mirror of https://github.com/python/cpython
107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
// A doubly-linked list that can be embedded in a struct.
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//
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// Usage:
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// struct llist_node head = LLIST_INIT(head);
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// typedef struct {
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// ...
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// struct llist_node node;
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// ...
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// } MyObj;
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//
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// llist_insert_tail(&head, &obj->node);
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// llist_remove(&obj->node);
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//
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// struct llist_node *node;
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// llist_for_each(node, &head) {
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// MyObj *obj = llist_data(node, MyObj, node);
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// ...
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// }
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//
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#ifndef Py_INTERNAL_LLIST_H
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#define Py_INTERNAL_LLIST_H
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "Py_BUILD_CORE must be defined to include this header"
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#endif
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struct llist_node {
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struct llist_node *next;
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struct llist_node *prev;
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};
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// Get the struct containing a node.
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#define llist_data(node, type, member) (_Py_CONTAINER_OF(node, type, member))
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// Iterate over a list.
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#define llist_for_each(node, head) \
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for (node = (head)->next; node != (head); node = node->next)
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// Iterate over a list, but allow removal of the current node.
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#define llist_for_each_safe(node, head) \
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for (struct llist_node *_next = (node = (head)->next, node->next); \
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node != (head); node = _next, _next = node->next)
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#define LLIST_INIT(head) { &head, &head }
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static inline void
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llist_init(struct llist_node *head)
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{
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head->next = head;
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head->prev = head;
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}
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// Returns 1 if the list is empty, 0 otherwise.
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static inline int
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llist_empty(struct llist_node *head)
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{
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return head->next == head;
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}
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// Appends to the tail of the list.
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static inline void
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llist_insert_tail(struct llist_node *head, struct llist_node *node)
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{
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node->prev = head->prev;
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node->next = head;
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head->prev->next = node;
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head->prev = node;
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}
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// Remove a node from the list.
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static inline void
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llist_remove(struct llist_node *node)
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{
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struct llist_node *prev = node->prev;
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struct llist_node *next = node->next;
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prev->next = next;
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next->prev = prev;
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node->prev = NULL;
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node->next = NULL;
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}
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// Append all nodes from head2 onto head1. head2 is left empty.
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static inline void
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llist_concat(struct llist_node *head1, struct llist_node *head2)
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{
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if (!llist_empty(head2)) {
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head1->prev->next = head2->next;
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head2->next->prev = head1->prev;
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head1->prev = head2->prev;
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head2->prev->next = head1;
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llist_init(head2);
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}
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_LLIST_H */
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