BlockDelay.hpp

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/**
 * @file blocks.h
 *
 * Controller library code
 */

#pragma once

#include <px4_platform_common/defines.h>
#include <assert.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>
#include <mathlib/math/test/test.hpp>
#include <mathlib/math/filter/LowPassFilter2p.hpp>

#include "block/Block.hpp"
#include "block/BlockParam.hpp"

#include "matrix/math.hpp"

namespace control
{

template<class Type, size_t M, size_t N, size_t LEN>
class __EXPORT BlockDelay: public Block
{
public:
// methods
    BlockDelay(SuperBlock *parent, const char *name) :
        Block(parent, name),
        _h(),
        _index(0),
        _delay(-1)
    {}
    virtual ~BlockDelay() = default;
    matrix::Matrix<Type, M, N> update(const matrix::Matrix<Type, M, N> &u)
    {
        // store current value
        _h[_index] = u;

        // delay starts at zero, then increases to LEN
        _delay += 1;

        if (_delay > (int)(LEN - 1)) {
            _delay = LEN - 1;
        }

        // compute position of delayed value
        int j = _index - _delay;

        if (j < 0) {
            j += LEN;
        }

        // increment storage position
        _index += 1;

        if (_index > (LEN - 1)) {
            _index  = 0;
        }

        // get delayed value
        return _h[j];
    }
    matrix::Matrix<Type, M, N> get(size_t delay)
    {
        int j = _index - delay;

        if (j < 0) { j += LEN; }

        return _h[j];
    }
private:
// attributes
    matrix::Matrix<Type, M, N> _h[LEN];
    size_t _index;
    int _delay;
};

} // namespace control