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121 lines
4.5 KiB
C++
121 lines
4.5 KiB
C++
// Created on: 2002-04-12
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// Created by: Alexander GRIGORIEV
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// Copyright (c) 2002-2014 OPEN CASCADE SAS
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//
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// This file is part of Open CASCADE Technology software library.
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//
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// This library is free software; you can redistribute it and/or modify it under
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// the terms of the GNU Lesser General Public License version 2.1 as published
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// by the Free Software Foundation, with special exception defined in the file
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// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
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// distribution for complete text of the license and disclaimer of any warranty.
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//
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// Alternatively, this file may be used under the terms of Open CASCADE
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// commercial license or contractual agreement.
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#ifndef NCollection_IncAllocator_HeaderFile
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#define NCollection_IncAllocator_HeaderFile
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#include <NCollection_BaseAllocator.hxx>
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/**
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* Class NCollection_IncAllocator - incremental memory allocator. This class
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* allocates memory on request returning the pointer to an allocated
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* block. This memory is never returned to the system until the allocator is
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* destroyed.
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*
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* By comparison with the standard new() and malloc() calls, this method is
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* faster and consumes very small additional memory to maintain the heap.
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*
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* All pointers returned by Allocate() are aligned to the size of the data
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* type "aligned_t". To modify the size of memory blocks requested from the
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* OS, use the parameter of the constructor (measured in bytes); if this
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* parameter is smaller than 25 bytes on 32bit or 49 bytes on 64bit, the
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* block size will be the default 24 kbytes
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*/
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class NCollection_IncAllocator : public NCollection_BaseAllocator
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{
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public:
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// The type defining the alignement of allocated objects
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typedef void * aligned_t;
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// ---------- PUBLIC METHODS ----------
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//! Constructor
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Standard_EXPORT NCollection_IncAllocator (const size_t theBlockSize = DefaultBlockSize);
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//! Allocate memory with given size. Returns NULL on failure
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Standard_EXPORT virtual void* Allocate (const size_t size);
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//! Free a previously allocated memory. Does nothing
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Standard_EXPORT virtual void Free (void *anAddress);
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//! Diagnostic method, returns the total allocated size
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Standard_EXPORT size_t GetMemSize () const;
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//! Destructor (calls Clean() internally)
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Standard_EXPORT ~NCollection_IncAllocator ();
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//! Reallocation: it is always allowed but is only efficient with the
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//! last allocated item
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Standard_EXPORT void * Reallocate (void * anAddress,
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const size_t oldSize,
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const size_t newSize);
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//! Re-initialize the allocator so that the next Allocate call should
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//! start allocating in the very begining as though the allocator is just
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//! constructed. Warning: make sure that all previously allocated data are
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//! no more used in your code!
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//! @param doReleaseMem
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//! True - release all previously allocated memory, False - preserve it
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//! for future allocations.
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Standard_EXPORT void Reset (const Standard_Boolean
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doReleaseMem=Standard_True);
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static const size_t DefaultBlockSize = 24600;
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protected:
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struct IBlock;
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//! Flush all previously allocated data. All pointers returned by
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//! Allocate() become invalid -- be very careful with this
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Standard_EXPORT void Clean ();
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//! Allocate a new block and return a pointer to it
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//! ** only for internal usage **
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void * allocateNewBlock (const size_t cSize);
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private:
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// Prohibited methods
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NCollection_IncAllocator (const NCollection_IncAllocator&);
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NCollection_IncAllocator& operator = (const NCollection_IncAllocator&);
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protected:
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// ----- PROTECTED CLASS IBlock -------
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struct IBlock {
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aligned_t * allocateInBlock (const size_t cSize)
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{
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aligned_t * aResult = p_free_space;
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p_free_space += cSize;
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return aResult;
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}
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aligned_t * p_free_space;
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aligned_t * p_end_block;
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struct IBlock * p_next;
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};
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protected:
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// --------- PROTECTED FIELDS ---------
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IBlock * myFirstBlock;
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size_t mySize;
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size_t myMemSize;
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public:
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// Declaration of CASCADE RTTI
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DEFINE_STANDARD_RTTI (NCollection_IncAllocator, NCollection_BaseAllocator)
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};
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// Definition of HANDLE object using Standard_DefineHandle.hxx
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DEFINE_STANDARD_HANDLE (NCollection_IncAllocator, NCollection_BaseAllocator)
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#endif
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