Release v0.2.0v0.2.0

1 files changed, 114 insertions, 0 deletions

diff --git a/src/org/unitConverter/math/DecimalComparison.java b/src/org/unitConverter/math/DecimalComparison.java
new file mode 100644
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+++ b/src/org/unitConverter/math/DecimalComparison.java
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+/**
+ * Copyright (C) 2019 Adrien Hopkins
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.unitConverter.math;
+
+/**
+ * A class that contains methods to compare float and double values.
+ * 
+ * @author Adrien Hopkins
+ * @since 2019-03-18
+ * @since v0.2.0
+ */
+public final class DecimalComparison {
+	/**
+	 * The value used for double comparison. If two double values are within this value multiplied by the larger value,
+	 * they are considered equal.
+	 * 
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final double DOUBLE_EPSILON = 1.0e-15;
+
+	/**
+	 * The value used for float comparison. If two float values are within this value multiplied by the larger value,
+	 * they are considered equal.
+	 * 
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final float FLOAT_EPSILON = 1.0e-6f;
+
+	/**
+	 * Tests for equality of double values using {@link #DOUBLE_EPSILON}.
+	 * 
+	 * @param a
+	 *            first value to test
+	 * @param b
+	 *            second value to test
+	 * @return whether they are equal
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final boolean equals(final double a, final double b) {
+		return DecimalComparison.equals(a, b, DOUBLE_EPSILON);
+	}
+
+	/**
+	 * Tests for double equality using a custom epsilon value.
+	 * 
+	 * @param a
+	 *            first value to test
+	 * @param b
+	 *            second value to test
+	 * @param epsilon
+	 *            allowed difference
+	 * @return whether they are equal
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final boolean equals(final double a, final double b, final double epsilon) {
+		return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
+	}
+
+	/**
+	 * Tests for equality of float values using {@link #FLOAT_EPSILON}.
+	 * 
+	 * @param a
+	 *            first value to test
+	 * @param b
+	 *            second value to test
+	 * @return whether they are equal
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final boolean equals(final float a, final float b) {
+		return DecimalComparison.equals(a, b, FLOAT_EPSILON);
+	}
+
+	/**
+	 * Tests for float equality using a custom epsilon value.
+	 * 
+	 * @param a
+	 *            first value to test
+	 * @param b
+	 *            second value to test
+	 * @param epsilon
+	 *            allowed difference
+	 * @return whether they are equal
+	 * @since 2019-03-18
+	 * @since v0.2.0
+	 */
+	public static final boolean equals(final float a, final float b, final float epsilon) {
+		return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
+	}
+
+	// You may NOT get any DecimalComparison instances
+	private DecimalComparison() {
+		throw new AssertionError();
+	}
+
+}