1 files changed, 69 insertions, 0 deletions
diff --git a/base/src/main/java/bjc/utils/funcutils/NumberUtils.java b/base/src/main/java/bjc/utils/funcutils/NumberUtils.java
new file mode 100644
index 0000000..770d3a5
--- /dev/null
+++ b/base/src/main/java/bjc/utils/funcutils/NumberUtils.java
@@ -0,0 +1,69 @@
+package bjc.utils.funcutils;
+
+import java.util.function.Function;
+
+/**
+ * Utility functions for dealing with numbers
+ *
+ * @author ben
+ *
+ */
+public class NumberUtils {
+	/**
+	 * Compute the falling factorial of a number
+	 *
+	 * @param value
+	 *                The number to compute
+	 * @param power
+	 *                The power to do the falling factorial for
+	 * @return The falling factorial of the number to the power
+	 */
+	public static int fallingFactorial(final int value, final int power) {
+		if (power == 0)
+			return 1;
+		else if (power == 1)
+			return value;
+		else {
+			int result = 1;
+
+			for (int currentSub = 0; currentSub < power + 1; currentSub++) {
+				result *= value - currentSub;
+			}
+
+			return result;
+		}
+	}
+
+	/**
+	 * Evaluates a linear probability distribution
+	 *
+	 * @param winning
+	 *                The number of winning possibilities
+	 * @param total
+	 *                The number of total possibilities
+	 * @param rng
+	 *                The function to use to generate a random possibility
+	 * @return Whether or not a random possibility was a winning one
+	 */
+	public static boolean isProbable(final int winning, final int total, final Function<Integer, Integer> rng) {
+		return rng.apply(total) < winning;
+	}
+
+	/**
+	 * Check if a number is in an inclusive range.
+	 *
+	 * @param min
+	 *                The minimum value of the range.
+	 *
+	 * @param max
+	 *                The maximum value of the range.
+	 *
+	 * @param i
+	 *                The number to check.
+	 *
+	 * @return Whether the number is in the range.
+	 */
+	public static boolean between(final int min, final int max, final int i) {
+		return i >= min && i <= max;
+	}
+}