/* * Asterisk -- An open source telephony toolkit. * * Copyright (C) 1999 - 2006, Digium, Inc. * * Mark Spencer * Kevin P. Fleming * * See http://www.asterisk.org for more information about * the Asterisk project. Please do not directly contact * any of the maintainers of this project for assistance; * the project provides a web site, mailing lists and IRC * channels for your use. * * This program is free software, distributed under the terms of * the GNU General Public License Version 2. See the LICENSE file * at the top of the source tree. */ #ifndef ASTERISK_LINKEDLISTS_H #define ASTERISK_LINKEDLISTS_H #include "asterisk/lock.h" /*! * \file linkedlists.h * \brief A set of macros to manage forward-linked lists. */ /*! * \brief Locks a list. * \param head This is a pointer to the list head structure * * This macro attempts to place an exclusive lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_LIST_LOCK(head) \ ast_mutex_lock(&(head)->lock) /*! * \brief Write locks a list. * \param head This is a pointer to the list head structure * * This macro attempts to place an exclusive write lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_RWLIST_WRLOCK(head) \ ast_rwlock_wrlock(&(head)->lock) /*! * \brief Write locks a list, with timeout. * \param head This is a pointer to the list head structure * \param ts Pointer to a timespec structure * * This macro attempts to place an exclusive write lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure * * \since 1.6.1 */ #define AST_RWLIST_TIMEDWRLOCK(head, ts) ast_rwlock_timedwrlock(&(head)->lock, ts) /*! * \brief Read locks a list. * \param head This is a pointer to the list head structure * * This macro attempts to place a read lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_RWLIST_RDLOCK(head) \ ast_rwlock_rdlock(&(head)->lock) /*! * \brief Read locks a list, with timeout. * \param head This is a pointer to the list head structure * \param ts Pointer to a timespec structure * * This macro attempts to place a read lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure * * \since 1.6.1 */ #define AST_RWLIST_TIMEDRDLOCK(head, ts) \ ast_rwlock_timedrdlock(&(head)->lock, ts) /*! * \brief Locks a list, without blocking if the list is locked. * \param head This is a pointer to the list head structure * * This macro attempts to place an exclusive lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_LIST_TRYLOCK(head) \ ast_mutex_trylock(&(head)->lock) /*! * \brief Write locks a list, without blocking if the list is locked. * \param head This is a pointer to the list head structure * * This macro attempts to place an exclusive write lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_RWLIST_TRYWRLOCK(head) \ ast_rwlock_trywrlock(&(head)->lock) /*! * \brief Read locks a list, without blocking if the list is locked. * \param head This is a pointer to the list head structure * * This macro attempts to place a read lock in the * list head structure pointed to by head. * \retval 0 on success * \retval non-zero on failure */ #define AST_RWLIST_TRYRDLOCK(head) \ ast_rwlock_tryrdlock(&(head)->lock) /*! * \brief Attempts to unlock a list. * \param head This is a pointer to the list head structure * * This macro attempts to remove an exclusive lock from the * list head structure pointed to by head. If the list * was not locked by this thread, this macro has no effect. */ #define AST_LIST_UNLOCK(head) \ ast_mutex_unlock(&(head)->lock) /*! * \brief Attempts to unlock a read/write based list. * \param head This is a pointer to the list head structure * * This macro attempts to remove a read or write lock from the * list head structure pointed to by head. If the list * was not locked by this thread, this macro has no effect. */ #define AST_RWLIST_UNLOCK(head) \ ast_rwlock_unlock(&(head)->lock) /*! * \brief Defines a structure to be used to hold a list of specified type. * \param name This will be the name of the defined structure. * \param type This is the type of each list entry. * * This macro creates a structure definition that can be used * to hold a list of the entries of type \a type. It does not actually * declare (allocate) a structure; to do that, either follow this * macro with the desired name of the instance you wish to declare, * or use the specified \a name to declare instances elsewhere. * * Example usage: * \code * static AST_LIST_HEAD(entry_list, entry) entries; * \endcode * * This would define \c struct \c entry_list, and declare an instance of it named * \a entries, all intended to hold a list of type \c struct \c entry. */ #define AST_LIST_HEAD(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_mutex_t lock; \ } /*! * \brief Defines a structure to be used to hold a read/write list of specified type. * \param name This will be the name of the defined structure. * \param type This is the type of each list entry. * * This macro creates a structure definition that can be used * to hold a list of the entries of type \a type. It does not actually * declare (allocate) a structure; to do that, either follow this * macro with the desired name of the instance you wish to declare, * or use the specified \a name to declare instances elsewhere. * * Example usage: * \code * static AST_RWLIST_HEAD(entry_list, entry) entries; * \endcode * * This would define \c struct \c entry_list, and declare an instance of it named * \a entries, all intended to hold a list of type \c struct \c entry. */ #define AST_RWLIST_HEAD(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_rwlock_t lock; \ } /*! * \brief Defines a structure to be used to hold a list of specified type (with no lock). * \param name This will be the name of the defined structure. * \param type This is the type of each list entry. * * This macro creates a structure definition that can be used * to hold a list of the entries of type \a type. It does not actually * declare (allocate) a structure; to do that, either follow this * macro with the desired name of the instance you wish to declare, * or use the specified \a name to declare instances elsewhere. * * Example usage: * \code * static AST_LIST_HEAD_NOLOCK(entry_list, entry) entries; * \endcode * * This would define \c struct \c entry_list, and declare an instance of it named * \a entries, all intended to hold a list of type \c struct \c entry. */ #define AST_LIST_HEAD_NOLOCK(name, type) \ struct name { \ struct type *first; \ struct type *last; \ } /*! * \brief Defines initial values for a declaration of AST_LIST_HEAD */ #define AST_LIST_HEAD_INIT_VALUE { \ .first = NULL, \ .last = NULL, \ .lock = AST_MUTEX_INIT_VALUE, \ } /*! * \brief Defines initial values for a declaration of AST_RWLIST_HEAD */ #define AST_RWLIST_HEAD_INIT_VALUE { \ .first = NULL, \ .last = NULL, \ .lock = AST_RWLOCK_INIT_VALUE, \ } /*! * \brief Defines initial values for a declaration of AST_LIST_HEAD_NOLOCK */ #define AST_LIST_HEAD_NOLOCK_INIT_VALUE { \ .first = NULL, \ .last = NULL, \ } /*! * \brief Defines a structure to be used to hold a list of specified type, statically initialized. * \param name This will be the name of the defined structure. * \param type This is the type of each list entry. * * This macro creates a structure definition that can be used * to hold a list of the entries of type \a type, and allocates an instance * of it, initialized to be empty. * * Example usage: * \code * static AST_LIST_HEAD_STATIC(entry_list, entry); * \endcode * * This would define \c struct \c entry_list, intended to hold a list of * type \c struct \c entry. */ #if defined(AST_MUTEX_INIT_W_CONSTRUCTORS) #define AST_LIST_HEAD_STATIC(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_mutex_t lock; \ } name; \ static void __attribute__((constructor)) __init_##name(void) \ { \ AST_LIST_HEAD_INIT(&name); \ } \ static void __attribute__((destructor)) __fini_##name(void) \ { \ AST_LIST_HEAD_DESTROY(&name); \ } \ struct __dummy_##name #else #define AST_LIST_HEAD_STATIC(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_mutex_t lock; \ } name = AST_LIST_HEAD_INIT_VALUE #endif /*! * \brief Defines a structure to be used to hold a read/write list of specified type, statically initialized. * \param name This will be the name of the defined structure. * \param type This is the type of each list entry. * * This macro creates a structure definition that can be used * to hold a list of the entries of type \a type, and allocates an instance * of it, initialized to be empty. * * Example usage: * \code * static AST_RWLIST_HEAD_STATIC(entry_list, entry); * \endcode * * This would define \c struct \c entry_list, intended to hold a list of * type \c struct \c entry. */ #ifndef HAVE_PTHREAD_RWLOCK_INITIALIZER #define AST_RWLIST_HEAD_STATIC(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_rwlock_t lock; \ } name; \ static void __attribute__((constructor)) __init_##name(void) \ { \ AST_RWLIST_HEAD_INIT(&name); \ } \ static void __attribute__((destructor)) __fini_##name(void) \ { \ AST_RWLIST_HEAD_DESTROY(&name); \ } \ struct __dummy_##name #else #define AST_RWLIST_HEAD_STATIC(name, type) \ struct name { \ struct type *first; \ struct type *last; \ ast_rwlock_t lock; \ } name = AST_RWLIST_HEAD_INIT_VALUE #endif /*! * \brief Defines a structure to be used to hold a list of specified type, statically initialized. * * This is the same as AST_LIST_HEAD_STATIC, except without the lock included. */ #define AST_LIST_HEAD_NOLOCK_STATIC(name, type) \ struct name { \ struct type *first; \ struct type *last; \ } name = AST_LIST_HEAD_NOLOCK_INIT_VALUE /*! * \brief Initializes a list head structure with a specified first entry. * \param head This is a pointer to the list head structure * \param entry pointer to the list entry that will become the head of the list * * This macro initializes a list head structure by setting the head * entry to the supplied value and recreating the embedded lock. */ #define AST_LIST_HEAD_SET(head, entry) do { \ (head)->first = (entry); \ (head)->last = (entry); \ ast_mutex_init(&(head)->lock); \ } while (0) /*! * \brief Initializes an rwlist head structure with a specified first entry. * \param head This is a pointer to the list head structure * \param entry pointer to the list entry that will become the head of the list * * This macro initializes a list head structure by setting the head * entry to the supplied value and recreating the embedded lock. */ #define AST_RWLIST_HEAD_SET(head, entry) do { \ (head)->first = (entry); \ (head)->last = (entry); \ ast_rwlock_init(&(head)->lock); \ } while (0) /*! * \brief Initializes a list head structure with a specified first entry. * \param head This is a pointer to the list head structure * \param entry pointer to the list entry that will become the head of the list * * This macro initializes a list head structure by setting the head * entry to the supplied value. */ #define AST_LIST_HEAD_SET_NOLOCK(head, entry) do { \ (head)->first = (entry); \ (head)->last = (entry); \ } while (0) /*! * \brief Declare a forward link structure inside a list entry. * \param type This is the type of each list entry. * * This macro declares a structure to be used to link list entries together. * It must be used inside the definition of the structure named in * \a type, as follows: * * \code * struct list_entry { ... AST_LIST_ENTRY(list_entry) list; * } * \endcode * * The field name \a list here is arbitrary, and can be anything you wish. */ #define AST_LIST_ENTRY(type) \ struct { \ struct type *next; \ } #define AST_RWLIST_ENTRY AST_LIST_ENTRY /*! * \brief Returns the first entry contained in a list. * \param head This is a pointer to the list head structure */ #define AST_LIST_FIRST(head) ((head)->first) #define AST_RWLIST_FIRST AST_LIST_FIRST /*! * \brief Returns the last entry contained in a list. * \param head This is a pointer to the list head structure */ #define AST_LIST_LAST(head) ((head)->last) #define AST_RWLIST_LAST AST_LIST_LAST /*! * \brief Returns the next entry in the list after the given entry. * \param elm This is a pointer to the current entry. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. */ #define AST_LIST_NEXT(elm, field) ((elm)->field.next) #define AST_RWLIST_NEXT AST_LIST_NEXT /*! * \brief Checks whether the specified list contains any entries. * \param head This is a pointer to the list head structure * * \return zero if the list has entries * \return non-zero if not. */ #define AST_LIST_EMPTY(head) (AST_LIST_FIRST(head) == NULL) #define AST_RWLIST_EMPTY AST_LIST_EMPTY /*! * \brief Loops over (traverses) the entries in a list. * \param head This is a pointer to the list head structure * \param var This is the name of the variable that will hold a pointer to the * current list entry on each iteration. It must be declared before calling * this macro. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * This macro is use to loop over (traverse) the entries in a list. It uses a * \a for loop, and supplies the enclosed code with a pointer to each list * entry as it loops. It is typically used as follows: * \code * static AST_LIST_HEAD(entry_list, list_entry) entries; * ... * struct list_entry { ... AST_LIST_ENTRY(list_entry) list; * } * ... * struct list_entry *current; * ... * AST_LIST_TRAVERSE(&entries, current, list) { (do something with current here) * } * \endcode * \warning If you modify the forward-link pointer contained in the \a current entry while * inside the loop, the behavior will be unpredictable. At a minimum, the following * macros will modify the forward-link pointer, and should not be used inside * AST_LIST_TRAVERSE() against the entry pointed to by the \a current pointer without * careful consideration of their consequences: * \li AST_LIST_NEXT() (when used as an lvalue) * \li AST_LIST_INSERT_AFTER() * \li AST_LIST_INSERT_HEAD() * \li AST_LIST_INSERT_TAIL() * \li AST_LIST_INSERT_SORTALPHA() */ #define AST_LIST_TRAVERSE(head,var,field) \ for((var) = (head)->first; (var); (var) = (var)->field.next) #define AST_RWLIST_TRAVERSE AST_LIST_TRAVERSE /*! * \brief Loops safely over (traverses) the entries in a list. * \param head This is a pointer to the list head structure * \param var This is the name of the variable that will hold a pointer to the * current list entry on each iteration. It must be declared before calling * this macro. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * This macro is used to safely loop over (traverse) the entries in a list. It * uses a \a for loop, and supplies the enclosed code with a pointer to each list * entry as it loops. It is typically used as follows: * * \code * static AST_LIST_HEAD(entry_list, list_entry) entries; * ... * struct list_entry { ... AST_LIST_ENTRY(list_entry) list; * } * ... * struct list_entry *current; * ... * AST_LIST_TRAVERSE_SAFE_BEGIN(&entries, current, list) { (do something with current here) * } * AST_LIST_TRAVERSE_SAFE_END; * \endcode * * It differs from AST_LIST_TRAVERSE() in that the code inside the loop can modify * (or even free, after calling AST_LIST_REMOVE_CURRENT()) the entry pointed to by * the \a current pointer without affecting the loop traversal. */ #define AST_LIST_TRAVERSE_SAFE_BEGIN(head, var, field) { \ typeof((head)) __list_head = head; \ typeof(__list_head->first) __list_next; \ typeof(__list_head->first) __list_prev = NULL; \ typeof(__list_head->first) __new_prev = NULL; \ for ((var) = __list_head->first, __new_prev = (var), \ __list_next = (var) ? (var)->field.next : NULL; \ (var); \ __list_prev = __new_prev, (var) = __list_next, \ __new_prev = (var), \ __list_next = (var) ? (var)->field.next : NULL \ ) #define AST_RWLIST_TRAVERSE_SAFE_BEGIN AST_LIST_TRAVERSE_SAFE_BEGIN /*! * \brief Removes the \a current entry from a list during a traversal. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * \note This macro can \b only be used inside an AST_LIST_TRAVERSE_SAFE_BEGIN() * block; it is used to unlink the current entry from the list without affecting * the list traversal (and without having to re-traverse the list to modify the * previous entry, if any). */ #define AST_LIST_REMOVE_CURRENT(field) do { \ __new_prev->field.next = NULL; \ __new_prev = __list_prev; \ if (__list_prev) \ __list_prev->field.next = __list_next; \ else \ __list_head->first = __list_next; \ if (!__list_next) \ __list_head->last = __list_prev; \ } while (0) #define AST_RWLIST_REMOVE_CURRENT AST_LIST_REMOVE_CURRENT #define AST_LIST_MOVE_CURRENT(newhead, field) do { \ typeof ((newhead)->first) __list_cur = __new_prev; \ AST_LIST_REMOVE_CURRENT(field); \ AST_LIST_INSERT_TAIL((newhead), __list_cur, field); \ } while (0) #define AST_RWLIST_MOVE_CURRENT AST_LIST_MOVE_CURRENT /*! * \brief Inserts a list entry before the current entry during a traversal. * \param elm This is a pointer to the entry to be inserted. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * \note This macro can \b only be used inside an AST_LIST_TRAVERSE_SAFE_BEGIN() * block. */ #define AST_LIST_INSERT_BEFORE_CURRENT(elm, field) do { \ if (__list_prev) { \ (elm)->field.next = __list_prev->field.next; \ __list_prev->field.next = elm; \ } else { \ (elm)->field.next = __list_head->first; \ __list_head->first = (elm); \ } \ __new_prev = (elm); \ } while (0) #define AST_RWLIST_INSERT_BEFORE_CURRENT AST_LIST_INSERT_BEFORE_CURRENT /*! * \brief Closes a safe loop traversal block. */ #define AST_LIST_TRAVERSE_SAFE_END } #define AST_RWLIST_TRAVERSE_SAFE_END AST_LIST_TRAVERSE_SAFE_END /*! * \brief Initializes a list head structure. * \param head This is a pointer to the list head structure * * This macro initializes a list head structure by setting the head * entry to \a NULL (empty list) and recreating the embedded lock. */ #define AST_LIST_HEAD_INIT(head) { \ (head)->first = NULL; \ (head)->last = NULL; \ ast_mutex_init(&(head)->lock); \ } /*! * \brief Initializes an rwlist head structure. * \param head This is a pointer to the list head structure * * This macro initializes a list head structure by setting the head * entry to \a NULL (empty list) and recreating the embedded lock. */ #define AST_RWLIST_HEAD_INIT(head) { \ (head)->first = NULL; \ (head)->last = NULL; \ ast_rwlock_init(&(head)->lock); \ } /*! * \brief Destroys a list head structure. * \param head This is a pointer to the list head structure * * This macro destroys a list head structure by setting the head * entry to \a NULL (empty list) and destroying the embedded lock. * It does not free the structure from memory. */ #define AST_LIST_HEAD_DESTROY(head) { \ (head)->first = NULL; \ (head)->last = NULL; \ ast_mutex_destroy(&(head)->lock); \ } /*! * \brief Destroys an rwlist head structure. * \param head This is a pointer to the list head structure * * This macro destroys a list head structure by setting the head * entry to \a NULL (empty list) and destroying the embedded lock. * It does not free the structure from memory. */ #define AST_RWLIST_HEAD_DESTROY(head) { \ (head)->first = NULL; \ (head)->last = NULL; \ ast_rwlock_destroy(&(head)->lock); \ } /*! * \brief Initializes a list head structure. * \param head This is a pointer to the list head structure * * This macro initializes a list head structure by setting the head * entry to \a NULL (empty list). There is no embedded lock handling * with this macro. */ #define AST_LIST_HEAD_INIT_NOLOCK(head) { \ (head)->first = NULL; \ (head)->last = NULL; \ } /*! * \brief Inserts a list entry after a given entry. * \param head This is a pointer to the list head structure * \param listelm This is a pointer to the entry after which the new entry should * be inserted. * \param elm This is a pointer to the entry to be inserted. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. */ #define AST_LIST_INSERT_AFTER(head, listelm, elm, field) do { \ (elm)->field.next = (listelm)->field.next; \ (listelm)->field.next = (elm); \ if ((head)->last == (listelm)) \ (head)->last = (elm); \ } while (0) #define AST_RWLIST_INSERT_AFTER AST_LIST_INSERT_AFTER /*! * \brief Inserts a list entry at the head of a list. * \param head This is a pointer to the list head structure * \param elm This is a pointer to the entry to be inserted. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. */ #define AST_LIST_INSERT_HEAD(head, elm, field) do { \ (elm)->field.next = (head)->first; \ (head)->first = (elm); \ if (!(head)->last) \ (head)->last = (elm); \ } while (0) #define AST_RWLIST_INSERT_HEAD AST_LIST_INSERT_HEAD /*! * \brief Appends a list entry to the tail of a list. * \param head This is a pointer to the list head structure * \param elm This is a pointer to the entry to be appended. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * Note: The link field in the appended entry is \b not modified, so if it is * actually the head of a list itself, the entire list will be appended * temporarily (until the next AST_LIST_INSERT_TAIL is performed). */ #define AST_LIST_INSERT_TAIL(head, elm, field) do { \ if (!(head)->first) { \ (head)->first = (elm); \ (head)->last = (elm); \ } else { \ (head)->last->field.next = (elm); \ (head)->last = (elm); \ } \ } while (0) #define AST_RWLIST_INSERT_TAIL AST_LIST_INSERT_TAIL /*! * \brief Inserts a list entry into a alphabetically sorted list * \param head Pointer to the list head structure * \param elm Pointer to the entry to be inserted * \param field Name of the list entry field (declared using AST_LIST_ENTRY()) * \param sortfield Name of the field on which the list is sorted * \since 1.6.1 */ #define AST_LIST_INSERT_SORTALPHA(head, elm, field, sortfield) do { \ if (!(head)->first) { \ (head)->first = (elm); \ (head)->last = (elm); \ } else { \ typeof((head)->first) cur = (head)->first, prev = NULL; \ while (cur && strcmp(cur->sortfield, elm->sortfield) < 0) { \ prev = cur; \ cur = cur->field.next; \ } \ if (!prev) { \ AST_LIST_INSERT_HEAD(head, elm, field); \ } else if (!cur) { \ AST_LIST_INSERT_TAIL(head, elm, field); \ } else { \ AST_LIST_INSERT_AFTER(head, prev, elm, field); \ } \ } \ } while (0) #define AST_RWLIST_INSERT_SORTALPHA AST_LIST_INSERT_SORTALPHA /*! * \brief Appends a whole list to the tail of a list. * \param head This is a pointer to the list head structure * \param list This is a pointer to the list to be appended. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * Note: The source list (the \a list parameter) will be empty after * calling this macro (the list entries are \b moved to the target list). */ #define AST_LIST_APPEND_LIST(head, list, field) do { \ if (!(list)->first) { \ break; \ } \ if (!(head)->first) { \ (head)->first = (list)->first; \ (head)->last = (list)->last; \ } else { \ (head)->last->field.next = (list)->first; \ (head)->last = (list)->last; \ } \ (list)->first = NULL; \ (list)->last = NULL; \ } while (0) #define AST_RWLIST_APPEND_LIST AST_LIST_APPEND_LIST /*! \brief Inserts a whole list after a specific entry in a list \param head This is a pointer to the list head structure \param list This is a pointer to the list to be inserted. \param elm This is a pointer to the entry after which the new list should be inserted. \param field This is the name of the field (declared using AST_LIST_ENTRY()) used to link entries of the lists together. Note: The source list (the \a list parameter) will be empty after calling this macro (the list entries are \b moved to the target list). */ #define AST_LIST_INSERT_LIST_AFTER(head, list, elm, field) do { \ (list)->last->field.next = (elm)->field.next; \ (elm)->field.next = (list)->first; \ if ((head)->last == elm) { \ (head)->last = (list)->last; \ } \ (list)->first = NULL; \ (list)->last = NULL; \ } while(0) #define AST_RWLIST_INSERT_LIST_AFTER AST_LIST_INSERT_LIST_AFTER /*! * \brief Removes and returns the head entry from a list. * \param head This is a pointer to the list head structure * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * * Removes the head entry from the list, and returns a pointer to it. * This macro is safe to call on an empty list. */ #define AST_LIST_REMOVE_HEAD(head, field) ({ \ typeof((head)->first) cur = (head)->first; \ if (cur) { \ (head)->first = cur->field.next; \ cur->field.next = NULL; \ if ((head)->last == cur) \ (head)->last = NULL; \ } \ cur; \ }) #define AST_RWLIST_REMOVE_HEAD AST_LIST_REMOVE_HEAD /*! * \brief Removes a specific entry from a list. * \param head This is a pointer to the list head structure * \param elm This is a pointer to the entry to be removed. * \param field This is the name of the field (declared using AST_LIST_ENTRY()) * used to link entries of this list together. * \warning The removed entry is \b not freed nor modified in any way. */ #define AST_LIST_REMOVE(head, elm, field) ({ \ __typeof(elm) __res = NULL; \ if ((head)->first == (elm)) { \ __res = (head)->first; \ (head)->first = (elm)->field.next; \ if ((head)->last == (elm)) \ (head)->last = NULL; \ } else { \ typeof(elm) curelm = (head)->first; \ while (curelm && (curelm->field.next != (elm))) \ curelm = curelm->field.next; \ if (curelm) { \ __res = (elm); \ curelm->field.next = (elm)->field.next; \ if ((head)->last == (elm)) \ (head)->last = curelm; \ } \ } \ (elm)->field.next = NULL; \ (__res); \ }) #define AST_RWLIST_REMOVE AST_LIST_REMOVE #endif /* _ASTERISK_LINKEDLISTS_H */