/*

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 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"

#ifdef ARTSC_DYNAMIC

#include "SDL_name.h"

#include "SDL_loadso.h"

#else

#define SDL_NAME(X) X

#endif

/* The tag name used by artsc audio */

#define ARTSC_DRIVER_NAME "arts"

/* 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);

#ifdef ARTSC_DYNAMIC

static const char *arts_library = ARTSC_DYNAMIC;

static void *arts_handle = NULL;

static int arts_loaded = 0;

static int (*SDL_NAME(arts_init))(void);

static void (*SDL_NAME(arts_free))(void);

static arts_stream_t (*SDL_NAME(arts_play_stream))(int rate, int bits, int channels, const char *name);

static int (*SDL_NAME(arts_stream_set))(arts_stream_t s, arts_parameter_t param, int value);

static int (*SDL_NAME(arts_stream_get))(arts_stream_t s, arts_parameter_t param);

static int (*SDL_NAME(arts_write))(arts_stream_t s, const void *buffer, int count);

static void (*SDL_NAME(arts_close_stream))(arts_stream_t s);

static struct {

const char *name;

void **func;

} arts_functions[] = {

{ "arts_init", (void **)&SDL_NAME(arts_init) },

{ "arts_free", (void **)&SDL_NAME(arts_free) },

{ "arts_play_stream", (void **)&SDL_NAME(arts_play_stream) },

{ "arts_stream_set", (void **)&SDL_NAME(arts_stream_set) },

{ "arts_stream_get", (void **)&SDL_NAME(arts_stream_get) },

{ "arts_write", (void **)&SDL_NAME(arts_write) },

{ "arts_close_stream", (void **)&SDL_NAME(arts_close_stream) },

};

static void UnloadARTSLibrary()

{

if ( arts_loaded ) {

SDL_UnloadObject(arts_handle);

arts_handle = NULL;

arts_loaded = 0;

}

}

static int LoadARTSLibrary(void)

{

int i, retval = -1;

arts_handle = SDL_LoadObject(arts_library);

if ( arts_handle ) {

arts_loaded = 1;

retval = 0;

for ( i=0; i<SDL_TABLESIZE(arts_functions); ++i ) {

*arts_functions[i].func = SDL_LoadFunction(arts_handle, arts_functions[i].name);

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

retval = -1;

UnloadARTSLibrary();

break;

}

}

}

return retval;

}

#else

static void UnloadARTSLibrary()

{

return;

}

static int LoadARTSLibrary(void)

{

return 0;

}

#endif /* ARTSC_DYNAMIC */

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

int available = 0;

if ( LoadARTSLibrary() < 0 ) {

return available;

}

if ( SDL_NAME(arts_init)() == 0 ) {

#define ARTS_CRASH_HACK /* Play a stream so aRts doesn't crash */

#ifdef ARTS_CRASH_HACK

arts_stream_t stream2;

stream2=SDL_NAME(arts_play_stream)(44100, 16, 2, "SDL");

SDL_NAME(arts_write)(stream2, "", 0);

SDL_NAME(arts_close_stream)(stream2);

#endif

available = 1;

SDL_NAME(arts_free)();

}

UnloadARTSLibrary();

return available;

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

free(device->hidden);

free(device);

UnloadARTSLibrary();

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

SDL_AudioDevice *this;

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

LoadARTSLibrary();

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 = SDL_NAME(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 ) {

SDL_NAME(arts_close_stream)(stream);

stream = 0;

}

SDL_NAME(arts_free)();

}

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;

if ( SDL_NAME(arts_init)() != 0 ) {

SDL_SetError("Unable to initialize ARTS");

return(-1);

}

stream = SDL_NAME(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

SDL_NAME(arts_stream_set)(stream, ARTS_P_PACKET_SETTINGS, frag_spec);

#else

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

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

#endif

spec->size = SDL_NAME(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);

}