111
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1 /* Sparse Arrays for Objective C dispatch tables
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145
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2 Copyright (C) 1993-2020 Free Software Foundation, Inc.
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111
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3
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4 This file is part of GCC.
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5
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6 GCC is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 3, or (at your option)
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9 any later version.
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10
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11 GCC is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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15
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16 Under Section 7 of GPL version 3, you are granted additional
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17 permissions described in the GCC Runtime Library Exception, version
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18 3.1, as published by the Free Software Foundation.
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19
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20 You should have received a copy of the GNU General Public License and
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21 a copy of the GCC Runtime Library Exception along with this program;
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22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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23 <http://www.gnu.org/licenses/>. */
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24
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25 #include "objc-private/common.h"
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26 #include "objc-private/sarray.h"
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27 #include "objc/runtime.h" /* For objc_malloc */
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28 #include "objc/thr.h" /* For objc_mutex_lock */
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29 #include "objc-private/module-abi-8.h"
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30 #include "objc-private/runtime.h"
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31 #include <stdio.h>
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32 #include <string.h> /* For memset */
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33 #include <assert.h> /* For assert */
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34
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35 int nbuckets = 0; /* !T:MUTEX */
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36 int nindices = 0; /* !T:MUTEX */
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37 int narrays = 0; /* !T:MUTEX */
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38 int idxsize = 0; /* !T:MUTEX */
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39
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40 static void *first_free_data = NULL; /* !T:MUTEX */
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41
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42 #ifdef OBJC_SPARSE2
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43 const char *__objc_sparse2_id = "2 level sparse indices";
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44 #endif
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45
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46 #ifdef OBJC_SPARSE3
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47 const char *__objc_sparse3_id = "3 level sparse indices";
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48 #endif
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49
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50 /* This function removes any structures left over from free operations
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51 that were not safe in a multi-threaded environment. */
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52 void
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53 sarray_remove_garbage (void)
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54 {
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55 void **vp;
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56 void *np;
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57
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58 objc_mutex_lock (__objc_runtime_mutex);
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59
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60 vp = first_free_data;
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61 first_free_data = NULL;
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62
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63 while (vp)
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64 {
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65 np = *vp;
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66 objc_free (vp);
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67 vp = np;
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68 }
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69
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70 objc_mutex_unlock (__objc_runtime_mutex);
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71 }
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72
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73 /* Free a block of dynamically allocated memory. If we are in
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74 multi-threaded mode, it is ok to free it. If not, we add it to the
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75 garbage heap to be freed later. */
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76 static void
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77 sarray_free_garbage (void *vp)
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78 {
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79 objc_mutex_lock (__objc_runtime_mutex);
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80
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81 if (__objc_runtime_threads_alive == 1)
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82 {
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83 objc_free (vp);
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84 if (first_free_data)
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85 sarray_remove_garbage ();
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86 }
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87 else
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88 {
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89 *(void **)vp = first_free_data;
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90 first_free_data = vp;
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91 }
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92
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93 objc_mutex_unlock (__objc_runtime_mutex);
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94 }
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95
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96 /* sarray_at_put copies data in such a way as to be thread reader
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97 safe. */
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98 void
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99 sarray_at_put (struct sarray *array, sidx index, void *element)
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100 {
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101 #ifdef OBJC_SPARSE3
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102 struct sindex **the_index;
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103 struct sindex *new_index;
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104 #endif
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105 struct sbucket **the_bucket;
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106 struct sbucket *new_bucket;
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107 #ifdef OBJC_SPARSE3
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108 size_t ioffset;
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109 #endif
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110 size_t boffset;
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111 size_t eoffset;
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112 #ifdef PRECOMPUTE_SELECTORS
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113 union sofftype xx;
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114 xx.idx = index;
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115 #ifdef OBJC_SPARSE3
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116 ioffset = xx.off.ioffset;
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117 #endif
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118 boffset = xx.off.boffset;
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119 eoffset = xx.off.eoffset;
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120 #else /* not PRECOMPUTE_SELECTORS */
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121 #ifdef OBJC_SPARSE3
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122 ioffset = index/INDEX_CAPACITY;
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123 boffset = (index/BUCKET_SIZE)%INDEX_SIZE;
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124 eoffset = index%BUCKET_SIZE;
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125 #else
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126 boffset = index/BUCKET_SIZE;
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127 eoffset = index%BUCKET_SIZE;
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128 #endif
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129 #endif /* not PRECOMPUTE_SELECTORS */
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130
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131 assert (soffset_decode (index) < array->capacity); /* Range check */
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132
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133 #ifdef OBJC_SPARSE3
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134 the_index = &(array->indices[ioffset]);
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135 the_bucket = &((*the_index)->buckets[boffset]);
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136 #else
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137 the_bucket = &(array->buckets[boffset]);
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138 #endif
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139
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140 if ((*the_bucket)->elems[eoffset] == element)
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141 return; /* Great! we just avoided a lazy copy. */
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142
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143 #ifdef OBJC_SPARSE3
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144
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145 /* First, perform lazy copy/allocation of index if needed. */
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146
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147 if ((*the_index) == array->empty_index)
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148 {
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149 /* The index was previously empty, allocate a new. */
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150 new_index = (struct sindex *) objc_malloc (sizeof (struct sindex));
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151 memcpy (new_index, array->empty_index, sizeof (struct sindex));
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152 new_index->version.version = array->version.version;
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153 *the_index = new_index; /* Prepared for install. */
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154 the_bucket = &((*the_index)->buckets[boffset]);
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155
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156 nindices += 1;
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157 }
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158 else if ((*the_index)->version.version != array->version.version)
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159 {
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160 /* This index must be lazy copied. */
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161 struct sindex *old_index = *the_index;
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162 new_index = (struct sindex *) objc_malloc (sizeof (struct sindex));
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163 memcpy (new_index, old_index, sizeof (struct sindex));
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164 new_index->version.version = array->version.version;
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165 *the_index = new_index; /* Prepared for install. */
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166 the_bucket = &((*the_index)->buckets[boffset]);
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167
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168 nindices += 1;
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169 }
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170
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171 #endif /* OBJC_SPARSE3 */
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172
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173 /* Next, perform lazy allocation/copy of the bucket if needed. */
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174 if ((*the_bucket) == array->empty_bucket)
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175 {
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176 /* The bucket was previously empty (or something like that),
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177 allocate a new. This is the effect of `lazy' allocation. */
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178 new_bucket = (struct sbucket *) objc_malloc (sizeof (struct sbucket));
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179 memcpy ((void *) new_bucket, (const void *) array->empty_bucket,
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180 sizeof (struct sbucket));
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181 new_bucket->version.version = array->version.version;
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182 *the_bucket = new_bucket; /* Prepared for install. */
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183
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184 nbuckets += 1;
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185
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186 }
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187 else if ((*the_bucket)->version.version != array->version.version)
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188 {
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189 /* Perform lazy copy. */
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190 struct sbucket *old_bucket = *the_bucket;
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191 new_bucket = (struct sbucket *) objc_malloc (sizeof (struct sbucket));
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192 memcpy (new_bucket, old_bucket, sizeof (struct sbucket));
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193 new_bucket->version.version = array->version.version;
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194 *the_bucket = new_bucket; /* Prepared for install. */
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195
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196 nbuckets += 1;
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197 }
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198 (*the_bucket)->elems[eoffset] = element;
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199 }
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200
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201 void
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202 sarray_at_put_safe (struct sarray *array, sidx index, void *element)
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203 {
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204 if (soffset_decode (index) >= array->capacity)
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205 sarray_realloc (array, soffset_decode (index) + 1);
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206 sarray_at_put (array, index, element);
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207 }
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208
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209 struct sarray *
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210 sarray_new (int size, void *default_element)
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211 {
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212 struct sarray *arr;
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213 #ifdef OBJC_SPARSE3
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214 size_t num_indices = ((size - 1)/(INDEX_CAPACITY)) + 1;
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215 struct sindex **new_indices;
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216 #else /* OBJC_SPARSE2 */
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217 size_t num_indices = ((size - 1)/BUCKET_SIZE) + 1;
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218 struct sbucket **new_buckets;
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219 #endif
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220 size_t counter;
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221
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222 assert (size > 0);
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223
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224 /* Allocate core array. */
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225 arr = (struct sarray *) objc_malloc (sizeof (struct sarray));
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226 arr->version.version = 0;
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227
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228 /* Initialize members. */
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229 #ifdef OBJC_SPARSE3
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230 arr->capacity = num_indices*INDEX_CAPACITY;
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231 new_indices = (struct sindex **)
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232 objc_malloc (sizeof (struct sindex *) * num_indices);
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233
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234 arr->empty_index = (struct sindex *) objc_malloc (sizeof (struct sindex));
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235 arr->empty_index->version.version = 0;
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236
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237 narrays += 1;
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238 idxsize += num_indices;
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239 nindices += 1;
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240
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241 #else /* OBJC_SPARSE2 */
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242 arr->capacity = num_indices*BUCKET_SIZE;
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243 new_buckets = (struct sbucket **)
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244 objc_malloc (sizeof (struct sbucket *) * num_indices);
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245
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246 narrays += 1;
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247 idxsize += num_indices;
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248
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249 #endif
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250
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251 arr->empty_bucket = (struct sbucket *) objc_malloc (sizeof (struct sbucket));
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252 arr->empty_bucket->version.version = 0;
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253
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254 nbuckets += 1;
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255
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256 arr->ref_count = 1;
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257 arr->is_copy_of = (struct sarray *) 0;
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258
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259 for (counter = 0; counter < BUCKET_SIZE; counter++)
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260 arr->empty_bucket->elems[counter] = default_element;
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261
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262 #ifdef OBJC_SPARSE3
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263 for (counter = 0; counter < INDEX_SIZE; counter++)
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264 arr->empty_index->buckets[counter] = arr->empty_bucket;
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265
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266 for (counter = 0; counter < num_indices; counter++)
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267 new_indices[counter] = arr->empty_index;
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268
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269 #else /* OBJC_SPARSE2 */
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270
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271 for (counter = 0; counter < num_indices; counter++)
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272 new_buckets[counter] = arr->empty_bucket;
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273
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274 #endif
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275
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276 #ifdef OBJC_SPARSE3
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277 arr->indices = new_indices;
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278 #else /* OBJC_SPARSE2 */
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279 arr->buckets = new_buckets;
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280 #endif
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281
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282 return arr;
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283 }
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284
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285
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286 /* Reallocate the sparse array to hold `newsize' entries Note: We
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287 really allocate and then free. We have to do this to ensure that
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288 any concurrent readers notice the update. */
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289 void
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290 sarray_realloc (struct sarray *array, int newsize)
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291 {
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292 #ifdef OBJC_SPARSE3
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293 size_t old_max_index = (array->capacity - 1)/INDEX_CAPACITY;
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294 size_t new_max_index = ((newsize - 1)/INDEX_CAPACITY);
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295 size_t rounded_size = (new_max_index + 1) * INDEX_CAPACITY;
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296
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297 struct sindex **new_indices;
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298 struct sindex **old_indices;
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299
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300 #else /* OBJC_SPARSE2 */
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301 size_t old_max_index = (array->capacity - 1)/BUCKET_SIZE;
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302 size_t new_max_index = ((newsize - 1)/BUCKET_SIZE);
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303 size_t rounded_size = (new_max_index + 1) * BUCKET_SIZE;
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304
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305 struct sbucket **new_buckets;
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306 struct sbucket **old_buckets;
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307
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308 #endif
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309
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310 size_t counter;
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311
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312 assert (newsize > 0);
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313
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314 /* The size is the same, just ignore the request. */
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315 if (rounded_size <= array->capacity)
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316 return;
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317
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318 assert (array->ref_count == 1); /* stop if lazy copied... */
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319
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320 /* We are asked to extend the array -- allocate new bucket table,
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321 and insert empty_bucket in newly allocated places. */
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322 if (rounded_size > array->capacity)
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323 {
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324 #ifdef OBJC_SPARSE3
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325 new_max_index += 4;
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326 rounded_size = (new_max_index + 1) * INDEX_CAPACITY;
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327 #else /* OBJC_SPARSE2 */
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328 new_max_index += 4;
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329 rounded_size = (new_max_index + 1) * BUCKET_SIZE;
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330 #endif
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331
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332 /* Update capacity. */
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333 array->capacity = rounded_size;
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334
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335 #ifdef OBJC_SPARSE3
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336 /* Alloc to force re-read by any concurrent readers. */
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337 old_indices = array->indices;
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338 new_indices = (struct sindex **)
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339 objc_malloc ((new_max_index + 1) * sizeof (struct sindex *));
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340 #else /* OBJC_SPARSE2 */
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341 old_buckets = array->buckets;
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342 new_buckets = (struct sbucket **)
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343 objc_malloc ((new_max_index + 1) * sizeof (struct sbucket *));
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344 #endif
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345
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346 /* Copy buckets below old_max_index (they are still valid). */
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347 for (counter = 0; counter <= old_max_index; counter++ )
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348 {
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349 #ifdef OBJC_SPARSE3
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350 new_indices[counter] = old_indices[counter];
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351 #else /* OBJC_SPARSE2 */
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352 new_buckets[counter] = old_buckets[counter];
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353 #endif
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354 }
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355
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356 #ifdef OBJC_SPARSE3
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357 /* Reset entries above old_max_index to empty_bucket. */
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358 for (counter = old_max_index + 1; counter <= new_max_index; counter++)
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359 new_indices[counter] = array->empty_index;
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360 #else /* OBJC_SPARSE2 */
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361 /* Reset entries above old_max_index to empty_bucket. */
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362 for (counter = old_max_index + 1; counter <= new_max_index; counter++)
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363 new_buckets[counter] = array->empty_bucket;
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364 #endif
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365
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366 #ifdef OBJC_SPARSE3
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367 /* Install the new indices. */
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368 array->indices = new_indices;
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369 #else /* OBJC_SPARSE2 */
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370 array->buckets = new_buckets;
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371 #endif
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372
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373 #ifdef OBJC_SPARSE3
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374 /* Free the old indices. */
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375 sarray_free_garbage (old_indices);
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376 #else /* OBJC_SPARSE2 */
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377 sarray_free_garbage (old_buckets);
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378 #endif
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379
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380 idxsize += (new_max_index-old_max_index);
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381 return;
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382 }
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383 }
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384
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385
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386 /* Free a sparse array allocated with sarray_new */
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387 void
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388 sarray_free (struct sarray *array) {
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389 #ifdef OBJC_SPARSE3
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390 size_t old_max_index = (array->capacity - 1)/INDEX_CAPACITY;
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391 struct sindex **old_indices;
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392 #else
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393 size_t old_max_index = (array->capacity - 1)/BUCKET_SIZE;
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394 struct sbucket **old_buckets;
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395 #endif
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396 size_t counter = 0;
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397
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398 assert (array->ref_count != 0); /* Freed multiple times!!! */
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399
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400 if (--(array->ref_count) != 0) /* There exists copies of me */
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401 return;
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402
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403 #ifdef OBJC_SPARSE3
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404 old_indices = array->indices;
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405 #else
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406 old_buckets = array->buckets;
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407 #endif
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408
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409 /* Free all entries that do not point to empty_bucket. */
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410 for (counter = 0; counter <= old_max_index; counter++ )
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411 {
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412 #ifdef OBJC_SPARSE3
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413 struct sindex *idx = old_indices[counter];
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414 if ((idx != array->empty_index)
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415 && (idx->version.version == array->version.version))
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416 {
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417 int c2;
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418 for (c2 = 0; c2 < INDEX_SIZE; c2++)
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419 {
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420 struct sbucket *bkt = idx->buckets[c2];
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421 if ((bkt != array->empty_bucket)
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422 && (bkt->version.version == array->version.version))
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423 {
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424 sarray_free_garbage (bkt);
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425 nbuckets -= 1;
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426 }
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427 }
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428 sarray_free_garbage (idx);
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429 nindices -= 1;
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430 }
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431 #else /* OBJC_SPARSE2 */
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432 struct sbucket *bkt = old_buckets[counter];
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433 if ((bkt != array->empty_bucket)
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434 && (bkt->version.version == array->version.version))
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435 {
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436 sarray_free_garbage (bkt);
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437 nbuckets -= 1;
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438 }
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439 #endif
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440 }
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441
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442 #ifdef OBJC_SPARSE3
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443 /* Free empty_index. */
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444 if (array->empty_index->version.version == array->version.version)
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445 {
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446 sarray_free_garbage (array->empty_index);
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447 nindices -= 1;
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448 }
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449 #endif
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450
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451 /* Free empty_bucket. */
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452 if (array->empty_bucket->version.version == array->version.version)
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453 {
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454 sarray_free_garbage (array->empty_bucket);
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455 nbuckets -= 1;
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456 }
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457 idxsize -= (old_max_index + 1);
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458 narrays -= 1;
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459
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460 #ifdef OBJC_SPARSE3
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461 /* Free bucket table. */
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462 sarray_free_garbage (array->indices);
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463 #else
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464 /* Free bucket table. */
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465 sarray_free_garbage (array->buckets);
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466 #endif
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467
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468 /* If this is a copy of another array, we free it (which might just
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469 decrement its reference count so it will be freed when no longer
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470 in use). */
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471 if (array->is_copy_of)
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472 sarray_free (array->is_copy_of);
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473
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474 /* Free array. */
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|
475 sarray_free_garbage (array);
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476 }
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477
|
|
478 /* This is a lazy copy. Only the core of the structure is actually
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479 copied. */
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480 struct sarray *
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481 sarray_lazy_copy (struct sarray *oarr)
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482 {
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483 struct sarray *arr;
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484
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485 #ifdef OBJC_SPARSE3
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486 size_t num_indices = ((oarr->capacity - 1)/INDEX_CAPACITY) + 1;
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487 struct sindex **new_indices;
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488 #else /* OBJC_SPARSE2 */
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489 size_t num_indices = ((oarr->capacity - 1)/BUCKET_SIZE) + 1;
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490 struct sbucket **new_buckets;
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491 #endif
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492
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493 /* Allocate core array. */
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494 arr = (struct sarray *) objc_malloc (sizeof (struct sarray)); /* !!! */
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495 arr->version.version = oarr->version.version + 1;
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496 #ifdef OBJC_SPARSE3
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497 arr->empty_index = oarr->empty_index;
|
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498 #endif
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499 arr->empty_bucket = oarr->empty_bucket;
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500 arr->ref_count = 1;
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501 oarr->ref_count += 1;
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502 arr->is_copy_of = oarr;
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503 arr->capacity = oarr->capacity;
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|
504
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505 #ifdef OBJC_SPARSE3
|
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506 /* Copy bucket table. */
|
|
507 new_indices = (struct sindex **)
|
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508 objc_malloc (sizeof (struct sindex *) * num_indices);
|
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509 memcpy (new_indices, oarr->indices, sizeof (struct sindex *) * num_indices);
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510 arr->indices = new_indices;
|
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511 #else
|
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512 /* Copy bucket table. */
|
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513 new_buckets = (struct sbucket **)
|
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514 objc_malloc (sizeof (struct sbucket *) * num_indices);
|
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515 memcpy (new_buckets, oarr->buckets, sizeof (struct sbucket *) * num_indices);
|
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516 arr->buckets = new_buckets;
|
|
517 #endif
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518
|
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519 idxsize += num_indices;
|
|
520 narrays += 1;
|
|
521
|
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522 return arr;
|
|
523 }
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