/*

 * 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.

 */

/*

 * $Id:  $

 */

package com.sun.org.apache.xml.internal.serializer.dom3;

import java.util.Enumeration;

import java.util.NoSuchElementException;

/**

 * Namespace support for XML document handlers. This class doesn't

 * perform any error checking and assumes that all strings passed

 * as arguments to methods are unique symbols. The SymbolTable class

 * can be used for this purpose.

 *

 * Derived from org.apache.xerces.util.NamespaceSupport

 *

 * @author Andy Clark, IBM

 *

 * @version $Id: Exp $

 */

public class NamespaceSupport {

        static final String PREFIX_XML = "xml".intern();

        static final String PREFIX_XMLNS = "xmlns".intern();

    /**

     * The XML Namespace ("http://www.w3.org/XML/1998/namespace"). This is

     * the Namespace URI that is automatically mapped to the "xml" prefix.

     */

    public final static String XML_URI = "http://www.w3.org/XML/1998/namespace".intern();

    /**

     * XML Information Set REC

     * all namespace attributes (including those named xmlns,

     * whose [prefix] property has no value) have a namespace URI of http://www.w3.org/2000/xmlns/

     */

    public final static String XMLNS_URI = "http://www.w3.org/2000/xmlns/".intern();

        //

    // Data

    //

    /**

     * Namespace binding information. This array is composed of a

     * series of tuples containing the namespace binding information:

     * <prefix, uri>. The default size can be set to anything

     * as long as it is a power of 2 greater than 1.

     *

     * @see #fNamespaceSize

     * @see #fContext

     */

    protected String[] fNamespace = new String[16 * 2];

    /** The top of the namespace information array. */

    protected int fNamespaceSize;

    // NOTE: The constructor depends on the initial context size

    //       being at least 1. -Ac

    /**

     * Context indexes. This array contains indexes into the namespace

     * information array. The index at the current context is the start

     * index of declared namespace bindings and runs to the size of the

     * namespace information array.

     *

     * @see #fNamespaceSize

     */

    protected int[] fContext = new int[8];

    /** The current context. */

    protected int fCurrentContext;

    protected String[] fPrefixes = new String[16];

    //

    // Constructors

    //

    /** Default constructor. */

    public NamespaceSupport() {

    } // <init>()

    //

    // Public methods

    //

        /**

         * @see org.apache.xerces.xni.NamespaceContext#reset()

         */

    public void reset() {

        // reset namespace and context info

        fNamespaceSize = 0;

        fCurrentContext = 0;

        fContext[fCurrentContext] = fNamespaceSize;

        // bind "xml" prefix to the XML uri

        fNamespace[fNamespaceSize++] = PREFIX_XML;

        fNamespace[fNamespaceSize++] = XML_URI;

        // bind "xmlns" prefix to the XMLNS uri

        fNamespace[fNamespaceSize++] = PREFIX_XMLNS;

        fNamespace[fNamespaceSize++] = XMLNS_URI;

        ++fCurrentContext;

    } // reset(SymbolTable)

        /**

         * @see org.apache.xerces.xni.NamespaceContext#pushContext()

         */

    public void pushContext() {

        // extend the array, if necessary

        if (fCurrentContext + 1 == fContext.length) {

            int[] contextarray = new int[fContext.length * 2];

            System.arraycopy(fContext, 0, contextarray, 0, fContext.length);

            fContext = contextarray;

        }

        // push context

        fContext[++fCurrentContext] = fNamespaceSize;

    } // pushContext()

        /**

         * @see org.apache.xerces.xni.NamespaceContext#popContext()

         */

    public void popContext() {

        fNamespaceSize = fContext[fCurrentContext--];

    } // popContext()

        /**

         * @see org.apache.xerces.xni.NamespaceContext#declarePrefix(String, String)

         */

    public boolean declarePrefix(String prefix, String uri) {

        // ignore "xml" and "xmlns" prefixes

        if (prefix == PREFIX_XML || prefix == PREFIX_XMLNS) {

            return false;

        }

        // see if prefix already exists in current context

        for (int i = fNamespaceSize; i > fContext[fCurrentContext]; i -= 2) {

            //if (fNamespace[i - 2] == prefix) {

                if (fNamespace[i - 2].equals(prefix) )  {

                // REVISIT: [Q] Should the new binding override the

                //          previously declared binding or should it

                //          it be ignored? -Ac

                // NOTE:    The SAX2 "NamespaceSupport" helper allows

                //          re-bindings with the new binding overwriting

                //          the previous binding. -Ac

                fNamespace[i - 1] = uri;

                return true;

            }

        }

        // resize array, if needed

        if (fNamespaceSize == fNamespace.length) {

            String[] namespacearray = new String[fNamespaceSize * 2];

            System.arraycopy(fNamespace, 0, namespacearray, 0, fNamespaceSize);

            fNamespace = namespacearray;

        }

        // bind prefix to uri in current context

        fNamespace[fNamespaceSize++] = prefix;

        fNamespace[fNamespaceSize++] = uri;

        return true;

    } // declarePrefix(String,String):boolean

        /**

         * @see org.apache.xerces.xni.NamespaceContext#getURI(String)

         */

    public String getURI(String prefix) {

        // find prefix in current context

        for (int i = fNamespaceSize; i > 0; i -= 2) {

            //if (fNamespace[i - 2] == prefix) {

                if (fNamespace[i - 2].equals(prefix) ) {

                return fNamespace[i - 1];

            }

        }

        // prefix not found

        return null;

    } // getURI(String):String

        /**

         * @see org.apache.xerces.xni.NamespaceContext#getPrefix(String)

         */

    public String getPrefix(String uri) {

        // find uri in current context

        for (int i = fNamespaceSize; i > 0; i -= 2) {

            //if (fNamespace[i - 1] == uri) {

                if (fNamespace[i - 1].equals(uri) ) {

                //if (getURI(fNamespace[i - 2]) == uri)

                        if (getURI(fNamespace[i - 2]).equals(uri) )

                    return fNamespace[i - 2];

            }

        }

        // uri not found

        return null;

    } // getPrefix(String):String

        /**

         * @see org.apache.xerces.xni.NamespaceContext#getDeclaredPrefixCount()

         */

    public int getDeclaredPrefixCount() {

        return (fNamespaceSize - fContext[fCurrentContext]) / 2;

    } // getDeclaredPrefixCount():int

        /**

         * @see org.apache.xerces.xni.NamespaceContext#getDeclaredPrefixAt(int)

         */

    public String getDeclaredPrefixAt(int index) {

        return fNamespace[fContext[fCurrentContext] + index * 2];

    } // getDeclaredPrefixAt(int):String

        /**

         * @see org.apache.xerces.xni.NamespaceContext#getAllPrefixes()

         */

        public Enumeration getAllPrefixes() {

        int count = 0;

        if (fPrefixes.length < (fNamespace.length/2)) {

            // resize prefix array

            String[] prefixes = new String[fNamespaceSize];

            fPrefixes = prefixes;

        }

        String prefix = null;

        boolean unique = true;

        for (int i = 2; i < (fNamespaceSize-2); i += 2) {

            prefix = fNamespace[i + 2];

            for (int k=0;k<count;k++){

                if (fPrefixes[k]==prefix){

                    unique = false;

                    break;

                }

            }

            if (unique){

                fPrefixes[count++] = prefix;

            }

            unique = true;

        }

                return new Prefixes(fPrefixes, count);

        }

    protected final class Prefixes implements Enumeration {

        private String[] prefixes;

        private int counter = 0;

        private int size = 0;

                /**

                 * Constructor for Prefixes.

                 */

                public Prefixes(String [] prefixes, int size) {

                        this.prefixes = prefixes;

            this.size = size;

                }

       /**

                 * @see java.util.Enumeration#hasMoreElements()

                 */

                public boolean hasMoreElements() {

                        return (counter< size);

                }

                /**

                 * @see java.util.Enumeration#nextElement()

                 */

                public Object nextElement() {

            if (counter< size){

                return fPrefixes[counter++];

            }

                        throw new NoSuchElementException("Illegal access to Namespace prefixes enumeration.");

                }

        public String toString(){

            StringBuffer buf = new StringBuffer();

            for (int i=0;i<size;i++){

                buf.append(prefixes[i]);

                buf.append(" ");

            }

            return buf.toString();

        }

}

} // class NamespaceSupport