/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (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.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.xerces.xni;

This class is used as a structure to pass text contained in the underlying
character buffer of the scanner. The offset and length fields allow the
buffer to be re-used without creating new character arrays.

Note: Methods that are passed an XMLString structure
should consider the contents read-only and not make any modifications
to the contents of the buffer. The method receiving this structure
should also not modify the offset and length if this structure (or
the values of this structure) are passed to another method.

Note: Methods that are passed an XMLString structure
are required to copy the information out of the buffer if it is to be
saved for use beyond the scope of the method. The contents of the 
structure are volatile and the contents of the character buffer cannot
be assured once the method that is passed this structure returns.
Therefore, methods passed this structure should not save any reference
to the structure or the character array contained in the structure.
Author:
Eric Ye, IBM, Andy Clark, IBM
Version:
$Id: XMLString.java 447247 2006-09-18 05:23:52Z mrglavas $/**
 * This class is used as a structure to pass text contained in the underlying
 * character buffer of the scanner. The offset and length fields allow the
 * buffer to be re-used without creating new character arrays.
 * <p>
 * <strong>Note:</strong> Methods that are passed an XMLString structure
 * should consider the contents read-only and not make any modifications
 * to the contents of the buffer. The method receiving this structure
 * should also not modify the offset and length if this structure (or
 * the values of this structure) are passed to another method.
 * <p>
 * <strong>Note:</strong> Methods that are passed an XMLString structure
 * are required to copy the information out of the buffer if it is to be
 * saved for use beyond the scope of the method. The contents of the 
 * structure are volatile and the contents of the character buffer cannot
 * be assured once the method that is passed this structure returns.
 * Therefore, methods passed this structure should not save any reference
 * to the structure or the character array contained in the structure.
 *
 * @author Eric Ye, IBM
 * @author Andy Clark, IBM
 *
 * @version $Id: XMLString.java 447247 2006-09-18 05:23:52Z mrglavas $
 */
public class XMLString {

    //
    // Data
    //

    
The character array. /** The character array. */
    public char[] ch;

    
The offset into the character array. /** The offset into the character array. */
    public int offset;

    
The length of characters from the offset. /** The length of characters from the offset. */
    public int length;

    //
    // Constructors
    //

    
Default constructor. /** Default constructor. */
    public XMLString() {
    } // <init>()

    
Constructs an XMLString structure preset with the specified
values.
Params:
ch –     The character array.
offset – The offset into the character array.
length – The length of characters from the offset./**
     * Constructs an XMLString structure preset with the specified
     * values.
     * 
     * @param ch     The character array.
     * @param offset The offset into the character array.
     * @param length The length of characters from the offset.
     */
    public XMLString(char[] ch, int offset, int length) {
        setValues(ch, offset, length);
    } // <init>(char[],int,int)

    
Constructs an XMLString structure with copies of the values in
the given structure.

Note: This does not copy the character array;
only the reference to the array is copied.
Params:
string – The XMLString to copy./**
     * Constructs an XMLString structure with copies of the values in
     * the given structure.
     * <p>
     * <strong>Note:</strong> This does not copy the character array;
     * only the reference to the array is copied.
     *
     * @param string The XMLString to copy.
     */
    public XMLString(XMLString string) {
        setValues(string);
    } // <init>(XMLString)

    //
    // Public methods
    //

    
Initializes the contents of the XMLString structure with the
specified values.
Params:
ch –     The character array.
offset – The offset into the character array.
length – The length of characters from the offset./**
     * Initializes the contents of the XMLString structure with the
     * specified values.
     * 
     * @param ch     The character array.
     * @param offset The offset into the character array.
     * @param length The length of characters from the offset.
     */
    public void setValues(char[] ch, int offset, int length) {
        this.ch = ch;
        this.offset = offset;
        this.length = length;
    } // setValues(char[],int,int)

    
Initializes the contents of the XMLString structure with copies
of the given string structure.

Note: This does not copy the character array;
only the reference to the array is copied.
Params:
s – /**
     * Initializes the contents of the XMLString structure with copies
     * of the given string structure.
     * <p>
     * <strong>Note:</strong> This does not copy the character array;
     * only the reference to the array is copied.
     * 
     * @param s
     */
    public void setValues(XMLString s) {
        setValues(s.ch, s.offset, s.length);
    } // setValues(XMLString)

    
Resets all of the values to their defaults. /** Resets all of the values to their defaults. */
    public void clear() {
        this.ch = null;
        this.offset = 0;
        this.length = -1;
    } // clear()

    
Returns true if the contents of this XMLString structure and
the specified array are equal.
Params:
ch –     The character array.
offset – The offset into the character array.
length – The length of characters from the offset./**
     * Returns true if the contents of this XMLString structure and
     * the specified array are equal.
     * 
     * @param ch     The character array.
     * @param offset The offset into the character array.
     * @param length The length of characters from the offset.
     */
    public boolean equals(char[] ch, int offset, int length) {
        if (ch == null) {
            return false;
        }
        if (this.length != length) {
            return false;
        }

        for (int i=0; i<length; i++) {
            if (this.ch[this.offset+i] != ch[offset+i] ) {
                return false;
            }
        }
        return true;
    } // equals(char[],int,int):boolean

    
Returns true if the contents of this XMLString structure and
the specified string are equal.
Params:
s – The string to compare./**
     * Returns true if the contents of this XMLString structure and
     * the specified string are equal.
     * 
     * @param s The string to compare.
     */
    public boolean equals(String s) {
        if (s == null) {
            return false;
        }
        if ( length != s.length() ) {
            return false;
        }

        // is this faster than call s.toCharArray first and compare the 
        // two arrays directly, which will possibly involve creating a
        // new char array object.
        for (int i=0; i<length; i++) {
            if (ch[offset+i] != s.charAt(i)) {
                return false;
            }
        }

        return true;
    } // equals(String):boolean

    //
    // Object methods
    //

    
Returns a string representation of this object. /** Returns a string representation of this object. */
    public String toString() {
        return length > 0 ? new String(ch, offset, length) : "";
    } // toString():String

} // class XMLString