using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WPM.Poly2Tri {
	public class MathUtil {
		public static double EPSILON = 1e-12;

		public static bool AreValuesEqual (double val1, double val2) {
			return AreValuesEqual (val1, val2, EPSILON);
		}

		public static bool AreValuesEqual (double val1, double val2, double tolerance) {
			if (val1 >= (val2 - tolerance) && val1 <= (val2 + tolerance)) {
				return true;
			}

			return false;
		}

		public static bool IsValueBetween (double val, double min, double max, double tolerance) {
			if (min > max) {
				double tmp = min;
				min = max;
				max = tmp;
			}
			if ((val + tolerance) >= min && (val - tolerance) <= max) {
				return true;
			}

			return false;
		}

		public static double RoundWithPrecision (double f, double precision) {
			if (precision < 0.0) {
				return f;
			}

			double mul = Math.Pow (10.0, precision);
			double fTemp = Math.Floor (f * mul) / mul;

			return fTemp;
		}

		public static double Clamp (double a, double low, double high) {
			return Math.Max (low, Math.Min (a, high));
		}

		public static void Swap<T> (ref T a, ref T b) {
			T tmp = a;
			a = b;
			b = tmp;
		}

		public static uint Jenkins32Hash (byte[] data, uint nInitialValue) {
			foreach (byte b in data) {
				nInitialValue += (uint)b;
				nInitialValue += (nInitialValue << 10);
				nInitialValue += (nInitialValue >> 6);
			}

			nInitialValue += (nInitialValue << 3);
			nInitialValue ^= (nInitialValue >> 11);
			nInitialValue += (nInitialValue << 15);

			return nInitialValue;
		}
	}
}