src/gallium/auxiliary/cso_cache/cso_hash.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   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 TUNGSTEN GRAPHICS 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 <zack@tungstengraphics.com>
  31   */
  32
  33 #include "cso_hash.h"
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <assert.h>
  39
  40 #define MAX(a, b) ((a > b) ? (a) : (b))
  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_data_free_node(struct cso_node *node)
 105 {
 106    /* XXX still a leak here.
 107     * Need to cast value ptr to original cso type, then free the
 108     * driver-specific data hanging off of it.  For example:
 109    struct cso_sampler *csamp = (struct cso_sampler *) node->value;
 110    free(csamp->data);
 111    */
 112    free(node->value);
 113    free(node);
 114 }
 115
 116 static struct cso_node *
 117 cso_hash_create_node(struct cso_hash *hash,
 118                       unsigned akey, void *avalue,
 119                       struct cso_node **anextNode)
 120 {
 121    struct cso_node *node = cso_data_allocate_node(hash->data.d);
 122    node->key = akey;
 123    node->value = avalue;
 124
 125    node->next = (struct cso_node*)(*anextNode);
 126    *anextNode = node;
 127    ++hash->data.d->size;
 128    return node;
 129 }
 130
 131 static void cso_data_rehash(struct cso_hash_data *hash, int hint)
 132 {
 133    if (hint < 0) {
 134       hint = countBits(-hint);
 135       if (hint < MinNumBits)
 136          hint = MinNumBits;
 137       hash->userNumBits = hint;
 138       while (primeForNumBits(hint) < (hash->size >> 1))
 139          ++hint;
 140    } else if (hint < MinNumBits) {
 141       hint = MinNumBits;
 142    }
 143
 144    if (hash->numBits != hint) {
 145       struct cso_node *e = (struct cso_node *)(hash);
 146       struct cso_node **oldBuckets = hash->buckets;
 147       int oldNumBuckets = hash->numBuckets;
 148       int  i = 0;
 149
 150       hash->numBits = hint;
 151       hash->numBuckets = primeForNumBits(hint);
 152       hash->buckets = malloc(sizeof(struct cso_node*) * hash->numBuckets);
 153       for (i = 0; i < hash->numBuckets; ++i)
 154          hash->buckets[i] = e;
 155
 156       for (i = 0; i < oldNumBuckets; ++i) {
 157          struct cso_node *firstNode = oldBuckets[i];
 158          while (firstNode != e) {
 159             unsigned h = firstNode->key;
 160             struct cso_node *lastNode = firstNode;
 161             while (lastNode->next != e && lastNode->next->key == h)
 162                lastNode = lastNode->next;
 163
 164             struct cso_node *afterLastNode = lastNode->next;
 165             struct cso_node **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    struct cso_node **nextNode = cso_hash_find_node(hash, key);
 226    struct cso_node *node = cso_hash_create_node(hash, key, data, nextNode);
 227    struct cso_hash_iter iter = {hash, node};
 228    return iter;
 229 }
 230
 231 struct cso_hash * cso_hash_create(void)
 232 {
 233    struct cso_hash *hash = malloc(sizeof(struct cso_hash));
 234    hash->data.d = malloc(sizeof(struct cso_hash_data));
 235    hash->data.d->fakeNext = 0;
 236    hash->data.d->buckets = 0;
 237    hash->data.d->size = 0;
 238    hash->data.d->nodeSize = sizeof(struct cso_node);
 239    hash->data.d->userNumBits = MinNumBits;
 240    hash->data.d->numBits = 0;
 241    hash->data.d->numBuckets = 0;
 242
 243    return hash;
 244 }
 245
 246 void cso_hash_delete(struct cso_hash *hash)
 247 {
 248    struct cso_node *e_for_x = (struct cso_node *)(hash->data.d);
 249    struct cso_node **bucket = (struct cso_node **)(hash->data.d->buckets);
 250    int n = hash->data.d->numBuckets;
 251    while (n--) {
 252       struct cso_node *cur = *bucket++;
 253       while (cur != e_for_x) {
 254          struct cso_node *next = cur->next;
 255          cso_data_free_node(cur);
 256          cur = next;
 257       }
 258    }
 259    free(hash->data.d->buckets);
 260    free(hash->data.d);
 261    free(hash);
 262 }
 263
 264 struct cso_hash_iter cso_hash_find(struct cso_hash *hash,
 265                                      unsigned key)
 266 {
 267    struct cso_node **nextNode = cso_hash_find_node(hash, key);
 268    struct cso_hash_iter iter = {hash, *nextNode};
 269    return iter;
 270 }
 271
 272 unsigned cso_hash_iter_key(struct cso_hash_iter iter)
 273 {
 274    if (!iter.node || iter.hash->data.e == iter.node)
 275       return 0;
 276    return iter.node->key;
 277 }
 278
 279 void * cso_hash_iter_data(struct cso_hash_iter iter)
 280 {
 281    if (!iter.node || iter.hash->data.e == iter.node)
 282       return 0;
 283    return iter.node->value;
 284 }
 285
 286 static struct cso_node *cso_hash_data_next(struct cso_node *node)
 287 {
 288    union {
 289       struct cso_node *next;
 290       struct cso_node *e;
 291       struct cso_hash_data *d;
 292    } a;
 293    a.next = node->next;
 294    if (!a.next) {
 295       fprintf(stderr, "iterating beyond the last element\n");
 296       return 0;
 297    }
 298    if (a.next->next)
 299       return a.next;
 300
 301    int start = (node->key % a.d->numBuckets) + 1;
 302    struct cso_node **bucket = a.d->buckets + start;
 303    int n = a.d->numBuckets - start;
 304    while (n--) {
 305       if (*bucket != a.e)
 306          return *bucket;
 307       ++bucket;
 308    }
 309    return a.e;
 310 }
 311
 312
 313 static struct cso_node *cso_hash_data_prev(struct cso_node *node)
 314 {
 315    union {
 316       struct cso_node *e;
 317       struct cso_hash_data *d;
 318    } a;
 319
 320    a.e = node;
 321    while (a.e->next)
 322       a.e = a.e->next;
 323
 324    int start;
 325    if (node == a.e)
 326       start = a.d->numBuckets - 1;
 327    else
 328       start = node->key % a.d->numBuckets;
 329
 330    struct cso_node *sentinel = node;
 331    struct cso_node **bucket = a.d->buckets + start;
 332    while (start >= 0) {
 333       if (*bucket != sentinel) {
 334          struct cso_node *prev = *bucket;
 335          while (prev->next != sentinel)
 336             prev = prev->next;
 337          return prev;
 338       }
 339
 340       sentinel = a.e;
 341       --bucket;
 342       --start;
 343    }
 344    fprintf(stderr, "iterating backward beyond first element\n");
 345    return a.e;
 346 }
 347
 348 struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter)
 349 {
 350    struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
 351    return next;
 352 }
 353
 354 int cso_hash_iter_is_null(struct cso_hash_iter iter)
 355 {
 356    if (!iter.node || iter.node == iter.hash->data.e)
 357       return 1;
 358    return 0;
 359 }
 360
 361 void * cso_hash_take(struct cso_hash *hash,
 362                       unsigned akey)
 363 {
 364    struct cso_node **node = cso_hash_find_node(hash, akey);
 365    if (*node != hash->data.e) {
 366       void *t = (*node)->value;
 367       struct cso_node *next = (*node)->next;
 368       cso_data_free_node(*node);
 369       *node = next;
 370       --hash->data.d->size;
 371       cso_data_has_shrunk(hash->data.d);
 372       return t;
 373    }
 374    return 0;
 375 }
 376
 377 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter)
 378 {
 379    struct cso_hash_iter prev = {iter.hash,
 380                                  cso_hash_data_prev(iter.node)};
 381    return prev;
 382 }
 383
 384 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash)
 385 {
 386    struct cso_hash_iter iter = {hash, cso_data_first_node(hash->data.d)};
 387    return iter;
 388 }