mirror of https://github.com/ArduPilot/ardupilot
146 lines
3.4 KiB
C++
146 lines
3.4 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
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/// @file AP_Buffer.h
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/// @brief fifo buffer template class
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#ifndef __AP_BUFFER_H__
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#define __AP_BUFFER_H__
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#include <stdint.h>
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/// @class AP_Buffer
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template <class T, uint8_t SIZE>
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class AP_Buffer {
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public:
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// Constructor
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AP_Buffer();
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// clear - removes all points from the curve
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virtual void clear();
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// add - adds an item to the buffer. returns TRUE if successfully added
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virtual bool add( T item );
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// get - returns the next value in the buffer
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virtual T get();
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// peek - check what the next value in the buffer is but don't pull it off
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virtual T peek(uint8_t position = 0);
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// num_values - returns number of values in the buffer
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virtual uint8_t num_items() { return _num_items; }
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// print_buffer - display the contents of the buffer on the serial port
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//virtual void print_buffer();
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protected:
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uint8_t _num_items; // number of items in the buffer
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uint8_t _head; // first item in the buffer (will be returned with the next get call)
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T _buff[SIZE]; // x values of each point on the curve
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};
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// Typedef for convenience
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typedef AP_Buffer<uint8_t,8> AP_BufferUInt8_Size8;
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typedef AP_Buffer<uint8_t,16> AP_BufferUnt8_Size16;
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typedef AP_Buffer<uint8_t,32> AP_BufferUInt8_Size32;
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typedef AP_Buffer<uint8_t,64> AP_BufferUInt8_Size64;
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typedef AP_Buffer<uint8_t,128> AP_BufferUInt8_Size128;
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typedef AP_Buffer<float,5> AP_BufferFloat_Size5;
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typedef AP_Buffer<float,10> AP_BufferFloat_Size10;
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typedef AP_Buffer<float,15> AP_BufferFloat_Size15;
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typedef AP_Buffer<float,20> AP_BufferFloat_Size20;
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// Constructor
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template <class T, uint8_t SIZE>
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AP_Buffer<T,SIZE>::AP_Buffer() :
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_num_items(0)
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{
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// clear the buffer
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clear();
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};
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// clear - removes all points from the curve
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template <class T, uint8_t SIZE>
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void AP_Buffer<T,SIZE>::clear() {
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// clear the curve
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_num_items = 0;
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_head = 0;
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}
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// add - adds an item to the buffer. returns TRUE if successfully added
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template <class T, uint8_t SIZE>
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bool AP_Buffer<T,SIZE>::add( T item )
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{
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// determine position of new item
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uint8_t tail = _head + _num_items;
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if( tail >= SIZE ) {
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tail -= SIZE;
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}
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// add item to buffer
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_buff[tail] = item;
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// increment number of items
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if( _num_items < SIZE ) {
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_num_items++;
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}else{
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// no room for new items so drop oldest item
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_head++;
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if( _head >= SIZE ) {
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_head = 0;
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}
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}
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// indicate success
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return true;
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}
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// get - returns the next value in the buffer
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template <class T, uint8_t SIZE>
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T AP_Buffer<T,SIZE>::get()
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{
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T result;
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// return zero if buffer is empty
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if( _num_items == 0 ) {
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return 0;
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}
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// get next value in buffer
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result = _buff[_head];
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// increment to next point
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_head++;
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if( _head >= SIZE )
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_head = 0;
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// reduce number of items
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_num_items--;
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// return item
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return result;
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}
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// peek - check what the next value in the buffer is but don't pull it off
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template <class T, uint8_t SIZE>
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T AP_Buffer<T,SIZE>::peek(uint8_t position)
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{
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uint8_t j = _head+position;
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// return zero if position is out of range
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if( position >= _num_items ) {
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return 0;
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}
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// wrap around if necessary
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if( j >= SIZE )
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j -= SIZE;
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// return desired value
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return _buff[j];
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}
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#endif // __AP_BUFFER_H__
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