https://github.com/smfsw/queue
Queue handling library (designed on Arduino)
https://github.com/smfsw/queue
arduino-library fifo lifo queue
Last synced: 2 months ago
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Queue handling library (designed on Arduino)
- Host: GitHub
- URL: https://github.com/smfsw/queue
- Owner: SMFSW
- License: bsd-3-clause
- Created: 2017-03-22T20:18:15.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2025-04-30T21:19:43.000Z (7 months ago)
- Last Synced: 2025-04-30T22:27:06.169Z (7 months ago)
- Topics: arduino-library, fifo, lifo, queue
- Language: C++
- Homepage:
- Size: 6.63 MB
- Stars: 101
- Watchers: 7
- Forks: 23
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Queue
[](https://github.com/SMFSW)
[](LICENSE)
[](https://www.codefactor.io/repository/github/smfsw/queue)
[](https://smfsw.github.io/Queue)
[](ReleaseNotes.md)
Queue handling library (designed on Arduino)
This library was designed for Arduino, yet may be compiled without change with gcc for other purposes/targets
Queue class has since start been called `Queue`. Unfortunately, on some platforms or when using FreeRTOS, Queue is already declared.
For compatibility purposes, `Queue` class has been renamed to `cppQueue`. Sorry for the inconvenience...
## Usage
- Declare a `cppQueue` instance `(size_t size_rec, uint16_t nb_recs=20, QueueType type=FIFO, bool overwrite=false, void * pQDat=NULL, size_t lenQDat=0)` (called `q` below):
- `size_rec` - size of a record in the queue
- `nb_recs` - number of records in the queue
- `type` - queue implementation type: _FIFO_, _LIFO_
- `overwrite` - overwrite previous records when queue is full if set to _true_
- `pQDat` - pointer to static data queue
- `lenQDat` - length of static data queue (in bytes)
- Push stuff to the queue using `q.push(void * rec)`
- returns `true` if successfully pushed into queue
- returns `false` is queue is full
- Pop stuff from the queue using `q.pop(void * rec)` or `q.pull(void * rec)`
- returns `true` if successfully popped from queue
- returns `false` if queue is empty
- Peek stuff from the queue using `q.peek(void * rec)`
- returns `true` if successfully peeked from queue
- returns `false` if queue is empty
- Drop stuff from the queue using `q.drop(void)`
- returns `true` if successfully dropped from queue
- returns `false` if queue is empty
- Peek stuff at index from the queue using `q.peekIdx(void * rec, uint16_t idx)`
- returns `true` if successfully peeked from queue
- returns `false` if index is out of range
- warning: no associated drop function, not to use with `q.drop`
- Peek latest stored from the queue using `q.peekPrevious(void * rec)`
- returns `true` if successfully peeked from queue
- returns `false` if queue is empty
- warning: no associated drop function, not to use with `q.drop`
- note: only useful with FIFO implementation, use `q.peek` instead with a LIFO
- Other methods:
- `q.isInitialized()`: `true` if initialized properly, `false` otherwise
- `q.isEmpty()`: `true` if empty, `false` otherwise
- `q.isFull()`: `true` if full, `false` otherwise
- `q.sizeOf()`: queue size in bytes (returns 0 in case queue allocation failed)
- `q.getCount()` or `q.nbRecs()`: number of records stored in the queue
- `q.getRemainingCount()`: number of records left in the queue
- `q.clean()` or `q.flush()`: remove all items in the queue
## Notes
- Interrupt safe automation is not implemented in the library. You have to manually disable/enable interrupts where required.
No implementation will be made as it would be an issue when using `peek`/`drop` methods with LIFO implementation:
if an item is put to the queue through interrupt between `peek` and `drop` calls, the `drop` call would drop the wrong (newer) item.
In this particular case, dropping decision must be made before re-enabling interrupts.
## Examples included
- [SimpleQueue.ino](examples/SimpleQueue/SimpleQueue.ino): Simple queue example (both LIFO FIFO implementations can be tested)
- [SimpleQueueStatic.ino](examples/SimpleQueueStatic/SimpleQueueStatic.ino): Simple queue example using static queue data array (both LIFO FIFO implementations can be tested)
- [PointersQueue.ino](examples/PointersQueue/PointersQueue.ino): Queue of string pointers for string processing
- [SerialQueue.ino](examples/SerialQueue/SerialQueue.ino): Print characters received from Serial to Serial after reception of EOT char
- [QueueDuplicates.ino](examples/QueueDuplicates/QueueDuplicates.ino): Simple test to test queue duplicates before pushing to queue
- [QueueIdxPeeking.ino](examples/QueueIdxPeeking/QueueIdxPeeking.ino): Simple test to test queue index picking
- [RolloverTest.ino](examples/RolloverTest/RolloverTest.ino): Simple test to test queue rollover (for lib testing purposes mainly)
- [LibTst.ino](examples/LibTst/LibTst.ino): flexible test (for lib testing purposes mainly)
## See also
[cQueue](https://github.com/SMFSW/cQueue) - C implementation of this library