Package list libsdl2-mixer / debian/2.0.4+dfsg1-1 mixer.c
debian/2.0.4+dfsg1-1

Tree @debian/2.0.4+dfsg1-1 (Download .tar.gz)

mixer.c @debian/2.0.4+dfsg1-1raw · history · blame

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
/*
  SDL_mixer:  An audio mixer library based on the SDL library
  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/* $Id$ */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"

#include "SDL_mixer.h"
#include "mixer.h"
#include "music.h"
#include "load_aiff.h"
#include "load_voc.h"

#define __MIX_INTERNAL_EFFECT__
#include "effects_internal.h"

/* Magic numbers for various audio file formats */
#define RIFF        0x46464952      /* "RIFF" */
#define WAVE        0x45564157      /* "WAVE" */
#define FORM        0x4d524f46      /* "FORM" */
#define CREA        0x61657243      /* "Crea" */

static int audio_opened = 0;
static SDL_AudioSpec mixer;
static SDL_AudioDeviceID audio_device;

typedef struct _Mix_effectinfo
{
    Mix_EffectFunc_t callback;
    Mix_EffectDone_t done_callback;
    void *udata;
    struct _Mix_effectinfo *next;
} effect_info;

static struct _Mix_Channel {
    Mix_Chunk *chunk;
    int playing;
    int paused;
    Uint8 *samples;
    int volume;
    int looping;
    int tag;
    Uint32 expire;
    Uint32 start_time;
    Mix_Fading fading;
    int fade_volume;
    int fade_volume_reset;
    Uint32 fade_length;
    Uint32 ticks_fade;
    effect_info *effects;
} *mix_channel = NULL;

static effect_info *posteffects = NULL;

static int num_channels;
static int reserved_channels = 0;


/* Support for hooking into the mixer callback system */
static void (SDLCALL *mix_postmix)(void *udata, Uint8 *stream, int len) = NULL;
static void *mix_postmix_data = NULL;

/* rcg07062001 callback to alert when channels are done playing. */
static void (SDLCALL *channel_done_callback)(int channel) = NULL;

/* Support for user defined music functions */
static void (SDLCALL *mix_music)(void *udata, Uint8 *stream, int len) = music_mixer;
static void *music_data = NULL;

/* rcg06042009 report available decoders at runtime. */
static const char **chunk_decoders = NULL;
static int num_decoders = 0;


int Mix_GetNumChunkDecoders(void)
{
    return(num_decoders);
}

const char *Mix_GetChunkDecoder(int index)
{
    if ((index < 0) || (index >= num_decoders)) {
        return NULL;
    }
    return(chunk_decoders[index]);
}

SDL_bool Mix_HasChunkDecoder(const char *name)
{
    int index;
    for (index = 0; index < num_decoders; ++index) {
        if (SDL_strcasecmp(name, chunk_decoders[index]) == 0) {
            return SDL_TRUE;
        }
    }
    return SDL_FALSE;
}

void add_chunk_decoder(const char *decoder)
{
    int i;
    void *ptr;

    /* Check to see if we already have this decoder */
    for (i = 0; i < num_decoders; ++i) {
        if (SDL_strcmp(chunk_decoders[i], decoder) == 0) {
            return;
        }
    }

    ptr = SDL_realloc((void *)chunk_decoders, (num_decoders + 1) * sizeof (const char *));
    if (ptr == NULL) {
        return;  /* oh well, go on without it. */
    }
    chunk_decoders = (const char **) ptr;
    chunk_decoders[num_decoders++] = decoder;
}

/* rcg06192001 get linked library's version. */
const SDL_version *Mix_Linked_Version(void)
{
    static SDL_version linked_version;
    SDL_MIXER_VERSION(&linked_version);
    return(&linked_version);
}

int Mix_Init(int flags)
{
    int result = 0;

    if (flags & MIX_INIT_FLAC) {
        if (load_music_type(MUS_FLAC)) {
            open_music_type(MUS_FLAC);
            result |= MIX_INIT_FLAC;
        } else {
            Mix_SetError("FLAC support not available");
        }
    }
    if (flags & MIX_INIT_MOD) {
        if (load_music_type(MUS_MOD)) {
            open_music_type(MUS_MOD);
            result |= MIX_INIT_MOD;
        } else {
            Mix_SetError("MOD support not available");
        }
    }
    if (flags & MIX_INIT_MP3) {
        if (load_music_type(MUS_MP3)) {
            open_music_type(MUS_MP3);
            result |= MIX_INIT_MP3;
        } else {
            Mix_SetError("MP3 support not available");
        }
    }
    if (flags & MIX_INIT_OGG) {
        if (load_music_type(MUS_OGG)) {
            open_music_type(MUS_OGG);
            result |= MIX_INIT_OGG;
        } else {
            Mix_SetError("OGG support not available");
        }
    }
    if (flags & MIX_INIT_OPUS) {
        if (load_music_type(MUS_OPUS)) {
            open_music_type(MUS_OPUS);
            result |= MIX_INIT_OPUS;
        } else {
            Mix_SetError("OPUS support not available");
        }
    }
    if (flags & MIX_INIT_MID) {
        if (load_music_type(MUS_MID)) {
            open_music_type(MUS_MID);
            result |= MIX_INIT_MID;
        } else {
            Mix_SetError("MIDI support not available");
        }
    }
    return result;
}

void Mix_Quit()
{
    unload_music();
}

static int _Mix_remove_all_effects(int channel, effect_info **e);

/*
 * rcg06122001 Cleanup effect callbacks.
 *  MAKE SURE Mix_LockAudio() is called before this (or you're in the
 *   audio callback).
 */
static void _Mix_channel_done_playing(int channel)
{
    if (channel_done_callback) {
        channel_done_callback(channel);
    }

    /*
     * Call internal function directly, to avoid locking audio from
     *   inside audio callback.
     */
    _Mix_remove_all_effects(channel, &mix_channel[channel].effects);
}


static void *Mix_DoEffects(int chan, void *snd, int len)
{
    int posteffect = (chan == MIX_CHANNEL_POST);
    effect_info *e = ((posteffect) ? posteffects : mix_channel[chan].effects);
    void *buf = snd;

    if (e != NULL) {    /* are there any registered effects? */
        /* if this is the postmix, we can just overwrite the original. */
        if (!posteffect) {
            buf = SDL_malloc(len);
            if (buf == NULL) {
                return(snd);
            }
            SDL_memcpy(buf, snd, len);
        }

        for (; e != NULL; e = e->next) {
            if (e->callback != NULL) {
                e->callback(chan, buf, len, e->udata);
            }
        }
    }

    /* be sure to SDL_free() the return value if != snd ... */
    return(buf);
}


/* Mixing function */
static void SDLCALL
mix_channels(void *udata, Uint8 *stream, int len)
{
    Uint8 *mix_input;
    int i, mixable, volume = MIX_MAX_VOLUME;
    Uint32 sdl_ticks;

#if SDL_VERSION_ATLEAST(1, 3, 0)
    /* Need to initialize the stream in SDL 1.3+ */
    SDL_memset(stream, mixer.silence, len);
#endif

    /* Mix the music (must be done before the channels are added) */
    mix_music(music_data, stream, len);

    /* Mix any playing channels... */
    sdl_ticks = SDL_GetTicks();
    for (i=0; i<num_channels; ++i) {
        if (!mix_channel[i].paused) {
            if (mix_channel[i].expire > 0 && mix_channel[i].expire < sdl_ticks) {
                /* Expiration delay for that channel is reached */
                mix_channel[i].playing = 0;
                mix_channel[i].looping = 0;
                mix_channel[i].fading = MIX_NO_FADING;
                mix_channel[i].expire = 0;
                _Mix_channel_done_playing(i);
            } else if (mix_channel[i].fading != MIX_NO_FADING) {
                Uint32 ticks = sdl_ticks - mix_channel[i].ticks_fade;
                if (ticks >= mix_channel[i].fade_length) {
                    Mix_Volume(i, mix_channel[i].fade_volume_reset); /* Restore the volume */
                    if(mix_channel[i].fading == MIX_FADING_OUT) {
                        mix_channel[i].playing = 0;
                        mix_channel[i].looping = 0;
                        mix_channel[i].expire = 0;
                        _Mix_channel_done_playing(i);
                    }
                    mix_channel[i].fading = MIX_NO_FADING;
                } else {
                    if (mix_channel[i].fading == MIX_FADING_OUT) {
                        Mix_Volume(i, (mix_channel[i].fade_volume * (mix_channel[i].fade_length-ticks))
                                   / mix_channel[i].fade_length);
                    } else {
                        Mix_Volume(i, (mix_channel[i].fade_volume * ticks) / mix_channel[i].fade_length);
                    }
                }
            }
            if (mix_channel[i].playing > 0) {
                int index = 0;
                int remaining = len;
                while (mix_channel[i].playing > 0 && index < len) {
                    remaining = len - index;
                    volume = (mix_channel[i].volume*mix_channel[i].chunk->volume) / MIX_MAX_VOLUME;
                    mixable = mix_channel[i].playing;
                    if (mixable > remaining) {
                        mixable = remaining;
                    }

                    mix_input = Mix_DoEffects(i, mix_channel[i].samples, mixable);
                    SDL_MixAudioFormat(stream+index,mix_input,mixer.format,mixable,volume);
                    if (mix_input != mix_channel[i].samples)
                        SDL_free(mix_input);

                    mix_channel[i].samples += mixable;
                    mix_channel[i].playing -= mixable;
                    index += mixable;

                    /* rcg06072001 Alert app if channel is done playing. */
                    if (!mix_channel[i].playing && !mix_channel[i].looping) {
                        _Mix_channel_done_playing(i);
                    }
                }

                /* If looping the sample and we are at its end, make sure
                   we will still return a full buffer */
                while (mix_channel[i].looping && index < len) {
                    int alen = mix_channel[i].chunk->alen;
                    remaining = len - index;
                    if (remaining > alen) {
                        remaining = alen;
                    }

                    mix_input = Mix_DoEffects(i, mix_channel[i].chunk->abuf, remaining);
                    SDL_MixAudioFormat(stream+index, mix_input, mixer.format, remaining, volume);
                    if (mix_input != mix_channel[i].chunk->abuf)
                        SDL_free(mix_input);

                    if (mix_channel[i].looping > 0) {
                        --mix_channel[i].looping;
                    }
                    mix_channel[i].samples = mix_channel[i].chunk->abuf + remaining;
                    mix_channel[i].playing = mix_channel[i].chunk->alen - remaining;
                    index += remaining;
                }
                if (! mix_channel[i].playing && mix_channel[i].looping) {
                    if (mix_channel[i].looping > 0) {
                        --mix_channel[i].looping;
                    }
                    mix_channel[i].samples = mix_channel[i].chunk->abuf;
                    mix_channel[i].playing = mix_channel[i].chunk->alen;
                }
            }
        }
    }

    /* rcg06122001 run posteffects... */
    Mix_DoEffects(MIX_CHANNEL_POST, stream, len);

    if (mix_postmix) {
        mix_postmix(mix_postmix_data, stream, len);
    }
}

#if 0
static void PrintFormat(char *title, SDL_AudioSpec *fmt)
{
    printf("%s: %d bit %s audio (%s) at %u Hz\n", title, (fmt->format&0xFF),
            (fmt->format&0x8000) ? "signed" : "unsigned",
            (fmt->channels > 2) ? "surround" :
            (fmt->channels > 1) ? "stereo" : "mono", fmt->freq);
}
#endif

/* Open the mixer with a certain desired audio format */
int Mix_OpenAudioDevice(int frequency, Uint16 format, int nchannels, int chunksize,
                        const char* device, int allowed_changes)
{
    int i;
    SDL_AudioSpec desired;

    /* This used to call SDL_OpenAudio(), which initializes the audio
       subsystem if necessary. Since SDL_OpenAudioDevice() doesn't,
       we have to handle this case here. */
    if (!SDL_WasInit(SDL_INIT_AUDIO)) {
        if (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) {
            return -1;
        }
    }

    /* If the mixer is already opened, increment open count */
    if (audio_opened) {
        if (format == mixer.format && nchannels == mixer.channels) {
            ++audio_opened;
            return(0);
        }
        while (audio_opened) {
            Mix_CloseAudio();
        }
    }

    /* Set the desired format and frequency */
    desired.freq = frequency;
    desired.format = format;
    desired.channels = nchannels;
    desired.samples = chunksize;
    desired.callback = mix_channels;
    desired.userdata = NULL;

    /* Accept nearly any audio format */
    if ((audio_device = SDL_OpenAudioDevice(device, 0, &desired, &mixer, allowed_changes)) == 0) {
        return(-1);
    }
#if 0
    PrintFormat("Audio device", &mixer);
#endif

    num_channels = MIX_CHANNELS;
    mix_channel = (struct _Mix_Channel *) SDL_malloc(num_channels * sizeof(struct _Mix_Channel));

    /* Clear out the audio channels */
    for (i=0; i<num_channels; ++i) {
        mix_channel[i].chunk = NULL;
        mix_channel[i].playing = 0;
        mix_channel[i].looping = 0;
        mix_channel[i].volume = SDL_MIX_MAXVOLUME;
        mix_channel[i].fade_volume = SDL_MIX_MAXVOLUME;
        mix_channel[i].fade_volume_reset = SDL_MIX_MAXVOLUME;
        mix_channel[i].fading = MIX_NO_FADING;
        mix_channel[i].tag = -1;
        mix_channel[i].expire = 0;
        mix_channel[i].effects = NULL;
        mix_channel[i].paused = 0;
    }
    Mix_VolumeMusic(SDL_MIX_MAXVOLUME);

    _Mix_InitEffects();

    add_chunk_decoder("WAVE");
    add_chunk_decoder("AIFF");
    add_chunk_decoder("VOC");

    /* Initialize the music players */
    open_music(&mixer);

    audio_opened = 1;
    SDL_PauseAudioDevice(audio_device, 0);
    return(0);
}

/* Open the mixer with a certain desired audio format */
int Mix_OpenAudio(int frequency, Uint16 format, int nchannels, int chunksize)
{
    return Mix_OpenAudioDevice(frequency, format, nchannels, chunksize, NULL,
                                SDL_AUDIO_ALLOW_FREQUENCY_CHANGE |
                                SDL_AUDIO_ALLOW_CHANNELS_CHANGE);
}

/* Dynamically change the number of channels managed by the mixer.
   If decreasing the number of channels, the upper channels are
   stopped.
 */
int Mix_AllocateChannels(int numchans)
{
    if (numchans<0 || numchans==num_channels)
        return(num_channels);

    if (numchans < num_channels) {
        /* Stop the affected channels */
        int i;
        for(i=numchans; i < num_channels; i++) {
            Mix_UnregisterAllEffects(i);
            Mix_HaltChannel(i);
        }
    }
    Mix_LockAudio();
    mix_channel = (struct _Mix_Channel *) SDL_realloc(mix_channel, numchans * sizeof(struct _Mix_Channel));
    if (numchans > num_channels) {
        /* Initialize the new channels */
        int i;
        for(i=num_channels; i < numchans; i++) {
            mix_channel[i].chunk = NULL;
            mix_channel[i].playing = 0;
            mix_channel[i].looping = 0;
            mix_channel[i].volume = MIX_MAX_VOLUME;
            mix_channel[i].fade_volume = MIX_MAX_VOLUME;
            mix_channel[i].fade_volume_reset = MIX_MAX_VOLUME;
            mix_channel[i].fading = MIX_NO_FADING;
            mix_channel[i].tag = -1;
            mix_channel[i].expire = 0;
            mix_channel[i].effects = NULL;
            mix_channel[i].paused = 0;
        }
    }
    num_channels = numchans;
    Mix_UnlockAudio();
    return(num_channels);
}

/* Return the actual mixer parameters */
int Mix_QuerySpec(int *frequency, Uint16 *format, int *channels)
{
    if (audio_opened) {
        if (frequency) {
            *frequency = mixer.freq;
        }
        if (format) {
            *format = mixer.format;
        }
        if (channels) {
            *channels = mixer.channels;
        }
    }
    return(audio_opened);
}

typedef struct _MusicFragment
{
    Uint8 *data;
    int size;
    struct _MusicFragment *next;
} MusicFragment;

static SDL_AudioSpec *Mix_LoadMusic_RW(Mix_MusicType music_type, SDL_RWops *src, int freesrc, SDL_AudioSpec *spec, Uint8 **audio_buf, Uint32 *audio_len)
{
    int i;
    Mix_MusicInterface *interface = NULL;
    void *music = NULL;
    Sint64 start;
    SDL_bool playing;
    MusicFragment *first = NULL, *last = NULL, *fragment = NULL;
    int count = 0;
    int fragment_size;

    if (!load_music_type(music_type) || !open_music_type(music_type)) {
        return NULL;
    }

    *spec = mixer;

    /* Use fragments sized on full audio frame boundaries - this'll do */
    fragment_size = spec->size;

    start = SDL_RWtell(src);
    for (i = 0; i < get_num_music_interfaces(); ++i) {
        interface = get_music_interface(i);
        if (!interface->opened) {
            continue;
        }
        if (interface->type != music_type) {
            continue;
        }
        if (!interface->CreateFromRW || !interface->GetAudio) {
            continue;
        }

        /* These music interfaces are not safe to use while music is playing */
        if (interface->api == MIX_MUSIC_CMD ||
             interface->api == MIX_MUSIC_MIKMOD ||
             interface->api == MIX_MUSIC_NATIVEMIDI) {
            continue;
        }

        music = interface->CreateFromRW(src, freesrc);
        if (music) {
            /* The interface owns the data source now */
            freesrc = SDL_FALSE;
            break;
        }

        /* Reset the stream for the next decoder */
        SDL_RWseek(src, start, RW_SEEK_SET);
    }

    if (!music) {
        if (freesrc) {
            SDL_RWclose(src);
        }
        Mix_SetError("Unrecognized audio format");
        return NULL;
    }

    Mix_LockAudio();

    if (interface->Play) {
        interface->Play(music, 1);
    }
    playing = SDL_TRUE;

    while (playing) {
        int left;

        fragment = (MusicFragment *)SDL_malloc(sizeof(*fragment));
        if (!fragment) {
            /* Uh oh, out of memory, let's return what we have */
            break;
        }
        fragment->data = (Uint8 *)SDL_malloc(fragment_size);
        if (!fragment->data) {
            /* Uh oh, out of memory, let's return what we have */
            SDL_free(fragment);
            break;
        }
        fragment->next = NULL;

        left = interface->GetAudio(music, fragment->data, fragment_size);
        if (left > 0) {
            playing = SDL_FALSE;
        } else if (interface->IsPlaying) {
            playing = interface->IsPlaying(music);
        }
        fragment->size = (fragment_size - left);

        if (!first) {
            first = fragment;
        }
        if (last) {
            last->next = fragment;
        }
        last = fragment;
        ++count;
    }

    if (interface->Stop) {
        interface->Stop(music);
    }

    if (music) {
        interface->Delete(music);
    }

    Mix_UnlockAudio();

    if (count > 0) {
        *audio_len = (count - 1) * fragment_size + fragment->size;
        *audio_buf = (Uint8 *)SDL_malloc(*audio_len);
        if (*audio_buf) {
            Uint8 *dst = *audio_buf;
            for (fragment = first; fragment; fragment = fragment->next) {
                SDL_memcpy(dst, fragment->data, fragment->size);
                dst += fragment->size;
            }
        } else {
            SDL_OutOfMemory();
            spec = NULL;
        }
    } else {
        Mix_SetError("No audio data");
        spec = NULL;
    }

    while (first) {
        fragment = first;
        first = first->next;
        SDL_free(fragment->data);
        SDL_free(fragment);
    }

    if (freesrc) {
        SDL_RWclose(src);
    }
    return spec;
}

/* Load a wave file */
Mix_Chunk *Mix_LoadWAV_RW(SDL_RWops *src, int freesrc)
{
    Uint8 magic[4];
    Mix_Chunk *chunk;
    SDL_AudioSpec wavespec, *loaded;
    SDL_AudioCVT wavecvt;
    int samplesize;

    /* rcg06012001 Make sure src is valid */
    if (!src) {
        SDL_SetError("Mix_LoadWAV_RW with NULL src");
        return(NULL);
    }

    /* Make sure audio has been opened */
    if (!audio_opened) {
        SDL_SetError("Audio device hasn't been opened");
        if (freesrc) {
            SDL_RWclose(src);
        }
        return(NULL);
    }

    /* Allocate the chunk memory */
    chunk = (Mix_Chunk *)SDL_malloc(sizeof(Mix_Chunk));
    if (chunk == NULL) {
        SDL_SetError("Out of memory");
        if (freesrc) {
            SDL_RWclose(src);
        }
        return(NULL);
    }

    /* Find out what kind of audio file this is */
    if (SDL_RWread(src, magic, 1, 4) != 4) {
        if (freesrc) {
            SDL_RWclose(src);
        }
        Mix_SetError("Couldn't read first 4 bytes of audio data");
        return NULL;
    }
    /* Seek backwards for compatibility with older loaders */
    SDL_RWseek(src, -4, RW_SEEK_CUR);

    if (SDL_memcmp(magic, "WAVE", 4) == 0 || SDL_memcmp(magic, "RIFF", 4) == 0) {
        loaded = SDL_LoadWAV_RW(src, freesrc, &wavespec, (Uint8 **)&chunk->abuf, &chunk->alen);
    } else if (SDL_memcmp(magic, "FORM", 4) == 0) {
        loaded = Mix_LoadAIFF_RW(src, freesrc, &wavespec, (Uint8 **)&chunk->abuf, &chunk->alen);
    } else if (SDL_memcmp(magic, "Crea", 4) == 0) {
        loaded = Mix_LoadVOC_RW(src, freesrc, &wavespec, (Uint8 **)&chunk->abuf, &chunk->alen);
    } else {
        Mix_MusicType music_type = detect_music_type_from_magic(magic);
        loaded = Mix_LoadMusic_RW(music_type, src, freesrc, &wavespec, (Uint8 **)&chunk->abuf, &chunk->alen);
    }
    if (!loaded) {
        /* The individual loaders have closed src if needed */
        SDL_free(chunk);
        return(NULL);
    }

#if 0
    PrintFormat("Audio device", &mixer);
    PrintFormat("-- Wave file", &wavespec);
#endif

    /* Build the audio converter and create conversion buffers */
    if (wavespec.format != mixer.format ||
         wavespec.channels != mixer.channels ||
         wavespec.freq != mixer.freq) {
        if (SDL_BuildAudioCVT(&wavecvt,
                wavespec.format, wavespec.channels, wavespec.freq,
                mixer.format, mixer.channels, mixer.freq) < 0) {
            SDL_free(chunk->abuf);
            SDL_free(chunk);
            return(NULL);
        }
        samplesize = ((wavespec.format & 0xFF)/8)*wavespec.channels;
        wavecvt.len = chunk->alen & ~(samplesize-1);
        wavecvt.buf = (Uint8 *)SDL_calloc(1, wavecvt.len*wavecvt.len_mult);
        if (wavecvt.buf == NULL) {
            SDL_SetError("Out of memory");
            SDL_free(chunk->abuf);
            SDL_free(chunk);
            return(NULL);
        }
        SDL_memcpy(wavecvt.buf, chunk->abuf, wavecvt.len);
        SDL_free(chunk->abuf);

        /* Run the audio converter */
        if (SDL_ConvertAudio(&wavecvt) < 0) {
            SDL_free(wavecvt.buf);
            SDL_free(chunk);
            return(NULL);
        }

        chunk->abuf = wavecvt.buf;
        chunk->alen = wavecvt.len_cvt;
    }

    chunk->allocated = 1;
    chunk->volume = MIX_MAX_VOLUME;

    return(chunk);
}

/* Load a wave file of the mixer format from a memory buffer */
Mix_Chunk *Mix_QuickLoad_WAV(Uint8 *mem)
{
    Mix_Chunk *chunk;
    Uint8 magic[4];

    /* Make sure audio has been opened */
    if (! audio_opened) {
        SDL_SetError("Audio device hasn't been opened");
        return(NULL);
    }

    /* Allocate the chunk memory */
    chunk = (Mix_Chunk *)SDL_calloc(1,sizeof(Mix_Chunk));
    if (chunk == NULL) {
        SDL_SetError("Out of memory");
        return(NULL);
    }

    /* Essentially just skip to the audio data (no error checking - fast) */
    chunk->allocated = 0;
    mem += 12; /* WAV header */
    do {
        SDL_memcpy(magic, mem, 4);
        mem += 4;
        chunk->alen = ((mem[3]<<24)|(mem[2]<<16)|(mem[1]<<8)|(mem[0]));
        mem += 4;
        chunk->abuf = mem;
        mem += chunk->alen;
    } while (memcmp(magic, "data", 4) != 0);
    chunk->volume = MIX_MAX_VOLUME;

    return(chunk);
}

/* Load raw audio data of the mixer format from a memory buffer */
Mix_Chunk *Mix_QuickLoad_RAW(Uint8 *mem, Uint32 len)
{
    Mix_Chunk *chunk;

    /* Make sure audio has been opened */
    if (! audio_opened) {
        SDL_SetError("Audio device hasn't been opened");
        return(NULL);
    }

    /* Allocate the chunk memory */
    chunk = (Mix_Chunk *)SDL_malloc(sizeof(Mix_Chunk));
    if (chunk == NULL) {
        SDL_SetError("Out of memory");
        return(NULL);
    }

    /* Essentially just point at the audio data (no error checking - fast) */
    chunk->allocated = 0;
    chunk->alen = len;
    chunk->abuf = mem;
    chunk->volume = MIX_MAX_VOLUME;

    return(chunk);
}

/* Free an audio chunk previously loaded */
void Mix_FreeChunk(Mix_Chunk *chunk)
{
    int i;

    /* Caution -- if the chunk is playing, the mixer will crash */
    if (chunk) {
        /* Guarantee that this chunk isn't playing */
        Mix_LockAudio();
        if (mix_channel) {
            for (i=0; i<num_channels; ++i) {
                if (chunk == mix_channel[i].chunk) {
                    mix_channel[i].playing = 0;
                    mix_channel[i].looping = 0;
                }
            }
        }
        Mix_UnlockAudio();
        /* Actually free the chunk */
        if (chunk->allocated) {
            SDL_free(chunk->abuf);
        }
        SDL_free(chunk);
    }
}

/* Set a function that is called after all mixing is performed.
   This can be used to provide real-time visual display of the audio stream
   or add a custom mixer filter for the stream data.
*/
void Mix_SetPostMix(void (SDLCALL *mix_func)
                    (void *udata, Uint8 *stream, int len), void *arg)
{
    Mix_LockAudio();
    mix_postmix_data = arg;
    mix_postmix = mix_func;
    Mix_UnlockAudio();
}

/* Add your own music player or mixer function.
   If 'mix_func' is NULL, the default music player is re-enabled.
 */
void Mix_HookMusic(void (SDLCALL *mix_func)(void *udata, Uint8 *stream, int len),
                                                                void *arg)
{
    Mix_LockAudio();
    if (mix_func != NULL) {
        music_data = arg;
        mix_music = mix_func;
    } else {
        music_data = NULL;
        mix_music = music_mixer;
    }
    Mix_UnlockAudio();
}

void *Mix_GetMusicHookData(void)
{
    return(music_data);
}

void Mix_ChannelFinished(void (SDLCALL *channel_finished)(int channel))
{
    Mix_LockAudio();
    channel_done_callback = channel_finished;
    Mix_UnlockAudio();
}


/* Reserve the first channels (0 -> n-1) for the application, i.e. don't allocate
   them dynamically to the next sample if requested with a -1 value below.
   Returns the number of reserved channels.
 */
int Mix_ReserveChannels(int num)
{
    if (num > num_channels)
        num = num_channels;
    reserved_channels = num;
    return num;
}

static int checkchunkintegral(Mix_Chunk *chunk)
{
    int frame_width = 1;

    if ((mixer.format & 0xFF) == 16) frame_width = 2;
    frame_width *= mixer.channels;
    while (chunk->alen % frame_width) chunk->alen--;
    return chunk->alen;
}

/* Play an audio chunk on a specific channel.
   If the specified channel is -1, play on the first free channel.
   'ticks' is the number of milliseconds at most to play the sample, or -1
   if there is no limit.
   Returns which channel was used to play the sound.
*/
int Mix_PlayChannelTimed(int which, Mix_Chunk *chunk, int loops, int ticks)
{
    int i;

    /* Don't play null pointers :-) */
    if (chunk == NULL) {
        Mix_SetError("Tried to play a NULL chunk");
        return(-1);
    }
    if (!checkchunkintegral(chunk)) {
        Mix_SetError("Tried to play a chunk with a bad frame");
        return(-1);
    }

    /* Lock the mixer while modifying the playing channels */
    Mix_LockAudio();
    {
        /* If which is -1, play on the first free channel */
        if (which == -1) {
            for (i=reserved_channels; i<num_channels; ++i) {
                if (mix_channel[i].playing <= 0)
                    break;
            }
            if (i == num_channels) {
                Mix_SetError("No free channels available");
                which = -1;
            } else {
                which = i;
            }
        }

        /* Queue up the audio data for this channel */
        if (which >= 0 && which < num_channels) {
            Uint32 sdl_ticks = SDL_GetTicks();
            if (Mix_Playing(which))
                _Mix_channel_done_playing(which);
            mix_channel[which].samples = chunk->abuf;
            mix_channel[which].playing = chunk->alen;
            mix_channel[which].looping = loops;
            mix_channel[which].chunk = chunk;
            mix_channel[which].paused = 0;
            mix_channel[which].fading = MIX_NO_FADING;
            mix_channel[which].start_time = sdl_ticks;
            mix_channel[which].expire = (ticks>0) ? (sdl_ticks + ticks) : 0;
        }
    }
    Mix_UnlockAudio();

    /* Return the channel on which the sound is being played */
    return(which);
}

/* Change the expiration delay for a channel */
int Mix_ExpireChannel(int which, int ticks)
{
    int status = 0;

    if (which == -1) {
        int i;
        for (i=0; i < num_channels; ++ i) {
            status += Mix_ExpireChannel(i, ticks);
        }
    } else if (which < num_channels) {
        Mix_LockAudio();
        mix_channel[which].expire = (ticks>0) ? (SDL_GetTicks() + ticks) : 0;
        Mix_UnlockAudio();
        ++ status;
    }
    return(status);
}

/* Fade in a sound on a channel, over ms milliseconds */
int Mix_FadeInChannelTimed(int which, Mix_Chunk *chunk, int loops, int ms, int ticks)
{
    int i;

    /* Don't play null pointers :-) */
    if (chunk == NULL) {
        return(-1);
    }
    if (!checkchunkintegral(chunk)) {
        Mix_SetError("Tried to play a chunk with a bad frame");
        return(-1);
    }

    /* Lock the mixer while modifying the playing channels */
    Mix_LockAudio();
    {
        /* If which is -1, play on the first free channel */
        if (which == -1) {
            for (i=reserved_channels; i<num_channels; ++i) {
                if (mix_channel[i].playing <= 0)
                    break;
            }
            if (i == num_channels) {
                which = -1;
            } else {
                which = i;
            }
        }

        /* Queue up the audio data for this channel */
        if (which >= 0 && which < num_channels) {
            Uint32 sdl_ticks = SDL_GetTicks();
            if (Mix_Playing(which))
                _Mix_channel_done_playing(which);
            mix_channel[which].samples = chunk->abuf;
            mix_channel[which].playing = chunk->alen;
            mix_channel[which].looping = loops;
            mix_channel[which].chunk = chunk;
            mix_channel[which].paused = 0;
            mix_channel[which].fading = MIX_FADING_IN;
            mix_channel[which].fade_volume = mix_channel[which].volume;
            mix_channel[which].fade_volume_reset = mix_channel[which].volume;
            mix_channel[which].volume = 0;
            mix_channel[which].fade_length = (Uint32)ms;
            mix_channel[which].start_time = mix_channel[which].ticks_fade = sdl_ticks;
            mix_channel[which].expire = (ticks > 0) ? (sdl_ticks+ticks) : 0;
        }
    }
    Mix_UnlockAudio();

    /* Return the channel on which the sound is being played */
    return(which);
}

/* Set volume of a particular channel */
int Mix_Volume(int which, int volume)
{
    int i;
    int prev_volume = 0;

    if (which == -1) {
        for (i=0; i<num_channels; ++i) {
            prev_volume += Mix_Volume(i, volume);
        }
        prev_volume /= num_channels;
    } else if (which < num_channels) {
        prev_volume = mix_channel[which].volume;
        if (volume >= 0) {
            if (volume > MIX_MAX_VOLUME) {
                volume = MIX_MAX_VOLUME;
            }
            mix_channel[which].volume = volume;
        }
    }
    return(prev_volume);
}
/* Set volume of a particular chunk */
int Mix_VolumeChunk(Mix_Chunk *chunk, int volume)
{
    int prev_volume;

    prev_volume = chunk->volume;
    if (volume >= 0) {
        if (volume > MIX_MAX_VOLUME) {
            volume = MIX_MAX_VOLUME;
        }
        chunk->volume = volume;
    }
    return(prev_volume);
}

/* Halt playing of a particular channel */
int Mix_HaltChannel(int which)
{
    int i;

    if (which == -1) {
        for (i=0; i<num_channels; ++i) {
            Mix_HaltChannel(i);
        }
    } else if (which < num_channels) {
        Mix_LockAudio();
        if (mix_channel[which].playing) {
            _Mix_channel_done_playing(which);
            mix_channel[which].playing = 0;
            mix_channel[which].looping = 0;
        }
        mix_channel[which].expire = 0;
        if(mix_channel[which].fading != MIX_NO_FADING) /* Restore volume */
            mix_channel[which].volume = mix_channel[which].fade_volume_reset;
        mix_channel[which].fading = MIX_NO_FADING;
        Mix_UnlockAudio();
    }
    return(0);
}

/* Halt playing of a particular group of channels */
int Mix_HaltGroup(int tag)
{
    int i;

    for (i=0; i<num_channels; ++i) {
        if(mix_channel[i].tag == tag) {
            Mix_HaltChannel(i);
        }
    }
    return(0);
}

/* Fade out a channel and then stop it automatically */
int Mix_FadeOutChannel(int which, int ms)
{
    int status;

    status = 0;
    if (audio_opened) {
        if (which == -1) {
            int i;

            for (i=0; i<num_channels; ++i) {
                status += Mix_FadeOutChannel(i, ms);
            }
        } else if (which < num_channels) {
            Mix_LockAudio();
            if (mix_channel[which].playing &&
                (mix_channel[which].volume > 0) &&
                (mix_channel[which].fading != MIX_FADING_OUT)) {
                mix_channel[which].fade_volume = mix_channel[which].volume;
                mix_channel[which].fading = MIX_FADING_OUT;
                mix_channel[which].fade_length = (Uint32)ms;
                mix_channel[which].ticks_fade = SDL_GetTicks();

                /* only change fade_volume_reset if we're not fading. */
                if (mix_channel[which].fading == MIX_NO_FADING) {
                    mix_channel[which].fade_volume_reset = mix_channel[which].volume;
                }
                ++status;
            }
            Mix_UnlockAudio();
        }
    }
    return(status);
}

/* Halt playing of a particular group of channels */
int Mix_FadeOutGroup(int tag, int ms)
{
    int i;
    int status = 0;
    for (i=0; i<num_channels; ++i) {
        if(mix_channel[i].tag == tag) {
            status += Mix_FadeOutChannel(i,ms);
        }
    }
    return(status);
}

Mix_Fading Mix_FadingChannel(int which)
{
    if (which < 0 || which >= num_channels) {
        return MIX_NO_FADING;
    }
    return mix_channel[which].fading;
}

/* Check the status of a specific channel.
   If the specified mix_channel is -1, check all mix channels.
*/
int Mix_Playing(int which)
{
    int status;

    status = 0;
    if (which == -1) {
        int i;

        for (i=0; i<num_channels; ++i) {
            if ((mix_channel[i].playing > 0) ||
                mix_channel[i].looping)
            {
                ++status;
            }
        }
    } else if (which < num_channels) {
        if ((mix_channel[which].playing > 0) ||
             mix_channel[which].looping)
        {
            ++status;
        }
    }
    return(status);
}

/* rcg06072001 Get the chunk associated with a channel. */
Mix_Chunk *Mix_GetChunk(int channel)
{
    Mix_Chunk *retval = NULL;

    if ((channel >= 0) && (channel < num_channels)) {
        retval = mix_channel[channel].chunk;
    }

    return(retval);
}

/* Close the mixer, halting all playing audio */
void Mix_CloseAudio(void)
{
    int i;

    if (audio_opened) {
        if (audio_opened == 1) {
            for (i = 0; i < num_channels; i++) {
                Mix_UnregisterAllEffects(i);
            }
            Mix_UnregisterAllEffects(MIX_CHANNEL_POST);
            close_music();
            Mix_SetMusicCMD(NULL);
            Mix_HaltChannel(-1);
            _Mix_DeinitEffects();
            SDL_CloseAudioDevice(audio_device);
            audio_device = 0;
            SDL_free(mix_channel);
            mix_channel = NULL;

            /* rcg06042009 report available decoders at runtime. */
            SDL_free((void *)chunk_decoders);
            chunk_decoders = NULL;
            num_decoders = 0;
        }
        --audio_opened;
    }
}

/* Pause a particular channel (or all) */
void Mix_Pause(int which)
{
    Uint32 sdl_ticks = SDL_GetTicks();
    if (which == -1) {
        int i;

        for (i=0; i<num_channels; ++i) {
            if (mix_channel[i].playing > 0) {
                mix_channel[i].paused = sdl_ticks;
            }
        }
    } else if (which < num_channels) {
        if (mix_channel[which].playing > 0) {
            mix_channel[which].paused = sdl_ticks;
        }
    }
}

/* Resume a paused channel */
void Mix_Resume(int which)
{
    Uint32 sdl_ticks = SDL_GetTicks();

    Mix_LockAudio();
    if (which == -1) {
        int i;

        for (i=0; i<num_channels; ++i) {
            if (mix_channel[i].playing > 0) {
                if(mix_channel[i].expire > 0)
                    mix_channel[i].expire += sdl_ticks - mix_channel[i].paused;
                mix_channel[i].paused = 0;
            }
        }
    } else if (which < num_channels) {
        if (mix_channel[which].playing > 0) {
            if(mix_channel[which].expire > 0)
                mix_channel[which].expire += sdl_ticks - mix_channel[which].paused;
            mix_channel[which].paused = 0;
        }
    }
    Mix_UnlockAudio();
}

int Mix_Paused(int which)
{
    if (which < 0) {
        int status = 0;
        int i;
        for(i=0; i < num_channels; ++i) {
            if (mix_channel[i].paused) {
                ++ status;
            }
        }
        return(status);
    } else if (which < num_channels) {
        return(mix_channel[which].paused != 0);
    } else {
        return(0);
    }
}

/* Change the group of a channel */
int Mix_GroupChannel(int which, int tag)
{
    if (which < 0 || which > num_channels)
        return(0);

    Mix_LockAudio();
    mix_channel[which].tag = tag;
    Mix_UnlockAudio();
    return(1);
}

/* Assign several consecutive channels to a group */
int Mix_GroupChannels(int from, int to, int tag)
{
    int status = 0;
    for(; from <= to; ++ from) {
        status += Mix_GroupChannel(from, tag);
    }
    return(status);
}

/* Finds the first available channel in a group of channels */
int Mix_GroupAvailable(int tag)
{
    int i;
    for(i=0; i < num_channels; i ++) {
        if (((tag == -1) || (tag == mix_channel[i].tag)) &&
                            (mix_channel[i].playing <= 0))
            return i;
    }
    return(-1);
}

int Mix_GroupCount(int tag)
{
    int count = 0;
    int i;
    for(i=0; i < num_channels; i ++) {
        if (mix_channel[i].tag==tag || tag==-1)
            ++ count;
    }
    return(count);
}

/* Finds the "oldest" sample playing in a group of channels */
int Mix_GroupOldest(int tag)
{
    int chan = -1;
    Uint32 mintime = SDL_GetTicks();
    int i;
    for(i=0; i < num_channels; i ++) {
        if ((mix_channel[i].tag==tag || tag==-1) && mix_channel[i].playing > 0
             && mix_channel[i].start_time <= mintime) {
            mintime = mix_channel[i].start_time;
            chan = i;
        }
    }
    return(chan);
}

/* Finds the "most recent" (i.e. last) sample playing in a group of channels */
int Mix_GroupNewer(int tag)
{
    int chan = -1;
    Uint32 maxtime = 0;
    int i;
    for(i=0; i < num_channels; i ++) {
        if ((mix_channel[i].tag==tag || tag==-1) && mix_channel[i].playing > 0
             && mix_channel[i].start_time >= maxtime) {
            maxtime = mix_channel[i].start_time;
            chan = i;
        }
    }
    return(chan);
}



/*
 * rcg06122001 The special effects exportable API.
 *  Please see effect_*.c for internally-implemented effects, such
 *  as Mix_SetPanning().
 */

/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
static int _Mix_register_effect(effect_info **e, Mix_EffectFunc_t f,
                Mix_EffectDone_t d, void *arg)
{
    effect_info *new_e;

    if (!e) {
        Mix_SetError("Internal error");
        return(0);
    }

    if (f == NULL) {
        Mix_SetError("NULL effect callback");
        return(0);
    }

    new_e = SDL_malloc(sizeof (effect_info));
    if (new_e == NULL) {
        Mix_SetError("Out of memory");
        return(0);
    }

    new_e->callback = f;
    new_e->done_callback = d;
    new_e->udata = arg;
    new_e->next = NULL;

    /* add new effect to end of linked list... */
    if (*e == NULL) {
        *e = new_e;
    } else {
        effect_info *cur = *e;
        while (1) {
            if (cur->next == NULL) {
                cur->next = new_e;
                break;
            }
            cur = cur->next;
        }
    }

    return(1);
}


/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
static int _Mix_remove_effect(int channel, effect_info **e, Mix_EffectFunc_t f)
{
    effect_info *cur;
    effect_info *prev = NULL;
    effect_info *next = NULL;

    if (!e) {
        Mix_SetError("Internal error");
        return(0);
    }

    for (cur = *e; cur != NULL; cur = cur->next) {
        if (cur->callback == f) {
            next = cur->next;
            if (cur->done_callback != NULL) {
                cur->done_callback(channel, cur->udata);
            }
            SDL_free(cur);

            if (prev == NULL) {   /* removing first item of list? */
                *e = next;
            } else {
                prev->next = next;
            }
            return(1);
        }
        prev = cur;
    }

    Mix_SetError("No such effect registered");
    return(0);
}


/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
static int _Mix_remove_all_effects(int channel, effect_info **e)
{
    effect_info *cur;
    effect_info *next;

    if (!e) {
        Mix_SetError("Internal error");
        return(0);
    }

    for (cur = *e; cur != NULL; cur = next) {
        next = cur->next;
        if (cur->done_callback != NULL) {
            cur->done_callback(channel, cur->udata);
        }
        SDL_free(cur);
    }
    *e = NULL;

    return(1);
}


/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
int _Mix_RegisterEffect_locked(int channel, Mix_EffectFunc_t f,
            Mix_EffectDone_t d, void *arg)
{
    effect_info **e = NULL;

    if (channel == MIX_CHANNEL_POST) {
        e = &posteffects;
    } else {
        if ((channel < 0) || (channel >= num_channels)) {
            Mix_SetError("Invalid channel number");
            return(0);
        }
        e = &mix_channel[channel].effects;
    }

    return _Mix_register_effect(e, f, d, arg);
}

int Mix_RegisterEffect(int channel, Mix_EffectFunc_t f,
            Mix_EffectDone_t d, void *arg)
{
    int retval;
    Mix_LockAudio();
    retval = _Mix_RegisterEffect_locked(channel, f, d, arg);
    Mix_UnlockAudio();
    return retval;
}


/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
int _Mix_UnregisterEffect_locked(int channel, Mix_EffectFunc_t f)
{
    effect_info **e = NULL;

    if (channel == MIX_CHANNEL_POST) {
        e = &posteffects;
    } else {
        if ((channel < 0) || (channel >= num_channels)) {
            Mix_SetError("Invalid channel number");
            return(0);
        }
        e = &mix_channel[channel].effects;
    }

    return _Mix_remove_effect(channel, e, f);
}

int Mix_UnregisterEffect(int channel, Mix_EffectFunc_t f)
{
    int retval;
    Mix_LockAudio();
    retval = _Mix_UnregisterEffect_locked(channel, f);
    Mix_UnlockAudio();
    return(retval);
}

/* MAKE SURE you hold the audio lock (Mix_LockAudio()) before calling this! */
int _Mix_UnregisterAllEffects_locked(int channel)
{
    effect_info **e = NULL;

    if (channel == MIX_CHANNEL_POST) {
        e = &posteffects;
    } else {
        if ((channel < 0) || (channel >= num_channels)) {
            Mix_SetError("Invalid channel number");
            return(0);
        }
        e = &mix_channel[channel].effects;
    }

    return _Mix_remove_all_effects(channel, e);
}

int Mix_UnregisterAllEffects(int channel)
{
    int retval;
    Mix_LockAudio();
    retval = _Mix_UnregisterAllEffects_locked(channel);
    Mix_UnlockAudio();
    return(retval);
}

void Mix_LockAudio(void)
{
    SDL_LockAudioDevice(audio_device);
}

void Mix_UnlockAudio(void)
{
    SDL_UnlockAudioDevice(audio_device);
}

/* end of mixer.c ... */

/* vi: set ts=4 sw=4 expandtab: */