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

 * a52.c: parse A/52 audio sync info and packetize the stream

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

 * Copyright (C) 2001-2016 VLC authors and VideoLAN

 *

 * Authors: Stéphane Borel <stef@via.ecp.fr>

 *          Christophe Massiot <massiot@via.ecp.fr>

 *          Gildas Bazin <gbazin@videolan.org>

 *

 * 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.

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

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

 * Preamble

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

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include <assert.h>

#include <vlc_common.h>

#include <vlc_plugin.h>

#include <vlc_codec.h>

#include <vlc_block_helper.h>

#include <vlc_modules.h>

#include "a52.h"

#include "packetizer_helper.h"

static int  Open( vlc_object_t * );

static void Close( vlc_object_t * );

vlc_module_begin ()

    set_subcategory(SUBCAT_SOUT_PACKETIZER)

    set_description( N_("A/52 audio packetizer") )

    set_capability( "audio packetizer", 10 )

    set_callbacks( Open, Close )

vlc_module_end ()

static const uint8_t startcode[2] = { 0x0b, 0x77 };

typedef struct

{

    /*

     * Input properties

     */

    int i_state;

    block_bytestream_t bytestream;

    /*

     * Common properties

     */

    date_t  end_date;

    vlc_tick_t i_prev_bytestream_pts;

    bool    b_discontuinity;

    vlc_a52_header_t frame;

    size_t  i_input_size;

} decoder_sys_t;

static void PacketizeFlush( decoder_t *p_dec )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    p_sys->b_discontuinity = true;

    date_Set( &p_sys->end_date, VLC_TICK_INVALID );

    p_sys->i_state = STATE_NOSYNC;

    p_sys->i_prev_bytestream_pts = VLC_TICK_INVALID;

    block_BytestreamEmpty( &p_sys->bytestream );

}

static block_t *GetOutBuffer( decoder_t *p_dec )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    assert( p_sys->frame.i_rate > 0 );

    block_t *p_block = block_Alloc( p_sys->i_input_size );

    if( p_block == NULL )

        return NULL;

    if( p_dec->fmt_out.audio.i_rate != p_sys->frame.i_rate )

    {

        msg_Dbg( p_dec, "A/52 channels:%d samplerate:%d bitrate:%d",

                 p_sys->frame.i_channels, p_sys->frame.i_rate, p_sys->frame.i_bitrate );

        if( p_sys->end_date.i_divider_num )

            date_Change( &p_sys->end_date, p_sys->frame.i_rate, 1 );

        else

            date_Init( &p_sys->end_date, p_sys->frame.i_rate, 1 );

    }

    block_t *p_bshead = p_sys->bytestream.p_block;

    /* Ensure we can recover if there's only dts set */

    if( date_Get( &p_sys->end_date ) == VLC_TICK_INVALID && p_bshead->i_pts == VLC_TICK_INVALID )

        p_bshead->i_pts = p_bshead->i_dts;

    if( p_bshead->i_pts != VLC_TICK_INVALID && p_bshead->i_pts != date_Get( &p_sys->end_date ) )

    {

        /* Make sure we don't reuse the same pts twice

         * as A/52 in PES sends multiple times the same pts */

        if( p_sys->bytestream.p_block->i_pts != p_sys->i_prev_bytestream_pts )

        {

            date_t tempdate = p_sys->end_date;

            date_Increment( &tempdate, p_sys->frame.i_samples );

            vlc_tick_t samplesduration = date_Get( &tempdate ) - date_Get( &p_sys->end_date );

            if( llabs(p_sys->bytestream.p_block->i_pts  - date_Get( &p_sys->end_date )) > samplesduration )

                date_Set( &p_sys->end_date, p_sys->bytestream.p_block->i_pts );

            p_sys->i_prev_bytestream_pts = p_sys->bytestream.p_block->i_pts;

            p_sys->bytestream.p_block->i_pts = VLC_TICK_INVALID;

        }

    }

    p_dec->fmt_out.audio.i_rate     = p_sys->frame.i_rate;

    p_dec->fmt_out.audio.i_channels = p_sys->frame.i_channels;

    if( p_dec->fmt_out.audio.i_bytes_per_frame < p_sys->frame.i_size )

        p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->frame.i_size;

    p_dec->fmt_out.audio.i_frame_length = p_sys->frame.i_samples;

    p_dec->fmt_out.audio.i_chan_mode = p_sys->frame.i_chan_mode;

    p_dec->fmt_out.audio.i_physical_channels = p_sys->frame.i_channels_conf;

    p_dec->fmt_out.i_bitrate = p_sys->frame.i_bitrate;

    p_block->i_nb_samples = p_sys->frame.i_samples;

    p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date );

    if( p_block->i_pts != VLC_TICK_INVALID )

        p_block->i_length = date_Increment( &p_sys->end_date,

                                            p_block->i_nb_samples ) - p_block->i_pts;

    return p_block;

}

static block_t *PacketizeBlock( decoder_t *p_dec, block_t **pp_block )

{

    decoder_sys_t *p_sys = p_dec->p_sys;

    uint8_t p_header[VLC_A52_MIN_HEADER_SIZE];

    block_t *p_out_buffer;

    block_t *p_block = pp_block ? *pp_block : NULL;

    if( p_block )

    {

        if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY | BLOCK_FLAG_CORRUPTED) )

        {

            /* First always drain complete blocks before discontinuity */

            block_t *p_drain = PacketizeBlock( p_dec, NULL );

            if(p_drain)

                return p_drain;

            PacketizeFlush( p_dec );

            if( p_block->i_flags & BLOCK_FLAG_CORRUPTED )

            {

                block_Release( p_block );

                return NULL;

            }

        }

        block_BytestreamPush( &p_sys->bytestream, p_block );

    }

    while( 1 )

    {

        switch( p_sys->i_state )

        {

        case STATE_NOSYNC:

            while( block_PeekBytes( &p_sys->bytestream, p_header, sizeof(startcode) )

                   == VLC_SUCCESS )

            {

                if( !memcmp(p_header, startcode, sizeof(startcode)) )

                {

                    p_sys->i_state = STATE_SYNC;

                    break;

                }

                block_SkipByte( &p_sys->bytestream );

            }

            if( p_sys->i_state != STATE_SYNC )

            {

                block_BytestreamFlush( &p_sys->bytestream );

                /* Need more data */

                return NULL;

            }

            /* fallthrough */

        case STATE_SYNC:

            p_sys->i_state = STATE_HEADER;

            /* fallthrough */

        case STATE_HEADER:

            /* Get A/52 frame header (VLC_A52_HEADER_SIZE bytes) */

            if( block_PeekBytes( &p_sys->bytestream, p_header,

                                 VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )

            {

                /* Need more data */

                return NULL;

            }

            /* Check if frame is valid and get frame info */

            if( vlc_a52_header_Parse( &p_sys->frame, p_header,

                                      VLC_A52_MIN_HEADER_SIZE ) != VLC_SUCCESS )

            {

                msg_Dbg( p_dec, "emulated sync word" );

                block_SkipByte( &p_sys->bytestream );

                p_sys->i_state = STATE_NOSYNC;

                break;

            }

            if( p_sys->frame.b_eac3 && p_sys->frame.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )

            {

                msg_Warn( p_dec, "starting with dependent stream, skip it" );

                p_sys->i_state = STATE_NOSYNC;

                if( block_SkipBytes( &p_sys->bytestream,

                                     p_sys->frame.i_size ) != VLC_SUCCESS )

                    return NULL;

                break;

            }

            p_sys->i_input_size = p_sys->frame.i_size;

            p_sys->i_state = STATE_NEXT_SYNC;

            /* fallthrough */

        case STATE_NEXT_SYNC:

            /* Check if next expected frame contains the sync word */

            if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_input_size,

                                       p_header, VLC_A52_MIN_HEADER_SIZE )

                                       != VLC_SUCCESS )

            {

                if( p_block == NULL ) /* drain */

                {

                    p_sys->i_state = STATE_GET_DATA;

                    break;

                }

                /* Need more data */

                return NULL;

            }

            if( p_header[0] == 0 || p_header[1] == 0 )

            {

                /* A52 wav files and audio CD's use stuffing */

                p_sys->i_state = STATE_GET_DATA;

                break;

            }

            if( memcmp(p_header, startcode, sizeof(startcode)) )

            {

                msg_Dbg( p_dec, "emulated sync word "

                         "(no sync on following frame)" );

                size_t offset = VLC_A52_MIN_HEADER_SIZE;

                if( !block_FindStartcodeFromOffset( &p_sys->bytestream, &offset,

                                                    startcode, sizeof(startcode),

                                                    NULL, NULL ) )

                {

                    if( offset < p_sys->i_input_size )

                        p_sys->i_input_size = offset;

                    /* else will resync after read */

                }

                else

                {

                    p_sys->i_state = STATE_NOSYNC;

                    block_SkipByte( &p_sys->bytestream );

                    break;

                }

            }

            vlc_a52_header_t a52;

            if( !vlc_a52_header_Parse( &a52, p_header, VLC_A52_MIN_HEADER_SIZE )

             && a52.b_eac3 && a52.bs.eac3.strmtyp == EAC3_STRMTYP_DEPENDENT )

            {

                p_sys->i_input_size += a52.i_size;

                p_dec->fmt_out.i_codec = VLC_CODEC_A52;

                p_dec->fmt_out.i_profile = VLC_A52_PROFILE_EAC3_DEPENDENT;

            }

            p_sys->i_state = STATE_GET_DATA;

            break;

        case STATE_GET_DATA:

            /* Make sure we have enough data. */

            if( block_WaitBytes( &p_sys->bytestream,

                                 p_sys->i_input_size ) != VLC_SUCCESS )

            {

                /* Need more data */

                return NULL;

            }

            p_sys->i_state = STATE_SEND_DATA;

            /* fallthrough */

        case STATE_SEND_DATA:

            if( !(p_out_buffer = GetOutBuffer( p_dec )) )

            {

                return NULL;

            }

            /* Copy the whole frame into the buffer. When we reach this point

             * we already know we have enough data available. */

            block_GetBytes( &p_sys->bytestream, p_out_buffer->p_buffer,

                            p_out_buffer->i_buffer );

            p_sys->i_state = STATE_NOSYNC;

            if( p_out_buffer->i_dts == VLC_TICK_INVALID )

            {

                block_Release( p_out_buffer );

                return NULL;

            }

            if( p_sys->b_discontuinity )

            {

                p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY;

                p_sys->b_discontuinity = false;

            }

            /* So p_block doesn't get re-added several times */

            if( pp_block )

                *pp_block = block_BytestreamPop( &p_sys->bytestream );

            return p_out_buffer;

        }

    }

}

static void Close( vlc_object_t *p_this )

{

    decoder_t *p_dec = (decoder_t*)p_this;

    decoder_sys_t *p_sys = p_dec->p_sys;

    block_BytestreamRelease( &p_sys->bytestream );

    free( p_sys );

}

static int Open( vlc_object_t *p_this )

{

    decoder_t *p_dec = (decoder_t*)p_this;

    decoder_sys_t *p_sys;

    switch( p_dec->fmt_in->i_codec )

    {

    case VLC_CODEC_EAC3:

    case VLC_CODEC_A52:

        break;

    default:

        return VLC_EGENERIC;

    }

    /* Allocate the memory needed to store the decoder's structure */

    if( ( p_dec->p_sys = p_sys =

          (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL )

        return VLC_ENOMEM;

    /* Misc init */

    p_sys->i_state = STATE_NOSYNC;

    date_Set( &p_sys->end_date, VLC_TICK_INVALID );

    p_sys->b_discontuinity = false;

    p_sys->i_prev_bytestream_pts = VLC_TICK_INVALID;

    memset(&p_sys->frame, 0, sizeof(vlc_a52_header_t));

    block_BytestreamInit( &p_sys->bytestream );

    /* Set output properties (Passthrough ONLY) */

    p_dec->fmt_out.i_codec = p_dec->fmt_in->i_codec;

    p_dec->fmt_out.audio = p_dec->fmt_in->audio;

    p_dec->fmt_out.audio.i_rate = 0;

    /* Set callback */

    p_dec->pf_packetize = PacketizeBlock;

    p_dec->pf_flush     = PacketizeFlush;

    p_dec->pf_get_cc    = NULL;

    return VLC_SUCCESS;

}