/*	Exercise 4.2.1:
Refine Exercise 4.1.5 by reading the original
bit sequence out of a user built file bit_seq.
Additionally, store the bit-stuffed bit sequence in the file
bit_stff (note that the integer values in the input and output stream
have to be separated by whitespaces).
Hint: The output file bit_stff
has to be declared as ofstream, which is defined like ifstream in
fstream.h.
*/

#include <list>
#include <fstream.h>
#include <stdlib.h> // atoi


using namespace std;

void main()
{
	list<int> l;
   char ch;
   int input=0;
   list<int>::iterator begin = l.begin();
   list<int>::iterator end = l.end();
   char* ifname ="c:\\data\\stlex\\bit_seq";

	// reading the original bit sequence out of a user built file bit_seq.
   cout<<"\nReading input file "<<ifname<<"...\n";
   ifstream fin;
   fin.open(ifname);
   if(!fin) return;

   while (!fin.eof())
   {
   	fin.get(ch);
      if(ch == '1') input =1;
      if(ch == '0') input =0;
      
   	if(input==1 || input==0)
   		l.push_back(input);
   	
   }
   l.pop_back();
   fin.close();

   // print values in list
   cout<<"Initial values are: ";
   begin = l.begin();
   end = l.end();
   while(begin!=end)
   {
   	cout<<*begin;
      begin++;
   }
   int unstuffed_sz= l.size();
   cout<<"\nunstuffed size: "<<unstuffed_sz;

   // bit stuffing algorithm
   begin = l.begin();
   end = l.end();

   int count_1 =0;
   while(end!=begin)
   {
   	if( *begin == 1 )
      	count_1++;

      if( *begin == 0 )
      	count_1 =0;

      if( count_1 ==6 )
      {
      	l.insert(begin,0);
         count_1 =1;
      }
      begin++;
   }

   // print bit stuffed list
   cout<<"\nStuffed list is\n";
   begin = l.begin();
   end = l.end();
   while(begin!=end)
   {
   	cout<<*begin;
      begin++;
   }

   // store the bit stuffed sequence in bit_stff
   begin = l.begin();
   end = l.end();
   char output;
   
   cout<<"\nWriting output file ...\n";
   ofstream fout;
   fout.open("c:\\data\\stlex\\bit_stff");

   while(begin!=end)
   {
      if ( *begin == 0 ) output ='0';
      if ( *begin == 1 ) output ='1'; 
   	fout.put(output);
      begin++;
   }
   fout.close();


   float absEx =(l.size() - unstuffed_sz);
   cout<<"\nAbsolute expansion is :"<<absEx;
   cout<<"\nRelative expansion is %"<<(absEx/unstuffed_sz)*100.00;


   // inverse algorithm
	list<int> inv;
   begin = l.begin();
   end = l.end();
   count_1=0;


   while(begin!=end)
   {
      if ( count_1 < 5 )
      {
      	if ( *begin == 1 ) count_1++;
			inv.push_back ( *begin );
      	begin++;
      }

      if ( count_1 == 5 )
      {
         	count_1 =0;
            ;
            if ( *(begin++) == 1 )		// plausibility test
            {
         	cerr<<"\nError, bits not stuffed correctly";
            exit(0);
            }
      }
	}


   // print inverted list
   cout<<"\ninverted list is\n";
   begin = inv.begin();
   end = inv.end();
   while(begin!=end)
   {
   	cout<<*begin;
      begin++;
   }

   inv.size() == unstuffed_sz ? cout<<"\ncorrect size" : cout<<"\nincorrect size";




   cin.ignore();
   cout<<"\nPress any key to exit";
   while(!cin.get())
   	;
}