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, st_sample_t *ibuf, st_sample_t *obuf,
   31:            int *isamp, int *osamp)
   32: {
   33:     struct rate *rate = opaque;
   34:     st_sample_t *istart, *iend;
   35:     st_sample_t *ostart, *oend;
   36:     st_sample_t ilast, icur, out;
   37: #ifdef FLOAT_MIXENG
   38:     real_t 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:             /* See if we finished the input buffer yet */
   75:             if (ibuf >= iend) {
   76:                 goto the_end;
   77:             }
   78:         }
   79: 
   80:         icur = *ibuf;
   81: 
   82:         /* interpolate */
   83: #ifdef FLOAT_MIXENG
   84: #ifdef RECIPROCAL
   85:         t = (rate->opos & UINT_MAX) * (1.f / UINT_MAX);
   86: #else
   87:         t = (rate->opos & UINT_MAX) / (real_t) UINT_MAX;
   88: #endif
   89:         out.l = (ilast.l * (1.0 - t)) + icur.l * t;
   90:         out.r = (ilast.r * (1.0 - t)) + icur.r * t;
   91: #else
   92:         t = rate->opos & 0xffffffff;
   93:         out.l = (ilast.l * ((int64_t) UINT_MAX - t) + icur.l * t) >> 32;
   94:         out.r = (ilast.r * ((int64_t) UINT_MAX - t) + icur.r * t) >> 32;
   95: #endif
   96: 
   97:         /* output sample & increment position */
   98:         OP (obuf->l, out.l);
   99:         OP (obuf->r, out.r);
  100:         obuf += 1;
  101:         rate->opos += rate->opos_inc;
  102:     }
  103: 
  104: the_end:
  105:     *isamp = ibuf - istart;
  106:     *osamp = obuf - ostart;
  107:     rate->ilast = ilast;
  108: }
  109: 
  110: #undef NAME
  111: #undef OP