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circular buffer library for Arduino (C++)
/*
CircularBuffer.h - circular buffer library for Arduino.
Copyright (c) 2009 Hiroki Yagita.
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.
*/
#ifndef CIRCULARBUFFER_h
#define CIRCULARBUFFER_h
#include <inttypes.h>
template <typename T, uint16_t Size>
class CircularBuffer {
public:
enum {
Empty = 0,
Half = Size / 2,
Full = Size,
};
CircularBuffer() :
wp_(buf_), rp_(buf_), tail_(buf_+Size), remain_(0) {}
~CircularBuffer() {}
void push(T value) {
*wp_++ = value;
remain_++;
if (wp_ == tail_) wp_ = buf_;
}
T pop() {
T result = *rp_++;
remain_--;
if (rp_ == tail_) rp_ = buf_;
return result;
}
int remain() const {
return remain_;
}
private:
T buf_[Size];
T *wp_;
T *rp_;
T *tail_;
uint16_t remain_;
};
#endif
@EduardoG26

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EduardoG26 commented Jun 11, 2015

Hi.
Great work.
I think pop should be protected against IRQ for better stability when push is called from inside an irq. (This is a very popular case).

@yagihiro

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yagihiro commented Sep 9, 2016

Hi, EduardoG26

Thanks!
This code is a simple implementation when I develop a small application for Arduino.
If you use it for reentrable case, you should make it easy!

@loco28

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loco28 commented Dec 3, 2017

Hello,
First I;m not a specialist of ARDUINO, just beginner
If I want to stock 2 data (e.g: address and data), may I write: push(address, data)?

@yagihiro

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yagihiro commented Apr 19, 2018

Hi @loco28

For example:

struct Thing {
  int addr;
  void *data;
};

CircularBuffer<Thing, 256> buffer;

buffer.push(Thing{addr1, data1});
// ...

if 0 < buffer.remain() {
  auto data = buffer.pop();
  // ...
}
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