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 * Copyright  1999-2004 The Apache Software Foundation.
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package com.sun.org.apache.xml.internal.security.c14n.implementations;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;


import org.w3c.dom.Attr;
import org.w3c.dom.Node;



A stack based Symble Table.

For speed reasons all the symbols are introduced in the same map,
and at the same time in a list so it can be removed when the frame is pop back.
Author:
Raul Benito/**
 * A stack based Symble Table.
 *<br>For speed reasons all the symbols are introduced in the same map,
 * and at the same time in a list so it can be removed when the frame is pop back.
 * @author Raul Benito
 **/
public class NameSpaceSymbTable {

        
The map betwen prefix-> entry table. /**The map betwen prefix-> entry table. */
        SymbMap symb;
        
The level of nameSpaces (for Inclusive visibility)./**The level of nameSpaces (for Inclusive visibility).*/
        int nameSpaces=0;
        
The stacks for removing the definitions when doing pop./**The stacks for removing the definitions when doing pop.*/
        List level;
    boolean cloned=true;
        static final String XMLNS="xmlns";
        final static SymbMap initialMap=new SymbMap();
        static {
                NameSpaceSymbEntry ne=new NameSpaceSymbEntry("",null,true,XMLNS);
                ne.lastrendered="";
                initialMap.put(XMLNS,ne);
        }
    
Default constractor
/**
     * Default constractor
     **/
    public NameSpaceSymbTable() {
        level = new ArrayList(10);
        //Insert the default binding for xmlns.
        symb=(SymbMap) initialMap.clone();
    }

    
Get all the unrendered nodes in the name space.
For Inclusive rendering
Params:
result – the list where to fill the unrendered xmlns definitions./**
         * Get all the unrendered nodes in the name space.
         * For Inclusive rendering
     * @param result the list where to fill the unrendered xmlns definitions.
         **/
        public  void getUnrenderedNodes(Collection result) {
           //List result=new ArrayList();
           Iterator it=symb.entrySet().iterator();
           while (it.hasNext()) {
                        NameSpaceSymbEntry n=(NameSpaceSymbEntry)(it.next());
                        //put them rendered?
                        if ((!n.rendered) && (n.n!=null)) {
                                n=(NameSpaceSymbEntry) n.clone();
                needsClone();
                symb.put(n.prefix,n);
                n.lastrendered=n.uri;
                n.rendered=true;

                                result.add(n.n);

                        }
           }
        }

        
Push a frame for visible namespace.
For Inclusive rendering.
/**
     * Push a frame for visible namespace.
     * For Inclusive rendering.
     **/
        public void outputNodePush() {
                nameSpaces++;
                push();
        }

        
Pop a frame for visible namespace.
/**
     * Pop a frame for visible namespace.
     **/
        public void outputNodePop() {
                nameSpaces--;
                pop();
        }

        
Push a frame for a node.
Inclusive or Exclusive.
/**
     * Push a frame for a node.
     * Inclusive or Exclusive.
     **/
        public void push() {
                //Put the number of namespace definitions in the stack.
        level.add(null);
        cloned=false;
        }

        
Pop a frame.
Inclusive or Exclusive.
/**
     * Pop a frame.
     * Inclusive or Exclusive.
     **/
        public void pop() {
        int size=level.size()-1;
        Object ob= level.remove(size);
        if (ob!=null) {
                symb=(SymbMap)ob;
            if (size==0) {
               cloned=false;
            } else
                cloned=(level.get(size-1)!=symb);
        } else {
                cloned=false;
        }


        }

        final void needsClone() {
                if (!cloned) {
            level.set(level.size()-1,symb);
                        symb=(SymbMap) symb.clone();
            cloned=true;
        }
    }


        
Gets the attribute node that defines the binding for the prefix.
Params:
prefix – the prefix to obtain the attribute.
Returns:
null if there is no need to render the prefix. Otherwise the node of
definition./**
         * Gets the attribute node that defines the binding for the prefix.
     * @param prefix the prefix to obtain the attribute.
     * @return null if there is no need to render the prefix. Otherwise the node of
     * definition.
     **/
        public Attr getMapping(String prefix) {
                NameSpaceSymbEntry entry=symb.get(prefix);
                if (entry==null) {
                        //There is no definition for the prefix(a bug?).
                        return null;
                }
                if (entry.rendered) {
                        //No need to render an entry already rendered.
                        return null;
                }
                // Mark this entry as render.
        entry=(NameSpaceSymbEntry) entry.clone();
        needsClone();
        symb.put(prefix,entry);
                entry.rendered=true;
                entry.level=nameSpaces;
                entry.lastrendered=entry.uri;
                // Return the node for outputing.
                return entry.n;
        }

        
Gets a definition without mark it as render.
For render in exclusive c14n the namespaces in the include prefixes.
Params:
prefix – The prefix whose definition is neaded.
Returns:
the attr to render, null if there is no need to render/**
     * Gets a definition without mark it as render.
     * For render in exclusive c14n the namespaces in the include prefixes.
     * @param prefix The prefix whose definition is neaded.
     * @return the attr to render, null if there is no need to render
     **/
        public Attr getMappingWithoutRendered(String prefix) {
                NameSpaceSymbEntry entry= symb.get(prefix);
                if (entry==null) {
                        return null;
                }
                if (entry.rendered) {
                        return null;
                }
                return entry.n;
        }

        
Adds the mapping for a prefix.
Params:
prefix – the prefix of definition
uri – the Uri of the definition
n – the attribute that have the definition
Returns:
true if there is already defined./**
     * Adds the mapping for a prefix.
     * @param prefix the prefix of definition
     * @param uri the Uri of the definition
     * @param n the attribute that have the definition
     * @return true if there is already defined.
     **/
        public boolean addMapping(String prefix, String uri,Attr n) {
                NameSpaceSymbEntry ob = symb.get(prefix);
                if ((ob!=null) && uri.equals(ob.uri)) {
                        //If we have it previously defined. Don't keep working.
                        return false;
                }
                //Creates and entry in the table for this new definition.
                NameSpaceSymbEntry ne=new NameSpaceSymbEntry(uri,n,false,prefix);
        needsClone();
                symb.put(prefix, ne);
                if (ob != null) {
                        //We have a previous definition store it for the pop.
                        //Check if a previous definition(not the inmidiatly one) has been rendered.
                        ne.lastrendered=ob.lastrendered;
                        if ((ob.lastrendered!=null)&& (ob.lastrendered.equals(uri))) {
                                //Yes it is. Mark as rendered.
                                ne.rendered=true;
                        }
                }
        return true;
        }

    
Adds a definition and mark it as render.
For inclusive c14n.
Params:
prefix – the prefix of definition
uri – the Uri of the definition
n – the attribute that have the definition
Returns:
the attr to render, null if there is no need to render/**
     * Adds a definition and mark it as render.
     * For inclusive c14n.
     * @param prefix the prefix of definition
     * @param uri the Uri of the definition
     * @param n the attribute that have the definition
     * @return the attr to render, null if there is no need to render
     **/
    public Node addMappingAndRender(String prefix, String uri,Attr n) {
        NameSpaceSymbEntry ob = symb.get(prefix);

        if ((ob!=null) && uri.equals(ob.uri)) {
            if (!ob.rendered) {
                ob=(NameSpaceSymbEntry) ob.clone();
                needsClone();
                symb.put(prefix,ob);
                ob.lastrendered=uri;
                ob.rendered=true;
                return ob.n;
            }
            return null;
        }

        NameSpaceSymbEntry ne=new NameSpaceSymbEntry(uri,n,true,prefix);
        ne.lastrendered=uri;
        needsClone();
        symb.put(prefix, ne);
        if (ob != null) {

            if ((ob.lastrendered!=null)&& (ob.lastrendered.equals(uri))) {
                ne.rendered=true;
                return null;
            }
        }
        return ne.n;
    }

        public int getLevel() {
                // TODO Auto-generated method stub
                return level.size();
        }

        public void removeMapping(String prefix) {
                NameSpaceSymbEntry ob = symb.get(prefix);

        if (ob!=null) {
            needsClone();
            symb.put(prefix,null);
        }
        }

        public void removeMappingIfNotRender(String prefix) {
                NameSpaceSymbEntry ob = symb.get(prefix);

        if (ob!=null && !ob.rendered) {
            needsClone();
            symb.put(prefix,null);
        }
        }

        public boolean removeMappingIfRender(String prefix) {
                NameSpaceSymbEntry ob = symb.get(prefix);

        if (ob!=null && ob.rendered) {
            needsClone();
            symb.put(prefix,null);
        }
        return false;
        }
}

The internal structure of NameSpaceSymbTable.
/**
 * The internal structure of NameSpaceSymbTable.
 **/
class NameSpaceSymbEntry implements Cloneable {
    NameSpaceSymbEntry(String name,Attr n,boolean rendered,String prefix) {
        this.uri=name;
        this.rendered=rendered;
        this.n=n;
        this.prefix=prefix;
    }
    
@inheritDoc
/** @inheritDoc */
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            return null;
        }
    }
    
The level where the definition was rendered(Only for inclusive) /** The level where the definition was rendered(Only for inclusive) */
    int level=0;
    String prefix;
    
The URI that the prefix defines /**The URI that the prefix defines */
    String uri;
    
The last output in the URI for this prefix (This for speed reason)./**The last output in the URI for this prefix (This for speed reason).*/
    String lastrendered=null;
    
This prefix-URI has been already render or not./**This prefix-URI has been already render or not.*/
    boolean rendered=false;
    
The attribute to include./**The attribute to include.*/
    Attr n;
};

class SymbMap implements Cloneable {
    int free=23;
    NameSpaceSymbEntry[] entries;
    String[] keys;
        SymbMap() {
                entries=new NameSpaceSymbEntry[free];
                keys=new String[free];
        }
    void put(String key, NameSpaceSymbEntry value) {
        int index = index(key);
        Object oldKey = keys[index];
        keys[index] = key;
        entries[index] = value;
        if (oldKey==null || !oldKey.equals(key)) {
            if (--free == 0) {
                free=entries.length;
                int newCapacity = free<<2;
                rehash(newCapacity);
            }
        }
    }

    List entrySet() {
        List a=new ArrayList();
        for (int i=0;i<entries.length;i++) {
                if ((entries[i]!=null) && !("".equals(entries[i].uri))) {
                        a.add(entries[i]);
            }
        }
        return a;
    }

    protected int index(Object obj) {
        Object[] set = keys;
        int length = set.length;
        //abs of index
        int index = (obj.hashCode() & 0x7fffffff) %  length;
        Object cur = set[index];

        if (cur == null || (cur.equals( obj))) {
                return index;
        }
        length=length-1;
        do {
                index=index==length? 0:++index;
                cur = set[index];
        } while (cur != null && (!cur.equals(obj)));
        return index;
    }

    
rehashes the map to the new capacity.
Params:
newCapacity – an int value/**
     * rehashes the map to the new capacity.
     *
     * @param newCapacity an <code>int</code> value
     */
    protected void rehash(int newCapacity) {
        int oldCapacity = keys.length;
        String oldKeys[] = keys;
        NameSpaceSymbEntry oldVals[] = entries;

        keys = new String[newCapacity];
        entries = new NameSpaceSymbEntry[newCapacity];

        for (int i = oldCapacity; i-- > 0;) {
            if(oldKeys[i] != null) {
                String o = oldKeys[i];
                int index = index(o);
                keys[index] = o;
                entries[index] = oldVals[i];
            }
        }
    }

    NameSpaceSymbEntry get(String key) {
        return  entries[index(key)];
    }

    protected Object clone()  {
        try {
                SymbMap copy=(SymbMap) super.clone();
                copy.entries=new NameSpaceSymbEntry[entries.length];
                System.arraycopy(entries,0,copy.entries,0,entries.length);
                copy.keys=new String[keys.length];
                System.arraycopy(keys,0,copy.keys,0,keys.length);

                return copy;
        } catch (CloneNotSupportedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}