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