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tmk_keyboard/tool/mbed/mbed-sdk/libraries/USBHost/USBHostSerial/MtxCircBuffer.h

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/* mbed USBHost Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MTXCIRCBUFFER_H
#define MTXCIRCBUFFER_H
#include "stdint.h"
#include "rtos.h"
//Mutex protected circular buffer
template<typename T, int size>
class MtxCircBuffer {
public:
MtxCircBuffer() {
write = 0;
read = 0;
}
bool isFull() {
mtx.lock();
bool r = (((write + 1) % size) == read);
mtx.unlock();
return r;
}
bool isEmpty() {
mtx.lock();
bool r = (read == write);
mtx.unlock();
return r;
}
void flush() {
write = 0;
read = 0;
}
void queue(T k) {
mtx.lock();
while (((write + 1) % size) == read) {
mtx.unlock();
Thread::wait(10);
mtx.lock();
}
buf[write++] = k;
write %= size;
mtx.unlock();
}
uint16_t available() {
mtx.lock();
uint16_t a = (write >= read) ? (write - read) : (size - read + write);
mtx.unlock();
return a;
}
bool dequeue(T * c) {
mtx.lock();
bool empty = (read == write);
if (!empty) {
*c = buf[read++];
read %= size;
}
mtx.unlock();
return (!empty);
}
private:
volatile uint16_t write;
volatile uint16_t read;
volatile T buf[size];
Mutex mtx;
};
#endif