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queue.c
261 lines (197 loc) · 5.89 KB
/
queue.c
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#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include "queue.h"
#include "slist.h"
Queue *queue_new (void) {
Queue *new_queue = NULL;
new_queue = calloc(1, sizeof(*new_queue));
if (new_queue != NULL) {
new_queue->head = NULL;
new_queue->tail = NULL;
new_queue->length = 0;
}
/* Postcondicion */
assert((int) new_queue->length == slist_length(new_queue->head));
return new_queue;
}
void queue_free (Queue *queue) {
/* Precondition */
assert(queue != NULL);
slist_free(queue->head);
free(queue);
}
bool queue_is_empty (Queue *queue) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return queue->length == 0;
}
unsigned int queue_get_length (Queue *queue) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return queue->length;
}
Queue *queue_copy (Queue *queue) {
Queue *new_queue = NULL;
/* Precondition */
assert(queue != NULL);
new_queue = calloc(1, sizeof(*new_queue));
if (new_queue != NULL) {
new_queue->head = slist_copy(queue->head);
new_queue->tail = slist_last(new_queue->head);
new_queue->length = queue->length;
}
return new_queue;
}
void queue_foreach (Queue *queue, UserFunc(func), void *user_data) {
/* Precondition */
assert(queue != NULL);
slist_foreach(queue->head, func, user_data);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
}
SList *queue_find (Queue *queue, const void *data) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_find(queue->head, data);
}
SList *queue_find_custom (Queue *queue, const void *data, CompareFunc(func)) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_find_custom(queue->head, data, func);
}
void queue_push_head (Queue *queue, void *data) {
/* Precondition */
assert(queue != NULL);
queue->head = slist_prepend (queue->head, data);
if (queue->length == 0) {
queue->tail = queue->head;
}
queue->length++;
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
}
void queue_push_tail (Queue *queue, void *data) {
SList *tmp_tail = NULL;
/* Precondition */
assert(queue != NULL);
tmp_tail = slist_append (queue->tail, data);
if (queue->length == 0) {
queue->head = tmp_tail;
queue->tail = tmp_tail;
}
else {
queue->tail = slist_next(tmp_tail);
}
queue->length++;
/* Postcondicion */
assert(queue->tail != NULL);
assert((int) queue->length == slist_length(queue->head));
}
void queue_push_nth (Queue *queue, void *data, unsigned int n) {
/* Precondition */
assert(queue != NULL);
assert(n <= queue->length);
if (n == 0) {
queue_push_head (queue, data);
}
else if (n == queue->length - 1){
queue_push_tail (queue, data);
}
else {
slist_insert(queue->head, data, n);
queue->length ++;
}
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
}
void *queue_pop_head (Queue *queue) {
void *element_data = NULL;
SList *temp_element = NULL;
/* Precondition */
assert(queue != NULL);
assert(queue->length != 0);
element_data = slist_nth_data(queue->head, 0);
temp_element = slist_next(queue->head);
slist_free_1(queue->head);
queue->head = temp_element;
queue->length--;
if (queue->length == 0) {
queue->tail = NULL;
}
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return element_data;
}
void *queue_pop_tail (Queue *queue) {
void *element_data = NULL;
SList *temp_previous = NULL;
/* Precondition */
assert(queue != NULL);
assert(queue->length != 0);
if (queue->length == 1) {
element_data = slist_nth_data(queue->tail, 0);
slist_free_1(queue->tail);
queue->head = NULL;
queue->tail = NULL;
}
else {
/* Minus 2, because list starts at pos 0 */
temp_previous = slist_nth(queue->head, queue->length - 2);
element_data = slist_nth_data(queue->tail, 0);
slist_free_1(queue->tail);
temp_previous->next = NULL;
queue->tail = temp_previous;
}
queue->length--;
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return element_data;
}
void *queue_peek_head (Queue *queue) {
/* Precondition */
assert(queue != NULL);
assert(queue->length > 0);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_nth_data(queue->head, 0);
}
void *queue_peek_tail (Queue *queue) {
/* Precondition */
assert(queue != NULL);
assert(queue->length > 0);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_nth_data(queue->tail, 0);
}
void *queue_peek_nth (Queue *queue, unsigned int n) {
/* Precondition */
assert(queue != NULL);
assert(queue->length > 0);
assert(n < queue->length);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_nth_data(queue->head, n);
}
int queue_index (Queue *queue, const void *data) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return slist_index(queue->head, data);
}
SList *queue_list (Queue *queue) {
/* Precondition */
assert(queue != NULL);
/* Postcondicion */
assert((int) queue->length == slist_length(queue->head));
return queue->head;
}