/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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 com.sun.org.apache.xerces.internal.util;

import com.sun.org.apache.xerces.internal.xni.XMLString;

/**

 * XMLString is a structure used to pass character arrays. However,

 * XMLStringBuffer is a buffer in which characters can be appended

 * and extends XMLString so that it can be passed to methods

 * expecting an XMLString object. This is a safe operation because

 * it is assumed that any callee will <strong>not</strong> modify

 * the contents of the XMLString structure.

 * <p>

 * The contents of the string are managed by the string buffer. As

 * characters are appended, the string buffer will grow as needed.

 * <p>

 * <strong>Note:</strong> Never set the <code>ch</code>,

 * <code>offset</code>, and <code>length</code> fields directly.

 * These fields are managed by the string buffer. In order to reset

 * the buffer, call <code>clear()</code>.

 *

 * @author Andy Clark, IBM

 * @author Eric Ye, IBM

 *

 */

public class XMLStringBuffer

extends XMLString {

    //

    // Constants

    //

    /** Default buffer size (32). */

    public static final int DEFAULT_SIZE = 32;

    //

    // Data

    //

    //

    // Constructors

    //

    /**

     *

     */

    public XMLStringBuffer() {

        this(DEFAULT_SIZE);

    } // <init>()

    /**

     *

     *

     * @param size

     */

    public XMLStringBuffer(int size) {

        ch = new char[size];

    } // <init>(int)

    /** Constructs a string buffer from a char. */

    public XMLStringBuffer(char c) {

        this(1);

        append(c);

    } // <init>(char)

    /** Constructs a string buffer from a String. */

    public XMLStringBuffer(String s) {

        this(s.length());

        append(s);

    } // <init>(String)

    /** Constructs a string buffer from the specified character array. */

    public XMLStringBuffer(char[] ch, int offset, int length) {

        this(length);

        append(ch, offset, length);

    } // <init>(char[],int,int)

    /** Constructs a string buffer from the specified XMLString. */

    public XMLStringBuffer(XMLString s) {

        this(s.length);

        append(s);

    } // <init>(XMLString)

    //

    // Public methods

    //

    /** Clears the string buffer. */

    public void clear() {

        offset = 0;

        length = 0;

    }

    /**

     * append

     *

     * @param c

     */

    public void append(char c) {

        if(this.length + 1 > this.ch.length){

            int newLength = this.ch.length * 2 ;

            if(newLength < this.ch.length + DEFAULT_SIZE){

                newLength = this.ch.length + DEFAULT_SIZE;

            }

            char [] tmp = new char[newLength];

            System.arraycopy(this.ch, 0, tmp, 0, this.length);

            this.ch = tmp;

        }

        this.ch[this.length] = c ;

        this.length++;

    } // append(char)

    /**

     * append

     *

     * @param s

     */

    public void append(String s) {

        int length = s.length();

        if (this.length + length > this.ch.length) {

            int newLength = this.ch.length * 2 ;

            if(newLength < this.ch.length + length + DEFAULT_SIZE){

                newLength = this.ch.length + length+ DEFAULT_SIZE;

            }

            char[] newch = new char[newLength];

            System.arraycopy(this.ch, 0, newch, 0, this.length);

            this.ch = newch;

        }

        s.getChars(0, length, this.ch, this.length);

        this.length += length;

    } // append(String)

    /**

     * append

     *

     * @param ch

     * @param offset

     * @param length

     */

    public void append(char[] ch, int offset, int length) {

        if (this.length + length > this.ch.length) {

            int newLength = this.ch.length * 2 ;

            if(newLength < this.ch.length + length + DEFAULT_SIZE){

                newLength = this.ch.length + length + DEFAULT_SIZE;

            }

            char[] newch = new char[newLength];

            System.arraycopy(this.ch, 0, newch, 0, this.length);

            this.ch = newch;

        }

        //making the code more robust as it would handle null or 0 length data,

        //add the data only when it contains some thing

        if(ch != null && length > 0){

            System.arraycopy(ch, offset, this.ch, this.length, length);

            this.length += length;

        }

    } // append(char[],int,int)

    /**

     * append

     *

     * @param s

     */

    public void append(XMLString s) {

        append(s.ch, s.offset, s.length);

    } // append(XMLString)

} // class XMLStringBuffer