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/*
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
*/
#include "RingBuffer.h"
#include <string.h>
RingBuffer::RingBuffer( void )
{
memset( _aucBuffer, 0, SERIAL_BUFFER_SIZE ) ;
clear();
}
void RingBuffer::store_char( uint8_t c )
{
int i = nextIndex(_iHead);
// 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 ( i != _iTail )
{
_aucBuffer[_iHead] = c ;
_iHead = i ;
}
}
void RingBuffer::clear()
{
_iHead = 0;
_iTail = 0;
}
int RingBuffer::read_char()
{
if(_iTail == _iHead)
return -1;
uint8_t value = _aucBuffer[_iTail];
_iTail = nextIndex(_iTail);
return value;
}
int RingBuffer::available()
{
int delta = _iHead - _iTail;
if(delta < 0)
return SERIAL_BUFFER_SIZE + delta;
else
return delta;
}
int RingBuffer::peek()
{
if(_iTail == _iHead)
return -1;
return _aucBuffer[_iTail];
}
int RingBuffer::nextIndex(int index)
{
return (uint32_t)(index + 1) % SERIAL_BUFFER_SIZE;
}
bool RingBuffer::isFull()
{
return (nextIndex(_iHead) == _iTail);
}
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