182 lines
2.5 KiB
C
182 lines
2.5 KiB
C
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/* Author : Stephen Smalley, <sds@epoch.ncsc.mil> */
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/* FLASK */
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/*
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* Implementation of the double-ended queue type.
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*/
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#include <stdlib.h>
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#include "queue.h"
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queue_t queue_create(void)
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{
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queue_t q;
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q = (queue_t) malloc(sizeof(struct queue_info));
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if (q == NULL)
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return NULL;
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q->head = q->tail = NULL;
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return q;
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}
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int queue_insert(queue_t q, queue_element_t e)
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{
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queue_node_ptr_t newnode;
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if (!q)
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return -1;
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newnode = (queue_node_ptr_t) malloc(sizeof(struct queue_node));
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if (newnode == NULL)
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return -1;
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newnode->element = e;
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newnode->next = NULL;
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if (q->head == NULL) {
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q->head = q->tail = newnode;
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} else {
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q->tail->next = newnode;
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q->tail = newnode;
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}
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return 0;
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}
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int queue_push(queue_t q, queue_element_t e)
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{
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queue_node_ptr_t newnode;
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if (!q)
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return -1;
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newnode = (queue_node_ptr_t) malloc(sizeof(struct queue_node));
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if (newnode == NULL)
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return -1;
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newnode->element = e;
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newnode->next = NULL;
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if (q->head == NULL) {
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q->head = q->tail = newnode;
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} else {
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newnode->next = q->head;
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q->head = newnode;
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}
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return 0;
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}
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queue_element_t queue_remove(queue_t q)
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{
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queue_node_ptr_t node;
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queue_element_t e;
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if (!q)
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return NULL;
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if (q->head == NULL)
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return NULL;
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node = q->head;
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q->head = q->head->next;
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if (q->head == NULL)
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q->tail = NULL;
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e = node->element;
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free(node);
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return e;
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}
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queue_element_t queue_head(queue_t q)
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{
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if (!q)
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return NULL;
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if (q->head == NULL)
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return NULL;
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return q->head->element;
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}
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void queue_destroy(queue_t q)
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{
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queue_node_ptr_t p, temp;
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if (!q)
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return;
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p = q->head;
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while (p != NULL) {
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free(p->element);
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temp = p;
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p = p->next;
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free(temp);
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}
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free(q);
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}
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int queue_map(queue_t q, int (*f) (queue_element_t, void *), void *vp)
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{
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queue_node_ptr_t p;
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int ret;
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if (!q)
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return 0;
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p = q->head;
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while (p != NULL) {
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ret = f(p->element, vp);
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if (ret)
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return ret;
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p = p->next;
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}
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return 0;
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}
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void queue_map_remove_on_error(queue_t q,
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int (*f) (queue_element_t, void *),
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void (*g) (queue_element_t, void *), void *vp)
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{
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queue_node_ptr_t p, last, temp;
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int ret;
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if (!q)
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return;
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last = NULL;
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p = q->head;
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while (p != NULL) {
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ret = f(p->element, vp);
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if (ret) {
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if (last) {
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last->next = p->next;
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if (last->next == NULL)
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q->tail = last;
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} else {
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q->head = p->next;
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if (q->head == NULL)
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q->tail = NULL;
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}
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temp = p;
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p = p->next;
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g(temp->element, vp);
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free(temp);
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} else {
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last = p;
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p = p->next;
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}
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}
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return;
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}
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/* FLASK */
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