/**************************************
 * RUN LENGTH ENCODER FOR ASCII TEXT  *        
 * Code Copyright 2000                *
 * Jonathan Sapan '03                 *
 * (unless noted otherwise)           *
 **************************************/
 
 /*See documentation for limitations and other information*/

#include <stdio.h>
#include <stdlib.h>
#define SENT_VAL 0


FILE *inputFile;
FILE *outputFile;

main(int argc, char *argv[])
{	
	int i, count, bytes_read;
	char a, A, current, last;
	char sentinel;
	
	inputFile  = fopen(argv[1], "rb");
	outputFile = fopen(argv[2], "w");
	
/*--------------------------------------------------------------------*/	
	if ( argc != 3 ) /*Check to see if program was called properly*/
	{
		fprintf(stdout, "TOO FEW ARGUMENTS\n" );
		exit(EXIT_SUCCESS);
	}
/*--------------------------------------------------------------------*/


/*--------------------------------------------------------------------*/	
	if ( (inputFile == NULL) || (outputFile == NULL) )
	{
		fprintf(stdout, "INVALID FILE SPECIFIED\n");
		exit(EXIT_SUCCESS);
	}
/*--------------------------------------------------------------------*/

/*Set value of sentinel byte*/
	sentinel = SENT_VAL;

	
/*Write sentinel to first byte in outputFile*/
	fprintf(outputFile , "%c", sentinel);
	

	fread( &last, 1, 1, inputFile );
	count = 1;
		
	while (1)
	{	
		bytes_read = fread( &current, 1, 1, inputFile );

		
		if ( count == 259 )
		{
			fprintf( outputFile, "%c%c%c", sentinel, last, (char)(count-4)  );
			
			if ( current == last )
				count = 0;
			else
				count = 1;
		}
		

			if ( current == last )
				count++;
				
			else	
			{	
				if ( count >= 4 )
					fprintf( outputFile, "%c%c%c", sentinel, last, (char)(count-4) );
	

					
				else
				{
					for (i = 0; i<count; i++)
						fprintf( outputFile, "%c", last );
				}
			
				count = 1;
			}
		
		
		
		
		if (bytes_read == 0 )
		{
			count--;
			
			if ( count >= 4 )
				fprintf( outputFile, "%c%c%c", sentinel, last, (char)(count-4) );

			else
			{
				for (i = 0; i<count; i++)
					fprintf( outputFile, "%c", last );
			}
			
			
			break;
		}
		
		last = current;	
	}	
	
	
	
	
			
	return 0;
}