src/CoAP_EncDec.cc - titan/titan.ProtocolModules.CoAP - Git at Google

 /******************************************************************************
 * Copyright (c) 2016  Ericsson AB
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Mate Kovacs - initial implementation and initial documentation
 *  Antal Wu-Hen Chang
 *  Naum Spaseski
 ******************************************************************************/
 //
 //  File:               CoAP_EncDec.cc
 //  Rev:                R1A
 //  Prodnr:             CNL 113 829

 #include "CoAP_Types.hh"

 namespace CoAP__Types {

 int getOptionCode(CoAP__Options option);
 int getOptionLength(CoAP__Options option);
 int getIntegerLength(const long long int value, int mode);
 void encodeInteger(TTCN_Buffer &stream, const long long int option, const int length);
 long long int decodeInteger(OCTETSTRING const &str, const int position, const int length);
 int getBlockLengthForNum(const long long int num);
 void encodeBlock(TTCN_Buffer &stream, const BlockOption option, const int length);
 void decodeBlock(BlockOption& block, OCTETSTRING const &str, const int position, const int length);

 INTEGER
 f__CoAP__dec(OCTETSTRING const &str, CoAP__Message &msg)
 {
   if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
     TTCN_Logger::begin_event(TTCN_DEBUG);
     TTCN_Logger::log_event("Decoding CoAP message: ");
     str.log();
     TTCN_Logger::end_event();
   }

   if(str.lengthof() >= 4){
     const unsigned char* str_ptr = (const unsigned char*) str;
     unsigned char chr;
     int position = 0;
     int token_length = 0;
     int actual_option_code = 0;
     int count_of_options = 0;
     bool payload_marker = false;

     //version, message type and token length
     chr = str_ptr[0];
     msg.msg().header().version() = chr >> 6;
     msg.msg().header().msg__type() = (chr >> 4) & 3;
     token_length = chr & 15;
     //code
     chr = str_ptr[1];
     msg.msg().header().code().class_() = (chr >> 5) & 7;
     msg.msg().header().code().detail() = chr & 31;
     //message ID
     msg.msg().header().message__id() = str_ptr[2] * 256 + str_ptr[3];

     if(str.lengthof() > 4 && msg.msg().header().code().class_() == 0 && msg.msg().header().code().detail() == 0){
 	  msg.raw__message() = str;
 	  return 1;
     }

     position = 4;
     //token
     if(token_length > 0){
       if(str.lengthof() >= position + token_length){
 	    msg.msg().token() = OCTETSTRING(token_length, &str_ptr[position]);
 	    position += token_length;
       }else{
         msg.raw__message() = str;
 	    return 1;
 	  }
     }else{
 	  msg.msg().token() = OCTETSTRING(0, 0);
     }

     //options
     msg.msg().options() = OMIT_VALUE;
     if(str.lengthof() > 4){
       while(!payload_marker && str.lengthof() > position){
         int delta = str_ptr[position] >> 4;
 	    int length = str_ptr[position] & 15;
 	    if(delta == 15 && length != 15){
 	      msg.raw__message() = str;
 	      return 1;
 	    }
         position++;
 	    if(delta == 15 && length == 15){
 	      payload_marker = true;
 	    }else{
 	      //optional delta
 	      if(delta == 13){
 	        delta = str_ptr[position] + 13;
 		    position++;
 	      }else if(delta == 14){
             delta = (str_ptr[position] << 8) + str_ptr[position+1] + 269;
 	        position += 2;
 	      }
 	      //optional length
 	      if(length == 13){
 		    length = str_ptr[position] + 13;
 		    position++;
 	      }else if(length == 14){
 		    length = (str_ptr[position] << 8) + str_ptr[position+1] + 269;
 		    position += 2;
 	      }else if(length == 15){
 	        msg.raw__message() = str;
 	        return 1;
 	      }

 	      //value
 	      actual_option_code += delta;
 	      switch(actual_option_code){
 	      case 1:
 	    	msg.msg().options()()[count_of_options].if__match() = OCTETSTRING(length, &str_ptr[position]);
 		    break;
 	      case 3:
 	    	msg.msg().options()()[count_of_options].uri__host().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 4:
 	    	msg.msg().options()()[count_of_options].etag() = OCTETSTRING(length, &str_ptr[position]);
 		    break;
           case 5:
             msg.msg().options()()[count_of_options].if__none__match() = OCTETSTRING(0, 0);
 		    break;
           case 6:
             msg.msg().options()()[count_of_options].observe().set_long_long_val(decodeInteger(str, position, length));
             break;
 	      case 7:
 		    msg.msg().options()()[count_of_options].uri__port().set_long_long_val(decodeInteger(str, position, length));
 		    break;
 	      case 8:
 	    	msg.msg().options()()[count_of_options].location__path().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 11:
 	    	msg.msg().options()()[count_of_options].uri__path().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 12:
 	        msg.msg().options()()[count_of_options].content__format().set_long_long_val(decodeInteger(str, position, length));
 	        break;
 	      case 14:
 		    msg.msg().options()()[count_of_options].max__age().set_long_long_val(decodeInteger(str, position, length));
 	        break;
 	      case 15:
 	    	msg.msg().options()()[count_of_options].uri__query().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 17:
 		    msg.msg().options()()[count_of_options].accept().set_long_long_val(decodeInteger(str, position, length));
 		    break;
 	      case 20:
 	    	msg.msg().options()()[count_of_options].location__query().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 23: // Block2 RFC 7959
 	    	decodeBlock(msg.msg().options()()[count_of_options].block2(), str, position, length);
 	    	break;
 	      case 27: // Block1 RFC 7959
 	    	decodeBlock(msg.msg().options()()[count_of_options].block1(), str, position, length);
 	    	break;
 	      case 35:
 	    	msg.msg().options()()[count_of_options].proxy__uri().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 39:
 	    	msg.msg().options()()[count_of_options].proxy__scheme().decode_utf8(length, &str_ptr[position]);
 		    break;
 	      case 60:
 		    msg.msg().options()()[count_of_options].size1().set_long_long_val(decodeInteger(str, position, length));
 		    break;
 	      default:
 		    msg.msg().options()()[count_of_options].unknown__option().option__code() = actual_option_code;
 		    msg.msg().options()()[count_of_options].unknown__option().option__value() = OCTETSTRING(length, &str_ptr[position]);
 		    break;
 	      }
 	      position += length;
 	      count_of_options++;
         }
       }
     }

     //payload
     if(str.lengthof() > position){
 	  msg.msg().payload() = OCTETSTRING(str.lengthof() - position, &str_ptr[position]);
 	  if(msg.msg().payload()().lengthof() == 0){
 	    msg.raw__message() = str;
 	    return 1;
 	  }
     }else{
 	  if(payload_marker){
 	    msg.raw__message() = str;
 	    return 1;
 	  }else{
 	    msg.msg().payload() = OMIT_VALUE;
 	  }
     }
   }else{
     msg.raw__message() = str;
     return 1;
   }

   if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
     TTCN_Logger::begin_event(TTCN_DEBUG);
     TTCN_Logger::log_event("Decoded CoAP message: ");
     msg.log();
     TTCN_Logger::end_event();
   }

   return 0;
 }

 INTEGER
 f__CoAP__enc(CoAP__Message const &msg, OCTETSTRING &str)
 {
   TTCN_Buffer stream;
   unsigned char chr = 0;

   if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
     TTCN_Logger::begin_event(TTCN_DEBUG);
     TTCN_Logger::log_event("Encoding CoAP message: ");
     msg.log();
     TTCN_Logger::end_event();
   }

   switch(msg.get_selection()){
   case CoAP__Message::ALT_raw__message:
 	  stream.put_os(msg.raw__message());
 	  stream.get_string(str);
 	  return 0;
 	  break;
   case CoAP__Message::ALT_msg:
   default:
 	  break;
   }

   //HEADER
     //version
   if(0 <= msg.msg().header().version() && msg.msg().header().version() <= 3){
     chr = msg.msg().header().version() << 6;
   }else{
 	return 1;
   }
     //message type
   chr += msg.msg().header().msg__type() << 4;
     //tkl (token length)
   if(msg.msg().token().lengthof() >= 0 && msg.msg().token().lengthof() <= 8){
     chr += msg.msg().token().lengthof();
   }else{
 	return 1;
   }
   stream.put_c(chr);
     //code
   if(msg.msg().header().code().class_() >= 0 && msg.msg().header().code().class_() <= 7){
     chr = msg.msg().header().code().class_() << 5;
   }else{
 	return 1;
   }
   if(msg.msg().header().code().detail() >= 0 && msg.msg().header().code().detail() <= 31){
     chr += msg.msg().header().code().detail();
   }else{
 	return 1;
   }
   stream.put_c(chr);
     //message ID
   if(msg.msg().header().message__id() >= 0 && msg.msg().header().message__id() <= 65535){
     encodeInteger(stream, msg.msg().header().message__id(), 2);
   }else{
 	return 1;
   }

   //TOKEN
   stream.put_os(msg.msg().token());

   //OPTIONS
   if(msg.msg().options().ispresent() && msg.msg().options()().size_of() > 0){
 	int optionOrder[msg.msg().options()().size_of()];
 	int temp;
 	for(int i = 0; i < msg.msg().options()().size_of(); i++){
 		optionOrder[i] = i;
 	}

 	//determine the order of options
 	for(int j = 0; j < msg.msg().options()().size_of()-1; j++){
       int minOptionCode = getOptionCode(msg.msg().options()()[optionOrder[j]]);
       int minOptionIndex = j;
       for(int i = j+1; i < msg.msg().options()().size_of(); i++){
         if(getOptionCode(msg.msg().options()()[optionOrder[i]]) < minOptionCode){
         	minOptionCode = getOptionCode(msg.msg().options()()[optionOrder[i]]);
         	minOptionIndex = i;
         }
       }
       temp = optionOrder[minOptionIndex];
       optionOrder[minOptionIndex] = optionOrder[j];
       optionOrder[j] = temp;
 	}

 	//encode options
 	int previousOptionCode = 0;
 	for(int i = 0; i < msg.msg().options()().size_of(); i++){
       int delta = getOptionCode(msg.msg().options()()[optionOrder[i]]) - previousOptionCode;
       int length = getOptionLength(msg.msg().options()()[optionOrder[i]]);

       previousOptionCode += delta;
       //first byte
       if(delta >= 0 && delta <= 12){
         chr = delta << 4;
       }else if(delta >= 13 && delta <= 268){
         chr = 13 << 4;
       }else if(delta >= 269 && delta <= 65535){
         chr = 14 << 4;
       }else{
     	return 1;
       }
       if(length >= 0 && length <= 12){
         chr += length;
 	  }else if(length >= 13 && length <= 268){
 	    chr += 13;
 	  }else if(length >= 269 && length <= 65535){
 	    chr += 14;
 	  }else{
 		return 1;
 	  }
       stream.put_c(chr);

       //optional delta
       if(delta >= 13 && delta <= 268){
         chr = delta - 13;
         stream.put_c(chr);
       }else if(delta >= 269 && delta <= 65535){
         chr = (delta - 269) >> 8;
         stream.put_c(chr);
         chr = (delta - 269) & 255;
         stream.put_c(chr);
       }
       //optional length
       if(length >= 13 && length <= 268){
         chr = length - 13;
         stream.put_c(chr);
       }else if(length >= 269 && length <= 65535){
         chr = (length - 269) >> 8;
         stream.put_c(chr);
         chr = (length - 269) & 255;
         stream.put_c(chr);
       }
       //option value
       if(length > 0){
     	switch(msg.msg().options()()[optionOrder[i]].get_selection()){
     	  case CoAP__Options::ALT_if__match:
     		  stream.put_os(msg.msg().options()()[optionOrder[i]].if__match());
     	    break;
     	  case CoAP__Options::ALT_uri__host:
     		  msg.msg().options()()[optionOrder[i]].uri__host().encode_utf8(stream, false);
     	    break;
 		  case CoAP__Options::ALT_etag:
 			  stream.put_os(msg.msg().options()()[optionOrder[i]].etag());
 			  break;
 		  case CoAP__Options::ALT_if__none__match:
 			  stream.put_os(msg.msg().options()()[optionOrder[i]].if__none__match());
 			  break;
 		  case CoAP__Options::ALT_observe:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].observe(), length);
 			  break;
 		  case CoAP__Options::ALT_uri__port:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].uri__port(), length);
 			  break;
 		  case CoAP__Options::ALT_location__path:
 			  msg.msg().options()()[optionOrder[i]].location__path().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_uri__path:
 			  msg.msg().options()()[optionOrder[i]].uri__path().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_content__format:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].content__format(), length);
 			  break;
 		  case CoAP__Options::ALT_max__age:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].max__age(), length);
 			  break;
 		  case CoAP__Options::ALT_uri__query:
 			  msg.msg().options()()[optionOrder[i]].uri__query().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_accept:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].accept(), length);
 			  break;
 		  case CoAP__Options::ALT_location__query:
 			  msg.msg().options()()[optionOrder[i]].location__query().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_block1:
 			  encodeBlock(stream, msg.msg().options()()[optionOrder[i]].block1(), length);
 			  break;
 		  case CoAP__Options::ALT_block2:
 			  encodeBlock(stream, msg.msg().options()()[optionOrder[i]].block2(), length);
 			  break;
 		  case CoAP__Options::ALT_proxy__uri:
 			  msg.msg().options()()[optionOrder[i]].proxy__uri().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_proxy__scheme:
 			  msg.msg().options()()[optionOrder[i]].proxy__scheme().encode_utf8(stream, false);
 			  break;
 		  case CoAP__Options::ALT_size1:
 			  encodeInteger(stream, msg.msg().options()()[optionOrder[i]].size1(), length);
 			  break;
 		  case CoAP__Options::ALT_unknown__option:
 			  stream.put_os(msg.msg().options()()[optionOrder[i]].unknown__option().option__value());
 			  break;
 		  case CoAP__Options::UNBOUND_VALUE:
 		  default:
 			return 8;
 			break;
 		}
       }
 	}
   }

   //PAYLOAD
   if(msg.msg().payload().ispresent()){
     stream.put_c(255); //payload marker
     stream.put_os(msg.msg().payload()());
   }

   TTCN_Logger::begin_event(TTCN_DEBUG);
   TTCN_Logger::log_event("Encoded CoAP message: ");
   stream.log();
   TTCN_Logger::end_event();

   stream.get_string(str);

   return 0;
 }

 //helper functions
 int getOptionCode(CoAP__Options option){
   switch(option.get_selection()){
     case CoAP__Options::ALT_if__match:
     	    return 1;
         break;
     case CoAP__Options::ALT_uri__host:
         	return 3;
         break;
     case CoAP__Options::ALT_etag:
         	return 4;
         break;
     case CoAP__Options::ALT_if__none__match:
         	return 5;
         break;
     case CoAP__Options::ALT_observe:
         	return 6;
         break;
     case CoAP__Options::ALT_uri__port:
         	return 7;
         break;
     case CoAP__Options::ALT_location__path:
         	return 8;
         break;
     case CoAP__Options::ALT_uri__path:
         	return 11;
         break;
     case CoAP__Options::ALT_content__format:
         	return 12;
         break;
     case CoAP__Options::ALT_max__age:
         	return 14;
         break;
     case CoAP__Options::ALT_uri__query:
         	return 15;
         break;
     case CoAP__Options::ALT_accept:
         	return 17;
         break;
     case CoAP__Options::ALT_location__query:
         	return 20;
         break;
     case CoAP__Options::ALT_block1: // RFC 7959
         	return 27;
         break;
     case CoAP__Options::ALT_block2: // RFC 7959
         	return 23;
         break;
     case CoAP__Options::ALT_proxy__uri:
         	return 35;
         break;
     case CoAP__Options::ALT_proxy__scheme:
         	return 39;
         break;
     case CoAP__Options::ALT_size1:
         	return 60;
         break;
     case CoAP__Options::ALT_unknown__option:
         	return option.unknown__option().option__code();
         break;
     case CoAP__Options::UNBOUND_VALUE:
     default:
     	TTCN_error("CoAP: Error at getOptionCode!");
     	break;
   }
 }

 int getOptionLength(CoAP__Options option){
   switch(option.get_selection()){
     case CoAP__Options::ALT_if__match:
     	    return option.if__match().lengthof();
         break;
     case CoAP__Options::ALT_uri__host:
         	return option.uri__host().lengthof();
         break;
     case CoAP__Options::ALT_etag:
         	return option.etag().lengthof();
         break;
     case CoAP__Options::ALT_if__none__match:
         	return option.if__none__match().lengthof();
         break;
     case CoAP__Options::ALT_observe:
             return getIntegerLength(option.observe().get_long_long_val(), 3);
         break;
     case CoAP__Options::ALT_uri__port:
             return getIntegerLength(option.uri__port().get_long_long_val(), 2);
         break;
     case CoAP__Options::ALT_location__path:
         	return option.location__path().lengthof();
         break;
     case CoAP__Options::ALT_uri__path:
         	return option.uri__path().lengthof();
         break;
     case CoAP__Options::ALT_content__format:
     	return getIntegerLength(option.content__format().get_long_long_val(), 2);
         break;
     case CoAP__Options::ALT_max__age:
     	return getIntegerLength(option.max__age().get_long_long_val(), 4);
         break;
     case CoAP__Options::ALT_uri__query:
         	return option.uri__query().lengthof();;
         break;
     case CoAP__Options::ALT_accept:
     	return getIntegerLength(option.accept().get_long_long_val(), 2);
         break;
     case CoAP__Options::ALT_location__query:
         	return option.location__query().lengthof();
         break;
     case CoAP__Options::ALT_block1:
             return getBlockLengthForNum(option.block1().num().get_long_long_val());
         break;
     case CoAP__Options::ALT_block2:
             return getBlockLengthForNum(option.block2().num().get_long_long_val());
         break;
     case CoAP__Options::ALT_proxy__uri:
         	return option.proxy__uri().lengthof();
         break;
     case CoAP__Options::ALT_proxy__scheme:
         	return option.proxy__scheme().lengthof();
         break;
     case CoAP__Options::ALT_size1:
     	return getIntegerLength(option.size1().get_long_long_val(), 4);
         break;
     case CoAP__Options::ALT_unknown__option:
         	return option.unknown__option().option__value().lengthof();
         break;
     case CoAP__Options::UNBOUND_VALUE:
     default:
     	TTCN_error("CoAP: Error at getOptionLength!");
     	break;
   }
 }

 int getIntegerLength(const long long int value, int mode){
 	if(value == 0){
 	  return 0;
 	}else if(value / 269 == 0){
 	  return 1;
 	}else if(value / 65805 == 0){
 	  return 2;
 	}else if(mode == 4 && value / 16777485 == 0){
       return 3;
 	}else if(mode == 4 && value / 4294967296 == 0){
 	  return 4;
 	}else{
 		TTCN_error("CoAP: Error at getIntegerLength!");
 	}
 }

 void encodeInteger(TTCN_Buffer &stream, const long long int option, const int length){
   unsigned char chr;

   for(int i = length-1; i > 0; i--){
 	  chr = (option >> (8 * i)) & 255;
 	  stream.put_c(chr);
   }
   chr = option & 255;
   stream.put_c(chr);
 }

 long long int decodeInteger(OCTETSTRING const &str, const int position, const int length){
   int value = 0;

   for(int i = 0; i < length; i++){
 	  value += (str[position+i].get_octet() << (8 * (length-i-1)));
   }
   return value;
 }

 // RFC 7959
 int getBlockLengthForNum(const long long int num) {
 	if (num < 0 || num > 1048575)
 		TTCN_error("CoAP: Error at getBlockLengthForNum: num must larger than 0 and smaller than 1048576!");

 	if (num <= 15) { // 2^4-1
 		return 1;
 	}
 	else if (num <= 1023) { // 2^10-1
 		return 2;
 	}
 	else if (num <= 1048575) { // 2^20-1
 		return 3;
 	}
 	return 0;
 }

 // RFC 7959
 void encodeBlock(TTCN_Buffer &stream, const BlockOption option, const int length) {

 	unsigned char chr;

 	long long int num_val = option.num().get_long_long_val();

 	char szx;
 	szx = option.szx().get_long_long_val() & 0x07; // szx_val & 00000111b

 	char m;
 	if ((bool) option.m())
 		m = 0x08; // 00001000b
 	else
 		m = 0x00; // 00000000b

 	char num;
 	for(int i = length-1; i > 0; i--){
 	  	  num = (num_val >> (8 * i - 4)) & 0xff;
 	  	  stream.put_c(num);
 	}
 	num = (num_val << 4) & 0xf0; // num_val & 11110000b

 	chr = num | m | szx;
 	stream.put_c(chr);
 }

 void decodeBlock(BlockOption& block, OCTETSTRING const &str, const int position, const int length) {

 	int num = 0;
 	for(int i = 0; i < length-1; i++) {
 	  num += (str[position+i].get_octet() << (8 * (length-i-1) - 4));
 	}
 	num += (str[position+length-1].get_octet() >> 4) & 0x0f;

 	int szx = 0;
 	szx = str[position+length-1].get_octet() & 0x07;

 	int m = 0;
 	m = str[position+length-1].get_octet() & 0x08;

 	block.num() = INTEGER(num);
 	block.szx() = INTEGER(szx);
 	block.m() = BOOLEAN(m > 0);
 }

 }
	/******************************************************************************
	* Copyright (c) 2016 Ericsson AB
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Mate Kovacs - initial implementation and initial documentation
	* Antal Wu-Hen Chang
	* Naum Spaseski
	******************************************************************************/
	//
	// File: CoAP_EncDec.cc
	// Rev: R1A
	// Prodnr: CNL 113 829

	#include "CoAP_Types.hh"

	namespace CoAP__Types {

	int getOptionCode(CoAP__Options option);
	int getOptionLength(CoAP__Options option);
	int getIntegerLength(const long long int value, int mode);
	void encodeInteger(TTCN_Buffer &stream, const long long int option, const int length);
	long long int decodeInteger(OCTETSTRING const &str, const int position, const int length);
	int getBlockLengthForNum(const long long int num);
	void encodeBlock(TTCN_Buffer &stream, const BlockOption option, const int length);
	void decodeBlock(BlockOption& block, OCTETSTRING const &str, const int position, const int length);

	INTEGER
	f__CoAP__dec(OCTETSTRING const &str, CoAP__Message &msg)
	{
	if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
	TTCN_Logger::begin_event(TTCN_DEBUG);
	TTCN_Logger::log_event("Decoding CoAP message: ");
	str.log();
	TTCN_Logger::end_event();
	}

	if(str.lengthof() >= 4){
	const unsigned char* str_ptr = (const unsigned char*) str;
	unsigned char chr;
	int position = 0;
	int token_length = 0;
	int actual_option_code = 0;
	int count_of_options = 0;
	bool payload_marker = false;

	//version, message type and token length
	chr = str_ptr[0];
	msg.msg().header().version() = chr >> 6;
	msg.msg().header().msg__type() = (chr >> 4) & 3;
	token_length = chr & 15;
	//code
	chr = str_ptr[1];
	msg.msg().header().code().class_() = (chr >> 5) & 7;
	msg.msg().header().code().detail() = chr & 31;
	//message ID
	msg.msg().header().message__id() = str_ptr[2] * 256 + str_ptr[3];

	if(str.lengthof() > 4 && msg.msg().header().code().class_() == 0 && msg.msg().header().code().detail() == 0){
	msg.raw__message() = str;
	return 1;
	}

	position = 4;
	//token
	if(token_length > 0){
	if(str.lengthof() >= position + token_length){
	msg.msg().token() = OCTETSTRING(token_length, &str_ptr[position]);
	position += token_length;
	}else{
	msg.raw__message() = str;
	return 1;
	}
	}else{
	msg.msg().token() = OCTETSTRING(0, 0);
	}

	//options
	msg.msg().options() = OMIT_VALUE;
	if(str.lengthof() > 4){
	while(!payload_marker && str.lengthof() > position){
	int delta = str_ptr[position] >> 4;
	int length = str_ptr[position] & 15;
	if(delta == 15 && length != 15){
	msg.raw__message() = str;
	return 1;
	}
	position++;
	if(delta == 15 && length == 15){
	payload_marker = true;
	}else{
	//optional delta
	if(delta == 13){
	delta = str_ptr[position] + 13;
	position++;
	}else if(delta == 14){
	delta = (str_ptr[position] << 8) + str_ptr[position+1] + 269;
	position += 2;
	}
	//optional length
	if(length == 13){
	length = str_ptr[position] + 13;
	position++;
	}else if(length == 14){
	length = (str_ptr[position] << 8) + str_ptr[position+1] + 269;
	position += 2;
	}else if(length == 15){
	msg.raw__message() = str;
	return 1;
	}

	//value
	actual_option_code += delta;
	switch(actual_option_code){
	case 1:
	msg.msg().options()()[count_of_options].if__match() = OCTETSTRING(length, &str_ptr[position]);
	break;
	case 3:
	msg.msg().options()()[count_of_options].uri__host().decode_utf8(length, &str_ptr[position]);
	break;
	case 4:
	msg.msg().options()()[count_of_options].etag() = OCTETSTRING(length, &str_ptr[position]);
	break;
	case 5:
	msg.msg().options()()[count_of_options].if__none__match() = OCTETSTRING(0, 0);
	break;
	case 6:
	msg.msg().options()()[count_of_options].observe().set_long_long_val(decodeInteger(str, position, length));
	break;
	case 7:
	msg.msg().options()()[count_of_options].uri__port().set_long_long_val(decodeInteger(str, position, length));
	break;
	case 8:
	msg.msg().options()()[count_of_options].location__path().decode_utf8(length, &str_ptr[position]);
	break;
	case 11:
	msg.msg().options()()[count_of_options].uri__path().decode_utf8(length, &str_ptr[position]);
	break;
	case 12:
	msg.msg().options()()[count_of_options].content__format().set_long_long_val(decodeInteger(str, position, length));
	break;
	case 14:
	msg.msg().options()()[count_of_options].max__age().set_long_long_val(decodeInteger(str, position, length));
	break;
	case 15:
	msg.msg().options()()[count_of_options].uri__query().decode_utf8(length, &str_ptr[position]);
	break;
	case 17:
	msg.msg().options()()[count_of_options].accept().set_long_long_val(decodeInteger(str, position, length));
	break;
	case 20:
	msg.msg().options()()[count_of_options].location__query().decode_utf8(length, &str_ptr[position]);
	break;
	case 23: // Block2 RFC 7959
	decodeBlock(msg.msg().options()()[count_of_options].block2(), str, position, length);
	break;
	case 27: // Block1 RFC 7959
	decodeBlock(msg.msg().options()()[count_of_options].block1(), str, position, length);
	break;
	case 35:
	msg.msg().options()()[count_of_options].proxy__uri().decode_utf8(length, &str_ptr[position]);
	break;
	case 39:
	msg.msg().options()()[count_of_options].proxy__scheme().decode_utf8(length, &str_ptr[position]);
	break;
	case 60:
	msg.msg().options()()[count_of_options].size1().set_long_long_val(decodeInteger(str, position, length));
	break;
	default:
	msg.msg().options()()[count_of_options].unknown__option().option__code() = actual_option_code;
	msg.msg().options()()[count_of_options].unknown__option().option__value() = OCTETSTRING(length, &str_ptr[position]);
	break;
	}
	position += length;
	count_of_options++;
	}
	}
	}

	//payload
	if(str.lengthof() > position){
	msg.msg().payload() = OCTETSTRING(str.lengthof() - position, &str_ptr[position]);
	if(msg.msg().payload()().lengthof() == 0){
	msg.raw__message() = str;
	return 1;
	}
	}else{
	if(payload_marker){
	msg.raw__message() = str;
	return 1;
	}else{
	msg.msg().payload() = OMIT_VALUE;
	}
	}
	}else{
	msg.raw__message() = str;
	return 1;
	}

	if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
	TTCN_Logger::begin_event(TTCN_DEBUG);
	TTCN_Logger::log_event("Decoded CoAP message: ");
	msg.log();
	TTCN_Logger::end_event();
	}

	return 0;
	}

	INTEGER
	f__CoAP__enc(CoAP__Message const &msg, OCTETSTRING &str)
	{
	TTCN_Buffer stream;
	unsigned char chr = 0;

	if(TTCN_Logger::log_this_event(TTCN_DEBUG)){
	TTCN_Logger::begin_event(TTCN_DEBUG);
	TTCN_Logger::log_event("Encoding CoAP message: ");
	msg.log();
	TTCN_Logger::end_event();
	}

	switch(msg.get_selection()){
	case CoAP__Message::ALT_raw__message:
	stream.put_os(msg.raw__message());
	stream.get_string(str);
	return 0;
	break;
	case CoAP__Message::ALT_msg:
	default:
	break;
	}

	//HEADER
	//version
	if(0 <= msg.msg().header().version() && msg.msg().header().version() <= 3){
	chr = msg.msg().header().version() << 6;
	}else{
	return 1;
	}
	//message type
	chr += msg.msg().header().msg__type() << 4;
	//tkl (token length)
	if(msg.msg().token().lengthof() >= 0 && msg.msg().token().lengthof() <= 8){
	chr += msg.msg().token().lengthof();
	}else{
	return 1;
	}
	stream.put_c(chr);
	//code
	if(msg.msg().header().code().class_() >= 0 && msg.msg().header().code().class_() <= 7){
	chr = msg.msg().header().code().class_() << 5;
	}else{
	return 1;
	}
	if(msg.msg().header().code().detail() >= 0 && msg.msg().header().code().detail() <= 31){
	chr += msg.msg().header().code().detail();
	}else{
	return 1;
	}
	stream.put_c(chr);
	//message ID
	if(msg.msg().header().message__id() >= 0 && msg.msg().header().message__id() <= 65535){
	encodeInteger(stream, msg.msg().header().message__id(), 2);
	}else{
	return 1;
	}

	//TOKEN
	stream.put_os(msg.msg().token());

	//OPTIONS
	if(msg.msg().options().ispresent() && msg.msg().options()().size_of() > 0){
	int optionOrder[msg.msg().options()().size_of()];
	int temp;
	for(int i = 0; i < msg.msg().options()().size_of(); i++){
	optionOrder[i] = i;
	}

	//determine the order of options
	for(int j = 0; j < msg.msg().options()().size_of()-1; j++){
	int minOptionCode = getOptionCode(msg.msg().options()()[optionOrder[j]]);
	int minOptionIndex = j;
	for(int i = j+1; i < msg.msg().options()().size_of(); i++){
	if(getOptionCode(msg.msg().options()()[optionOrder[i]]) < minOptionCode){
	minOptionCode = getOptionCode(msg.msg().options()()[optionOrder[i]]);
	minOptionIndex = i;
	}
	}
	temp = optionOrder[minOptionIndex];
	optionOrder[minOptionIndex] = optionOrder[j];
	optionOrder[j] = temp;
	}

	//encode options
	int previousOptionCode = 0;
	for(int i = 0; i < msg.msg().options()().size_of(); i++){
	int delta = getOptionCode(msg.msg().options()()[optionOrder[i]]) - previousOptionCode;
	int length = getOptionLength(msg.msg().options()()[optionOrder[i]]);

	previousOptionCode += delta;
	//first byte
	if(delta >= 0 && delta <= 12){
	chr = delta << 4;
	}else if(delta >= 13 && delta <= 268){
	chr = 13 << 4;
	}else if(delta >= 269 && delta <= 65535){
	chr = 14 << 4;
	}else{
	return 1;
	}
	if(length >= 0 && length <= 12){
	chr += length;
	}else if(length >= 13 && length <= 268){
	chr += 13;
	}else if(length >= 269 && length <= 65535){
	chr += 14;
	}else{
	return 1;
	}
	stream.put_c(chr);

	//optional delta
	if(delta >= 13 && delta <= 268){
	chr = delta - 13;
	stream.put_c(chr);
	}else if(delta >= 269 && delta <= 65535){
	chr = (delta - 269) >> 8;
	stream.put_c(chr);
	chr = (delta - 269) & 255;
	stream.put_c(chr);
	}
	//optional length
	if(length >= 13 && length <= 268){
	chr = length - 13;
	stream.put_c(chr);
	}else if(length >= 269 && length <= 65535){
	chr = (length - 269) >> 8;
	stream.put_c(chr);
	chr = (length - 269) & 255;
	stream.put_c(chr);
	}
	//option value
	if(length > 0){
	switch(msg.msg().options()()[optionOrder[i]].get_selection()){
	case CoAP__Options::ALT_if__match:
	stream.put_os(msg.msg().options()()[optionOrder[i]].if__match());
	break;
	case CoAP__Options::ALT_uri__host:
	msg.msg().options()()[optionOrder[i]].uri__host().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_etag:
	stream.put_os(msg.msg().options()()[optionOrder[i]].etag());
	break;
	case CoAP__Options::ALT_if__none__match:
	stream.put_os(msg.msg().options()()[optionOrder[i]].if__none__match());
	break;
	case CoAP__Options::ALT_observe:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].observe(), length);
	break;
	case CoAP__Options::ALT_uri__port:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].uri__port(), length);
	break;
	case CoAP__Options::ALT_location__path:
	msg.msg().options()()[optionOrder[i]].location__path().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_uri__path:
	msg.msg().options()()[optionOrder[i]].uri__path().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_content__format:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].content__format(), length);
	break;
	case CoAP__Options::ALT_max__age:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].max__age(), length);
	break;
	case CoAP__Options::ALT_uri__query:
	msg.msg().options()()[optionOrder[i]].uri__query().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_accept:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].accept(), length);
	break;
	case CoAP__Options::ALT_location__query:
	msg.msg().options()()[optionOrder[i]].location__query().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_block1:
	encodeBlock(stream, msg.msg().options()()[optionOrder[i]].block1(), length);
	break;
	case CoAP__Options::ALT_block2:
	encodeBlock(stream, msg.msg().options()()[optionOrder[i]].block2(), length);
	break;
	case CoAP__Options::ALT_proxy__uri:
	msg.msg().options()()[optionOrder[i]].proxy__uri().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_proxy__scheme:
	msg.msg().options()()[optionOrder[i]].proxy__scheme().encode_utf8(stream, false);
	break;
	case CoAP__Options::ALT_size1:
	encodeInteger(stream, msg.msg().options()()[optionOrder[i]].size1(), length);
	break;
	case CoAP__Options::ALT_unknown__option:
	stream.put_os(msg.msg().options()()[optionOrder[i]].unknown__option().option__value());
	break;
	case CoAP__Options::UNBOUND_VALUE:
	default:
	return 8;
	break;
	}
	}
	}
	}

	//PAYLOAD
	if(msg.msg().payload().ispresent()){
	stream.put_c(255); //payload marker
	stream.put_os(msg.msg().payload()());
	}

	TTCN_Logger::begin_event(TTCN_DEBUG);
	TTCN_Logger::log_event("Encoded CoAP message: ");
	stream.log();
	TTCN_Logger::end_event();

	stream.get_string(str);

	return 0;
	}

	//helper functions
	int getOptionCode(CoAP__Options option){
	switch(option.get_selection()){
	case CoAP__Options::ALT_if__match:
	return 1;
	break;
	case CoAP__Options::ALT_uri__host:
	return 3;
	break;
	case CoAP__Options::ALT_etag:
	return 4;
	break;
	case CoAP__Options::ALT_if__none__match:
	return 5;
	break;
	case CoAP__Options::ALT_observe:
	return 6;
	break;
	case CoAP__Options::ALT_uri__port:
	return 7;
	break;
	case CoAP__Options::ALT_location__path:
	return 8;
	break;
	case CoAP__Options::ALT_uri__path:
	return 11;
	break;
	case CoAP__Options::ALT_content__format:
	return 12;
	break;
	case CoAP__Options::ALT_max__age:
	return 14;
	break;
	case CoAP__Options::ALT_uri__query:
	return 15;
	break;
	case CoAP__Options::ALT_accept:
	return 17;
	break;
	case CoAP__Options::ALT_location__query:
	return 20;
	break;
	case CoAP__Options::ALT_block1: // RFC 7959
	return 27;
	break;
	case CoAP__Options::ALT_block2: // RFC 7959
	return 23;
	break;
	case CoAP__Options::ALT_proxy__uri:
	return 35;
	break;
	case CoAP__Options::ALT_proxy__scheme:
	return 39;
	break;
	case CoAP__Options::ALT_size1:
	return 60;
	break;
	case CoAP__Options::ALT_unknown__option:
	return option.unknown__option().option__code();
	break;
	case CoAP__Options::UNBOUND_VALUE:
	default:
	TTCN_error("CoAP: Error at getOptionCode!");
	break;
	}
	}

	int getOptionLength(CoAP__Options option){
	switch(option.get_selection()){
	case CoAP__Options::ALT_if__match:
	return option.if__match().lengthof();
	break;
	case CoAP__Options::ALT_uri__host:
	return option.uri__host().lengthof();
	break;
	case CoAP__Options::ALT_etag:
	return option.etag().lengthof();
	break;
	case CoAP__Options::ALT_if__none__match:
	return option.if__none__match().lengthof();
	break;
	case CoAP__Options::ALT_observe:
	return getIntegerLength(option.observe().get_long_long_val(), 3);
	break;
	case CoAP__Options::ALT_uri__port:
	return getIntegerLength(option.uri__port().get_long_long_val(), 2);
	break;
	case CoAP__Options::ALT_location__path:
	return option.location__path().lengthof();
	break;
	case CoAP__Options::ALT_uri__path:
	return option.uri__path().lengthof();
	break;
	case CoAP__Options::ALT_content__format:
	return getIntegerLength(option.content__format().get_long_long_val(), 2);
	break;
	case CoAP__Options::ALT_max__age:
	return getIntegerLength(option.max__age().get_long_long_val(), 4);
	break;
	case CoAP__Options::ALT_uri__query:
	return option.uri__query().lengthof();;
	break;
	case CoAP__Options::ALT_accept:
	return getIntegerLength(option.accept().get_long_long_val(), 2);
	break;
	case CoAP__Options::ALT_location__query:
	return option.location__query().lengthof();
	break;
	case CoAP__Options::ALT_block1:
	return getBlockLengthForNum(option.block1().num().get_long_long_val());
	break;
	case CoAP__Options::ALT_block2:
	return getBlockLengthForNum(option.block2().num().get_long_long_val());
	break;
	case CoAP__Options::ALT_proxy__uri:
	return option.proxy__uri().lengthof();
	break;
	case CoAP__Options::ALT_proxy__scheme:
	return option.proxy__scheme().lengthof();
	break;
	case CoAP__Options::ALT_size1:
	return getIntegerLength(option.size1().get_long_long_val(), 4);
	break;
	case CoAP__Options::ALT_unknown__option:
	return option.unknown__option().option__value().lengthof();
	break;
	case CoAP__Options::UNBOUND_VALUE:
	default:
	TTCN_error("CoAP: Error at getOptionLength!");
	break;
	}
	}

	int getIntegerLength(const long long int value, int mode){
	if(value == 0){
	return 0;
	}else if(value / 269 == 0){
	return 1;
	}else if(value / 65805 == 0){
	return 2;
	}else if(mode == 4 && value / 16777485 == 0){
	return 3;
	}else if(mode == 4 && value / 4294967296 == 0){
	return 4;
	}else{
	TTCN_error("CoAP: Error at getIntegerLength!");
	}
	}

	void encodeInteger(TTCN_Buffer &stream, const long long int option, const int length){
	unsigned char chr;

	for(int i = length-1; i > 0; i--){
	chr = (option >> (8 * i)) & 255;
	stream.put_c(chr);
	}
	chr = option & 255;
	stream.put_c(chr);
	}

	long long int decodeInteger(OCTETSTRING const &str, const int position, const int length){
	int value = 0;

	for(int i = 0; i < length; i++){
	value += (str[position+i].get_octet() << (8 * (length-i-1)));
	}
	return value;
	}

	// RFC 7959
	int getBlockLengthForNum(const long long int num) {
	if (num < 0 \|\| num > 1048575)
	TTCN_error("CoAP: Error at getBlockLengthForNum: num must larger than 0 and smaller than 1048576!");

	if (num <= 15) { // 2^4-1
	return 1;
	}
	else if (num <= 1023) { // 2^10-1
	return 2;
	}
	else if (num <= 1048575) { // 2^20-1
	return 3;
	}
	return 0;
	}

	// RFC 7959
	void encodeBlock(TTCN_Buffer &stream, const BlockOption option, const int length) {

	unsigned char chr;

	long long int num_val = option.num().get_long_long_val();

	char szx;
	szx = option.szx().get_long_long_val() & 0x07; // szx_val & 00000111b

	char m;
	if ((bool) option.m())
	m = 0x08; // 00001000b
	else
	m = 0x00; // 00000000b

	char num;
	for(int i = length-1; i > 0; i--){
	num = (num_val >> (8 * i - 4)) & 0xff;
	stream.put_c(num);
	}
	num = (num_val << 4) & 0xf0; // num_val & 11110000b

	chr = num \| m \| szx;
	stream.put_c(chr);
	}

	void decodeBlock(BlockOption& block, OCTETSTRING const &str, const int position, const int length) {

	int num = 0;
	for(int i = 0; i < length-1; i++) {
	num += (str[position+i].get_octet() << (8 * (length-i-1) - 4));
	}
	num += (str[position+length-1].get_octet() >> 4) & 0x0f;

	int szx = 0;
	szx = str[position+length-1].get_octet() & 0x07;

	int m = 0;
	m = str[position+length-1].get_octet() & 0x08;

	block.num() = INTEGER(num);
	block.szx() = INTEGER(szx);
	block.m() = BOOLEAN(m > 0);
	}

	}