1 files changed, 113 insertions, 0 deletions
diff --git a/org.eclipse.vex.core/src/org/eclipse/wst/xml/vex/core/internal/core/IntRange.java b/org.eclipse.vex.core/src/org/eclipse/wst/xml/vex/core/internal/core/IntRange.java
new file mode 100644
index 00000000..c680f169
--- /dev/null
+++ b/org.eclipse.vex.core/src/org/eclipse/wst/xml/vex/core/internal/core/IntRange.java
@@ -0,0 +1,113 @@
+/*******************************************************************************
+ * Copyright (c) 2004, 2008 John Krasnay and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *     John Krasnay - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.wst.xml.vex.core.internal.core;
+
+/**
+ * Represents a range of integers. Zero-length ranges (i.e. ranges where start
+ * == end) are permitted. This class is immutable.
+ */
+public class IntRange {
+
+	/**
+	 * Class constuctor.
+	 * 
+	 * @param start
+	 *            Start of the range.
+	 * @param end
+	 *            End of the range. Must be >= start.
+	 */
+	public IntRange(int start, int end) {
+		if (start > end) {
+			throw new IllegalArgumentException("start (" + start
+					+ ") is greater than end (" + end + ")");
+		}
+		this.start = start;
+		this.end = end;
+	}
+
+	/**
+	 * Returns the start of the range.
+	 */
+	public int getStart() {
+		return this.start;
+	}
+
+	/**
+	 * Returns the end of the range.
+	 */
+	public int getEnd() {
+		return this.end;
+	}
+
+	/**
+	 * Returns the range that represents the intersection of this range and the
+	 * given range. If the ranges do not intersect, returns null. May return an
+	 * empty range.
+	 * 
+	 * @param range
+	 *            Range with which to perform an intersection.
+	 */
+	public IntRange intersection(IntRange range) {
+		if (this.intersects(range)) {
+			return new IntRange(Math.max(this.start, range.start), Math.min(
+					this.end, range.end));
+		} else {
+			return null;
+		}
+
+	}
+
+	/**
+	 * Returns true if this range intersects the given range, even if the result
+	 * would be an empty range.
+	 * 
+	 * @param range
+	 *            Range with which to intersect.
+	 */
+	public boolean intersects(IntRange range) {
+		return this.start <= range.end && this.end >= range.start;
+	}
+
+	/**
+	 * Returns true if start and end are equal.
+	 */
+	public boolean isEmpty() {
+		return start == end;
+	}
+
+	/**
+	 * Returns a range that is the union of this range and the given range. If
+	 * the ranges are disjoint, the gap between the ranges is included in the
+	 * result.
+	 * 
+	 * @param range
+	 *            Rnage with which to perform the union
+	 */
+	public IntRange union(IntRange range) {
+		return new IntRange(Math.min(this.start, range.start), Math.min(
+				this.end, range.end));
+	}
+
+	public String toString() {
+		StringBuffer sb = new StringBuffer();
+		sb.append("IntRange(");
+		sb.append(start);
+		sb.append(",");
+		sb.append(end);
+		sb.append(")");
+		return sb.toString();
+	}
+
+	// ============================================================= PRIVATE
+
+	private int start;
+	private int end;
+}