src/queue.c

   1 #include <stdlib.h>
   2 #include "queue.h"
   3
   4 typedef struct _Queue {
   5         void** elems;
   6         int size;
   7         QueueFreeFunc free;
   8 } Queue;
   9
  10 static void free_elem(Queue* queue) {
  11         if (queue->free) {
  12                 for (int i = 0; i < queue->size; i++)
  13                         queue->free(queue->elems[i]);
  14         }
  15         free(queue->elems);
  16 }
  17
  18 Queue* queue_new() {
  19         Queue* q = malloc(sizeof(Queue));
  20         q->size = 0;
  21         q->elems = NULL;
  22         q->free = NULL;
  23         return q;
  24 }
  25
  26 Queue* queue_new_full(QueueFreeFunc free){
  27         Queue* q = malloc(sizeof(Queue));
  28         q->size = 0;
  29         q->elems = NULL;
  30         q->free = free;
  31         return q;
  32 }
  33
  34 void queue_destroy(Queue* queue) {
  35         free_elem(queue);
  36         free(queue);
  37 }
  38
  39 /*
  40 static void extend(Queue* queue, void* elem) {
  41         while (int i = queue->size - 1; i > 0; i--) {
  42                 queue->elems[i] = queue->elems[i - 1]
  43         }
  44         queue->elems[0] elem;
  45 }
  46 */
  47 void* queue_dequeue(Queue* queue) {
  48         if (queue_empty(queue))
  49                 return NULL;
  50         queue->size -= 1;
  51         void* elem = queue->elems[queue->size];
  52         queue->elems[queue->size] = NULL;
  53         queue->elems = realloc(queue->elems, queue->size * sizeof(void*));
  54
  55         return elem;
  56 }
  57
  58 void queue_enqueue(Queue* queue, void* elem) {
  59         if (queue == NULL)
  60                 return;
  61
  62         queue->size += 1;
  63         queue->elems = realloc(queue->elems, queue->size * sizeof(void*));
  64         for (int i = queue->size - 1; i > 0; i--) {
  65                 queue->elems[i] = queue->elems[i - 1];
  66         }
  67         queue->elems[0] = elem;
  68 }
  69
  70 void* queue_front(Queue* queue) {
  71         if (queue_empty(queue))
  72                 return NULL;
  73         return queue->elems[0];
  74 }
  75
  76 void* queue_back(Queue* queue) {
  77         if (queue_empty(queue))
  78                 return NULL;
  79         return queue->elems[queue->size - 1];
  80 }
  81
  82 bool queue_empty(Queue* queue) {
  83         return (queue == NULL || queue->size == 0);
  84 }
  85
  86 void queue_clear(Queue* queue) {
  87         if (queue == NULL)
  88                 return;
  89
  90         free_elem(queue);
  91         queue->size = 0;
  92         queue->elems = NULL;
  93 }
  94
  95 int queue_size(Queue* queue) {
  96         if (queue_empty(queue))
  97                 return 0;
  98         return queue->size;
  99 }