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 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