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 /* See if we finished the input buffer yet */ 76 if (ibuf >= iend) { 77 goto the_end; 78 } 79 } 80 81 icur = *ibuf; 82 83 /* wrap ipos and opos around long before they overflow */ 84 if (rate->ipos >= 0x10001) { 85 rate->ipos = 1; 86 rate->opos &= 0xffffffff; 87 } 88 89 /* interpolate */ 90 #ifdef FLOAT_MIXENG 91 #ifdef RECIPROCAL 92 t = (rate->opos & UINT_MAX) * (1.f / UINT_MAX); 93 #else 94 t = (rate->opos & UINT_MAX) / (mixeng_real) UINT_MAX; 95 #endif 96 out.l = (ilast.l * (1.0 - t)) + icur.l * t; 97 out.r = (ilast.r * (1.0 - t)) + icur.r * t; 98 #else 99 t = rate->opos & 0xffffffff; 100 out.l = (ilast.l * ((int64_t) UINT_MAX - t) + icur.l * t) >> 32; 101 out.r = (ilast.r * ((int64_t) UINT_MAX - t) + icur.r * t) >> 32; 102 #endif 103 104 /* output sample & increment position */ 105 OP (obuf->l, out.l); 106 OP (obuf->r, out.r); 107 obuf += 1; 108 rate->opos += rate->opos_inc; 109 } 110 111 the_end: 112 *isamp = ibuf - istart; 113 *osamp = obuf - ostart; 114 rate->ilast = ilast; 115 } 116 117 #undef NAME 118 #undef OP 119