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Diffstat (limited to 'libs/resampler-table.cc')
| -rw-r--r-- | libs/resampler-table.cc | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/libs/resampler-table.cc b/libs/resampler-table.cc new file mode 100644 index 0000000..daaf9f3 --- /dev/null +++ b/libs/resampler-table.cc @@ -0,0 +1,161 @@ +// ---------------------------------------------------------------------------- +// +// Copyright (C) 2006-2012 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/resampler-table.h> + + +int zita_resampler_major_version (void) +{ + return ZITA_RESAMPLER_MAJOR_VERSION; +} + + +int zita_resampler_minor_version (void) +{ + return ZITA_RESAMPLER_MINOR_VERSION; +} + + +static double sinc (double x) +{ + x = fabs (x); + if (x < 1e-6) return 1.0; + x *= M_PI; + return sin (x) / x; +} + + +static double wind (double x) +{ + x = fabs (x); + if (x >= 1.0) return 0.0f; + x *= M_PI; + return 0.384 + 0.500 * cos (x) + 0.116 * cos (2 * x); +} + + + +Resampler_table *Resampler_table::_list = 0; +Resampler_mutex Resampler_table::_mutex; + + +Resampler_table::Resampler_table (double fr, unsigned int hl, unsigned int np) : + _next (0), + _refc (0), + _fr (fr), + _hl (hl), + _np (np) +{ + unsigned int i, j; + double t; + float *p; + + _ctab = new float [hl * (np + 1)]; + p = _ctab; + for (j = 0; j <= np; j++) + { + t = (double) j / (double) np; + for (i = 0; i < hl; i++) + { + p [hl - i - 1] = (float)(fr * sinc (t * fr) * wind (t / hl)); + t += 1; + } + p += hl; + } +} + + +Resampler_table::~Resampler_table (void) +{ + delete[] _ctab; +} + + +Resampler_table *Resampler_table::create (double fr, unsigned int hl, unsigned int np) +{ + Resampler_table *P; + + _mutex.lock (); + P = _list; + while (P) + { + if ((fr >= P->_fr * 0.999) && (fr <= P->_fr * 1.001) && (hl == P->_hl) && (np == P->_np)) + { + P->_refc++; + _mutex.unlock (); + return P; + } + P = P->_next; + } + P = new Resampler_table (fr, hl, np); + P->_refc = 1; + P->_next = _list; + _list = P; + _mutex.unlock (); + return P; +} + + +void Resampler_table::destroy (Resampler_table *T) +{ + Resampler_table *P, *Q; + + _mutex.lock (); + if (T) + { + T->_refc--; + if (T->_refc == 0) + { + P = _list; + Q = 0; + while (P) + { + if (P == T) + { + if (Q) Q->_next = T->_next; + else _list = T->_next; + break; + } + Q = P; + P = P->_next; + } + delete T; + } + } + _mutex.unlock (); +} + + +void Resampler_table::print_list (void) +{ + Resampler_table *P; + + printf ("Resampler table\n----\n"); + for (P = _list; P; P = P->_next) + { + printf ("refc = %3d fr = %10.6lf hl = %4d np = %4d\n", P->_refc, P->_fr, P->_hl, P->_np); + } + printf ("----\n\n"); +} + |