/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

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

Lesser General Public License for more details.

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

Sam Lantinga

slouken@libsdl.org

*/

/* Allow access to an ESD network stream mixing buffer */

#include <errno.h>

#include <esd.h>

#include "SDL_timer.h"

#include "SDL_audio.h"

#include "../SDL_audiomem.h"

#include "../SDL_audio_c.h"

#include "../SDL_audiodev_c.h"

#include "SDL_esdaudio.h"

#ifdef SDL_AUDIO_DRIVER_ESD_DYNAMIC

#include "SDL_name.h"

#include "SDL_loadso.h"

#else

#define SDL_NAME(X) X

#endif

/* 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);

#ifdef SDL_AUDIO_DRIVER_ESD_DYNAMIC

static const char *esd_library = SDL_AUDIO_DRIVER_ESD_DYNAMIC;

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_arraysize(esd_functions); ++i ) {

*esd_functions[i].func = SDL_LoadFunction(esd_handle, esd_functions[i].name);

if ( !*esd_functions[i].func ) {

retval = -1;

UnloadESDLibrary();

break;

}

}

}

return retval;

}

#else

static void UnloadESDLibrary()

{

return;

}

static int LoadESDLibrary(void)

{

return 0;

}

#endif /* SDL_AUDIO_DRIVER_ESD_DYNAMIC */

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

int connection;

int available;

available = 0;

if ( LoadESDLibrary() < 0 ) {

return available;

}

connection = SDL_NAME(esd_open_sound)(NULL);

if ( connection >= 0 ) {

available = 1;

SDL_NAME(esd_close)(connection);

}

UnloadESDLibrary();

return(available);

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

SDL_free(device->hidden);

SDL_free(device);

UnloadESDLibrary();

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

SDL_AudioDevice *this;

/* Initialize all variables that we clean on shutdown */

LoadESDLibrary();

this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));

if ( this ) {

SDL_memset(this, 0, (sizeof *this));

this->hidden = (struct SDL_PrivateAudioData *)

SDL_malloc((sizeof *this->hidden));

}

if ( (this == NULL) || (this->hidden == NULL) ) {

SDL_OutOfMemory();

if ( this ) {

SDL_free(this);

}

return(0);

}

SDL_memset(this->hidden, 0, (sizeof *this->hidden));

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 ) {

SDL_NAME(esd_close)(audio_fd);

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];

SDL_snprintf(temp, SDL_arraysize(temp), "/proc/%d/cmdline", getpid());

fp = fopen(temp, "r");

if ( fp != NULL ) {

if ( fgets(temp, sizeof(temp)-1, fp) ) {

progname = SDL_strrchr(temp, '/');

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 */

audio_fd = SDL_NAME(esd_play_stream)(format, spec->freq, NULL, get_progname());

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);

}

SDL_memset(mixbuf, spec->silence, spec->size);

/* Get the parent process id (we're the parent of the audio thread) */

parent = getpid();

/* We're ready to rock and roll. :-) */

return(0);

}