src/gallium/auxiliary/cso_cache/cso_hash.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 VMware, Inc.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28  /*
  29   * Authors:
  30   *   Zack Rusin <zackr@vmware.com>
  31   */
  32
  33 #include "util/u_debug.h"
  34 #include "util/u_memory.h"
  35
  36 #include "cso_hash.h"
  37
  38 #ifndef MAX
  39 #define MAX(a, b) ((a > b) ? (a) : (b))
  40 #endif
  41
  42 static const int MinNumBits = 4;
  43
  44 static const unsigned char prime_deltas[] = {
  45    0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3,  9, 25,  3,
  46    1, 21,  3, 21,  7, 15,  9,  5,  3, 29, 15,  0,  0,  0,  0,  0
  47 };
  48
  49 static int primeForNumBits(int numBits)
  50 {
  51    return (1 << numBits) + prime_deltas[numBits];
  52 }
  53
  54 /*
  55     Returns the smallest integer n such that
  56     primeForNumBits(n) >= hint.
  57 */
  58 static int countBits(int hint)
  59 {
  60    int numBits = 0;
  61    int bits = hint;
  62
  63    while (bits > 1) {
  64       bits >>= 1;
  65       numBits++;
  66    }
  67
  68    if (numBits >= (int)sizeof(prime_deltas)) {
  69       numBits = sizeof(prime_deltas) - 1;
  70    } else if (primeForNumBits(numBits) < hint) {
  71       ++numBits;
  72    }
  73    return numBits;
  74 }
  75
  76 struct cso_node {
  77    struct cso_node *next;
  78    unsigned key;
  79    void *value;
  80 };
  81
  82 struct cso_hash_data {
  83    struct cso_node *fakeNext;
  84    struct cso_node **buckets;
  85    int size;
  86    int nodeSize;
  87    short userNumBits;
  88    short numBits;
  89    int numBuckets;
  90 };
  91
  92 struct cso_hash {
  93    union {
  94       struct cso_hash_data *d;
  95       struct cso_node      *e;
  96    } data;
  97 };
  98
  99 static void *cso_data_allocate_node(struct cso_hash_data *hash)
 100 {
 101    return MALLOC(hash->nodeSize);
 102 }
 103
 104 static void cso_free_node(struct cso_node *node)
 105 {
 106    FREE(node);
 107 }
 108
 109 static struct cso_node *
 110 cso_hash_create_node(struct cso_hash *hash,
 111                       unsigned akey, void *avalue,
 112                       struct cso_node **anextNode)
 113 {
 114    struct cso_node *node = cso_data_allocate_node(hash->data.d);
 115
 116    if (!node)
 117       return NULL;
 118
 119    node->key = akey;
 120    node->value = avalue;
 121
 122    node->next = (struct cso_node*)(*anextNode);
 123    *anextNode = node;
 124    ++hash->data.d->size;
 125    return node;
 126 }
 127
 128 static void cso_data_rehash(struct cso_hash_data *hash, int hint)
 129 {
 130    if (hint < 0) {
 131       hint = countBits(-hint);
 132       if (hint < MinNumBits)
 133          hint = MinNumBits;
 134       hash->userNumBits = (short)hint;
 135       while (primeForNumBits(hint) < (hash->size >> 1))
 136          ++hint;
 137    } else if (hint < MinNumBits) {
 138       hint = MinNumBits;
 139    }
 140
 141    if (hash->numBits != hint) {
 142       struct cso_node *e = (struct cso_node *)(hash);
 143       struct cso_node **oldBuckets = hash->buckets;
 144       int oldNumBuckets = hash->numBuckets;
 145       int  i = 0;
 146
 147       hash->numBits = (short)hint;
 148       hash->numBuckets = primeForNumBits(hint);
 149       hash->buckets = MALLOC(sizeof(struct cso_node*) * hash->numBuckets);
 150       for (i = 0; i < hash->numBuckets; ++i)
 151          hash->buckets[i] = e;
 152
 153       for (i = 0; i < oldNumBuckets; ++i) {
 154          struct cso_node *firstNode = oldBuckets[i];
 155          while (firstNode != e) {
 156             unsigned h = firstNode->key;
 157             struct cso_node *lastNode = firstNode;
 158             struct cso_node *afterLastNode;
 159             struct cso_node **beforeFirstNode;
 160
 161             while (lastNode->next != e && lastNode->next->key == h)
 162                lastNode = lastNode->next;
 163
 164             afterLastNode = lastNode->next;
 165             beforeFirstNode = &hash->buckets[h % hash->numBuckets];
 166             while (*beforeFirstNode != e)
 167                beforeFirstNode = &(*beforeFirstNode)->next;
 168             lastNode->next = *beforeFirstNode;
 169             *beforeFirstNode = firstNode;
 170             firstNode = afterLastNode;
 171          }
 172       }
 173       FREE(oldBuckets);
 174    }
 175 }
 176
 177 static void cso_data_might_grow(struct cso_hash_data *hash)
 178 {
 179    if (hash->size >= hash->numBuckets)
 180       cso_data_rehash(hash, hash->numBits + 1);
 181 }
 182
 183 static void cso_data_has_shrunk(struct cso_hash_data *hash)
 184 {
 185    if (hash->size <= (hash->numBuckets >> 3) &&
 186        hash->numBits > hash->userNumBits) {
 187       int max = MAX(hash->numBits-2, hash->userNumBits);
 188       cso_data_rehash(hash,  max);
 189    }
 190 }
 191
 192 static struct cso_node *cso_data_first_node(struct cso_hash_data *hash)
 193 {
 194    struct cso_node *e = (struct cso_node *)(hash);
 195    struct cso_node **bucket = hash->buckets;
 196    int n = hash->numBuckets;
 197    while (n--) {
 198       if (*bucket != e)
 199          return *bucket;
 200       ++bucket;
 201    }
 202    return e;
 203 }
 204
 205 static struct cso_node **cso_hash_find_node(struct cso_hash *hash, unsigned akey)
 206 {
 207    struct cso_node **node;
 208
 209    if (hash->data.d->numBuckets) {
 210       node = (struct cso_node **)(&hash->data.d->buckets[akey % hash->data.d->numBuckets]);
 211       assert(*node == hash->data.e || (*node)->next);
 212       while (*node != hash->data.e && (*node)->key != akey)
 213          node = &(*node)->next;
 214    } else {
 215       node = (struct cso_node **)((const struct cso_node * const *)(&hash->data.e));
 216    }
 217    return node;
 218 }
 219
 220 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash,
 221                                        unsigned key, void *data)
 222 {
 223    cso_data_might_grow(hash->data.d);
 224
 225    {
 226       struct cso_node **nextNode = cso_hash_find_node(hash, key);
 227       struct cso_node *node = cso_hash_create_node(hash, key, data, nextNode);
 228       if (!node) {
 229          struct cso_hash_iter null_iter = {hash, 0};
 230          return null_iter;
 231       }
 232
 233       {
 234          struct cso_hash_iter iter = {hash, node};
 235          return iter;
 236       }
 237    }
 238 }
 239
 240 struct cso_hash * cso_hash_create(void)
 241 {
 242    struct cso_hash *hash = MALLOC_STRUCT(cso_hash);
 243    if (!hash)
 244       return NULL;
 245
 246    hash->data.d = MALLOC_STRUCT(cso_hash_data);
 247    if (!hash->data.d) {
 248       FREE(hash);
 249       return NULL;
 250    }
 251
 252    hash->data.d->fakeNext = 0;
 253    hash->data.d->buckets = 0;
 254    hash->data.d->size = 0;
 255    hash->data.d->nodeSize = sizeof(struct cso_node);
 256    hash->data.d->userNumBits = (short)MinNumBits;
 257    hash->data.d->numBits = 0;
 258    hash->data.d->numBuckets = 0;
 259
 260    return hash;
 261 }
 262
 263 void cso_hash_delete(struct cso_hash *hash)
 264 {
 265    struct cso_node *e_for_x = (struct cso_node *)(hash->data.d);
 266    struct cso_node **bucket = (struct cso_node **)(hash->data.d->buckets);
 267    int n = hash->data.d->numBuckets;
 268    while (n--) {
 269       struct cso_node *cur = *bucket++;
 270       while (cur != e_for_x) {
 271          struct cso_node *next = cur->next;
 272          cso_free_node(cur);
 273          cur = next;
 274       }
 275    }
 276    FREE(hash->data.d->buckets);
 277    FREE(hash->data.d);
 278    FREE(hash);
 279 }
 280
 281 struct cso_hash_iter cso_hash_find(struct cso_hash *hash,
 282                                      unsigned key)
 283 {
 284    struct cso_node **nextNode = cso_hash_find_node(hash, key);
 285    struct cso_hash_iter iter = {hash, *nextNode};
 286    return iter;
 287 }
 288
 289 unsigned cso_hash_iter_key(struct cso_hash_iter iter)
 290 {
 291    if (!iter.node || iter.hash->data.e == iter.node)
 292       return 0;
 293    return iter.node->key;
 294 }
 295
 296 void * cso_hash_iter_data(struct cso_hash_iter iter)
 297 {
 298    if (!iter.node || iter.hash->data.e == iter.node)
 299       return 0;
 300    return iter.node->value;
 301 }
 302
 303 static struct cso_node *cso_hash_data_next(struct cso_node *node)
 304 {
 305    union {
 306       struct cso_node *next;
 307       struct cso_node *e;
 308       struct cso_hash_data *d;
 309    } a;
 310    int start;
 311    struct cso_node **bucket;
 312    int n;
 313
 314    a.next = node->next;
 315    if (!a.next) {
 316       debug_printf("iterating beyond the last element\n");
 317       return 0;
 318    }
 319    if (a.next->next)
 320       return a.next;
 321
 322    start = (node->key % a.d->numBuckets) + 1;
 323    bucket = a.d->buckets + start;
 324    n = a.d->numBuckets - start;
 325    while (n--) {
 326       if (*bucket != a.e)
 327          return *bucket;
 328       ++bucket;
 329    }
 330    return a.e;
 331 }
 332
 333
 334 static struct cso_node *cso_hash_data_prev(struct cso_node *node)
 335 {
 336    union {
 337       struct cso_node *e;
 338       struct cso_hash_data *d;
 339    } a;
 340    int start;
 341    struct cso_node *sentinel;
 342    struct cso_node **bucket;
 343
 344    a.e = node;
 345    while (a.e->next)
 346       a.e = a.e->next;
 347
 348    if (node == a.e)
 349       start = a.d->numBuckets - 1;
 350    else
 351       start = node->key % a.d->numBuckets;
 352
 353    sentinel = node;
 354    bucket = a.d->buckets + start;
 355    while (start >= 0) {
 356       if (*bucket != sentinel) {
 357          struct cso_node *prev = *bucket;
 358          while (prev->next != sentinel)
 359             prev = prev->next;
 360          return prev;
 361       }
 362
 363       sentinel = a.e;
 364       --bucket;
 365       --start;
 366    }
 367    debug_printf("iterating backward beyond first element\n");
 368    return a.e;
 369 }
 370
 371 struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter)
 372 {
 373    struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
 374    return next;
 375 }
 376
 377 int cso_hash_iter_is_null(struct cso_hash_iter iter)
 378 {
 379    if (!iter.node || iter.node == iter.hash->data.e)
 380       return 1;
 381    return 0;
 382 }
 383
 384 void * cso_hash_take(struct cso_hash *hash,
 385                       unsigned akey)
 386 {
 387    struct cso_node **node = cso_hash_find_node(hash, akey);
 388    if (*node != hash->data.e) {
 389       void *t = (*node)->value;
 390       struct cso_node *next = (*node)->next;
 391       cso_free_node(*node);
 392       *node = next;
 393       --hash->data.d->size;
 394       cso_data_has_shrunk(hash->data.d);
 395       return t;
 396    }
 397    return 0;
 398 }
 399
 400 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter)
 401 {
 402    struct cso_hash_iter prev = {iter.hash,
 403                                  cso_hash_data_prev(iter.node)};
 404    return prev;
 405 }
 406
 407 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash)
 408 {
 409    struct cso_hash_iter iter = {hash, cso_data_first_node(hash->data.d)};
 410    return iter;
 411 }
 412
 413 int cso_hash_size(struct cso_hash *hash)
 414 {
 415    return hash->data.d->size;
 416 }
 417
 418 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter)
 419 {
 420    struct cso_hash_iter ret = iter;
 421    struct cso_node *node = iter.node;
 422    struct cso_node **node_ptr;
 423
 424    if (node == hash->data.e)
 425       return iter;
 426
 427    ret = cso_hash_iter_next(ret);
 428    node_ptr = (struct cso_node**)(&hash->data.d->buckets[node->key % hash->data.d->numBuckets]);
 429    while (*node_ptr != node)
 430       node_ptr = &(*node_ptr)->next;
 431    *node_ptr = node->next;
 432    cso_free_node(node);
 433    --hash->data.d->size;
 434    return ret;
 435 }
 436
 437 boolean cso_hash_contains(struct cso_hash *hash, unsigned key)
 438 {
 439    struct cso_node **node = cso_hash_find_node(hash, key);
 440    return (*node != hash->data.e);
 441 }