/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga

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

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 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

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

*/

#ifdef SAVE_RCSID

static char rcsid =

"@(#) $Id$";

#endif

/* Allow access to a raw mixing buffer */

#include <sys/types.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <errno.h>

#include <signal.h>

#include <unistd.h>

#include "SDL_audio.h"

#include "SDL_error.h"

#include "SDL_audiomem.h"

#include "SDL_audio_c.h"

#include "SDL_timer.h"

#include "SDL_audiodev_c.h"

#include "SDL_artsaudio.h"

/* The tag name used by artsc audio */

#define ARTSC_DRIVER_NAME "artsc"

/* Audio driver functions */

static int ARTSC_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void ARTSC_WaitAudio(_THIS);

static void ARTSC_PlayAudio(_THIS);

static Uint8 *ARTSC_GetAudioBuf(_THIS);

static void ARTSC_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

if(arts_init())

return 0;

else

return 1;

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

free(device->hidden);

free(device);

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

SDL_AudioDevice *this;

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

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

if ( this ) {

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

this->hidden = (struct SDL_PrivateAudioData *)

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

}

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

SDL_OutOfMemory();

if ( this ) {

free(this);

}

return(0);

}

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

stream = 0;

/* Set the function pointers */

this->OpenAudio = ARTSC_OpenAudio;

this->WaitAudio = ARTSC_WaitAudio;

this->PlayAudio = ARTSC_PlayAudio;

this->GetAudioBuf = ARTSC_GetAudioBuf;

this->CloseAudio = ARTSC_CloseAudio;

this->free = Audio_DeleteDevice;

return this;

}

AudioBootStrap ARTSC_bootstrap = {

ARTSC_DRIVER_NAME, "Analog Realtime Synthesizer",

Audio_Available, Audio_CreateDevice

};

/* This function waits until it is possible to write a full sound buffer */

static void ARTSC_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 ARTSC_PlayAudio(_THIS)

{

int written;

/* Write the audio data */

written = arts_write(stream, mixbuf, mixlen);

/* If timer synchronization is enabled, set the next write frame */

if ( frame_ticks ) {

next_frame += frame_ticks;

}

/* If we couldn't write, assume fatal error for now */

if ( written < 0 ) {

this->enabled = 0;

}

#ifdef DEBUG_AUDIO

fprintf(stderr, "Wrote %d bytes of audio data\n", written);

#endif

}

static Uint8 *ARTSC_GetAudioBuf(_THIS)

{

return(mixbuf);

}

static void ARTSC_CloseAudio(_THIS)

{

if ( mixbuf != NULL ) {

SDL_FreeAudioMem(mixbuf);

mixbuf = NULL;

}

if ( stream ) {

arts_close_stream(stream);

stream = 0;

}

}

static int ARTSC_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

int bits, frag_spec;

Uint16 test_format, format;

/* Reset the timer synchronization flag */

frame_ticks = 0.0;

mixbuf = NULL;

/* Try for a closest match on audio format */

format = 0;

bits = 0;

for ( test_format = SDL_FirstAudioFormat(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:

bits = 8;

format = 1;

break;

case AUDIO_S16LSB:

bits = 16;

format = 1;

break;

default:

format = 0;

break;

}

if ( ! format ) {

test_format = SDL_NextAudioFormat();

}

}

if ( format == 0 ) {

SDL_SetError("Couldn't find any hardware audio formats");

return(-1);

}

spec->format = test_format;

stream = arts_play_stream(spec->freq, bits, spec->channels, "SDL");

/* Calculate the final parameters for this audio specification */

SDL_CalculateAudioSpec(spec);

/* Determine the power of two of the fragment size */

for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );

if ( (0x01<<frag_spec) != spec->size ) {

SDL_SetError("Fragment size must be a power of two");

return(-1);

}

frag_spec |= 0x00020000; /* two fragments, for low latency */

#ifdef ARTS_P_PACKET_SETTINGS

arts_stream_set(stream, ARTS_P_PACKET_SETTINGS, frag_spec);

#else

arts_stream_set(stream, ARTS_P_PACKET_SIZE, frag_spec&0xffff);

arts_stream_set(stream, ARTS_P_PACKET_COUNT, frag_spec>>16);

#endif

spec->size = arts_stream_get(stream, ARTS_P_PACKET_SIZE);

/* Allocate mixing buffer */

mixlen = spec->size;

mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);

if ( mixbuf == NULL ) {

return(-1);

}

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);

}