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Diffstat (limited to 'libs/cresampler.cc')
| -rw-r--r-- | libs/cresampler.cc | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/libs/cresampler.cc b/libs/cresampler.cc new file mode 100644 index 0000000..ca3cabf --- /dev/null +++ b/libs/cresampler.cc @@ -0,0 +1,192 @@ +// ---------------------------------------------------------------------------- +// +// 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> + + +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; +} + |