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SDL_esdaudio.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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*/
/* Allow access to an ESD network stream mixing buffer */
#ifdef ESD_SUPPORT
#include <errno.h>
#include <esd.h>
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#include "SDL_timer.h"
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#include "SDL_audio.h"
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#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "../SDL_audiodev_c.h"
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#include "SDL_esdaudio.h"
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#ifdef SDL_AUDIO_DRIVER_ESD_DYNAMIC
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#include "SDL_name.h"
#include "SDL_loadso.h"
#else
#define SDL_NAME(X) X
#endif
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/* The tag name used by ESD audio */
#define ESD_DRIVER_NAME "esd"
/* Audio driver functions */
static int ESD_OpenAudio(_THIS, SDL_AudioSpec *spec);
static void ESD_WaitAudio(_THIS);
static void ESD_PlayAudio(_THIS);
static Uint8 *ESD_GetAudioBuf(_THIS);
static void ESD_CloseAudio(_THIS);
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#ifdef SDL_AUDIO_DRIVER_ESD_DYNAMIC
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static const char *esd_library = SDL_AUDIO_DRIVER_ESD_DYNAMIC;
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static void *esd_handle = NULL;
static int esd_loaded = 0;
static int (*SDL_NAME(esd_open_sound))( const char *host );
static int (*SDL_NAME(esd_close))( int esd );
static int (*SDL_NAME(esd_play_stream))( esd_format_t format, int rate,
const char *host, const char *name );
static struct {
const char *name;
void **func;
} esd_functions[] = {
{ "esd_open_sound", (void **)&SDL_NAME(esd_open_sound) },
{ "esd_close", (void **)&SDL_NAME(esd_close) },
{ "esd_play_stream", (void **)&SDL_NAME(esd_play_stream) },
};
static void UnloadESDLibrary()
{
if ( esd_loaded ) {
SDL_UnloadObject(esd_handle);
esd_handle = NULL;
esd_loaded = 0;
}
}
static int LoadESDLibrary(void)
{
int i, retval = -1;
esd_handle = SDL_LoadObject(esd_library);
if ( esd_handle ) {
esd_loaded = 1;
retval = 0;
for ( i=0; i<SDL_TABLESIZE(esd_functions); ++i ) {
*esd_functions[i].func = SDL_LoadFunction(esd_handle, esd_functions[i].name);
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if ( !*esd_functions[i].func ) {
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retval = -1;
UnloadESDLibrary();
break;
}
}
}
return retval;
}
#else
static void UnloadESDLibrary()
{
return;
}
static int LoadESDLibrary(void)
{
return 0;
}
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#endif /* SDL_AUDIO_DRIVER_ESD_DYNAMIC */
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/* Audio driver bootstrap functions */
static int Audio_Available(void)
{
int connection;
int available;
available = 0;
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if ( LoadESDLibrary() < 0 ) {
return available;
}
connection = SDL_NAME(esd_open_sound)(NULL);
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if ( connection >= 0 ) {
available = 1;
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SDL_NAME(esd_close)(connection);
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}
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UnloadESDLibrary();
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return(available);
}
static void Audio_DeleteDevice(SDL_AudioDevice *device)
{
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SDL_free(device->hidden);
SDL_free(device);
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UnloadESDLibrary();
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}
static SDL_AudioDevice *Audio_CreateDevice(int devindex)
{
SDL_AudioDevice *this;
/* Initialize all variables that we clean on shutdown */
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LoadESDLibrary();
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this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
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if ( this ) {
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SDL_memset(this, 0, (sizeof *this));
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this->hidden = (struct SDL_PrivateAudioData *)
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SDL_malloc((sizeof *this->hidden));
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}
if ( (this == NULL) || (this->hidden == NULL) ) {
SDL_OutOfMemory();
if ( this ) {
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SDL_free(this);
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}
return(0);
}
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SDL_memset(this->hidden, 0, (sizeof *this->hidden));
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audio_fd = -1;
/* Set the function pointers */
this->OpenAudio = ESD_OpenAudio;
this->WaitAudio = ESD_WaitAudio;
this->PlayAudio = ESD_PlayAudio;
this->GetAudioBuf = ESD_GetAudioBuf;
this->CloseAudio = ESD_CloseAudio;
this->free = Audio_DeleteDevice;
return this;
}
AudioBootStrap ESD_bootstrap = {
ESD_DRIVER_NAME, "Enlightened Sound Daemon",
Audio_Available, Audio_CreateDevice
};
/* This function waits until it is possible to write a full sound buffer */
static void ESD_WaitAudio(_THIS)
{
Sint32 ticks;
/* Check to see if the thread-parent process is still alive */
{ static int cnt = 0;
/* Note that this only works with thread implementations
that use a different process id for each thread.
*/
if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
if ( kill(parent, 0) < 0 ) {
this->enabled = 0;
}
}
}
/* Use timer for general audio synchronization */
ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
if ( ticks > 0 ) {
SDL_Delay(ticks);
}
}
static void ESD_PlayAudio(_THIS)
{
int written;
/* Write the audio data, checking for EAGAIN on broken audio drivers */
do {
written = write(audio_fd, mixbuf, mixlen);
if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) {
SDL_Delay(1); /* Let a little CPU time go by */
}
} while ( (written < 0) &&
((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) );
/* Set the next write frame */
next_frame += frame_ticks;
/* If we couldn't write, assume fatal error for now */
if ( written < 0 ) {
this->enabled = 0;
}
}
static Uint8 *ESD_GetAudioBuf(_THIS)
{
return(mixbuf);
}
static void ESD_CloseAudio(_THIS)
{
if ( mixbuf != NULL ) {
SDL_FreeAudioMem(mixbuf);
mixbuf = NULL;
}
if ( audio_fd >= 0 ) {
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SDL_NAME(esd_close)(audio_fd);
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audio_fd = -1;
}
}
/* Try to get the name of the program */
static char *get_progname(void)
{
char *progname = NULL;
#ifdef linux
FILE *fp;
static char temp[BUFSIZ];
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SDL_snprintf(temp, SDL_arraysize(temp), "/proc/%d/cmdline", getpid());
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fp = fopen(temp, "r");
if ( fp != NULL ) {
if ( fgets(temp, sizeof(temp)-1, fp) ) {
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progname = SDL_strrchr(temp, '/');
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if ( progname == NULL ) {
progname = temp;
} else {
progname = progname+1;
}
}
fclose(fp);
}
#endif
return(progname);
}
static int ESD_OpenAudio(_THIS, SDL_AudioSpec *spec)
{
esd_format_t format;
/* Convert audio spec to the ESD audio format */
format = (ESD_STREAM | ESD_PLAY);
switch ( spec->format & 0xFF ) {
case 8:
format |= ESD_BITS8;
break;
case 16:
format |= ESD_BITS16;
break;
default:
SDL_SetError("Unsupported ESD audio format");
return(-1);
}
if ( spec->channels == 1 ) {
format |= ESD_MONO;
} else {
format |= ESD_STEREO;
}
#if 0
spec->samples = ESD_BUF_SIZE; /* Darn, no way to change this yet */
#endif
/* Open a connection to the ESD audio server */
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audio_fd = SDL_NAME(esd_play_stream)(format, spec->freq, NULL, get_progname());
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if ( audio_fd < 0 ) {
SDL_SetError("Couldn't open ESD connection");
return(-1);
}
/* Calculate the final parameters for this audio specification */
SDL_CalculateAudioSpec(spec);
frame_ticks = (float)(spec->samples*1000)/spec->freq;
next_frame = SDL_GetTicks()+frame_ticks;
/* Allocate mixing buffer */
mixlen = spec->size;
mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
if ( mixbuf == NULL ) {
return(-1);
}
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SDL_memset(mixbuf, spec->silence, spec->size);
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/* Get the parent process id (we're the parent of the audio thread) */
parent = getpid();
/* We're ready to rock and roll. :-) */
return(0);
}
#endif /* ESD_SUPPORT */