/**

 *  $Id: audioplayer.c 53 2008-01-10 00:19:41Z mbroeker $

 * $URL: http://localhost/svn/c/VirtualReader/trunk/player/audioplayer.c $

 */

#include <audioplayer.h>

typedef struct {

    SDL_AudioSpec spec;         // internal structure

    Uint8 *sound_buffer;        // malloced pointer from sdl

    Uint32 sound_pos;           // position

    Uint32 sound_len;           // length in bytes

    Uint32 length;              // Length in Milliseconds

    int opened;                 // bool opened

    int loaded;                 // bool loaded

    int verbose;                // verbose messages

    int timeout;                // timeout

    int timer;                  // bool timer

} AudioDevice;

AudioDevice AD;

int audio_init ()

{

    // initialize SDL for audio output

    if (SDL_Init (SDL_INIT_AUDIO) < 0) {

        fprintf (stderr, "audio_init: Cannot initialize SDL-Subsystem\n");

        return -1;

    }

    AD.sound_buffer = 0;

    AD.sound_pos = 0;

    AD.sound_len = 0;

    AD.opened = 0;

    AD.loaded = 0;

    AD.verbose = 0;

    AD.timeout = 0;

    AD.timer = 0;

    return 0;

}

void audio_shutdown ()

{

    // quit sdl

    SDL_AudioQuit ();

    SDL_Quit ();

}

static void Callback (void *userdata, Uint8 * stream, int len)

{

    Uint8 *waveptr = NULL;

    /*

     *     loaded = 0 Segmentation fault

     *        len = 0 nothing to play

     */

    if (!(AD.loaded && len))

        return;

    waveptr = AD.sound_buffer + AD.sound_pos;

    SDL_MixAudio (stream, waveptr, len, SDL_MIX_MAXVOLUME);

    AD.sound_pos += len;        // bereits gespielt

    if (audioplayer_gettime () > (AD.length - AD.timeout)) {

        AD.sound_pos = AD.length;

        AD.sound_len = 0;

        AD.timer = 0;

    }

}

Uint32 audioplayer_getsoundlen ()

{

    return AD.sound_len;

}

void audioplayer_media_info (char *fname)

{

    AD.length = audioplayer_getwavelength (fname);

    printf ("Playing %s: %d Hz, %d Bit Audio, %d Channel(s), %3.2d ms\n",

            fname, AD.spec.freq, audioplayer_getbitrate (), AD.spec.channels, AD.length);

}

int audioplayer_getbitrate ()

{

    int bitrate = 0;

    switch (AD.spec.format) {

    case AUDIO_U8:

    case AUDIO_S8:

        bitrate = 8;

        break;

    case AUDIO_S16LSB:

    case AUDIO_S16MSB:

    case AUDIO_U16LSB:

    case AUDIO_U16MSB:

        bitrate = 16;

        break;

    }

    return bitrate;

}

Uint32 audioplayer_getwavelength (char *fname)

{

    struct stat info;

    Uint32 value = 0;

    if (fname == NULL)

        return AD.length;

    if (stat (fname, &info) == 0)

        /*

         * the value is really big, so be carefull

         * changes in the order result in different values

         * the storage type isn`t well choosen...

         */

        value = ((info.st_size) / (AD.spec.freq * AD.spec.channels * (audioplayer_getbitrate () / 8.0)) * 1000.0);

    return (value);

}

Uint32 audioplayer_getposition ()

{

    return AD.sound_pos;

}

Uint32 audioplayer_gettime ()

{

    Uint32 ret;

    ret = AD.sound_pos / (AD.spec.freq * AD.spec.channels * (audioplayer_getbitrate () / 8.0)) * 1000.0;

    return ret;

}

void audioplayer_settime (long tm)

{

    AD.sound_pos = tm / 1000.0 * (AD.spec.freq * AD.spec.channels * (audioplayer_getbitrate () / 8.0));

    /*

     * Eine Adresse ...

     */

    while ((AD.sound_pos % 2) != 0)

        AD.sound_pos++;

    if (AD.verbose)

        printf ("\e[31m[ATTENTION]\e[37m [#%d/#%d] = %d ms\n", AD.sound_pos, AD.sound_len, audioplayer_gettime ());

}

void audioplayer_stop ()

{

    /*

     * stops the callback function

     */

    SDL_PauseAudio (1);

    AD.spec.callback = NULL;

    if (AD.loaded == 1)

        SDL_FreeWAV (AD.sound_buffer);

    AD.loaded = 0;

    AD.timer = 0;

}

void audioplayer_delay (Uint32 milliseconds)

{

    struct timespec tm;

    tm.tv_sec = 0;

    tm.tv_nsec = milliseconds * 1000;

    while (AD.timer)

        nanosleep (&tm, NULL);

}

void audioplayer_setverbose (int verbose)

{

    AD.verbose = verbose;

}

int audioplayer (char *fname, Uint32 timeout)

{

    if (SDL_LoadWAV (fname, &AD.spec, &AD.sound_buffer, &AD.sound_len) == NULL) {

        printf ("SDL: %s\n", SDL_GetError ());

        return -1;

    }

    AD.loaded = 1;

    if (!AD.opened) {

        AD.spec.callback = Callback;

        if (SDL_OpenAudio (&AD.spec, NULL) < 0) {

            fprintf (stderr, "Cannot open audio device: %s\n", SDL_GetError ());

            return -1;

        }

        AD.opened = 1;

    }

    /*

     * calls implicitly getwavelength

     */

    audioplayer_media_info (fname);

    AD.sound_pos = 0;

    /*

     * starts playback via Callback function

     */

    SDL_PauseAudio (0);

    /*

     * initializes the timeout mechanism

     */

    AD.timer = 1;

    AD.timeout = timeout;

    /*

     * controlled delay

     */

    audioplayer_delay (timeout);

    return 0;

}