/*
 * Copyright (c) 2021-2025, RTduino Development Team
 *
 * SPDX-License-Identifier: LGPL-v2.1
 *
 * https://github.com/RTduino/RTduino
 * https://gitee.com/rtduino/RTduino
 *
 * Change Logs:
 * Date Author Notes
 * 2025年01月05日 Meco Man port to RTduino
 */
/*
 RingBuffer.h - Ring buffer implementation
 Copyright (c) 2014 Arduino. All right reserved.

 This library is free software; you can redistribute it and/or
 modify it 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.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/

#ifdef __cplusplus

#ifndef _RING_BUFFER_
#define _RING_BUFFER_

#include <stdint.h>
#include <string.h>

// Define constants and variables for buffering incoming serial data. We're
// using a ring buffer (I think), in which head is the index of the location
// to which to write the next incoming character and tail is the index of the
// location from which to read.
#define SERIAL_BUFFER_SIZE 64

template <int N>
class RingBufferN
{
 public:
 uint8_t _aucBuffer[N] ;
 volatile int _iHead ;
 volatile int _iTail ;
 volatile int _numElems;

 public:
 RingBufferN( void ) ;
 void store_char( uint8_t c ) ;
 void clear();
 int read_char();
 int available();
 int availableForStore();
 int peek();
 bool isFull();

 private:
 int nextIndex(int index);
 inline bool isEmpty() const { return (_numElems == 0); }
};

typedef RingBufferN<SERIAL_BUFFER_SIZE> RingBuffer;


template <int N>
RingBufferN<N>::RingBufferN( void )
{
 memset( _aucBuffer, 0, N ) ;
 clear();
}

template <int N>
void RingBufferN<N>::store_char( uint8_t c )
{
 // if we should be storing the received character into the location
 // just before the tail (meaning that the head would advance to the
 // current location of the tail), we're about to overflow the buffer
 // and so we don't write the character or advance the head.
 if (!isFull())
 {
 _aucBuffer[_iHead] = c ;
 _iHead = nextIndex(_iHead);
 _numElems = _numElems + 1;
 }
}

template <int N>
void RingBufferN<N>::clear()
{
 _iHead = 0;
 _iTail = 0;
 _numElems = 0;
}

template <int N>
int RingBufferN<N>::read_char()
{
 if (isEmpty())
 return -1;

 uint8_t value = _aucBuffer[_iTail];
 _iTail = nextIndex(_iTail);
 _numElems = _numElems - 1;

 return value;
}

template <int N>
int RingBufferN<N>::available()
{
 return _numElems;
}

template <int N>
int RingBufferN<N>::availableForStore()
{
 return (N - _numElems);
}

template <int N>
int RingBufferN<N>::peek()
{
 if (isEmpty())
 return -1;

 return _aucBuffer[_iTail];
}

template <int N>
int RingBufferN<N>::nextIndex(int index)
{
 return (uint32_t)(index + 1) % N;
}

template <int N>
bool RingBufferN<N>::isFull()
{
 return (_numElems == N);
}

#endif /* _RING_BUFFER_ */
#endif /* __cplusplus */