From 154874afda4a8df885e51c01f7681f04fb0b8e61 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sat, 9 Apr 2022 09:43:53 +0200
Subject: neue Verzeichnisstruktur

---
 src/queue.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 src/queue.c

(limited to 'src/queue.c')

diff --git a/src/queue.c b/src/queue.c
new file mode 100644
index 0000000..6a472ee
--- /dev/null
+++ b/src/queue.c
@@ -0,0 +1,115 @@
+/* Standard C */
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* Project */
+#include "util.h"
+
+/* --8<-- queue_type */
+typedef int T;
+
+struct queue_item {
+	struct queue_item *next;
+	T                  data;
+};
+
+struct queue {
+	struct queue_item *head, *tail;
+};
+/* -->8-- */
+
+/* --8<-- queue_init */
+void
+queue_init(struct queue *queue)
+{
+	queue->head = NULL;
+}
+/* -->8-- */
+
+/* --8<-- queue_put */
+void
+queue_put(struct queue *queue, T data)
+{
+	struct queue_item *new_item;
+
+	if ( (new_item = malloc(sizeof *new_item)) != NULL ) {
+		struct queue_item *tmp = queue->tail;
+		new_item->data         = data;
+		new_item->next         = NULL;
+		queue->tail            = new_item;
+		if ( queue->head == NULL )
+			queue->head = queue->tail;
+		else
+			tmp->next = queue->tail;
+	}
+	else {
+		ERROR("out of memory");
+	}
+}
+/* -->8-- */
+
+/* --8<-- queue_get */
+bool
+queue_get(struct queue *queue, T *data)
+{
+	if ( queue->head ) {
+		struct queue_item *next = queue->head->next;
+
+		if ( data ) {
+			*data = queue->head->data;
+		}
+		free(queue->head);
+		queue->head = next;
+
+		return true;
+	}
+	else
+		return false;
+}
+/* -->8-- */
+
+/* --8<-- queue_empty */
+bool
+queue_empty(struct queue *queue)
+{
+	return queue->head == NULL;
+}
+/* -->8-- */
+
+/* --8<-- queue_free */
+void
+queue_free(struct queue *queue)
+{
+	struct queue_item *item, *next;
+
+	for ( item = queue->head; item; item = next ) {
+		next = item->next;
+		free(item);
+	}
+}
+/* -->8-- */
+
+int
+main()
+{
+	struct queue queue[1];
+
+	queue_init(queue);
+
+	for ( int i = 0; i != 10; ++i ) {
+		queue_put(queue, i);
+	}
+
+	while ( !queue_empty(queue) ) {
+		int i;
+		if ( queue_get(queue, &i) )
+			printf("%d\n", i);
+		else
+			ERROR("this shouldn't happen!");
+	}
+
+	queue_free(queue);
+
+	return EXIT_SUCCESS;
+}
-- 
cgit v1.3