/*
 * BRLTTY - A background process providing access to the console screen (when in
 *          text mode) for a blind person using a refreshable braille display.
 *
 * Copyright (C) 1995-2026 by The BRLTTY Developers.
 *
 * BRLTTY comes with ABSOLUTELY NO WARRANTY.
 *
 * This is free software, placed under the terms of the
 * GNU Lesser General Public License, as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at your option) any
 * later version. Please see the file LICENSE-LGPL for details.
 *
 * Web Page: http://brltty.app/
 *
 * This software is maintained by Dave Mielke <dave@mielke.cc>.
 */

#ifndef BRLTTY_INCLUDED_QUEUE
#define BRLTTY_INCLUDED_QUEUE

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

typedef struct QueueStruct Queue;
typedef struct ElementStruct Element;
typedef void ItemDeallocator (void *item, void *data);
typedef int ItemComparator (const void *newItem, const void *existingItem, void *queueData);

extern Queue *newQueue (ItemDeallocator *deallocateItem, ItemComparator *compareItems);
extern void destroyQueue (Queue *queue);

typedef Queue *QueueCreator (void *data);
extern Queue *getProgramQueue (
  Queue **queue, const char *name, int create,
  QueueCreator *createQueue, void *data
);

extern int getQueueSize (const Queue *queue);
extern int isEmptyQueue (const Queue *queue);

extern void *getQueueData (const Queue *queue);
extern void *setQueueData (Queue *queue, void *data);

extern Element *getQueueHead (const Queue *queue);
extern Element *getQueueElement (const Queue *queue, unsigned int index);

extern Element *getStackHead (const Queue *queue);
extern Element *getStackElement (const Queue *queue, unsigned int index);

extern Element *enqueueItem (Queue *queue, void *item);
extern Element *prequeueItem (Queue *queue, void *item);

extern void *dequeueItem (Queue *queue);
extern int deleteItem (Queue *queue, void *item);

extern Queue *getElementQueue (const Element *element);
extern int getElementIdentifier (const Element *element);
extern void *getElementItem (const Element *element);

extern void deleteElements (Queue *queue);
extern void deleteElement (Element *element);
extern void requeueElement (Element *element);
extern void moveElement (Element *element, Queue *queue);

typedef int ItemTester (const void *item, void *data);
extern Element *findElement (const Queue *queue, ItemTester *testItem, void *data);
extern void *findItem (const Queue *queue, ItemTester *testItem, void *data);
extern Element *findElementWithItem (const Queue *queue, void *item);

typedef int ItemProcessor (void *item, void *data);
extern Element *processQueue (Queue *queue, ItemProcessor *processItem, void *data);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* BRLTTY_INCLUDED_QUEUE */
