1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup ScoreHeap |
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5 | * |
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6 | * @brief Heap Handler implementation. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * COPYRIGHT (c) 1989-1999. |
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11 | * On-Line Applications Research Corporation (OAR). |
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12 | * |
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13 | * Copyright (c) 2010 embedded brains GmbH. |
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14 | * |
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15 | * The license and distribution terms for this file may be |
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16 | * found in the file LICENSE in this distribution or at |
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17 | * http://www.rtems.org/license/LICENSE. |
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18 | */ |
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19 | |
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20 | #if HAVE_CONFIG_H |
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21 | #include "config.h" |
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22 | #endif |
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23 | |
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24 | #include <rtems/system.h> |
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25 | #include <rtems/score/heapimpl.h> |
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26 | |
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27 | static void _Heap_Free_block( Heap_Control *heap, Heap_Block *block ) |
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28 | { |
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29 | Heap_Statistics *const stats = &heap->stats; |
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30 | Heap_Block *first_free; |
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31 | |
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32 | /* Statistics */ |
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33 | ++stats->used_blocks; |
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34 | --stats->frees; |
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35 | |
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36 | /* |
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37 | * The _Heap_Free() will place the block to the head of free list. We want |
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38 | * the new block at the end of the free list. So that initial and earlier |
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39 | * areas are consumed first. |
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40 | */ |
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41 | _Heap_Free( heap, (void *) _Heap_Alloc_area_of_block( block ) ); |
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42 | _Heap_Protection_free_all_delayed_blocks( heap ); |
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43 | first_free = _Heap_Free_list_first( heap ); |
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44 | _Heap_Free_list_remove( first_free ); |
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45 | _Heap_Free_list_insert_before( _Heap_Free_list_tail( heap ), first_free ); |
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46 | } |
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47 | |
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48 | static void _Heap_Merge_below( |
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49 | Heap_Control *heap, |
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50 | uintptr_t extend_area_begin, |
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51 | Heap_Block *first_block |
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52 | ) |
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53 | { |
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54 | uintptr_t const page_size = heap->page_size; |
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55 | uintptr_t const new_first_block_alloc_begin = |
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56 | _Heap_Align_up( extend_area_begin + HEAP_BLOCK_HEADER_SIZE, page_size ); |
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57 | uintptr_t const new_first_block_begin = |
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58 | new_first_block_alloc_begin - HEAP_BLOCK_HEADER_SIZE; |
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59 | uintptr_t const first_block_begin = (uintptr_t) first_block; |
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60 | uintptr_t const new_first_block_size = |
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61 | first_block_begin - new_first_block_begin; |
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62 | Heap_Block *const new_first_block = (Heap_Block *) new_first_block_begin; |
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63 | |
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64 | new_first_block->prev_size = first_block->prev_size; |
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65 | new_first_block->size_and_flag = new_first_block_size | HEAP_PREV_BLOCK_USED; |
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66 | |
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67 | _Heap_Free_block( heap, new_first_block ); |
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68 | } |
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69 | |
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70 | static void _Heap_Merge_above( |
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71 | Heap_Control *heap, |
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72 | Heap_Block *last_block, |
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73 | uintptr_t extend_area_end |
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74 | ) |
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75 | { |
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76 | uintptr_t const page_size = heap->page_size; |
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77 | uintptr_t const last_block_begin = (uintptr_t) last_block; |
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78 | uintptr_t const last_block_new_size = _Heap_Align_down( |
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79 | extend_area_end - last_block_begin - HEAP_BLOCK_HEADER_SIZE, |
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80 | page_size |
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81 | ); |
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82 | Heap_Block *const new_last_block = |
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83 | _Heap_Block_at( last_block, last_block_new_size ); |
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84 | |
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85 | new_last_block->size_and_flag = |
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86 | (last_block->size_and_flag - last_block_new_size) |
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87 | | HEAP_PREV_BLOCK_USED; |
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88 | |
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89 | _Heap_Block_set_size( last_block, last_block_new_size ); |
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90 | |
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91 | _Heap_Free_block( heap, last_block ); |
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92 | } |
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93 | |
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94 | static void _Heap_Link_below( |
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95 | Heap_Block *link, |
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96 | Heap_Block *last_block |
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97 | ) |
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98 | { |
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99 | uintptr_t const last_block_begin = (uintptr_t) last_block; |
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100 | uintptr_t const link_begin = (uintptr_t) link; |
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101 | |
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102 | last_block->size_and_flag = |
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103 | (link_begin - last_block_begin) | HEAP_PREV_BLOCK_USED; |
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104 | } |
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105 | |
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106 | static void _Heap_Link_above( |
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107 | Heap_Block *link, |
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108 | Heap_Block *first_block, |
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109 | Heap_Block *last_block |
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110 | ) |
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111 | { |
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112 | uintptr_t const link_begin = (uintptr_t) link; |
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113 | uintptr_t const first_block_begin = (uintptr_t) first_block; |
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114 | |
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115 | _Heap_Block_set_size( link, first_block_begin - link_begin ); |
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116 | |
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117 | last_block->size_and_flag |= HEAP_PREV_BLOCK_USED; |
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118 | } |
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119 | |
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120 | uintptr_t _Heap_Extend( |
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121 | Heap_Control *heap, |
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122 | void *extend_area_begin_ptr, |
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123 | uintptr_t extend_area_size, |
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124 | uintptr_t unused RTEMS_UNUSED |
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125 | ) |
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126 | { |
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127 | Heap_Statistics *const stats = &heap->stats; |
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128 | Heap_Block *const first_block = heap->first_block; |
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129 | Heap_Block *start_block = first_block; |
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130 | Heap_Block *merge_below_block = NULL; |
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131 | Heap_Block *merge_above_block = NULL; |
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132 | Heap_Block *link_below_block = NULL; |
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133 | Heap_Block *link_above_block = NULL; |
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134 | Heap_Block *extend_first_block = NULL; |
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135 | Heap_Block *extend_last_block = NULL; |
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136 | uintptr_t const page_size = heap->page_size; |
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137 | uintptr_t const min_block_size = heap->min_block_size; |
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138 | uintptr_t const extend_area_begin = (uintptr_t) extend_area_begin_ptr; |
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139 | uintptr_t const extend_area_end = extend_area_begin + extend_area_size; |
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140 | uintptr_t const free_size = stats->free_size; |
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141 | uintptr_t extend_first_block_size = 0; |
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142 | uintptr_t extended_size = 0; |
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143 | bool extend_area_ok = false; |
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144 | |
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145 | if ( extend_area_end < extend_area_begin ) { |
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146 | return 0; |
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147 | } |
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148 | |
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149 | extend_area_ok = _Heap_Get_first_and_last_block( |
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150 | extend_area_begin, |
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151 | extend_area_size, |
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152 | page_size, |
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153 | min_block_size, |
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154 | &extend_first_block, |
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155 | &extend_last_block |
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156 | ); |
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157 | if (!extend_area_ok ) { |
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158 | /* For simplicity we reject extend areas that are too small */ |
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159 | return 0; |
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160 | } |
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161 | |
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162 | do { |
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163 | uintptr_t const sub_area_begin = (start_block != first_block) ? |
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164 | (uintptr_t) start_block : heap->area_begin; |
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165 | uintptr_t const sub_area_end = start_block->prev_size; |
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166 | Heap_Block *const end_block = |
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167 | _Heap_Block_of_alloc_area( sub_area_end, page_size ); |
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168 | |
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169 | if ( |
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170 | sub_area_end > extend_area_begin && extend_area_end > sub_area_begin |
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171 | ) { |
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172 | return 0; |
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173 | } |
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174 | |
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175 | if ( extend_area_end == sub_area_begin ) { |
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176 | merge_below_block = start_block; |
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177 | } else if ( extend_area_end < sub_area_end ) { |
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178 | link_below_block = start_block; |
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179 | } |
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180 | |
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181 | if ( sub_area_end == extend_area_begin ) { |
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182 | start_block->prev_size = extend_area_end; |
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183 | |
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184 | merge_above_block = end_block; |
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185 | } else if ( sub_area_end < extend_area_begin ) { |
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186 | link_above_block = end_block; |
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187 | } |
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188 | |
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189 | start_block = _Heap_Block_at( end_block, _Heap_Block_size( end_block ) ); |
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190 | } while ( start_block != first_block ); |
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191 | |
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192 | if ( extend_area_begin < heap->area_begin ) { |
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193 | heap->area_begin = extend_area_begin; |
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194 | } else if ( heap->area_end < extend_area_end ) { |
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195 | heap->area_end = extend_area_end; |
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196 | } |
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197 | |
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198 | extend_first_block_size = |
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199 | (uintptr_t) extend_last_block - (uintptr_t) extend_first_block; |
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200 | |
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201 | extend_first_block->prev_size = extend_area_end; |
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202 | extend_first_block->size_and_flag = |
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203 | extend_first_block_size | HEAP_PREV_BLOCK_USED; |
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204 | _Heap_Protection_block_initialize( heap, extend_first_block ); |
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205 | |
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206 | extend_last_block->prev_size = extend_first_block_size; |
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207 | extend_last_block->size_and_flag = 0; |
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208 | _Heap_Protection_block_initialize( heap, extend_last_block ); |
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209 | |
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210 | if ( (uintptr_t) extend_first_block < (uintptr_t) heap->first_block ) { |
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211 | heap->first_block = extend_first_block; |
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212 | } else if ( (uintptr_t) extend_last_block > (uintptr_t) heap->last_block ) { |
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213 | heap->last_block = extend_last_block; |
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214 | } |
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215 | |
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216 | if ( merge_below_block != NULL ) { |
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217 | _Heap_Merge_below( heap, extend_area_begin, merge_below_block ); |
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218 | } else if ( link_below_block != NULL ) { |
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219 | _Heap_Link_below( |
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220 | link_below_block, |
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221 | extend_last_block |
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222 | ); |
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223 | } |
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224 | |
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225 | if ( merge_above_block != NULL ) { |
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226 | _Heap_Merge_above( heap, merge_above_block, extend_area_end ); |
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227 | } else if ( link_above_block != NULL ) { |
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228 | _Heap_Link_above( |
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229 | link_above_block, |
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230 | extend_first_block, |
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231 | extend_last_block |
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232 | ); |
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233 | } |
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234 | |
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235 | if ( merge_below_block == NULL && merge_above_block == NULL ) { |
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236 | _Heap_Free_block( heap, extend_first_block ); |
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237 | } |
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238 | |
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239 | _Heap_Set_last_block_size( heap ); |
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240 | |
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241 | extended_size = stats->free_size - free_size; |
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242 | |
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243 | /* Statistics */ |
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244 | stats->size += extended_size; |
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245 | |
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246 | return extended_size; |
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247 | } |
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