/********************************
 * HUFFMAN ENCODER              *
 * Code Copyright 2000          *
 * Jonathan Sapan '03           *
 * (unless noted otherwise)     *
 ********************************/



#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <math.h>
#include "tree.h"

/*
	The following is in tree.h:
	#define CHARS
	#define BIT_BUFF_SIZE
	#define BYTE_BUFF_SIZE
	
	 			AND
	 			
	All function prototypes except 
	qsort(), which is from stdlib.h,
	and all type definitions.
*/


FILE *inputFile;
FILE *outputFile;

extern int bitBuffer[BIT_BUFF_SIZE];
extern unsigned char byteBuffer[BYTE_BUFF_SIZE];

extern int bit_num; 
extern int byte_num;

int main(int argc, char *argv[])
{
	int i, j, sum;
	unsigned char a, c, A;
	unsigned int x, B;
	letter char_array[CHARS];

/*--------------------------------------------------------------------*/	
	if ( argc != 3 ) /*Check to see if program was called properly*/
	{
		fprintf(stdout, "TOO FEW ARGUMENTS\n" );
		exit(EXIT_SUCCESS);
	}
/*--------------------------------------------------------------------*/
	
	for (i=0; i<BIT_BUFF_SIZE; i++)
		bitBuffer[i] = 0;
		
	for (i=0; i<BYTE_BUFF_SIZE; i++)
		byteBuffer[i] = 0;	
	
	for (i=0; i<CHARS; i++)
	{
		char_array[i].freq = 0;
		char_array[i].ascii = i;
	}
			
	inputFile  = fopen(argv[1], "rb");
	outputFile = fopen(argv[2], "wb");

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


	while (fread(&a, 1, 1, inputFile) == 1)
	  char_array[(int)a].freq++;
		
	rewind(inputFile);


/* QuickSort the array based on frequency */
qsort( char_array, CHARS, sizeof(letter),  compare );


/*Finds index of fist non-empty element*/
	
	for(i=0; char_array[i].freq == 0; i++)  
		;
	

/*--------------------------------------------------------*/
	/*Write frequency data to output so file can be decoded*/	

	for ( j = i; j<CHARS; j++ )
	{
		c = char_array[j].ascii;
		x = char_array[j].freq;
		
		fwrite( &c, 1, 1, outputFile );
		fwrite( &x, sizeof(unsigned int), 1, outputFile );
	}
	
/*--------------------------------------------------------*/	



/*--------------------------------------------------------*/	
	/*Write empty blocks to signal table termination*/
		A = 0;
		B = 0;
		fwrite( &A, 1, 1, outputFile );
		fwrite( &B, sizeof(unsigned int), 1, outputFile );
/*--------------------------------------------------------*/	
	
				
	for(i = i; i < CHARS; i++)
		InsertNode( NewNode( char_array[i] ) );
		
			
/*	

	Call to Display() outputs frequency table	
*/	
	Display();
	
	merge();

	traverse();
	
	
	
	while (fread(&a, 1, 1, inputFile) == 1)
           CodeIO(a);
           


/*--------------------CLEAR BUFFERS------------------*/	
	if ( byte_num > 0 )
	{
		fwrite(byteBuffer, 1, byte_num, outputFile);
		byte_num = 0;
	}
	
	
	if ( bit_num > 0 )
	{
		
		for ( j = bit_num; j < BIT_BUFF_SIZE; j++)
			bitBuffer[j] = 0;
				
		for ( j = 0, sum = 0; j < BIT_BUFF_SIZE; j++ )
			sum += bitBuffer[j] * pow(2, (BIT_BUFF_SIZE - 1 - j) );
		
		byteBuffer[0] = sum;
		fwrite(&byteBuffer[0], 1, 1, outputFile);

	}
	
 
	
/*--------------------CLEAR BUFFERS------------------*/	


	
	fclose(inputFile);
	fclose(outputFile);
	
	return 0;
}