audio/rate_template.h

   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  */
  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     ilast = rate->ilast;
  44
  45     istart = ibuf;
  46     iend = ibuf + *isamp;
  47
  48     ostart = obuf;
  49     oend = obuf + *osamp;
  50
  51     if (rate->opos_inc == (1ULL + UINT_MAX)) {
  52         int i, n = *isamp > *osamp ? *osamp : *isamp;
  53         for (i = 0; i < n; i++) {
  54             OP (obuf[i].l, ibuf[i].l);
  55             OP (obuf[i].r, ibuf[i].r);
  56         }
  57         *isamp = n;
  58         *osamp = n;
  59         return;
  60     }
  61
  62     while (obuf < oend) {
  63
  64         /* Safety catch to make sure we have input samples.  */
  65         if (ibuf >= iend) {
  66             break;
  67         }
  68
  69         /* read as many input samples so that ipos > opos */
  70
  71         while (rate->ipos <= (rate->opos >> 32)) {
  72             ilast = *ibuf++;
  73             rate->ipos++;
  74
  75             /* if ipos overflow, there is  a infinite loop */
  76             if (rate->ipos == 0xffffffff) {
  77                 rate->ipos = 1;
  78                 rate->opos = rate->opos & 0xffffffff;
  79             }
  80             /* See if we finished the input buffer yet */
  81             if (ibuf >= iend) {
  82                 goto the_end;
  83             }
  84         }
  85
  86         icur = *ibuf;
  87
  88         /* interpolate */
  89 #ifdef FLOAT_MIXENG
  90 #ifdef RECIPROCAL
  91         t = (rate->opos & UINT_MAX) * (1.f / UINT_MAX);
  92 #else
  93         t = (rate->opos & UINT_MAX) / (mixeng_real) UINT_MAX;
  94 #endif
  95         out.l = (ilast.l * (1.0 - t)) + icur.l * t;
  96         out.r = (ilast.r * (1.0 - t)) + icur.r * t;
  97 #else
  98         t = rate->opos & 0xffffffff;
  99         out.l = (ilast.l * ((int64_t) UINT_MAX - t) + icur.l * t) >> 32;
 100         out.r = (ilast.r * ((int64_t) UINT_MAX - t) + icur.r * t) >> 32;
 101 #endif
 102
 103         /* output sample & increment position */
 104         OP (obuf->l, out.l);
 105         OP (obuf->r, out.r);
 106         obuf += 1;
 107         rate->opos += rate->opos_inc;
 108     }
 109
 110 the_end:
 111     *isamp = ibuf - istart;
 112     *osamp = obuf - ostart;
 113     rate->ilast = ilast;
 114 }
 115
 116 #undef NAME
 117 #undef OP