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tlib/oversampling/HIIR/FPUUpsampler2x.h
2024-05-24 13:28:31 +02:00

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/*
FPUUpsampler2x.h
Copyright (c) 2005 Laurent de Soras
Upsamples by a factor 2 the input signal, using FPU.
Template parameters:
- NC: number of coefficients, > 0
--- Legal stuff ---
This program is free software. It comes without any warranty, to
the extent permitted by applicable law. You can redistribute it
and/or modify it under the terms of the Do What The Fuck You Want
To Public License, Version 2, as published by Sam Hocevar. See
http://sam.zoy.org/wtfpl/COPYING for more details.
*/
#pragma once
#include <array>
#include "FPUStageProc.h"
namespace hiir
{
template <int NC, typename T>
class Upsampler2xFPU
{
public:
enum { NBR_COEFS = NC };
Upsampler2xFPU ();
/*
Name: set_coefs
Description:
Sets filter coefficients. Generate them with the PolyphaseIir2Designer
class.
Call this function before doing any processing.
Input parameters:
- coef_arr: Array of coefficients. There should be as many coefficients as
mentioned in the class template parameter.
*/
void set_coefs (const double coef_arr [NBR_COEFS]);
/*
Name: process_sample
Description:
Upsamples (x2) the input sample, generating two output samples.
Input parameters:
- input: The input sample.
Output parameters:
- out_0: First output sample.
- out_1: Second output sample.
*/
inline void process_sample (T &out_0, T &out_1, T input);
/*
Name: process_block
Description:
Upsamples (x2) the input sample block.
Input and output blocks may overlap, see assert() for details.
Input parameters:
- in_ptr: Input array, containing nbr_spl samples.
- nbr_spl: Number of input samples to process, > 0
Output parameters:
- out_0_ptr: Output sample array, capacity: nbr_spl * 2 samples.
*/
void process_block (T out_ptr [], const T in_ptr [], long nbr_spl);
/*
Name: clear_buffers
Description:
Clears filter memory, as if it processed silence since an infinite amount
of time.
*/
void clear_buffers ();
private:
std::array<T, NBR_COEFS> _coef;
std::array<T, NBR_COEFS> _x;
std::array<T, NBR_COEFS> _y;
private:
bool operator == (const Upsampler2xFPU &other);
bool operator != (const Upsampler2xFPU &other);
}; // class Upsampler2xFPU
template <int NC, typename T>
Upsampler2xFPU <NC, T>::Upsampler2xFPU ()
: _coef ()
, _x ()
, _y ()
{
for (int i = 0; i < NBR_COEFS; ++i)
{
_coef [i] = 0;
}
clear_buffers ();
}
template <int NC, typename T>
void Upsampler2xFPU <NC, T>::set_coefs (const double coef_arr [NBR_COEFS])
{
assert (coef_arr != 0);
for (int i = 0; i < NBR_COEFS; ++i)
{
_coef [i] = static_cast <T> (coef_arr [i]);
}
}
template <int NC, typename T>
void Upsampler2xFPU <NC, T>::process_sample (T &out_0, T &out_1, T input)
{
// assert (&out_0 != 0);
// assert (&out_1 != 0);
T even = input;
T odd = input;
StageProcFPU <NBR_COEFS, T>::process_sample_pos (
NBR_COEFS,
even,
odd,
&_coef [0],
&_x [0],
&_y [0]
);
out_0 = even;
out_1 = odd;
}
template <int NC, typename T>
void Upsampler2xFPU <NC, T>::process_block (T out_ptr [], const T in_ptr [], long nbr_spl)
{
// assert (out_ptr != 0);
// assert (in_ptr != 0);
// assert (out_ptr >= in_ptr + nbr_spl || in_ptr >= out_ptr + nbr_spl);
// assert (nbr_spl > 0);
long pos = 0;
do
{
process_sample (
out_ptr [pos * 2],
out_ptr [pos * 2 + 1],
in_ptr [pos]
);
++ pos;
}
while (pos < nbr_spl);
}
template <int NC, typename T>
void Upsampler2xFPU <NC, T>::clear_buffers ()
{
for (int i = 0; i < NBR_COEFS; ++i)
{
_x [i] = 0;
_y [i] = 0;
}
}
} // namespace hiir