SDR-DAB_Qt-DAB/sources/backend/data/pad-handler.cpp

#
/*
 *    Copyright (C) 2015 .. 2023
 *    Jan van Katwijk (J.vanKatwijk@gmail.com)
 *    Lazy Chair Computing
 *
 *    This file is part of the Qt-DAB
 *
 *    Qt-DAB is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    Qt-DAB 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with Qt-DAB; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//#define	_PAD_TRACE_
#include	"pad-handler.h"
#include	<cstring>
#include	"radio.h"
#include	"crc-handlers.h"
#include	"charsets.h"
#include	"mot-object.h"
/**
  *	\class padHandler
  *	Handles the pad segments passed on from mp2- and mp4Processor
  */
	padHandler::padHandler	(RadioInterface *mr,
	                            bool backgroundFlag):
	                              myRadioInterface (mr) {
	this	-> backgroundFlag	= backgroundFlag;

	connect (this, &padHandler::show_label,
	         mr, &RadioInterface::show_label);
	connect (this, &padHandler::show_mothandling,
	         mr, &RadioInterface::show_mothandling);
	connect (this, &padHandler::show_title,
	         mr, &RadioInterface::show_title);
//	currentSlide	= nullptr;
//
//	mscGroupElement indicates whether we are handling an
//	msc datagroup or not.
	mscGroupElement	= false;
	dataGroupLength	= 0;

//	xpadLength tells - if mscGroupElement is "on" - the size of the
//	xpadfields, needed for handling xpads without CI's
	xpadLength	= -1;
//
//	and for the shortPad we maintain
	still_to_go	= 0;
	lastSegment	= false;
	firstSegment	= false;
	segmentNumber	= -1;
//
//
	segmentno		= -1;
	remainDataLength	= 0;
	isLastSegment		= false;
	moreXPad		= false;

	the_DL2. dlsText	= "";
	the_DL2. IT		= 10;
	the_DL2. IR		= 10;
	for (int i = 0; i < 4; i ++)
	   the_DL2. entity [i]. ct = 65;
}

	padHandler::~padHandler() {
//	if (currentSlide != nullptr)
//	   delete currentSlide;
}

//	Data is stored reverse, we pass the vector and the index of the
//	last element of the XPad data.
//	 L0 is the "top" byte of the L field, L1 the next to top one.
void	padHandler::processPAD (const uint8_t *buffer, int16_t last,
	                        uint8_t L1, uint8_t L0) {
uint8_t	fpadType	= (L1 >> 6) & 03;

	if (fpadType != 00) {
//	   fprintf (stderr, "fPadtype = %x_padInd\n");
	   return;
	}
//
//	OK, we'll try
	
	uint8_t x_padInd	= (L1 >> 4) & 03;
	uint8_t CI_flag         = L0 & 02;

	switch (x_padInd) {
	   default:
	      break;

	   case  01 :
	      handle_shortPAD	 (buffer, last, CI_flag);
	      break;

	   case  02:
	      handle_variablePAD (buffer, last, CI_flag);
	      break;
	}
}
//	Since the data is stored in reversed order, we pass
//	on the vector address and the offset of the last element
//	in that vector
//
//	shortPad's are 4  byte values. If the CI is on, then type 2
//	indicates the start of a segment. Type 3 the continuation.
//	The start of a message, i.e. segment 0 is (a.o) found by
//	a (1, 0) value of the firstSegment/lastSegment values.
//	The end of a segment might be indicated by a specific pattern
//	of these 2 values, but it is not clear to me how.
//	For me, the end of a segment is when we collected the amount
//	of values specified for the segment.
void	padHandler::handle_shortPAD (const uint8_t *b,
	                             int16_t last, uint8_t CIf) {
int16_t	i;

	if (CIf != 0) {	// has a CI flag
	   uint8_t CI    = b [last];
	   firstSegment  = (b [last - 1] & 0x40) != 0;
	   lastSegment   = (b [last - 1] & 0x20) != 0;
	   charSet       = b [last - 2] & 0x0F;
	   uint8_t AcTy  = CI & 037;	// application type

	   if (firstSegment) 
	      dynamicLabelText. clear ();
	   switch (AcTy) {
	      default:
	         break;

	      case 0:	// end marker
	         break;
//
	      case 2:	// start of fragment, extract the length
	         if (firstSegment && !lastSegment) {
	            segmentNumber   = b [last - 2] >> 4;
	            if (dynamicLabelText. size () > 0) { 
	             QString displayText =  toQStringUsingCharset 
	                                  ((char *)(dynamicLabelText. data()),
	                                  (CharacterSet)charSet,
	                                  dynamicLabelText. size());
	               show_label (displayText, (int)charSet);
	            }
	            dynamicLabelText = "";
	         }
	         still_to_go     = b [last - 1] & 0x0F;
	         shortpadData. resize (0);
	         shortpadData. push_back (b [last - 3]);
	         break;

	      case 3:	// continuation of fragment
	         for (i = 0; (i < 3) && (still_to_go > 0); i ++) {
	            still_to_go --;
	            shortpadData. push_back (b [last - 1 - i]);
	         }

	         if ((still_to_go <= 0) && (shortpadData. size() > 1)) {
//	             shortpadData. push_back (0);
	             dynamicLabelText. append ((const char *)shortpadData. data (),
	                                       shortpadData. size ());
	             shortpadData. resize (0);
	         }
	         break;

	   }
	}
	else {	// No CI flag
 //	X-PAD field is all data
	   for (i = 0; (i < 4) && (still_to_go > 0); i ++) {
	      shortpadData. push_back (b [last - i]);
	      still_to_go --;
	   }

//	at the end of a frame
	   if ((still_to_go <= 0) && (shortpadData. size() > 0)) {
//	      shortpadData . push_back (0);
//
//	just to avoid doubling by unsollicited shortpads
	      dynamicLabelText. append ((const char *)shortpadData. data (),
	                                shortpadData. size ());
	      shortpadData. resize (0);
//	if we are at the end of the last segment (and the text is not empty)
//	then show it.
	      if (!firstSegment && lastSegment) {
	         if (dynamicLabelText. size() > 0) {
	            QString displayText =
	                      toQStringUsingCharset (
	                               (const char *)dynamicLabelText. data (),
	                               (CharacterSet) charSet,
	                               dynamicLabelText. size ());
//	            fprintf (stderr, "%s \n", displayText. toLatin1 (). data ());
	            show_label (displayText, (int)charSet);
	         }
	         dynamicLabelText. clear();
	      }
	   }
	}
}
///////////////////////////////////////////////////////////////////////
//
//	Here we end up when F_PAD type = 00 and X-PAD Ind = 02
static
int16_t	lengthTable [] = {4, 6, 8, 12, 16, 24, 32, 48};

//	Since the data is reversed, we pass on the vector address
//	and the offset of the last element in the vector,
//	i.e. we start (downwards)  beginning at b [last];
void	padHandler::handle_variablePAD (const uint8_t *b,
	                                int16_t last, uint8_t CI_flag) {
int16_t	CI_Index = 0;
uint8_t CI_table [4];
int16_t	base	= last;	
std::vector<uint8_t> data;		// for the local addition

//	If an xpadfield shows with a CI_flag == 0, and if we are
//	dealing with an msc field, the size to be taken is
//	the size of the latest xpadfield that had a CI_flag != 0
	if (CI_flag == 0) {
//	   if (mscGroupElement && (xpadLength > 0)) {
	   if (xpadLength > 0) {
	      if (last < xpadLength - 1) {
//	         fprintf(stderr, "handle_variablePAD: last < xpadLength - 1\n");
	         return;
	      }
	      
	      data. resize (xpadLength);
	      for (int16_t j = 0; j < xpadLength; j ++)
	         data [j] = b [last - j];
	      switch (last_appType) {
// Dynamic label segment, start of X-PAD data group
	         case 2:
// Dynamic label segment, continuation of X-PAD data group
	         case 3:
	            dynamicLabel((uint8_t *)(data.data()), xpadLength, 3);
	            break;

	         case 12:   // MOT, start of X-PAD data group
	         case 13:   // MOT, continuation of X-PAD data group
	            if (mscGroupElement)
	               add_MSC_element(data);
	            break;
	         default:
	            break;
	      }
	   }
	   return;
	}
//
//	The CI flag in the F_PAD data is set, so we have local CI's
//	7.4.2.2: Contents indicators are one byte long

	while (((b [base] & 037) != 0) && (CI_Index < 4))
	   CI_table [CI_Index ++] = b [base --];

	if (CI_Index < 4) 	// we have a "0" indicator, adjust base
	   base -= 1;

//	The space for the CI's does belong to the CPadfield, so
//	do not forget to take into account the '0'field if CI_Index < 4
//	if (mscGroupElement) {	
	{
	   xpadLength = 0;
	   for (int16_t i = 0; i < CI_Index; i ++)
	      xpadLength += lengthTable [CI_table [i] >> 5];
	   xpadLength += CI_Index == 4 ? 4 : CI_Index + 1;
//	   fprintf (stderr, "xpadLength set to %d\n", xpadLength);
	}

//	Handle the contents
	for (int16_t i = 0; i < CI_Index; i ++) {
	   uint8_t appType	= CI_table [i] & 037;
	   int16_t length	= lengthTable [CI_table [i] >> 5];

	   if (appType == 1) {	// length spec
	      dataGroupLength = ((b [base] & 077) << 8) | b [base - 1];
	      base -= 4;
	      last_appType = 1;
	      continue;
	   }

//	collect data, reverse the reversed bytes
	   data. resize (length);
	   for (int16_t j = 0; j < length; j ++)  
	      data [j] = b [base - j];

	   switch (appType) {
	      default:
	         return; // sorry, we do not handle this

	      case 1:	//
//	         fprintf (stderr, "Need to fix this\n");
	         return;
	      case 2:	// Dynamic label segment, start of X-PAD data group
	      case 3:	// Dynamic label segment, continuation of X-PAD data group
	         dynamicLabel ((uint8_t *)(data. data()),
	                        data. size(), CI_table [i]);
	         break;

	      case 12:	 // MOT, start of X-PAD data group
	         new_MSC_element (data);
	         break;

 	      case 13:	 // MOT, continuation of X-PAD data group
	         add_MSC_element (data);
	         break;
	   }

	   last_appType = appType;
	   base -= length;
	   if (base < 0 && i < CI_Index - 1) {
//	      fprintf (stderr, "Hier gaat het fout, base = %d\n", base);
	      return;
	   }
	}
}
//
//	A dynamic label is created from a sequence of (dynamic) xpad
//	fields, starting with CI = 2, continuing with CI = 3
void	padHandler::dynamicLabel (const uint8_t *data, int16_t length, uint8_t CI) {
int16_t  dataLength                = 0;

	if ((CI & 037) == 02) {	// start of segment
	   uint16_t prefix = (data [0] << 8) | data [1];
	   uint8_t field_1 = (prefix >> 8) & 017;
	   uint8_t Cflag   = (prefix >> 12) & 01;
	   uint8_t first   = (prefix >> 14) & 01;
	   uint8_t last    = (prefix >> 13) & 01;
	   dataLength	   = length - 2; // The length with header removed

#ifdef	_PAD_TRACE_
	   fprintf (stderr, "first %d last %d Cflag %d\n",
	                    first, last, Cflag);
#endif
	   if (first) { 
	      segmentno = 1;
#ifdef	_PAD_TRACE_
	      fprintf (stderr, "segment 1\n");
#endif
	      charSet = (prefix >> 4) & 017;
	      dynamicLabelText. clear ();
	   }
	   else {
	      int test = ((prefix >> 4) & 07) + 1;
	      if (test != segmentno + 1) {
#ifdef _PAD_TRACE_
	         fprintf (stderr, "mismatch %d %d\n", test, segmentno);
#endif
	         segmentno = -1;
	         return;
	      }
	      segmentno = ((prefix >> 4) & 07) + 1;
#ifdef _PAD_TRACE_
	      fprintf (stderr, "segment %d\n", segmentno);
#endif
	   }
//
//	etsi TS 102 980 specifies the DL plus objects, I just let it go
//	for the time being
 	  if (Cflag) {		// special dynamic label command
	      uint16_t Command = (prefix >> 8) & 0x0f;
	      switch (Command) {
	         case 1:
#ifdef	_PAD_TRACE_
	            fprintf (stderr, "clear command\n");
#endif
	            dynamicLabelText. clear ();
	            segmentno = -1;
	            break;
	         case 2:
#ifdef	_PAD_TRACE_
	            fprintf (stderr, "DL plus command\n");
#endif
	            if (!backgroundFlag)
	               add_toDL2 (&data [2]);
	            break;
	         default:
//	            fprintf (stderr, "unknown command %d\n", Command);
	            break;
	      }
	   }
	   else {		// Dynamic text length
	      int16_t totalDataLength = field_1 + 1;
	      if (length - 2 < totalDataLength) {
	         dataLength = length - 2; // the length is shortened by header
	         moreXPad   = true;
	      }
	      else {
	         dataLength = totalDataLength;  // no more xpad app's 3
	         moreXPad   = false;
	      }
//	convert dynamic label
	      dynamicLabelText. append ((const char *)(&data [2]), dataLength);

//	if at the end, show the label
	      if (last) {
	         if (!moreXPad) {
	            QString displayText =
	                     toQStringUsingCharset (
	                              (const char *) dynamicLabelText. data (),
	                              (CharacterSet) charSet,
	                              dynamicLabelText. size ());
	            if (!backgroundFlag) {
	               add_toDL2 (displayText);
	               show_label (displayText, (int)charSet);
	            }
	            segmentno = -1;
	         }
	         else
	            isLastSegment = true;
	      }
	      else 
	         isLastSegment = false;
//	calculate remaining data length
	      remainDataLength = totalDataLength - dataLength;
	   }
	}
	else 
	if (((CI & 037) == 03) && moreXPad) {
	   if (remainDataLength > length) {
	      dataLength = length;
	      remainDataLength -= length;
	   }
	   else {
	      dataLength = remainDataLength;
	      moreXPad   = false;
	   }
	   
	   dynamicLabelText. append ((const char *)data, dataLength);
	   if (!moreXPad && isLastSegment) {
	             QString displayText =  toQStringUsingCharset 
	                                  ((char *)(dynamicLabelText. data()),
	                                  (CharacterSet)charSet,
	                                  dynamicLabelText. size());
	             if (!backgroundFlag) {
	                add_toDL2 (displayText);
	                show_label (displayText, (int)charSet);
	             }
	   }
	}
}

//
//	Called at the start of the msc datagroupfield,
//	the msc_length was given by the preceding appType "1"
void	padHandler::new_MSC_element (const std::vector<uint8_t> &data) {

//	if (mscGroupElement) { 
////	   if (msc_dataGroupBuffer. size() < dataGroupLength)
////	      fprintf (stderr, "short ? %d %d\n",
////	                              msc_dataGroupBuffer. size(),
////	                              dataGroupLength);
//	   msc_dataGroupBuffer. clear();
//	   build_MSC_segment (data);
//	   mscGroupElement	= true;
//	   show_mothandling (true);
//	}

	if (data. size() >= (uint16_t)dataGroupLength) { // msc element is single item
	   msc_dataGroupBuffer. clear();
	   build_MSC_segment (data);
	   mscGroupElement = false;
	   show_mothandling (true);
//	   fprintf (stderr, "msc element is single\n");
	   return;
	}

	mscGroupElement		= true;
	msc_dataGroupBuffer. clear();
	msc_dataGroupBuffer	= data;
	show_mothandling (true);
}

//
void	padHandler::add_MSC_element	(const std::vector<uint8_t> &data) {
int32_t	currentLength = msc_dataGroupBuffer. size();
//
//	just to ensure that, when a "12" appType is missing, the
//	data of "13" appType elements is not endlessly collected.
	if (currentLength == 0) {
	   return;
	}

	msc_dataGroupBuffer. insert (std::end (msc_dataGroupBuffer),
	                             std::begin (data), std::end (data));
	if (msc_dataGroupBuffer. size() >= (uint32_t)dataGroupLength) {
	   build_MSC_segment (msc_dataGroupBuffer);
	   msc_dataGroupBuffer. clear();
//	   mscGroupElement	= false;
	   show_mothandling (false);
	}
}

void	padHandler::build_MSC_segment (const std::vector<uint8_t> &data) {
//	we have a MOT segment, let us look what is in it
//	according to DAB 300 401 (page 37) the header (MSC data group)
//	is
int32_t	size	= data. size() < (uint32_t)dataGroupLength ? data. size() :
	                                            dataGroupLength;

	if (size < 2) {
	   fprintf (stderr, "build_MSC_segment: data size < 2\n");
	   return;
	}
	   
const uint8_t	groupType	=  data [0] & 0xF;
//uint8_t	continuityIndex = (data [1] & 0xF0) >> 4;
//uint8_t	repetitionIndex =  data [1] & 0xF;
uint16_t	transportId	= 0;	// default
int16_t		segmentNumber	= -1;		// default
bool		lastFlag	= false;	// default
uint16_t	index;

	if ((data [0] & 0x40) != 0) {
	   bool res	= check_crc_bytes (data. data(), size - 2);
	   if (!res) {
//	      fprintf (stderr, "build_MSC_segment fails on crc check\n");
	      return;
	   }
//	   else
//	      fprintf (stderr, "crc success ");
	}

	if ((groupType != 3) && (groupType != 4)) {
//	   fprintf (stderr, "groupType %d\n", groupType);
	   return;		// do not know yet
	}
//	extensionflag
	bool	extensionFlag	= (data [0] & 0x80) != 0;
//	if the segmentflag is on, then a lastflag and segmentnumber are
//	available, i.e. 2 bytes more.
//	Theoretically, the segment number can be as large as 16384
	index			= extensionFlag ? 4 : 2;
	bool	segmentFlag	=  (data [0] & 0x20) != 0;
	if ((segmentFlag) != 0) {
	   lastFlag		= data [index] & 0x80;
	   segmentNumber	= ((data [index] & 0x7F) << 8) |
	                                               data [index + 1];
	   index += 2;
	}

//	if the user access flag is on there is a user accessfield
	if ((data [0] & 0x10) != 0) {
	   int16_t lengthIndicator = data [index] & 0x0F;
	   if ((data [index] & 0x10) != 0) { //transportid flag
	      transportId = data [index + 1] << 8 |
	                    data [index + 2];
//	      fprintf (stderr, "transportId = %d\n", transportId);
	      index += 3;
	   }
//	   else {
//	      fprintf (stderr, "sorry no transportId\n");
//	      return;
//	   }
	   index += (lengthIndicator - 2);
	}

//	if (transportId == 0)	// no idea wat it means
//	   return;

	uint32_t segmentSize	= ((data [index + 0] & 0x1F) << 8) |
	                            data [index + 1];

//	handling MOT in the PAD, we only deal here with type 3/4
	switch (groupType) {
	   case 3:
	      if (currentSlide == nullptr) {
//	         fprintf (stderr, "creating %d\n", transportId);
	         currentSlide. reset (new motObject (myRadioInterface,
	                                         false,
	   	                                 transportId,
	                                         &data [index + 2],
	                                         segmentSize,
	                                         lastFlag,
	                                         backgroundFlag));
	      }
	      else {
	         if (currentSlide -> get_transportId() == transportId)
	            break;
//	         fprintf (stderr, "out goes %d, in comes %d\n",
//	                          currentSlide -> get_transportId(),
//	                                           transportId);
//	         delete currentSlide;
	         currentSlide. reset (new motObject (myRadioInterface,
	                                         false,
	   	                                 transportId,
	                                         &data [index + 2],
	                                         segmentSize,
	                                         lastFlag,
	                                         backgroundFlag
	                                       ));
	      }
	      break;

	   case 4:
	      if (currentSlide == nullptr)
	         return;
	      if (currentSlide -> get_transportId() == transportId) {
//	         fprintf (stderr, "add segment %d of  %d\n",
//	                           segmentNumber, transportId);
	         currentSlide -> addBodySegment (&data [index + 2],
	                                         segmentNumber,
	                                         segmentSize,
	                                         lastFlag);
	      }
	      break;

	   default:		// cannot happen
	      fprintf (stderr, "Not yet handled mot in pad %d (%X)\n",
	                                          groupType, transportId);
	      break;
	}
}


void	padHandler::add_toDL2 (const QString &text) {
	if (the_DL2. dlsText != text) {
	   the_DL2. dlsText = text;
//	   fprintf (stderr, "dl2 fragment %s\n", text. toLatin1 (). data ());
	   the_DL2. valid = true;	// non existent key
	   for (int i = 0; i < 4; i ++)
	      the_DL2. entity [i]. ct = 65;
	}
}

void	padHandler::add_toDL2 (const uint8_t *data) {
int IT	= (data [0] & 0x08) >> 3;
int IR	= (data [2] & 0x04) >> 2; 
//int NT	= data [2] & 0x03;

	if ((the_DL2. IT == IT) && (the_DL2. IR == IR))
	   return;

	if (the_DL2. IT != IT) {	// toggle bit changed
	   the_DL2. IT = IT;
//	   if (IR != 0)
//	      fprintf (stderr, "Show a message\n");
//	   else
//	      fprintf (stderr, "hide a message\n");
	}
	else
	if (the_DL2. IR != IR) {
//	   if (IR == 0)
//	      fprintf (stderr, "Stop met de message\n");
//	   else
//	      fprintf (stderr, "Restart de message\n");
	   the_DL2. IR = IR;
	}
}