Ardupilot2/libraries/Filter/FilterWithBuffer.h
2012-08-21 19:04:30 -07:00

117 lines
3.9 KiB
C++

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
//
// This 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.
//
/// @file FilterWithBuffer.h
/// @brief A filter with a buffer.
/// This is implemented separately to the base Filter class to get around
/// restrictions caused by the use of templates which makes different sizes essentially
/// completely different classes
#ifndef FilterWithBuffer_h
#define FilterWithBuffer_h
#include <inttypes.h>
#include <AP_Common.h>
#include <Filter.h>
template <class T, uint8_t FILTER_SIZE>
class FilterWithBuffer : public Filter<T>
{
public:
// constructor
FilterWithBuffer();
// apply - Add a new raw value to the filter, retrieve the filtered result
virtual T apply(T sample);
// reset - clear the filter
virtual void reset();
// get filter size
virtual uint8_t get_filter_size() {
return FILTER_SIZE;
};
protected:
T samples[FILTER_SIZE]; // buffer of samples
uint8_t sample_index; // pointer to the next empty slot in the buffer
};
// Typedef for convenience
typedef FilterWithBuffer<int16_t,2> FilterWithBufferInt16_Size2;
typedef FilterWithBuffer<int16_t,3> FilterWithBufferInt16_Size3;
typedef FilterWithBuffer<int16_t,4> FilterWithBufferInt16_Size4;
typedef FilterWithBuffer<int16_t,5> FilterWithBufferInt16_Size5;
typedef FilterWithBuffer<int16_t,6> FilterWithBufferInt16_Size6;
typedef FilterWithBuffer<int16_t,7> FilterWithBufferInt16_Size7;
typedef FilterWithBuffer<uint16_t,2> FilterWithBufferUInt16_Size2;
typedef FilterWithBuffer<uint16_t,3> FilterWithBufferUInt16_Size3;
typedef FilterWithBuffer<uint16_t,4> FilterWithBufferUInt16_Size4;
typedef FilterWithBuffer<uint16_t,5> FilterWithBufferUInt16_Size5;
typedef FilterWithBuffer<uint16_t,6> FilterWithBufferUInt16_Size6;
typedef FilterWithBuffer<uint16_t,7> FilterWithBufferUInt16_Size7;
typedef FilterWithBuffer<int32_t,2> FilterWithBufferInt32_Size2;
typedef FilterWithBuffer<int32_t,3> FilterWithBufferInt32_Size3;
typedef FilterWithBuffer<int32_t,4> FilterWithBufferInt32_Size4;
typedef FilterWithBuffer<int32_t,5> FilterWithBufferInt32_Size5;
typedef FilterWithBuffer<int32_t,6> FilterWithBufferInt32_Size6;
typedef FilterWithBuffer<int32_t,7> FilterWithBufferInt32_Size7;
typedef FilterWithBuffer<uint32_t,2> FilterWithBufferUInt32_Size2;
typedef FilterWithBuffer<uint32_t,3> FilterWithBufferUInt32_Size3;
typedef FilterWithBuffer<uint32_t,4> FilterWithBufferUInt32_Size4;
typedef FilterWithBuffer<uint32_t,5> FilterWithBufferUInt32_Size5;
typedef FilterWithBuffer<uint32_t,6> FilterWithBufferUInt32_Size6;
typedef FilterWithBuffer<uint32_t,7> FilterWithBufferUInt32_Size7;
// Constructor
template <class T, uint8_t FILTER_SIZE>
FilterWithBuffer<T,FILTER_SIZE>::FilterWithBuffer() :
Filter<T>(),
sample_index(0)
{
// clear sample buffer
reset();
}
// reset - clear all samples from the buffer
template <class T, uint8_t FILTER_SIZE>
void FilterWithBuffer<T,FILTER_SIZE>:: reset()
{
// call base class reset
Filter<T>::reset();
// clear samples buffer
for( int8_t i=0; i<FILTER_SIZE; i++ ) {
samples[i] = 0;
}
// reset index back to beginning of the array
sample_index = 0;
}
// apply - take in a new raw sample, and return the filtered results
template <class T, uint8_t FILTER_SIZE>
T FilterWithBuffer<T,FILTER_SIZE>:: apply(T sample)
{
// add sample to array
samples[sample_index++] = sample;
// wrap index if necessary
if( sample_index >= FILTER_SIZE )
sample_index = 0;
// base class doesn't know what filtering to do so we just return the raw sample
return sample;
}
#endif