SDL_dspaudio.c
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2016 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.
*/
#include "../../SDL_internal.h"
#if SDL_AUDIO_DRIVER_OSS
/* Allow access to a raw mixing buffer */
#include <stdio.h> /* For perror() */
#include <string.h> /* For strerror() */
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H
/* This is installed on some systems */
#include <soundcard.h>
#else
/* This is recommended by OSS */
#include <sys/soundcard.h>
#endif
#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "../SDL_audiodev_c.h"
#include "SDL_dspaudio.h"
static void
DSP_DetectDevices(void)
{
SDL_EnumUnixAudioDevices(0, NULL);
}
static void
DSP_CloseDevice(_THIS)
{
if (this->hidden != NULL) {
SDL_FreeAudioMem(this->hidden->mixbuf);
this->hidden->mixbuf = NULL;
if (this->hidden->audio_fd >= 0) {
close(this->hidden->audio_fd);
this->hidden->audio_fd = -1;
}
SDL_free(this->hidden);
this->hidden = NULL;
}
}
static int
DSP_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
{
const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);
int format;
int value;
int frag_spec;
SDL_AudioFormat test_format;
/* We don't care what the devname is...we'll try to open anything. */
/* ...but default to first name in the list... */
if (devname == NULL) {
devname = SDL_GetAudioDeviceName(0, iscapture);
if (devname == NULL) {
return SDL_SetError("No such audio device");
}
}
/* Make sure fragment size stays a power of 2, or OSS fails. */
/* I don't know which of these are actually legal values, though... */
if (this->spec.channels > 8)
this->spec.channels = 8;
else if (this->spec.channels > 4)
this->spec.channels = 4;
else if (this->spec.channels > 2)
this->spec.channels = 2;
/* Initialize all variables that we clean on shutdown */
this->hidden = (struct SDL_PrivateAudioData *)
SDL_malloc((sizeof *this->hidden));
if (this->hidden == NULL) {
return SDL_OutOfMemory();
}
SDL_memset(this->hidden, 0, (sizeof *this->hidden));
/* Open the audio device */
this->hidden->audio_fd = open(devname, flags, 0);
if (this->hidden->audio_fd < 0) {
DSP_CloseDevice(this);
return SDL_SetError("Couldn't open %s: %s", devname, strerror(errno));
}
this->hidden->mixbuf = NULL;
/* Make the file descriptor use blocking writes with fcntl() */
{
long ctlflags;
ctlflags = fcntl(this->hidden->audio_fd, F_GETFL);
ctlflags &= ~O_NONBLOCK;
if (fcntl(this->hidden->audio_fd, F_SETFL, ctlflags) < 0) {
DSP_CloseDevice(this);
return SDL_SetError("Couldn't set audio blocking mode");
}
}
/* Get a list of supported hardware formats */
if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0) {
perror("SNDCTL_DSP_GETFMTS");
DSP_CloseDevice(this);
return SDL_SetError("Couldn't get audio format list");
}
/* Try for a closest match on audio format */
format = 0;
for (test_format = SDL_FirstAudioFormat(this->spec.format);
!format && test_format;) {
#ifdef DEBUG_AUDIO
fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
#endif
switch (test_format) {
case AUDIO_U8:
if (value & AFMT_U8) {
format = AFMT_U8;
}
break;
case AUDIO_S16LSB:
if (value & AFMT_S16_LE) {
format = AFMT_S16_LE;
}
break;
case AUDIO_S16MSB:
if (value & AFMT_S16_BE) {
format = AFMT_S16_BE;
}
break;
#if 0
/*
* These formats are not used by any real life systems so they are not
* needed here.
*/
case AUDIO_S8:
if (value & AFMT_S8) {
format = AFMT_S8;
}
break;
case AUDIO_U16LSB:
if (value & AFMT_U16_LE) {
format = AFMT_U16_LE;
}
break;
case AUDIO_U16MSB:
if (value & AFMT_U16_BE) {
format = AFMT_U16_BE;
}
break;
#endif
default:
format = 0;
break;
}
if (!format) {
test_format = SDL_NextAudioFormat();
}
}
if (format == 0) {
DSP_CloseDevice(this);
return SDL_SetError("Couldn't find any hardware audio formats");
}
this->spec.format = test_format;
/* Set the audio format */
value = format;
if ((ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
(value != format)) {
perror("SNDCTL_DSP_SETFMT");
DSP_CloseDevice(this);
return SDL_SetError("Couldn't set audio format");
}
/* Set the number of channels of output */
value = this->spec.channels;
if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0) {
perror("SNDCTL_DSP_CHANNELS");
DSP_CloseDevice(this);
return SDL_SetError("Cannot set the number of channels");
}
this->spec.channels = value;
/* Set the DSP frequency */
value = this->spec.freq;
if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SPEED, &value) < 0) {
perror("SNDCTL_DSP_SPEED");
DSP_CloseDevice(this);
return SDL_SetError("Couldn't set audio frequency");
}
this->spec.freq = value;
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(&this->spec);
/* Determine the power of two of the fragment size */
for (frag_spec = 0; (0x01U << frag_spec) < this->spec.size; ++frag_spec);
if ((0x01U << frag_spec) != this->spec.size) {
DSP_CloseDevice(this);
return SDL_SetError("Fragment size must be a power of two");
}
frag_spec |= 0x00020000; /* two fragments, for low latency */
/* Set the audio buffering parameters */
#ifdef DEBUG_AUDIO
fprintf(stderr, "Requesting %d fragments of size %d\n",
(frag_spec >> 16), 1 << (frag_spec & 0xFFFF));
#endif
if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0) {
perror("SNDCTL_DSP_SETFRAGMENT");
}
#ifdef DEBUG_AUDIO
{
audio_buf_info info;
ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETOSPACE, &info);
fprintf(stderr, "fragments = %d\n", info.fragments);
fprintf(stderr, "fragstotal = %d\n", info.fragstotal);
fprintf(stderr, "fragsize = %d\n", info.fragsize);
fprintf(stderr, "bytes = %d\n", info.bytes);
}
#endif
/* Allocate mixing buffer */
this->hidden->mixlen = this->spec.size;
this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
if (this->hidden->mixbuf == NULL) {
DSP_CloseDevice(this);
return SDL_OutOfMemory();
}
SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);
/* We're ready to rock and roll. :-) */
return 0;
}
static void
DSP_PlayDevice(_THIS)
{
const Uint8 *mixbuf = this->hidden->mixbuf;
const int mixlen = this->hidden->mixlen;
if (write(this->hidden->audio_fd, mixbuf, mixlen) == -1) {
perror("Audio write");
SDL_OpenedAudioDeviceDisconnected(this);
}
#ifdef DEBUG_AUDIO
fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen);
#endif
}
static Uint8 *
DSP_GetDeviceBuf(_THIS)
{
return (this->hidden->mixbuf);
}
static int
DSP_Init(SDL_AudioDriverImpl * impl)
{
/* Set the function pointers */
impl->DetectDevices = DSP_DetectDevices;
impl->OpenDevice = DSP_OpenDevice;
impl->PlayDevice = DSP_PlayDevice;
impl->GetDeviceBuf = DSP_GetDeviceBuf;
impl->CloseDevice = DSP_CloseDevice;
impl->AllowsArbitraryDeviceNames = 1;
return 1; /* this audio target is available. */
}
AudioBootStrap DSP_bootstrap = {
"dsp", "OSS /dev/dsp standard audio", DSP_Init, 0
};
#endif /* SDL_AUDIO_DRIVER_OSS */
/* vi: set ts=4 sw=4 expandtab: */
SDL_PrivateAudioData::mixlen
int mixlen
Definition: SDL_alsa_audio.h:40
OPEN_FLAGS_INPUT
#define OPEN_FLAGS_INPUT
Definition: SDL_audiodev_c.h:33
format
GLint GLint GLsizei GLsizei GLsizei GLint GLenum format
Definition: SDL_opengl.h:1565
SDL_FirstAudioFormat
SDL_AudioFormat SDL_FirstAudioFormat(SDL_AudioFormat format)
Definition: SDL_audio.c:1398
SDL_AudioDriverImpl::DetectDevices
void(* DetectDevices)(void)
Definition: SDL_sysaudio.h:71
AUDIO_U16LSB
#define AUDIO_U16LSB
Definition: SDL_audio.h:91
SDL_FreeAudioMem
#define SDL_FreeAudioMem
Definition: SDL_audiomem.h:24
SDL_AudioDriverImpl::PlayDevice
void(* PlayDevice)(_THIS)
Definition: SDL_sysaudio.h:75
SDL_OpenedAudioDeviceDisconnected
void SDL_OpenedAudioDeviceDisconnected(SDL_AudioDevice *device)
Definition: SDL_audio.c:364
SDL_AudioFormat
Uint16 SDL_AudioFormat
Audio format flags.
Definition: SDL_audio.h:64
SDL_PrivateAudioData
Definition: SDL_alsa_audio.h:33
SDL_NextAudioFormat
SDL_AudioFormat SDL_NextAudioFormat(void)
Definition: SDL_audio.c:1410
spec
SDL_AudioSpec spec
Definition: loopwave.c:35
SDL_GetAudioDeviceName
#define SDL_GetAudioDeviceName
Definition: SDL_dynapi_overrides.h:86
AUDIO_U8
#define AUDIO_U8
Definition: SDL_audio.h:89
SDL_EnumUnixAudioDevices
void SDL_EnumUnixAudioDevices(const int classic, int(*test)(int))
AudioBootStrap
Definition: SDL_sysaudio.h:189
SDL_AudioSpec::freq
int freq
Definition: SDL_audio.h:170
SDL_AudioSpec::channels
Uint8 channels
Definition: SDL_audio.h:172
value
GLsizei const GLfloat * value
Definition: SDL_opengl_glext.h:698
OPEN_FLAGS_OUTPUT
#define OPEN_FLAGS_OUTPUT
Definition: SDL_audiodev_c.h:32
_THIS
#define _THIS
Definition: SDL_alsa_audio.h:31
Uint8
uint8_t Uint8
An unsigned 8-bit integer type.
Definition: SDL_stdinc.h:139
SDL_free
void SDL_free(void *mem)
SDL_AudioDriverImpl
Definition: SDL_sysaudio.h:69
SDL_CalculateAudioSpec
void SDL_CalculateAudioSpec(SDL_AudioSpec *spec)
Definition: SDL_audio.c:1419
SDL_AllocAudioMem
#define SDL_AllocAudioMem
Definition: SDL_audiomem.h:23
SDL_AudioSpec::size
Uint32 size
Definition: SDL_audio.h:176
SDL_AudioDriverImpl::OpenDevice
int(* OpenDevice)(_THIS, void *handle, const char *devname, int iscapture)
Definition: SDL_sysaudio.h:72
NULL
#define NULL
Definition: begin_code.h:143
SDL_OutOfMemory
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
DSP_bootstrap
AudioBootStrap DSP_bootstrap
SDL_SetError
#define SDL_SetError
Definition: SDL_dynapi_overrides.h:36
SDL_AudioDriverImpl::CloseDevice
void(* CloseDevice)(_THIS)
Definition: SDL_sysaudio.h:79
SDL_AudioDriverImpl::AllowsArbitraryDeviceNames
int AllowsArbitraryDeviceNames
Definition: SDL_sysaudio.h:94
AUDIO_S16MSB
#define AUDIO_S16MSB
Definition: SDL_audio.h:94
SDL_audio.h
SDL_dspaudio.h
SDL_AudioSpec::format
SDL_AudioFormat format
Definition: SDL_audio.h:171
AUDIO_S16LSB
#define AUDIO_S16LSB
Definition: SDL_audio.h:92
SDL_AudioDriverImpl::GetDeviceBuf
Uint8 *(* GetDeviceBuf)(_THIS)
Definition: SDL_sysaudio.h:77
flags
GLbitfield flags
Definition: SDL_opengl_glext.h:1480
SDL_malloc
#define SDL_malloc
Definition: SDL_dynapi_overrides.h:380
SDL_PrivateAudioData::mixbuf
Uint8 * mixbuf
Definition: SDL_alsa_audio.h:39
SDL_timer.h
AUDIO_S8
#define AUDIO_S8
Definition: SDL_audio.h:90
SDL_memset
#define SDL_memset
Definition: SDL_dynapi_overrides.h:392
AUDIO_U16MSB
#define AUDIO_U16MSB
Definition: SDL_audio.h:93