/*****************************************************************************

 * fragments.c : MP4 fragments

 *****************************************************************************

 * Copyright (C) 2001-2015 VLC authors and VideoLAN

 *

 * This program 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 program 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 program; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

 *****************************************************************************/

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include "fragments.h"

#include <limits.h>

void MP4_Fragments_Index_Delete( mp4_fragments_index_t *p_index )

{

    if( p_index )

    {

        free( p_index->pi_pos );

        free( p_index->p_times );

        free( p_index );

    }

}

mp4_fragments_index_t * MP4_Fragments_Index_New( unsigned i_tracks, unsigned i_num )

{

    if( !i_tracks || !i_num || SIZE_MAX / i_num < i_tracks )

        return NULL;

    mp4_fragments_index_t *p_index = malloc( sizeof(*p_index) );

    if( p_index )

    {

        p_index->p_times = calloc( (size_t)i_num * i_tracks, sizeof(*p_index->p_times) );

        p_index->pi_pos = calloc( i_num, sizeof(*p_index->pi_pos) );

        if( !p_index->p_times || !p_index->pi_pos )

        {

            MP4_Fragments_Index_Delete( p_index );

            return NULL;

        }

        p_index->i_entries = i_num;

        p_index->i_last_time = 0;

        p_index->i_tracks = i_tracks;

    }

    return p_index;

}

stime_t MP4_Fragment_Index_GetTrackStartTime( mp4_fragments_index_t *p_index,

                                              unsigned i_track_index, uint64_t i_moof_pos )

{

    for( size_t i=0; i<p_index->i_entries; i++ )

    {

        if( p_index->pi_pos[i] >= i_moof_pos )

            return p_index->p_times[i * p_index->i_tracks + i_track_index];

    }

    return 0;

}

stime_t MP4_Fragment_Index_GetTracksDuration( const mp4_fragments_index_t *p_index )

{

    return p_index->i_last_time;

}

bool MP4_Fragments_Index_Lookup( mp4_fragments_index_t *p_index, stime_t *pi_time,

                                 uint64_t *pi_pos, unsigned i_track_index )

{

    if( *pi_time >= p_index->i_last_time || p_index->i_entries < 1 ||

        i_track_index >= p_index->i_tracks )

        return false;

    for( size_t i=1; i<p_index->i_entries; i++ )

    {

        if( p_index->p_times[i * p_index->i_tracks + i_track_index] > *pi_time )

        {

            *pi_time = p_index->p_times[(i - 1) * p_index->i_tracks + i_track_index];

            *pi_pos = p_index->pi_pos[i - 1];

            return true;

        }

    }

    *pi_time = p_index->p_times[(size_t)(p_index->i_entries - 1) * p_index->i_tracks];

    *pi_pos = p_index->pi_pos[p_index->i_entries - 1];

    return true;

}

#ifdef MP4_VERBOSE

static inline int64_t movietime_to_ms(stime_t time, uint32_t i_movie_timescale)

{

    if( i_movie_timescale == INT64_C( 1000 ) )

        return time;

    if( time <= INT64_MAX / INT64_C( 1000 ) )

        return time * INT64_C( 1000 ) / i_movie_timescale;

    /* overflow */

    int64_t q = time / i_movie_timescale;

    int64_t r = time % i_movie_timescale;

    return q * INT64_C( 1000 ) + r * INT64_C( 1000 ) / i_movie_timescale;

}

void MP4_Fragments_Index_Dump( vlc_object_t *p_obj, const mp4_fragments_index_t *p_index,

                               uint32_t i_movie_timescale )

{

    for( size_t i=0; i<p_index->i_entries; i++ )

    {

        char *psz_starts = NULL;

        stime_t i_end;

        if( i + 1 == p_index->i_entries )

            i_end = p_index->i_last_time;

        else

            i_end = p_index->p_times[(i + 1) * p_index->i_tracks];

        for( unsigned j=0; j<p_index->i_tracks; j++ )

        {

            char *psz_start = NULL;

            if( 0 < asprintf( &psz_start, "%s [%u]%"PRId64"ms ",

                      (psz_starts) ? psz_starts : "", j,

                  movietime_to_ms(p_index->p_times[i * p_index->i_tracks + j], i_movie_timescale) ) )

            {

                free( psz_starts );

                psz_starts = psz_start;

            }

        }

        msg_Dbg( p_obj, "fragment offset @%"PRId64" %"PRId64"ms, start %s",

                 p_index->pi_pos[i],

                 movietime_to_ms( i_end, i_movie_timescale ), psz_starts );

        free( psz_starts );

    }

}

#endif