vcd.c

VLC媒体播放程序

    for ( i_index = 0 ; i_index < i_blocks ; i_index++ )
    {
        if ( ioctl_ReadSectors( VLC_OBJECT(p_input), p_vcd->vcddev,
             p_vcd->i_sector, p_buffer + i_index * VCD_DATA_SIZE, 1,
             VCD_TYPE ) < 0 )
        {
            msg_Err( p_input, "could not read sector %d", p_vcd->i_sector );
            return -1;
        }

        p_vcd->i_sector ++;
        if ( p_vcd->i_sector == p_vcd->p_sectors[p_vcd->i_track + 1] )
        {
            input_area_t *p_area;

            if ( p_vcd->i_track >= p_vcd->i_nb_tracks - 1 )
                return 0; /* EOF */

            vlc_mutex_lock( &p_input->stream.stream_lock );
            p_area = p_input->stream.pp_areas[
                    p_input->stream.p_selected_area->i_id + 1 ];

            msg_Dbg( p_input, "new title" );

            p_area->i_part = 1;
            VCDSetArea( p_input, p_area );
            vlc_mutex_unlock( &p_input->stream.stream_lock );
        }

        /* Update chapter */
        else if( p_vcd->b_valid_ep &&
                /* FIXME kludge so that read does not update chapter
                 * when a manual chapter change was requested and not
                 * yet accomplished */
                !p_input->stream.p_new_area )
        {
            int i_entry;

            vlc_mutex_lock( &p_input->stream.stream_lock );
            i_entry = p_input->stream.p_selected_area->i_plugin_data
                /* 1st entry point of the track (area)*/
                        + p_input->stream.p_selected_area->i_part - 1;
            if( i_entry + 1 < p_vcd->i_entries_nb &&
                    p_vcd->i_sector >= p_vcd->p_entries[i_entry + 1] )
            {
                vlc_value_t val;

                msg_Dbg( p_input, "new chapter" );
                p_input->stream.p_selected_area->i_part ++;

                /* Update the navigation variables without triggering
                 * a callback */
                val.i_int = p_input->stream.p_selected_area->i_part;
                var_Change( p_input, "chapter", VLC_VAR_SETVALUE, &val, NULL );
            }
            vlc_mutex_unlock( &p_input->stream.stream_lock );
        }

        i_read += VCD_DATA_SIZE;
    }

    if ( i_len % VCD_DATA_SIZE ) /* this should not happen */
    {
        if ( ioctl_ReadSectors( VLC_OBJECT(p_input), p_vcd->vcddev,
             p_vcd->i_sector, p_last_sector, 1, VCD_TYPE ) < 0 )
        {
            msg_Err( p_input, "could not read sector %d", p_vcd->i_sector );
            return -1;
        }

        p_input->p_vlc->pf_memcpy( p_buffer + i_blocks * VCD_DATA_SIZE,
                                   p_last_sector, i_len % VCD_DATA_SIZE );
        i_read += i_len % VCD_DATA_SIZE;
    }

    return i_read;
}

/*****************************************************************************
 * VCDSetProgram: Does nothing since a VCD is mono_program
 *****************************************************************************/
static int VCDSetProgram( input_thread_t * p_input,
                          pgrm_descriptor_t * p_program)
{
    return 0;
}

/*****************************************************************************
 * VCDSetArea: initialize input data for title x, chapter y.
 * It should be called for each user navigation request.
 ****************************************************************************/
static int VCDSetArea( input_thread_t * p_input, input_area_t * p_area )
{
    thread_vcd_data_t *     p_vcd;
    vlc_value_t val;

    p_vcd = (thread_vcd_data_t*)p_input->p_access_data;

    /* we can't use the interface slider until initilization is complete */
    p_input->stream.b_seekable = 0;

    if( p_area != p_input->stream.p_selected_area )
    {
        unsigned int i;

        /* Reset the Chapter position of the current title */
        p_input->stream.p_selected_area->i_part = 1;
        p_input->stream.p_selected_area->i_tell = 0;

        /* Change the default area */
        p_input->stream.p_selected_area = p_area;

        /* Change the current track */
        /* The first track is not a valid one  */
        p_vcd->i_track = p_area->i_id;
        p_vcd->i_sector = p_vcd->p_sectors[p_vcd->i_track];

        /* Update the navigation variables without triggering a callback */
        val.i_int = p_area->i_id;
        var_Change( p_input, "title", VLC_VAR_SETVALUE, &val, NULL );
        var_Change( p_input, "chapter", VLC_VAR_CLEARCHOICES, NULL, NULL );
        for( i = 1; i <= p_area->i_part_nb; i++ )
        {
            val.i_int = i;
            var_Change( p_input, "chapter", VLC_VAR_ADDCHOICE, &val, NULL );
        }
    }

    if( p_vcd->b_valid_ep )
    {
        int i_entry = p_area->i_plugin_data /* 1st entry point of
                                               the track (area)*/
                            + p_area->i_part - 1;
        p_vcd->i_sector = p_vcd->p_entries[i_entry];
    }
    else
        p_vcd->i_sector = p_vcd->p_sectors[p_vcd->i_track];

    p_input->stream.p_selected_area->i_tell =
        (off_t)p_vcd->i_sector * (off_t)VCD_DATA_SIZE
         - p_input->stream.p_selected_area->i_start;

    /* warn interface that something has changed */
    p_input->stream.b_seekable = 1;
    p_input->stream.b_changed = 1;

    /* Update the navigation variables without triggering a callback */
    val.i_int = p_area->i_part;
    var_Change( p_input, "chapter", VLC_VAR_SETVALUE, &val, NULL );

    return 0;
}

/****************************************************************************
 * VCDSeek
 ****************************************************************************/
static void VCDSeek( input_thread_t * p_input, off_t i_off )
{
    thread_vcd_data_t * p_vcd;
    unsigned int i_index;

    p_vcd = (thread_vcd_data_t *) p_input->p_access_data;

    p_vcd->i_sector = p_vcd->p_sectors[p_vcd->i_track]
                       + i_off / (off_t)VCD_DATA_SIZE;

    vlc_mutex_lock( &p_input->stream.stream_lock );
#define p_area p_input->stream.p_selected_area
    /* Find chapter */
    if( p_vcd->b_valid_ep )
    {
        for( i_index = 2 ; i_index <= p_area->i_part_nb; i_index ++ )
        {
            if( p_vcd->i_sector < p_vcd->p_entries[p_area->i_plugin_data
                + i_index - 1] )
            {
                vlc_value_t val;

                p_area->i_part = i_index - 1;

                /* Update the navigation variables without triggering
                 * a callback */
                val.i_int = p_area->i_part;
                var_Change( p_input, "chapter", VLC_VAR_SETVALUE, &val, NULL );
                break;
            }
        }
    }
#undef p_area

    p_input->stream.p_selected_area->i_tell =
        (off_t)p_vcd->i_sector * (off_t)VCD_DATA_SIZE
         - p_input->stream.p_selected_area->i_start;
    vlc_mutex_unlock( &p_input->stream.stream_lock );
}

/*****************************************************************************
 * VCDEntryPoints: Reads the information about the entry points on the disc.
 *****************************************************************************/
static int VCDEntryPoints( input_thread_t * p_input )
{
    thread_vcd_data_t *               p_vcd;
    byte_t *                          p_sector;
    entries_sect_t                    entries;
    uint16_t                          i_nb;
    int                               i, i_entry_index = 0;
    int                               i_previous_track = -1;

    p_vcd = (thread_vcd_data_t *) p_input->p_access_data;

    p_sector = malloc( VCD_DATA_SIZE * sizeof( byte_t ) );
    if( p_sector == NULL )
    {
        msg_Err( p_input, "not enough memory for entry points treatment" );
        return -1;
    }

    if( ioctl_ReadSectors( VLC_OBJECT(p_input), p_vcd->vcddev,
        VCD_ENTRIES_SECTOR, p_sector, 1, VCD_TYPE ) < 0 )
    {
        msg_Err( p_input, "could not read entry points sector" );
        free( p_sector );
        return( -1 );
    }

    memcpy( &entries, p_sector, CD_SECTOR_SIZE );
    free( p_sector );

    if( (i_nb = U16_AT( &entries.i_entries_nb )) > 500 )
    {
        msg_Err( p_input, "invalid entry points number" );
        return( -1 );
    }

    p_vcd->p_entries = malloc( sizeof( int ) * i_nb );
    if( p_vcd->p_entries == NULL )
    {
        msg_Err( p_input, "not enough memory for entry points treatment" );
        return -1;
    }

    if( strncmp( entries.psz_id, "ENTRYVCD", sizeof( entries.psz_id ) )
     && strncmp( entries.psz_id, "ENTRYSVD", sizeof( entries.psz_id ) ))
    {
        msg_Err( p_input, "unrecognized entry points format" );
        free( p_vcd->p_entries );
        return -1;
    }

    p_vcd->i_entries_nb = 0;

#define i_track BCD_TO_BIN(entries.entry[i].i_track)
    /* Reset the i_part_nb for each track */
    for( i = 0 ; i < i_nb ; i++ )
    {
        if( i_track <= p_input->stream.i_area_nb )
        {
            p_input->stream.pp_areas[i_track-1]->i_part_nb = 0;
        }
    }

    for( i = 0 ; i < i_nb ; i++ )
    {
        if( i_track <= p_input->stream.i_area_nb )
        {
            p_vcd->p_entries[i_entry_index] =
                (MSF_TO_LBA2( BCD_TO_BIN( entries.entry[i].msf.minute ),
                              BCD_TO_BIN( entries.entry[i].msf.second ),
                              BCD_TO_BIN( entries.entry[i].msf.frame  ) ));
            p_input->stream.pp_areas[i_track-1]->i_part_nb ++;
            /* if this entry belongs to a new track */
            if( i_track != i_previous_track )
            {
                /* i_plugin_data is used to store the first entry of the area*/
                p_input->stream.pp_areas[i_track-1]->i_plugin_data =
                                                            i_entry_index;
                i_previous_track = i_track;
            }
            msg_Dbg( p_input, "entry point %i begins at LBA: %i",
                     i_entry_index, p_vcd->p_entries[i_entry_index] );

            i_entry_index ++;
            p_vcd->i_entries_nb ++;
        }
        else
            msg_Warn( p_input, "wrong track number found in entry points" );
    }
#undef i_track
    return 0;
}