glib/gnode.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * GNode: N-way tree implementation.
   5  * Copyright (C) 1998 Tim Janik
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /*
  22  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  23  * file for a list of people on the GLib Team.  See the ChangeLog
  24  * files for a list of changes.  These files are distributed with
  25  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  26  */
  27
  28 /*
  29  * MT safe
  30  */
  31
  32 #include "config.h"
  33
  34 #include "gnode.h"
  35
  36 #include "gslice.h"
  37
  38 #include "gtestutils.h"
  39
  40 /**
  41  * SECTION:trees-nary
  42  * @title: N-ary Trees
  43  * @short_description: trees of data with any number of branches
  44  *
  45  * The #GNode struct and its associated functions provide a N-ary tree
  46  * data structure, where nodes in the tree can contain arbitrary data.
  47  *
  48  * To create a new tree use g_node_new().
  49  *
  50  * To insert a node into a tree use g_node_insert(),
  51  * g_node_insert_before(), g_node_append() and g_node_prepend().
  52  *
  53  * To create a new node and insert it into a tree use
  54  * g_node_insert_data(), g_node_insert_data_after(),
  55  * g_node_insert_data_before(), g_node_append_data()
  56  * and g_node_prepend_data().
  57  *
  58  * To reverse the children of a node use g_node_reverse_children().
  59  *
  60  * To find a node use g_node_get_root(), g_node_find(),
  61  * g_node_find_child(), g_node_child_index(), g_node_child_position(),
  62  * g_node_first_child(), g_node_last_child(), g_node_nth_child(),
  63  * g_node_first_sibling(), g_node_prev_sibling(), g_node_next_sibling()
  64  * or g_node_last_sibling().
  65  *
  66  * To get information about a node or tree use G_NODE_IS_LEAF(),
  67  * G_NODE_IS_ROOT(), g_node_depth(), g_node_n_nodes(),
  68  * g_node_n_children(), g_node_is_ancestor() or g_node_max_height().
  69  *
  70  * To traverse a tree, calling a function for each node visited in the
  71  * traversal, use g_node_traverse() or g_node_children_foreach().
  72  *
  73  * To remove a node or subtree from a tree use g_node_unlink() or
  74  * g_node_destroy().
  75  **/
  76
  77 /**
  78  * GNode:
  79  * @data: contains the actual data of the node.
  80  * @next: points to the node's next sibling (a sibling is another
  81  *        #GNode with the same parent).
  82  * @prev: points to the node's previous sibling.
  83  * @parent: points to the parent of the #GNode, or is %NULL if the
  84  *          #GNode is the root of the tree.
  85  * @children: points to the first child of the #GNode.  The other
  86  *            children are accessed by using the @next pointer of each
  87  *            child.
  88  *
  89  * The #GNode struct represents one node in a [n-ary tree][glib-N-ary-Trees].
  90  **/
  91
  92 #define g_node_alloc0()         g_slice_new0 (GNode)
  93 #define g_node_free(node)       g_slice_free (GNode, node)
  94
  95 /* --- functions --- */
  96 /**
  97  * g_node_new:
  98  * @data: the data of the new node
  99  *
 100  * Creates a new #GNode containing the given data.
 101  * Used to create the first node in a tree.
 102  *
 103  * Returns: a new #GNode
 104  */
 105 GNode*
 106 g_node_new (gpointer data)
 107 {
 108   GNode *node = g_node_alloc0 ();
 109   node->data = data;
 110   return node;
 111 }
 112
 113 static void
 114 g_nodes_free (GNode *node)
 115 {
 116   while (node)
 117     {
 118       GNode *next = node->next;
 119       if (node->children)
 120         g_nodes_free (node->children);
 121       g_node_free (node);
 122       node = next;
 123     }
 124 }
 125
 126 /**
 127  * g_node_destroy:
 128  * @root: the root of the tree/subtree to destroy
 129  *
 130  * Removes @root and its children from the tree, freeing any memory
 131  * allocated.
 132  */
 133 void
 134 g_node_destroy (GNode *root)
 135 {
 136   g_return_if_fail (root != NULL);
 137
 138   if (!G_NODE_IS_ROOT (root))
 139     g_node_unlink (root);
 140
 141   g_nodes_free (root);
 142 }
 143
 144 /**
 145  * g_node_unlink:
 146  * @node: the #GNode to unlink, which becomes the root of a new tree
 147  *
 148  * Unlinks a #GNode from a tree, resulting in two separate trees.
 149  */
 150 void
 151 g_node_unlink (GNode *node)
 152 {
 153   g_return_if_fail (node != NULL);
 154
 155   if (node->prev)
 156     node->prev->next = node->next;
 157   else if (node->parent)
 158     node->parent->children = node->next;
 159   node->parent = NULL;
 160   if (node->next)
 161     {
 162       node->next->prev = node->prev;
 163       node->next = NULL;
 164     }
 165   node->prev = NULL;
 166 }
 167
 168 /**
 169  * g_node_copy_deep:
 170  * @node: a #GNode
 171  * @copy_func: the function which is called to copy the data inside each node,
 172  *   or %NULL to use the original data.
 173  * @data: data to pass to @copy_func
 174  *
 175  * Recursively copies a #GNode and its data.
 176  *
 177  * Returns: a new #GNode containing copies of the data in @node.
 178  *
 179  * Since: 2.4
 180  **/
 181 GNode*
 182 g_node_copy_deep (GNode     *node,
 183                   GCopyFunc  copy_func,
 184                   gpointer   data)
 185 {
 186   GNode *new_node = NULL;
 187
 188   if (copy_func == NULL)
 189         return g_node_copy (node);
 190
 191   if (node)
 192     {
 193       GNode *child, *new_child;
 194
 195       new_node = g_node_new (copy_func (node->data, data));
 196
 197       for (child = g_node_last_child (node); child; child = child->prev)
 198         {
 199           new_child = g_node_copy_deep (child, copy_func, data);
 200           g_node_prepend (new_node, new_child);
 201         }
 202     }
 203
 204   return new_node;
 205 }
 206
 207 /**
 208  * g_node_copy:
 209  * @node: a #GNode
 210  *
 211  * Recursively copies a #GNode (but does not deep-copy the data inside the
 212  * nodes, see g_node_copy_deep() if you need that).
 213  *
 214  * Returns: a new #GNode containing the same data pointers
 215  */
 216 GNode*
 217 g_node_copy (GNode *node)
 218 {
 219   GNode *new_node = NULL;
 220
 221   if (node)
 222     {
 223       GNode *child;
 224
 225       new_node = g_node_new (node->data);
 226
 227       for (child = g_node_last_child (node); child; child = child->prev)
 228         g_node_prepend (new_node, g_node_copy (child));
 229     }
 230
 231   return new_node;
 232 }
 233
 234 /**
 235  * g_node_insert:
 236  * @parent: the #GNode to place @node under
 237  * @position: the position to place @node at, with respect to its siblings
 238  *     If position is -1, @node is inserted as the last child of @parent
 239  * @node: the #GNode to insert
 240  *
 241  * Inserts a #GNode beneath the parent at the given position.
 242  *
 243  * Returns: the inserted #GNode
 244  */
 245 GNode*
 246 g_node_insert (GNode *parent,
 247                gint   position,
 248                GNode *node)
 249 {
 250   g_return_val_if_fail (parent != NULL, node);
 251   g_return_val_if_fail (node != NULL, node);
 252   g_return_val_if_fail (G_NODE_IS_ROOT (node), node);
 253
 254   if (position > 0)
 255     return g_node_insert_before (parent,
 256                                  g_node_nth_child (parent, position),
 257                                  node);
 258   else if (position == 0)
 259     return g_node_prepend (parent, node);
 260   else /* if (position < 0) */
 261     return g_node_append (parent, node);
 262 }
 263
 264 /**
 265  * g_node_insert_before:
 266  * @parent: the #GNode to place @node under
 267  * @sibling: the sibling #GNode to place @node before.
 268  *     If sibling is %NULL, the node is inserted as the last child of @parent.
 269  * @node: the #GNode to insert
 270  *
 271  * Inserts a #GNode beneath the parent before the given sibling.
 272  *
 273  * Returns: the inserted #GNode
 274  */
 275 GNode*
 276 g_node_insert_before (GNode *parent,
 277                       GNode *sibling,
 278                       GNode *node)
 279 {
 280   g_return_val_if_fail (parent != NULL, node);
 281   g_return_val_if_fail (node != NULL, node);
 282   g_return_val_if_fail (G_NODE_IS_ROOT (node), node);
 283   if (sibling)
 284     g_return_val_if_fail (sibling->parent == parent, node);
 285
 286   node->parent = parent;
 287
 288   if (sibling)
 289     {
 290       if (sibling->prev)
 291         {
 292           node->prev = sibling->prev;
 293           node->prev->next = node;
 294           node->next = sibling;
 295           sibling->prev = node;
 296         }
 297       else
 298         {
 299           node->parent->children = node;
 300           node->next = sibling;
 301           sibling->prev = node;
 302         }
 303     }
 304   else
 305     {
 306       if (parent->children)
 307         {
 308           sibling = parent->children;
 309           while (sibling->next)
 310             sibling = sibling->next;
 311           node->prev = sibling;
 312           sibling->next = node;
 313         }
 314       else
 315         node->parent->children = node;
 316     }
 317
 318   return node;
 319 }
 320
 321 /**
 322  * g_node_insert_after:
 323  * @parent: the #GNode to place @node under
 324  * @sibling: the sibling #GNode to place @node after.
 325  *     If sibling is %NULL, the node is inserted as the first child of @parent.
 326  * @node: the #GNode to insert
 327  *
 328  * Inserts a #GNode beneath the parent after the given sibling.
 329  *
 330  * Returns: the inserted #GNode
 331  */
 332 GNode*
 333 g_node_insert_after (GNode *parent,
 334                      GNode *sibling,
 335                      GNode *node)
 336 {
 337   g_return_val_if_fail (parent != NULL, node);
 338   g_return_val_if_fail (node != NULL, node);
 339   g_return_val_if_fail (G_NODE_IS_ROOT (node), node);
 340   if (sibling)
 341     g_return_val_if_fail (sibling->parent == parent, node);
 342
 343   node->parent = parent;
 344
 345   if (sibling)
 346     {
 347       if (sibling->next)
 348         {
 349           sibling->next->prev = node;
 350         }
 351       node->next = sibling->next;
 352       node->prev = sibling;
 353       sibling->next = node;
 354     }
 355   else
 356     {
 357       if (parent->children)
 358         {
 359           node->next = parent->children;
 360           parent->children->prev = node;
 361         }
 362       parent->children = node;
 363     }
 364
 365   return node;
 366 }
 367
 368 /**
 369  * g_node_prepend:
 370  * @parent: the #GNode to place the new #GNode under
 371  * @node: the #GNode to insert
 372  *
 373  * Inserts a #GNode as the first child of the given parent.
 374  *
 375  * Returns: the inserted #GNode
 376  */
 377 GNode*
 378 g_node_prepend (GNode *parent,
 379                 GNode *node)
 380 {
 381   g_return_val_if_fail (parent != NULL, node);
 382
 383   return g_node_insert_before (parent, parent->children, node);
 384 }
 385
 386 /**
 387  * g_node_get_root:
 388  * @node: a #GNode
 389  *
 390  * Gets the root of a tree.
 391  *
 392  * Returns: the root of the tree
 393  */
 394 GNode*
 395 g_node_get_root (GNode *node)
 396 {
 397   g_return_val_if_fail (node != NULL, NULL);
 398
 399   while (node->parent)
 400     node = node->parent;
 401
 402   return node;
 403 }
 404
 405 /**
 406  * g_node_is_ancestor:
 407  * @node: a #GNode
 408  * @descendant: a #GNode
 409  *
 410  * Returns %TRUE if @node is an ancestor of @descendant.
 411  * This is true if node is the parent of @descendant,
 412  * or if node is the grandparent of @descendant etc.
 413  *
 414  * Returns: %TRUE if @node is an ancestor of @descendant
 415  */
 416 gboolean
 417 g_node_is_ancestor (GNode *node,
 418                     GNode *descendant)
 419 {
 420   g_return_val_if_fail (node != NULL, FALSE);
 421   g_return_val_if_fail (descendant != NULL, FALSE);
 422
 423   while (descendant)
 424     {
 425       if (descendant->parent == node)
 426         return TRUE;
 427
 428       descendant = descendant->parent;
 429     }
 430
 431   return FALSE;
 432 }
 433
 434 /**
 435  * g_node_depth:
 436  * @node: a #GNode
 437  *
 438  * Gets the depth of a #GNode.
 439  *
 440  * If @node is %NULL the depth is 0. The root node has a depth of 1.
 441  * For the children of the root node the depth is 2. And so on.
 442  *
 443  * Returns: the depth of the #GNode
 444  */
 445 guint
 446 g_node_depth (GNode *node)
 447 {
 448   guint depth = 0;
 449
 450   while (node)
 451     {
 452       depth++;
 453       node = node->parent;
 454     }
 455
 456   return depth;
 457 }
 458
 459 /**
 460  * g_node_reverse_children:
 461  * @node: a #GNode.
 462  *
 463  * Reverses the order of the children of a #GNode.
 464  * (It doesn't change the order of the grandchildren.)
 465  */
 466 void
 467 g_node_reverse_children (GNode *node)
 468 {
 469   GNode *child;
 470   GNode *last;
 471
 472   g_return_if_fail (node != NULL);
 473
 474   child = node->children;
 475   last = NULL;
 476   while (child)
 477     {
 478       last = child;
 479       child = last->next;
 480       last->next = last->prev;
 481       last->prev = child;
 482     }
 483   node->children = last;
 484 }
 485
 486 /**
 487  * g_node_max_height:
 488  * @root: a #GNode
 489  *
 490  * Gets the maximum height of all branches beneath a #GNode.
 491  * This is the maximum distance from the #GNode to all leaf nodes.
 492  *
 493  * If @root is %NULL, 0 is returned. If @root has no children,
 494  * 1 is returned. If @root has children, 2 is returned. And so on.
 495  *
 496  * Returns: the maximum height of the tree beneath @root
 497  */
 498 guint
 499 g_node_max_height (GNode *root)
 500 {
 501   GNode *child;
 502   guint max_height = 0;
 503
 504   if (!root)
 505     return 0;
 506
 507   child = root->children;
 508   while (child)
 509     {
 510       guint tmp_height;
 511
 512       tmp_height = g_node_max_height (child);
 513       if (tmp_height > max_height)
 514         max_height = tmp_height;
 515       child = child->next;
 516     }
 517
 518   return max_height + 1;
 519 }
 520
 521 static gboolean
 522 g_node_traverse_pre_order (GNode            *node,
 523                            GTraverseFlags    flags,
 524                            GNodeTraverseFunc func,
 525                            gpointer          data)
 526 {
 527   if (node->children)
 528     {
 529       GNode *child;
 530
 531       if ((flags & G_TRAVERSE_NON_LEAFS) &&
 532           func (node, data))
 533         return TRUE;
 534
 535       child = node->children;
 536       while (child)
 537         {
 538           GNode *current;
 539
 540           current = child;
 541           child = current->next;
 542           if (g_node_traverse_pre_order (current, flags, func, data))
 543             return TRUE;
 544         }
 545     }
 546   else if ((flags & G_TRAVERSE_LEAFS) &&
 547            func (node, data))
 548     return TRUE;
 549
 550   return FALSE;
 551 }
 552
 553 static gboolean
 554 g_node_depth_traverse_pre_order (GNode            *node,
 555                                  GTraverseFlags    flags,
 556                                  guint             depth,
 557                                  GNodeTraverseFunc func,
 558                                  gpointer          data)
 559 {
 560   if (node->children)
 561     {
 562       GNode *child;
 563
 564       if ((flags & G_TRAVERSE_NON_LEAFS) &&
 565           func (node, data))
 566         return TRUE;
 567
 568       depth--;
 569       if (!depth)
 570         return FALSE;
 571
 572       child = node->children;
 573       while (child)
 574         {
 575           GNode *current;
 576
 577           current = child;
 578           child = current->next;
 579           if (g_node_depth_traverse_pre_order (current, flags, depth, func, data))
 580             return TRUE;
 581         }
 582     }
 583   else if ((flags & G_TRAVERSE_LEAFS) &&
 584            func (node, data))
 585     return TRUE;
 586
 587   return FALSE;
 588 }
 589
 590 static gboolean
 591 g_node_traverse_post_order (GNode            *node,
 592                             GTraverseFlags    flags,
 593                             GNodeTraverseFunc func,
 594                             gpointer          data)
 595 {
 596   if (node->children)
 597     {
 598       GNode *child;
 599
 600       child = node->children;
 601       while (child)
 602         {
 603           GNode *current;
 604
 605           current = child;
 606           child = current->next;
 607           if (g_node_traverse_post_order (current, flags, func, data))
 608             return TRUE;
 609         }
 610
 611       if ((flags & G_TRAVERSE_NON_LEAFS) &&
 612           func (node, data))
 613         return TRUE;
 614
 615     }
 616   else if ((flags & G_TRAVERSE_LEAFS) &&
 617            func (node, data))
 618     return TRUE;
 619
 620   return FALSE;
 621 }
 622
 623 static gboolean
 624 g_node_depth_traverse_post_order (GNode            *node,
 625                                   GTraverseFlags    flags,
 626                                   guint             depth,
 627                                   GNodeTraverseFunc func,
 628                                   gpointer          data)
 629 {
 630   if (node->children)
 631     {
 632       depth--;
 633       if (depth)
 634         {
 635           GNode *child;
 636
 637           child = node->children;
 638           while (child)
 639             {
 640               GNode *current;
 641
 642               current = child;
 643               child = current->next;
 644               if (g_node_depth_traverse_post_order (current, flags, depth, func, data))
 645                 return TRUE;
 646             }
 647         }
 648
 649       if ((flags & G_TRAVERSE_NON_LEAFS) &&
 650           func (node, data))
 651         return TRUE;
 652
 653     }
 654   else if ((flags & G_TRAVERSE_LEAFS) &&
 655            func (node, data))
 656     return TRUE;
 657
 658   return FALSE;
 659 }
 660
 661 static gboolean
 662 g_node_traverse_in_order (GNode            *node,
 663                           GTraverseFlags    flags,
 664                           GNodeTraverseFunc func,
 665                           gpointer          data)
 666 {
 667   if (node->children)
 668     {
 669       GNode *child;
 670       GNode *current;
 671
 672       child = node->children;
 673       current = child;
 674       child = current->next;
 675
 676       if (g_node_traverse_in_order (current, flags, func, data))
 677         return TRUE;
 678
 679       if ((flags & G_TRAVERSE_NON_LEAFS) &&
 680           func (node, data))
 681         return TRUE;
 682
 683       while (child)
 684         {
 685           current = child;
 686           child = current->next;
 687           if (g_node_traverse_in_order (current, flags, func, data))
 688             return TRUE;
 689         }
 690     }
 691   else if ((flags & G_TRAVERSE_LEAFS) &&
 692            func (node, data))
 693     return TRUE;
 694
 695   return FALSE;
 696 }
 697
 698 static gboolean
 699 g_node_depth_traverse_in_order (GNode            *node,
 700                                 GTraverseFlags    flags,
 701                                 guint             depth,
 702                                 GNodeTraverseFunc func,
 703                                 gpointer          data)
 704 {
 705   if (node->children)
 706     {
 707       depth--;
 708       if (depth)
 709         {
 710           GNode *child;
 711           GNode *current;
 712
 713           child = node->children;
 714           current = child;
 715           child = current->next;
 716
 717           if (g_node_depth_traverse_in_order (current, flags, depth, func, data))
 718             return TRUE;
 719
 720           if ((flags & G_TRAVERSE_NON_LEAFS) &&
 721               func (node, data))
 722             return TRUE;
 723
 724           while (child)
 725             {
 726               current = child;
 727               child = current->next;
 728               if (g_node_depth_traverse_in_order (current, flags, depth, func, data))
 729                 return TRUE;
 730             }
 731         }
 732       else if ((flags & G_TRAVERSE_NON_LEAFS) &&
 733                func (node, data))
 734         return TRUE;
 735     }
 736   else if ((flags & G_TRAVERSE_LEAFS) &&
 737            func (node, data))
 738     return TRUE;
 739
 740   return FALSE;
 741 }
 742
 743 static gboolean
 744 g_node_traverse_level (GNode             *node,
 745                        GTraverseFlags     flags,
 746                        guint              level,
 747                        GNodeTraverseFunc  func,
 748                        gpointer           data,
 749                        gboolean          *more_levels)
 750 {
 751   if (level == 0)
 752     {
 753       if (node->children)
 754         {
 755           *more_levels = TRUE;
 756           return (flags & G_TRAVERSE_NON_LEAFS) && func (node, data);
 757         }
 758       else
 759         {
 760           return (flags & G_TRAVERSE_LEAFS) && func (node, data);
 761         }
 762     }
 763   else
 764     {
 765       node = node->children;
 766
 767       while (node)
 768         {
 769           if (g_node_traverse_level (node, flags, level - 1, func, data, more_levels))
 770             return TRUE;
 771
 772           node = node->next;
 773         }
 774     }
 775
 776   return FALSE;
 777 }
 778
 779 static gboolean
 780 g_node_depth_traverse_level (GNode             *node,
 781                              GTraverseFlags     flags,
 782                              guint              depth,
 783                              GNodeTraverseFunc  func,
 784                              gpointer           data)
 785 {
 786   guint level;
 787   gboolean more_levels;
 788
 789   level = 0;
 790   while (level != depth)
 791     {
 792       more_levels = FALSE;
 793       if (g_node_traverse_level (node, flags, level, func, data, &more_levels))
 794         return TRUE;
 795       if (!more_levels)
 796         break;
 797       level++;
 798     }
 799   return FALSE;
 800 }
 801
 802 /**
 803  * g_node_traverse:
 804  * @root: the root #GNode of the tree to traverse
 805  * @order: the order in which nodes are visited - %G_IN_ORDER,
 806  *     %G_PRE_ORDER, %G_POST_ORDER, or %G_LEVEL_ORDER.
 807  * @flags: which types of children are to be visited, one of
 808  *     %G_TRAVERSE_ALL, %G_TRAVERSE_LEAVES and %G_TRAVERSE_NON_LEAVES
 809  * @max_depth: the maximum depth of the traversal. Nodes below this
 810  *     depth will not be visited. If max_depth is -1 all nodes in
 811  *     the tree are visited. If depth is 1, only the root is visited.
 812  *     If depth is 2, the root and its children are visited. And so on.
 813  * @func: the function to call for each visited #GNode
 814  * @data: user data to pass to the function
 815  *
 816  * Traverses a tree starting at the given root #GNode.
 817  * It calls the given function for each node visited.
 818  * The traversal can be halted at any point by returning %TRUE from @func.
 819  */
 820
 821 /**
 822  * GTraverseType:
 823  * @G_IN_ORDER: vists a node's left child first, then the node itself,
 824  *              then its right child. This is the one to use if you
 825  *              want the output sorted according to the compare
 826  *              function.
 827  * @G_PRE_ORDER: visits a node, then its children.
 828  * @G_POST_ORDER: visits the node's children, then the node itself.
 829  * @G_LEVEL_ORDER: is not implemented for
 830  *              [balanced binary trees][glib-Balanced-Binary-Trees].
 831  *              For [n-ary trees][glib-N-ary-Trees], it
 832  *              vists the root node first, then its children, then
 833  *              its grandchildren, and so on. Note that this is less
 834  *              efficient than the other orders.
 835  *
 836  * Specifies the type of traveral performed by g_tree_traverse(),
 837  * g_node_traverse() and g_node_find(). The different orders are
 838  * illustrated here:
 839  * - In order: A, B, C, D, E, F, G, H, I
 840  *   ![](Sorted_binary_tree_inorder.svg)
 841  * - Pre order: F, B, A, D, C, E, G, I, H
 842  *   ![](Sorted_binary_tree_preorder.svg)
 843  * - Post order: A, C, E, D, B, H, I, G, F
 844  *   ![](Sorted_binary_tree_postorder.svg)
 845  * - Level order: F, B, G, A, D, I, C, E, H
 846  *   ![](Sorted_binary_tree_breadth-first_traversal.svg)
 847  */
 848
 849 /**
 850  * GTraverseFlags:
 851  * @G_TRAVERSE_LEAVES: only leaf nodes should be visited. This name has
 852  *                     been introduced in 2.6, for older version use
 853  *                     %G_TRAVERSE_LEAFS.
 854  * @G_TRAVERSE_NON_LEAVES: only non-leaf nodes should be visited. This
 855  *                         name has been introduced in 2.6, for older
 856  *                         version use %G_TRAVERSE_NON_LEAFS.
 857  * @G_TRAVERSE_ALL: all nodes should be visited.
 858  * @G_TRAVERSE_MASK: a mask of all traverse flags.
 859  * @G_TRAVERSE_LEAFS: identical to %G_TRAVERSE_LEAVES.
 860  * @G_TRAVERSE_NON_LEAFS: identical to %G_TRAVERSE_NON_LEAVES.
 861  *
 862  * Specifies which nodes are visited during several of the tree
 863  * functions, including g_node_traverse() and g_node_find().
 864  **/
 865 /**
 866  * GNodeTraverseFunc:
 867  * @node: a #GNode.
 868  * @data: user data passed to g_node_traverse().
 869  *
 870  * Specifies the type of function passed to g_node_traverse(). The
 871  * function is called with each of the nodes visited, together with the
 872  * user data passed to g_node_traverse(). If the function returns
 873  * %TRUE, then the traversal is stopped.
 874  *
 875  * Returns: %TRUE to stop the traversal.
 876  **/
 877 void
 878 g_node_traverse (GNode            *root,
 879                  GTraverseType     order,
 880                  GTraverseFlags    flags,
 881                  gint              depth,
 882                  GNodeTraverseFunc func,
 883                  gpointer          data)
 884 {
 885   g_return_if_fail (root != NULL);
 886   g_return_if_fail (func != NULL);
 887   g_return_if_fail (order <= G_LEVEL_ORDER);
 888   g_return_if_fail (flags <= G_TRAVERSE_MASK);
 889   g_return_if_fail (depth == -1 || depth > 0);
 890
 891   switch (order)
 892     {
 893     case G_PRE_ORDER:
 894       if (depth < 0)
 895         g_node_traverse_pre_order (root, flags, func, data);
 896       else
 897         g_node_depth_traverse_pre_order (root, flags, depth, func, data);
 898       break;
 899     case G_POST_ORDER:
 900       if (depth < 0)
 901         g_node_traverse_post_order (root, flags, func, data);
 902       else
 903         g_node_depth_traverse_post_order (root, flags, depth, func, data);
 904       break;
 905     case G_IN_ORDER:
 906       if (depth < 0)
 907         g_node_traverse_in_order (root, flags, func, data);
 908       else
 909         g_node_depth_traverse_in_order (root, flags, depth, func, data);
 910       break;
 911     case G_LEVEL_ORDER:
 912       g_node_depth_traverse_level (root, flags, depth, func, data);
 913       break;
 914     }
 915 }
 916
 917 static gboolean
 918 g_node_find_func (GNode    *node,
 919                   gpointer  data)
 920 {
 921   gpointer *d = data;
 922
 923   if (*d != node->data)
 924     return FALSE;
 925
 926   *(++d) = node;
 927
 928   return TRUE;
 929 }
 930
 931 /**
 932  * g_node_find:
 933  * @root: the root #GNode of the tree to search
 934  * @order: the order in which nodes are visited - %G_IN_ORDER,
 935  *     %G_PRE_ORDER, %G_POST_ORDER, or %G_LEVEL_ORDER
 936  * @flags: which types of children are to be searched, one of
 937  *     %G_TRAVERSE_ALL, %G_TRAVERSE_LEAVES and %G_TRAVERSE_NON_LEAVES
 938  * @data: the data to find
 939  *
 940  * Finds a #GNode in a tree.
 941  *
 942  * Returns: the found #GNode, or %NULL if the data is not found
 943  */
 944 GNode*
 945 g_node_find (GNode          *root,
 946              GTraverseType   order,
 947              GTraverseFlags  flags,
 948              gpointer        data)
 949 {
 950   gpointer d[2];
 951
 952   g_return_val_if_fail (root != NULL, NULL);
 953   g_return_val_if_fail (order <= G_LEVEL_ORDER, NULL);
 954   g_return_val_if_fail (flags <= G_TRAVERSE_MASK, NULL);
 955
 956   d[0] = data;
 957   d[1] = NULL;
 958
 959   g_node_traverse (root, order, flags, -1, g_node_find_func, d);
 960
 961   return d[1];
 962 }
 963
 964 static void
 965 g_node_count_func (GNode         *node,
 966                    GTraverseFlags flags,
 967                    guint         *n)
 968 {
 969   if (node->children)
 970     {
 971       GNode *child;
 972
 973       if (flags & G_TRAVERSE_NON_LEAFS)
 974         (*n)++;
 975
 976       child = node->children;
 977       while (child)
 978         {
 979           g_node_count_func (child, flags, n);
 980           child = child->next;
 981         }
 982     }
 983   else if (flags & G_TRAVERSE_LEAFS)
 984     (*n)++;
 985 }
 986
 987 /**
 988  * g_node_n_nodes:
 989  * @root: a #GNode
 990  * @flags: which types of children are to be counted, one of
 991  *     %G_TRAVERSE_ALL, %G_TRAVERSE_LEAVES and %G_TRAVERSE_NON_LEAVES
 992  *
 993  * Gets the number of nodes in a tree.
 994  *
 995  * Returns: the number of nodes in the tree
 996  */
 997 guint
 998 g_node_n_nodes (GNode          *root,
 999                 GTraverseFlags  flags)
1000 {
1001   guint n = 0;
1002
1003   g_return_val_if_fail (root != NULL, 0);
1004   g_return_val_if_fail (flags <= G_TRAVERSE_MASK, 0);
1005
1006   g_node_count_func (root, flags, &n);
1007
1008   return n;
1009 }
1010
1011 /**
1012  * g_node_last_child:
1013  * @node: a #GNode (must not be %NULL)
1014  *
1015  * Gets the last child of a #GNode.
1016  *
1017  * Returns: the last child of @node, or %NULL if @node has no children
1018  */
1019 GNode*
1020 g_node_last_child (GNode *node)
1021 {
1022   g_return_val_if_fail (node != NULL, NULL);
1023
1024   node = node->children;
1025   if (node)
1026     while (node->next)
1027       node = node->next;
1028
1029   return node;
1030 }
1031
1032 /**
1033  * g_node_nth_child:
1034  * @node: a #GNode
1035  * @n: the index of the desired child
1036  *
1037  * Gets a child of a #GNode, using the given index.
1038  * The first child is at index 0. If the index is
1039  * too big, %NULL is returned.
1040  *
1041  * Returns: the child of @node at index @n
1042  */
1043 GNode*
1044 g_node_nth_child (GNode *node,
1045                   guint  n)
1046 {
1047   g_return_val_if_fail (node != NULL, NULL);
1048
1049   node = node->children;
1050   if (node)
1051     while ((n-- > 0) && node)
1052       node = node->next;
1053
1054   return node;
1055 }
1056
1057 /**
1058  * g_node_n_children:
1059  * @node: a #GNode
1060  *
1061  * Gets the number of children of a #GNode.
1062  *
1063  * Returns: the number of children of @node
1064  */
1065 guint
1066 g_node_n_children (GNode *node)
1067 {
1068   guint n = 0;
1069
1070   g_return_val_if_fail (node != NULL, 0);
1071
1072   node = node->children;
1073   while (node)
1074     {
1075       n++;
1076       node = node->next;
1077     }
1078
1079   return n;
1080 }
1081
1082 /**
1083  * g_node_find_child:
1084  * @node: a #GNode
1085  * @flags: which types of children are to be searched, one of
1086  *     %G_TRAVERSE_ALL, %G_TRAVERSE_LEAVES and %G_TRAVERSE_NON_LEAVES
1087  * @data: the data to find
1088  *
1089  * Finds the first child of a #GNode with the given data.
1090  *
1091  * Returns: the found child #GNode, or %NULL if the data is not found
1092  */
1093 GNode*
1094 g_node_find_child (GNode          *node,
1095                    GTraverseFlags  flags,
1096                    gpointer        data)
1097 {
1098   g_return_val_if_fail (node != NULL, NULL);
1099   g_return_val_if_fail (flags <= G_TRAVERSE_MASK, NULL);
1100
1101   node = node->children;
1102   while (node)
1103     {
1104       if (node->data == data)
1105         {
1106           if (G_NODE_IS_LEAF (node))
1107             {
1108               if (flags & G_TRAVERSE_LEAFS)
1109                 return node;
1110             }
1111           else
1112             {
1113               if (flags & G_TRAVERSE_NON_LEAFS)
1114                 return node;
1115             }
1116         }
1117       node = node->next;
1118     }
1119
1120   return NULL;
1121 }
1122
1123 /**
1124  * g_node_child_position:
1125  * @node: a #GNode
1126  * @child: a child of @node
1127  *
1128  * Gets the position of a #GNode with respect to its siblings.
1129  * @child must be a child of @node. The first child is numbered 0,
1130  * the second 1, and so on.
1131  *
1132  * Returns: the position of @child with respect to its siblings
1133  */
1134 gint
1135 g_node_child_position (GNode *node,
1136                        GNode *child)
1137 {
1138   guint n = 0;
1139
1140   g_return_val_if_fail (node != NULL, -1);
1141   g_return_val_if_fail (child != NULL, -1);
1142   g_return_val_if_fail (child->parent == node, -1);
1143
1144   node = node->children;
1145   while (node)
1146     {
1147       if (node == child)
1148         return n;
1149       n++;
1150       node = node->next;
1151     }
1152
1153   return -1;
1154 }
1155
1156 /**
1157  * g_node_child_index:
1158  * @node: a #GNode
1159  * @data: the data to find
1160  *
1161  * Gets the position of the first child of a #GNode
1162  * which contains the given data.
1163  *
1164  * Returns: the index of the child of @node which contains
1165  *     @data, or -1 if the data is not found
1166  */
1167 gint
1168 g_node_child_index (GNode    *node,
1169                     gpointer  data)
1170 {
1171   guint n = 0;
1172
1173   g_return_val_if_fail (node != NULL, -1);
1174
1175   node = node->children;
1176   while (node)
1177     {
1178       if (node->data == data)
1179         return n;
1180       n++;
1181       node = node->next;
1182     }
1183
1184   return -1;
1185 }
1186
1187 /**
1188  * g_node_first_sibling:
1189  * @node: a #GNode
1190  *
1191  * Gets the first sibling of a #GNode.
1192  * This could possibly be the node itself.
1193  *
1194  * Returns: the first sibling of @node
1195  */
1196 GNode*
1197 g_node_first_sibling (GNode *node)
1198 {
1199   g_return_val_if_fail (node != NULL, NULL);
1200
1201   if (node->parent)
1202     return node->parent->children;
1203
1204   while (node->prev)
1205     node = node->prev;
1206
1207   return node;
1208 }
1209
1210 /**
1211  * g_node_last_sibling:
1212  * @node: a #GNode
1213  *
1214  * Gets the last sibling of a #GNode.
1215  * This could possibly be the node itself.
1216  *
1217  * Returns: the last sibling of @node
1218  */
1219 GNode*
1220 g_node_last_sibling (GNode *node)
1221 {
1222   g_return_val_if_fail (node != NULL, NULL);
1223
1224   while (node->next)
1225     node = node->next;
1226
1227   return node;
1228 }
1229
1230 /**
1231  * g_node_children_foreach:
1232  * @node: a #GNode
1233  * @flags: which types of children are to be visited, one of
1234  *     %G_TRAVERSE_ALL, %G_TRAVERSE_LEAVES and %G_TRAVERSE_NON_LEAVES
1235  * @func: the function to call for each visited node
1236  * @data: user data to pass to the function
1237  *
1238  * Calls a function for each of the children of a #GNode.
1239  * Note that it doesn't descend beneath the child nodes.
1240  */
1241 /**
1242  * GNodeForeachFunc:
1243  * @node: a #GNode.
1244  * @data: user data passed to g_node_children_foreach().
1245  *
1246  * Specifies the type of function passed to g_node_children_foreach().
1247  * The function is called with each child node, together with the user
1248  * data passed to g_node_children_foreach().
1249  **/
1250 void
1251 g_node_children_foreach (GNode            *node,
1252                          GTraverseFlags    flags,
1253                          GNodeForeachFunc  func,
1254                          gpointer          data)
1255 {
1256   g_return_if_fail (node != NULL);
1257   g_return_if_fail (flags <= G_TRAVERSE_MASK);
1258   g_return_if_fail (func != NULL);
1259
1260   node = node->children;
1261   while (node)
1262     {
1263       GNode *current;
1264
1265       current = node;
1266       node = current->next;
1267       if (G_NODE_IS_LEAF (current))
1268         {
1269           if (flags & G_TRAVERSE_LEAFS)
1270             func (current, data);
1271         }
1272       else
1273         {
1274           if (flags & G_TRAVERSE_NON_LEAFS)
1275             func (current, data);
1276         }
1277     }
1278 }