1 // ----------------------------------------------------------------------------
2 //
3 // Copyright (C) 2013 Fons Adriaensen <fons@linuxaudio.org>
4 //
5 // This program is free software; you can redistribute it and/or modify
6 // it under the terms of the GNU General Public License as published by
7 // the Free Software Foundation; either version 3 of the License, or
8 // (at your option) any later version.
9 //
10 // This program is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 // GNU General Public License for more details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with this program. If not, see <http://www.gnu.org/licenses/>.
17 //
18 // ----------------------------------------------------------------------------
19
20
21 #include <stdlib.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <math.h>
25 #include "cresampler.h"
26
27
CResampler(void)28 CResampler::CResampler (void) :
29 _nchan (0),
30 _buff (0)
31 {
32 reset ();
33 }
34
35
~CResampler(void)36 CResampler::~CResampler (void)
37 {
38 clear ();
39 }
40
41
setup(double ratio,unsigned int nchan)42 int CResampler::setup (double ratio,
43 unsigned int nchan)
44 {
45 if (! nchan) return 1;
46 clear ();
47 _inmax = 50;
48 _buff = new float [nchan * (3 + _inmax)];
49 _nchan = nchan;
50 _pstep = 1 / ratio;
51 return reset ();
52 }
53
54
clear(void)55 void CResampler::clear (void)
56 {
57 delete[] _buff;
58 _buff = 0;
59 _nchan = 0;
60 _inmax = 0;
61 _pstep = 0;
62 reset ();
63 }
64
65
set_phase(double p)66 void CResampler::set_phase (double p)
67 {
68 _phase = p - floor (p);
69 }
70
71
set_ratio(double r)72 void CResampler::set_ratio (double r)
73 {
74 _pstep = 1.0 / r;
75 }
76
77
inpdist(void) const78 double CResampler::inpdist (void) const
79 {
80 return (int)(3 - _nread) - _phase;
81 }
82
83
inpsize(void) const84 int CResampler::inpsize (void) const
85 {
86 return 4;
87 }
88
89
reset(void)90 int CResampler::reset (void)
91 {
92 inp_count = 0;
93 out_count = 0;
94 inp_data = 0;
95 out_data = 0;
96 _index = 0;
97 _phase = 0;
98 _nread = 4;
99 _nzero = 0;
100 return 0;
101 }
102
103
process(void)104 int CResampler::process (void)
105 {
106 unsigned int in, nr, n, c;
107 int nz;
108 double ph;
109 float *pb, a, b, d, m0, m1, m2, m3;
110
111 in = _index;
112 nr = _nread;
113 nz = _nzero;
114 ph = _phase;
115 pb = _buff + in * _nchan;
116
117 while (out_count)
118 {
119 if (nr)
120 {
121 if (inp_count == 0) break;
122 n = (4 - nr) * _nchan;
123 if (inp_data)
124 {
125 for (c = 0; c < _nchan; c++) pb [n + c] = inp_data [c];
126 inp_data += _nchan;
127 nz = 0;
128 }
129 else
130 {
131 for (c = 0; c < _nchan; c++) pb [n + c] = 0;
132 if (nz < 4) nz++;
133 }
134 nr--;
135 inp_count--;
136 }
137 else
138 {
139 n = _nchan;
140 if (out_data)
141 {
142 if (nz < 4)
143 {
144 a = ph;
145 b = 1 - a;
146 d = a * b / 2;
147 m0 = -d * b;
148 m1 = b + (3 * b - 1) * d;
149 m2 = a + (3 * a - 1) * d;
150 m3 = -d * a;
151 for (c = 0; c < n; c++)
152 {
153 *out_data++ = m0 * pb [0]
154 + m1 * pb [n]
155 + m2 * pb [2 * n]
156 + m3 * pb [3 * n];
157 pb++;
158 }
159 pb -= n;
160 }
161 else
162 {
163 for (c = 0; c < n; c++) *out_data++ = 0;
164 }
165 }
166 out_count--;
167
168 ph += _pstep;
169 if (ph >= 1.0)
170 {
171 nr = (unsigned int) floor (ph);
172 ph -= nr;
173 in += nr;
174 pb += nr * _nchan;
175 if (in >= _inmax)
176 {
177 memcpy (_buff, pb, (4 - nr) * _nchan * sizeof (float));
178 in = 0;
179 pb = _buff;
180 }
181 }
182 }
183 }
184
185 _index = in;
186 _nread = nr;
187 _nzero = nz;
188 _phase = ph;
189
190 return 0;
191 }
192
193