initial commit, 4.5 stable

thirdparty/icu4c/common/rbbitblb.h

@@ -0,0 +1,232 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+//
+//  rbbitblb.h
+//
+
+/*
+**********************************************************************
+*   Copyright (c) 2002-2016, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*/
+
+#ifndef RBBITBLB_H
+#define RBBITBLB_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_BREAK_ITERATION
+
+#include "unicode/uobject.h"
+#include "unicode/rbbi.h"
+#include "rbbidata.h"
+#include "rbbirb.h"
+#include "rbbinode.h"
+
+
+U_NAMESPACE_BEGIN
+
+class RBBIRuleScanner;
+class RBBIRuleBuilder;
+class UVector32;
+
+//
+//  class RBBITableBuilder 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 : public UMemory {
+public:
+    RBBITableBuilder(RBBIRuleBuilder *rb, RBBINode **rootNode, UErrorCode &status);
+    ~RBBITableBuilder();
+
+    void     buildForwardTable();
+
+    /** Return the runtime size in bytes of the built state table.  */
+    int32_t  getTableSize() const;
+
+    /** Fill in the runtime state table. Sufficient memory must exist at the specified location.
+     */
+    void     exportTable(void *where);
+
+    /** Use 8 bits to encode the forward table */
+    bool     use8BitsForTable() const;
+
+    /**
+     *  Find duplicate (redundant) character classes. Begin looking with categories.first.
+     *  Duplicate, 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.
+     */
+    bool     findDuplCharClassFrom(IntPair *categories);
+
+    /** Remove a column from the state table. Used when two character categories
+     *  have been found equivalent, and merged together, to eliminate the unneeded table column.
+     */
+    void     removeColumn(int32_t column);
+
+    /**
+     * Check for, and remove duplicate states (table rows).
+     * @return the number of states removed.
+     */
+    int32_t  removeDuplicateStates();
+
+    /** Build the safe reverse table from the already-constructed forward table. */
+    void     buildSafeReverseTable(UErrorCode &status);
+
+    /** Return the runtime size in bytes of the built safe reverse state table. */
+    int32_t  getSafeTableSize() const;
+
+    /** Fill in the runtime safe state table. Sufficient memory must exist at the specified location.
+     */
+    void     exportSafeTable(void *where);
+
+    /** Use 8 bits to encode the safe reverse table */
+    bool     use8BitsForSafeTable() const;
+
+private:
+    void     calcNullable(RBBINode *n);
+    void     calcFirstPos(RBBINode *n);
+    void     calcLastPos(RBBINode  *n);
+    void     calcFollowPos(RBBINode *n);
+    void     calcChainedFollowPos(RBBINode *n, RBBINode *endMarkNode);
+    void     bofFixup();
+    void     buildStateTable();
+    void     mapLookAheadRules();
+    void     flagAcceptingStates();
+    void     flagLookAheadStates();
+    void     flagTaggedStates();
+    void     mergeRuleStatusVals();
+
+    /**
+     * Merge redundant state table columns, eliminating character classes with identical behavior.
+     * Done after the state tables are generated, just before converting to their run-time format.
+     */
+    int32_t  mergeColumns();
+
+    void     addRuleRootNodes(UVector *dest, RBBINode *node);
+
+    /**
+     *  Find duplicate (redundant) states, beginning at the specified pair,
+     *  within this state table. This is an iterator-like function, used to
+     *  identify states (state table rows) that can be eliminated.
+     *  @param states in/out parameter, specifies where to start looking for duplicates,
+     *                and returns the first pair of duplicates found, if any.
+     *  @return true if duplicate states were found, false otherwise.
+     */
+    bool findDuplicateState(IntPair *states);
+
+    /** Remove a duplicate state.
+     * @param duplStates The duplicate states. The first is kept, the second is removed.
+     *                   All references to the second in the state table are retargeted
+     *                   to the first.
+     */
+    void removeState(IntPair duplStates);
+
+    /** Find the next duplicate state in the safe reverse table. An iterator function.
+     *  @param states in/out parameter, specifies where to start looking for duplicates,
+     *                and returns the first pair of duplicates found, if any.
+     *  @return true if a duplicate pair of states was found.
+     */
+    bool findDuplicateSafeState(IntPair *states);
+
+    /** Remove a duplicate state from the safe table.
+     * @param duplStates The duplicate states. The first is kept, the second is removed.
+     *                   All references to the second in the state table are retargeted
+     *                   to the first.
+     */
+    void removeSafeState(IntPair duplStates);
+
+    // Set functions for UVector.
+    //   TODO:  make a USet subclass of UVector
+
+    void     setAdd(UVector *dest, UVector *source);
+    UBool    setEquals(UVector *a, UVector *b);
+
+    void     sortedAdd(UVector **dest, int32_t val);
+
+public:
+#ifdef RBBI_DEBUG
+    void     printSet(UVector *s);
+    void     printPosSets(RBBINode *n /* = nullptr */);
+    void     printStates();
+    void     printRuleStatusTable();
+    void     printReverseTable();
+#else
+    #define  printSet(s)
+    #define  printPosSets(n)
+    #define  printStates()
+    #define  printRuleStatusTable()
+    #define  printReverseTable()
+#endif
+
+private:
+    RBBIRuleBuilder  *fRB;
+    RBBINode         *&fTree;              // The root node of the parse tree to build a
+                                           //   table for.
+    UErrorCode       *fStatus;
+
+    /** State Descriptors, UVector<RBBIStateDescriptor> */
+    UVector          *fDStates;            //  D states (Aho's terminology)
+                                           //  Index is state number
+                                           //  Contents are RBBIStateDescriptor pointers.
+
+    /** Synthesized safe table, UVector of UnicodeString, one string per table row.   */
+    UVector          *fSafeTable;
+
+    /** Map from rule number (fVal in look ahead nodes) to sequential lookahead index. */
+    UVector32        *fLookAheadRuleMap = nullptr;
+
+    /* 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.   */
+    int32_t          fLASlotsInUse = ACCEPTING_UNCONDITIONAL;
+
+
+    RBBITableBuilder(const RBBITableBuilder &other) = delete; // forbid copying of this class
+    RBBITableBuilder &operator=(const RBBITableBuilder &other) = delete; // forbid copying of this class
+};
+
+//
+//  RBBIStateDescriptor - The DFA is constructed as a set of these descriptors,
+//                        one for each state.
+class RBBIStateDescriptor : public UMemory {
+public:
+    UBool            fMarked;
+    uint32_t         fAccepting;
+    uint32_t         fLookAhead;
+    UVector          *fTagVals;
+    int32_t          fTagsIdx;
+    UVector          *fPositions;          // Set of parse tree positions associated
+                                           //   with this state.  Unordered (it's a set).
+                                           //   UVector contents are RBBINode *
+
+    UVector32        *fDtran;              // Transitions out of this state.
+                                           //   indexed by input character
+                                           //   contents is int index of dest state
+                                           //   in RBBITableBuilder.fDStates
+
+    RBBIStateDescriptor(int maxInputSymbol,  UErrorCode *fStatus);
+    ~RBBIStateDescriptor();
+
+private:
+    RBBIStateDescriptor(const RBBIStateDescriptor &other) = delete; // forbid copying of this class
+    RBBIStateDescriptor &operator=(const RBBIStateDescriptor &other) = delete; // forbid copying of this class
+};
+
+
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_BREAK_ITERATION */
+
+#endif