1 | /* -*- C++ -*- */ |
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2 | |
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3 | /* |
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4 | |
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5 | Heap Layers: An Extensible Memory Allocation Infrastructure |
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6 | |
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7 | Copyright (C) 2000-2003 by Emery Berger |
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8 | http://www.cs.umass.edu/~emery |
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9 | emery@cs.umass.edu |
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10 | |
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11 | This program is free software; you can redistribute it and/or modify |
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12 | it under the terms of the GNU General Public License as published by |
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13 | the Free Software Foundation; either version 2 of the License, or |
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14 | (at your option) any later version. |
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15 | |
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16 | This program is distributed in the hope that it will be useful, |
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17 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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19 | GNU General Public License for more details. |
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20 | |
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21 | You should have received a copy of the GNU General Public License |
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22 | along with this program; if not, write to the Free Software |
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23 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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24 | |
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25 | */ |
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26 | |
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27 | #ifndef _SIZEHEAP_H_ |
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28 | #define _SIZEHEAP_H_ |
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29 | |
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30 | /** |
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31 | * @file sizeheap.h |
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32 | * @brief Contains UseSizeHeap and SizeHeap. |
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33 | */ |
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34 | |
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35 | #include <assert.h> |
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36 | |
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37 | #include "addheap.h" |
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38 | |
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39 | #if 1 |
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40 | |
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41 | /** |
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42 | * @class UseSizeHeap |
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43 | * @brief Adds a getSize method to access the size of an allocated object. |
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44 | * @see SizeHeap |
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45 | */ |
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46 | |
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47 | namespace HL { |
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48 | |
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49 | template <class Super> |
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50 | class UseSizeHeap : public Super { |
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51 | public: |
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52 | |
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53 | inline UseSizeHeap (void) {} |
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54 | |
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55 | inline static size_t getSize (const void * ptr) { |
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56 | return ((freeObject *) ptr - 1)->sz; |
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57 | } |
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58 | |
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59 | protected: |
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60 | union freeObject { |
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61 | size_t sz; |
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62 | double _dummy; // for alignment. |
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63 | }; |
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64 | }; |
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65 | |
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66 | /** |
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67 | * @class SizeHeap |
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68 | * @brief Allocates extra room for the size of an object. |
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69 | */ |
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70 | |
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71 | template <class SuperHeap> |
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72 | class SizeHeap : public UseSizeHeap<SuperHeap> { |
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73 | typedef typename UseSizeHeap<SuperHeap>::freeObject freeObject; |
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74 | public: |
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75 | inline SizeHeap (void) {} |
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76 | inline void * malloc (const size_t sz) { |
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77 | // Add room for a size field. |
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78 | freeObject * ptr = (freeObject *) |
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79 | SuperHeap::malloc (sz + sizeof(freeObject)); |
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80 | // Store the requested size. |
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81 | ptr->sz = sz; |
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82 | return (void *) (ptr + 1); |
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83 | } |
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84 | inline void free (void * ptr) { |
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85 | SuperHeap::free ((freeObject *) ptr - 1); |
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86 | } |
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87 | }; |
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88 | |
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89 | }; |
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90 | |
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91 | #else |
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92 | |
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93 | template <class Super> |
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94 | class SizeHeap : public Super { |
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95 | public: |
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96 | |
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97 | inline void * malloc (size_t sz) { |
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98 | // Add room for a size field. |
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99 | assert (sizeof(size_t) <= sizeof(double)); |
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100 | void * ptr = Super::malloc (sz + sizeof(double)); |
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101 | // Store the requested size. |
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102 | *((size_t *) ptr) = sz; |
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103 | return (void *) ((double *) ptr + 1); |
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104 | } |
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105 | |
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106 | inline void free (void * ptr) { |
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107 | void * origPtr = (void *) ((double *) ptr - 1); |
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108 | Super::free (origPtr); |
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109 | } |
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110 | |
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111 | inline static size_t getSize (void * ptr) { |
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112 | return *((size_t *) ((double *) ptr - 1)); |
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113 | } |
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114 | }; |
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115 | |
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116 | |
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117 | |
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118 | template <class Super> |
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119 | class UseSizeHeap : public Super { |
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120 | public: |
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121 | |
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122 | inline static size_t getSize (void * ptr) { |
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123 | return *((size_t *) ((double *) ptr - 1)); |
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124 | } |
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125 | }; |
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126 | |
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127 | #endif |
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128 | |
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129 | #endif |
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