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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT COMPILER COMPONENTS --
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4 -- --
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5 -- S Y S T E M . P O O L _ L O C A L --
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6 -- --
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7 -- B o d y --
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8 -- --
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131
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9 -- Copyright (C) 1992-2018, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- GNAT was originally developed by the GNAT team at New York University. --
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28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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29 -- --
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30 ------------------------------------------------------------------------------
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31
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32 with System.Memory;
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33
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34 with Ada.Unchecked_Conversion;
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35
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36 package body System.Pool_Local is
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37
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38 package SSE renames System.Storage_Elements;
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39 use type SSE.Storage_Offset;
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40
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41 Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
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42 Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
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43
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44 type Acc_Address is access all Address;
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45 function To_Acc_Address is
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46 new Ada.Unchecked_Conversion (Address, Acc_Address);
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47
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48 -----------------------
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49 -- Local Subprograms --
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50 -----------------------
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51
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52 function Next (A : Address) return Acc_Address;
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53 pragma Inline (Next);
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54 -- Given an address of a block, return an access to the next block
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55
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56 function Prev (A : Address) return Acc_Address;
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57 pragma Inline (Prev);
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58 -- Given an address of a block, return an access to the previous block
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59
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60 --------------
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61 -- Allocate --
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62 --------------
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63
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64 procedure Allocate
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65 (Pool : in out Unbounded_Reclaim_Pool;
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66 Address : out System.Address;
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67 Storage_Size : SSE.Storage_Count;
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68 Alignment : SSE.Storage_Count)
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69 is
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70 pragma Warnings (Off, Alignment);
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71
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72 Allocated : constant System.Address :=
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73 Memory.Alloc
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74 (Memory.size_t (Storage_Size + Pointers_Size));
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75
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76 begin
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77 -- The call to Alloc returns an address whose alignment is compatible
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78 -- with the worst case alignment requirement for the machine; thus the
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79 -- Alignment argument can be safely ignored.
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80
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81 if Allocated = Null_Address then
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82 raise Storage_Error;
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83 else
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84 Address := Allocated + Pointers_Size;
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85 Next (Allocated).all := Pool.First;
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86 Prev (Allocated).all := Null_Address;
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87
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88 if Pool.First /= Null_Address then
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89 Prev (Pool.First).all := Allocated;
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90 end if;
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91
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92 Pool.First := Allocated;
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93 end if;
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94 end Allocate;
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95
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96 ----------------
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97 -- Deallocate --
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98 ----------------
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99
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100 procedure Deallocate
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101 (Pool : in out Unbounded_Reclaim_Pool;
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102 Address : System.Address;
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103 Storage_Size : SSE.Storage_Count;
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104 Alignment : SSE.Storage_Count)
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105 is
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106 pragma Warnings (Off, Storage_Size);
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107 pragma Warnings (Off, Alignment);
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108
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109 Allocated : constant System.Address := Address - Pointers_Size;
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110
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111 begin
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112 if Prev (Allocated).all = Null_Address then
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113 Pool.First := Next (Allocated).all;
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114
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115 -- Comment needed
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116
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117 if Pool.First /= Null_Address then
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118 Prev (Pool.First).all := Null_Address;
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119 end if;
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120 else
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121 Next (Prev (Allocated).all).all := Next (Allocated).all;
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122 end if;
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123
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124 if Next (Allocated).all /= Null_Address then
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125 Prev (Next (Allocated).all).all := Prev (Allocated).all;
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126 end if;
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127
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128 Memory.Free (Allocated);
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129 end Deallocate;
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130
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131 --------------
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132 -- Finalize --
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133 --------------
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134
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135 procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
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136 N : System.Address := Pool.First;
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137 Allocated : System.Address;
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138
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139 begin
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140 while N /= Null_Address loop
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141 Allocated := N;
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142 N := Next (N).all;
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143 Memory.Free (Allocated);
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144 end loop;
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145 end Finalize;
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146
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147 ----------
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148 -- Next --
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149 ----------
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150
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151 function Next (A : Address) return Acc_Address is
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152 begin
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153 return To_Acc_Address (A);
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154 end Next;
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155
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156 ----------
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157 -- Prev --
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158 ----------
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159
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160 function Prev (A : Address) return Acc_Address is
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161 begin
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162 return To_Acc_Address (A + Pointer_Size);
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163 end Prev;
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164
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165 end System.Pool_Local;
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