src/audio/dsp/SDL_dspaudio.c
author Ryan C. Gordon
Tue, 24 Jan 2017 16:18:25 -0500
changeset 10850 c9dc0068b0e7
parent 10737 3406a0f8b041
child 11811 5d94cb6b24d3
permissions -rw-r--r--
configure: report libsamplerate support status.
slouken@0
     1
/*
slouken@5535
     2
  Simple DirectMedia Layer
slouken@10737
     3
  Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
slouken@0
     4
slouken@5535
     5
  This software is provided 'as-is', without any express or implied
slouken@5535
     6
  warranty.  In no event will the authors be held liable for any damages
slouken@5535
     7
  arising from the use of this software.
slouken@0
     8
slouken@5535
     9
  Permission is granted to anyone to use this software for any purpose,
slouken@5535
    10
  including commercial applications, and to alter it and redistribute it
slouken@5535
    11
  freely, subject to the following restrictions:
slouken@0
    12
slouken@5535
    13
  1. The origin of this software must not be misrepresented; you must not
slouken@5535
    14
     claim that you wrote the original software. If you use this software
slouken@5535
    15
     in a product, an acknowledgment in the product documentation would be
slouken@5535
    16
     appreciated but is not required.
slouken@5535
    17
  2. Altered source versions must be plainly marked as such, and must not be
slouken@5535
    18
     misrepresented as being the original software.
slouken@5535
    19
  3. This notice may not be removed or altered from any source distribution.
slouken@0
    20
*/
icculus@8093
    21
#include "../../SDL_internal.h"
slouken@0
    22
slouken@6044
    23
#if SDL_AUDIO_DRIVER_OSS
slouken@6044
    24
slouken@0
    25
/* Allow access to a raw mixing buffer */
slouken@0
    26
slouken@1895
    27
#include <stdio.h>              /* For perror() */
slouken@1895
    28
#include <string.h>             /* For strerror() */
slouken@0
    29
#include <errno.h>
slouken@0
    30
#include <unistd.h>
slouken@0
    31
#include <fcntl.h>
slouken@0
    32
#include <signal.h>
slouken@0
    33
#include <sys/time.h>
slouken@0
    34
#include <sys/ioctl.h>
slouken@0
    35
#include <sys/stat.h>
slouken@1361
    36
slouken@1361
    37
#if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H
slouken@94
    38
/* This is installed on some systems */
slouken@94
    39
#include <soundcard.h>
slouken@94
    40
#else
slouken@94
    41
/* This is recommended by OSS */
slouken@0
    42
#include <sys/soundcard.h>
slouken@94
    43
#endif
slouken@0
    44
slouken@1358
    45
#include "SDL_timer.h"
slouken@0
    46
#include "SDL_audio.h"
slouken@1361
    47
#include "../SDL_audio_c.h"
slouken@1361
    48
#include "../SDL_audiodev_c.h"
slouken@0
    49
#include "SDL_dspaudio.h"
slouken@0
    50
icculus@2049
    51
icculus@2049
    52
static void
icculus@9394
    53
DSP_DetectDevices(void)
slouken@0
    54
{
icculus@9394
    55
    SDL_EnumUnixAudioDevices(0, NULL);
slouken@0
    56
}
slouken@0
    57
icculus@2049
    58
slouken@1895
    59
static void
icculus@2049
    60
DSP_CloseDevice(_THIS)
slouken@0
    61
{
icculus@10255
    62
    if (this->hidden->audio_fd >= 0) {
icculus@10255
    63
        close(this->hidden->audio_fd);
slouken@1895
    64
    }
icculus@10256
    65
    SDL_free(this->hidden->mixbuf);
icculus@10255
    66
    SDL_free(this->hidden);
slouken@0
    67
}
slouken@0
    68
icculus@2049
    69
slouken@1895
    70
static int
icculus@9394
    71
DSP_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
slouken@0
    72
{
icculus@2049
    73
    const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);
slouken@1895
    74
    int format;
slouken@1895
    75
    int value;
slouken@1895
    76
    int frag_spec;
icculus@1982
    77
    SDL_AudioFormat test_format;
slouken@0
    78
icculus@2049
    79
    /* We don't care what the devname is...we'll try to open anything. */
icculus@2049
    80
    /*  ...but default to first name in the list... */
icculus@2049
    81
    if (devname == NULL) {
icculus@5593
    82
        devname = SDL_GetAudioDeviceName(0, iscapture);
icculus@5593
    83
        if (devname == NULL) {
icculus@7038
    84
            return SDL_SetError("No such audio device");
icculus@2049
    85
        }
icculus@2049
    86
    }
icculus@2049
    87
icculus@2071
    88
    /* Make sure fragment size stays a power of 2, or OSS fails. */
icculus@2071
    89
    /* I don't know which of these are actually legal values, though... */
icculus@2071
    90
    if (this->spec.channels > 8)
icculus@2071
    91
        this->spec.channels = 8;
icculus@2071
    92
    else if (this->spec.channels > 4)
icculus@2071
    93
        this->spec.channels = 4;
icculus@2071
    94
    else if (this->spec.channels > 2)
icculus@2071
    95
        this->spec.channels = 2;
icculus@2071
    96
icculus@2049
    97
    /* Initialize all variables that we clean on shutdown */
icculus@2049
    98
    this->hidden = (struct SDL_PrivateAudioData *)
slouken@2060
    99
        SDL_malloc((sizeof *this->hidden));
icculus@2049
   100
    if (this->hidden == NULL) {
icculus@7038
   101
        return SDL_OutOfMemory();
icculus@2049
   102
    }
icculus@10257
   103
    SDL_zerop(this->hidden);
icculus@2049
   104
slouken@1895
   105
    /* Open the audio device */
icculus@2049
   106
    this->hidden->audio_fd = open(devname, flags, 0);
icculus@2049
   107
    if (this->hidden->audio_fd < 0) {
icculus@7038
   108
        return SDL_SetError("Couldn't open %s: %s", devname, strerror(errno));
slouken@1895
   109
    }
slouken@968
   110
icculus@10269
   111
    /* Make the file descriptor use blocking i/o with fcntl() */
slouken@1895
   112
    {
icculus@2049
   113
        long ctlflags;
icculus@2049
   114
        ctlflags = fcntl(this->hidden->audio_fd, F_GETFL);
icculus@2049
   115
        ctlflags &= ~O_NONBLOCK;
icculus@2049
   116
        if (fcntl(this->hidden->audio_fd, F_SETFL, ctlflags) < 0) {
icculus@7038
   117
            return SDL_SetError("Couldn't set audio blocking mode");
slouken@1895
   118
        }
slouken@1895
   119
    }
slouken@968
   120
slouken@1895
   121
    /* Get a list of supported hardware formats */
icculus@2049
   122
    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0) {
slouken@1895
   123
        perror("SNDCTL_DSP_GETFMTS");
icculus@7038
   124
        return SDL_SetError("Couldn't get audio format list");
slouken@1895
   125
    }
slouken@968
   126
slouken@1895
   127
    /* Try for a closest match on audio format */
slouken@1895
   128
    format = 0;
icculus@2049
   129
    for (test_format = SDL_FirstAudioFormat(this->spec.format);
slouken@1895
   130
         !format && test_format;) {
slouken@968
   131
#ifdef DEBUG_AUDIO
slouken@1895
   132
        fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
slouken@968
   133
#endif
slouken@1895
   134
        switch (test_format) {
slouken@1895
   135
        case AUDIO_U8:
slouken@1895
   136
            if (value & AFMT_U8) {
slouken@1895
   137
                format = AFMT_U8;
slouken@1895
   138
            }
slouken@1895
   139
            break;
slouken@1895
   140
        case AUDIO_S16LSB:
slouken@1895
   141
            if (value & AFMT_S16_LE) {
slouken@1895
   142
                format = AFMT_S16_LE;
slouken@1895
   143
            }
slouken@1895
   144
            break;
slouken@1895
   145
        case AUDIO_S16MSB:
slouken@1895
   146
            if (value & AFMT_S16_BE) {
slouken@1895
   147
                format = AFMT_S16_BE;
slouken@1895
   148
            }
slouken@1895
   149
            break;
slouken@968
   150
#if 0
slouken@968
   151
/*
slouken@7191
   152
 * These formats are not used by any real life systems so they are not
slouken@968
   153
 * needed here.
slouken@968
   154
 */
slouken@1895
   155
        case AUDIO_S8:
slouken@1895
   156
            if (value & AFMT_S8) {
slouken@1895
   157
                format = AFMT_S8;
slouken@1895
   158
            }
slouken@1895
   159
            break;
slouken@1895
   160
        case AUDIO_U16LSB:
slouken@1895
   161
            if (value & AFMT_U16_LE) {
slouken@1895
   162
                format = AFMT_U16_LE;
slouken@1895
   163
            }
slouken@1895
   164
            break;
slouken@1895
   165
        case AUDIO_U16MSB:
slouken@1895
   166
            if (value & AFMT_U16_BE) {
slouken@1895
   167
                format = AFMT_U16_BE;
slouken@1895
   168
            }
slouken@1895
   169
            break;
slouken@968
   170
#endif
slouken@1895
   171
        default:
slouken@1895
   172
            format = 0;
slouken@1895
   173
            break;
slouken@1895
   174
        }
slouken@1895
   175
        if (!format) {
slouken@1895
   176
            test_format = SDL_NextAudioFormat();
slouken@1895
   177
        }
slouken@1895
   178
    }
slouken@1895
   179
    if (format == 0) {
icculus@7038
   180
        return SDL_SetError("Couldn't find any hardware audio formats");
slouken@1895
   181
    }
icculus@2049
   182
    this->spec.format = test_format;
slouken@968
   183
slouken@1895
   184
    /* Set the audio format */
slouken@1895
   185
    value = format;
slouken@2060
   186
    if ((ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
slouken@2060
   187
        (value != format)) {
slouken@1895
   188
        perror("SNDCTL_DSP_SETFMT");
icculus@7038
   189
        return SDL_SetError("Couldn't set audio format");
slouken@1895
   190
    }
slouken@968
   191
slouken@1895
   192
    /* Set the number of channels of output */
icculus@2049
   193
    value = this->spec.channels;
icculus@2049
   194
    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0) {
slouken@1895
   195
        perror("SNDCTL_DSP_CHANNELS");
icculus@7038
   196
        return SDL_SetError("Cannot set the number of channels");
slouken@1895
   197
    }
icculus@2049
   198
    this->spec.channels = value;
slouken@968
   199
slouken@1895
   200
    /* Set the DSP frequency */
icculus@2049
   201
    value = this->spec.freq;
icculus@2049
   202
    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SPEED, &value) < 0) {
slouken@1895
   203
        perror("SNDCTL_DSP_SPEED");
icculus@7038
   204
        return SDL_SetError("Couldn't set audio frequency");
slouken@1895
   205
    }
icculus@2049
   206
    this->spec.freq = value;
slouken@0
   207
slouken@1895
   208
    /* Calculate the final parameters for this audio specification */
icculus@2049
   209
    SDL_CalculateAudioSpec(&this->spec);
slouken@0
   210
slouken@1895
   211
    /* Determine the power of two of the fragment size */
icculus@2049
   212
    for (frag_spec = 0; (0x01U << frag_spec) < this->spec.size; ++frag_spec);
icculus@2049
   213
    if ((0x01U << frag_spec) != this->spec.size) {
icculus@7038
   214
        return SDL_SetError("Fragment size must be a power of two");
slouken@1895
   215
    }
slouken@1895
   216
    frag_spec |= 0x00020000;    /* two fragments, for low latency */
slouken@0
   217
slouken@1895
   218
    /* Set the audio buffering parameters */
slouken@0
   219
#ifdef DEBUG_AUDIO
slouken@1895
   220
    fprintf(stderr, "Requesting %d fragments of size %d\n",
slouken@1895
   221
            (frag_spec >> 16), 1 << (frag_spec & 0xFFFF));
slouken@0
   222
#endif
icculus@2049
   223
    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0) {
slouken@1895
   224
        perror("SNDCTL_DSP_SETFRAGMENT");
slouken@1895
   225
    }
slouken@0
   226
#ifdef DEBUG_AUDIO
slouken@1895
   227
    {
slouken@1895
   228
        audio_buf_info info;
icculus@2049
   229
        ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETOSPACE, &info);
slouken@1895
   230
        fprintf(stderr, "fragments = %d\n", info.fragments);
slouken@1895
   231
        fprintf(stderr, "fragstotal = %d\n", info.fragstotal);
slouken@1895
   232
        fprintf(stderr, "fragsize = %d\n", info.fragsize);
slouken@1895
   233
        fprintf(stderr, "bytes = %d\n", info.bytes);
slouken@1895
   234
    }
slouken@0
   235
#endif
slouken@0
   236
slouken@1895
   237
    /* Allocate mixing buffer */
icculus@10269
   238
    if (!iscapture) {
icculus@10269
   239
        this->hidden->mixlen = this->spec.size;
icculus@10269
   240
        this->hidden->mixbuf = (Uint8 *) SDL_malloc(this->hidden->mixlen);
icculus@10269
   241
        if (this->hidden->mixbuf == NULL) {
icculus@10269
   242
            return SDL_OutOfMemory();
icculus@10269
   243
        }
icculus@10269
   244
        SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
slouken@1895
   245
    }
slouken@0
   246
slouken@1895
   247
    /* We're ready to rock and roll. :-) */
icculus@7038
   248
    return 0;
icculus@2049
   249
}
icculus@2049
   250
icculus@2049
   251
icculus@2049
   252
static void
icculus@2049
   253
DSP_PlayDevice(_THIS)
icculus@2049
   254
{
icculus@10269
   255
    struct SDL_PrivateAudioData *h = this->hidden;
icculus@10269
   256
    if (write(h->audio_fd, h->mixbuf, h->mixlen) == -1) {
icculus@2049
   257
        perror("Audio write");
icculus@9394
   258
        SDL_OpenedAudioDeviceDisconnected(this);
icculus@2049
   259
    }
icculus@2049
   260
#ifdef DEBUG_AUDIO
icculus@10269
   261
    fprintf(stderr, "Wrote %d bytes of audio data\n", h->mixlen);
icculus@2049
   262
#endif
slouken@0
   263
}
slouken@1895
   264
icculus@2049
   265
static Uint8 *
icculus@2049
   266
DSP_GetDeviceBuf(_THIS)
icculus@2049
   267
{
icculus@2049
   268
    return (this->hidden->mixbuf);
icculus@2049
   269
}
icculus@2049
   270
icculus@2049
   271
static int
icculus@10269
   272
DSP_CaptureFromDevice(_THIS, void *buffer, int buflen)
icculus@10269
   273
{
icculus@10269
   274
    return (int) read(this->hidden->audio_fd, buffer, buflen);
icculus@10269
   275
}
icculus@10269
   276
icculus@10269
   277
static void
icculus@10269
   278
DSP_FlushCapture(_THIS)
icculus@10269
   279
{
icculus@10269
   280
    struct SDL_PrivateAudioData *h = this->hidden;
icculus@10269
   281
    audio_buf_info info;
icculus@10269
   282
    if (ioctl(h->audio_fd, SNDCTL_DSP_GETISPACE, &info) == 0) {
icculus@10269
   283
        while (info.bytes > 0) {
icculus@10269
   284
            char buf[512];
icculus@10269
   285
            const size_t len = SDL_min(sizeof (buf), info.bytes);
icculus@10269
   286
            const ssize_t br = read(h->audio_fd, buf, len);
icculus@10269
   287
            if (br <= 0) {
icculus@10269
   288
                break;
icculus@10269
   289
            }
icculus@10269
   290
            info.bytes -= br;
icculus@10269
   291
        }
icculus@10269
   292
    }
icculus@10269
   293
}
icculus@10269
   294
icculus@10269
   295
static int
slouken@2060
   296
DSP_Init(SDL_AudioDriverImpl * impl)
icculus@2049
   297
{
icculus@2049
   298
    /* Set the function pointers */
icculus@2049
   299
    impl->DetectDevices = DSP_DetectDevices;
icculus@2049
   300
    impl->OpenDevice = DSP_OpenDevice;
icculus@2049
   301
    impl->PlayDevice = DSP_PlayDevice;
icculus@2049
   302
    impl->GetDeviceBuf = DSP_GetDeviceBuf;
icculus@2049
   303
    impl->CloseDevice = DSP_CloseDevice;
icculus@10269
   304
    impl->CaptureFromDevice = DSP_CaptureFromDevice;
icculus@10269
   305
    impl->FlushCapture = DSP_FlushCapture;
icculus@2049
   306
icculus@9394
   307
    impl->AllowsArbitraryDeviceNames = 1;
icculus@10269
   308
    impl->HasCaptureSupport = SDL_TRUE;
icculus@9394
   309
icculus@3699
   310
    return 1;   /* this audio target is available. */
icculus@2049
   311
}
icculus@2049
   312
icculus@2049
   313
icculus@2049
   314
AudioBootStrap DSP_bootstrap = {
icculus@5594
   315
    "dsp", "OSS /dev/dsp standard audio", DSP_Init, 0
icculus@2049
   316
};
icculus@2049
   317
slouken@6044
   318
#endif /* SDL_AUDIO_DRIVER_OSS */
slouken@6044
   319
slouken@1895
   320
/* vi: set ts=4 sw=4 expandtab: */