sl@0: // Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: // Hexadecimal trees - declaration
sl@0: //
sl@0: 
sl@0: #ifndef HEXTREE_H
sl@0: #define HEXTREE_H
sl@0: 
sl@0: #include <e32std.h>
sl@0: 
sl@0: /**
sl@0: Base class that provides the implementation for RHexTree, which is just a thin
sl@0: template.
sl@0: 
sl@0: An instance of this class can have up to eight 16-way prefix trees, with heights
sl@0: from 1 to 8. All the values are stored in the leaves. To find a value from a
sl@0: 32-bit key, first the key is decomposed into 8 hexadecimal digits and then the
sl@0: prefix tree with height matching the number of digits in the key (ignoring zeros
sl@0: to the left) is traversed using the sequence of digits in the key as the
sl@0: indexing string. Offsets are internally used instead of pointers to allow
sl@0: instances to be placed in a heap shared between several processes.
sl@0: */
sl@0: class RHexTreeBase
sl@0:     {
sl@0: public:
sl@0:     IMPORT_C void ResetAndDestroy();
sl@0: protected:
sl@0:     IMPORT_C RHexTreeBase(RHeap* aHeap);
sl@0:     IMPORT_C TInt SetAt(TUint aKey, TAny* aValue);
sl@0:     IMPORT_C TAny* At(TUint aKey) const;
sl@0: private:
sl@0:     TInt SetAt(TUint aKey, TAny* aLeaf, TInt aHeight);
sl@0:     TInt SetAt(TUint aKey, TAny* aLeaf, TInt aHeight, TAny* aNode, TInt aLevel);
sl@0:     TAny* At(TUint aKey, TInt aHeight) const;
sl@0:     void ResetAndDestroy(TInt aHeight, TAny* aNode, TInt aLevel);
sl@0: private:
sl@0:     enum { EMaxNumHexDigits = 8 };
sl@0: private:
sl@0:     RHeap* iHeap;
sl@0:     TInt iRootOffsets[EMaxNumHexDigits];
sl@0:     };
sl@0: 
sl@0: /**
sl@0: An associative array implementation optimised for the case where the keys are
sl@0: 32-bit codes with spatial locality of reference. The values can be of any
sl@0: self-contained data type (that is, without destructor or clean-up functions).
sl@0: It allows multiple-readers, single-writer concurrent access from different
sl@0: processes in an SMP-safe manner without locking, excluding deletion of
sl@0: individual key-value pairs.
sl@0: */
sl@0: template<class T>
sl@0: class RHexTree : public RHexTreeBase
sl@0:     {
sl@0: public:
sl@0:     inline RHexTree(RHeap* aHeap);
sl@0:     inline TInt SetAt(TUint aKey, T* aValue);
sl@0:     inline const T* At(TUint aKey) const;
sl@0:     inline T* At(TUint aKey);
sl@0:     };
sl@0: 
sl@0: #include <hextree.inl>
sl@0: 
sl@0: #endif // HEXTREE_H