Ulrich Drepper | b08d5a8 | 2005-07-26 05:00:05 +0000 | [diff] [blame^] | 1 | /* Copyright (C) 2000, 2001, 2002, 2005 Red Hat, Inc. |
| 2 | Written by Ulrich Drepper <drepper@redhat.com>, 2000. |
| 3 | |
| 4 | This program is Open Source software; you can redistribute it and/or |
| 5 | modify it under the terms of the Open Software License version 1.0 as |
| 6 | published by the Open Source Initiative. |
| 7 | |
| 8 | You should have received a copy of the Open Software License along |
| 9 | with this program; if not, you may obtain a copy of the Open Software |
| 10 | License version 1.0 from http://www.opensource.org/licenses/osl.php or |
| 11 | by writing the Open Source Initiative c/o Lawrence Rosen, Esq., |
| 12 | 3001 King Ranch Road, Ukiah, CA 95482. */ |
| 13 | |
| 14 | #include <assert.h> |
| 15 | #include <stdlib.h> |
| 16 | #include <system.h> |
| 17 | |
| 18 | /* Before including this file the following macros must be defined: |
| 19 | |
| 20 | NAME name of the hash table structure. |
| 21 | TYPE data type of the hash table entries |
| 22 | COMPARE comparison function taking two pointers to TYPE objects |
| 23 | |
| 24 | The following macros if present select features: |
| 25 | |
| 26 | ITERATE iterating over the table entries is possible |
| 27 | REVERSE iterate in reverse order of insert |
| 28 | */ |
| 29 | |
| 30 | |
| 31 | static size_t |
| 32 | lookup (htab, hval, val) |
| 33 | NAME *htab; |
| 34 | unsigned long int hval; |
| 35 | TYPE val __attribute__ ((unused)); |
| 36 | { |
| 37 | /* First hash function: simply take the modul but prevent zero. */ |
| 38 | size_t idx = 1 + hval % htab->size; |
| 39 | |
| 40 | if (htab->table[idx].hashval != 0) |
| 41 | { |
| 42 | unsigned long int hash; |
| 43 | |
| 44 | if (htab->table[idx].hashval == hval |
| 45 | && COMPARE (htab->table[idx].data, val) == 0) |
| 46 | return idx; |
| 47 | |
| 48 | /* Second hash function as suggested in [Knuth]. */ |
| 49 | hash = 1 + hval % (htab->size - 2); |
| 50 | |
| 51 | do |
| 52 | { |
| 53 | if (idx <= hash) |
| 54 | idx = htab->size + idx - hash; |
| 55 | else |
| 56 | idx -= hash; |
| 57 | |
| 58 | /* If entry is found use it. */ |
| 59 | if (htab->table[idx].hashval == hval |
| 60 | && COMPARE (htab->table[idx].data, val) == 0) |
| 61 | return idx; |
| 62 | } |
| 63 | while (htab->table[idx].hashval); |
| 64 | } |
| 65 | return idx; |
| 66 | } |
| 67 | |
| 68 | |
| 69 | static void |
| 70 | insert_entry_2 (NAME *htab, unsigned long int hval, size_t idx, TYPE data) |
| 71 | { |
| 72 | #ifdef ITERATE |
| 73 | if (htab->table[idx].hashval == 0) |
| 74 | { |
| 75 | # ifdef REVERSE |
| 76 | htab->table[idx].next = htab->first; |
| 77 | htab->first = &htab->table[idx]; |
| 78 | # else |
| 79 | /* Add the new value to the list. */ |
| 80 | if (htab->first == NULL) |
| 81 | htab->first = htab->table[idx].next = &htab->table[idx]; |
| 82 | else |
| 83 | { |
| 84 | htab->table[idx].next = htab->first->next; |
| 85 | htab->first = htab->first->next = &htab->table[idx]; |
| 86 | } |
| 87 | # endif |
| 88 | } |
| 89 | #endif |
| 90 | |
| 91 | htab->table[idx].hashval = hval; |
| 92 | htab->table[idx].data = data; |
| 93 | |
| 94 | ++htab->filled; |
| 95 | if (100 * htab->filled > 90 * htab->size) |
| 96 | { |
| 97 | /* Table is filled more than 90%. Resize the table. */ |
| 98 | #ifdef ITERATE |
| 99 | __typeof__ (htab->first) first; |
| 100 | # ifndef REVERSE |
| 101 | __typeof__ (htab->first) runp; |
| 102 | # endif |
| 103 | #else |
| 104 | unsigned long int old_size = htab->size; |
| 105 | #endif |
| 106 | #define _TABLE(name) \ |
| 107 | name##_ent *table = htab->table |
| 108 | #define TABLE(name) _TABLE (name) |
| 109 | TABLE(NAME); |
| 110 | |
| 111 | htab->size = next_prime (htab->size * 2); |
| 112 | htab->filled = 0; |
| 113 | #ifdef ITERATE |
| 114 | first = htab->first; |
| 115 | htab->first = NULL; |
| 116 | #endif |
| 117 | htab->table = calloc ((1 + htab->size), sizeof (htab->table[0])); |
| 118 | if (htab->table == NULL) |
| 119 | { |
| 120 | /* We cannot enlarge the table. Live with what we got. This |
| 121 | might lead to an infinite loop at some point, though. */ |
| 122 | htab->table = table; |
| 123 | return; |
| 124 | } |
| 125 | |
| 126 | /* Add the old entries to the new table. When iteration is |
| 127 | supported we maintain the order. */ |
| 128 | #ifdef ITERATE |
| 129 | # ifdef REVERSE |
| 130 | while (first != NULL) |
| 131 | { |
| 132 | insert_entry_2 (htab, first->hashval, |
| 133 | lookup (htab, first->hashval, first->data), |
| 134 | first->data); |
| 135 | |
| 136 | first = first->next; |
| 137 | } |
| 138 | # else |
| 139 | assert (first != NULL); |
| 140 | runp = first = first->next; |
| 141 | do |
| 142 | insert_entry_2 (htab, runp->hashval, |
| 143 | lookup (htab, runp->hashval, runp->data), runp->data); |
| 144 | while ((runp = runp->next) != first); |
| 145 | # endif |
| 146 | #else |
| 147 | for (idx = 1; idx <= old_size; ++idx) |
| 148 | if (table[idx].hashval != 0) |
| 149 | insert_entry_2 (htab, table[idx].hashval, |
| 150 | lookup (htab, table[idx].hashval, table[idx].data), |
| 151 | table[idx].data); |
| 152 | #endif |
| 153 | |
| 154 | free (table); |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | |
| 159 | int |
| 160 | #define INIT(name) _INIT (name) |
| 161 | #define _INIT(name) \ |
| 162 | name##_init |
| 163 | INIT(NAME) (htab, init_size) |
| 164 | NAME *htab; |
| 165 | unsigned long int init_size; |
| 166 | { |
| 167 | /* We need the size to be a prime. */ |
| 168 | init_size = next_prime (init_size); |
| 169 | |
| 170 | /* Initialize the data structure. */ |
| 171 | htab->size = init_size; |
| 172 | htab->filled = 0; |
| 173 | #ifdef ITERATE |
| 174 | htab->first = NULL; |
| 175 | #endif |
| 176 | htab->table = (void *) calloc ((init_size + 1), sizeof (htab->table[0])); |
| 177 | if (htab->table == NULL) |
| 178 | return -1; |
| 179 | |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | |
| 184 | int |
| 185 | #define FREE(name) _FREE (name) |
| 186 | #define _FREE(name) \ |
| 187 | name##_free |
| 188 | FREE(NAME) (htab) |
| 189 | NAME *htab; |
| 190 | { |
| 191 | free (htab->table); |
| 192 | return 0; |
| 193 | } |
| 194 | |
| 195 | |
| 196 | int |
| 197 | #define INSERT(name) _INSERT (name) |
| 198 | #define _INSERT(name) \ |
| 199 | name##_insert |
| 200 | INSERT(NAME) (htab, hval, data) |
| 201 | NAME *htab; |
| 202 | unsigned long int hval; |
| 203 | TYPE data; |
| 204 | { |
| 205 | size_t idx; |
| 206 | |
| 207 | /* Make the hash value nonzero. */ |
| 208 | hval = hval ?: 1; |
| 209 | |
| 210 | idx = lookup (htab, hval, data); |
| 211 | |
| 212 | if (htab->table[idx].hashval != 0) |
| 213 | /* We don't want to overwrite the old value. */ |
| 214 | return -1; |
| 215 | |
| 216 | /* An empty bucket has been found. */ |
| 217 | insert_entry_2 (htab, hval, idx, data); |
| 218 | return 0; |
| 219 | } |
| 220 | |
| 221 | |
| 222 | #ifdef OVERWRITE |
| 223 | int |
| 224 | #define INSERT(name) _INSERT (name) |
| 225 | #define _INSERT(name) \ |
| 226 | name##_overwrite |
| 227 | INSERT(NAME) (htab, hval, data) |
| 228 | NAME *htab; |
| 229 | unsigned long int hval; |
| 230 | TYPE data; |
| 231 | { |
| 232 | size_t idx; |
| 233 | |
| 234 | /* Make the hash value nonzero. */ |
| 235 | hval = hval ?: 1; |
| 236 | |
| 237 | idx = lookup (htab, hval, data); |
| 238 | |
| 239 | /* The correct bucket has been found. */ |
| 240 | insert_entry_2 (htab, hval, idx, data); |
| 241 | return 0; |
| 242 | } |
| 243 | #endif |
| 244 | |
| 245 | |
| 246 | TYPE |
| 247 | #define FIND(name) _FIND (name) |
| 248 | #define _FIND(name) \ |
| 249 | name##_find |
| 250 | FIND(NAME) (htab, hval, val) |
| 251 | NAME *htab; |
| 252 | unsigned long int hval; |
| 253 | TYPE val; |
| 254 | { |
| 255 | size_t idx; |
| 256 | |
| 257 | /* Make the hash value nonzero. */ |
| 258 | hval = hval ?: 1; |
| 259 | |
| 260 | idx = lookup (htab, hval, val); |
| 261 | |
| 262 | if (htab->table[idx].hashval == 0) |
| 263 | return NULL; |
| 264 | |
| 265 | return htab->table[idx].data; |
| 266 | } |
| 267 | |
| 268 | |
| 269 | #ifdef ITERATE |
| 270 | # define ITERATEFCT(name) _ITERATEFCT (name) |
| 271 | # define _ITERATEFCT(name) \ |
| 272 | name##_iterate |
| 273 | TYPE |
| 274 | ITERATEFCT(NAME) (htab, ptr) |
| 275 | NAME *htab; |
| 276 | void **ptr; |
| 277 | { |
| 278 | void *p = *ptr; |
| 279 | |
| 280 | # define TYPENAME(name) _TYPENAME (name) |
| 281 | # define _TYPENAME(name) name##_ent |
| 282 | |
| 283 | # ifdef REVERSE |
| 284 | if (p == NULL) |
| 285 | p = htab->first; |
| 286 | else |
| 287 | p = ((TYPENAME(NAME) *) p)->next; |
| 288 | |
| 289 | if (p == NULL) |
| 290 | { |
| 291 | *ptr = NULL; |
| 292 | return NULL; |
| 293 | } |
| 294 | # else |
| 295 | if (p == NULL) |
| 296 | { |
| 297 | if (htab->first == NULL) |
| 298 | return NULL; |
| 299 | p = htab->first->next; |
| 300 | } |
| 301 | else |
| 302 | { |
| 303 | if (p == htab->first) |
| 304 | return NULL; |
| 305 | |
| 306 | p = ((TYPENAME(NAME) *) p)->next; |
| 307 | } |
| 308 | # endif |
| 309 | |
| 310 | /* Prepare the next element. If possible this will pull the data |
| 311 | into the cache, for reading. */ |
| 312 | __builtin_prefetch (((TYPENAME(NAME) *) p)->next, 0, 2); |
| 313 | |
| 314 | return ((TYPENAME(NAME) *) (*ptr = p))->data; |
| 315 | } |
| 316 | #endif |