1 files changed, 123 insertions, 0 deletions
diff --git a/libs/zita-resampler/resampler-table.cc b/libs/zita-resampler/resampler-table.cc
new file mode 100644
index 0000000000..ca4cdb69b8
--- /dev/null
+++ b/libs/zita-resampler/resampler-table.cc
@@ -0,0 +1,123 @@
+// ----------------------------------------------------------------------------
+//
+//  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"
+
+using namespace ArdourZita;
+
+Resampler_table  *Resampler_table::_list = 0;
+Resampler_mutex   Resampler_table::_mutex;
+
+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 (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 ();
+}