1 | /************************************************************************* |
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2 | * * |
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3 | * Open Dynamics Engine, Copyright (C) 2001,2002 Russell L. Smith. * |
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4 | * All rights reserved. Email: russ@q12.org Web: www.q12.org * |
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5 | * * |
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6 | * This library is free software; you can redistribute it and/or * |
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7 | * modify it under the terms of EITHER: * |
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8 | * (1) The GNU Lesser General Public License as published by the Free * |
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9 | * Software Foundation; either version 2.1 of the License, or (at * |
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10 | * your option) any later version. The text of the GNU Lesser * |
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11 | * General Public License is included with this library in the * |
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12 | * file LICENSE.TXT. * |
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13 | * (2) The BSD-style license that is included with this library in * |
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14 | * the file LICENSE-BSD.TXT. * |
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15 | * * |
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16 | * This library 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 files * |
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19 | * LICENSE.TXT and LICENSE-BSD.TXT for more details. * |
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20 | * * |
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21 | *************************************************************************/ |
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22 | |
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23 | #include <ode/common.h> |
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24 | #include <ode/error.h> |
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25 | #include <ode/memory.h> |
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26 | #include "obstack.h" |
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27 | |
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28 | //**************************************************************************** |
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29 | // macros and constants |
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30 | |
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31 | #define ROUND_UP_OFFSET_TO_EFFICIENT_SIZE(arena,ofs) \ |
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32 | ofs = (size_t) (dEFFICIENT_SIZE( ((intP)(arena)) + ofs ) - ((intP)(arena)) ); |
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33 | |
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34 | #define MAX_ALLOC_SIZE \ |
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35 | ((size_t)(dOBSTACK_ARENA_SIZE - sizeof (Arena) - EFFICIENT_ALIGNMENT + 1)) |
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36 | |
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37 | //**************************************************************************** |
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38 | // dObStack |
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39 | |
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40 | dObStack::dObStack() |
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41 | { |
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42 | first = 0; |
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43 | last = 0; |
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44 | current_arena = 0; |
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45 | current_ofs = 0; |
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46 | } |
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47 | |
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48 | |
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49 | dObStack::~dObStack() |
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50 | { |
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51 | // free all arenas |
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52 | Arena *a,*nexta; |
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53 | a = first; |
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54 | while (a) { |
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55 | nexta = a->next; |
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56 | dFree (a,dOBSTACK_ARENA_SIZE); |
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57 | a = nexta; |
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58 | } |
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59 | } |
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60 | |
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61 | |
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62 | void *dObStack::alloc (int num_bytes) |
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63 | { |
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64 | if ((size_t)num_bytes > MAX_ALLOC_SIZE) dDebug (0,"num_bytes too large"); |
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65 | |
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66 | // allocate or move to a new arena if necessary |
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67 | if (!first) { |
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68 | // allocate the first arena if necessary |
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69 | first = last = (Arena *) dAlloc (dOBSTACK_ARENA_SIZE); |
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70 | first->next = 0; |
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71 | first->used = sizeof (Arena); |
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72 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (first,first->used); |
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73 | } |
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74 | else { |
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75 | // we already have one or more arenas, see if a new arena must be used |
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76 | if ((last->used + num_bytes) > dOBSTACK_ARENA_SIZE) { |
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77 | if (!last->next) { |
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78 | last->next = (Arena *) dAlloc (dOBSTACK_ARENA_SIZE); |
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79 | last->next->next = 0; |
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80 | } |
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81 | last = last->next; |
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82 | last->used = sizeof (Arena); |
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83 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (last,last->used); |
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84 | } |
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85 | } |
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86 | |
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87 | // allocate an area in the arena |
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88 | char *c = ((char*) last) + last->used; |
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89 | last->used += num_bytes; |
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90 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (last,last->used); |
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91 | return c; |
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92 | } |
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93 | |
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94 | |
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95 | void dObStack::freeAll() |
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96 | { |
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97 | last = first; |
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98 | if (first) { |
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99 | first->used = sizeof(Arena); |
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100 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (first,first->used); |
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101 | } |
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102 | } |
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103 | |
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104 | |
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105 | void *dObStack::rewind() |
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106 | { |
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107 | current_arena = first; |
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108 | current_ofs = sizeof (Arena); |
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109 | if (current_arena) { |
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110 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs) |
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111 | return ((char*) current_arena) + current_ofs; |
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112 | } |
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113 | else return 0; |
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114 | } |
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115 | |
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116 | |
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117 | void *dObStack::next (int num_bytes) |
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118 | { |
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119 | // this functions like alloc, except that no new storage is ever allocated |
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120 | if (!current_arena) return 0; |
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121 | current_ofs += num_bytes; |
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122 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs); |
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123 | if (current_ofs >= current_arena->used) { |
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124 | current_arena = current_arena->next; |
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125 | if (!current_arena) return 0; |
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126 | current_ofs = sizeof (Arena); |
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127 | ROUND_UP_OFFSET_TO_EFFICIENT_SIZE (current_arena,current_ofs); |
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128 | } |
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129 | return ((char*) current_arena) + current_ofs; |
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130 | } |
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