/*******************************************************************************
* Copyright (c) 2000, 2008 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.text;
import org.eclipse.core.runtime.Assert;
/**
* Positions describe text ranges of a document. Positions are adapted to
* changes applied to that document. The text range is specified by an offset
* and a length. Positions can be marked as deleted. Deleted positions are
* considered to no longer represent a valid text range in the managing
* document.
* <p>
* Positions attached to documents are usually updated by position updaters.
* Because position updaters are freely definable and because of the frequency
* in which they are used, the fields of a position are made publicly
* accessible. Clients other than position updaters are not allowed to access
* these public fields.
* </p>
* <p>
* Positions cannot be used as keys in hash tables as they override
* <code>equals</code> and <code>hashCode</code> as they would be value
* objects.
* </p>
*
* @see org.eclipse.jface.text.IDocument
*/
public class Position {
/** The offset of the position */
public int offset;
/** The length of the position */
public int length;
/** Indicates whether the position has been deleted */
public boolean isDeleted;
/**
* Creates a new position with the given offset and length 0.
*
* @param offset the position offset, must be >= 0
*/
public Position(int offset) {
this(offset, 0);
}
/**
* Creates a new position with the given offset and length.
*
* @param offset the position offset, must be >= 0
* @param length the position length, must be >= 0
*/
public Position(int offset, int length) {
Assert.isTrue(offset >= 0);
Assert.isTrue(length >= 0);
this.offset= offset;
this.length= length;
}
/**
* Creates a new, not initialized position.
*/
protected Position() {
}
/*
* @see java.lang.Object#hashCode()
*/
public int hashCode() {
int deleted= isDeleted ? 0 : 1;
return (offset << 24) | (length << 16) | deleted;
}
/**
* Marks this position as deleted.
*/
public void delete() {
isDeleted= true;
}
/**
* Marks this position as not deleted.
*
* @since 2.0
*/
public void undelete() {
isDeleted= false;
}
/*
* @see java.lang.Object#equals(java.lang.Object)
*/
public boolean equals(Object other) {
if (other instanceof Position) {
Position rp= (Position) other;
return (rp.offset == offset) && (rp.length == length);
}
return super.equals(other);
}
/**
* Returns the length of this position.
*
* @return the length of this position
*/
public int getLength() {
return length;
}
/**
* Returns the offset of this position.
*
* @return the offset of this position
*/
public int getOffset() {
return offset;
}
/**
* Checks whether the given index is inside
* of this position's text range.
*
* @param index the index to check
* @return <code>true</code> if <code>index</code> is inside of this position
*/
public boolean includes(int index) {
if (isDeleted)
return false;
return (this.offset <= index) && (index < this.offset + length);
}
/**
* Checks whether the intersection of the given text range
* and the text range represented by this position is empty
* or not.
*
* @param rangeOffset the offset of the range to check
* @param rangeLength the length of the range to check
* @return <code>true</code> if intersection is not empty
*/
public boolean overlapsWith(int rangeOffset, int rangeLength) {
if (isDeleted)
return false;
int end= rangeOffset + rangeLength;
int thisEnd= this.offset + this.length;
if (rangeLength > 0) {
if (this.length > 0)
return this.offset < end && rangeOffset < thisEnd;
return rangeOffset <= this.offset && this.offset < end;
}
if (this.length > 0)
return this.offset <= rangeOffset && rangeOffset < thisEnd;
return this.offset == rangeOffset;
}
/**
* Returns whether this position has been deleted or not.
*
* @return <code>true</code> if position has been deleted
*/
public boolean isDeleted() {
return isDeleted;
}
/**
* Changes the length of this position to the given length.
*
* @param length the new length of this position
*/
public void setLength(int length) {
Assert.isTrue(length >= 0);
this.length= length;
}
/**
* Changes the offset of this position to the given offset.
*
* @param offset the new offset of this position
*/
public void setOffset(int offset) {
Assert.isTrue(offset >= 0);
this.offset= offset;
}
/*
* @see java.lang.Object#toString()
* @since 3.5
*/
public String toString() {
String position= "offset: " + offset + ", length: " + length; //$NON-NLS-1$//$NON-NLS-2$
return isDeleted ? position + " (deleted)" : position; //$NON-NLS-1$
}
}
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