/*
 * 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.impl.dtd.models;

import org.apache.xerces.impl.dtd.XMLContentSpec;
import org.apache.xerces.xni.QName;

MixedContentModel is a derivative of the abstract content model base
class that handles the special case of mixed model elements. If an element
is mixed model, it has PCDATA as its first possible content, followed
by an alternation of the possible children. The children cannot have any
numeration or order, so it must look like this:
  <!ELEMENT Foo ((#PCDATA|a|b|c|)*)>

So, all we have to do is to keep an array of the possible children and
validate by just looking up each child being validated by looking it up
in the list.
@xerces.internal
Version:
$Id: MixedContentModel.java 699892 2008-09-28 21:08:27Z mrglavas $/**
 * MixedContentModel is a derivative of the abstract content model base
 * class that handles the special case of mixed model elements. If an element
 * is mixed model, it has PCDATA as its first possible content, followed
 * by an alternation of the possible children. The children cannot have any
 * numeration or order, so it must look like this:
 * <pre>
 *   &lt;!ELEMENT Foo ((#PCDATA|a|b|c|)*)&gt;
 * </pre>
 * So, all we have to do is to keep an array of the possible children and
 * validate by just looking up each child being validated by looking it up
 * in the list.
 * 
 * @xerces.internal

 * 
 * @version $Id: MixedContentModel.java 699892 2008-09-28 21:08:27Z mrglavas $
 */
public class MixedContentModel
    implements ContentModelValidator {

    //
    // Data
    //

    
The count of possible children that we have to deal with. /** The count of possible children that we have to deal with. */
    private final int fCount;

    
The list of possible children that we have to accept. /** The list of possible children that we have to accept. */
    private final QName fChildren[];

    
The type of the children to support ANY. /** The type of the children to support ANY. */
    private final int fChildrenType[];

    /* this is the EquivClassComparator object */
    //private EquivClassComparator comparator = null;
    
    
True if mixed content model is ordered. DTD mixed content models
are always unordered.
/** 
     * True if mixed content model is ordered. DTD mixed content models
     * are <em>always</em> unordered.
     */
    private final boolean fOrdered;

    //
    // Constructors
    //

    
Constructs a mixed content model.
Params:
children – The list of allowed children.
type – The list of the types of the children.
offset – The start offset position in the children.
length – The child count.
ordered – True if content must be ordered./**
     * Constructs a mixed content model.
     *
     * @param children The list of allowed children.
     * @param type The list of the types of the children.
     * @param offset The start offset position in the children.
     * @param length The child count.
     * @param ordered True if content must be ordered.
     */
    public MixedContentModel(QName[] children, int[] type, int offset, int length , boolean ordered) {
        // Make our own copy now, which is exactly the right size
        fCount = length;
        fChildren = new QName[fCount];
        fChildrenType = new int[fCount];
        for (int i = 0; i < fCount; i++) {
            fChildren[i] = new QName(children[offset + i]);
            fChildrenType[i] = type[offset + i];
        }
        fOrdered = ordered;

    }

    //
    // ContentModelValidator methods
    //

    
    
Check that the specified content is valid according to this
content model. This method can also be called to do 'what if' 
testing of content models just to see if they would be valid.

A value of -1 in the children array indicates a PCDATA node. All other 
indexes will be positive and represent child elements. The count can be
zero, since some elements have the EMPTY content model and that must be 
confirmed.
Params:
children – The children of this element.  Each integer is an index within
                the StringPool of the child element name.  An index
                of -1 is used to indicate an occurrence of non-whitespace character
                data.
offset – Offset into the array where the children starts.
length – The number of entries in the children array.
Returns:
The value -1 if fully valid, else the 0 based index of the child
        that first failed. If the value returned is equal to the number
        of children, then the specified children are valid but additional
        content is required to reach a valid ending state./**
     * Check that the specified content is valid according to this
     * content model. This method can also be called to do 'what if' 
     * testing of content models just to see if they would be valid.
     * <p>
     * A value of -1 in the children array indicates a PCDATA node. All other 
     * indexes will be positive and represent child elements. The count can be
     * zero, since some elements have the EMPTY content model and that must be 
     * confirmed.
     *
     * @param children The children of this element.  Each integer is an index within
     *                 the <code>StringPool</code> of the child element name.  An index
     *                 of -1 is used to indicate an occurrence of non-whitespace character
     *                 data.
     * @param offset Offset into the array where the children starts.
     * @param length The number of entries in the <code>children</code> array.
     *
     * @return The value -1 if fully valid, else the 0 based index of the child
     *         that first failed. If the value returned is equal to the number
     *         of children, then the specified children are valid but additional
     *         content is required to reach a valid ending state.
     *
     */
    public int validate(QName[] children, int offset, int length) {
        
        // must match order
        if (fOrdered) {
            int inIndex = 0;
            for (int outIndex = 0; outIndex < length; outIndex++) {

                // ignore mixed text
                final QName curChild = children[offset + outIndex];
                if (curChild.localpart == null) {
                    continue;
                }

                // element must match
                int type = fChildrenType[inIndex];
                if (type == XMLContentSpec.CONTENTSPECNODE_LEAF) {
                    if (fChildren[inIndex].rawname != children[offset + outIndex].rawname) {
                        return outIndex;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY) {
                    String uri = fChildren[inIndex].uri;
                    if (uri != null && uri != children[outIndex].uri) {
                        return outIndex;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_LOCAL) {
                    if (children[outIndex].uri != null) {
                        return outIndex;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_OTHER) {
                    if (fChildren[inIndex].uri == children[outIndex].uri) {
                        return outIndex;
                    }
                }
                
                // advance index
                inIndex++;
            }
        }

        // can appear in any order
        else {
            for (int outIndex = 0; outIndex < length; outIndex++)
            {
                // Get the current child out of the source index
                final QName curChild = children[offset + outIndex];
    
                // If its PCDATA, then we just accept that
                if (curChild.localpart == null)
                    continue;
    
                // And try to find it in our list
                int inIndex = 0;
                for (; inIndex < fCount; inIndex++)
                {
                    int type = fChildrenType[inIndex];
                    if (type == XMLContentSpec.CONTENTSPECNODE_LEAF) {
                        if (curChild.rawname == fChildren[inIndex].rawname) {
                            break;
                        }
                    }
                    else if (type == XMLContentSpec.CONTENTSPECNODE_ANY) {
                        String uri = fChildren[inIndex].uri;
                        if (uri == null || uri == children[outIndex].uri) {
                            break;
                        }
                    }
                    else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_LOCAL) {
                        if (children[outIndex].uri == null) {
                            break;
                        }
                    }
                    else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_OTHER) {
                        if (fChildren[inIndex].uri != children[outIndex].uri) {
                            break;
                        }
                    }
                    // REVISIT: What about checking for multiple ANY matches?
                    //          The content model ambiguity *could* be checked
                    //          by the caller before constructing the mixed
                    //          content model.
                }

                // We did not find this one, so the validation failed
                if (inIndex == fCount)
                    return outIndex;
            }
        }

        // Everything seems to be in order, so return success
        return -1;
    } // validate

} // class MixedContentModel