code.delx.au - pulseaudio/blob - src/pulse/volume.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2.1 of the License,
   9   or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #include <pulse/i18n.h>
  30 #include <pulsecore/core-util.h>
  31 #include <pulsecore/macro.h>
  32
  33 #include "volume.h"
  34
  35 int pa_cvolume_equal(const pa_cvolume *a, const pa_cvolume *b) {
  36     int i;
  37     pa_assert(a);
  38     pa_assert(b);
  39
  40     pa_return_val_if_fail(pa_cvolume_valid(a), 0);
  41     pa_return_val_if_fail(pa_cvolume_valid(b), 0);
  42
  43     if (a->channels != b->channels)
  44         return 0;
  45
  46     for (i = 0; i < a->channels; i++)
  47         if (a->values[i] != b->values[i])
  48             return 0;
  49
  50     return 1;
  51 }
  52
  53 pa_cvolume* pa_cvolume_init(pa_cvolume *a) {
  54     unsigned c;
  55
  56     pa_assert(a);
  57
  58     a->channels = 0;
  59
  60     for (c = 0; c < PA_CHANNELS_MAX; c++)
  61         a->values[c] = (pa_volume_t) -1;
  62
  63     return a;
  64 }
  65
  66 pa_cvolume* pa_cvolume_set(pa_cvolume *a, unsigned channels, pa_volume_t v) {
  67     int i;
  68
  69     pa_assert(a);
  70     pa_assert(channels > 0);
  71     pa_assert(channels <= PA_CHANNELS_MAX);
  72
  73     a->channels = (uint8_t) channels;
  74
  75     for (i = 0; i < a->channels; i++)
  76         a->values[i] = v;
  77
  78     return a;
  79 }
  80
  81 pa_volume_t pa_cvolume_avg(const pa_cvolume *a) {
  82     uint64_t sum = 0;
  83     int i;
  84
  85     pa_assert(a);
  86     pa_return_val_if_fail(pa_cvolume_valid(a), PA_VOLUME_MUTED);
  87
  88     for (i = 0; i < a->channels; i++)
  89         sum += a->values[i];
  90
  91     sum /= a->channels;
  92
  93     return (pa_volume_t) sum;
  94 }
  95
  96 pa_volume_t pa_cvolume_max(const pa_cvolume *a) {
  97     pa_volume_t m = 0;
  98     int i;
  99
 100     pa_assert(a);
 101     pa_return_val_if_fail(pa_cvolume_valid(a), PA_VOLUME_MUTED);
 102
 103     for (i = 0; i < a->channels; i++)
 104         if (a->values[i] > m)
 105             m = a->values[i];
 106
 107     return m;
 108 }
 109
 110 pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b) {
 111     return pa_sw_volume_from_linear(pa_sw_volume_to_linear(a) * pa_sw_volume_to_linear(b));
 112 }
 113
 114 pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) {
 115     double v = pa_sw_volume_to_linear(b);
 116
 117     if (v <= 0)
 118         return 0;
 119
 120     return pa_sw_volume_from_linear(pa_sw_volume_to_linear(a) / v);
 121 }
 122
 123 #define USER_DECIBEL_RANGE 60
 124
 125 pa_volume_t pa_sw_volume_from_dB(double dB) {
 126     if (isinf(dB) < 0 || dB <= -USER_DECIBEL_RANGE)
 127         return PA_VOLUME_MUTED;
 128
 129     return (pa_volume_t) lrint((dB/USER_DECIBEL_RANGE+1)*PA_VOLUME_NORM);
 130 }
 131
 132 double pa_sw_volume_to_dB(pa_volume_t v) {
 133     if (v == PA_VOLUME_MUTED)
 134         return PA_DECIBEL_MININFTY;
 135
 136     return ((double) v/PA_VOLUME_NORM-1)*USER_DECIBEL_RANGE;
 137 }
 138
 139 pa_volume_t pa_sw_volume_from_linear(double v) {
 140
 141     if (v <= 0)
 142         return PA_VOLUME_MUTED;
 143
 144     if (v > .999 && v < 1.001)
 145         return PA_VOLUME_NORM;
 146
 147     return pa_sw_volume_from_dB(20*log10(v));
 148 }
 149
 150 double pa_sw_volume_to_linear(pa_volume_t v) {
 151
 152     if (v == PA_VOLUME_MUTED)
 153         return 0;
 154
 155     return pow(10.0, pa_sw_volume_to_dB(v)/20.0);
 156 }
 157
 158 char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c) {
 159     unsigned channel;
 160     pa_bool_t first = TRUE;
 161     char *e;
 162
 163     pa_assert(s);
 164     pa_assert(l > 0);
 165     pa_assert(c);
 166
 167     pa_init_i18n();
 168
 169     if (!pa_cvolume_valid(c)) {
 170         pa_snprintf(s, l, _("(invalid)"));
 171         return s;
 172     }
 173
 174     *(e = s) = 0;
 175
 176     for (channel = 0; channel < c->channels && l > 1; channel++) {
 177         l -= pa_snprintf(e, l, "%s%u: %3u%%",
 178                       first ? "" : " ",
 179                       channel,
 180                       (c->values[channel]*100)/PA_VOLUME_NORM);
 181
 182         e = strchr(e, 0);
 183         first = FALSE;
 184     }
 185
 186     return s;
 187 }
 188
 189 char *pa_volume_snprint(char *s, size_t l, pa_volume_t v) {
 190     pa_assert(s);
 191     pa_assert(l > 0);
 192
 193     pa_init_i18n();
 194
 195     if (v == (pa_volume_t) -1) {
 196         pa_snprintf(s, l, _("(invalid)"));
 197         return s;
 198     }
 199
 200     pa_snprintf(s, l, "%3u%%", (v*100)/PA_VOLUME_NORM);
 201     return s;
 202 }
 203
 204 char *pa_sw_cvolume_snprint_dB(char *s, size_t l, const pa_cvolume *c) {
 205     unsigned channel;
 206     pa_bool_t first = TRUE;
 207     char *e;
 208
 209     pa_assert(s);
 210     pa_assert(l > 0);
 211     pa_assert(c);
 212
 213     pa_init_i18n();
 214
 215     if (!pa_cvolume_valid(c)) {
 216         pa_snprintf(s, l, _("(invalid)"));
 217         return s;
 218     }
 219
 220     *(e = s) = 0;
 221
 222     for (channel = 0; channel < c->channels && l > 1; channel++) {
 223         double f = pa_sw_volume_to_dB(c->values[channel]);
 224
 225         l -= pa_snprintf(e, l, "%s%u: %0.2f dB",
 226                          first ? "" : " ",
 227                          channel,
 228                          isinf(f) < 0 || f <= -USER_DECIBEL_RANGE ? -INFINITY : f);
 229
 230         e = strchr(e, 0);
 231         first = FALSE;
 232     }
 233
 234     return s;
 235 }
 236
 237 char *pa_sw_volume_snprint_dB(char *s, size_t l, pa_volume_t v) {
 238     double f;
 239
 240     pa_assert(s);
 241     pa_assert(l > 0);
 242
 243     pa_init_i18n();
 244
 245     if (v == (pa_volume_t) -1) {
 246         pa_snprintf(s, l, _("(invalid)"));
 247         return s;
 248     }
 249
 250     f = pa_sw_volume_to_dB(v);
 251     pa_snprintf(s, l, "%0.2f dB",
 252                 isinf(f) < 0 || f <= -USER_DECIBEL_RANGE ?  -INFINITY : f);
 253
 254     return s;
 255 }
 256
 257 int pa_cvolume_channels_equal_to(const pa_cvolume *a, pa_volume_t v) {
 258     unsigned c;
 259     pa_assert(a);
 260
 261     pa_return_val_if_fail(pa_cvolume_valid(a), 0);
 262
 263     for (c = 0; c < a->channels; c++)
 264         if (a->values[c] != v)
 265             return 0;
 266
 267     return 1;
 268 }
 269
 270 pa_cvolume *pa_sw_cvolume_multiply(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b) {
 271     unsigned i;
 272
 273     pa_assert(dest);
 274     pa_assert(a);
 275     pa_assert(b);
 276
 277     pa_return_val_if_fail(pa_cvolume_valid(a), NULL);
 278     pa_return_val_if_fail(pa_cvolume_valid(b), NULL);
 279
 280     for (i = 0; i < a->channels && i < b->channels && i < PA_CHANNELS_MAX; i++)
 281         dest->values[i] = pa_sw_volume_multiply(a->values[i], b->values[i]);
 282
 283     dest->channels = (uint8_t) i;
 284
 285     return dest;
 286 }
 287
 288 pa_cvolume *pa_sw_cvolume_divide(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b) {
 289     unsigned i;
 290
 291     pa_assert(dest);
 292     pa_assert(a);
 293     pa_assert(b);
 294
 295     pa_return_val_if_fail(pa_cvolume_valid(a), NULL);
 296     pa_return_val_if_fail(pa_cvolume_valid(b), NULL);
 297
 298     for (i = 0; i < a->channels && i < b->channels && i < PA_CHANNELS_MAX; i++)
 299         dest->values[i] = pa_sw_volume_divide(a->values[i], b->values[i]);
 300
 301     dest->channels = (uint8_t) i;
 302
 303     return dest;
 304 }
 305
 306 int pa_cvolume_valid(const pa_cvolume *v) {
 307     unsigned c;
 308
 309     pa_assert(v);
 310
 311     if (v->channels <= 0 || v->channels > PA_CHANNELS_MAX)
 312         return 0;
 313
 314     for (c = 0; c < v->channels; c++)
 315         if (v->values[c] == (pa_volume_t) -1)
 316             return 0;
 317
 318     return 1;
 319 }
 320
 321 static pa_bool_t on_left(pa_channel_position_t p) {
 322
 323     return
 324         p == PA_CHANNEL_POSITION_FRONT_LEFT ||
 325         p == PA_CHANNEL_POSITION_REAR_LEFT ||
 326         p == PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER ||
 327         p == PA_CHANNEL_POSITION_SIDE_LEFT ||
 328         p == PA_CHANNEL_POSITION_TOP_FRONT_LEFT ||
 329         p == PA_CHANNEL_POSITION_TOP_REAR_LEFT;
 330 }
 331
 332 static pa_bool_t on_right(pa_channel_position_t p) {
 333
 334     return
 335         p == PA_CHANNEL_POSITION_FRONT_RIGHT ||
 336         p == PA_CHANNEL_POSITION_REAR_RIGHT ||
 337         p == PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER ||
 338         p == PA_CHANNEL_POSITION_SIDE_RIGHT ||
 339         p == PA_CHANNEL_POSITION_TOP_FRONT_RIGHT ||
 340         p == PA_CHANNEL_POSITION_TOP_REAR_RIGHT;
 341 }
 342
 343 static pa_bool_t on_center(pa_channel_position_t p) {
 344
 345     return
 346         p == PA_CHANNEL_POSITION_FRONT_CENTER ||
 347         p == PA_CHANNEL_POSITION_REAR_CENTER ||
 348         p == PA_CHANNEL_POSITION_TOP_CENTER ||
 349         p == PA_CHANNEL_POSITION_TOP_FRONT_CENTER ||
 350         p == PA_CHANNEL_POSITION_TOP_REAR_CENTER;
 351 }
 352
 353 static pa_bool_t on_lfe(pa_channel_position_t p) {
 354
 355     return
 356         p == PA_CHANNEL_POSITION_LFE;
 357 }
 358
 359 static pa_bool_t on_front(pa_channel_position_t p) {
 360
 361     return
 362         p == PA_CHANNEL_POSITION_FRONT_LEFT ||
 363         p == PA_CHANNEL_POSITION_FRONT_RIGHT ||
 364         p == PA_CHANNEL_POSITION_FRONT_CENTER ||
 365         p == PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER ||
 366         p == PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER ||
 367         p == PA_CHANNEL_POSITION_TOP_FRONT_LEFT ||
 368         p == PA_CHANNEL_POSITION_TOP_FRONT_RIGHT ||
 369         p == PA_CHANNEL_POSITION_TOP_FRONT_CENTER;
 370 }
 371
 372 static pa_bool_t on_rear(pa_channel_position_t p) {
 373
 374     return
 375         p == PA_CHANNEL_POSITION_REAR_LEFT ||
 376         p == PA_CHANNEL_POSITION_REAR_RIGHT ||
 377         p == PA_CHANNEL_POSITION_REAR_CENTER ||
 378         p == PA_CHANNEL_POSITION_TOP_REAR_LEFT ||
 379         p == PA_CHANNEL_POSITION_TOP_REAR_RIGHT ||
 380         p == PA_CHANNEL_POSITION_TOP_REAR_CENTER;
 381 }
 382
 383 pa_cvolume *pa_cvolume_remap(pa_cvolume *v, const pa_channel_map *from, const pa_channel_map *to) {
 384     int a, b;
 385     pa_cvolume result;
 386
 387     pa_assert(v);
 388     pa_assert(from);
 389     pa_assert(to);
 390
 391     pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
 392     pa_return_val_if_fail(pa_channel_map_valid(from), NULL);
 393     pa_return_val_if_fail(pa_channel_map_valid(to), NULL);
 394     pa_return_val_if_fail(pa_cvolume_compatible_with_channel_map(v, from), NULL);
 395
 396     if (pa_channel_map_equal(from, to))
 397         return v;
 398
 399     result.channels = to->channels;
 400
 401     for (b = 0; b < to->channels; b++) {
 402         pa_volume_t k = 0;
 403         int n = 0;
 404
 405         for (a = 0; a < from->channels; a++)
 406             if (from->map[a] == to->map[b]) {
 407                 k += v->values[a];
 408                 n ++;
 409             }
 410
 411         if (n <= 0) {
 412             for (a = 0; a < from->channels; a++)
 413                 if ((on_left(from->map[a]) && on_left(to->map[b])) ||
 414                     (on_right(from->map[a]) && on_right(to->map[b])) ||
 415                     (on_center(from->map[a]) && on_center(to->map[b])) ||
 416                     (on_lfe(from->map[a]) && on_lfe(to->map[b]))) {
 417
 418                     k += v->values[a];
 419                     n ++;
 420                 }
 421         }
 422
 423         if (n <= 0)
 424             k = pa_cvolume_avg(v);
 425         else
 426             k /= n;
 427
 428         result.values[b] = k;
 429     }
 430
 431     *v = result;
 432     return v;
 433 }
 434
 435 int pa_cvolume_compatible(const pa_cvolume *v, const pa_sample_spec *ss) {
 436
 437     pa_assert(v);
 438     pa_assert(ss);
 439
 440     pa_return_val_if_fail(pa_cvolume_valid(v), 0);
 441     pa_return_val_if_fail(pa_sample_spec_valid(ss), 0);
 442
 443     return v->channels == ss->channels;
 444 }
 445
 446 int pa_cvolume_compatible_with_channel_map(const pa_cvolume *v, const pa_channel_map *cm) {
 447     pa_assert(v);
 448     pa_assert(cm);
 449
 450     pa_return_val_if_fail(pa_cvolume_valid(v), 0);
 451     pa_return_val_if_fail(pa_channel_map_valid(cm), 0);
 452
 453     return v->channels == cm->channels;
 454 }
 455
 456 static void get_avg_lr(const pa_channel_map *map, const pa_cvolume *v, pa_volume_t *l, pa_volume_t *r) {
 457     int c;
 458     pa_volume_t left = 0, right = 0;
 459     unsigned n_left = 0, n_right = 0;
 460
 461     pa_assert(v);
 462     pa_assert(map);
 463     pa_assert(map->channels == v->channels);
 464     pa_assert(l);
 465     pa_assert(r);
 466
 467     for (c = 0; c < map->channels; c++) {
 468         if (on_left(map->map[c])) {
 469             left += v->values[c];
 470             n_left++;
 471         } else if (on_right(map->map[c])) {
 472             right += v->values[c];
 473             n_right++;
 474         }
 475     }
 476
 477     if (n_left <= 0)
 478         *l = PA_VOLUME_NORM;
 479     else
 480         *l = left / n_left;
 481
 482     if (n_right <= 0)
 483         *r = PA_VOLUME_NORM;
 484     else
 485         *r = right / n_right;
 486 }
 487
 488 float pa_cvolume_get_balance(const pa_cvolume *v, const pa_channel_map *map) {
 489     pa_volume_t left, right;
 490
 491     pa_assert(v);
 492     pa_assert(map);
 493
 494     pa_return_val_if_fail(pa_cvolume_valid(v), 0.0f);
 495     pa_return_val_if_fail(pa_channel_map_valid(map), 0.0f);
 496     pa_return_val_if_fail(pa_cvolume_compatible_with_channel_map(v, map), 0.0f);
 497
 498     if (!pa_channel_map_can_balance(map))
 499         return 0.0f;
 500
 501     get_avg_lr(map, v, &left, &right);
 502
 503     if (left == right)
 504         return 0.0f;
 505
 506     /*   1.0,  0.0  =>  -1.0
 507          0.0,  1.0  =>   1.0
 508          0.0,  0.0  =>   0.0
 509          0.5,  0.5  =>   0.0
 510          1.0,  0.5  =>  -0.5
 511          1.0,  0.25 => -0.75
 512          0.75, 0.25 => -0.66
 513          0.5,  0.25 => -0.5   */
 514
 515     if (left > right)
 516         return -1.0f + ((float) right / (float) left);
 517     else
 518         return 1.0f - ((float) left / (float) right);
 519 }
 520
 521 pa_cvolume* pa_cvolume_set_balance(pa_cvolume *v, const pa_channel_map *map, float new_balance) {
 522     pa_volume_t left, nleft, right, nright, m;
 523     unsigned c;
 524
 525     pa_assert(map);
 526     pa_assert(v);
 527     pa_assert(new_balance >= -1.0f);
 528     pa_assert(new_balance <= 1.0f);
 529
 530     pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
 531     pa_return_val_if_fail(pa_channel_map_valid(map), NULL);
 532     pa_return_val_if_fail(pa_cvolume_compatible_with_channel_map(v, map), NULL);
 533
 534     if (!pa_channel_map_can_balance(map))
 535         return v;
 536
 537     get_avg_lr(map, v, &left, &right);
 538
 539     m = PA_MAX(left, right);
 540
 541     if (new_balance <= 0) {
 542         nright  = (new_balance + 1.0f) * m;
 543         nleft = m;
 544     } else  {
 545         nleft = (1.0f - new_balance) * m;
 546         nright = m;
 547     }
 548
 549     for (c = 0; c < map->channels; c++) {
 550         if (on_left(map->map[c])) {
 551             if (left == 0)
 552                 v->values[c] = nleft;
 553             else
 554                 v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nleft) / (uint64_t) left);
 555         } else if (on_right(map->map[c])) {
 556             if (right == 0)
 557                 v->values[c] = nright;
 558             else
 559                 v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nright) / (uint64_t) right);
 560         }
 561     }
 562
 563     return v;
 564 }
 565
 566 pa_cvolume* pa_cvolume_scale(pa_cvolume *v, pa_volume_t max) {
 567     unsigned c;
 568     pa_volume_t t = 0;
 569
 570     pa_assert(v);
 571
 572     pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
 573     pa_return_val_if_fail(max != (pa_volume_t) -1, NULL);
 574
 575     for (c = 0; c < v->channels; c++)
 576         if (v->values[c] > t)
 577             t = v->values[c];
 578
 579     if (t <= 0)
 580         return pa_cvolume_set(v, v->channels, max);
 581
 582     for (c = 0; c < v->channels; c++)
 583         v->values[c] = (pa_volume_t) (((uint64_t)  v->values[c] * (uint64_t) max) / (uint64_t) t);
 584
 585     return v;
 586 }
 587
 588 static void get_avg_fr(const pa_channel_map *map, const pa_cvolume *v, pa_volume_t *f, pa_volume_t *r) {
 589     int c;
 590     pa_volume_t front = 0, rear = 0;
 591     unsigned n_front = 0, n_rear = 0;
 592
 593     pa_assert(v);
 594     pa_assert(map);
 595     pa_assert(map->channels == v->channels);
 596     pa_assert(f);
 597     pa_assert(r);
 598
 599     for (c = 0; c < map->channels; c++) {
 600         if (on_front(map->map[c])) {
 601             front += v->values[c];
 602             n_front++;
 603         } else if (on_rear(map->map[c])) {
 604             rear += v->values[c];
 605             n_rear++;
 606         }
 607     }
 608
 609     if (n_front <= 0)
 610         *f = PA_VOLUME_NORM;
 611     else
 612         *f = front / n_front;
 613
 614     if (n_rear <= 0)
 615         *r = PA_VOLUME_NORM;
 616     else
 617         *r = rear / n_rear;
 618 }
 619
 620 float pa_cvolume_get_fade(const pa_cvolume *v, const pa_channel_map *map) {
 621     pa_volume_t front, rear;
 622
 623     pa_assert(v);
 624     pa_assert(map);
 625
 626     pa_return_val_if_fail(pa_cvolume_valid(v), 0.0f);
 627     pa_return_val_if_fail(pa_channel_map_valid(map), 0.0f);
 628     pa_return_val_if_fail(pa_cvolume_compatible_with_channel_map(v, map), 0.0f);
 629
 630     if (!pa_channel_map_can_fade(map))
 631         return 0.0f;
 632
 633     get_avg_fr(map, v, &front, &rear);
 634
 635     if (front == rear)
 636         return 0.0f;
 637
 638     if (rear > front)
 639         return -1.0f + ((float) front / (float) rear);
 640     else
 641         return 1.0f - ((float) rear / (float) front);
 642 }
 643
 644 pa_cvolume* pa_cvolume_set_fade(pa_cvolume *v, const pa_channel_map *map, float new_fade) {
 645     pa_volume_t front, nfront, rear, nrear, m;
 646     unsigned c;
 647
 648     pa_assert(map);
 649     pa_assert(v);
 650     pa_assert(new_fade >= -1.0f);
 651     pa_assert(new_fade <= 1.0f);
 652
 653     pa_return_val_if_fail(pa_cvolume_valid(v), NULL);
 654     pa_return_val_if_fail(pa_channel_map_valid(map), NULL);
 655     pa_return_val_if_fail(pa_cvolume_compatible_with_channel_map(v, map), NULL);
 656
 657     if (!pa_channel_map_can_fade(map))
 658         return v;
 659
 660     get_avg_fr(map, v, &front, &rear);
 661
 662     m = PA_MAX(front, rear);
 663
 664     if (new_fade <= 0) {
 665         nfront  = (new_fade + 1.0f) * m;
 666         nrear = m;
 667     } else  {
 668         nrear = (1.0f - new_fade) * m;
 669         nfront = m;
 670     }
 671
 672     for (c = 0; c < map->channels; c++) {
 673         if (on_front(map->map[c])) {
 674             if (front == 0)
 675                 v->values[c] = nfront;
 676             else
 677                 v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nfront) / (uint64_t) front);
 678         } else if (on_rear(map->map[c])) {
 679             if (rear == 0)
 680                 v->values[c] = nrear;
 681             else
 682                 v->values[c] = (pa_volume_t) (((uint64_t) v->values[c] * (uint64_t) nrear) / (uint64_t) rear);
 683         }
 684     }
 685
 686     return v;
 687 }