Added queues.h

* source/server/queues.h (QUEUES_H): Defined the interface and structures for universal queues.

source/server/queues.h

@@ -0,0 +1,54 @@
+// =========================================
+// | SilverMUD Server - queues.h           |
+// | Copyright (C) 2023, Barra Ó Catháin   |
+// | See end of file for copyright notice. |
+// =========================================
+#ifndef QUEUES_H
+#define QUEUES_H
+#include "data-type.h"
+#include <stdbool.h>
+
+struct Queue
+{
+	size_t itemCount;
+	enum DataType type;
+	struct QueueNode * front;
+	struct QueueNode * back;
+};
+
+struct QueueNode
+{
+	struct QueueNode * next;
+	void * data;
+};
+
+
+// Functions:
+// ==========
+
+struct Queue * createQueue(enum DataType type);
+int destroyQueue(struct Queue * queue);
+int destroyQueueAndContents(void (*deallocationFunction)(void *), struct Queue * queue);
+
+void * peekFromQueue(struct Queue * queue);
+size_t popFromQueue(struct Queue * queue);
+size_t pushToQueue(enum DataType type, void * data, struct Queue * queue);
+size_t popFromQueueAndDestroy(void (*deallocationFunction)(void *), struct Queue * queue);
+
+#endif
+// ==============================================
+// | End of queues.h, copyright notice follows. |
+// ==============================================
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.