UT/UT_HashTable.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 * 
 * Produced by:
 *      Side Effects Software Inc
 *      477 Richmond Street West
 *      Toronto, Ontario
 *      Canada   M5V 3E7
 *      416-504-9876
 *
 * NAME:        UT_HashTable.h
 *
 * COMMENTS:
 */

#ifndef __UT_HashTable_h__
#define __UT_HashTable_h__

#include "UT_API.h"
#include <stdio.h>
#include <iostream.h>
#include <SYS/SYS_Types.h>
#include "UT_ThingList.h"
#include "UT_Hash.h"

class UT_API UT_HashTable {
public:
    explicit UT_HashTable();
    virtual ~UT_HashTable();

    // Set this to true before adding any items to the hash table if your
    // hash function implements a proper strcmp() (returning -1 for <, 0 for =
    // and 1 for >). This can shorten adds and queries to buckets with more
    // than 1 entry.
    void         useOrderedLists(bool ordered);

    void         addSymbol(const UT_Hash& symbol, const UT_Thing &data);
    int          findSymbol(const UT_Hash& symbol, UT_Thing *datap,
                            const UT_Hash **hash_symbol = 0) const;

    int          contains(const UT_Hash &symbol) const
    { UT_Thing value; return findSymbol(symbol, &value); }

    template <typename T>
    T           *findPointer(const UT_Hash &symbol) const
    {
        UT_Thing thing;
        if (!findSymbol(symbol, &thing))
            return NULL;
        return thing.template asPointer<T>();
    }

    int          deleteSymbol(const UT_Hash& symbol);
    int          moveSymbol(const UT_Hash &oldsymbol,
                            const UT_Hash &newsymbol);
    void         clear();

    unsigned     entries() const { return myNbrEntries; }
    bool         empty() const { return !myNbrEntries; }

    // Retrieve an entry in the table, creating it if it doesn't already exist.
    UT_Thing    &operator[](const UT_Hash& symbol);

    // The table will automatically rebuild itself to keep the load factor
    // within the specified range.  A minimum load factor of 0 means that
    // the table will never shrink when elements are deleted from it.
    float        getMaxLoadFactor() const { return myMaxLoadFactor; }
    void         setMaxLoadFactor(float max_load_factor);
    float        getMinLoadFactor() const { return myMinLoadFactor; }
    void         setMinLoadFactor(float min_load_factor);

    // Merge the specified table with ourselves.
    void         mergeTable(const UT_HashTable &table);

    // "getHashReference" returns a pointer to the actual UT_Hash that
    // is maintained in the hash table. This can be used to implement
    // a shared hash symbol table.
    const UT_Hash       *getHashReference(const UT_Hash &hash);

    void         outputStats(FILE *output) const;
    void         outputStats(ostream &os) const;
    void         dumpTable(FILE *output) const;

    int64        getMemUsage(bool only_this) const;

    // "traverse" invokes the given function with every member of the
    // hash table. The order of traversal is undefined. If the function
    // returns a non-zero value the traversal continues. If it returns
    // zero then traversal stops. The return value is zero if the traversal
    // was interupted and one otherwise.
    //
    // Call traverseConst() if you will not be removing things from the table
    // while traversing, and traverse() if you might be.  If you call traverse()
    // and add something to the table, you may or may not encounter it later
    // in the traversal.
    int          traverseConst(
                          int (*function)(UT_Thing &, const UT_Hash&, void *),
                          void *data) const;
    int          traverse(int (*function)(UT_Thing &, const UT_Hash&, void *),
                          void *data);

    class UT_API traverser
    {
        public:
            traverser()
                : myCurrList(0), myEndList(0)
                         { }
            traverser(const traverser &src)
                         { *this = src; }
            ~traverser()
                         { }

            UT_Thing    &thing()
                         { return myCurrEntry.thing(); }
            UT_Hash     *hash()
                         { return myCurrEntry.hash(); }

            int          operator==(const traverser &cmp)
                         {
                             return ((!myCurrList && !cmp.myCurrList) ||
                                     ((myCurrList == cmp.myCurrList) &&
                                      (myCurrEntry == cmp.myCurrEntry)));
                         }
            int          operator!=(const traverser &cmp)
                         { return !(*this == cmp); }
            
            traverser   &operator++()
                         {
                             if( ++myCurrEntry == myCurrList->end() )
                             {
                                 ++myCurrList;
                                 advanceToNextList();
                             }
                             return *this;
                         }

            const traverser     &operator=(const traverser &src)
                         {
                             myCurrList = src.myCurrList;
                             myEndList = src.myEndList;
                             myCurrEntry = src.myCurrEntry;
                             return *this;
                         }

        private:
            traverser(const UT_ThingList *list, const UT_ThingList *endlist)
                : myCurrList(list), myEndList(endlist)
                         { advanceToNextList(); }

            void         advanceToNextList()
                         {
                             while( myCurrList != myEndList &&
                                    myCurrList->begin() == myCurrList->end() )
                                 ++myCurrList;
                             if( myCurrList == myEndList )
                                 myCurrList = 0;
                             else
                                 myCurrEntry = myCurrList->begin();
                         }

            const UT_ThingList          *myCurrList;
            const UT_ThingList          *myEndList;
            UT_ThingList::traverser      myCurrEntry;

            friend class UT_HashTable;
    };

    traverser    begin() const
    {
        if( myTable )
            return traverser(myTable, myTable + mySize);
        return traverser();     // same as end()
    }
    traverser    end() const
    { return traverser(); }

private:
    enum UT_AdjustType { UT_ADJUST_INCREASE, UT_ADJUST_DECREASE };
    void         adjustTableSize(UT_AdjustType adjust_type);

    // Data:
    UT_ThingList *myTable;
    int          mySize;
    unsigned int myNbrEntries;
    fpreal       myMaxLoadFactor;
    fpreal       myMinLoadFactor;
    bool         myUseOrdered;
    bool         myIsTraversing;
};

#endif

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