142 lines
3 KiB
C++
142 lines
3 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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#ifdef __cplusplus
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#ifndef _RING_BUFFER_
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#define _RING_BUFFER_
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#include <stdint.h>
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// Define constants and variables for buffering incoming serial data. We're
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// using a ring buffer (I think), in which head is the index of the location
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// to which to write the next incoming character and tail is the index of the
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// location from which to read.
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#define SERIAL_BUFFER_SIZE 164
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template <int N>
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class RingBufferN
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{
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public:
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uint8_t _aucBuffer[N] ;
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volatile int _iHead ;
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volatile int _iTail ;
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public:
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RingBufferN( void ) ;
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void store_char( uint8_t c ) ;
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void clear();
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int read_char();
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int available();
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int availableForStore();
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int peek();
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bool isFull();
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private:
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int nextIndex(int index);
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};
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typedef RingBufferN<SERIAL_BUFFER_SIZE> RingBuffer;
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template <int N>
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RingBufferN<N>::RingBufferN( void )
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{
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memset( _aucBuffer, 0, N ) ;
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clear();
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}
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template <int N>
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void RingBufferN<N>::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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template <int N>
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void RingBufferN<N>::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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template <int N>
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int RingBufferN<N>::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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template <int N>
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int RingBufferN<N>::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 N + delta;
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else
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return delta;
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}
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template <int N>
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int RingBufferN<N>::availableForStore()
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{
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if (_iHead >= _iTail)
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return N - 1 - _iHead + _iTail;
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else
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return _iTail - _iHead - 1;
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}
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template <int N>
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int RingBufferN<N>::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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template <int N>
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int RingBufferN<N>::nextIndex(int index)
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{
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return (uint32_t)(index + 1) % N;
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}
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template <int N>
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bool RingBufferN<N>::isFull()
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{
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return (nextIndex(_iHead) == _iTail);
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}
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#endif /* _RING_BUFFER_ */
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#endif /* __cplusplus */
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