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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
*   Copyright (c) 2002-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*/

package com.ibm.icu.text;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;

import com.ibm.icu.impl.Assert;
import com.ibm.icu.impl.RBBIDataWrapper;
import com.ibm.icu.lang.UCharacter;
import com.ibm.icu.lang.UProperty;
import com.ibm.icu.text.RBBIRuleBuilder.IntPair;

/**
 *  This class is part of the RBBI rule compiler.
 *  It builds the state transition table used by the RBBI runtime
 *  from the expression syntax tree generated by the rule scanner.
 *
 *  This class is part of the RBBI implementation only.
 *  There is no user-visible public API here.
 */
class RBBITableBuilder {

    //
    //  RBBIStateDescriptor - The DFA is initially constructed as a set of these descriptors,
    //                        one for each state.
    static class RBBIStateDescriptor {
        boolean      fMarked;
        int          fAccepting;
        int          fLookAhead;
        SortedSet fTagVals;
        int          fTagsIdx;
        Set fPositions;                 // Set of parse tree positions associated
                                                  //   with this state.  Unordered (it's a set).
                                                  //   UVector contents are RBBINode *

        int[]        fDtran;                      // Transitions out of this state.
                                                   //   indexed by input character
                                                   //   contents is int index of dest state
                                                   //   in RBBITableBuilder.fDStates

        RBBIStateDescriptor(int maxInputSymbol) {
            fTagVals = new TreeSet<>();
            fPositions = new HashSet<>();
            fDtran = new int[maxInputSymbol+1];    // fDtran needs to be pre-sized.
                                                    //   It is indexed by input symbols, and will
                                                    //   hold  the next state number for each
                                                    //   symbol.
        }
    }


    private  RBBIRuleBuilder  fRB;

    /** The array index into RBBIRuleBuilder.fTreeRoots for the parse tree to operate on. */
    private  int  fRootIx;

    /** D states (Aho's terminology). Index is state number. */
    private  List fDStates;

    /** Synthesized safe table, a List of row arrays.  */
    private List    fSafeTable;

    private static final int MAX_STATE_FOR_8BITS_TABLE = 255;

    /** Map from rule number (fVal in look ahead nodes) to sequential lookahead index. */
    int[] fLookAheadRuleMap;

    /** Counter used when assigning lookahead rule numbers.
     * Contains the last look-ahead number already in use.
     * The first look-ahead number is 2; Number 1 (ACCEPTING_UNCONDITIONAL) is reserved
     * for non-lookahead accepting states. See the declarations of RBBIStateTableRowT.   */
    int  fLASlotsInUse = RBBIDataWrapper.ACCEPTING_UNCONDITIONAL;

    //-----------------------------------------------------------------------------
    //
    //  Constructor    for RBBITableBuilder.
    //
    //                 rootNode is an index into the array of root nodes that is held by
    //                          the overall RBBIRuleBuilder.
    //-----------------------------------------------------------------------------
    RBBITableBuilder(RBBIRuleBuilder rb,  int rootNodeIx)  {
           fRootIx     = rootNodeIx;
           fRB         = rb;
           fDStates    = new ArrayList<>();
        }




       //-----------------------------------------------------------------------------
       //
       //   RBBITableBuilder::buildForwardTable  -  This is the main function for building
       //                          the DFA state transition table from the RBBI rules parse tree.
       //
       //-----------------------------------------------------------------------------
       void  buildForwardTable() {
           // If there were no rules, just return.  This situation can easily arise
           //   for the reverse rules.
           if (fRB.fTreeRoots[fRootIx]==null) {
               return;
           }

           //
           // Walk through the tree, replacing any references to $variables with a copy of the
           //   parse tree for the substitution expression.
           //
           fRB.fTreeRoots[fRootIx] = fRB.fTreeRoots[fRootIx].flattenVariables();
           if (fRB.fDebugEnv!=null && fRB.fDebugEnv.indexOf("ftree")>=0) {
               System.out.println("Parse tree after flattening variable references.");
               fRB.fTreeRoots[fRootIx].printTree(true);
           }

           //
           // If the rules contained any references to {bof}
           //   add a {bof}   to the
           //   tree.  Means that all matches must start out with the
           //   {bof} fake character.
           //
           if (fRB.fSetBuilder.sawBOF()) {
               RBBINode bofTop    = new RBBINode(RBBINode.opCat);
               RBBINode bofLeaf   = new RBBINode(RBBINode.leafChar);
               bofTop.fLeftChild  = bofLeaf;
               bofTop.fRightChild = fRB.fTreeRoots[fRootIx];
               bofLeaf.fParent    = bofTop;
               bofLeaf.fVal       = 2;      // Reserved value for {bof}.
               fRB.fTreeRoots[fRootIx] = bofTop;
           }

           //
           // Add a unique right-end marker to the expression.
           //   Appears as a cat-node, left child being the original tree,
           //   right child being the end marker.
           //
           RBBINode cn = new RBBINode(RBBINode.opCat);
           cn.fLeftChild = fRB.fTreeRoots[fRootIx];
           fRB.fTreeRoots[fRootIx].fParent = cn;
           RBBINode endMarkerNode = cn.fRightChild = new RBBINode(RBBINode.endMark);
           cn.fRightChild.fParent = cn;
           fRB.fTreeRoots[fRootIx] = cn;

           //
           //  Replace all references to UnicodeSets with the tree for the equivalent
           //      expression.
           //
           fRB.fTreeRoots[fRootIx].flattenSets();
           if (fRB.fDebugEnv!=null && fRB.fDebugEnv.indexOf("stree")>=0) {
               System.out.println("Parse tree after flattening Unicode Set references.");
               fRB.fTreeRoots[fRootIx].printTree(true);
           }


           //
           // calculate the functions nullable, firstpos, lastpos and followpos on
           // nodes in the parse tree.
           //    See the algorithm description in Aho.
           //    Understanding how this works by looking at the code alone will be
           //       nearly impossible.
           //
           calcNullable(fRB.fTreeRoots[fRootIx]);
           calcFirstPos(fRB.fTreeRoots[fRootIx]);
           calcLastPos(fRB.fTreeRoots[fRootIx]);
           calcFollowPos(fRB.fTreeRoots[fRootIx]);
           if (fRB.fDebugEnv!=null && fRB.fDebugEnv.indexOf("pos")>=0) {
               System.out.print("\n");
               printPosSets(fRB.fTreeRoots[fRootIx]);
           }

           //
           //  For "chained" rules, modify the followPos sets
           //
           if (fRB.fChainRules) {
               calcChainedFollowPos(fRB.fTreeRoots[fRootIx], endMarkerNode);
           }

           //
           //  BOF (start of input) test fixup.
           //
           if (fRB.fSetBuilder.sawBOF()) {
               bofFixup();
           }

           //
           // Build the DFA state transition tables.
           //
           buildStateTable();
           mapLookAheadRules();
           flagAcceptingStates();
           flagLookAheadStates();
           flagTaggedStates();

           //
           // Update the global table of rule status {tag} values
           // The rule builder has a global vector of status values that are common
           //    for all tables.  Merge the ones from this table into the global set.
           //
           mergeRuleStatusVals();
       }



       //-----------------------------------------------------------------------------
       //
       //   calcNullable.    Impossible to explain succinctly.  See Aho, section 3.9
       //
       //-----------------------------------------------------------------------------
       void calcNullable(RBBINode n) {
           if (n == null) {
               return;
           }
           if (n.fType == RBBINode.setRef ||
               n.fType == RBBINode.endMark ) {
               // These are non-empty leaf node types.
               n.fNullable = false;
               return;
           }

           if (n.fType == RBBINode.lookAhead || n.fType == RBBINode.tag) {
               // Lookahead marker node.  It's a leaf, so no recursion on children.
               // It's nullable because it does not match any literal text from the input stream.
               n.fNullable = true;
               return;
           }


           // The node is not a leaf.
           //  Calculate nullable on its children.
           calcNullable(n.fLeftChild);
           calcNullable(n.fRightChild);

           // Apply functions from table 3.40 in Aho
           if (n.fType == RBBINode.opOr) {
               n.fNullable = n.fLeftChild.fNullable || n.fRightChild.fNullable;
           }
           else if (n.fType == RBBINode.opCat) {
               n.fNullable = n.fLeftChild.fNullable && n.fRightChild.fNullable;
           }
           else if (n.fType == RBBINode.opStar || n.fType == RBBINode.opQuestion) {
               n.fNullable = true;
           }
           else {
               n.fNullable = false;
           }
       }




       //-----------------------------------------------------------------------------
       //
       //   calcFirstPos.    Impossible to explain succinctly.  See Aho, section 3.9
       //
       //-----------------------------------------------------------------------------
       void calcFirstPos(RBBINode n) {
           if (n == null) {
               return;
           }
           if (n.fType == RBBINode.leafChar  ||
               n.fType == RBBINode.endMark   ||
               n.fType == RBBINode.lookAhead ||
               n.fType == RBBINode.tag) {
               // These are non-empty leaf node types.
               n.fFirstPosSet.add(n);
               return;
           }

           // The node is not a leaf.
           //  Calculate firstPos on its children.
           calcFirstPos(n.fLeftChild);
           calcFirstPos(n.fRightChild);

           // Apply functions from table 3.40 in Aho
           if (n.fType == RBBINode.opOr) {
               n.fFirstPosSet.addAll(n.fLeftChild.fFirstPosSet);
               n.fFirstPosSet.addAll(n.fRightChild.fFirstPosSet);
           }
           else if (n.fType == RBBINode.opCat) {
               n.fFirstPosSet.addAll(n.fLeftChild.fFirstPosSet);
               if (n.fLeftChild.fNullable) {
                   n.fFirstPosSet.addAll(n.fRightChild.fFirstPosSet);
               }
           }
           else if (n.fType == RBBINode.opStar ||
                    n.fType == RBBINode.opQuestion ||
                    n.fType == RBBINode.opPlus) {
               n.fFirstPosSet.addAll(n.fLeftChild.fFirstPosSet);
           }
       }



       //-----------------------------------------------------------------------------
       //
       //   calcLastPos.    Impossible to explain succinctly.  See Aho, section 3.9
       //
       //-----------------------------------------------------------------------------
       void calcLastPos(RBBINode n) {
           if (n == null) {
               return;
           }
           if (n.fType == RBBINode.leafChar  ||
               n.fType == RBBINode.endMark   ||
               n.fType == RBBINode.lookAhead ||
               n.fType == RBBINode.tag) {
               // These are non-empty leaf node types.
               n.fLastPosSet.add(n);
               return;
           }

           // The node is not a leaf.
           //  Calculate lastPos on its children.
           calcLastPos(n.fLeftChild);
           calcLastPos(n.fRightChild);

           // Apply functions from table 3.40 in Aho
           if (n.fType == RBBINode.opOr) {
               n.fLastPosSet.addAll(n.fLeftChild.fLastPosSet);
               n.fLastPosSet.addAll(n.fRightChild.fLastPosSet);
           }
           else if (n.fType == RBBINode.opCat) {
               n.fLastPosSet.addAll(n.fRightChild.fLastPosSet);
               if (n.fRightChild.fNullable) {
                   n.fLastPosSet.addAll(n.fLeftChild.fLastPosSet);
               }
           }
           else if (n.fType == RBBINode.opStar     ||
                    n.fType == RBBINode.opQuestion ||
                    n.fType == RBBINode.opPlus) {
               n.fLastPosSet.addAll(n.fLeftChild.fLastPosSet);
           }
       }



       //-----------------------------------------------------------------------------
       //
       //   calcFollowPos.    Impossible to explain succinctly.  See Aho, section 3.9
       //
       //-----------------------------------------------------------------------------
       void calcFollowPos(RBBINode n) {
           if (n == null ||
               n.fType == RBBINode.leafChar ||
               n.fType == RBBINode.endMark) {
               return;
           }

           calcFollowPos(n.fLeftChild);
           calcFollowPos(n.fRightChild);

           // Aho rule #1
           if (n.fType == RBBINode.opCat) {
               for (RBBINode i /* is 'i' in Aho's description */ : n.fLeftChild.fLastPosSet) {
                   i.fFollowPos.addAll(n.fRightChild.fFirstPosSet);
               }
           }

           // Aho rule #2
           if (n.fType == RBBINode.opStar ||
               n.fType == RBBINode.opPlus) {
               for (RBBINode i /* again, n and i are the names from Aho's description */ : n.fLastPosSet) {
                   i.fFollowPos.addAll(n.fFirstPosSet);
               }
           }
       }

       //-----------------------------------------------------------------------------
       //
       //           addRuleRootNodes    Recursively walk a parse tree, adding all nodes flagged
       //                               as roots of a rule to a destination vector.
       //
       //-----------------------------------------------------------------------------
       void addRuleRootNodes(List dest, RBBINode node) {
           if (node == null) {
               return;
           }
           if (node.fRuleRoot) {
               dest.add(node);
               // Note: rules cannot nest. If we found a rule start node,
               //       no child node can also be a start node.
               return;
           }
           addRuleRootNodes(dest, node.fLeftChild);
           addRuleRootNodes(dest, node.fRightChild);
       }

       //-----------------------------------------------------------------------------
       //
       //   calcChainedFollowPos.    Modify the previously calculated followPos sets
       //                            to implement rule chaining.  NOT described by Aho
       //
       //-----------------------------------------------------------------------------
       void calcChainedFollowPos(RBBINode tree, RBBINode endMarkNode) {

           List leafNodes      = new ArrayList<>();

           // get a list all leaf nodes
           tree.findNodes(leafNodes, RBBINode.leafChar);

           // Collect all leaf nodes that can start matches for rules
           // with inbound chaining enabled, which is the union of the
           // firstPosition sets from each of the rule root nodes.

           List ruleRootNodes = new ArrayList<>();
           addRuleRootNodes(ruleRootNodes, tree);

           Set matchStartNodes = new HashSet<>();
           for (RBBINode node: ruleRootNodes) {
               if (node.fChainIn) {
                   matchStartNodes.addAll(node.fFirstPosSet);
               }
           }

           // Iterate over all leaf nodes,
           //
           for (RBBINode endNode : leafNodes) {

               // Identify leaf nodes that correspond to overall rule match positions.
               //   These include the endMarkNode in their followPos sets.
               //
               // Note: do not consider other end marker nodes, those that are added to
               //       look-ahead rules. These can't chain; a match immediately stops
               //       further matching. This leaves exactly one end marker node, the one
               //       at the end of the complete tree.

               if (!endNode.fFollowPos.contains(endMarkNode)) {
                   continue;
               }

               // We've got a node that can end a match.

               // !!LBCMNoChain implementation:  If this node's val correspond to
               // the Line Break $CM char class, don't chain from it.
               // TODO:  Remove this. !!LBCMNoChain is deprecated, and is not used
               //             by any of the standard ICU rules.
               if (fRB.fLBCMNoChain) {
                   int c = this.fRB.fSetBuilder.getFirstChar(endNode.fVal);
                   if (c != -1) {
                       // c == -1 occurs with sets containing only the {eof} marker string.
                       int cLBProp = UCharacter.getIntPropertyValue(c, UProperty.LINE_BREAK);
                       if (cLBProp == UCharacter.LineBreak.COMBINING_MARK) {
                           continue;
                       }
                   }
               }


               // Now iterate over the nodes that can start a match, looking for ones
               //   with the same char class as our ending node.
               for (RBBINode startNode : matchStartNodes) {
                   if (startNode.fType != RBBINode.leafChar) {
                       continue;
                   }

                   if (endNode.fVal == startNode.fVal) {
                       // The end val (character class) of one possible match is the
                       //   same as the start of another.

                       // Add all nodes from the followPos of the start node to the
                       //  followPos set of the end node, which will have the effect of
                       //  letting matches transition from a match state at endNode
                       //  to the second char of a match starting with startNode.
                       endNode.fFollowPos.addAll(startNode.fFollowPos);
                   }
               }
           }
       }


       //-----------------------------------------------------------------------------
       //
       //   bofFixup.    Fixup for state tables that include {bof} beginning of input testing.
       //                Do an swizzle similar to chaining, modifying the followPos set of
       //                the bofNode to include the followPos nodes from other {bot} nodes
       //                scattered through the tree.
       //
       //                This function has much in common with calcChainedFollowPos().
       //
       //-----------------------------------------------------------------------------
       void bofFixup() {
           //
           //   The parse tree looks like this ...
           //         fTree root  --.       
           //                               /     \
           //                               <#end node>
           //                           /     \
           //                        rest
           //                               of tree
           //
           //    We will be adding things to the followPos set of the 
           //
           RBBINode  bofNode = fRB.fTreeRoots[fRootIx].fLeftChild.fLeftChild;
           Assert.assrt(bofNode.fType == RBBINode.leafChar);
           Assert.assrt(bofNode.fVal == 2);

           // Get all nodes that can be the start a match of the user-written rules
           //  (excluding the fake bofNode)
           //  We want the nodes that can start a match in the
           //     part labeled "rest of tree"
           //
           Set matchStartNodes = fRB.fTreeRoots[fRootIx].fLeftChild.fRightChild.fFirstPosSet;
           for (RBBINode startNode : matchStartNodes) {
               if (startNode.fType != RBBINode.leafChar) {
                   continue;
               }

               if (startNode.fVal == bofNode.fVal) {
                   //  We found a leaf node corresponding to a {bof} that was
                   //    explicitly written into a rule.
                   //  Add everything from the followPos set of this node to the
                   //    followPos set of the fake bofNode at the start of the tree.
                   //
                   bofNode.fFollowPos.addAll(startNode.fFollowPos);
               }
           }
       }

       //-----------------------------------------------------------------------------
       //
       //   buildStateTable()    Determine the set of runtime DFA states and the
       //                        transition tables for these states, by the algorithm
       //                        of fig. 3.44 in Aho.
       //
       //                        Most of the comments are quotes of Aho's psuedo-code.
       //
       //-----------------------------------------------------------------------------
       void buildStateTable() {
           //
           // Add a dummy state 0 - the stop state.  Not from Aho.
           int      lastInputSymbol = fRB.fSetBuilder.getNumCharCategories() - 1;
           RBBIStateDescriptor failState = new RBBIStateDescriptor(lastInputSymbol);
           fDStates.add(failState);

           // initially, the only unmarked state in Dstates is firstpos(root),
           //       where toot is the root of the syntax tree for (r)#;
           RBBIStateDescriptor initialState = new RBBIStateDescriptor(lastInputSymbol);
           initialState.fPositions.addAll(fRB.fTreeRoots[fRootIx].fFirstPosSet);
           fDStates.add(initialState);

           // while there is an unmarked state T in Dstates do begin
           for (;;) {
               RBBIStateDescriptor T = null;
               int              tx;
               for (tx=1; tx U = null;
                   for (RBBINode p : T.fPositions) {
                       if ((p.fType == RBBINode.leafChar) &&  (p.fVal == a)) {
                           if (U == null) {
                               U = new HashSet<>();
                           }
                           U.addAll(p.fFollowPos);
                       }
                   }

                   // if U is not empty and not in DStates then
                   int  ux = 0;
                   boolean    UinDstates = false;
                   if (U != null) {
                       Assert.assrt(U.size() > 0);
                       int  ix;
                       for (ix=0; ix 0);
                  int laSlot = fLookAheadRuleMap[ruleNum];
                  if (laSlot != 0) {
                      if (laSlotForState == 0) {
                          laSlotForState = laSlot;
                      } else {
                          // TODO: figure out if this can fail, change to setting an error code if so.
                          assert(laSlot == laSlotForState);
                      }
                  }
              }
              if (!sawLookAheadNode) {
                  continue;
              }

              if (laSlotForState == 0) {
                  laSlotForState = ++fLASlotsInUse;
              }

              // For each look ahead node covered by this state,
              // set the mapping from the node's rule number to the look ahead slot.
              // There can be multiple nodes/rule numbers going to the same la slot.

              for (RBBINode node: sd.fPositions) {
                  if (node.fType != RBBINode.lookAhead) {
                      continue;
                  }
                  int ruleNum = node.fVal;     // Set when rule was originally parsed.
                  int existingVal = fLookAheadRuleMap[ruleNum];
                  assert(existingVal == 0 || existingVal == laSlotForState);
                  fLookAheadRuleMap[ruleNum] = laSlotForState;
              }
          }

      }

       //-----------------------------------------------------------------------------
       //
       //   flagAcceptingStates    Identify accepting states.
       //                          First get a list of all of the end marker nodes.
       //                          Then, for each state s,
       //                              if s contains one of the end marker nodes in its list of tree positions then
       //                                  s is an accepting state.
       //
       //-----------------------------------------------------------------------------
       void     flagAcceptingStates() {
           List endMarkerNodes = new ArrayList<>();
           RBBINode    endMarker;
           int     i;
           int     n;

           fRB.fTreeRoots[fRootIx].findNodes(endMarkerNodes, RBBINode.endMark);

           for (i=0; i lookAheadNodes = new ArrayList<>();
           RBBINode    lookAheadNode;
           int     i;
           int     n;

           fRB.fTreeRoots[fRootIx].findNodes(lookAheadNodes, RBBINode.lookAhead);
           for (i=0; i tagNodes = new ArrayList<>();
           RBBINode    tagNode;
           int     i;
           int     n;

           fRB.fTreeRoots[fRootIx].findNodes(tagNodes, RBBINode.tag);
           for (i=0; i s0 = new TreeSet<>();        // mapping for rules with no explicit tagging
               fRB.fStatusSets.put(s0, Integer.valueOf(0));    //   (key is an empty set).

               SortedSet s1 = new TreeSet<>();        // mapping for rules with explicit tagging of {0}
               s1.add(Integer.valueOf(0));
               fRB.fStatusSets.put(s1, Integer.valueOf(0));
           }

           //    For each state, check whether the state's status tag values are
           //       already entered into the status values array, and add them if not.
           for (n=0; n statusVals = sd.fTagVals;
               Integer arrayIndexI = fRB.fStatusSets.get(statusVals);
               if (arrayIndexI == null) {
                   // This is the first encounter of this set of status values.
                   //   Add them to the statusSets map, This map associates
                   //   the set of status values with an index in the runtime status
                   //   values array.
                   arrayIndexI = Integer.valueOf(fRB.fRuleStatusVals.size());
                   fRB.fStatusSets.put(statusVals, arrayIndexI);

                   // Add the new set of status values to the vector of values that
                   //   will eventually become the array used by the runtime engine.
                   fRB.fRuleStatusVals.add(Integer.valueOf(statusVals.size()));
                   fRB.fRuleStatusVals.addAll(statusVals);
               }

               // Save the runtime array index back into the state descriptor.
               sd.fTagsIdx = arrayIndexI.intValue();
           }
       }







       //-----------------------------------------------------------------------------
       //
       //  printPosSets   Debug function.  Dump Nullable, firstpos, lastpos and followpos
       //                 for each node in the tree.
       //
       //-----------------------------------------------------------------------------

       void printPosSets(RBBINode n) {
           if (n==null) {
               return;
           }
           RBBINode.printNode(n);
           System.out.print("         Nullable:  " + n.fNullable);

           System.out.print("         firstpos:  ");
           printSet(n.fFirstPosSet);

           System.out.print("         lastpos:   ");
           printSet(n.fLastPosSet);

           System.out.print("         followpos: ");
           printSet(n.fFollowPos);

           printPosSets(n.fLeftChild);
           printPosSets(n.fRightChild);
       }



       /**
        *  Find duplicate (redundant) character classes. Begin looking with categories.first.
        *  Duplicates, if found are returned in the categories parameter.
        *  This is an iterator-like function, used to identify character classes
        *  (state table columns) that can be eliminated.
        *  @param categories in/out parameter, specifies where to start looking for duplicates,
        *                and returns the first pair of duplicates found, if any.
        *  @return true if duplicate char classes were found, false otherwise.
        *  @internal
        */
       boolean findDuplCharClassFrom(RBBIRuleBuilder.IntPair categories) {
           int numStates = fDStates.size();
           int numCols = fRB.fSetBuilder.getNumCharCategories();

           int table_base = 0;
           int table_dupl = 0;
           for (; categories.first < numCols-1; ++categories.first) {
               // Note: dictionary & non-dictionary columns cannot be merged.
               //       The limitSecond value prevents considering mixed pairs.
               //       Dictionary categories are >= DictCategoriesStart.
               //       Non dict categories are   <  DictCategoriesStart.
               int limitSecond = categories.first < fRB.fSetBuilder.getDictCategoriesStart() ?
                   fRB.fSetBuilder.getDictCategoriesStart() : numCols;
               for (categories.second=categories.first+1; categories.second < limitSecond; ++categories.second) {
                   for (int state=0; state duplState) {
                       newVal = existingVal - 1;
                   }
                   sd.fDtran[col] = newVal;
               }
           }
       }

       /**
        * Remove a duplicate state from the safe table.
        * @param duplStates The duplicate pair of states.  The first is kept, the second is removed.
        *                   All references to the second in the state table are retargeted
        *                   to the first.
        * @internal
        */
       void removeSafeState(IntPair duplStates) {
           final int keepState = duplStates.first;
           final int duplState = duplStates.second;
           assert(keepState < duplState);
           assert(duplState < fSafeTable.size());

           fSafeTable.remove(duplState);
           int numStates = fSafeTable.size();
           for (int state=0; state duplState) {
                       newVal = existingVal - 1;
                   }
                   row[col] = (short)newVal;
               }
           }
       }


       /**
        *  Check for, and remove duplicate states (table rows).
        *  @return the number of states removed.
        *  @internal
        */
       int removeDuplicateStates() {
           IntPair dupls = new IntPair(3, 0);
           int numStatesRemoved = 0;

           while (findDuplicateState(dupls)) {
               // System.out.printf("Removing duplicate states (%d, %d)\n", dupls.first, dupls.second);
               removeState(dupls);
               ++numStatesRemoved;
           }
           return numStatesRemoved;
       }


       /**
        *  Calculate the size in bytes of the serialized form of this state transition table,
        *  which is identical to the ICU4C runtime form.
        *  Refer to common/rbbidata.h from ICU4C for the declarations of the structures
        *  being matched by this calculation.
        */
       int  getTableSize()  {
           if (fRB.fTreeRoots[fRootIx] == null) {
               return 0;
           }
           int size    = RBBIDataWrapper.RBBIStateTable.fHeaderSize;    // The header, with no rows to the table.
           int numRows = fDStates.size();
           int numCols = fRB.fSetBuilder.getNumCharCategories();
           boolean use8Bits = numRows <= MAX_STATE_FOR_8BITS_TABLE;
           int rowSize = (use8Bits ? 1 : 2 ) * (RBBIDataWrapper.NEXTSTATES + numCols);
           size   += numRows * rowSize;
           size = (size + 7) & ~7;   // round up to a multiple of 8 bytes
           return size;
       }



       /**
        * Create a RBBIDataWrapper.RBBIStateTable for a newly compiled table.
        * RBBIDataWrapper.RBBIStateTable is similar to struct RBBIStateTable in ICU4C,
        * in common/rbbidata.h
        */
       RBBIDataWrapper.RBBIStateTable exportTable() {
           int                state;
           int                col;

           RBBIDataWrapper.RBBIStateTable table = new RBBIDataWrapper.RBBIStateTable();
           if (fRB.fTreeRoots[fRootIx] == null) {
               return table;
           }

           Assert.assrt(fRB.fSetBuilder.getNumCharCategories() < 0x7fff &&
               fDStates.size() < 0x7fff);
           table.fNumStates = fDStates.size();
           table.fDictCategoriesStart = fRB.fSetBuilder.getDictCategoriesStart();
           table.fLookAheadResultsSize =
                   fLASlotsInUse == RBBIDataWrapper.ACCEPTING_UNCONDITIONAL ? 0 : fLASlotsInUse + 1;
           boolean use8Bits = table.fNumStates <= MAX_STATE_FOR_8BITS_TABLE;

           // Size of table size in shorts.
           int rowLen = RBBIDataWrapper.NEXTSTATES + fRB.fSetBuilder.getNumCharCategories();   // Row Length in shorts.
           int tableSize;
           if (use8Bits) {
               tableSize = (getTableSize() - RBBIDataWrapper.RBBIStateTable.fHeaderSize);       // fTable length in bytes.
               table.fTable = new char[tableSize];
               table.fRowLen = rowLen;                          // Row length in bytes.
           } else {
               tableSize = (getTableSize() - RBBIDataWrapper.RBBIStateTable.fHeaderSize) / 2;   // fTable length in shorts.
               table.fTable = new char[tableSize];
               table.fRowLen = rowLen * 2;                      // Row length in bytes.
           }

           if (fRB.fLookAheadHardBreak) {
               table.fFlags  |= RBBIDataWrapper.RBBI_LOOKAHEAD_HARD_BREAK;
           }
           if (fRB.fSetBuilder.sawBOF()) {
               table.fFlags  |= RBBIDataWrapper.RBBI_BOF_REQUIRED;
           }
           if (use8Bits) {
               table.fFlags  |= RBBIDataWrapper.RBBI_8BITS_ROWS;
           }

           int numCharCategories = fRB.fSetBuilder.getNumCharCategories();
           for (state=0; state
           // Row 0 is the stop state.
           // Row 1 is the start sate.
           // Row 2 and beyond are other states, initially one per char class, but
           //   after initial construction, many of the states will be combined, compacting the table.)
           // The String holds the nextState data only. The four leading fields of a row, fAccepting,
           // fLookAhead, etc. are not needed for the safe table, and are omitted at this stage of building.

           assert(fSafeTable == null);
           fSafeTable = new ArrayList<>();
           for (int row=0; row s) {
           for (RBBINode n : s) {
               RBBINode.printInt(n.fSerialNum, 8);
           }
           System.out.println();
       }



       //-----------------------------------------------------------------------------
       //
       //   printStates    Debug Function.  Dump the fully constructed state transition table.
       //
       //-----------------------------------------------------------------------------

       void printStates() {
           int     c;    // input "character"
           int     n;    // state number

           System.out.print("state |           i n p u t     s y m b o l s \n");
           System.out.print("      | Acc  LA    Tag");
           for (c=0; c tbl = fRB.fRuleStatusVals;

           System.out.print("index |  tags \n");
           System.out.print("-------------------\n");

           while (nextRecord < tbl.size()) {
               thisRecord = nextRecord;
               nextRecord = thisRecord + tbl.get(thisRecord).intValue() + 1;
               RBBINode.printInt(thisRecord, 7);
               for (i=thisRecord+1; i




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