xref: /openbmc/qemu/audio/rate_template.h (revision 8933882d)
1 /*
2  * QEMU Mixing engine
3  *
4  * Copyright (c) 2004-2005 Vassili Karpov (malc)
5  * Copyright (c) 1998 Fabrice Bellard
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to deal
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 /*
27  * Processed signed long samples from ibuf to obuf.
28  * Return number of samples processed.
29  */
NAME(void * opaque,struct st_sample * ibuf,struct st_sample * obuf,size_t * isamp,size_t * osamp)30 void NAME (void *opaque, struct st_sample *ibuf, struct st_sample *obuf,
31            size_t *isamp, size_t *osamp)
32 {
33     struct rate *rate = opaque;
34     struct st_sample *istart, *iend;
35     struct st_sample *ostart, *oend;
36     struct st_sample ilast, icur, out;
37 #ifdef FLOAT_MIXENG
38     mixeng_real t;
39 #else
40     int64_t t;
41 #endif
42 
43     istart = ibuf;
44     iend = ibuf + *isamp;
45 
46     ostart = obuf;
47     oend = obuf + *osamp;
48 
49     if (rate->opos_inc == (1ULL + UINT_MAX)) {
50         int i, n = *isamp > *osamp ? *osamp : *isamp;
51         for (i = 0; i < n; i++) {
52             OP (obuf[i].l, ibuf[i].l);
53             OP (obuf[i].r, ibuf[i].r);
54         }
55         *isamp = n;
56         *osamp = n;
57         return;
58     }
59 
60     /* without input samples, there's nothing to do */
61     if (ibuf >= iend) {
62         *osamp = 0;
63         return;
64     }
65 
66     ilast = rate->ilast;
67 
68     while (true) {
69 
70         /* read as many input samples so that ipos > opos */
71         while (rate->ipos <= (rate->opos >> 32)) {
72             ilast = *ibuf++;
73             rate->ipos++;
74 
75             /* See if we finished the input buffer yet */
76             if (ibuf >= iend) {
77                 goto the_end;
78             }
79         }
80 
81         /* make sure that the next output sample can be written */
82         if (obuf >= oend) {
83             break;
84         }
85 
86         icur = *ibuf;
87 
88         /* wrap ipos and opos around long before they overflow */
89         if (rate->ipos >= 0x10001) {
90             rate->ipos = 1;
91             rate->opos &= 0xffffffff;
92         }
93 
94         /* interpolate */
95 #ifdef FLOAT_MIXENG
96 #ifdef RECIPROCAL
97         t = (rate->opos & UINT_MAX) * (1.f / UINT_MAX);
98 #else
99         t = (rate->opos & UINT_MAX) / (mixeng_real) UINT_MAX;
100 #endif
101         out.l = (ilast.l * (1.0 - t)) + icur.l * t;
102         out.r = (ilast.r * (1.0 - t)) + icur.r * t;
103 #else
104         t = rate->opos & 0xffffffff;
105         out.l = (ilast.l * ((int64_t) UINT_MAX - t) + icur.l * t) >> 32;
106         out.r = (ilast.r * ((int64_t) UINT_MAX - t) + icur.r * t) >> 32;
107 #endif
108 
109         /* output sample & increment position */
110         OP (obuf->l, out.l);
111         OP (obuf->r, out.r);
112         obuf += 1;
113         rate->opos += rate->opos_inc;
114     }
115 
116 the_end:
117     *isamp = ibuf - istart;
118     *osamp = obuf - ostart;
119     rate->ilast = ilast;
120 }
121 
122 #undef NAME
123 #undef OP
124