glib/gslist.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 #include "config.h"
  32
  33 #include "gslist.h"
  34
  35 #include "gtestutils.h"
  36 #include "gslice.h"
  37
  38 /**
  39  * SECTION:linked_lists_single
  40  * @title: Singly-Linked Lists
  41  * @short_description: linked lists that can be iterated in one direction
  42  *
  43  * The #GSList structure and its associated functions provide a
  44  * standard singly-linked list data structure.
  45  *
  46  * Each element in the list contains a piece of data, together with a
  47  * pointer which links to the next element in the list. Using this
  48  * pointer it is possible to move through the list in one direction
  49  * only (unlike the <link
  50  * linkend="glib-Doubly-Linked-Lists">Doubly-Linked Lists</link> which
  51  * allow movement in both directions).
  52  *
  53  * The data contained in each element can be either integer values, by
  54  * using one of the <link linkend="glib-Type-Conversion-Macros">Type
  55  * Conversion Macros</link>, or simply pointers to any type of data.
  56  *
  57  * List elements are allocated from the <link
  58  * linkend="glib-Memory-Slices">slice allocator</link>, which is more
  59  * efficient than allocating elements individually.
  60  *
  61  * Note that most of the #GSList functions expect to be passed a
  62  * pointer to the first element in the list. The functions which insert
  63  * elements return the new start of the list, which may have changed.
  64  *
  65  * There is no function to create a #GSList. %NULL is considered to be
  66  * the empty list so you simply set a #GSList* to %NULL.
  67  *
  68  * To add elements, use g_slist_append(), g_slist_prepend(),
  69  * g_slist_insert() and g_slist_insert_sorted().
  70  *
  71  * To remove elements, use g_slist_remove().
  72  *
  73  * To find elements in the list use g_slist_last(), g_slist_next(),
  74  * g_slist_nth(), g_slist_nth_data(), g_slist_find() and
  75  * g_slist_find_custom().
  76  *
  77  * To find the index of an element use g_slist_position() and
  78  * g_slist_index().
  79  *
  80  * To call a function for each element in the list use
  81  * g_slist_foreach().
  82  *
  83  * To free the entire list, use g_slist_free().
  84  **/
  85
  86 /**
  87  * GSList:
  88  * @data: holds the element's data, which can be a pointer to any kind
  89  *        of data, or any integer value using the <link
  90  *        linkend="glib-Type-Conversion-Macros">Type Conversion
  91  *        Macros</link>.
  92  * @next: contains the link to the next element in the list.
  93  *
  94  * The #GSList struct is used for each element in the singly-linked
  95  * list.
  96  **/
  97
  98 /**
  99  * g_slist_next:
 100  * @slist: an element in a #GSList.
 101  * @Returns: the next element, or %NULL if there are no more elements.
 102  *
 103  * A convenience macro to get the next element in a #GSList.
 104  **/
 105
 106 #define _g_slist_alloc0()       g_slice_new0 (GSList)
 107 #define _g_slist_alloc()        g_slice_new (GSList)
 108 #define _g_slist_free1(slist)   g_slice_free (GSList, slist)
 109
 110 /**
 111  * g_slist_alloc:
 112  * @Returns: a pointer to the newly-allocated #GSList element.
 113  *
 114  * Allocates space for one #GSList element. It is called by the
 115  * g_slist_append(), g_slist_prepend(), g_slist_insert() and
 116  * g_slist_insert_sorted() functions and so is rarely used on its own.
 117  **/
 118 GSList*
 119 g_slist_alloc (void)
 120 {
 121   return _g_slist_alloc0 ();
 122 }
 123
 124 /**
 125  * g_slist_free:
 126  * @list: a #GSList
 127  *
 128  * Frees all of the memory used by a #GSList.
 129  * The freed elements are returned to the slice allocator.
 130  *
 131  * <note><para>
 132  * If list elements contain dynamically-allocated memory,
 133  * you should either use g_slist_free_full() or free them manually
 134  * first.
 135  * </para></note>
 136  */
 137 void
 138 g_slist_free (GSList *list)
 139 {
 140   g_slice_free_chain (GSList, list, next);
 141 }
 142
 143 /**
 144  * g_slist_free_1:
 145  * @list: a #GSList element
 146  *
 147  * Frees one #GSList element.
 148  * It is usually used after g_slist_remove_link().
 149  */
 150 /**
 151  * g_slist_free1:
 152  *
 153  * A macro which does the same as g_slist_free_1().
 154  *
 155  * Since: 2.10
 156  **/
 157 void
 158 g_slist_free_1 (GSList *list)
 159 {
 160   _g_slist_free1 (list);
 161 }
 162
 163 /**
 164  * g_slist_free_full:
 165  * @list: a pointer to a #GSList
 166  * @free_func: the function to be called to free each element's data
 167  *
 168  * Convenience method, which frees all the memory used by a #GSList, and
 169  * calls the specified destroy function on every element's data.
 170  *
 171  * Since: 2.28
 172  **/
 173 void
 174 g_slist_free_full (GSList         *list,
 175                    GDestroyNotify  free_func)
 176 {
 177   g_slist_foreach (list, (GFunc) free_func, NULL);
 178   g_slist_free (list);
 179 }
 180
 181 /**
 182  * g_slist_append:
 183  * @list: a #GSList
 184  * @data: the data for the new element
 185  *
 186  * Adds a new element on to the end of the list.
 187  *
 188  * <note><para>
 189  * The return value is the new start of the list, which may
 190  * have changed, so make sure you store the new value.
 191  * </para></note>
 192  *
 193  * <note><para>
 194  * Note that g_slist_append() has to traverse the entire list
 195  * to find the end, which is inefficient when adding multiple
 196  * elements. A common idiom to avoid the inefficiency is to prepend
 197  * the elements and reverse the list when all elements have been added.
 198  * </para></note>
 199  *
 200  * |[
 201  * /&ast; Notice that these are initialized to the empty list. &ast;/
 202  * GSList *list = NULL, *number_list = NULL;
 203  *
 204  * /&ast; This is a list of strings. &ast;/
 205  * list = g_slist_append (list, "first");
 206  * list = g_slist_append (list, "second");
 207  *
 208  * /&ast; This is a list of integers. &ast;/
 209  * number_list = g_slist_append (number_list, GINT_TO_POINTER (27));
 210  * number_list = g_slist_append (number_list, GINT_TO_POINTER (14));
 211  * ]|
 212  *
 213  * Returns: the new start of the #GSList
 214  */
 215 GSList*
 216 g_slist_append (GSList   *list,
 217                 gpointer  data)
 218 {
 219   GSList *new_list;
 220   GSList *last;
 221
 222   new_list = _g_slist_alloc ();
 223   new_list->data = data;
 224   new_list->next = NULL;
 225
 226   if (list)
 227     {
 228       last = g_slist_last (list);
 229       /* g_assert (last != NULL); */
 230       last->next = new_list;
 231
 232       return list;
 233     }
 234   else
 235     return new_list;
 236 }
 237
 238 /**
 239  * g_slist_prepend:
 240  * @list: a #GSList
 241  * @data: the data for the new element
 242  *
 243  * Adds a new element on to the start of the list.
 244  *
 245  * <note><para>
 246  * The return value is the new start of the list, which
 247  * may have changed, so make sure you store the new value.
 248  * </para></note>
 249  *
 250  * |[
 251  * /&ast; Notice that it is initialized to the empty list. &ast;/
 252  * GSList *list = NULL;
 253  * list = g_slist_prepend (list, "last");
 254  * list = g_slist_prepend (list, "first");
 255  * ]|
 256  *
 257  * Returns: the new start of the #GSList
 258  */
 259 GSList*
 260 g_slist_prepend (GSList   *list,
 261                  gpointer  data)
 262 {
 263   GSList *new_list;
 264
 265   new_list = _g_slist_alloc ();
 266   new_list->data = data;
 267   new_list->next = list;
 268
 269   return new_list;
 270 }
 271
 272 /**
 273  * g_slist_insert:
 274  * @list: a #GSList
 275  * @data: the data for the new element
 276  * @position: the position to insert the element.
 277  *     If this is negative, or is larger than the number
 278  *     of elements in the list, the new element is added on
 279  *     to the end of the list.
 280  *
 281  * Inserts a new element into the list at the given position.
 282  *
 283  * Returns: the new start of the #GSList
 284  */
 285 GSList*
 286 g_slist_insert (GSList   *list,
 287                 gpointer  data,
 288                 gint      position)
 289 {
 290   GSList *prev_list;
 291   GSList *tmp_list;
 292   GSList *new_list;
 293
 294   if (position < 0)
 295     return g_slist_append (list, data);
 296   else if (position == 0)
 297     return g_slist_prepend (list, data);
 298
 299   new_list = _g_slist_alloc ();
 300   new_list->data = data;
 301
 302   if (!list)
 303     {
 304       new_list->next = NULL;
 305       return new_list;
 306     }
 307
 308   prev_list = NULL;
 309   tmp_list = list;
 310
 311   while ((position-- > 0) && tmp_list)
 312     {
 313       prev_list = tmp_list;
 314       tmp_list = tmp_list->next;
 315     }
 316
 317   new_list->next = prev_list->next;
 318   prev_list->next = new_list;
 319
 320   return list;
 321 }
 322
 323 /**
 324  * g_slist_insert_before:
 325  * @slist: a #GSList
 326  * @sibling: node to insert @data before
 327  * @data: data to put in the newly-inserted node
 328  *
 329  * Inserts a node before @sibling containing @data.
 330  *
 331  * Returns: the new head of the list.
 332  */
 333 GSList*
 334 g_slist_insert_before (GSList  *slist,
 335                        GSList  *sibling,
 336                        gpointer data)
 337 {
 338   if (!slist)
 339     {
 340       slist = _g_slist_alloc ();
 341       slist->data = data;
 342       slist->next = NULL;
 343       g_return_val_if_fail (sibling == NULL, slist);
 344       return slist;
 345     }
 346   else
 347     {
 348       GSList *node, *last = NULL;
 349
 350       for (node = slist; node; last = node, node = last->next)
 351         if (node == sibling)
 352           break;
 353       if (!last)
 354         {
 355           node = _g_slist_alloc ();
 356           node->data = data;
 357           node->next = slist;
 358
 359           return node;
 360         }
 361       else
 362         {
 363           node = _g_slist_alloc ();
 364           node->data = data;
 365           node->next = last->next;
 366           last->next = node;
 367
 368           return slist;
 369         }
 370     }
 371 }
 372
 373 /**
 374  * g_slist_concat:
 375  * @list1: a #GSList
 376  * @list2: the #GSList to add to the end of the first #GSList
 377  *
 378  * Adds the second #GSList onto the end of the first #GSList.
 379  * Note that the elements of the second #GSList are not copied.
 380  * They are used directly.
 381  *
 382  * Returns: the start of the new #GSList
 383  */
 384 GSList *
 385 g_slist_concat (GSList *list1, GSList *list2)
 386 {
 387   if (list2)
 388     {
 389       if (list1)
 390         g_slist_last (list1)->next = list2;
 391       else
 392         list1 = list2;
 393     }
 394
 395   return list1;
 396 }
 397
 398 /**
 399  * g_slist_remove:
 400  * @list: a #GSList
 401  * @data: the data of the element to remove
 402  *
 403  * Removes an element from a #GSList.
 404  * If two elements contain the same data, only the first is removed.
 405  * If none of the elements contain the data, the #GSList is unchanged.
 406  *
 407  * Returns: the new start of the #GSList
 408  */
 409 GSList*
 410 g_slist_remove (GSList        *list,
 411                 gconstpointer  data)
 412 {
 413   GSList *tmp, *prev = NULL;
 414
 415   tmp = list;
 416   while (tmp)
 417     {
 418       if (tmp->data == data)
 419         {
 420           if (prev)
 421             prev->next = tmp->next;
 422           else
 423             list = tmp->next;
 424
 425           g_slist_free_1 (tmp);
 426           break;
 427         }
 428       prev = tmp;
 429       tmp = prev->next;
 430     }
 431
 432   return list;
 433 }
 434
 435 /**
 436  * g_slist_remove_all:
 437  * @list: a #GSList
 438  * @data: data to remove
 439  *
 440  * Removes all list nodes with data equal to @data.
 441  * Returns the new head of the list. Contrast with
 442  * g_slist_remove() which removes only the first node
 443  * matching the given data.
 444  *
 445  * Returns: new head of @list
 446  */
 447 GSList*
 448 g_slist_remove_all (GSList        *list,
 449                     gconstpointer  data)
 450 {
 451   GSList *tmp, *prev = NULL;
 452
 453   tmp = list;
 454   while (tmp)
 455     {
 456       if (tmp->data == data)
 457         {
 458           GSList *next = tmp->next;
 459
 460           if (prev)
 461             prev->next = next;
 462           else
 463             list = next;
 464
 465           g_slist_free_1 (tmp);
 466           tmp = next;
 467         }
 468       else
 469         {
 470           prev = tmp;
 471           tmp = prev->next;
 472         }
 473     }
 474
 475   return list;
 476 }
 477
 478 static inline GSList*
 479 _g_slist_remove_link (GSList *list,
 480                       GSList *link)
 481 {
 482   GSList *tmp;
 483   GSList *prev;
 484
 485   prev = NULL;
 486   tmp = list;
 487
 488   while (tmp)
 489     {
 490       if (tmp == link)
 491         {
 492           if (prev)
 493             prev->next = tmp->next;
 494           if (list == tmp)
 495             list = list->next;
 496
 497           tmp->next = NULL;
 498           break;
 499         }
 500
 501       prev = tmp;
 502       tmp = tmp->next;
 503     }
 504
 505   return list;
 506 }
 507
 508 /**
 509  * g_slist_remove_link:
 510  * @list: a #GSList
 511  * @link_: an element in the #GSList
 512  *
 513  * Removes an element from a #GSList, without
 514  * freeing the element. The removed element's next
 515  * link is set to %NULL, so that it becomes a
 516  * self-contained list with one element.
 517  *
 518  * Returns: the new start of the #GSList, without the element
 519  */
 520 GSList*
 521 g_slist_remove_link (GSList *list,
 522                      GSList *link_)
 523 {
 524   return _g_slist_remove_link (list, link_);
 525 }
 526
 527 /**
 528  * g_slist_delete_link:
 529  * @list: a #GSList
 530  * @link_: node to delete
 531  *
 532  * Removes the node link_ from the list and frees it.
 533  * Compare this to g_slist_remove_link() which removes the node
 534  * without freeing it.
 535  *
 536  * Returns: the new head of @list
 537  */
 538 GSList*
 539 g_slist_delete_link (GSList *list,
 540                      GSList *link_)
 541 {
 542   list = _g_slist_remove_link (list, link_);
 543   _g_slist_free1 (link_);
 544
 545   return list;
 546 }
 547
 548 /**
 549  * g_slist_copy:
 550  * @list: a #GSList
 551  *
 552  * Copies a #GSList.
 553  *
 554  * <note><para>
 555  * Note that this is a "shallow" copy. If the list elements
 556  * consist of pointers to data, the pointers are copied but
 557  * the actual data isn't.
 558  * </para></note>
 559  *
 560  * Returns: a copy of @list
 561  */
 562 GSList*
 563 g_slist_copy (GSList *list)
 564 {
 565   GSList *new_list = NULL;
 566
 567   if (list)
 568     {
 569       GSList *last;
 570
 571       new_list = _g_slist_alloc ();
 572       new_list->data = list->data;
 573       last = new_list;
 574       list = list->next;
 575       while (list)
 576         {
 577           last->next = _g_slist_alloc ();
 578           last = last->next;
 579           last->data = list->data;
 580           list = list->next;
 581         }
 582       last->next = NULL;
 583     }
 584
 585   return new_list;
 586 }
 587
 588 /**
 589  * g_slist_reverse:
 590  * @list: a #GSList
 591  *
 592  * Reverses a #GSList.
 593  *
 594  * Returns: the start of the reversed #GSList
 595  */
 596 GSList*
 597 g_slist_reverse (GSList *list)
 598 {
 599   GSList *prev = NULL;
 600
 601   while (list)
 602     {
 603       GSList *next = list->next;
 604
 605       list->next = prev;
 606
 607       prev = list;
 608       list = next;
 609     }
 610
 611   return prev;
 612 }
 613
 614 /**
 615  * g_slist_nth:
 616  * @list: a #GSList
 617  * @n: the position of the element, counting from 0
 618  *
 619  * Gets the element at the given position in a #GSList.
 620  *
 621  * Returns: the element, or %NULL if the position is off
 622  *     the end of the #GSList
 623  */
 624 GSList*
 625 g_slist_nth (GSList *list,
 626              guint   n)
 627 {
 628   while (n-- > 0 && list)
 629     list = list->next;
 630
 631   return list;
 632 }
 633
 634 /**
 635  * g_slist_nth_data:
 636  * @list: a #GSList
 637  * @n: the position of the element
 638  *
 639  * Gets the data of the element at the given position.
 640  *
 641  * Returns: the element's data, or %NULL if the position
 642  *     is off the end of the #GSList
 643  */
 644 gpointer
 645 g_slist_nth_data (GSList   *list,
 646                   guint     n)
 647 {
 648   while (n-- > 0 && list)
 649     list = list->next;
 650
 651   return list ? list->data : NULL;
 652 }
 653
 654 /**
 655  * g_slist_find:
 656  * @list: a #GSList
 657  * @data: the element data to find
 658  *
 659  * Finds the element in a #GSList which
 660  * contains the given data.
 661  *
 662  * Returns: the found #GSList element,
 663  *     or %NULL if it is not found
 664  */
 665 GSList*
 666 g_slist_find (GSList        *list,
 667               gconstpointer  data)
 668 {
 669   while (list)
 670     {
 671       if (list->data == data)
 672         break;
 673       list = list->next;
 674     }
 675
 676   return list;
 677 }
 678
 679
 680 /**
 681  * g_slist_find_custom:
 682  * @list: a #GSList
 683  * @data: user data passed to the function
 684  * @func: the function to call for each element.
 685  *     It should return 0 when the desired element is found
 686  *
 687  * Finds an element in a #GSList, using a supplied function to
 688  * find the desired element. It iterates over the list, calling
 689  * the given function which should return 0 when the desired
 690  * element is found. The function takes two #gconstpointer arguments,
 691  * the #GSList element's data as the first argument and the
 692  * given user data.
 693  *
 694  * Returns: the found #GSList element, or %NULL if it is not found
 695  */
 696 GSList*
 697 g_slist_find_custom (GSList        *list,
 698                      gconstpointer  data,
 699                      GCompareFunc   func)
 700 {
 701   g_return_val_if_fail (func != NULL, list);
 702
 703   while (list)
 704     {
 705       if (! func (list->data, data))
 706         return list;
 707       list = list->next;
 708     }
 709
 710   return NULL;
 711 }
 712
 713 /**
 714  * g_slist_position:
 715  * @list: a #GSList
 716  * @llink: an element in the #GSList
 717  *
 718  * Gets the position of the given element
 719  * in the #GSList (starting from 0).
 720  *
 721  * Returns: the position of the element in the #GSList,
 722  *     or -1 if the element is not found
 723  */
 724 gint
 725 g_slist_position (GSList *list,
 726                   GSList *llink)
 727 {
 728   gint i;
 729
 730   i = 0;
 731   while (list)
 732     {
 733       if (list == llink)
 734         return i;
 735       i++;
 736       list = list->next;
 737     }
 738
 739   return -1;
 740 }
 741
 742 /**
 743  * g_slist_index:
 744  * @list: a #GSList
 745  * @data: the data to find
 746  *
 747  * Gets the position of the element containing
 748  * the given data (starting from 0).
 749  *
 750  * Returns: the index of the element containing the data,
 751  *     or -1 if the data is not found
 752  */
 753 gint
 754 g_slist_index (GSList        *list,
 755                gconstpointer  data)
 756 {
 757   gint i;
 758
 759   i = 0;
 760   while (list)
 761     {
 762       if (list->data == data)
 763         return i;
 764       i++;
 765       list = list->next;
 766     }
 767
 768   return -1;
 769 }
 770
 771 /**
 772  * g_slist_last:
 773  * @list: a #GSList
 774  *
 775  * Gets the last element in a #GSList.
 776  *
 777  * <note><para>
 778  * This function iterates over the whole list.
 779  * </para></note>
 780  *
 781  * Returns: the last element in the #GSList,
 782  *     or %NULL if the #GSList has no elements
 783  */
 784 GSList*
 785 g_slist_last (GSList *list)
 786 {
 787   if (list)
 788     {
 789       while (list->next)
 790         list = list->next;
 791     }
 792
 793   return list;
 794 }
 795
 796 /**
 797  * g_slist_length:
 798  * @list: a #GSList
 799  *
 800  * Gets the number of elements in a #GSList.
 801  *
 802  * <note><para>
 803  * This function iterates over the whole list to
 804  * count its elements.
 805  * </para></note>
 806  *
 807  * Returns: the number of elements in the #GSList
 808  */
 809 guint
 810 g_slist_length (GSList *list)
 811 {
 812   guint length;
 813
 814   length = 0;
 815   while (list)
 816     {
 817       length++;
 818       list = list->next;
 819     }
 820
 821   return length;
 822 }
 823
 824 /**
 825  * g_slist_foreach:
 826  * @list: a #GSList
 827  * @func: the function to call with each element's data
 828  * @user_data: user data to pass to the function
 829  *
 830  * Calls a function for each element of a #GSList.
 831  */
 832 void
 833 g_slist_foreach (GSList   *list,
 834                  GFunc     func,
 835                  gpointer  user_data)
 836 {
 837   while (list)
 838     {
 839       GSList *next = list->next;
 840       (*func) (list->data, user_data);
 841       list = next;
 842     }
 843 }
 844
 845 static GSList*
 846 g_slist_insert_sorted_real (GSList   *list,
 847                             gpointer  data,
 848                             GFunc     func,
 849                             gpointer  user_data)
 850 {
 851   GSList *tmp_list = list;
 852   GSList *prev_list = NULL;
 853   GSList *new_list;
 854   gint cmp;
 855
 856   g_return_val_if_fail (func != NULL, list);
 857
 858   if (!list)
 859     {
 860       new_list = _g_slist_alloc ();
 861       new_list->data = data;
 862       new_list->next = NULL;
 863       return new_list;
 864     }
 865
 866   cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
 867
 868   while ((tmp_list->next) && (cmp > 0))
 869     {
 870       prev_list = tmp_list;
 871       tmp_list = tmp_list->next;
 872
 873       cmp = ((GCompareDataFunc) func) (data, tmp_list->data, user_data);
 874     }
 875
 876   new_list = _g_slist_alloc ();
 877   new_list->data = data;
 878
 879   if ((!tmp_list->next) && (cmp > 0))
 880     {
 881       tmp_list->next = new_list;
 882       new_list->next = NULL;
 883       return list;
 884     }
 885
 886   if (prev_list)
 887     {
 888       prev_list->next = new_list;
 889       new_list->next = tmp_list;
 890       return list;
 891     }
 892   else
 893     {
 894       new_list->next = list;
 895       return new_list;
 896     }
 897 }
 898
 899 /**
 900  * g_slist_insert_sorted:
 901  * @list: a #GSList
 902  * @data: the data for the new element
 903  * @func: the function to compare elements in the list.
 904  *     It should return a number > 0 if the first parameter
 905  *     comes after the second parameter in the sort order.
 906  *
 907  * Inserts a new element into the list, using the given
 908  * comparison function to determine its position.
 909  *
 910  * Returns: the new start of the #GSList
 911  */
 912 GSList*
 913 g_slist_insert_sorted (GSList       *list,
 914                        gpointer      data,
 915                        GCompareFunc  func)
 916 {
 917   return g_slist_insert_sorted_real (list, data, (GFunc) func, NULL);
 918 }
 919
 920 /**
 921  * g_slist_insert_sorted_with_data:
 922  * @list: a #GSList
 923  * @data: the data for the new element
 924  * @func: the function to compare elements in the list.
 925  *     It should return a number > 0 if the first parameter
 926  *     comes after the second parameter in the sort order.
 927  * @user_data: data to pass to comparison function
 928  *
 929  * Inserts a new element into the list, using the given
 930  * comparison function to determine its position.
 931  *
 932  * Returns: the new start of the #GSList
 933  *
 934  * Since: 2.10
 935  */
 936 GSList*
 937 g_slist_insert_sorted_with_data (GSList           *list,
 938                                  gpointer          data,
 939                                  GCompareDataFunc  func,
 940                                  gpointer          user_data)
 941 {
 942   return g_slist_insert_sorted_real (list, data, (GFunc) func, user_data);
 943 }
 944
 945 static GSList *
 946 g_slist_sort_merge (GSList   *l1,
 947                     GSList   *l2,
 948                     GFunc     compare_func,
 949                     gpointer  user_data)
 950 {
 951   GSList list, *l;
 952   gint cmp;
 953
 954   l=&list;
 955
 956   while (l1 && l2)
 957     {
 958       cmp = ((GCompareDataFunc) compare_func) (l1->data, l2->data, user_data);
 959
 960       if (cmp <= 0)
 961         {
 962           l=l->next=l1;
 963           l1=l1->next;
 964         }
 965       else
 966         {
 967           l=l->next=l2;
 968           l2=l2->next;
 969         }
 970     }
 971   l->next= l1 ? l1 : l2;
 972
 973   return list.next;
 974 }
 975
 976 static GSList *
 977 g_slist_sort_real (GSList   *list,
 978                    GFunc     compare_func,
 979                    gpointer  user_data)
 980 {
 981   GSList *l1, *l2;
 982
 983   if (!list)
 984     return NULL;
 985   if (!list->next)
 986     return list;
 987
 988   l1 = list;
 989   l2 = list->next;
 990
 991   while ((l2 = l2->next) != NULL)
 992     {
 993       if ((l2 = l2->next) == NULL)
 994         break;
 995       l1=l1->next;
 996     }
 997   l2 = l1->next;
 998   l1->next = NULL;
 999
1000   return g_slist_sort_merge (g_slist_sort_real (list, compare_func, user_data),
1001                              g_slist_sort_real (l2, compare_func, user_data),
1002                              compare_func,
1003                              user_data);
1004 }
1005
1006 /**
1007  * g_slist_sort:
1008  * @list: a #GSList
1009  * @compare_func: the comparison function used to sort the #GSList.
1010  *     This function is passed the data from 2 elements of the #GSList
1011  *     and should return 0 if they are equal, a negative value if the
1012  *     first element comes before the second, or a positive value if
1013  *     the first element comes after the second.
1014  *
1015  * Sorts a #GSList using the given comparison function.
1016  *
1017  * Returns: the start of the sorted #GSList
1018  */
1019 GSList *
1020 g_slist_sort (GSList       *list,
1021               GCompareFunc  compare_func)
1022 {
1023   return g_slist_sort_real (list, (GFunc) compare_func, NULL);
1024 }
1025
1026 /**
1027  * g_slist_sort_with_data:
1028  * @list: a #GSList
1029  * @compare_func: comparison function
1030  * @user_data: data to pass to comparison function
1031  *
1032  * Like g_slist_sort(), but the sort function accepts a user data argument.
1033  *
1034  * Returns: new head of the list
1035  */
1036 GSList *
1037 g_slist_sort_with_data (GSList           *list,
1038                         GCompareDataFunc  compare_func,
1039                         gpointer          user_data)
1040 {
1041   return g_slist_sort_real (list, (GFunc) compare_func, user_data);
1042 }