/*
 * SDL_sound -- An abstract sound format decoding API.
 * Copyright (C) 2001  Ryan C. Gordon.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * Ogg Vorbis decoder for SDL_sound.
 *
 * This driver handles .OGG audio files, and depends on libvorbisfile to
 *  do the actual decoding work. libvorbisfile is part of libvorbis, which
 *  is part of the Ogg Vorbis project.
 *
 *   Ogg Vorbis: http://www.xiph.org/ogg/vorbis/
 *   vorbisfile documentation: http://www.xiph.org/ogg/vorbis/doc/vorbisfile/
 *
 * Please see the file LICENSE in the source's root directory.
 *
 *  This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <assert.h>
#include "vorbis/codec.h"
#include "vorbis/vorbisfile.h"

#include "SDL_sound.h"

#define __SDL_SOUND_INTERNAL__
#include "SDL_sound_internal.h"

#if (!defined SOUND_SUPPORTS_OGG)
#error SOUND_SUPPORTS_OGG must be defined.
#endif


static int OGG_open(Sound_Sample *sample, const char *ext);
static void OGG_close(Sound_Sample *sample);
static Uint32 OGG_read(Sound_Sample *sample);

const Sound_DecoderFunctions __Sound_DecoderFunctions_OGG =
{
    {
        "OGG",
        "Ogg Vorbis audio through VorbisFile",
        "Ryan C. Gordon <icculus@clutteredmind.org>",
        "http://www.icculus.org/SDL_sound/"
    },

    OGG_open,       /* open() method       */
    OGG_close,      /* close() method       */
    OGG_read        /* read() method       */
};


    /*
     * These are callbacks from vorbisfile that let them read data from
     *  a RWops...
     */

size_t RWops_ogg_read(void *ptr, size_t size, size_t nmemb, void *datasource)
{
    return((size_t) SDL_RWread((SDL_RWops *) datasource, ptr, size, nmemb));
} /* RWops_ogg_read */

int RWops_ogg_seek(void *datasource, int64_t offset, int whence)
{
    return(SDL_RWseek((SDL_RWops *) datasource, offset, whence));
} /* RWops_ogg_seek */

int RWops_ogg_close(void *datasource)
{
    /* do nothing; SDL_sound will delete the RWops at a higher level. */
    return(0);  /* this is success in fclose(), so I guess that's okay. */
} /* RWops_ogg_close */

long RWops_ogg_tell(void *datasource)
{
    return((long) SDL_RWtell((SDL_RWops *) datasource));
} /* RWops_ogg_tell */

static const ov_callbacks RWops_ogg_callbacks =
{
    RWops_ogg_read,
    RWops_ogg_seek,
    RWops_ogg_close,
    RWops_ogg_tell
};


    /* Return a human readable version of an VorbisFile error code... */
static const char *ogg_error(int errnum)
{
    switch(errnum)
    {
        case OV_EREAD:
            return("i/o error");
        case OV_ENOTVORBIS:
            return("not a vorbis file");
        case OV_EVERSION:
            return("Vorbis version mismatch");
        case OV_EBADHEADER:
            return("invalid Vorbis bitstream header");
        case OV_EFAULT:
            return("internal logic fault in Vorbis library");
    } /* switch */

    return("unknown error");
} /* ogg_error */


static __inline__ void output_ogg_comments(OggVorbis_File *vf)
{
#if (defined DEBUG_CHATTER)
    int i;
    vorbis_comment *vc = ov_comment(vf, -1);

    if (vc == NULL)
        return;

    _D(("OGG: vendor == [%s].\n", vc->vendor));
    for (i = 0; i < vc->comments; i++)
    {
        _D(("OGG: user comment [%s].\n", vc->user_comments[i]));
    } /* for */
#endif
} /* output_ogg_comments */


static int OGG_open(Sound_Sample *sample, const char *ext)
{
    int rc;
    OggVorbis_File *vf;
    vorbis_info *info;
    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;

    vf = (OggVorbis_File *) malloc(sizeof (OggVorbis_File));
    BAIL_IF_MACRO(vf == NULL, ERR_OUT_OF_MEMORY, 0);

    rc = ov_open_callbacks(internal->rw, vf, NULL, 0, RWops_ogg_callbacks);
    if (rc != 0)
    {
        _D(("OGG: can't grok data. reason: [%s].\n", ogg_error(rc)));
        free(vf);
        BAIL_MACRO("OGG: Not valid Ogg Vorbis data.", 0);
    } /* if */

    info = ov_info(vf, -1);
    if (info == NULL)
    {
        ov_clear(vf);
        free(vf);
        BAIL_MACRO("OGG: failed to retrieve bitstream info", 0);
    } /* if */

    _D(("OGG: Accepting data stream.\n"));

    output_ogg_comments(vf);
    _D(("OGG: bitstream version == (%d).\n", info->version));
    _D(("OGG: bitstream channels == (%d).\n", info->channels));
    _D(("OGG: bitstream sampling rate == (%ld).\n", info->rate));
    _D(("OGG: seekable == {%s}.\n", ov_seekable(vf) ? "TRUE" : "FALSE"));
    _D(("OGG: number of logical bitstreams == (%ld).\n", ov_streams(vf)));
    _D(("OGG: serial number == (%ld).\n", ov_serialnumber(vf, -1)));
    _D(("OGG: total seconds of sample == (%f).\n", ov_time_total(vf, -1)));

    internal->decoder_private = vf;
    sample->flags = SOUND_SAMPLEFLAG_NONE;
    sample->actual.rate = (Uint32) info->rate;
    sample->actual.channels = (Uint8) info->channels;

    /*
     * Since we might have more than one logical bitstream in the OGG file,
     *  and these bitstreams may be in different formats, we might be
     *  converting two or three times: once in vorbisfile, once again in
     *  SDL_sound, and perhaps a third time to get it to the sound device's
     *  format. That's wickedly inefficient.
     *
     * To combat this a little, if the user specified a desired format, we
     *  claim that to be the "actual" format of the collection of logical
     *  bitstreams. This means that VorbisFile will do a conversion as
     *  necessary, and SDL_sound will not. If the user didn't specify a
     *  desired format, then we pretend the "actual" format is something that
     *  OGG files are apparently commonly encoded in.
     */
    sample->actual.format = (sample->desired.format == 0) ?
                             AUDIO_S16LSB : sample->desired.format;
    return(1);
} /* OGG_open */


static void OGG_close(Sound_Sample *sample)
{
    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
    ov_clear(vf);
    free(vf);
} /* OGG_close */


static Uint32 OGG_read(Sound_Sample *sample)
{
    int rc;
    int bitstream;
    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;

    rc = ov_read(vf, internal->buffer, internal->buffer_size,
            ((sample->actual.format & 0x1000) ? 1 : 0), /* bigendian? */
            ((sample->actual.format & 0xFF) / 8), /* bytes per sample point */
            ((sample->actual.format & 0x8000) ? 1 : 0), /* signed data? */
            &bitstream);

        /* Make sure the read went smoothly... */
    if (rc == 0)
        sample->flags |= SOUND_SAMPLEFLAG_EOF;

    else if (rc < 0)
        sample->flags |= SOUND_SAMPLEFLAG_ERROR;

        /* (next call this EAGAIN may turn into an EOF or error.) */
    else if ((Uint32) rc < internal->buffer_size)
        sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;

    return((Uint32) rc);
} /* OGG_read */

/* end of ogg.c ... */