/*************************************************************************
 *
 *  $RCSfile: BtreeDict.cxx,v $
 *
 *  $Revision: 1.1 $
 *
 *  last change: $Author: abi $ $Date: 2001-05-08 11:54:54 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (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.openoffice.org/license.html.
 *
 *  Software provided under this License is provided on an "AS IS" basis,
 *  WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
 *  WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS,
 *  MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING.
 *  See the License for the specific provisions governing your rights and
 *  obligations concerning the Software.
 *
 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
 *
 *  Copyright: 2000 by Sun Microsystems, Inc.
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): _______________________________________
 *
 *
 ************************************************************************/
#ifdef ABIDEBUG
#include <abidebug.hxx>
#endif
#ifndef __SGI_STL_VECTOR
#include <stl/vector>
#endif
#ifndef _XMLSEARCH_DB_BTREEDICT_HXX_
#include <db/BtreeDict.hxx>
#endif
#ifndef _XMLSEARCH_DB_BLOCK_HXX_
#include <db/Block.hxx>
#endif
#ifndef _XMLSEARCH_DB_BLOCKFACTORY_HXX_
#include <db/BlockFactory.hxx>
#endif
#ifndef _XMLSEARCH_DB_BLOCKMANAGER_HXX_
#include <db/BlockManager.hxx>
#endif
#ifndef _XMLSEARCH_DB_DBENV_HXX_
#include <db/DBEnv.hxx>
#endif
#ifndef _XMLEARCH_UTIL_RANDOMACCESSSTREAM_HXX_
#include <util/RandomAccessStream.hxx>
#endif
#ifndef _XMLSEARCH_DB_DBENVIMPL_HXX_
#include <util/DBEnvImpl.hxx>
#endif


extern xmlsearch::util::RandomAccessStream* theFile();


const sal_Int32 xmlsearch::db::BtreeDict::ENTHEADERLEN = 6;
const sal_Int32 xmlsearch::db::BtreeDict::BLOCKSIZE = 2048;
const sal_Int32 xmlsearch::db::BtreeDict::HEADERLEN = 8;
const sal_Int32 xmlsearch::db::BtreeDict::DATALEN
= xmlsearch::db::BtreeDict::BLOCKSIZE - xmlsearch::db::BtreeDict::HEADERLEN;

const sal_Int32 xmlsearch::db::BtreeDict::nBlocksLimit = 64;
const sal_Int32 xmlsearch::db::BtreeDict::MaxKeyLength = 255;
const sal_Int32 xmlsearch::db::BtreeDict::lastPtrIndex = 508;   //!!! Careful with that number, Eugene


namespace xmlsearch {

    namespace db {

        class DictBlock
            : public Block
        {
            friend class BtreeDict;


        public:

            DictBlock( const DBEnv* dbenv )
                : Block( dbenv )
            {
            }

            sal_Int32 free() const
            {
                return getFree() + firstEntry();
            }

            sal_Int32 numberOfEntries() const
            {
                return getInteger( 0 );
            }

            sal_Int32 nthPointer( sal_Int32 n ) const
            {
                return getInteger( 4*(n+1) );
            }

            sal_Int32 getChildIdx( sal_Int32 index ) const
            {
                return nthPointer( BtreeDict::lastPtrIndex - index );
            }

            sal_Int32 entryKeyLength( sal_Int32 i ) const
            {

                return getData()[i] & 0xFF;
            }

            sal_Int32 entryID( sal_Int32  i ) const
            {
                return getInteger(i + 2);
            }

            sal_Int32 entryCompression( sal_Int32 i ) const
            {
                return getData()[i+1] & 0xFF;
            }

            sal_Int32 entryLength( sal_Int32 entry ) const
            {
                return BtreeDict::ENTHEADERLEN + entryKeyLength( entry );
            }

            sal_Int32 entryKey( sal_Int32 entry ) const
            {
                return entry + BtreeDict::ENTHEADERLEN;
            }

            sal_Int32 firstEntry() const
            {
                return 4;
            }

            sal_Int32 nextEntry( sal_Int32 entry ) const
            {
                return entry + entryLength( entry );
            }

            void restoreKeyInBuffer( sal_Int32 entry, sal_Int8* buffer ) const
            {
                sal_Int32 howMany = entryKeyLength( entry );
                sal_Int32 where = entryCompression( entry );
                sal_Int32 from = entryKey( entry );
                while( howMany-- > 0 )
                    buffer[ where++ ] = getData()[ from++ ];
            }

            rtl::OUString restoreKey( sal_Int32 entry, sal_Int8* buffer ) const
            {
                sal_Int32 howMany = entryKeyLength( entry );
                sal_Int32 where = entryCompression( entry );
                sal_Int32 from = entryKey( entry );
                while( howMany-- > 0 )
                    buffer[ where++ ] = getData()[ from++ ];

                return rtl::OUString( (sal_Char*)(buffer),where,RTL_TEXTENCODING_UTF8 );
            }

            rtl::OUString findID( sal_Int32 id ) const throw( xmlsearch::excep::XmlSearchException  )
            {
                sal_Int8 buffer[ BtreeDict::MaxKeyLength ];
                sal_Int32 freeSpace = free();
                for( sal_Int32 ent = firstEntry(); ent < freeSpace; ent = nextEntry( ent ) )
                    if( entryID( ent ) == id )  // found
                        return restoreKey( ent,buffer );
                    else
                        restoreKeyInBuffer( ent,buffer );

                throw xmlsearch::excep::XmlSearchException(
                    rtl::OUString::createFromAscii( "DictBlock::findID -> ID not found in block" ) );
            }

            void withPrefix( const BtreeDict* owner,
                             const rtl::OUString& prefix,
                             sal_Int32 prefLen,
                             std::vector<sal_Int32>& result) const
                throw( xmlsearch::excep::XmlSearchException )
            {
                sal_Int8 buffer[ BtreeDict::MaxKeyLength ];
                const int freeSpace = free();
                int entryPtr = firstEntry();
                if( isLeaf() )
                    while (entryPtr < freeSpace)
                    {
                        if( restoreKey( entryPtr,buffer).compareTo( prefix,prefix.getLength() ) == 0 )
                            result.push_back( entryID( entryPtr ) );
                        entryPtr = nextEntry(entryPtr);
                    }
                else
                {
                    owner->lock( getNum() );
                    sal_Int32 entryIndex  = 0;
                    while( entryPtr < freeSpace )
                    {
                        rtl::OUString key = restoreKey( entryPtr,buffer );

                        if( key.getLength() > prefLen )
                            key = key.copy( 0,prefLen );
                        sal_Int32 cmp = key.compareTo(prefix);

                        if( cmp < 0 )
                        {
                            entryPtr = nextEntry( entryPtr );
                            ++entryIndex;
                        }
                        else if( cmp == 0 )
                        {
                            result.push_back( entryID( entryPtr ) );
                            owner->accessBlock( getChildIdx( entryIndex ) )->withPrefix( owner,prefix,prefLen,result );
                            entryPtr = nextEntry( entryPtr );
                            ++entryIndex;
                        }
                        else
                        {
                            owner->unlock( getNum() );
                            owner->accessBlock( getChildIdx( entryIndex ) )->withPrefix( owner,prefix,prefLen,result );
                            return;
                        }
                    }

                    owner->unlock( getNum() );
                    owner->accessBlock( getChildIdx( numberOfEntries() ) )->withPrefix( owner,prefix,prefLen,result );
                }
            }


            void setBlockNumbers( sal_Int32* blocks )
            {
                for( sal_Int32 e = firstEntry(); e < getFree() ; e = nextEntry(e) )
                    blocks[ entryID(e) ] = getNum();
            }


#ifdef ABIDEBUG
            void listBlock() const
            {
                sal_Int8 buffer[ BtreeDict::MaxKeyLength ];
                sal_Int32 freeSpace = free();
                sal_Int32 entryPtr = firstEntry();

                if ( isLeaf() )
                    while( entryPtr < freeSpace )
                    {
//                          cout << ( restoreKey( entryPtr,buffer ) + rtl::OUString::createFromAscii(" ") )
//                               <<   entryID( entryPtr )
//                               <<   endl;
                        entryPtr = nextEntry( entryPtr );
                    }
                else
                    cout << "not leaf";
            }
#endif


        protected:

            void doMap( BtreeDict* owner,EntryProcessor* processor ) const
                throw( xmlsearch::excep::XmlSearchException )
            {
                sal_Int8 buffer[ BtreeDict::MaxKeyLength ];
                sal_Int32 freeSpace = free();
                sal_Int32 entryPtr = firstEntry();

                if( isLeaf() )
                    while( entryPtr < freeSpace )
                    {
                        processor->processEntry( restoreKey( entryPtr,buffer ),
                                                 entryID( entryPtr ) );
                        entryPtr = nextEntry( entryPtr );
                    }
                else
                {
                    owner->lock( getNum() );
                    sal_Int8 entryIdx  = 0;
                    while( entryPtr < freeSpace )
                    {
                        owner->accessBlock( getChildIdx( entryIdx ) )->doMap( owner,processor );
                        processor->processEntry( restoreKey( entryPtr,buffer ),
                                                 entryID( entryPtr ) );
                        entryPtr = nextEntry( entryPtr );
                        ++entryIdx;
                    }
                    owner->accessBlock( getChildIdx( entryIdx ) )->doMap( owner,processor );
                    owner->unlock( getNum() );
                }
            }


        };  // end class DictBlock






    }   // end namespace db

}       // end namespace xmlsearch




using namespace xmlsearch;
using namespace xmlsearch::db;
using namespace xmlsearch::util;


class BlockProcessorImpl
  : public BlockProcessor
{
public:

  BlockProcessorImpl( BtreeDict* bla )
    : bla_( bla )
  {
  }


  ~BlockProcessorImpl()
  {
  }


  void process( Block* block ) const
  {
    dynamic_cast<DictBlock*>(block)->setBlockNumbers( bla_->get_blocks() );
  }


private:

  BtreeDict* bla_;
};





BtreeDict::BtreeDict( DBEnv* dbenv )
  : // parameter_( parameter ),
  blockManager_( dbenv ? dbenv : new DBEnvImpl() ),
  root_( 2 ),
  blocks_( new sal_Int32[5664] )
{
  BlockProcessorImpl blProc( this );
  blockManager_.mapBlocks( blProc );
}


BtreeDict::~BtreeDict()
{
  delete[] blocks_;
}


const DictBlock* BtreeDict::accessBlock( sal_Int32 id ) const
{
  return dynamic_cast< const DictBlock* >( blockManager_.accessBlock( id ) );
}


void BtreeDict::lock( sal_Int32 blNum ) const throw( excep::IllegalIndexException )
{
  blockManager_.lock( blNum );
}


void BtreeDict::unlock( sal_Int32 blNum ) const throw( excep::IllegalIndexException )
{
  blockManager_.unlock( blNum );
}

bool BtreeDict::isLocked( sal_Int32 blNum ) const throw( excep::IllegalIndexException )
{
  return blockManager_.isLocked( blNum );
}


sal_Int32 BtreeDict::fetch( const rtl::OUString& key ) const throw( excep::XmlSearchException )
{
  rtl::OString searchString( key.getStr(),key.getLength(),RTL_TEXTENCODING_UTF8 );

  return find( accessBlock( root_ ),
           reinterpret_cast< const sal_Int8* >( searchString.getStr() ),
           searchString.getLength() );
}


rtl::OUString BtreeDict::fetch( sal_Int32 conceptID ) const throw( excep::XmlSearchException )
{
  return findID( blocks_[conceptID], conceptID );
}


std::vector< sal_Int32 > BtreeDict::withPrefix( const rtl::OUString& prefix ) const
  throw( excep::XmlSearchException )
{
  std::vector< sal_Int32 > result;
  accessBlock( root_ )->withPrefix( this,prefix,prefix.getLength(),result );
  return result;
}



sal_Int32 BtreeDict::find( const DictBlock* bl,
               const sal_Int8* key,
               sal_Int32 inputKeyLen ) const throw( excep::XmlSearchException )
{
  sal_Int32 entryPtr    = bl->firstEntry();
  sal_Int32 freeSpace   = bl->free();
  sal_Int32 nCharsEqual = 0;
  sal_Int32 compression = 0;

  for( sal_Int32 entryIdx = 0; ; )
    {
      if( entryPtr == freeSpace )
    return find( bl,
             key,
             inputKeyLen,
             bl->numberOfEntries() );

      else if( compression == nCharsEqual )
    {
      sal_Int32 keyLen = bl->entryKeyLength( entryPtr );
      sal_Int32 keyPtr = bl->entryKey( entryPtr ), i;
      for( i = 0; i < keyLen && key[ nCharsEqual ] == bl->getData()[keyPtr + i]; i++ )
        ++nCharsEqual;
      if( i == keyLen )
        {
          if( nCharsEqual == inputKeyLen )
        return bl->entryID( entryPtr );
        }
      else if( ( key[ nCharsEqual ] & 0xFF ) < ( bl->getData()[ keyPtr + i ] & 0xFF) )
        return find( bl,key,inputKeyLen,entryIdx );
    }

      else if( compression < nCharsEqual ) // compression dropped
    return find( bl,key,inputKeyLen,entryPtr == freeSpace ? bl->numberOfEntries() : entryIdx );


      do
    {
      entryPtr = bl->nextEntry( entryPtr );
      ++entryIdx;
    } while( bl->entryCompression( entryPtr ) > nCharsEqual );

      compression = bl->entryCompression( entryPtr );
    }
}




sal_Int32 BtreeDict::find( const DictBlock* bl,
               const sal_Int8* key,
               sal_Int32 inputKeyLen,
               sal_Int32 index ) const throw( xmlsearch::excep::XmlSearchException )
{
  return bl->isLeaf() ? 0 : find( child( bl,index ),key,inputKeyLen );
}



const DictBlock* BtreeDict::child( const DictBlock* bl,sal_Int32 index) const throw( excep::XmlSearchException )
{
  return accessBlock( bl->getChildIdx(index) );
}


rtl::OUString BtreeDict::findID( sal_Int32 blNum,sal_Int32 id ) const throw( xmlsearch::excep::XmlSearchException )
{
  return accessBlock( blNum )->findID( id );
}











#ifndef _XMLSEARCH_UTIL_RANDOMACCESSSTREAM_HXX_
#include <util/RandomAccessStream.hxx>
#endif

void BtreeDict::test()
{
//    DictBlock* block = new DictBlock( DATALEN );
//    for( int i = 0; i < theFile()->length()/BLOCKSIZE; ++i )
//      {
//        theFile()->seek( i * BLOCKSIZE );
//        block->read( theFile() );
//        block->listBlock();
//      }

//    const DictBlock* bla = accessBlock(4);

//    if( ! bla )
//        ; //     cout << rtl::OUString::createFromAscii( "zero" ) << endl;
//    else
//        bla->listBlock();
}



// Definitions for DBEnvImpl



DBEnvImpl::DBEnvImpl()
{
    file_ = theFile();
}


DBEnvImpl::~DBEnvImpl()
{
}


sal_Int32 DBEnvImpl::getEntryHeaderLen() const
{
    return BtreeDict::ENTHEADERLEN;
}


sal_Int32 DBEnvImpl::getBlockCount() const
{
    return file_->length() / BtreeDict::BLOCKSIZE;
}

sal_Int32 DBEnvImpl::getMaximumBlockCount() const
{
    return BtreeDict::nBlocksLimit;
}

sal_Int32 util::DBEnvImpl::getDataLen() const
{
    return BtreeDict::DATALEN;
}


sal_Int32 DBEnvImpl::getBlockLen() const
{
    return BtreeDict::BLOCKSIZE;
}


void DBEnvImpl::read( sal_Int32 blNum,xmlsearch::db::Block*& block ) const
{
    if( ! block )
        block = new xmlsearch::db::DictBlock( this );

    file_->seek( blNum * getBlockLen() );

    block->read( file_ );

//      if( block->getNum() != blNum )
//         cout << rtl::OUString::createFromAscii( " aua aua " ) << endl;
}


void DBEnvImpl::write( sal_Int32 blNum,xmlsearch::db::Block* block )
{
    if( ! block )
        return;
}




void bla()
{
    BtreeDict source( new DBEnvImpl() );

    std::vector< sal_Int32 > bla = source.withPrefix( rtl::OUString::createFromAscii( "text" ) );
    for( sal_uInt32 i = 0; i < bla.size(); ++i )
        ; // cout << bla[i] << endl;

    //  source.test();
}




#ifdef ABIDEBUG

#include <qe/QueryProcessor.hxx>


void blu()
{
  rtl::OUString indexDir = rtl::OUString::createFromAscii( "//./home/ab106281/work/index" );
  qe::QueryProcessor proc( indexDir );

  vector< rtl::OUString > bla(1);

  bla[ 0 ] = rtl::OUString::createFromAscii( "text" );
  rtl::OUString scope = rtl::OUString::createFromAscii( "headingheading" );
  sal_Int32 nHits = 100;

  qe::QueryStatement statement( nHits,
                bla,
                scope );

  proc.processQuery( statement );
}


#endif