/*

    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

*/

#include "SDL_config.h"

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

#include <sys/types.h>

#include <unistd.h>

#include <signal.h>

#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);

}

/* vi: set ts=4 sw=4 expandtab: */