 497     case G_LEVEL_ORDER:
 498       g_warning ("g_tree_traverse(): traverse type G_LEVEL_ORDER isn't implemented.");
 499       break;
 500     }
 501 }
 502
 503 /**
 504  * g_tree_search:
 505  * @tree: a #GTree.
 506  * @search_func: the comparison function used to search the #GTree.
 507  * @user_data: the data passed as the second argument to the @search_func
 508  * function.
 509  *
 510  * Searches a #GTree using an alternative form of the comparison function.
 511  *
 512  * This function is not as useful as it sounds.
 513  * It allows you to use a different function for performing the lookup of
 514  * a key. However, since the tree is ordered according to the @key_compare_func
 515  * function passed to g_tree_new(), the function you pass to g_tree_search()
 516  * must return exactly the same value as would be returned by the comparison
 517  * function, for each pair of tree nodes, or the search will not work.
 518  *
 519  * To search for a specific value, you can use g_tree_foreach() or
 520  * g_tree_traverse().
 521  *
 522  * Return value: the value corresponding to the found key, or NULL if the key
 523  * is not found.
 524  **/
 525 gpointer
 526 g_tree_search (GTree         *tree,
 527                GCompareFunc   search_func,
 528                gconstpointer  user_data)
 529 {
 530   g_return_val_if_fail (tree != NULL, NULL);
 531
 532   if (tree->root)
 533     return g_tree_node_search (tree->root, search_func, user_data);
 534   else
 535     return NULL;
 536 }
 537
 538 /**
 539  * g_tree_height:
 540  * @tree: a #GTree.
 541  *
 542  * Gets the height of a #GTree.
 543  *
 544  * If the #GTree contains no nodes, the height is 0.
 545  * If the #GTree contains only one root node the height is 1.
 546  * If the root node has children the height is 2, etc.
 547  *
 548  * Return value: the height of the #GTree.
 549  **/
 550 gint
 551 g_tree_height (GTree *tree)
 552 {
 553   g_return_val_if_fail (tree != NULL, 0);
 554
 555   if (tree->root)
 556     return g_tree_node_height (tree->root);
 557   else
 558     return 0;
 559 }
 560
 561 /**
 562  * g_tree_nnodes:
 563  * @tree: a #GTree.
 564  *
 565  * Gets the number of nodes in a #GTree.
 566  *
 567  * Return value: the number of nodes in the #GTree.
 568  **/
 569 gint
 570 g_tree_nnodes (GTree *tree)
 571 {
 572   g_return_val_if_fail (tree != NULL, 0);
 573
 574   if (tree->root)
 575     return g_tree_node_count (tree->root);
 576   else
 577     return 0;
 578 }
 579
 580 static GTreeNode*
 581 g_tree_node_insert (GTree     *tree,
 582                     GTreeNode *node,
 583                     gpointer   key,
 584                     gpointer   value,
 585                     gboolean   replace,
 586                     gboolean  *inserted)
 587 {
 588   gint  old_balance;
 589   gint  cmp;
 590
 591   if (!node)
 592     {
 593       *inserted = TRUE;
 594       return g_tree_node_new (key, value);
 595     }
 596
 597   cmp = tree->key_compare (key, node->key, tree->key_compare_data);
 598   if (cmp == 0)
 599     {
 600       *inserted = FALSE;
 601
 602       if (tree->value_destroy_func)
 603         tree->value_destroy_func (node->value);
 604
 605       node->value = value;
 606
 607       if (replace)
 608         {
 609           if (tree->key_destroy_func)
 610             tree->key_destroy_func (node->key);
 611
 612           node->key = key;
 613         }
 614       else
 615         {
 616           /* free the passed key */
 617           if (tree->key_destroy_func)
 618             tree->key_destroy_func (key);
 619         }
 620
 621       return node;
 622     }
 623
 624   if (cmp < 0)
 625     {
 626       if (node->left)
 627         {
 628           old_balance = node->left->balance;
 629           node->left = g_tree_node_insert (tree,
 630                                            node->left,
 631                                            key, value,
 632                                            replace, inserted);
 633
 634           if ((old_balance != node->left->balance) && node->left->balance)
 635             node->balance -= 1;
 636         }
 637       else
 638         {
 639           *inserted = TRUE;
 640           node->left = g_tree_node_new (key, value);
 641           node->balance -= 1;
 642         }
 643     }
 644   else if (cmp > 0)
 645     {
 646       if (node->right)
 647         {
 648           old_balance = node->right->balance;
 649           node->right = g_tree_node_insert (tree,
 650                                             node->right,
 651                                             key, value,
 652                                             replace, inserted);
 653
 654           if ((old_balance != node->right->balance) && node->right->balance)
 655             node->balance += 1;
 656         }
 657       else
 658         {
 659           *inserted = TRUE;
 660           node->right = g_tree_node_new (key, value);
 661           node->balance += 1;
 662         }
 663     }
 664
 665   if (*inserted)
 666     {
 667       if ((node->balance < -1) || (node->balance > 1))
 668         node = g_tree_node_balance (node);
 669     }
 670
 671   return node;
 672 }
 673
 674 static GTreeNode*
 675 g_tree_node_remove (GTree         *tree,
 676                     GTreeNode     *node,
 677                     gconstpointer  key,
 678                     gboolean       notify)
 679 {
 680   GTreeNode *new_root;
 681   gint old_balance;
 682   gint cmp;
 683
 684   if (!node)
 685     return NULL;
 686
 687   cmp = tree->key_compare (key, node->key, tree->key_compare_data);
 688   if (cmp == 0)
 689     {
 690       GTreeNode *garbage;
 691
 692       garbage = node;
 693
 694       if (!node->right)
 695         {
 696           node = node->left;
 697         }
 698       else
 699         {
 700           old_balance = node->right->balance;
 701           node->right = g_tree_node_remove_leftmost (node->right, &new_root);
 702           new_root->left = node->left;
 703           new_root->right = node->right;
 704           new_root->balance = node->balance;
 705           node = g_tree_node_restore_right_balance (new_root, old_balance);
 706         }
 707
 708       if (notify)
 709         {
 710           if (tree->key_destroy_func)
 711             tree->key_destroy_func (garbage->key);
 712           if (tree->value_destroy_func)
 713             tree->value_destroy_func (garbage->value);
 714         }
 715
 716 #ifdef ENABLE_GC_FRIENDLY
 717       garbage->left = NULL;
 718       garbage->key = NULL;
 719       garbage->value = NULL;
 720 #endif /* ENABLE_GC_FRIENDLY */
 721
 722       G_LOCK (g_tree_global);
 723       garbage->right = node_free_list;
 724       node_free_list = garbage;
 725       G_UNLOCK (g_tree_global);
 726    }
 727   else if (cmp < 0)
 728     {
 729       if (node->left)
 730         {
 731           old_balance = node->left->balance;
 732           node->left = g_tree_node_remove (tree, node->left, key, notify);
 733           node = g_tree_node_restore_left_balance (node, old_balance);
 734         }
 735     }
 736   else if (cmp > 0)
 737     {
 738       if (node->right)
 739         {
 740           old_balance = node->right->balance;
 741           node->right = g_tree_node_remove (tree, node->right, key, notify);
 742           node = g_tree_node_restore_right_balance (node, old_balance);
 743         }
 744     }
 745
 746   return node;
 747 }
 748
 749 static GTreeNode*
 750 g_tree_node_balance (GTreeNode *node)
 751 {
 752   if (node->balance < -1)
 753     {
 754       if (node->left->balance > 0)
 755         node->left = g_tree_node_rotate_left (node->left);
 756       node = g_tree_node_rotate_right (node);
 757     }
 758   else if (node->balance > 1)
 759     {
 760       if (node->right->balance < 0)
 761         node->right = g_tree_node_rotate_right (node->right);
 762       node = g_tree_node_rotate_left (node);
 763     }
 764
 765   return node;
 766 }
 767
 768 static GTreeNode*
 769 g_tree_node_remove_leftmost (GTreeNode  *node,
 770                              GTreeNode **leftmost)
 771 {
 772   gint old_balance;
 773
 774   if (!node->left)
 775     {
 776       *leftmost = node;
 777       return node->right;
 778     }
 779
 780   old_balance = node->left->balance;
 781   node->left = g_tree_node_remove_leftmost (node->left, leftmost);
 782   return g_tree_node_restore_left_balance (node, old_balance);
 783 }
 784
 785 static GTreeNode*
 786 g_tree_node_restore_left_balance (GTreeNode *node,
 787                                   gint       old_balance)
 788 {
 789   if (!node->left)
 790     node->balance += 1;
 791   else if ((node->left->balance != old_balance) &&
 792            (node->left->balance == 0))
 793     node->balance += 1;
 794
 795   if (node->balance > 1)
 796     return g_tree_node_balance (node);
 797   return node;
 798 }
 799
 800 static GTreeNode*
 801 g_tree_node_restore_right_balance (GTreeNode *node,
 802                                    gint       old_balance)
 803 {
 804   if (!node->right)
 805     node->balance -= 1;
 806   else if ((node->right->balance != old_balance) &&
 807            (node->right->balance == 0))
 808     node->balance -= 1;
 809
 810   if (node->balance < -1)
 811     return g_tree_node_balance (node);
 812   return node;
 813 }
 814
 815 static GTreeNode *
 816 g_tree_node_lookup (GTreeNode        *node,
 817                     GCompareDataFunc  compare,
 818                     gpointer          compare_data,
 819                     gconstpointer     key)
 820 {
 821   gint cmp;
 822
 823   if (!node)
 824     return NULL;
 825
 826   cmp = (* compare) (key, node->key, compare_data);
 827   if (cmp == 0)
 828     return node;
 829
 830   if (cmp < 0)
 831     {
 832       if (node->left)
 833         return g_tree_node_lookup (node->left, compare, compare_data, key);
 834     }
 835   else if (cmp > 0)
 836     {
 837       if (node->right)
 838         return g_tree_node_lookup (node->right, compare, compare_data, key);
 839     }
 840
 841   return NULL;
 842 }
 843
 844 static gint
 845 g_tree_node_count (GTreeNode *node)
 846 {
 847   gint count;
 848
 849   count = 1;
 850   if (node->left)
 851     count += g_tree_node_count (node->left);
 852   if (node->right)
 853     count += g_tree_node_count (node->right);
 854
 855   return count;
 856 }
 857
 858 static gint
 859 g_tree_node_pre_order (GTreeNode     *node,
 860                        GTraverseFunc  traverse_func,
 861                        gpointer       data)
 862 {
 863   if ((*traverse_func) (node->key, node->value, data))
 864     return TRUE;
 865   if (node->left)
 866     {
 867       if (g_tree_node_pre_order (node->left, traverse_func, data))
 868         return TRUE;
 869     }
 870   if (node->right)
 871     {
 872       if (g_tree_node_pre_order (node->right, traverse_func, data))
 873         return TRUE;
 874     }
 875
 876   return FALSE;
 877 }
 878
 879 static gint
 880 g_tree_node_in_order (GTreeNode     *node,
 881                       GTraverseFunc  traverse_func,
 882                       gpointer       data)
 883 {
 884   if (node->left)
 885     {
 886       if (g_tree_node_in_order (node->left, traverse_func, data))
 887         return TRUE;
 888     }
 889   if ((*traverse_func) (node->key, node->value, data))
 890     return TRUE;
 891   if (node->right)
 892     {
 893       if (g_tree_node_in_order (node->right, traverse_func, data))
 894         return TRUE;
 895     }
 896
 897   return FALSE;
 898 }
 899
 900 static gint
 901 g_tree_node_post_order (GTreeNode     *node,
 902                         GTraverseFunc  traverse_func,
 903                         gpointer       data)
 904 {
 905   if (node->left)
 906     {
 907       if (g_tree_node_post_order (node->left, traverse_func, data))
 908         return TRUE;
 909     }
 910   if (node->right)
 911     {
 912       if (g_tree_node_post_order (node->right, traverse_func, data))
 913         return TRUE;
 914     }
 915   if ((*traverse_func) (node->key, node->value, data))
 916     return TRUE;
 917
 918   return FALSE;
 919 }
 920
 921 static gpointer
 922 g_tree_node_search (GTreeNode     *node,
 923                     GCompareFunc   search_func,
 924                     gconstpointer  data)
 925 {
 926   gint dir;
 927
 928   if (!node)
 929     return NULL;
 930
 931   do {
 932     dir = (* search_func) (node->key, data);
 933     if (dir == 0)
 934       return node->value;
 935
 936     if (dir < 0)
 937       node = node->left;
 938     else if (dir > 0)
 939       node = node->right;
 940   } while (node);
 941
 942   return NULL;
 943 }
 944
 945 static gint
 946 g_tree_node_height (GTreeNode *node)
 947 {
 948   gint left_height;
 949   gint right_height;
 950
 951   if (node)
 952     {
 953       left_height = 0;
 954       right_height = 0;
 955
 956       if (node->left)
 957         left_height = g_tree_node_height (node->left);
 958
 959       if (node->right)
 960         right_height = g_tree_node_height (node->right);
 961
 962       return MAX (left_height, right_height) + 1;
 963     }
 964
 965   return 0;
 966 }
 967
 968 static GTreeNode*
 969 g_tree_node_rotate_left (GTreeNode *node)
 970 {
 971   GTreeNode *right;
 972   gint a_bal;
 973   gint b_bal;
 974
 975   right = node->right;
 976
 977   node->right = right->left;
 978   right->left = node;
 979
 980   a_bal = node->balance;
 981   b_bal = right->balance;
 982
 983   if (b_bal <= 0)
 984     {
 985       if (a_bal >= 1)
 986         right->balance = b_bal - 1;
 987       else
 988         right->balance = a_bal + b_bal - 2;
 989       node->balance = a_bal - 1;
 990     }
 991   else
 992     {
 993       if (a_bal <= b_bal)
 994         right->balance = a_bal - 2;
 995       else
 996         right->balance = b_bal - 1;
 997       node->balance = a_bal - b_bal - 1;
 998     }
 999
1000   return right;
1001 }
1002
1003 static GTreeNode*
1004 g_tree_node_rotate_right (GTreeNode *node)
1005 {
1006   GTreeNode *left;
1007   gint a_bal;
1008   gint b_bal;
1009
1010   left = node->left;
1011
1012   node->left = left->right;
1013   left->right = node;
1014
1015   a_bal = node->balance;
1016   b_bal = left->balance;
1017
1018   if (b_bal <= 0)
1019     {
1020       if (b_bal > a_bal)
1021         left->balance = b_bal + 1;
1022       else
1023         left->balance = a_bal + 2;
1024       node->balance = a_bal - b_bal + 1;
1025     }
1026   else
1027     {
1028       if (a_bal <= -1)
1029         left->balance = b_bal + 1;
1030       else
1031         left->balance = a_bal + b_bal + 2;
1032       node->balance = a_bal + 1;
1033     }
1034
1035   return left;
1036 }
1037
1038 static void
1039 g_tree_node_check (GTreeNode *node)
1040 {
1041   gint left_height;
1042   gint right_height;
1043   gint balance;
1044
1045   if (node)
1046     {
1047       left_height = 0;
1048       right_height = 0;
1049
1050       if (node->left)
1051         left_height = g_tree_node_height (node->left);
1052       if (node->right)
1053         right_height = g_tree_node_height (node->right);
1054
1055       balance = right_height - left_height;
1056       if (balance != node->balance)
1057         g_log (g_log_domain_glib, G_LOG_LEVEL_INFO,
1058                "g_tree_node_check: failed: %d ( %d )\n",
1059                balance, node->balance);
1060
1061       if (node->left)
1062         g_tree_node_check (node->left);
1063       if (node->right)
1064         g_tree_node_check (node->right);
1065     }
1066 }