/* * 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. * * 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 "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 { return next; } exec_node *get_next() { return next; } const exec_node *get_prev() const { return prev; } exec_node *get_prev() { return prev; } void remove() { next->prev = prev; prev->next = next; next = NULL; prev = NULL; } /** * Link a node with itself * * This creates a sort of degenerate list that is occasionally useful. */ void self_link() { next = this; prev = this; } /** * Insert a node in the list after the current node */ void insert_after(exec_node *after) { after->next = this->next; after->prev = this; this->next->prev = after; this->next = after; } /** * Insert a node in the list before the current node */ void insert_before(exec_node *before) { before->next = this; before->prev = this->prev; this->prev->next = before; this->prev = 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) { replacement->prev = this->prev; replacement->next = this->next; this->prev->next = replacement; this->next->prev = replacement; } /** * Is this the sentinel at the tail of the list? */ bool is_tail_sentinel() const { return this->next == NULL; } /** * Is this the sentinel at the head of the list? */ bool is_head_sentinel() const { return this->prev == NULL; } #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; class iterator { public: void next() { } void *get() { return NULL; } bool has_next() const { return false; } }; class exec_list_iterator : public iterator { public: exec_list_iterator(exec_node *n) : node(n), _next(n->next) { /* empty */ } void next() { node = _next; _next = node->next; } void remove() { node->remove(); } exec_node *get() { return node; } bool has_next() const { return _next != NULL; } private: exec_node *node; exec_node *_next; }; #define foreach_iter(iter_type, iter, container) \ for (iter_type iter = (container) . iterator(); iter.has_next(); iter.next()) #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() { head = (exec_node *) & tail; tail = NULL; tail_pred = (exec_node *) & head; } bool is_empty() const { /* 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 head == (exec_node *) &tail; } const exec_node *get_head() const { return !is_empty() ? head : NULL; } exec_node *get_head() { return !is_empty() ? head : NULL; } const exec_node *get_tail() const { return !is_empty() ? tail_pred : NULL; } exec_node *get_tail() { return !is_empty() ? tail_pred : NULL; } void push_head(exec_node *n) { n->next = head; n->prev = (exec_node *) &head; n->next->prev = n; head = n; } void push_tail(exec_node *n) { n->next = (exec_node *) &tail; n->prev = tail_pred; n->prev->next = n; tail_pred = n; } void push_degenerate_list_at_head(exec_node *n) { assert(n->prev->next == n); n->prev->next = head; head->prev = n->prev; n->prev = (exec_node *) &head; head = 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() { exec_node *const n = this->get_head(); if (n != NULL) n->remove(); return n; } /** * Move all of the nodes from this list to the target list */ void move_nodes_to(exec_list *target) { if (is_empty()) { target->make_empty(); } else { target->head = head; target->tail = NULL; target->tail_pred = tail_pred; target->head->prev = (exec_node *) &target->head; target->tail_pred->next = (exec_node *) &target->tail; make_empty(); } } /** * Append all nodes from the source list to the target list */ void append_list(exec_list *source) { if (source->is_empty()) return; /* Link the first node of the source with the last node of the target list. */ this->tail_pred->next = source->head; source->head->prev = this->tail_pred; /* Make the tail of the source list be the tail of the target list. */ this->tail_pred = source->tail_pred; this->tail_pred->next = (exec_node *) &this->tail; /* Make the source list empty for good measure. */ source->make_empty(); } exec_list_iterator iterator() { return exec_list_iterator(head); } exec_list_iterator iterator() const { return exec_list_iterator((exec_node *) head); } #endif }; #ifdef __cplusplus inline void exec_node::insert_before(exec_list *before) { if (before->is_empty()) return; before->tail_pred->next = this; before->head->prev = this->prev; this->prev->next = before->head; this->prev = before->tail_pred; before->make_empty(); } #endif /** * This version is safe even if the current node is removed. */ #define foreach_list_safe(__node, __list) \ for (exec_node * __node = (__list)->head, * __next = __node->next \ ; __next != NULL \ ; __node = __next, __next = __next->next) #define foreach_list(__node, __list) \ for (exec_node * __node = (__list)->head \ ; (__node)->next != NULL \ ; (__node) = (__node)->next) #define foreach_list_const(__node, __list) \ for (const exec_node * __node = (__list)->head \ ; (__node)->next != NULL \ ; (__node) = (__node)->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_const(__type, __node, __field, __list) \ for (const __type * __node = \ exec_node_data(__type, (__list)->head, __field); \ (__node)->__field.next != NULL; \ (__node) = exec_node_data(__type, (__node)->__field.next, __field)) #endif /* LIST_CONTAINER_H */