kc3-lang/libxkbcommon/src/list.h

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• Author : Ran Benita
  Date : 2012-07-20 12:48:13
  Hash : 2fc0ad50
  Message : Fix bison 2.6 and clang warnings Signed-off-by: Ran Benita <ran234@gmail.com>

• src/list.h

• /*
   * Copyright © 2010 Intel Corporation
   * Copyright © 2010 Francisco Jerez <currojerez@riseup.net>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   *
   */
  
  #ifndef LIST_H
  #define LIST_H
  
  /**
   * @file Classic doubly-link circular list implementation.
   * For real usage examples of the linked list, see the file test/list.c
   *
   * Example:
   * We need to keep a list of struct foo in the parent struct bar, i.e. what
   * we want is something like this.
   *
   *     struct bar {
   *          ...
   *          struct foo *list_of_foos; -----> struct foo {}, struct foo {}, struct foo{}
   *          ...
   *     }
   *
   * We need one list head in bar and a list element in all list_of_foos (both are of
   * data type 'struct list').
   *
   *     struct bar {
   *          ...
   *          struct list list_of_foos;
   *          ...
   *     }
   *
   *     struct foo {
   *          ...
   *          struct list entry;
   *          ...
   *     }
   *
   * Now we initialize the list head:
   *
   *     struct bar bar;
   *     ...
   *     list_init(&bar.list_of_foos);
   *
   * Then we create the first element and add it to this list:
   *
   *     struct foo *foo = malloc(...);
   *     ....
   *     list_add(&foo->entry, &bar.list_of_foos);
   *
   * Repeat the above for each element you want to add to the list. Deleting
   * works with the element itself.
   *      list_del(&foo->entry);
   *      free(foo);
   *
   * Note: calling list_del(&bar.list_of_foos) will set bar.list_of_foos to an empty
   * list again.
   *
   * Looping through the list requires a 'struct foo' as iterator and the
   * name of the field the subnodes use.
   *
   * struct foo *iterator;
   * list_foreach(iterator, &bar.list_of_foos, entry) {
   *      if (iterator->something == ...)
   *             ...
   * }
   *
   * Note: You must not call list_del() on the iterator if you continue the
   * loop. You need to run the safe for-each loop instead:
   *
   * struct foo *iterator, *next;
   * list_foreach_safe(iterator, next, &bar.list_of_foos, entry) {
   *      if (...)
   *              list_del(&iterator->entry);
   * }
   *
   */
  
  /**
   * The linkage struct for list nodes. This struct must be part of your
   * to-be-linked struct. struct list is required for both the head of the
   * list and for each list node.
   *
   * Position and name of the struct list field is irrelevant.
   * There are no requirements that elements of a list are of the same type.
   * There are no requirements for a list head, any struct list can be a list
   * head.
   */
  struct list {
      struct list *next, *prev;
  };
  
  /**
   * Initialize the list as an empty list.
   *
   * Example:
   * list_init(&bar->list_of_foos);
   *
   * @param The list to initialized.
   */
  static void
  list_init(struct list *list)
  {
      list->next = list->prev = list;
  }
  
  static inline void
  __list_add(struct list *entry,
                  struct list *prev, struct list *next)
  {
      next->prev = entry;
      entry->next = next;
      entry->prev = prev;
      prev->next = entry;
  }
  
  /**
   * Insert a new element after the given list head. The new element does not
   * need to be initialised as empty list.
   * The list changes from:
   *      head → some element → ...
   * to
   *      head → new element → older element → ...
   *
   * Example:
   * struct foo *newfoo = malloc(...);
   * list_add(&newfoo->entry, &bar->list_of_foos);
   *
   * @param entry The new element to prepend to the list.
   * @param head The existing list.
   */
  static inline void
  list_add(struct list *entry, struct list *head)
  {
      __list_add(entry, head, head->next);
  }
  
  /**
   * Append a new element to the end of the list given with this list head.
   *
   * The list changes from:
   *      head → some element → ... → lastelement
   * to
   *      head → some element → ... → lastelement → new element
   *
   * Example:
   * struct foo *newfoo = malloc(...);
   * list_append(&newfoo->entry, &bar->list_of_foos);
   *
   * @param entry The new element to prepend to the list.
   * @param head The existing list.
   */
  static inline void
  list_append(struct list *entry, struct list *head)
  {
      __list_add(entry, head->prev, head);
  }
  
  static inline void
  __list_del(struct list *prev, struct list *next)
  {
      next->prev = prev;
      prev->next = next;
  }
  
  /**
   * Remove the element from the list it is in. Using this function will reset
   * the pointers to/from this element so it is removed from the list. It does
   * NOT free the element itself or manipulate it otherwise.
   *
   * Using list_del on a pure list head (like in the example at the top of
   * this file) will NOT remove the first element from
   * the list but rather reset the list as empty list.
   *
   * Example:
   * list_del(&foo->entry);
   *
   * @param entry The element to remove.
   */
  static inline void
  list_del(struct list *entry)
  {
      __list_del(entry->prev, entry->next);
      list_init(entry);
  }
  
  /**
   * Check if the list is empty.
   *
   * Example:
   * list_empty(&bar->list_of_foos);
   *
   * @return True if the list contains one or more elements or False otherwise.
   */
  static inline bool
  list_empty(struct list *head)
  {
      return head->next == head;
  }
  
  /**
   * Replace a list element by another one. This can also be used to replace
   * the head of an existing list by another list head.
   *
   * Example:
   * list_replace(&object_foo->entry, &object_bar->entry);
   * list_replace(&from->list_head, &into->list_head);
   *
   * @param old The element being replaced.
   * @param new The element to replace @old with.
   */
  static inline void
  list_replace(struct list *old, struct list *new)
  {
      new->next = old->next;
      new->next->prev = new;
      new->prev = old->prev;
      new->prev->next = new;
  }
  
  /**
   * Returns a pointer to the container of this list element.
   *
   * Example:
   * struct foo* f;
   * f = container_of(&foo->entry, struct foo, entry);
   * assert(f == foo);
   *
   * @param ptr Pointer to the struct list.
   * @param type Data type of the list element.
   * @param member Member name of the struct list field in the list element.
   * @return A pointer to the data struct containing the list head.
   */
  #ifndef container_of
  #define container_of(ptr, type, member) \
      (type *)((char *)(ptr) - (char *) &((type *)0)->member)
  #endif
  
  /**
   * Alias of container_of
   */
  #define list_entry(ptr, type, member) \
      container_of(ptr, type, member)
  
  /**
   * Retrieve the first list entry for the given list pointer.
   *
   * Example:
   * struct foo *first;
   * first = list_first_entry(&bar->list_of_foos, struct foo, list_of_foos);
   *
   * @param ptr The list head
   * @param type Data type of the list element to retrieve
   * @param member Member name of the struct list field in the list element.
   * @return A pointer to the first list element.
   */
  #define list_first_entry(ptr, type, member) \
      list_entry((ptr)->next, type, member)
  
  /**
   * Retrieve the last list entry for the given listpointer.
   *
   * Example:
   * struct foo *first;
   * first = list_last_entry(&bar->list_of_foos, struct foo, list_of_foos);
   *
   * @param ptr The list head
   * @param type Data type of the list element to retrieve
   * @param member Member name of the struct list field in the list element.
   * @return A pointer to the last list element.
   */
  #define list_last_entry(ptr, type, member) \
      list_entry((ptr)->prev, type, member)
  
  #define __container_of(ptr, sample, member)				\
      (void *)((char *)(ptr)						\
  	     - offsetof(__typeof(*sample), member))
  /**
   * Loop through the list given by head and set pos to struct in the list.
   *
   * Example:
   * struct foo *iterator;
   * list_foreach(iterator, &bar->list_of_foos, entry) {
   *      [modify iterator]
   * }
   *
   * This macro is not safe for node deletion. Use list_foreach_safe
   * instead.
   *
   * @param pos Iterator variable of the type of the list elements.
   * @param head List head
   * @param member Member name of the struct list in the list elements.
   *
   */
  #define list_foreach(pos, head, member)				        \
      for (pos = __container_of((head)->next, pos, member);		\
  	 &pos->member != (head);					\
  	 pos = __container_of(pos->member.next, pos, member))
  
  /**
   * Loop through the list, keeping a backup pointer to the element. This
   * macro allows for the deletion of a list element while looping through the
   * list.
   *
   * See list_foreach for more details.
   */
  #define list_foreach_safe(pos, tmp, head, member)		        \
      for (pos = __container_of((head)->next, pos, member),		\
  	 tmp = __container_of(pos->member.next, pos, member);		\
  	 &pos->member != (head);					\
  	 pos = tmp, tmp = __container_of(pos->member.next, tmp, member))
  
  /* NULL-Terminated List Interface
   *
   * The interface below does _not_ use the struct list as described above.
   * It is mainly for legacy structures that cannot easily be switched to
   * struct list.
   *
   * This interface is for structs like
   *      struct foo {
   *          [...]
   *          struct foo *next;
   *           [...]
   *      };
   *
   * The position and field name of "next" are arbitrary.
   */
  
  /**
   * Init the element as null-terminated list.
   *
   * Example:
   * struct foo *list = malloc();
   * nt_list_init(list, next);
   *
   * @param list The list element that will be the start of the list
   * @param member Member name of the field pointing to next struct
   */
  #define nt_list_init(_list, _member) \
  	(_list)->_member = NULL
  
  /**
   * Returns the next element in the list or NULL on termination.
   *
   * Example:
   * struct foo *element = list;
   * while ((element = nt_list_next(element, next)) { }
   *
   * This macro is not safe for node deletion. Use list_foreach_safe
   * instead.
   *
   * @param list The list or current element.
   * @param member Member name of the field pointing to next struct.
   */
  #define nt_list_next(_list, _member) \
  	(_list)->_member
  
  /**
   * Iterate through each element in the list.
   *
   * Example:
   * struct foo *iterator;
   * nt_list_foreach(iterator, list, next) {
   *      [modify iterator]
   * }
   *
   * @param entry Assigned to the current list element
   * @param list The list to iterate through.
   * @param member Member name of the field pointing to next struct.
   */
  #define nt_list_foreach(_entry, _list, _member)			\
  	for (_entry = _list; _entry; _entry = (_entry)->_member)
  
  /**
   * Iterate through each element in the list, keeping a backup pointer to the
   * element. This macro allows for the deletion of a list element while
   * looping through the list.
   *
   * See nt_list_foreach for more details.
   *
   * @param entry Assigned to the current list element
   * @param tmp The pointer to the next element
   * @param list The list to iterate through.
   * @param member Member name of the field pointing to next struct.
   */
  #define nt_list_foreach_safe(_entry, _tmp, _list, _member)	\
  	for (_entry = _list, _tmp = (_entry) ? (_entry)->_member : NULL;\
  		_entry;							\
  		_entry = _tmp, _tmp = (_tmp) ? (_tmp)->_member: NULL)
  
  /**
   * Append the element to the end of the list. This macro may be used to
   * merge two lists.
   *
   * Example:
   * struct foo *elem = malloc(...);
   * nt_list_init(elem, next)
   * nt_list_append(elem, list, struct foo, next);
   *
   * Resulting list order:
   * list_item_0 -> list_item_1 -> ... -> elem_item_0 -> elem_item_1 ...
   *
   * @param entry An entry (or list) to append to the list
   * @param list The list to append to. This list must be a valid list, not
   * NULL.
   * @param type The list type
   * @param member Member name of the field pointing to next struct
   */
  #define nt_list_append(_entry, _list, _type, _member)		        \
      do {								\
  	_type *__iterator = _list;					\
  	while (__iterator->_member) { __iterator = __iterator->_member;}\
  	__iterator->_member = _entry;					\
      } while (0)
  
  /**
   * Insert the element at the next position in the list. This macro may be
   * used to insert a list into a list.
   *
   * struct foo *elem = malloc(...);
   * nt_list_init(elem, next)
   * nt_list_insert(elem, list, struct foo, next);
   *
   * Resulting list order:
   * list_item_0 -> elem_item_0 -> elem_item_1 ... -> list_item_1 -> ...
   *
   * @param entry An entry (or list) to append to the list
   * @param list The list to insert to. This list must be a valid list, not
   * NULL.
   * @param type The list type
   * @param member Member name of the field pointing to next struct
   */
  #define nt_list_insert(_entry, _list, _type, _member)			\
      do {								\
  	nt_list_append((_list)->_member, _entry, _type, _member);	\
  	(_list)->_member = _entry;					\
      } while (0)
  
  /**
   * Delete the entry from the list by iterating through the list and
   * removing any reference from the list to the entry.
   *
   * Example:
   * struct foo *elem = <assign to right element>
   * nt_list_del(elem, list, struct foo, next);
   *
   * @param entry The entry to delete from the list. entry is always
   * re-initialized as a null-terminated list.
   * @param list The list containing the entry, set to the new list without
   * the removed entry.
   * @param type The list type
   * @param member Member name of the field pointing to the next entry
   */
  #define nt_list_del(_entry, _list, _type, _member)		\
  	do {							\
  		_type *__e = _entry;				\
  		if (__e == NULL || _list == NULL) break;        \
  		if ((_list) == __e) {				\
  		    _list = __e->_member;			\
  		} else {					\
  		    _type *__prev = _list;			\
  		    while (__prev->_member && __prev->_member != __e)	\
  			__prev = nt_list_next(__prev, _member);	\
  		    if (__prev->_member)			\
  			__prev->_member = __e->_member;		\
  		}						\
  		nt_list_init(__e, _member);			\
  	} while(0)
  
  #endif