Data structure/circular queue

data_structures/C/CircularQueue.c

@@ -0,0 +1,114 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+/**
+ * Circular Queue implementation
+ */
+
+struct CircularQueue
+{
+  long *_queue;
+  size_t _length;
+  size_t _MAX_LENGTH;
+  size_t _front_idx;
+  size_t _back_idx;
+} typedef CircularQueue;
+
+void circ_queue_build(CircularQueue *);
+int __empty_queue_error(void);
+long circ_queue_front(CircularQueue *);
+long circ_queue_back(CircularQueue *);
+void circ_queue_push(CircularQueue *, long);
+long circ_queue_pop(CircularQueue *);
+int circ_queue_length(CircularQueue *);
+void ___set_circ_queue_MAX_SIZE(CircularQueue *);
+void circ_queue_build(CircularQueue *queue)
+{
+  queue->_MAX_LENGTH = SIZE_MAX;
+  (*queue->_queue) = (long *)calloc(queue->_MAX_LENGTH, sizeof(long));
+  queue->_front_idx = queue->_back_idx = 0;
+  queue->_length = 0;
+}
+
+void ___set_circ_queue_MAX_SIZE(CircularQueue *queue, long long int MAX_SIZE)
+{
+  queue->_MAX_LENGTH = MAX_SIZE;
+}
+
+int __empty_queue_error()
+{
+  printf("Error the queue is empty: -1");
+  return -1;
+}
+
+long circ_queue_front(CircularQueue *queue)
+{
+  if (circ_queue_length(queue) == 0)
+    __empty_queue_error();
+  return queue->_queue[queue->_front_idx];
+}
+
+long circ_queue_back(CircularQueue *queue)
+{
+  if (circ_queue_length(queue) == 0)
+    __empty_queue_error();
+  return queue->_queue[queue->_back_idx - 1];
+}
+
+int circ_queue_length(CircularQueue *queue)
+{
+  return abs(queue->_front_idx - queue->_back_idx);
+}
+
+void circ_queue_push(CircularQueue *queue, long element)
+{
+  queue->_queue[queue->_back_idx] = element;
+  queue->_back_idx++;
+  queue->_back_idx = queue->_back_idx % queue->_MAX_LENGTH;
+}
+
+long circ_queue_pop(CircularQueue *queue)
+{
+  int element = queue->_queue[queue->_front_idx];
+  queue->_front_idx++;
+  queue->_front_idx = queue->_front_idx % queue->_MAX_LENGTH;
+  return element;
+}
+
+void circ_queue_destroy(CircularQueue *queue)
+{
+  free((void *)(&queue->_queue));
+}
+
+void ___test(long expected, long result)
+{
+  assert(expected == result);
+  printf("Expected: %ld ; Result: %ld \n", expected, result);
+}
+
+int main()
+{
+  CircularQueue queue;
+
+  circ_queue_build(&queue);   // queue:
+  circ_queue_push(&queue, 1); // 1
+  circ_queue_push(&queue, 3); // 1 3
+  ___test(1, circ_queue_front(&queue));
+  ___test(3, circ_queue_back(&queue));
+  circ_queue_push(&queue, 4); // 1 3 4
+  ___test(1, circ_queue_front(&queue));
+  ___test(4, circ_queue_back(&queue));
+  circ_queue_pop(&queue); // 3 4
+  ___test(3, circ_queue_front(&queue));
+  ___test(4, circ_queue_back(&queue));
+  circ_queue_pop(&queue); // 4
+  ___test(4, circ_queue_front(&queue));
+  ___test(4, circ_queue_back(&queue));
+  circ_queue_push(&queue, 3);
+
+  ___test(4, circ_queue_front(&queue));
+  ___test(3, circ_queue_back(&queue));
+
+  return 0;
+}