SourcePosition.java

/***** BEGIN LICENSE BLOCK *****
 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/cpl-v10.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
 * Copyright (C) 2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
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 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the CPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/
package org.jruby.lexer.yacc;

import java.io.Serializable;

/**
 * 
 * Position within a source. This could have column as well, but it currently
 * does not. A normal ruby intrepretter does not use this information in
 * error/warning information. An IDE using this may need it though. This is
 * trivially added if need be.
 * 
 * @see org.jruby.lexer.yacc.ISourcePosition
 */
public class SourcePosition implements ISourcePosition, Serializable {
	private static final long serialVersionUID = 3762529027281400377L;

	// The start/end offsets of the source
	private int startOffset;
	private final int endOffset;

	/**
	 * Creates a default source position - required for serialization.
	 */
	public SourcePosition() {
		this(0, 0);
	}

	/**
	 * Creates a new source position.
	 * 
	 * @param file
	 *            location of the source (must not be null)
	 * @param line
	 *            what line within the source
	 * @deprecated
	 */
	public SourcePosition(String file, int startOffset, int endOffset) {
		this(startOffset, endOffset);
	}

	public SourcePosition(int startOffset, int endOffset) {
		this.startOffset = startOffset;
		this.endOffset = endOffset;
	}

	/**
	 * @see org.jruby.lexer.yacc.ISourcePosition#getFile()
	 * @deprecated
	 */
	public String getFile() {
		return "";
	}

	/**
	 * @param object
	 *            the object which should be compared
	 * @return simple Object.equals() implementation
	 */
	public boolean equals(Object object) {
		if (object == this) {
			return true;
		}
		if (!(object instanceof SourcePosition)) {
			return false;
		}
		final SourcePosition other = (SourcePosition) object;
		return startOffset == other.startOffset && endOffset == other.endOffset;
	}

	/**
	 * Something we can use for identity in hashing, etc...
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode() {
		return startOffset ^ endOffset;
	}

	/**
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return "[" + startOffset + "..." + endOffset + ']';
	}

	/**
	 * @see org.jruby.lexer.yacc.ISourcePosition#adjustStartOffset(int)
	 */
	public void adjustStartOffset(int relativeValue) {
		startOffset += relativeValue;
		if (startOffset < 0)
			startOffset = 0;
	}

	/**
	 * Not used in interpreter
	 * 
	 * @see org.jruby.lexer.yacc.ISourcePosition#getStartOffset()
	 */
	public int getStartOffset() {
		return startOffset;
	}

	/**
	 * Not used in interpreter
	 * 
	 * @see org.jruby.lexer.yacc.ISourcePosition#getEndOffset()
	 */
	public int getEndOffset() {
		return endOffset;
	}

	/**
	 * @see org.jruby.lexer.yacc.ISourcePosition#union(ISourcePosition)
	 */
	public ISourcePosition union(ISourcePosition other) {
		// Enebo: All AST nodes but IterNode are in ascending order
		// position-wise. We should not
		// need to safe-guard that other is a smaller source position
		return new SourcePosition(startOffset, other.getEndOffset());
	}

	/**
	 * Not used in interpreter Creates a new position the encloses both
	 * parameter positions.
	 * 
	 * @param the
	 *            positions providing the boundaries for the new position.
	 */
	public static SourcePosition combinePosition(ISourcePosition firstPos,
			ISourcePosition secondPos) {
		int startOffset = firstPos.getStartOffset();
		int endOffset = firstPos.getEndOffset();

		if (startOffset > secondPos.getStartOffset()) {
			startOffset = secondPos.getStartOffset();
		}

		if (endOffset < secondPos.getEndOffset()) {
			endOffset = secondPos.getEndOffset();
		}

		SourcePosition combinedPosition = new SourcePosition(startOffset,
				endOffset);

		return combinedPosition;
	}
}