-// PingPongOS - PingPong Operating System
-// Prof. Carlos A. Maziero, DINF UFPR
-// Versão 2.0 -- Junho de 2025
-
-// Implementação do TAD fila genérica
-
-/* PEDRO HENRIQUE FRIEDRICH RAMOS : GRR20243133 */
-
-#include "queue.h"
-#include <stdio.h>
-#include <stdlib.h>
-
-/* ------------------------------------------------------------------------- */
-/* Data types ------------------------------------------------------------- */
-
-/* Queue element. */
-struct node_t
-{
- void *item; /* User provided opaque pointer. */
- struct node_t *next; /* Pointer to the next node in the queue. */
-};
-
-/* ------------------------------------------------------------------------- */
-
-/* Queue. */
-struct queue_t
-{
- struct node_t *head; /* Pointer to the first node in the queue. */
- struct node_t *tail; /* Pointer to the last node in the queue. */
- struct node_t *iterator; /* Pointer to the current node. */
- int size; /* Number of nodes in the queue. */
-};
-
-/* ------------------------------------------------------------------------- */
-/* Internal functions ----------------------------------------------------- */
-
-static inline struct node_t *
-node_create (void)
-{
- return calloc (1, sizeof (struct node_t));
-}
-
-/* ------------------------------------------------------------------------- */
-
-static inline void
-node_destroy (struct node_t *node)
-{
- free (node);
-}
-
-/* ------------------------------------------------------------------------- */
-/* Exported functions ----------------------------------------------------- */
-
-struct queue_t *
-queue_create (void)
-{
- return calloc (1, sizeof (struct queue_t));
-}
-
-/* ------------------------------------------------------------------------- */
-
-int
-queue_destroy (struct queue_t *queue)
-{
- struct node_t *n, *next;
-
- if (!queue)
- return ERROR;
-
- n = queue->head;
-
- while (n)
- {
- /* Save the next node pointer before destroying the current node. */
- next = n->next;
- node_destroy (n);
- n = next;
- }
-
- free (queue);
- return NOERROR;
-}
-
-/* ------------------------------------------------------------------------- */
-
-int
-queue_add (struct queue_t *queue, void *item)
-{
- struct node_t *n;
-
- if (!queue || !item)
- return ERROR;
-
- if (!(n = node_create ()))
- return ERROR;
-
- n->item = item;
- ++queue->size;
-
- /* Empty queue, this is the first element. */
- if (!queue->head)
- {
- queue->head = queue->tail = queue->iterator = n;
- return NOERROR;
- }
-
- /* Append to queue. */
- queue->tail = queue->tail->next = n;
- return NOERROR;
-}
-
-/* ------------------------------------------------------------------------- */
-
-int
-queue_del (struct queue_t *queue, void *item)
-{
- struct node_t *n, *prev;
-
- if (!queue || !item)
- return ERROR;
-
- if (!(n = queue->head)) /* Queue is empty. */
- return ERROR;
-
- prev = NULL;
-
- while (n && n->item != item)
- {
- prev = n;
- n = n->next;
- }
-
- if (!n) /* Not found. */
- return ERROR;
-
- if (prev)
- prev->next = n->next;
-
- /* Update boundaries accordingly. */
- if (queue->head == n)
- queue->head = n->next;
-
- if (queue->tail == n)
- queue->tail = prev;
-
- /* Advance the iterator if it points to the removed node. */
- if (queue->iterator == n)
- queue->iterator = n->next;
-
- --queue->size;
- node_destroy (n);
- return NOERROR;
-}
-
-/* ------------------------------------------------------------------------- */
-
-bool
-queue_has (struct queue_t *queue, void *item)
-{
- struct node_t *n;
-
- if (!queue || !item)
- return false;
-
- if (!(n = queue->head))
- return false;
-
- /* Traverse until the item is found or the end is reached. */
- while (n->item != item && (n = n->next))
- ;
-
- return n != NULL;
-}
-
-/* ------------------------------------------------------------------------- */
-
-int
-queue_size (struct queue_t *queue)
-{
- if (!queue)
- return ERROR;
-
- return queue->size;
-}
-
-/* ------------------------------------------------------------------------- */
-
-void *
-queue_head (struct queue_t *queue)
-{
- if (!queue || !queue->head)
- return NULL;
-
- queue->iterator = queue->head;
-
- return queue->head->item;
-}
-
-/* ------------------------------------------------------------------------- */
-
-void *
-queue_next (struct queue_t *queue)
-{
- if (!queue || !queue->iterator)
- return NULL;
-
- queue->iterator = queue->iterator->next;
-
- if (!queue->iterator)
- return NULL;
-
- return queue->iterator->item;
-}
-
-/* ------------------------------------------------------------------------- */
-
-void *
-queue_item (struct queue_t *queue)
-{
- if (!queue || !queue->iterator)
- return NULL;
-
- return queue->iterator->item;
-}
-
-/* ------------------------------------------------------------------------- */
-
-void
-queue_print (char *name, struct queue_t *queue, void (func) (void *))
-{
- struct node_t *n;
-
- if (!name)
- return;
-
- printf ("%s: ", name);
-
- if (!queue)
- {
- puts ("undef");
- return;
- }
-
- fputs ("[ ", stdout);
-
- for (n = queue->head; n; n = n->next)
- {
- if (func)
- func (n->item);
-
- else
- fputs ("undef", stdout);
-
- putchar (' ');
- }
-
- printf ("] (%d items)\n", queue->size);
-}
-
-/* ------------------------------------------------------------------------- */
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