#include <stdio.h>
#include "numbers.h"



/* Reads a number with up to SIZE many digits.
 * Stores the number modulo 2*10^{SIZE} with least
 * significant digit first. Returns error if number
 * has more than SIZE digits.
 */
int read_number(Number number)
{
	char symbol; /* Stores current input symbol */
	Number temp; /* temporary storage for numbers */
	int size; /* stores the number of digits in input */

	temp = allocate_space();

	symbol = skip_blanks(); /* Read the first non-white space symbol */
	if (symbol == '-') { /* negative number */
		number[SIZE] = 1;
		symbol = getchar(); /* read the first digit */
	}
	else /* positive number */
		number[SIZE] = 0;

	for (size = 0; 1; size++) {
		if ((symbol < '0') || (symbol > '9')) /* not a digit */
			break;
		if (size == SIZE) { /* input too large */
			printf("Input too large: number should be at most %d digits\n", SIZE);
			return 0;
		}
		temp[size] = symbol - '0';
		symbol = getchar(); /* read next symbol */
	}

	/* Store number in reverse order ,leaving the sign in place */
	int i;

	for (i = 0; i < size; i++)
		number[i] = temp[size-1-i];
	for (i = size; i < SIZE; i++)
		number[i] = 0;
	
	/* Convert to modular representation */
	number2modular(number);

	free_space(temp);

	return 1;
} /* end of read_number() */


/* Output the given number. It first converts the number
 * from its representation modulo 2*10^{SIZE} to normal.
 */

void output_number(Number number)
{
	int i;
	Number temp;

	temp = allocate_space();

	/* Transfer the number to temp */
	copy_number(temp, number);

	/* Convert it to normal representation */
	number2modular(temp);

	/* Skip the leading zeroes */
	for (i = SIZE-1; i >= 0; i--)
		if (temp[i] > 0)
			break;
	
	if (i == -1) { /* the sum is zero! */
		printf("0\n");
		return;
	}

	if (temp[SIZE] == 1) /* negative number */
		putchar('-');

	for (; i >= 0; i--)
		putchar(temp[i]+'0');
	printf("\n");

	free_space(temp);
}


/* Skips white spaces in the input and returns the first
 * non-white space symbol. The white spaces are defined to
 * be BLANK, NEW LINE, and TAB symbols.
 */
char skip_blanks()
{
	char c;

	c = getchar();

	for (; (c == ' ') || (c == '\n') || (c == '\t'); )
		c = getchar();
	
	return c;
}


/* Set the number to the value n */
void set_number(Number number, int n)
{
	int i;

	if (n < 0) { // negative number
		n = -n; // make it positive
		number[SIZE] = 1; // Set the sign of number to negative
	}
	else // n is positive
		number[SIZE] = 0;  // set the sign of number to positive

	for (i = 0; i < SIZE; i++) {
		number[i] = n % 10; // store the last digit of n
		n = n / 10; // remove the last digit of n
	}

	// Now change the number to modular representation
	number2modular(number);
}


/* Copies the number num2 to num1 */
void copy_number(Number num1, Number num2)
{
	for (int i = 0; i <= SIZE; i++)
		num1[i] = num2[i];
}