ardour/libs/zita-resampler/cresampler.cc

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// ----------------------------------------------------------------------------
//
// Copyright (C) 2013 Fons Adriaensen <fons@linuxaudio.org>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "zita-resampler/cresampler.h"
using namespace ArdourZita;
CResampler::CResampler (void)
: _nchan (0)
, _buff (0)
{
reset ();
}
CResampler::~CResampler (void)
{
clear ();
}
int
CResampler::setup (double ratio,
unsigned int nchan)
{
if (! nchan) return 1;
clear ();
_inmax = 50;
_buff = new float [nchan * (3 + _inmax)];
_nchan = nchan;
_pstep = 1 / ratio;
return reset ();
}
void
CResampler::clear (void)
{
delete[] _buff;
_buff = 0;
_nchan = 0;
_inmax = 0;
_pstep = 0;
reset ();
}
void
CResampler::set_phase (double p)
{
_phase = p - floor (p);
}
void
CResampler::set_ratio (double r)
{
_pstep = 1.0 / r;
}
double
CResampler::inpdist (void) const
{
return (int)(3 - _nread) - _phase;
}
int
CResampler::inpsize (void) const
{
return 4;
}
int
CResampler::reset (void)
{
inp_count = 0;
out_count = 0;
inp_data = 0;
out_data = 0;
_index = 0;
_phase = 0;
_nread = 4;
_nzero = 0;
return 0;
}
int
CResampler::process (void)
{
unsigned int in, nr, n, c;
int nz;
double ph;
float *pb, a, b, d, m0, m1, m2, m3;
in = _index;
nr = _nread;
nz = _nzero;
ph = _phase;
pb = _buff + in * _nchan;
while (out_count) {
if (nr) {
if (inp_count == 0) break;
n = (4 - nr) * _nchan;
if (inp_data) {
for (c = 0; c < _nchan; c++) pb [n + c] = inp_data [c];
inp_data += _nchan;
nz = 0;
} else {
for (c = 0; c < _nchan; c++) pb [n + c] = 0;
if (nz < 4) nz++;
}
nr--;
inp_count--;
} else {
n = _nchan;
if (out_data) {
if (nz < 4) {
a = ph;
b = 1 - a;
d = a * b / 2;
m0 = -d * b;
m1 = b + (3 * b - 1) * d;
m2 = a + (3 * a - 1) * d;
m3 = -d * a;
for (c = 0; c < n; c++) {
*out_data++ = m0 * pb [0]
+ m1 * pb [n]
+ m2 * pb [2 * n]
+ m3 * pb [3 * n];
pb++;
}
pb -= n;
} else {
for (c = 0; c < n; c++) *out_data++ = 0;
}
}
out_count--;
ph += _pstep;
if (ph >= 1.0) {
nr = (unsigned int) floor (ph);
ph -= nr;
in += nr;
pb += nr * _nchan;
if (in >= _inmax) {
memcpy (_buff, pb, (4 - nr) * _nchan * sizeof (float));
in = 0;
pb = _buff;
}
}
}
}
_index = in;
_nread = nr;
_nzero = nz;
_phase = ph;
return 0;
}