#include <stdio.h>
#include <stdlib.h>

enum
{
	ERROR = -1,
	SUCCESS = 0,
	ASCII_Line_feed = 10,
	ASCII_Carriage_return = 13,
	ASCII_Record_Separator = 30,
	MAX_LINE_SIZE = 43162 //fails but 43161 works just fine ???
};

struct _node
{
	int value;
	struct _node *next;
};

typedef struct _node node;



int main(int argc, char *argv[])
{

	int c;

	int count;
	node *list = (node *)malloc(sizeof(node));
	list->next = NULL;
	list = NULL;
	
	FILE *fin; /* input file */
	FILE *fout; /* output file */

	/* write a single character to the output file */

	void write_text(node *line)
	{
		fputc (line->value, fout);
	
		/* Deal with case of not end of line */
		
		if(line->next != NULL)
		{
			write_text(line->next);
			line->next = NULL;
		}
		
		/* free allocated space that is no longer being used */
		
		//free(line);
		line = NULL;
		return;
	}
	
	/* Write entire line to file */

	void write_line()
	{
		/* Start line with the length of the line */
		
		fputc (count / 256, fout);
		fputc (count % 256, fout);
		count = 0;
		
		/* Deal with case of line without any text */
		
		if(list != NULL)
		{
			write_text(list);
		}
		
		/* Append end of line characters */
		
		fputc (ASCII_Carriage_return, fout);
		fputc (ASCII_Line_feed, fout);
		list = NULL;
		return;
	}
	
	/* add character to line or in the event that the line has reached maxed size write line */

	void add_node(node *a)
	{
		/* max line size check and correction */

		if(count == MAX_LINE_SIZE)
		{
			write_line();
		}
		
		/* deal with case of first character on line */
		
		if(a == NULL)
		{
			list = (node *)malloc(sizeof(node));
			list->value = c;
			list->next = NULL;
			return;
		}
		
		/* deal with inserting next character on line */
		
		if(a->next == NULL)
		{
			node *b = (node *)malloc(sizeof(node));
			a->next = b;
			b->value = c;
			b->next = NULL;
			return;
		}
		
		/* Walks down the line until the next character is a NULL */
		
		add_node(a->next);
		return;
	}


	/* only allow a correct number of inputs */

	if(argc != 3)
	{
		printf("ERROR: improper input, please format as : \ntxt2text input_file_name output_file_name");
		return ERROR;
	}

	/* open input file */

	fin = fopen(argv[1], "r");
	if (fin==NULL)
	{           
		printf("\nUnable to open file: %s!\n", argv[1]);
		return ERROR;
	}
	
	/* open output file */
	fout = fopen(argv[2], "w");
	if (fout==NULL)
	{
		printf("\nUnable to open output file: %s!\n", argv[2]);
		return ERROR;
	}
	
	/* Initialize local variables */
	
	count = 0;

	/* main loop */

	do 
	{
		c = getc(fin);
		
		switch (c)
		{
			case ASCII_Line_feed :
			{
				c = getc(fin);
				if (c != ASCII_Carriage_return)
				{
					ungetc(c, fin);
				}
			}
			case ASCII_Carriage_return :
			{
				c = getc(fin);
				if (c != ASCII_Line_feed)
				{
					ungetc(c, fin);
				}
			}
			case ASCII_Record_Separator : 
			case EOF : write_line(); break;
			default : count = count + 1; add_node(list);
		}

	}while (c != EOF);
	
	/* close input file */
	
	fclose(fin);
	
	/* close output file */
	
	fclose(fout);
	
	/* sinal success and terminate */
	
	return SUCCESS;
}