Add glvnd_list.h

This is a copy of list.h from xserver commit
74469895e39fa38337f59edd64c4031ab9bb51d8, modified to prevent namespace
clashes with list.h.

1 files changed, 482 insertions, 0 deletions

diff --git a/include/glvnd_list.h b/include/glvnd_list.h
new file mode 100644
index 0000000..60700e9
--- /dev/null
+++ b/include/glvnd_list.h
@@ -0,0 +1,482 @@
+/*
+ * 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 _GLVND_LIST_H_
+#define _GLVND_LIST_H_
+
+#include <stddef.h> /* offsetof() */
+
+/**
+ * @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 glvnd_list').
+ *
+ *     struct bar {
+ *          ...
+ *          struct glvnd_list list_of_foos;
+ *          ...
+ *     }
+ *
+ *     struct foo {
+ *          ...
+ *          struct glvnd_list entry;
+ *          ...
+ *     }
+ *
+ * Now we initialize the list head:
+ *
+ *     struct bar bar;
+ *     ...
+ *     glvnd_list_init(&bar.list_of_foos);
+ *
+ * Then we create the first element and add it to this list:
+ *
+ *     struct foo *foo = malloc(...);
+ *     ....
+ *     glvnd_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.
+ *      glvnd_list_del(&foo->entry);
+ *      free(foo);
+ *
+ * Note: calling glvnd_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;
+ * glvnd_list_for_each_entry(iterator, &bar.list_of_foos, entry) {
+ *      if (iterator->something == ...)
+ *             ...
+ * }
+ *
+ * Note: You must not call glvnd_list_del() on the iterator if you continue the
+ * loop. You need to run the safe for-each loop instead:
+ *
+ * struct foo *iterator, *next;
+ * glvnd_list_for_each_entry_safe(iterator, next, &bar.list_of_foos, entry) {
+ *      if (...)
+ *              glvnd_list_del(&iterator->entry);
+ * }
+ *
+ */
+
+/**
+ * The linkage struct for list nodes. This struct must be part of your
+ * to-be-linked struct. struct glvnd_list is required for both the head of the
+ * list and for each list node.
+ *
+ * Position and name of the struct glvnd_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 glvnd_list can be a list
+ * head.
+ */
+struct glvnd_list {
+    struct glvnd_list *next, *prev;
+};
+
+/**
+ * Initialize the list as an empty list.
+ *
+ * Example:
+ * glvnd_list_init(&bar->list_of_foos);
+ *
+ * @param The list to initialized.
+ */
+static inline void
+glvnd_list_init(struct glvnd_list *list)
+{
+    list->next = list->prev = list;
+}
+
+static inline void
+__glvnd_list_add(struct glvnd_list *entry,
+                struct glvnd_list *prev, struct glvnd_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(...);
+ * glvnd_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
+glvnd_list_add(struct glvnd_list *entry, struct glvnd_list *head)
+{
+    __glvnd_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(...);
+ * glvnd_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
+glvnd_list_append(struct glvnd_list *entry, struct glvnd_list *head)
+{
+    __glvnd_list_add(entry, head->prev, head);
+}
+
+static inline void
+__glvnd_list_del(struct glvnd_list *prev, struct glvnd_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 glvnd_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:
+ * glvnd_list_del(&foo->entry);
+ *
+ * @param entry The element to remove.
+ */
+static inline void
+glvnd_list_del(struct glvnd_list *entry)
+{
+    __glvnd_list_del(entry->prev, entry->next);
+    glvnd_list_init(entry);
+}
+
+/**
+ * Check if the list is empty.
+ *
+ * Example:
+ * glvnd_list_is_empty(&bar->list_of_foos);
+ *
+ * @return True if the list contains one or more elements or False otherwise.
+ */
+static inline int
+glvnd_list_is_empty(struct glvnd_list *head)
+{
+    return head->next == head;
+}
+
+/**
+ * Returns a pointer to the container of this list element.
+ *
+ * Example:
+ * struct foo* f;
+ * f = glvnd_container_of(&foo->entry, struct foo, entry);
+ * assert(f == foo);
+ *
+ * @param ptr Pointer to the struct glvnd_list.
+ * @param type Data type of the list element.
+ * @param member Member name of the struct glvnd_list field in the list element.
+ * @return A pointer to the data struct containing the list head.
+ */
+#ifndef glvnd_container_of
+#define glvnd_container_of(ptr, type, member) \
+    (type *)((char *)(ptr) - offsetof(type, member))
+#endif
+
+/**
+ * Alias of glvnd_container_of
+ */
+#define glvnd_list_entry(ptr, type, member) \
+    glvnd_container_of(ptr, type, member)
+
+/**
+ * Retrieve the first list entry for the given list pointer.
+ *
+ * Example:
+ * struct foo *first;
+ * first = glvnd_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 glvnd_list field in the list element.
+ * @return A pointer to the first list element.
+ */
+#define glvnd_list_first_entry(ptr, type, member) \
+    glvnd_list_entry((ptr)->next, type, member)
+
+/**
+ * Retrieve the last list entry for the given listpointer.
+ *
+ * Example:
+ * struct foo *first;
+ * first = glvnd_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 glvnd_list field in the list element.
+ * @return A pointer to the last list element.
+ */
+#define glvnd_list_last_entry(ptr, type, member) \
+    glvnd_list_entry((ptr)->prev, type, member)
+
+#ifdef HAVE_TYPEOF
+#define __glvnd_container_of(ptr, sample, member)			\
+    glvnd_container_of(ptr, typeof(*sample), member)
+#else
+/* This implementation of __glvnd_container_of has undefined behavior according
+ * to the C standard, but it works in many cases.  If your compiler doesn't
+ * support typeof() and fails with this implementation, please try a newer
+ * compiler.
+ */
+#define __glvnd_container_of(ptr, sample, member)                            \
+    (void *)((char *)(ptr)                                             \
+            - ((char *)&(sample)->member - (char *)(sample)))
+#endif
+
+/**
+ * Loop through the list given by head and set pos to struct in the list.
+ *
+ * Example:
+ * struct foo *iterator;
+ * glvnd_list_for_each_entry(iterator, &bar->list_of_foos, entry) {
+ *      [modify iterator]
+ * }
+ *
+ * This macro is not safe for node deletion. Use glvnd_list_for_each_entry_safe
+ * instead.
+ *
+ * @param pos Iterator variable of the type of the list elements.
+ * @param head List head
+ * @param member Member name of the struct glvnd_list in the list elements.
+ *
+ */
+#define glvnd_list_for_each_entry(pos, head, member)				\
+    for (pos = __glvnd_container_of((head)->next, pos, member);		\
+	 &pos->member != (head);					\
+	 pos = __glvnd_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 glvnd_list_for_each_entry for more details.
+ */
+#define glvnd_list_for_each_entry_safe(pos, tmp, head, member)		\
+    for (pos = __glvnd_container_of((head)->next, pos, member),		\
+	 tmp = __glvnd_container_of(pos->member.next, pos, member);		\
+	 &pos->member != (head);					\
+	 pos = tmp, tmp = __glvnd_container_of(pos->member.next, tmp, member))
+
+/* NULL-Terminated List Interface
+ *
+ * The interface below does _not_ use the struct glvnd_list as described above.
+ * It is mainly for legacy structures that cannot easily be switched to
+ * struct glvnd_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();
+ * glvnd_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 glvnd_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 = glvnd_nt_list_next(element, next)) { }
+ *
+ * This macro is not safe for node deletion. Use glvnd_nt_list_for_each_entry_safe
+ * instead.
+ *
+ * @param list The list or current element.
+ * @param member Member name of the field pointing to next struct.
+ */
+#define glvnd_nt_list_next(_list, _member) \
+	(_list)->_member
+
+/**
+ * Iterate through each element in the list.
+ *
+ * Example:
+ * struct foo *iterator;
+ * glvnd_nt_list_for_each_entry(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 glvnd_nt_list_for_each_entry(_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 glvnd_nt_list_for_each_entry 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 glvnd_nt_list_for_each_entry_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(...);
+ * glvnd_nt_list_init(elem, next)
+ * glvnd_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 glvnd_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(...);
+ * glvnd_nt_list_init(elem, next)
+ * glvnd_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 glvnd_nt_list_insert(_entry, _list, _type, _member)			\
+    do {								\
+	glvnd_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>
+ * glvnd_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 glvnd_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 = glvnd_nt_list_next(__prev, _member);	\
+		    if (__prev->_member)			\
+			__prev->_member = __e->_member;		\
+		}						\
+		glvnd_nt_list_init(__e, _member);			\
+	} while(0)
+
+#endif