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/* Copyright (C) 2020-2021 by Jacob Alexander
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// ----- Crates -----
use heapless::spsc::Queue;
use heapless::Vec;
// ----- Enumerations -----
// ----- Structs -----
/// HID-IO byte buffer
/// This buffer is a queue of vecs with static allocation
/// Each vec is fixed sized as HID-IO interface
/// has a fixed transport payload (even if the actual size of the
/// message is less).
/// This buffer has no notion of packet size so it must store the
/// full transport payload.
/// In the minimal scenario a queue size of 1 is used.
///
/// Common HID-IO Vec capacities
/// - 7 bytes (USB 2.0 LS /w HID ID byte)
/// - 8 bytes (USB 2.0 LS)
/// - 63 bytes (USB 2.0 FS /w HID ID byte)
/// - 64 bytes (USB 2.0 FS)
/// - 1023 bytes (USB 2.0 HS /w HID ID byte)
/// - 1024 bytes (USB 2.0 HS)
///
/// The maximum queue size is 255
pub struct Buffer<const Q: usize, const N: usize> {
queue: Queue<Vec<u8, N>, Q>,
}
// ----- Implementations -----
impl<const Q: usize, const N: usize> Default for Buffer<Q, N> {
fn default() -> Self {
Buffer {
queue: Queue::new(),
}
}
}
impl<const Q: usize, const N: usize> Buffer<Q, N> {
/// Constructor for Buffer
///
/// # Remarks
/// Initialize as blank
/// This buffer has a limit of 65535 elements
pub fn new() -> Buffer<Q, N> {
Buffer {
..Default::default()
}
}
/// Checks the first item array
/// Returns None if there are no items in the queue
/// Does not dequeue
pub fn peek(&self) -> Option<&Vec<u8, N>> {
self.queue.peek()
}
/// Dequeues and returns the first item array
/// Returns None if there are no items in the queue
pub fn dequeue(&mut self) -> Option<Vec<u8, N>> {
self.queue.dequeue()
}
/// Enqueues
/// Returns the array if there's not enough space
pub fn enqueue(&mut self, data: Vec<u8, N>) -> Result<(), Vec<u8, N>> {
self.queue.enqueue(data)
}
/// Clears the buffer
/// Needed for some error conditions
pub fn clear(&mut self) {
while !self.queue.is_empty() {
self.dequeue();
}
}
/// Capacity of buffer
pub fn capacity(&self) -> usize {
self.queue.capacity()
}
/// Number of elements stored in the buffer
pub fn len(&self) -> usize {
self.queue.len()
}
/// Buffer empty
pub fn is_empty(&self) -> bool {
self.queue.is_empty()
}
/// Buffer full
pub fn is_full(&self) -> bool {
self.len() == self.capacity()
}
}