86 lines
1.9 KiB
C++
86 lines
1.9 KiB
C++
/*
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Copyright (c) 2014 Arduino. All right reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "RingBuffer.h"
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#include <string.h>
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RingBuffer::RingBuffer( void )
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{
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memset( _aucBuffer, 0, SERIAL_BUFFER_SIZE ) ;
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clear();
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}
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void RingBuffer::store_char( uint8_t c )
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{
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int i = nextIndex(_iHead);
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// if we should be storing the received character into the location
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// just before the tail (meaning that the head would advance to the
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// current location of the tail), we're about to overflow the buffer
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// and so we don't write the character or advance the head.
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if ( i != _iTail )
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{
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_aucBuffer[_iHead] = c ;
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_iHead = i ;
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}
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}
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void RingBuffer::clear()
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{
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_iHead = 0;
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_iTail = 0;
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}
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int RingBuffer::read_char()
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{
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if(_iTail == _iHead)
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return -1;
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uint8_t value = _aucBuffer[_iTail];
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_iTail = nextIndex(_iTail);
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return value;
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}
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int RingBuffer::available()
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{
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int delta = _iHead - _iTail;
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if(delta < 0)
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return SERIAL_BUFFER_SIZE + delta;
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else
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return delta;
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}
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int RingBuffer::peek()
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{
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if(_iTail == _iHead)
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return -1;
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return _aucBuffer[_iTail];
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}
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int RingBuffer::nextIndex(int index)
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{
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return (uint32_t)(index + 1) % SERIAL_BUFFER_SIZE;
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}
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bool RingBuffer::isFull()
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{
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return (nextIndex(_iHead) == _iTail);
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}
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