/* * Copyright © 2008, 2010 Intel Corporation * * 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. */ /** * \file list.h * \brief Doubly-linked list abstract container type. * * Each doubly-linked list has a sentinel head and tail node. These nodes * contain no data. The head sentinel can be identified by its \c prev * pointer being \c NULL. The tail sentinel can be identified by its * \c next pointer being \c NULL. * * A list is empty if either the head sentinel's \c next pointer points to the * tail sentinel or the tail sentinel's \c prev poiner points to the head * sentinel. * * Instead of tracking two separate \c node structures and a \c list structure * that points to them, the sentinel nodes are in a single structure. Noting * that each sentinel node always has one \c NULL pointer, the \c NULL * pointers occupy the same memory location. In the \c list structure * contains a the following: * * - A \c head pointer that represents the \c next pointer of the * head sentinel node. * - A \c tail pointer that represents the \c prev pointer of the head * sentinel node and the \c next pointer of the tail sentinel node. This * pointer is \b always \c NULL. * - A \c tail_prev pointer that represents the \c prev pointer of the * tail sentinel node. * * Therefore, if \c head->next is \c NULL or \c tail_prev->prev is \c NULL, * the list is empty. * * Do note that this means that the list nodes will contain pointers into the * list structure itself and as a result you may not \c realloc() an \c * exec_list or any structure in which an \c exec_list is embedded. * * To anyone familiar with "exec lists" on the Amiga, this structure should * be immediately recognizable. See the following link for the original Amiga * operating system documentation on the subject. * * http://www.natami.net/dev/Libraries_Manual_guide/node02D7.html * * \author Ian Romanick <ian.d.romanick@intel.com> */ #pragma once #ifndef LIST_CONTAINER_H #define LIST_CONTAINER_H #ifndef __cplusplus #include <stddef.h> #endif #include <assert.h> #include "util/ralloc.h" struct exec_node { struct exec_node *next; struct exec_node *prev; #ifdef __cplusplus DECLARE_RALLOC_CXX_OPERATORS(exec_node) exec_node() : next(NULL), prev(NULL) { /* empty */ } const exec_node *get_next() const; exec_node *get_next(); const exec_node *get_prev() const; exec_node *get_prev(); void remove(); /** * Link a node with itself * * This creates a sort of degenerate list that is occasionally useful. */ void self_link(); /** * Insert a node in the list after the current node */ void insert_after(exec_node *after); /** * Insert a node in the list before the current node */ void insert_before(exec_node *before); /** * Insert another list in the list before the current node */ void insert_before(struct exec_list *before); /** * Replace the current node with the given node. */ void replace_with(exec_node *replacement); /** * Is this the sentinel at the tail of the list? */ bool is_tail_sentinel() const; /** * Is this the sentinel at the head of the list? */ bool is_head_sentinel() const; #endif }; static inline void exec_node_init(struct exec_node *n) { n->next = NULL; n->prev = NULL; } static inline const struct exec_node * exec_node_get_next_const(const struct exec_node *n) { return n->next; } static inline struct exec_node * exec_node_get_next(struct exec_node *n) { return n->next; } static inline const struct exec_node * exec_node_get_prev_const(const struct exec_node *n) { return n->prev; } static inline struct exec_node * exec_node_get_prev(struct exec_node *n) { return n->prev; } static inline void exec_node_remove(struct exec_node *n) { n->next->prev = n->prev; n->prev->next = n->next; n->next = NULL; n->prev = NULL; } static inline void exec_node_self_link(struct exec_node *n) { n->next = n; n->prev = n; } static inline void exec_node_insert_after(struct exec_node *n, struct exec_node *after) { after->next = n->next; after->prev = n; n->next->prev = after; n->next = after; } static inline void exec_node_insert_node_before(struct exec_node *n, struct exec_node *before) { before->next = n; before->prev = n->prev; n->prev->next = before; n->prev = before; } static inline void exec_node_replace_with(struct exec_node *n, struct exec_node *replacement) { replacement->prev = n->prev; replacement->next = n->next; n->prev->next = replacement; n->next->prev = replacement; } static inline bool exec_node_is_tail_sentinel(const struct exec_node *n) { return n->next == NULL; } static inline bool exec_node_is_head_sentinel(const struct exec_node *n) { return n->prev == NULL; } #ifdef __cplusplus inline const exec_node *exec_node::get_next() const { return exec_node_get_next_const(this); } inline exec_node *exec_node::get_next() { return exec_node_get_next(this); } inline const exec_node *exec_node::get_prev() const { return exec_node_get_prev_const(this); } inline exec_node *exec_node::get_prev() { return exec_node_get_prev(this); } inline void exec_node::remove() { exec_node_remove(this); } inline void exec_node::self_link() { exec_node_self_link(this); } inline void exec_node::insert_after(exec_node *after) { exec_node_insert_after(this, after); } inline void exec_node::insert_before(exec_node *before) { exec_node_insert_node_before(this, before); } inline void exec_node::replace_with(exec_node *replacement) { exec_node_replace_with(this, replacement); } inline bool exec_node::is_tail_sentinel() const { return exec_node_is_tail_sentinel(this); } inline bool exec_node::is_head_sentinel() const { return exec_node_is_head_sentinel(this); } #endif #ifdef __cplusplus /* This macro will not work correctly if `t' uses virtual inheritance. If you * are using virtual inheritance, you deserve a slow and painful death. Enjoy! */ #define exec_list_offsetof(t, f, p) \ (((char *) &((t *) p)->f) - ((char *) p)) #else #define exec_list_offsetof(t, f, p) offsetof(t, f) #endif /** * Get a pointer to the structure containing an exec_node * * Given a pointer to an \c exec_node embedded in a structure, get a pointer to * the containing structure. * * \param type Base type of the structure containing the node * \param node Pointer to the \c exec_node * \param field Name of the field in \c type that is the embedded \c exec_node */ #define exec_node_data(type, node, field) \ ((type *) (((char *) node) - exec_list_offsetof(type, field, node))) #ifdef __cplusplus struct exec_node; #endif struct exec_list { struct exec_node *head; struct exec_node *tail; struct exec_node *tail_pred; #ifdef __cplusplus DECLARE_RALLOC_CXX_OPERATORS(exec_list) exec_list() { make_empty(); } void make_empty(); bool is_empty() const; const exec_node *get_head() const; exec_node *get_head(); const exec_node *get_tail() const; exec_node *get_tail(); unsigned length() const; void push_head(exec_node *n); void push_tail(exec_node *n); void push_degenerate_list_at_head(exec_node *n); /** * Remove the first node from a list and return it * * \return * The first node in the list or \c NULL if the list is empty. * * \sa exec_list::get_head */ exec_node *pop_head(); /** * Move all of the nodes from this list to the target list */ void move_nodes_to(exec_list *target); /** * Append all nodes from the source list to the end of the target list */ void append_list(exec_list *source); /** * Prepend all nodes from the source list to the beginning of the target * list */ void prepend_list(exec_list *source); #endif }; static inline void exec_list_make_empty(struct exec_list *list) { list->head = (struct exec_node *) & list->tail; list->tail = NULL; list->tail_pred = (struct exec_node *) & list->head; } static inline bool exec_list_is_empty(const struct exec_list *list) { /* There are three ways to test whether a list is empty or not. * * - Check to see if the \c head points to the \c tail. * - Check to see if the \c tail_pred points to the \c head. * - Check to see if the \c head is the sentinel node by test whether its * \c next pointer is \c NULL. * * The first two methods tend to generate better code on modern systems * because they save a pointer dereference. */ return list->head == (struct exec_node *) &list->tail; } static inline const struct exec_node * exec_list_get_head_const(const struct exec_list *list) { return !exec_list_is_empty(list) ? list->head : NULL; } static inline struct exec_node * exec_list_get_head(struct exec_list *list) { return !exec_list_is_empty(list) ? list->head : NULL; } static inline const struct exec_node * exec_list_get_tail_const(const struct exec_list *list) { return !exec_list_is_empty(list) ? list->tail_pred : NULL; } static inline struct exec_node * exec_list_get_tail(struct exec_list *list) { return !exec_list_is_empty(list) ? list->tail_pred : NULL; } static inline unsigned exec_list_length(const struct exec_list *list) { unsigned size = 0; struct exec_node *node; for (node = list->head; node->next != NULL; node = node->next) { size++; } return size; } static inline void exec_list_push_head(struct exec_list *list, struct exec_node *n) { n->next = list->head; n->prev = (struct exec_node *) &list->head; n->next->prev = n; list->head = n; } static inline void exec_list_push_tail(struct exec_list *list, struct exec_node *n) { n->next = (struct exec_node *) &list->tail; n->prev = list->tail_pred; n->prev->next = n; list->tail_pred = n; } static inline void exec_list_push_degenerate_list_at_head(struct exec_list *list, struct exec_node *n) { assert(n->prev->next == n); n->prev->next = list->head; list->head->prev = n->prev; n->prev = (struct exec_node *) &list->head; list->head = n; } static inline struct exec_node * exec_list_pop_head(struct exec_list *list) { struct exec_node *const n = exec_list_get_head(list); if (n != NULL) exec_node_remove(n); return n; } static inline void exec_list_move_nodes_to(struct exec_list *list, struct exec_list *target) { if (exec_list_is_empty(list)) { exec_list_make_empty(target); } else { target->head = list->head; target->tail = NULL; target->tail_pred = list->tail_pred; target->head->prev = (struct exec_node *) &target->head; target->tail_pred->next = (struct exec_node *) &target->tail; exec_list_make_empty(list); } } static inline void exec_list_append(struct exec_list *list, struct exec_list *source) { if (exec_list_is_empty(source)) return; /* Link the first node of the source with the last node of the target list. */ list->tail_pred->next = source->head; source->head->prev = list->tail_pred; /* Make the tail of the source list be the tail of the target list. */ list->tail_pred = source->tail_pred; list->tail_pred->next = (struct exec_node *) &list->tail; /* Make the source list empty for good measure. */ exec_list_make_empty(source); } static inline void exec_list_prepend(struct exec_list *list, struct exec_list *source) { exec_list_append(source, list); exec_list_move_nodes_to(source, list); } static inline void exec_node_insert_list_before(struct exec_node *n, struct exec_list *before) { if (exec_list_is_empty(before)) return; before->tail_pred->next = n; before->head->prev = n->prev; n->prev->next = before->head; n->prev = before->tail_pred; exec_list_make_empty(before); } static inline void exec_list_validate(const struct exec_list *list) { const struct exec_node *node; assert(list->head->prev == (const struct exec_node *) &list->head); assert(list->tail == NULL); assert(list->tail_pred->next == (const struct exec_node *) &list->tail); /* We could try to use one of the interators below for this but they all * either require C++ or assume the exec_node is embedded in a structure * which is not the case for this function. */ for (node = list->head; node->next != NULL; node = node->next) { assert(node->next->prev == node); assert(node->prev->next == node); } } #ifdef __cplusplus inline void exec_list::make_empty() { exec_list_make_empty(this); } inline bool exec_list::is_empty() const { return exec_list_is_empty(this); } inline const exec_node *exec_list::get_head() const { return exec_list_get_head_const(this); } inline exec_node *exec_list::get_head() { return exec_list_get_head(this); } inline const exec_node *exec_list::get_tail() const { return exec_list_get_tail_const(this); } inline exec_node *exec_list::get_tail() { return exec_list_get_tail(this); } inline unsigned exec_list::length() const { return exec_list_length(this); } inline void exec_list::push_head(exec_node *n) { exec_list_push_head(this, n); } inline void exec_list::push_tail(exec_node *n) { exec_list_push_tail(this, n); } inline void exec_list::push_degenerate_list_at_head(exec_node *n) { exec_list_push_degenerate_list_at_head(this, n); } inline exec_node *exec_list::pop_head() { return exec_list_pop_head(this); } inline void exec_list::move_nodes_to(exec_list *target) { exec_list_move_nodes_to(this, target); } inline void exec_list::append_list(exec_list *source) { exec_list_append(this, source); } inline void exec_list::prepend_list(exec_list *source) { exec_list_prepend(this, source); } inline void exec_node::insert_before(exec_list *before) { exec_node_insert_list_before(this, before); } #endif #define foreach_in_list(__type, __inst, __list) \ for (__type *(__inst) = (__type *)(__list)->head; \ !(__inst)->is_tail_sentinel(); \ (__inst) = (__type *)(__inst)->next) #define foreach_in_list_reverse(__type, __inst, __list) \ for (__type *(__inst) = (__type *)(__list)->tail_pred; \ !(__inst)->is_head_sentinel(); \ (__inst) = (__type *)(__inst)->prev) /** * This version is safe even if the current node is removed. */ #define foreach_in_list_safe(__type, __node, __list) \ for (__type *__node = (__type *)(__list)->head, \ *__next = (__type *)__node->next; \ __next != NULL; \ __node = __next, __next = (__type *)__next->next) #define foreach_in_list_reverse_safe(__type, __node, __list) \ for (__type *__node = (__type *)(__list)->tail_pred, \ *__prev = (__type *)__node->prev; \ __prev != NULL; \ __node = __prev, __prev = (__type *)__prev->prev) #define foreach_in_list_use_after(__type, __inst, __list) \ __type *(__inst); \ for ((__inst) = (__type *)(__list)->head; \ !(__inst)->is_tail_sentinel(); \ (__inst) = (__type *)(__inst)->next) /** * Iterate through two lists at once. Stops at the end of the shorter list. * * This is safe against either current node being removed or replaced. */ #define foreach_two_lists(__node1, __list1, __node2, __list2) \ for (struct exec_node * __node1 = (__list1)->head, \ * __node2 = (__list2)->head, \ * __next1 = __node1->next, \ * __next2 = __node2->next \ ; __next1 != NULL && __next2 != NULL \ ; __node1 = __next1, \ __node2 = __next2, \ __next1 = __next1->next, \ __next2 = __next2->next) #define foreach_list_typed(__type, __node, __field, __list) \ for (__type * __node = \ exec_node_data(__type, (__list)->head, __field); \ (__node)->__field.next != NULL; \ (__node) = exec_node_data(__type, (__node)->__field.next, __field)) #define foreach_list_typed_reverse(__type, __node, __field, __list) \ for (__type * __node = \ exec_node_data(__type, (__list)->tail_pred, __field); \ (__node)->__field.prev != NULL; \ (__node) = exec_node_data(__type, (__node)->__field.prev, __field)) #define foreach_list_typed_safe(__type, __node, __field, __list) \ for (__type * __node = \ exec_node_data(__type, (__list)->head, __field), \ * __next = \ exec_node_data(__type, (__node)->__field.next, __field); \ __next != NULL; \ __node = __next, __next = \ exec_node_data(__type, (__next)->__field.next, __field)) #define foreach_list_typed_safe_reverse(__type, __node, __field, __list) \ for (__type * __node = \ exec_node_data(__type, (__list)->tail_pred, __field), \ * __prev = \ exec_node_data(__type, (__node)->__field.prev, __field); \ __prev != NULL; \ __node = __prev, __prev = \ exec_node_data(__type, (__prev)->__field.prev, __field)) #endif /* LIST_CONTAINER_H */