SDL_audio.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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/* Allow access to a raw mixing buffer */
#include "SDL.h"
#include "SDL_audio_c.h"
#include "SDL_audiomem.h"
#include "SDL_sysaudio.h"
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#ifdef __OS2__
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/* We'll need the DosSetPriority() API! */
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#define INCL_DOSPROCESS
#include <os2.h>
#endif
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/* Available audio drivers */
static AudioBootStrap *bootstrap[] = {
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#if SDL_AUDIO_DRIVER_BSD
&BSD_AUDIO_bootstrap,
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#if SDL_AUDIO_DRIVER_OSS
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&DSP_bootstrap,
&DMA_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_ALSA
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&ALSA_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_PULSE
&PULSE_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_QNXNTO
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&QNXNTOAUDIO_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_SUNAUDIO
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&SUNAUDIO_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_DMEDIA
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&DMEDIA_bootstrap,
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#if SDL_AUDIO_DRIVER_ARTS
&ARTS_bootstrap,
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#endif
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#if SDL_AUDIO_DRIVER_ESD
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&ESD_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_NAS
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&NAS_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_DSOUND
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&DSOUND_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_WAVEOUT
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&WAVEOUT_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_PAUD
&Paud_bootstrap,
#endif
#if SDL_AUDIO_DRIVER_BAUDIO
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&BAUDIO_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_COREAUDIO
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&COREAUDIO_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_SNDMGR
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&SNDMGR_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_MINT
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&MINTAUDIO_GSXB_bootstrap,
&MINTAUDIO_MCSN_bootstrap,
&MINTAUDIO_STFA_bootstrap,
&MINTAUDIO_XBIOS_bootstrap,
&MINTAUDIO_DMA8_bootstrap,
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#if SDL_AUDIO_DRIVER_DISK
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&DISKAUD_bootstrap,
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#if SDL_AUDIO_DRIVER_DUMMY
&DUMMYAUD_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_DC
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&DCAUD_bootstrap,
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#if SDL_AUDIO_DRIVER_NDS
&NDSAUD_bootstrap,
#endif
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#if SDL_AUDIO_DRIVER_MMEAUDIO
&MMEAUDIO_bootstrap,
#endif
#if SDL_AUDIO_DRIVER_DART
&DART_bootstrap,
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#endif
#if SDL_AUDIO_DRIVER_EPOCAUDIO
&EPOCAudio_bootstrap,
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NULL
};
SDL_AudioDevice *current_audio = NULL;
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/*
* If non-zero, use legacy behaviour (memset the callback buffer before call).
* Changed to NOT initializing the buffer before the callback in 1.2.12.
* Set environment SDL_AUDIO_MUST_INIT_BUFFERS=1 to get old behaviour.
*/
static int must_init_callback_buffer = 0;
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/* Various local functions */
int SDL_AudioInit(const char *driver_name);
void SDL_AudioQuit(void);
/* The general mixing thread function */
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{
SDL_AudioDevice *audio = (SDL_AudioDevice *)audiop;
Uint8 *stream;
int stream_len;
void *udata;
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int silence;
/* Perform any thread setup */
if ( audio->ThreadInit ) {
audio->ThreadInit(audio);
}
audio->threadid = SDL_ThreadID();
/* Set up the mixing function */
fill = audio->spec.callback;
udata = audio->spec.userdata;
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if ( audio->convert.needed ) {
if ( audio->convert.src_format == AUDIO_U8 ) {
silence = 0x80;
} else {
silence = 0;
}
stream_len = audio->convert.len;
} else {
silence = audio->spec.silence;
stream_len = audio->spec.size;
}
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#ifdef __OS2__
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/* Increase the priority of this thread to make sure that
the audio will be continuous all the time! */
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#ifdef USE_DOSSETPRIORITY
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if (SDL_getenv("SDL_USE_TIMECRITICAL_AUDIO"))
{
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#ifdef DEBUG_BUILD
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printf("[SDL_RunAudio] : Setting priority to TimeCritical+0! (TID%d)\n", SDL_ThreadID());
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#endif
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DosSetPriority(PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0);
}
else
{
#ifdef DEBUG_BUILD
printf("[SDL_RunAudio] : Setting priority to ForegroundServer+0! (TID%d)\n", SDL_ThreadID());
#endif
DosSetPriority(PRTYS_THREAD, PRTYC_FOREGROUNDSERVER, 0, 0);
}
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#endif
#endif
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/* Loop, filling the audio buffers */
while ( audio->enabled ) {
/* Fill the current buffer with sound */
if ( audio->convert.needed ) {
if ( audio->convert.buf ) {
stream = audio->convert.buf;
} else {
continue;
}
} else {
stream = audio->GetAudioBuf(audio);
if ( stream == NULL ) {
stream = audio->fake_stream;
}
}
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if ( must_init_callback_buffer ) {
SDL_memset(stream, silence, stream_len);
}
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if ( ! audio->paused ) {
SDL_mutexP(audio->mixer_lock);
(*fill)(udata, stream, stream_len);
SDL_mutexV(audio->mixer_lock);
}
/* Convert the audio if necessary */
if ( audio->convert.needed ) {
SDL_ConvertAudio(&audio->convert);
stream = audio->GetAudioBuf(audio);
if ( stream == NULL ) {
stream = audio->fake_stream;
}
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SDL_memcpy(stream, audio->convert.buf,
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audio->convert.len_cvt);
}
/* Ready current buffer for play and change current buffer */
if ( stream != audio->fake_stream ) {
audio->PlayAudio(audio);
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}
/* Wait for an audio buffer to become available */
if ( stream == audio->fake_stream ) {
SDL_Delay((audio->spec.samples*1000)/audio->spec.freq);
} else {
audio->WaitAudio(audio);
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}
}
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/* Wait for the audio to drain.. */
if ( audio->WaitDone ) {
audio->WaitDone(audio);
}
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#ifdef __OS2__
#ifdef DEBUG_BUILD
printf("[SDL_RunAudio] : Task exiting. (TID%d)\n", SDL_ThreadID());
#endif
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return(0);
}
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static void SDL_LockAudio_Default(SDL_AudioDevice *audio)
{
if ( audio->thread && (SDL_ThreadID() == audio->threadid) ) {
return;
}
SDL_mutexP(audio->mixer_lock);
}
static void SDL_UnlockAudio_Default(SDL_AudioDevice *audio)
{
if ( audio->thread && (SDL_ThreadID() == audio->threadid) ) {
return;
}
SDL_mutexV(audio->mixer_lock);
}
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static Uint16 SDL_ParseAudioFormat(const char *string)
{
Uint16 format = 0;
switch (*string) {
case 'U':
++string;
format |= 0x0000;
break;
case 'S':
++string;
format |= 0x8000;
break;
default:
return 0;
}
switch (SDL_atoi(string)) {
case 8:
string += 1;
format |= 8;
break;
case 16:
string += 2;
format |= 16;
if ( SDL_strcmp(string, "LSB") == 0
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
|| SDL_strcmp(string, "SYS") == 0
#endif
) {
format |= 0x0000;
}
if ( SDL_strcmp(string, "MSB") == 0
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
|| SDL_strcmp(string, "SYS") == 0
#endif
) {
format |= 0x1000;
}
break;
default:
return 0;
}
return format;
}
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int SDL_AudioInit(const char *driver_name)
{
SDL_AudioDevice *audio;
int i = 0, idx;
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const char *envr = SDL_getenv("SDL_AUDIO_MUST_INIT_BUFFERS");
must_init_callback_buffer = ((envr != NULL) && (SDL_atoi(envr)));
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/* Check to make sure we don't overwrite 'current_audio' */
if ( current_audio != NULL ) {
SDL_AudioQuit();
}
/* Select the proper audio driver */
audio = NULL;
idx = 0;
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#if SDL_AUDIO_DRIVER_ESD
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if ( (driver_name == NULL) && (SDL_getenv("ESPEAKER") != NULL) ) {
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/* Ahem, we know that if ESPEAKER is set, user probably wants
to use ESD, but don't start it if it's not already running.
This probably isn't the place to do this, but... Shh! :)
*/
for ( i=0; bootstrap[i]; ++i ) {
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if ( SDL_strcasecmp(bootstrap[i]->name, "esd") == 0 ) {
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#ifdef HAVE_PUTENV
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const char *esd_no_spawn;
/* Don't start ESD if it's not running */
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esd_no_spawn = getenv("ESD_NO_SPAWN");
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if ( esd_no_spawn == NULL ) {
putenv("ESD_NO_SPAWN=1");
}
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if ( bootstrap[i]->available() ) {
audio = bootstrap[i]->create(0);
break;
}
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#ifdef HAVE_UNSETENV
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if ( esd_no_spawn == NULL ) {
unsetenv("ESD_NO_SPAWN");
}
#endif
}
}
}
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#endif /* SDL_AUDIO_DRIVER_ESD */
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if ( audio == NULL ) {
if ( driver_name != NULL ) {
#if 0 /* This will be replaced with a better driver selection API */
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if ( SDL_strrchr(driver_name, ':') != NULL ) {
idx = atoi(SDL_strrchr(driver_name, ':')+1);
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}
#endif
for ( i=0; bootstrap[i]; ++i ) {
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if (SDL_strcasecmp(bootstrap[i]->name, driver_name) == 0) {
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if ( bootstrap[i]->available() ) {
audio=bootstrap[i]->create(idx);
break;
}
}
}
} else {
for ( i=0; bootstrap[i]; ++i ) {
if ( bootstrap[i]->available() ) {
audio = bootstrap[i]->create(idx);
if ( audio != NULL ) {
break;
}
}
}
}
if ( audio == NULL ) {
SDL_SetError("No available audio device");
#if 0 /* Don't fail SDL_Init() if audio isn't available.
SDL_OpenAudio() will handle it at that point. *sigh*
*/
return(-1);
#endif
}
}
current_audio = audio;
if ( current_audio ) {
current_audio->name = bootstrap[i]->name;
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if ( !current_audio->LockAudio && !current_audio->UnlockAudio ) {
current_audio->LockAudio = SDL_LockAudio_Default;
current_audio->UnlockAudio = SDL_UnlockAudio_Default;
}
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}
return(0);
}
char *SDL_AudioDriverName(char *namebuf, int maxlen)
{
if ( current_audio != NULL ) {
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SDL_strlcpy(namebuf, current_audio->name, maxlen);
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return(namebuf);
}
return(NULL);
}
int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained)
{
SDL_AudioDevice *audio;
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/* Start up the audio driver, if necessary */
if ( ! current_audio ) {
if ( (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) ||
(current_audio == NULL) ) {
return(-1);
}
}
audio = current_audio;
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if (audio->opened) {
SDL_SetError("Audio device is already opened");
return(-1);
}
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/* Verify some parameters */
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if ( desired->freq == 0 ) {
env = SDL_getenv("SDL_AUDIO_FREQUENCY");
if ( env ) {
desired->freq = SDL_atoi(env);
}
}
if ( desired->freq == 0 ) {
/* Pick some default audio frequency */
desired->freq = 22050;
}
if ( desired->format == 0 ) {
env = SDL_getenv("SDL_AUDIO_FORMAT");
if ( env ) {
desired->format = SDL_ParseAudioFormat(env);
}
}
if ( desired->format == 0 ) {
/* Pick some default audio format */
desired->format = AUDIO_S16;
}
if ( desired->channels == 0 ) {
env = SDL_getenv("SDL_AUDIO_CHANNELS");
if ( env ) {
desired->channels = SDL_atoi(env);
}
}
if ( desired->channels == 0 ) {
/* Pick a default number of channels */
desired->channels = 2;
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}
switch ( desired->channels ) {
case 1: /* Mono */
case 2: /* Stereo */
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case 4: /* surround */
case 6: /* surround with center and lfe */
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break;
default:
SDL_SetError("1 (mono) and 2 (stereo) channels supported");
return(-1);
}
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if ( desired->samples == 0 ) {
env = SDL_getenv("SDL_AUDIO_SAMPLES");
if ( env ) {
desired->samples = SDL_atoi(env);
}
}
if ( desired->samples == 0 ) {
/* Pick a default of ~46 ms at desired frequency */
int samples = (desired->freq / 1000) * 46;
int power2 = 1;
while ( power2 < samples ) {
power2 *= 2;
}
desired->samples = power2;
}
if ( desired->callback == NULL ) {
SDL_SetError("SDL_OpenAudio() passed a NULL callback");
return(-1);
}
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#if SDL_THREADS_DISABLED
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/* Uses interrupt driven audio, without thread */
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#else
/* Create a semaphore for locking the sound buffers */
audio->mixer_lock = SDL_CreateMutex();
if ( audio->mixer_lock == NULL ) {
SDL_SetError("Couldn't create mixer lock");
SDL_CloseAudio();
return(-1);
}
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#endif /* SDL_THREADS_DISABLED */
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/* Calculate the silence and size of the audio specification */
SDL_CalculateAudioSpec(desired);
/* Open the audio subsystem */
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SDL_memcpy(&audio->spec, desired, sizeof(audio->spec));
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audio->convert.needed = 0;
audio->enabled = 1;
audio->paused = 1;
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audio->opened = audio->OpenAudio(audio, &audio->spec)+1;
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if ( ! audio->opened ) {
SDL_CloseAudio();
return(-1);
}
/* If the audio driver changes the buffer size, accept it */
if ( audio->spec.samples != desired->samples ) {
desired->samples = audio->spec.samples;
SDL_CalculateAudioSpec(desired);
}
/* Allocate a fake audio memory buffer */
audio->fake_stream = SDL_AllocAudioMem(audio->spec.size);
if ( audio->fake_stream == NULL ) {
SDL_CloseAudio();
SDL_OutOfMemory();
return(-1);
}
/* See if we need to do any conversion */
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if ( obtained != NULL ) {
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SDL_memcpy(obtained, &audio->spec, sizeof(audio->spec));
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} else if ( desired->freq != audio->spec.freq ||
desired->format != audio->spec.format ||
desired->channels != audio->spec.channels ) {
/* Build an audio conversion block */
if ( SDL_BuildAudioCVT(&audio->convert,
desired->format, desired->channels,
desired->freq,
audio->spec.format, audio->spec.channels,
audio->spec.freq) < 0 ) {
SDL_CloseAudio();
return(-1);
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}
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if ( audio->convert.needed ) {
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audio->convert.len = (int) ( ((double) desired->size) /
audio->convert.len_ratio );
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audio->convert.buf =(Uint8 *)SDL_AllocAudioMem(
audio->convert.len*audio->convert.len_mult);
if ( audio->convert.buf == NULL ) {
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SDL_CloseAudio();
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SDL_OutOfMemory();
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return(-1);
}
}
}
/* Start the audio thread if necessary */
switch (audio->opened) {
case 1:
/* Start the audio thread */
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#if (defined(__WIN32__) && !defined(_WIN32_WCE)) && !defined(HAVE_LIBC) && !defined(__SYMBIAN32__)
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#undef SDL_CreateThread
audio->thread = SDL_CreateThread(SDL_RunAudio, audio, NULL, NULL);
#else
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audio->thread = SDL_CreateThread(SDL_RunAudio, audio);
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if ( audio->thread == NULL ) {
SDL_CloseAudio();
SDL_SetError("Couldn't create audio thread");
return(-1);
}
break;
default:
/* The audio is now playing */
break;
}
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return(0);
}
SDL_audiostatus SDL_GetAudioStatus(void)
{
SDL_AudioDevice *audio = current_audio;
SDL_audiostatus status;
status = SDL_AUDIO_STOPPED;
if ( audio && audio->enabled ) {
if ( audio->paused ) {
status = SDL_AUDIO_PAUSED;
} else {
status = SDL_AUDIO_PLAYING;
}
}
return(status);
}
void SDL_PauseAudio (int pause_on)
{
SDL_AudioDevice *audio = current_audio;
if ( audio ) {
audio->paused = pause_on;
}
}
void SDL_LockAudio (void)
{
SDL_AudioDevice *audio = current_audio;
/* Obtain a lock on the mixing buffers */
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if ( audio && audio->LockAudio ) {
audio->LockAudio(audio);
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}
}
void SDL_UnlockAudio (void)
{
SDL_AudioDevice *audio = current_audio;
/* Release lock on the mixing buffers */
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if ( audio && audio->UnlockAudio ) {
audio->UnlockAudio(audio);
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}
}
void SDL_CloseAudio (void)
{
SDL_QuitSubSystem(SDL_INIT_AUDIO);
}
void SDL_AudioQuit(void)
{
SDL_AudioDevice *audio = current_audio;
if ( audio ) {
audio->enabled = 0;
if ( audio->thread != NULL ) {
SDL_WaitThread(audio->thread, NULL);
}
if ( audio->mixer_lock != NULL ) {
SDL_DestroyMutex(audio->mixer_lock);
}
if ( audio->fake_stream != NULL ) {
SDL_FreeAudioMem(audio->fake_stream);
}
if ( audio->convert.needed ) {
SDL_FreeAudioMem(audio->convert.buf);
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}
if ( audio->opened ) {
audio->CloseAudio(audio);
audio->opened = 0;
}
/* Free the driver data */
audio->free(audio);
current_audio = NULL;
}
}
#define NUM_FORMATS 6
static int format_idx;
static int format_idx_sub;
static Uint16 format_list[NUM_FORMATS][NUM_FORMATS] = {
{ AUDIO_U8, AUDIO_S8, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB },
{ AUDIO_S8, AUDIO_U8, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB },
{ AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB, AUDIO_U8, AUDIO_S8 },
{ AUDIO_S16MSB, AUDIO_S16LSB, AUDIO_U16MSB, AUDIO_U16LSB, AUDIO_U8, AUDIO_S8 },
{ AUDIO_U16LSB, AUDIO_U16MSB, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U8, AUDIO_S8 },
{ AUDIO_U16MSB, AUDIO_U16LSB, AUDIO_S16MSB, AUDIO_S16LSB, AUDIO_U8, AUDIO_S8 },
};
Uint16 SDL_FirstAudioFormat(Uint16 format)
{
for ( format_idx=0; format_idx < NUM_FORMATS; ++format_idx ) {
if ( format_list[format_idx][0] == format ) {
break;
}
}
format_idx_sub = 0;
return(SDL_NextAudioFormat());
}
Uint16 SDL_NextAudioFormat(void)
{
if ( (format_idx == NUM_FORMATS) || (format_idx_sub == NUM_FORMATS) ) {
return(0);
}
return(format_list[format_idx][format_idx_sub++]);
}
void SDL_CalculateAudioSpec(SDL_AudioSpec *spec)
{
switch (spec->format) {
case AUDIO_U8:
spec->silence = 0x80;
break;
default:
spec->silence = 0x00;
break;
}
spec->size = (spec->format&0xFF)/8;
spec->size *= spec->channels;
spec->size *= spec->samples;
}