homescreenpluginsrv/hspsdom/src/hspsdomstringpooloptimizer.cpp
branchRCL_3
changeset 18 bd874ee5e5e2
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9:d0529222e3f0 18:bd874ee5e5e2
       
     1 /*
       
     2 * Copyright (c) 2005,2006 Nokia Corporation and/or its subsidiary(-ies).
       
     3 * All rights reserved.
       
     4 * This component and the accompanying materials are made available
       
     5 * under the terms of "Eclipse Public License v1.0"
       
     6 * which accompanies this distribution, and is available
       
     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     8 *
       
     9 * Initial Contributors:
       
    10 * Nokia Corporation - initial contribution.
       
    11 *
       
    12 * Contributors:
       
    13 *
       
    14 * Description:  Optimizer module for ChspsDomStringPool.
       
    15 *
       
    16 */
       
    17 
       
    18 
       
    19 
       
    20 // INCLUDE FILES
       
    21 #include "hspsdomstringpooloptimizer.h"
       
    22 
       
    23 const TInt KMaxEstimateThreshold = 2;
       
    24 
       
    25 // ============================ MEMBER FUNCTIONS ===============================
       
    26 
       
    27 // -----------------------------------------------------------------------------
       
    28 // ThspsDomStringPoolOptimizerEntry::ThspsDomStringPoolOptimizerEntry
       
    29 // -----------------------------------------------------------------------------
       
    30 //
       
    31 ThspsDomStringPoolOptimizerEntry::ThspsDomStringPoolOptimizerEntry( TInt aIndex,
       
    32         const TDesC8& aString) :         
       
    33         iIndex( aIndex ),
       
    34         iString( aString )
       
    35     {
       
    36     }
       
    37 
       
    38 // -----------------------------------------------------------------------------
       
    39 // ThspsDomStringPoolOptimizer::AddEntryL
       
    40 // -----------------------------------------------------------------------------
       
    41 //
       
    42 void ThspsDomStringPoolOptimizer::AddEntryL( ThspsDomStringPoolOptimizerEntry& aEntry )
       
    43     {
       
    44     TBool positionFound = EFalse;
       
    45     
       
    46     if( iEntries.Count() > 0 )
       
    47         {    
       
    48         const TInt estimate = FindInsertionIndexEstimate(
       
    49                 aEntry.iString,
       
    50                 0,
       
    51                 iEntries.Count() - 1 );        
       
    52         
       
    53         if( estimate != KErrNotFound )
       
    54             {
       
    55             for( TInt i = estimate; i < iEntries.Count(); i++ )
       
    56                 {
       
    57                 if( aEntry.iString.Compare( iEntries[i].iString ) < 0 )
       
    58                     {
       
    59                     positionFound = ETrue;
       
    60                     iEntries.InsertL( aEntry, i );
       
    61                     break;
       
    62                     }
       
    63                 }
       
    64             }
       
    65         }
       
    66     
       
    67     if( !positionFound )
       
    68         {
       
    69         iEntries.AppendL( aEntry );
       
    70         }
       
    71     }
       
    72     
       
    73 // -----------------------------------------------------------------------------
       
    74 // ThspsDomStringPoolOptimizer::ThspsDomStringPoolOptimizerGetIndex
       
    75 // -----------------------------------------------------------------------------
       
    76 //
       
    77 TInt ThspsDomStringPoolOptimizer::GetIndex( const TDesC8& aString )
       
    78     {
       
    79     if( iEntries.Count() == 0 )
       
    80         {
       
    81         return KErrNotFound;
       
    82         }    
       
    83     
       
    84     TInt index = FindEntry( aString, 0, iEntries.Count() - 1 );
       
    85     if( index >= 0 && index < iEntries.Count() )
       
    86         {
       
    87         return iEntries[index].iIndex;
       
    88         }
       
    89     else
       
    90         {
       
    91         // Error code.
       
    92         return index;
       
    93         }
       
    94     }
       
    95 
       
    96 // -----------------------------------------------------------------------------
       
    97 // ThspsDomStringPoolOptimizer::Close
       
    98 // -----------------------------------------------------------------------------
       
    99 //
       
   100 void ThspsDomStringPoolOptimizer::Close()
       
   101     {
       
   102     iEntries.Close();
       
   103     }
       
   104 
       
   105 // -----------------------------------------------------------------------------
       
   106 // ThspsDomStringPoolOptimizer::Count
       
   107 // -----------------------------------------------------------------------------
       
   108 //
       
   109 TInt ThspsDomStringPoolOptimizer::Count()
       
   110     {
       
   111     return iEntries.Count();
       
   112     }
       
   113 
       
   114 // -----------------------------------------------------------------------------
       
   115 // ThspsDomStringPoolOptimizer::Entry
       
   116 // -----------------------------------------------------------------------------
       
   117 //
       
   118 ThspsDomStringPoolOptimizerEntry& ThspsDomStringPoolOptimizer::Entry(
       
   119         const TInt aIndex )
       
   120     {    
       
   121     return iEntries[ aIndex ];
       
   122     }
       
   123 
       
   124 // -----------------------------------------------------------------------------
       
   125 // ThspsDomStringPoolOptimizer::Reset
       
   126 // -----------------------------------------------------------------------------
       
   127 //
       
   128 void ThspsDomStringPoolOptimizer::Reset()
       
   129     {
       
   130     iEntries.Reset();
       
   131     }
       
   132 
       
   133 // -----------------------------------------------------------------------------
       
   134 // ThspsDomStringPoolOptimizer::FindEntry
       
   135 // -----------------------------------------------------------------------------
       
   136 //
       
   137 TInt ThspsDomStringPoolOptimizer::FindEntry( const TDesC8& aString,
       
   138         const TInt aLeft,
       
   139         const TInt aRight )
       
   140     {    
       
   141     if( aLeft > aRight )
       
   142         {
       
   143         return KErrNotFound;
       
   144         }
       
   145     
       
   146     const TUint middle = ( aLeft + aRight ) >> 1; // >> 1 means "divided by two".    
       
   147     ThspsDomStringPoolOptimizerEntry& entryAtMiddle = iEntries[ middle ];    
       
   148     const TInt comparisonResult = aString.Compare( entryAtMiddle.iString );
       
   149     
       
   150     if( comparisonResult > 0 )
       
   151         {
       
   152         return FindEntry( aString, middle + 1, aRight);
       
   153         }
       
   154     else if( comparisonResult < 0 )
       
   155         {
       
   156         return FindEntry( aString, aLeft, middle - 1 );
       
   157         }
       
   158     else
       
   159         {
       
   160         return  middle;
       
   161         }    
       
   162     }
       
   163 
       
   164 // -----------------------------------------------------------------------------
       
   165 // ThspsDomStringPoolOptimizer::FindEntry
       
   166 // -----------------------------------------------------------------------------
       
   167 //
       
   168 TInt ThspsDomStringPoolOptimizer::FindInsertionIndexEstimate( const TDesC8& aString,
       
   169         const TInt aLeft,
       
   170         const TInt aRight )
       
   171     {
       
   172     if( ( aRight - aLeft ) <= KMaxEstimateThreshold )
       
   173         {
       
   174         return aLeft;
       
   175         }
       
   176     
       
   177     const TUint middle = ( aLeft + aRight ) >> 1;      
       
   178          
       
   179     ThspsDomStringPoolOptimizerEntry& entryAtMiddle = iEntries[ middle ];    
       
   180     const TInt comparisonResult = aString.Compare( entryAtMiddle.iString );
       
   181         
       
   182     if( comparisonResult > 0 )
       
   183         {
       
   184         return FindInsertionIndexEstimate( aString, middle, aRight);
       
   185         }
       
   186     else if( comparisonResult < 0 )
       
   187         {
       
   188         return FindInsertionIndexEstimate( aString, aLeft, middle );
       
   189         }
       
   190     else
       
   191         {
       
   192         // Should not go here. There should be only one of a kind in the list.
       
   193         return KErrNotFound;
       
   194         }
       
   195     }
       
   196 
       
   197 //  End of File