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