/*

 * 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.

 */

/*

 * $Id: DOMNodeIDMap.cpp 678144 2008-07-19 12:08:55Z borisk $

 */

#include "DOMAttrImpl.hpp"

#include "DOMDocumentImpl.hpp"

#include "DOMNodeIDMap.hpp"

#include <xercesc/util/XMLString.hpp>

#include <xercesc/util/RuntimeException.hpp>

#include <stdio.h>

XERCES_CPP_NAMESPACE_BEGIN

static const XMLSize_t gPrimes[] = {997, 9973, 99991, 999983, 0 };  // To do - add a few more.

static const float gMaxFill = 0.8f;   // The maximum fraction of the total

                                    // table entries to consume before exanding.

DOMNodeIDMap::DOMNodeIDMap(XMLSize_t initialSize, DOMDocument *doc)

: fNumEntries(0)

, fDoc(doc)

{

    for (fSizeIndex = 0; gPrimes[fSizeIndex] < initialSize; fSizeIndex++)

    {

        if (gPrimes[fSizeIndex] == 0)

        {

            // We need a bigger size than the largest available one.

            //   Big trouble.

            fSizeIndex--;

            ThrowXMLwithMemMgr(RuntimeException, XMLExcepts::NodeIDMap_GrowErr, ((DOMDocumentImpl *)fDoc)->getMemoryManager());

        }

    }

    fSize = gPrimes[fSizeIndex];

    fMaxEntries = (XMLSize_t)(float(fSize) * gMaxFill);

    //fTable = new (fDoc) DOMAttr*[fSize];

    fTable = (DOMAttr**) ((DOMDocumentImpl *)fDoc)->allocate(sizeof(DOMAttr*) * fSize);

    XMLSize_t i;

    for (i=0; i<fSize; i++)

        fTable[i] = 0;

}

DOMNodeIDMap::~DOMNodeIDMap()

{

    // don't delete - the document owns the storage.

    fTable = 0;

}

void DOMNodeIDMap::add(DOMAttr *attr)

{

  //

  //  If the table is getting too full, grow it.  We arbitrarily limit

  //   the table to 80 full, which should limit the average number of

  //   rehashes to a reasonable value.

  //

  if (fNumEntries >= fMaxEntries)

    growTable();

        fNumEntries++;

  //

  // Hash the value string from the ID attribute being added to the table

  //      0 < Initial hash value < table size.

  //      An initial hash of zero would cause the rehash to fail.

  //

  const XMLCh *id=attr->getValue();

        XMLSize_t initalHash = XMLString::hash(id, fSize-1);

  initalHash++;

  XMLSize_t currentHash = initalHash;

  //

  // Loop looking for an empty slot for this ID.

  //   Don't even bother checking to see if the ID is already there -

  //   the table is only filled by the parser from valid documents, which

  //   can not have duplicates.  Behavior of invalid docs is not defined.

  //

    while (fTable[currentHash]!=0 && fTable[currentHash]!=(DOMAttr *)-1)

  {

    currentHash += initalHash;  // rehash

        if (currentHash >= fSize)

            currentHash = currentHash % fSize;

    }

    //

    // We've found our slot.  Stick the pointer to the attr into it.

    //

    fTable[currentHash] = attr;

}

void DOMNodeIDMap::remove(DOMAttr *attr)

{

    //

  // Hash the value string from the ID attribute being added to the table

  //      0 < Initial hash value < table size.

  //      An initial hash of zero would cause the rehash to fail.

  //

  const XMLCh *id=attr->getValue();

        XMLSize_t initalHash = XMLString::hash(id, fSize-1);

  initalHash++;

  XMLSize_t currentHash = initalHash;

  //

  // Loop looking for a slot pointing to an attr with this id.

    //

  DOMAttr *tableSlot;

    while ((tableSlot= fTable[currentHash])!=0)

  {

        if (tableSlot == attr)

        {

            //  Found the attribute.  Set the slot to -1 to indicate

            //   that it was once used, meaning that lookups, while never

            //   matching here, can not stop either, but must rehash again

            //   and continue searching.

            fTable[currentHash] = (DOMAttr *)-1;

            return;

        }

        currentHash += initalHash;  // rehash.

        if (currentHash >= fSize)

            currentHash = currentHash % fSize;

    }

    // There is no matching entry in the table

}

DOMAttr *DOMNodeIDMap::find(const XMLCh *id)

{

    //

    //  Get the hashcode for the supplied string.

    //

    XMLSize_t initalHash = XMLString::hash(id, fSize-1);

  initalHash++;

  XMLSize_t currentHash = initalHash;

  //

  // Loop looking for a slot pointing to an attr with this id.

    //

  DOMAttr *tableSlot;

    while ((tableSlot= fTable[currentHash])!=0)

  {

        if ((tableSlot != (DOMAttr *)-1) && XMLString::equals(tableSlot->getValue(), id))

            return tableSlot;

        currentHash += initalHash;  // rehash

        if (currentHash >= fSize)

            currentHash = currentHash % fSize;

    }

    // There is no matching entry in the table

    return 0;

}

//

//  Grow the table to the next larger size.

//      It has gotten too full for efficient operation.

//     (We never fill it all the way)

//

void DOMNodeIDMap::growTable()

{

    DOMAttr     **oldTable = fTable;

    XMLSize_t oldSize  = fSize;

    //

    //  Figure the new table size.

    //

#if defined(XERCES_DEBUG)

    fprintf(stderr, "growing...\n");

#endif

    fSizeIndex++;

    fSize = gPrimes[fSizeIndex];

    if (fSize == 0)

    {

        // We need to grow bigger than the largest available size.

        //   Big trouble.

        fSizeIndex--;

        ThrowXMLwithMemMgr(RuntimeException, XMLExcepts::NodeIDMap_GrowErr, ((DOMDocumentImpl *)fDoc)->getMemoryManager());

    }

    //

    //  Allocate the new table.

    //

    //fTable = new (fDoc) DOMAttr *[fSize];

    fTable = (DOMAttr**) ((DOMDocumentImpl *)fDoc)->allocate(sizeof(DOMAttr*) * fSize);

    XMLSize_t i;

    for (i=0; i<fSize; i++)

        fTable[i] = 0;

    fMaxEntries = (XMLSize_t)(float(fSize) * gMaxFill);

    //

    // Move entries over from the old table to the new one.

    //

    for (i=0; i<oldSize; i++)

    {

        if ((oldTable[i] != 0)  &&  (oldTable[i] != (DOMAttr *)-1))

            add(oldTable[i]);

    }

    // delete [] oldTable;   (The document owns the storage.  The old table will just

    //                        need to leak until until the document is discarded.)

}

XERCES_CPP_NAMESPACE_END