wmfu/list.h

   1 /*
   2  * Copyright (c) 2007 Daniel Borca  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program 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
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18
  19
  20 #ifndef LIST_H_included
  21 #define LIST_H_included
  22
  23 /**
  24  * Remove an element from list.
  25  *
  26  * \param elem element to remove.
  27  */
  28 #define list_remove(elem)                       \
  29 do {                                            \
  30     (elem)->next->prev = (elem)->prev;          \
  31     (elem)->prev->next = (elem)->next;          \
  32 } while (0)
  33
  34 /**
  35  * Insert an element to the list head.
  36  *
  37  * \param list list.
  38  * \param elem element to insert.
  39  */
  40 #define list_prepend(list, elem)                \
  41 do {                                            \
  42     (elem)->prev = list;                        \
  43     (elem)->next = (list)->next;                \
  44     (list)->next->prev = elem;                  \
  45     (list)->next = elem;                        \
  46 } while(0)
  47
  48 /**
  49  * Insert an element to the list tail.
  50  *
  51  * \param list list.
  52  * \param elem element to insert.
  53  */
  54 #define list_append(list, elem)                 \
  55 do {                                            \
  56     (elem)->next = list;                        \
  57     (elem)->prev = (list)->prev;                \
  58     (list)->prev->next = elem;                  \
  59     (list)->prev = elem;                        \
  60 } while(0)
  61
  62 /**
  63  * Make a empty list empty.
  64  *
  65  * \param sentinel list (sentinel element).
  66  */
  67 #define list_create(sentinel)                   \
  68 do {                                            \
  69     (sentinel)->next = sentinel;                \
  70     (sentinel)->prev = sentinel;                \
  71 } while (0)
  72
  73 /**
  74  * Get list first element.
  75  *
  76  * \param list list.
  77  *
  78  * \return pointer to first element.
  79  */
  80 #define list_first(list)        ((list)->next)
  81
  82 /**
  83  * Get list last element.
  84  *
  85  * \param list list.
  86  *
  87  * \return pointer to last element.
  88  */
  89 #define list_last(list)         ((list)->prev)
  90
  91 /**
  92  * Get next element.
  93  *
  94  * \param elem element.
  95  *
  96  * \return pointer to next element.
  97  */
  98 #define list_next(elem)         ((elem)->next)
  99
 100 /**
 101  * Get previous element.
 102  *
 103  * \param elem element.
 104  *
 105  * \return pointer to previous element.
 106  */
 107 #define list_prev(elem)         ((elem)->prev)
 108
 109 /**
 110  * Test whether element is at end of the list.
 111  *
 112  * \param list list.
 113  * \param elem element.
 114  *
 115  * \return non-zero if element is at end of list, or zero otherwise.
 116  */
 117 #define list_at_end(list, elem) ((elem) == (list))
 118
 119 /**
 120  * Test if a list is empty.
 121  *
 122  * \param list list.
 123  *
 124  * \return non-zero if list empty, or zero otherwise.
 125  */
 126 #define list_is_empty(list)     ((list)->next == (list))
 127
 128 /**
 129  * Walk through the elements of a list.
 130  *
 131  * \param ptr pointer to the current element.
 132  * \param list list.
 133  *
 134  * \note It should be followed by a { } block or a single statement, as in a \c
 135  * for loop.
 136  */
 137 #define list_foreach(ptr, list)\
 138     for (ptr = (list)->next; ptr != list;  ptr = (ptr)->next)
 139
 140 /**
 141  * Walk through the elements of a list.
 142  *
 143  * Same as #foreach but lets you unlink the current value during a list
 144  * traversal.  Useful for freeing a list, element by element.
 145  *
 146  * \param ptr pointer to the current element.
 147  * \param t temporary pointer.
 148  * \param list list.
 149  *
 150  * \note It should be followed by a { } block or a single statement, as in a \c
 151  * for loop.
 152  */
 153 #define list_foreach_s(ptr, t, list)\
 154     for (ptr = (list)->next, t = (ptr)->next; list != ptr; ptr = t, t = (t)->next)
 155
 156 #endif