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1 | // Created on: 2002-04-12 |
2 | // Created by: Alexander GRIGORIEV |
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3 | // Copyright (c) 2002-2014 OPEN CASCADE SAS |
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4 | // |
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5 | // This file is part of Open CASCADE Technology software library. |
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6 | // |
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7 | // This library is free software; you can redistribute it and/or modify it under |
8 | // the terms of the GNU Lesser General Public License version 2.1 as published |
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9 | // by the Free Software Foundation, with special exception defined in the file |
10 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
11 | // distribution for complete text of the license and disclaimer of any warranty. |
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12 | // |
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13 | // Alternatively, this file may be used under the terms of Open CASCADE |
14 | // commercial license or contractual agreement. |
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15 | |
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16 | #ifndef NCollection_IncAllocator_HeaderFile |
17 | #define NCollection_IncAllocator_HeaderFile |
18 | |
19 | #include <NCollection_BaseAllocator.hxx> |
20 | |
21 | /** |
22 | * Class NCollection_IncAllocator - incremental memory allocator. This class |
23 | * allocates memory on request returning the pointer to an allocated |
24 | * block. This memory is never returned to the system until the allocator is |
25 | * destroyed. |
26 | * |
27 | * By comparison with the standard new() and malloc() calls, this method is |
28 | * faster and consumes very small additional memory to maintain the heap. |
29 | * |
30 | * All pointers returned by Allocate() are aligned to the size of the data |
31 | * type "aligned_t". To modify the size of memory blocks requested from the |
32 | * OS, use the parameter of the constructor (measured in bytes); if this |
33 | * parameter is smaller than 25 bytes on 32bit or 49 bytes on 64bit, the |
34 | * block size will be the default 24 kbytes |
35 | */ |
36 | class NCollection_IncAllocator : public NCollection_BaseAllocator |
37 | { |
38 | public: |
39 | // The type defining the alignement of allocated objects |
40 | typedef void * aligned_t; |
41 | |
42 | // ---------- PUBLIC METHODS ---------- |
43 | |
44 | //! Constructor |
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45 | Standard_EXPORT NCollection_IncAllocator (const size_t theBlockSize = DefaultBlockSize); |
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46 | |
47 | //! Allocate memory with given size. Returns NULL on failure |
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48 | Standard_EXPORT virtual void* Allocate (const size_t size) Standard_OVERRIDE; |
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49 | |
50 | //! Free a previously allocated memory. Does nothing |
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51 | Standard_EXPORT virtual void Free (void *anAddress) Standard_OVERRIDE; |
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52 | |
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53 | //! Diagnostic method, returns the total allocated size |
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54 | Standard_EXPORT size_t GetMemSize () const; |
55 | |
56 | //! Destructor (calls Clean() internally) |
57 | Standard_EXPORT ~NCollection_IncAllocator (); |
58 | |
59 | //! Reallocation: it is always allowed but is only efficient with the |
60 | //! last allocated item |
61 | Standard_EXPORT void * Reallocate (void * anAddress, |
62 | const size_t oldSize, |
63 | const size_t newSize); |
64 | |
65 | //! Re-initialize the allocator so that the next Allocate call should |
66 | //! start allocating in the very begining as though the allocator is just |
67 | //! constructed. Warning: make sure that all previously allocated data are |
68 | //! no more used in your code! |
69 | //! @param doReleaseMem |
70 | //! True - release all previously allocated memory, False - preserve it |
71 | //! for future allocations. |
72 | Standard_EXPORT void Reset (const Standard_Boolean |
73 | doReleaseMem=Standard_True); |
74 | |
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75 | static const size_t DefaultBlockSize = 24600; |
76 | |
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77 | protected: |
78 | struct IBlock; |
79 | |
80 | //! Flush all previously allocated data. All pointers returned by |
81 | //! Allocate() become invalid -- be very careful with this |
82 | Standard_EXPORT void Clean (); |
83 | |
84 | //! Allocate a new block and return a pointer to it |
85 | //! ** only for internal usage ** |
86 | void * allocateNewBlock (const size_t cSize); |
87 | |
88 | private: |
89 | // Prohibited methods |
90 | NCollection_IncAllocator (const NCollection_IncAllocator&); |
91 | NCollection_IncAllocator& operator = (const NCollection_IncAllocator&); |
92 | |
93 | protected: |
94 | // ----- PROTECTED CLASS IBlock ------- |
95 | struct IBlock { |
96 | aligned_t * allocateInBlock (const size_t cSize) |
97 | { |
98 | aligned_t * aResult = p_free_space; |
99 | p_free_space += cSize; |
100 | return aResult; |
101 | } |
102 | aligned_t * p_free_space; |
103 | aligned_t * p_end_block; |
104 | struct IBlock * p_next; |
105 | }; |
106 | protected: |
107 | // --------- PROTECTED FIELDS --------- |
108 | IBlock * myFirstBlock; |
109 | size_t mySize; |
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110 | size_t myMemSize; |
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111 | |
112 | public: |
113 | // Declaration of CASCADE RTTI |
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114 | DEFINE_STANDARD_RTTI (NCollection_IncAllocator, NCollection_BaseAllocator) |
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115 | }; |
116 | |
117 | // Definition of HANDLE object using Standard_DefineHandle.hxx |
118 | DEFINE_STANDARD_HANDLE (NCollection_IncAllocator, NCollection_BaseAllocator) |
119 | |
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120 | #endif |