java/15 : java.xml/com/sun/org/apache/xerces/internal/impl/dtd/models/DFAContentModel.java

DFAContentModel
https://openjdk.java.net/
GPLv2 + Classpath Exception
/*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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.impl.dtd.models;

import com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec;
import com.sun.org.apache.xerces.internal.xni.QName;
import java.util.HashMap;
import java.util.Map;

DFAContentModel is the derivative of ContentModel that does
all of the non-trivial element content validation. This class does
the conversion from the regular expression to the DFA that
it then uses in its validation algorithm.

Note: Upstream work insures that this class will never see
a content model with PCDATA in it. Any model with PCDATA is 'mixed'
and is handled via the MixedContentModel class since mixed models
are very constrained in form and easily handled via a special case.
This also makes implementation of this class much easier.
@xerces.internal 
@LastModified : Oct 2017/**

 * DFAContentModel is the derivative of ContentModel that does
 * all of the non-trivial element content validation. This class does
 * the conversion from the regular expression to the DFA that
 * it then uses in its validation algorithm.
 * <p>
 * <b>Note:</b> Upstream work insures that this class will never see
 * a content model with PCDATA in it. Any model with PCDATA is 'mixed'
 * and is handled via the MixedContentModel class since mixed models
 * are very constrained in form and easily handled via a special case.
 * This also makes implementation of this class much easier.
 *
 * @xerces.internal
 *
 * @LastModified: Oct 2017
 */
public class DFAContentModel
    implements ContentModelValidator {

    //
    // Constants
    //
    // special strings

    Epsilon string. /** Epsilon string. */
    private static String fEpsilonString = "<<CMNODE_EPSILON>>";

    End-of-content string. /** End-of-content string. */
    private static String fEOCString = "<<CMNODE_EOC>>";

    initializing static members /** initializing static members **/
    static {
        fEpsilonString = fEpsilonString.intern();
        fEOCString = fEOCString.intern();
    }

    // debugging

    Set to true to debug content model validation. /** Set to true to debug content model validation. */
    private static final boolean DEBUG_VALIDATE_CONTENT = false;

    //
    // Data
    //

    /* this is the EquivClassComparator object */
    //private EquivClassComparator comparator = null;

    This is the map of unique input symbol elements to indices into
each state's per-input symbol transition table entry. This is part
of the built DFA information that must be kept around to do the
actual validation.
/**
     * This is the map of unique input symbol elements to indices into
     * each state's per-input symbol transition table entry. This is part
     * of the built DFA information that must be kept around to do the
     * actual validation.
     */
    private QName fElemMap[] = null;

    This is a map of whether the element map contains information
related to ANY models.
/**
     * This is a map of whether the element map contains information
     * related to ANY models.
     */
    private int fElemMapType[] = null;

    The element map size. /** The element map size. */
    private int fElemMapSize = 0;

    Boolean to distinguish Schema Mixed Content /** Boolean to distinguish Schema Mixed Content */
    private boolean fMixed;

    The NFA position of the special EOC (end of content) node. This
is saved away since it's used during the DFA build.
/**
     * The NFA position of the special EOC (end of content) node. This
     * is saved away since it's used during the DFA build.
     */
    private int fEOCPos = 0;


    This is an array of booleans, one per state (there are
fTransTableSize states in the DFA) that indicates whether that
state is a final state.
/**
     * This is an array of booleans, one per state (there are
     * fTransTableSize states in the DFA) that indicates whether that
     * state is a final state.
     */
    private boolean fFinalStateFlags[] = null;

    The list of follow positions for each NFA position (i.e. for each
non-epsilon leaf node.) This is only used during the building of
the DFA, and is let go afterwards.
/**
     * The list of follow positions for each NFA position (i.e. for each
     * non-epsilon leaf node.) This is only used during the building of
     * the DFA, and is let go afterwards.
     */
    private CMStateSet fFollowList[] = null;

    This is the head node of our intermediate representation. It is
only non-null during the building of the DFA (just so that it
does not have to be passed all around.) Once the DFA is built,
this is no longer required so its nulled out.
/**
     * This is the head node of our intermediate representation. It is
     * only non-null during the building of the DFA (just so that it
     * does not have to be passed all around.) Once the DFA is built,
     * this is no longer required so its nulled out.
     */
    private CMNode fHeadNode = null;

    The count of leaf nodes. This is an important number that set some
limits on the sizes of data structures in the DFA process.
/**
     * The count of leaf nodes. This is an important number that set some
     * limits on the sizes of data structures in the DFA process.
     */
    private int fLeafCount = 0;

    An array of non-epsilon leaf nodes, which is used during the DFA
build operation, then dropped.
/**
     * An array of non-epsilon leaf nodes, which is used during the DFA
     * build operation, then dropped.
     */
    private CMLeaf fLeafList[] = null;

    Array mapping ANY types to the leaf list. /** Array mapping ANY types to the leaf list. */
    private int fLeafListType[] = null;

    //private ContentLeafNameTypeVector fLeafNameTypeVector = null;

    /**
     * The string pool of our parser session. This is set during construction
     * and kept around.
     */
    //private StringPool fStringPool = null;

    This is the transition table that is the main by product of all
of the effort here. It is an array of arrays of ints. The first
dimension is the number of states we end up with in the DFA. The
second dimensions is the number of unique elements in the content
model (fElemMapSize). Each entry in the second dimension indicates
the new state given that input for the first dimension's start
state.

The fElemMap array handles mapping from element indexes to
positions in the second dimension of the transition table.
/**
     * This is the transition table that is the main by product of all
     * of the effort here. It is an array of arrays of ints. The first
     * dimension is the number of states we end up with in the DFA. The
     * second dimensions is the number of unique elements in the content
     * model (fElemMapSize). Each entry in the second dimension indicates
     * the new state given that input for the first dimension's start
     * state.
     * <p>
     * The fElemMap array handles mapping from element indexes to
     * positions in the second dimension of the transition table.
     */
    private int fTransTable[][] = null;

    The number of valid entries in the transition table, and in the other
related tables such as fFinalStateFlags.
/**
     * The number of valid entries in the transition table, and in the other
     * related tables such as fFinalStateFlags.
     */
    private int fTransTableSize = 0;

    Flag that indicates that even though we have a "complicated"
content model, it is valid to have no content. In other words,
all parts of the content model are optional. For example:
     <!ELEMENT AllOptional (Optional*,NotRequired?)>

/**
     * Flag that indicates that even though we have a "complicated"
     * content model, it is valid to have no content. In other words,
     * all parts of the content model are optional. For example:
     * <pre>
     *      &lt;!ELEMENT AllOptional (Optional*,NotRequired?)&gt;
     * </pre>
     */
    private boolean fEmptyContentIsValid = false;

    // temp variables

    Temporary qualified name. /** Temporary qualified name. */
    private final QName fQName = new QName();

    //
    // Constructors
    //


    //
    // Constructors
    //

    Constructs a DFA content model.
Params: syntaxTree –    The syntax tree of the content model.
leafCount –     The number of leaves.
mixed – /**
     * Constructs a DFA content model.
     *
     * @param syntaxTree    The syntax tree of the content model.
     * @param leafCount     The number of leaves.
     * @param mixed
     *
     */
    public DFAContentModel(CMNode syntaxTree, int leafCount, boolean mixed) {
        // Store away our index and pools in members
        //fStringPool = stringPool;
        fLeafCount = leafCount;


        // this is for Schema Mixed Content
        fMixed = mixed;

        //
        //  Ok, so lets grind through the building of the DFA. This method
        //  handles the high level logic of the algorithm, but it uses a
        //  number of helper classes to do its thing.
        //
        //  In order to avoid having hundreds of references to the error and
        //  string handlers around, this guy and all of his helper classes
        //  just throw a simple exception and we then pass it along.
        //
        buildDFA(syntaxTree);
    }

    //
    // 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) {

        if (DEBUG_VALIDATE_CONTENT)
            System.out.println("DFAContentModel#validateContent");

        //
        // A DFA content model must *always* have at least 1 child
        // so a failure is given if no children present.
        //
        // Defect 782: This is an incorrect statement because a DFA
        // content model is also used for constructions such as:
        //
        //     (Optional*,NotRequired?)
        //
        // where a perfectly valid content would be NO CHILDREN.
        // Therefore, if there are no children, we must check to
        // see if the CMNODE_EOC marker is a valid start state! -Ac
        //
        if (length == 0) {
            if (DEBUG_VALIDATE_CONTENT) {
                System.out.println("!!! no children");
                System.out.println("elemMap="+fElemMap);
                for (int i = 0; i < fElemMap.length; i++) {
                    String uri = fElemMap[i].uri;
                    String localpart = fElemMap[i].localpart;

                    System.out.println("fElemMap["+i+"]="+uri+","+
                                       localpart+" ("+
                                       uri+", "+
                                       localpart+
                                       ')');

                }
                System.out.println("EOCIndex="+fEOCString);
            }

            return fEmptyContentIsValid ? -1 : 0;

        } // if child count == 0

        //
        //  Lets loop through the children in the array and move our way
        //  through the states. Note that we use the fElemMap array to map
        //  an element index to a state index.
        //
        int curState = 0;
        for (int childIndex = 0; childIndex < length; childIndex++)
        {
            // Get the current element index out
            final QName curElem = children[offset + childIndex];
            // ignore mixed text
            if (fMixed && curElem.localpart == null) {
                continue;
            }

            // Look up this child in our element map
            int elemIndex = 0;
            for (; elemIndex < fElemMapSize; elemIndex++)
            {
                int type = fElemMapType[elemIndex] & 0x0f ;
                if (type == XMLContentSpec.CONTENTSPECNODE_LEAF) {
                    //System.out.println("fElemMap["+elemIndex+"]: "+fElemMap[elemIndex]);
                    if (fElemMap[elemIndex].rawname == curElem.rawname) {
                        break;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY) {
                    String uri = fElemMap[elemIndex].uri;
                    if (uri == null || uri == curElem.uri) {
                        break;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_LOCAL) {
                    if (curElem.uri == null) {
                        break;
                    }
                }
                else if (type == XMLContentSpec.CONTENTSPECNODE_ANY_OTHER) {
                    if (fElemMap[elemIndex].uri != curElem.uri) {
                        break;
                    }
                }
            }

            // If we didn't find it, then obviously not valid
            if (elemIndex == fElemMapSize) {
                if (DEBUG_VALIDATE_CONTENT) {
                    System.out.println("!!! didn't find it");

                    System.out.println("curElem : " +curElem );
                    for (int i=0; i<fElemMapSize; i++) {
                        System.out.println("fElemMap["+i+"] = " +fElemMap[i] );
                        System.out.println("fElemMapType["+i+"] = " +fElemMapType[i] );
                    }
                }

                return childIndex;
            }

            //
            //  Look up the next state for this input symbol when in the
            //  current state.
            //
            curState = fTransTable[curState][elemIndex];

            // If its not a legal transition, then invalid
            if (curState == -1) {
                if (DEBUG_VALIDATE_CONTENT)
                    System.out.println("!!! not a legal transition");
                return childIndex;
            }
        }

        //
        //  We transitioned all the way through the input list. However, that
        //  does not mean that we ended in a final state. So check whether
        //  our ending state is a final state.
        //
        if (DEBUG_VALIDATE_CONTENT)
            System.out.println("curState="+curState+", childCount="+length);
        if (!fFinalStateFlags[curState])
            return length;

        // success!
        return -1;
    } // validate


    //
    // Private methods
    //

    Builds the internal DFA transition table from the given syntax tree.
Params: syntaxTree – The syntax tree.
Throws: CMException – Thrown if DFA cannot be built./**
     * Builds the internal DFA transition table from the given syntax tree.
     *
     * @param syntaxTree The syntax tree.
     *
     * @exception CMException Thrown if DFA cannot be built.
     */
    private void buildDFA(CMNode syntaxTree)
    {
        //
        //  The first step we need to take is to rewrite the content model
        //  using our CMNode objects, and in the process get rid of any
        //  repetition short cuts, converting them into '*' style repetitions
        //  or getting rid of repetitions altogether.
        //
        //  The conversions done are:
        //
        //  x+ -> (x|x*)
        //  x? -> (x|epsilon)
        //
        //  This is a relatively complex scenario. What is happening is that
        //  we create a top level binary node of which the special EOC value
        //  is set as the right side node. The the left side is set to the
        //  rewritten syntax tree. The source is the original content model
        //  info from the decl pool. The rewrite is done by buildSyntaxTree()
        //  which recurses the decl pool's content of the element and builds
        //  a new tree in the process.
        //
        //  Note that, during this operation, we set each non-epsilon leaf
        //  node's DFA state position and count the number of such leafs, which
        //  is left in the fLeafCount member.
        //
        //  The nodeTmp object is passed in just as a temp node to use during
        //  the recursion. Otherwise, we'd have to create a new node on every
        //  level of recursion, which would be piggy in Java (as is everything
        //  for that matter.)
        //

        /* MODIFIED (Jan, 2001)
         *
         * Use following rules.
         *   nullable(x+) := nullable(x), first(x+) := first(x),  last(x+) := last(x)
         *   nullable(x?) := true, first(x?) := first(x),  last(x?) := last(x)
         *
         * The same computation of follow as x* is applied to x+
         *
         * The modification drastically reduces computation time of
         * "(a, (b, a+, (c, (b, a+)+, a+, (d,  (c, (b, a+)+, a+)+, (b, a+)+, a+)+)+)+)+"
         */

        fQName.setValues(null, fEOCString, fEOCString, null);
        CMLeaf nodeEOC = new CMLeaf(fQName);
        fHeadNode = new CMBinOp
        (
            XMLContentSpec.CONTENTSPECNODE_SEQ
            , syntaxTree
            , nodeEOC
        );

        //
        //  And handle specially the EOC node, which also must be numbered
        //  and counted as a non-epsilon leaf node. It could not be handled
        //  in the above tree build because it was created before all that
        //  started. We save the EOC position since its used during the DFA
        //  building loop.
        //
        fEOCPos = fLeafCount;
        nodeEOC.setPosition(fLeafCount++);

        //
        //  Ok, so now we have to iterate the new tree and do a little more
        //  work now that we know the leaf count. One thing we need to do is
        //  to calculate the first and last position sets of each node. This
        //  is cached away in each of the nodes.
        //
        //  Along the way we also set the leaf count in each node as the
        //  maximum state count. They must know this in order to create their
        //  first/last pos sets.
        //
        //  We also need to build an array of references to the non-epsilon
        //  leaf nodes. Since we iterate it in the same way as before, this
        //  will put them in the array according to their position values.
        //
        fLeafList = new CMLeaf[fLeafCount];
        fLeafListType = new int[fLeafCount];
        postTreeBuildInit(fHeadNode, 0);

        //
        //  And, moving onward... We now need to build the follow position
        //  sets for all the nodes. So we allocate an array of state sets,
        //  one for each leaf node (i.e. each DFA position.)
        //
        fFollowList = new CMStateSet[fLeafCount];
        for (int index = 0; index < fLeafCount; index++)
            fFollowList[index] = new CMStateSet(fLeafCount);
        calcFollowList(fHeadNode);
        //
        //  And finally the big push... Now we build the DFA using all the
        //  states and the tree we've built up. First we set up the various
        //  data structures we are going to use while we do this.
        //
        //  First of all we need an array of unique element names in our
        //  content model. For each transition table entry, we need a set of
        //  contiguous indices to represent the transitions for a particular
        //  input element. So we need to a zero based range of indexes that
        //  map to element types. This element map provides that mapping.
        //
        fElemMap = new QName[fLeafCount];
        fElemMapType = new int[fLeafCount];
        fElemMapSize = 0;
        for (int outIndex = 0; outIndex < fLeafCount; outIndex++)
        {
            fElemMap[outIndex] = new QName();

            /****
            if ( (fLeafListType[outIndex] & 0x0f) != 0 ) {
                if (fLeafNameTypeVector == null) {
                    fLeafNameTypeVector = new ContentLeafNameTypeVector();
                }
            }
            /****/

            // Get the current leaf's element index
            final QName element = fLeafList[outIndex].getElement();

            // See if the current leaf node's element index is in the list
            int inIndex = 0;
            for (; inIndex < fElemMapSize; inIndex++)
            {
                if (fElemMap[inIndex].rawname == element.rawname) {
                    break;
                }
            }

            // If it was not in the list, then add it, if not the EOC node
            if (inIndex == fElemMapSize) {
                fElemMap[fElemMapSize].setValues(element);
                fElemMapType[fElemMapSize] = fLeafListType[outIndex];
                fElemMapSize++;
            }
        }
        // set up the fLeafNameTypeVector object if there is one.
        /*****
        if (fLeafNameTypeVector != null) {
            fLeafNameTypeVector.setValues(fElemMap, fElemMapType, fElemMapSize);
        }

        /***
        * Optimization(Jan, 2001); We sort fLeafList according to
        * elemIndex which is *uniquely* associated to each leaf.
        * We are *assuming* that each element appears in at least one leaf.
        **/

        int[] fLeafSorter = new int[fLeafCount + fElemMapSize];
        int fSortCount = 0;

        for (int elemIndex = 0; elemIndex < fElemMapSize; elemIndex++) {
            for (int leafIndex = 0; leafIndex < fLeafCount; leafIndex++) {
                    final QName leaf = fLeafList[leafIndex].getElement();
                    final QName element = fElemMap[elemIndex];
                    if (leaf.rawname == element.rawname) {
                            fLeafSorter[fSortCount++] = leafIndex;
                    }
            }
            fLeafSorter[fSortCount++] = -1;
        }

        /* Optimization(Jan, 2001) */

        //
        //  Next lets create some arrays, some that that hold transient
        //  information during the DFA build and some that are permament.
        //  These are kind of sticky since we cannot know how big they will
        //  get, but we don't want to use any Java collections because of
        //  performance.
        //
        //  Basically they will probably be about fLeafCount*2 on average,
        //  but can be as large as 2^(fLeafCount*2), worst case. So we start
        //  with fLeafCount*4 as a middle ground. This will be very unlikely
        //  to ever have to expand, though it if does, the overhead will be
        //  somewhat ugly.
        //
        int curArraySize = fLeafCount * 4;
        CMStateSet[] statesToDo = new CMStateSet[curArraySize];
        fFinalStateFlags = new boolean[curArraySize];
        fTransTable = new int[curArraySize][];

        //
        //  Ok we start with the initial set as the first pos set of the
        //  head node (which is the seq node that holds the content model
        //  and the EOC node.)
        //
        CMStateSet setT = fHeadNode.firstPos();

        //
        //  Init our two state flags. Basically the unmarked state counter
        //  is always chasing the current state counter. When it catches up,
        //  that means we made a pass through that did not add any new states
        //  to the lists, at which time we are done. We could have used a
        //  expanding array of flags which we used to mark off states as we
        //  complete them, but this is easier though less readable maybe.
        //
        int unmarkedState = 0;
        int curState = 0;

        //
        //  Init the first transition table entry, and put the initial state
        //  into the states to do list, then bump the current state.
        //
        fTransTable[curState] = makeDefStateList();
        statesToDo[curState] = setT;
        curState++;

            /* Optimization(Jan, 2001); This is faster for
             * a large content model such as, "(t001+|t002+|.... |t500+)".
             */

        Map<CMStateSet, Integer> stateTable = new HashMap<>();

            /* Optimization(Jan, 2001) */

        //
        //  Ok, almost done with the algorithm... We now enter the
        //  loop where we go until the states done counter catches up with
        //  the states to do counter.
        //
        while (unmarkedState < curState)
        {
            //
            //  Get the first unmarked state out of the list of states to do.
            //  And get the associated transition table entry.
            //
            setT = statesToDo[unmarkedState];
            int[] transEntry = fTransTable[unmarkedState];

            // Mark this one final if it contains the EOC state
            fFinalStateFlags[unmarkedState] = setT.getBit(fEOCPos);

            // Bump up the unmarked state count, marking this state done
            unmarkedState++;

            // Loop through each possible input symbol in the element map
            CMStateSet newSet = null;
            /* Optimization(Jan, 2001) */
            int sorterIndex = 0;
            /* Optimization(Jan, 2001) */
            for (int elemIndex = 0; elemIndex < fElemMapSize; elemIndex++)
            {
                //
                //  Build up a set of states which is the union of all of
                //  the follow sets of DFA positions that are in the current
                //  state. If we gave away the new set last time through then
                //  create a new one. Otherwise, zero out the existing one.
                //
                if (newSet == null)
                    newSet = new CMStateSet(fLeafCount);
                else
                    newSet.zeroBits();

            /* Optimization(Jan, 2001) */
                int leafIndex = fLeafSorter[sorterIndex++];

                while (leafIndex != -1) {
                // If this leaf index (DFA position) is in the current set...
                    if (setT.getBit(leafIndex))
                    {
                        //
                        //  If this leaf is the current input symbol, then we
                        //  want to add its follow list to the set of states to
                        //  transition to from the current state.
                        //
                                newSet.union(fFollowList[leafIndex]);
                            }

                   leafIndex = fLeafSorter[sorterIndex++];
        }
            /* Optimization(Jan, 2001) */

                //
                //  If this new set is not empty, then see if its in the list
                //  of states to do. If not, then add it.
                //
                if (!newSet.isEmpty())
                {
                    //
                    //  Search the 'states to do' list to see if this new
                    //  state set is already in there.
                    //

            /* Optimization(Jan, 2001) */
            Integer stateObj = stateTable.get(newSet);
            int stateIndex = (stateObj == null ? curState : stateObj.intValue());
            /* Optimization(Jan, 2001) */

                    // If we did not find it, then add it
                    if (stateIndex == curState)
                    {
                        //
                        //  Put this new state into the states to do and init
                        //  a new entry at the same index in the transition
                        //  table.
                        //
                        statesToDo[curState] = newSet;
                        fTransTable[curState] = makeDefStateList();

            /* Optimization(Jan, 2001) */
                        stateTable.put(newSet, curState);
            /* Optimization(Jan, 2001) */

                        // We now have a new state to do so bump the count
                        curState++;

                        //
                        //  Null out the new set to indicate we adopted it.
                        //  This will cause the creation of a new set on the
                        //  next time around the loop.
                        //
                        newSet = null;
                    }

                    //
                    //  Now set this state in the transition table's entry
                    //  for this element (using its index), with the DFA
                    //  state we will move to from the current state when we
                    //  see this input element.
                    //
                    transEntry[elemIndex] = stateIndex;

                    // Expand the arrays if we're full
                    if (curState == curArraySize)
                    {
                        //
                        //  Yikes, we overflowed the initial array size, so
                        //  we've got to expand all of these arrays. So adjust
                        //  up the size by 50% and allocate new arrays.
                        //
                        final int newSize = (int)(curArraySize * 1.5);
                        CMStateSet[] newToDo = new CMStateSet[newSize];
                        boolean[] newFinalFlags = new boolean[newSize];
                        int[][] newTransTable = new int[newSize][];

                        // Copy over all of the existing content
                        System.arraycopy(statesToDo, 0, newToDo, 0, curArraySize);
                        System.arraycopy(fFinalStateFlags, 0, newFinalFlags, 0, curArraySize);
                        System.arraycopy(fTransTable, 0, newTransTable, 0, curArraySize);

                        // Store the new array size
                        curArraySize = newSize;
                        statesToDo = newToDo;
                        fFinalStateFlags = newFinalFlags;
                        fTransTable = newTransTable;
                    }
                }
            }
        }

        // Check to see if we can set the fEmptyContentIsValid flag.
        fEmptyContentIsValid = ((CMBinOp)fHeadNode).getLeft().isNullable();

        //
        //  And now we can say bye bye to the temp representation since we've
        //  built the DFA.
        //
        if (DEBUG_VALIDATE_CONTENT)
            dumpTree(fHeadNode, 0);
        fHeadNode = null;
        fLeafList = null;
        fFollowList = null;

    }

    Calculates the follow list of the current node.
Params: nodeCur – The curent node.
Throws: CMException – Thrown if follow list cannot be calculated./**
     * Calculates the follow list of the current node.
     *
     * @param nodeCur The curent node.
     *
     * @exception CMException Thrown if follow list cannot be calculated.
     */
    private void calcFollowList(CMNode nodeCur)
    {
        // Recurse as required
        if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_CHOICE)
        {
            // Recurse only
            calcFollowList(((CMBinOp)nodeCur).getLeft());
            calcFollowList(((CMBinOp)nodeCur).getRight());
        }
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_SEQ)
        {
            // Recurse first
            calcFollowList(((CMBinOp)nodeCur).getLeft());
            calcFollowList(((CMBinOp)nodeCur).getRight());

            //
            //  Now handle our level. We use our left child's last pos
            //  set and our right child's first pos set, so go ahead and
            //  get them ahead of time.
            //
            final CMStateSet last  = ((CMBinOp)nodeCur).getLeft().lastPos();
            final CMStateSet first = ((CMBinOp)nodeCur).getRight().firstPos();

            //
            //  Now, for every position which is in our left child's last set
            //  add all of the states in our right child's first set to the
            //  follow set for that position.
            //
            for (int index = 0; index < fLeafCount; index++)
            {
                if (last.getBit(index))
                    fFollowList[index].union(first);
            }
        }
         /***
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE)
        {
            // Recurse first
            calcFollowList(((CMUniOp)nodeCur).getChild());

            //
            //  Now handle our level. We use our own first and last position
            //  sets, so get them up front.
            //
            final CMStateSet first = nodeCur.firstPos();
            final CMStateSet last  = nodeCur.lastPos();

            //
            //  For every position which is in our last position set, add all
            //  of our first position states to the follow set for that
            //  position.
            //
            for (int index = 0; index < fLeafCount; index++)
            {
                if (last.getBit(index))
                    fFollowList[index].union(first);
            }
        }
         else if ((nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE)
              ||  (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE))
        {
            throw new RuntimeException("ImplementationMessages.VAL_NIICM");
        }
        /***/
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE
            || nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE)
        {
            // Recurse first
            calcFollowList(((CMUniOp)nodeCur).getChild());

            //
            //  Now handle our level. We use our own first and last position
            //  sets, so get them up front.
            //
            final CMStateSet first = nodeCur.firstPos();
            final CMStateSet last  = nodeCur.lastPos();

            //
            //  For every position which is in our last position set, add all
            //  of our first position states to the follow set for that
            //  position.
            //
            for (int index = 0; index < fLeafCount; index++)
            {
                if (last.getBit(index))
                    fFollowList[index].union(first);
            }
        }

        else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE) {
            // Recurse only
            calcFollowList(((CMUniOp)nodeCur).getChild());
        }
         /***/
    }

    Dumps the tree of the current node to standard output.
Params: nodeCur – The current node.
level –   The maximum levels to output.
Throws: CMException – Thrown on error./**
     * Dumps the tree of the current node to standard output.
     *
     * @param nodeCur The current node.
     * @param level   The maximum levels to output.
     *
     * @exception CMException Thrown on error.
     */
    private void dumpTree(CMNode nodeCur, int level)
    {
        for (int index = 0; index < level; index++)
            System.out.print("   ");

        int type = nodeCur.type();
        if ((type == XMLContentSpec.CONTENTSPECNODE_CHOICE)
        ||  (type == XMLContentSpec.CONTENTSPECNODE_SEQ))
        {
            if (type == XMLContentSpec.CONTENTSPECNODE_CHOICE)
                System.out.print("Choice Node ");
            else
                System.out.print("Seq Node ");

            if (nodeCur.isNullable())
                System.out.print("Nullable ");

            System.out.print("firstPos=");
            System.out.print(nodeCur.firstPos().toString());
            System.out.print(" lastPos=");
            System.out.println(nodeCur.lastPos().toString());

            dumpTree(((CMBinOp)nodeCur).getLeft(), level+1);
            dumpTree(((CMBinOp)nodeCur).getRight(), level+1);
        }
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE)
        {
            System.out.print("Rep Node ");

            if (nodeCur.isNullable())
                System.out.print("Nullable ");

            System.out.print("firstPos=");
            System.out.print(nodeCur.firstPos().toString());
            System.out.print(" lastPos=");
            System.out.println(nodeCur.lastPos().toString());

            dumpTree(((CMUniOp)nodeCur).getChild(), level+1);
        }
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_LEAF)
        {
            System.out.print
            (
                "Leaf: (pos="
                + ((CMLeaf)nodeCur).getPosition()
                + "), "
                + ((CMLeaf)nodeCur).getElement()
                + "(elemIndex="
                + ((CMLeaf)nodeCur).getElement()
                + ") "
            );

            if (nodeCur.isNullable())
                System.out.print(" Nullable ");

            System.out.print("firstPos=");
            System.out.print(nodeCur.firstPos().toString());
            System.out.print(" lastPos=");
            System.out.println(nodeCur.lastPos().toString());
        }
         else
        {
            throw new RuntimeException("ImplementationMessages.VAL_NIICM");
        }
    }


    -1 is used to represent bad transitions in the transition table
entry for each state. So each entry is initialized to an all -1
array. This method creates a new entry and initializes it.
/**
     * -1 is used to represent bad transitions in the transition table
     * entry for each state. So each entry is initialized to an all -1
     * array. This method creates a new entry and initializes it.
     */
    private int[] makeDefStateList()
    {
        int[] retArray = new int[fElemMapSize];
        for (int index = 0; index < fElemMapSize; index++)
            retArray[index] = -1;
        return retArray;
    }

    Post tree build initialization. /** Post tree build initialization. */
    private int postTreeBuildInit(CMNode nodeCur, int curIndex)
    {
        // Set the maximum states on this node
        nodeCur.setMaxStates(fLeafCount);

        // Recurse as required
        if ((nodeCur.type() & 0x0f) == XMLContentSpec.CONTENTSPECNODE_ANY ||
            (nodeCur.type() & 0x0f) == XMLContentSpec.CONTENTSPECNODE_ANY_LOCAL ||
            (nodeCur.type() & 0x0f) == XMLContentSpec.CONTENTSPECNODE_ANY_OTHER) {
            // REVISIT: Don't waste these structures.
            QName qname = new QName(null, null, null, ((CMAny)nodeCur).getURI());
            fLeafList[curIndex] = new CMLeaf(qname, ((CMAny)nodeCur).getPosition());
            fLeafListType[curIndex] = nodeCur.type();
            curIndex++;
        }
        else if ((nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_CHOICE)
        ||  (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_SEQ))
        {
            curIndex = postTreeBuildInit(((CMBinOp)nodeCur).getLeft(), curIndex);
            curIndex = postTreeBuildInit(((CMBinOp)nodeCur).getRight(), curIndex);
        }
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE
             || nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE
             || nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE)
        {
            curIndex = postTreeBuildInit(((CMUniOp)nodeCur).getChild(), curIndex);
        }
         else if (nodeCur.type() == XMLContentSpec.CONTENTSPECNODE_LEAF)
        {
            //
            //  Put this node in the leaf list at the current index if its
            //  a non-epsilon leaf.
            //
             final QName node = ((CMLeaf)nodeCur).getElement();
            if (node.localpart != fEpsilonString) {
                fLeafList[curIndex] = (CMLeaf)nodeCur;
                fLeafListType[curIndex] = XMLContentSpec.CONTENTSPECNODE_LEAF;
                curIndex++;
            }
        }
         else
        {
            throw new RuntimeException("ImplementationMessages.VAL_NIICM: type="+nodeCur.type());
        }
        return curIndex;
    }

} // class DFAContentModel
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.
Params:	syntaxTree – The syntax tree.
Throws:	CMException – Thrown if DFA cannot be built.
Params:	nodeCur – The curent node.
Throws:	CMException – Thrown if follow list cannot be calculated.
Params:	nodeCur – The current node. level – The maximum levels to output.
Throws:	CMException – Thrown on error.
/

java/ 15/ java.xml/com/sun/org/apache/xerces/internal/impl/dtd/models/DFAContentModel.java
