Eigenmath-fx/mcmp.cpp

// Bignum compare
//
//	returns
//
//	-1		a < b
//
//	0		a = b
//
//	1		a > b

#include "stdafx.h"
#include "defs.h"

int
mcmp(unsigned int *a, unsigned int *b)
{
	int i;

	if (MSIGN(a) == -1 && MSIGN(b) == 1)
		return -1;

	if (MSIGN(a) == 1 && MSIGN(b) == -1)
		return 1;

	// same sign

	if (MLENGTH(a) < MLENGTH(b)) {
		if (MSIGN(a) == 1)
			return -1;
		else
			return 1;
	}

	if (MLENGTH(a) > MLENGTH(b)) {
		if (MSIGN(a) == 1)
			return 1;
		else
			return -1;
	}

	// same length

	for (i = MLENGTH(a) - 1; i > 0; i--)
		if (a[i] != b[i])
			break;

	if (a[i] < b[i]) {
		if (MSIGN(a) == 1)
			return -1;
		else
			return 1;
	}

	if (a[i] > b[i]) {
		if (MSIGN(a) == 1)
			return 1;
		else
			return -1;
	}

	return 0;
}

int
mcmpint(unsigned int *a, int n)
{
	int t;
	unsigned int *b;
	b = mint(n);
	t = mcmp(a, b);
	mfree(b);
	return t;
}