kge/Cursor.cc

///
/// \file Cursor.cc
/// \author kyle 
/// \created 10/11/23
/// \brief
///
/// \section COPYRIGHT
/// Copyright 2023 K. Isom <kyle@imap.cc>
///
/// Permission to use, copy, modify, and/or distribute this software for
/// any purpose with or without fee is hereby granted, provided that the
/// above copyright notice and this permission notice appear in all copies.
///
/// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
/// WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
/// WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
/// BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
/// OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
/// WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
/// ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
/// SOFTWARE.
///

#include "Cursor.h"
#include "Defs.h"


/// \todo kyle Can cursors be replaced with std::pair?


static std::pair<size_t, size_t>
orderedPair(size_t a, size_t b)
{
	if (a > b) {
		return {b, a};
	}

	return {a, b};
}


static size_t
isqrt(size_t n)
{
	if (n < 2) {
		return n;
	}

	size_t	start = 0;
	size_t	end = n / 2;
	size_t	result = 0;

	while (start <= end) {
		auto middle = (start + end) >> 1;
		result = middle * middle;
		if (result == n) {
			return middle;
		}

		if (result < n) {
			start = middle + 1;
			result = middle;
		} else {
			end = middle - 1;
			result = middle;
		}
	}

	return result;
}


Cursor Cursor::Update(const Cursor &c)
{
	Cursor prev(this->x, this->y);
	this->X(c.X());
	this->Y(c.Y());
	return prev;
}


size_t Cursor::Distance(const Cursor &c) const
{
	auto xPair = orderedPair(this->x, c.X());
	auto yPair = orderedPair(this->y, c.Y());

	auto x0 = xPair.second - xPair.first;
	x0 *= x0;

	auto y0 = yPair.second - xPair.first;
	y0 *= y0;

	auto dist = x0 + y0;
	return isqrt(dist);
}


std::ostream &operator<<(std::ostream &os, const Cursor &cursor)
{
	os << cursor.X() << "," << cursor.Y();
	return os;
}