crypto/lhash/lhash.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <stdlib.h>
  13 #include <openssl/crypto.h>
  14 #include <openssl/lhash.h>
  15 #include "lhash_lcl.h"
  16
  17
  18 #undef MIN_NODES
  19 #define MIN_NODES       16
  20 #define UP_LOAD         (2*LH_LOAD_MULT) /* load times 256 (default 2) */
  21 #define DOWN_LOAD       (LH_LOAD_MULT) /* load times 256 (default 1) */
  22
  23 static void expand(OPENSSL_LHASH *lh);
  24 static void contract(OPENSSL_LHASH *lh);
  25 static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh, const void *data, unsigned long *rhash);
  26
  27 OPENSSL_LHASH *OPENSSL_LH_new(OPENSSL_LH_HASHFUNC h, OPENSSL_LH_COMPFUNC c)
  28 {
  29     OPENSSL_LHASH *ret;
  30
  31     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL)
  32         goto err0;
  33     if ((ret->b = OPENSSL_zalloc(sizeof(*ret->b) * MIN_NODES)) == NULL)
  34         goto err1;
  35     ret->comp = ((c == NULL) ? (OPENSSL_LH_COMPFUNC)strcmp : c);
  36     ret->hash = ((h == NULL) ? (OPENSSL_LH_HASHFUNC)OPENSSL_LH_strhash : h);
  37     ret->num_nodes = MIN_NODES / 2;
  38     ret->num_alloc_nodes = MIN_NODES;
  39     ret->pmax = MIN_NODES / 2;
  40     ret->up_load = UP_LOAD;
  41     ret->down_load = DOWN_LOAD;
  42     return (ret);
  43
  44  err1:
  45     OPENSSL_free(ret);
  46  err0:
  47     return (NULL);
  48 }
  49
  50 void OPENSSL_LH_free(OPENSSL_LHASH *lh)
  51 {
  52     unsigned int i;
  53     OPENSSL_LH_NODE *n, *nn;
  54
  55     if (lh == NULL)
  56         return;
  57
  58     for (i = 0; i < lh->num_nodes; i++) {
  59         n = lh->b[i];
  60         while (n != NULL) {
  61             nn = n->next;
  62             OPENSSL_free(n);
  63             n = nn;
  64         }
  65     }
  66     OPENSSL_free(lh->b);
  67     OPENSSL_free(lh);
  68 }
  69
  70 void *OPENSSL_LH_insert(OPENSSL_LHASH *lh, void *data)
  71 {
  72     unsigned long hash;
  73     OPENSSL_LH_NODE *nn, **rn;
  74     void *ret;
  75
  76     lh->error = 0;
  77     if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes))
  78         expand(lh);
  79
  80     rn = getrn(lh, data, &hash);
  81
  82     if (*rn == NULL) {
  83         if ((nn = OPENSSL_malloc(sizeof(*nn))) == NULL) {
  84             lh->error++;
  85             return (NULL);
  86         }
  87         nn->data = data;
  88         nn->next = NULL;
  89         nn->hash = hash;
  90         *rn = nn;
  91         ret = NULL;
  92         lh->num_insert++;
  93         lh->num_items++;
  94     } else {                    /* replace same key */
  95
  96         ret = (*rn)->data;
  97         (*rn)->data = data;
  98         lh->num_replace++;
  99     }
 100     return (ret);
 101 }
 102
 103 void *OPENSSL_LH_delete(OPENSSL_LHASH *lh, const void *data)
 104 {
 105     unsigned long hash;
 106     OPENSSL_LH_NODE *nn, **rn;
 107     void *ret;
 108
 109     lh->error = 0;
 110     rn = getrn(lh, data, &hash);
 111
 112     if (*rn == NULL) {
 113         lh->num_no_delete++;
 114         return (NULL);
 115     } else {
 116         nn = *rn;
 117         *rn = nn->next;
 118         ret = nn->data;
 119         OPENSSL_free(nn);
 120         lh->num_delete++;
 121     }
 122
 123     lh->num_items--;
 124     if ((lh->num_nodes > MIN_NODES) &&
 125         (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
 126         contract(lh);
 127
 128     return (ret);
 129 }
 130
 131 void *OPENSSL_LH_retrieve(OPENSSL_LHASH *lh, const void *data)
 132 {
 133     unsigned long hash;
 134     OPENSSL_LH_NODE **rn;
 135     void *ret;
 136
 137     lh->error = 0;
 138     rn = getrn(lh, data, &hash);
 139
 140     if (*rn == NULL) {
 141         lh->num_retrieve_miss++;
 142         return (NULL);
 143     } else {
 144         ret = (*rn)->data;
 145         lh->num_retrieve++;
 146     }
 147     return (ret);
 148 }
 149
 150 static void doall_util_fn(OPENSSL_LHASH *lh, int use_arg,
 151                           OPENSSL_LH_DOALL_FUNC func,
 152                           OPENSSL_LH_DOALL_FUNCARG func_arg, void *arg)
 153 {
 154     int i;
 155     OPENSSL_LH_NODE *a, *n;
 156
 157     if (lh == NULL)
 158         return;
 159
 160     /*
 161      * reverse the order so we search from 'top to bottom' We were having
 162      * memory leaks otherwise
 163      */
 164     for (i = lh->num_nodes - 1; i >= 0; i--) {
 165         a = lh->b[i];
 166         while (a != NULL) {
 167             n = a->next;
 168             if (use_arg)
 169                 func_arg(a->data, arg);
 170             else
 171                 func(a->data);
 172             a = n;
 173         }
 174     }
 175 }
 176
 177 void OPENSSL_LH_doall(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNC func)
 178 {
 179     doall_util_fn(lh, 0, func, (OPENSSL_LH_DOALL_FUNCARG)0, NULL);
 180 }
 181
 182 void OPENSSL_LH_doall_arg(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNCARG func, void *arg)
 183 {
 184     doall_util_fn(lh, 1, (OPENSSL_LH_DOALL_FUNC)0, func, arg);
 185 }
 186
 187 static void expand(OPENSSL_LHASH *lh)
 188 {
 189     OPENSSL_LH_NODE **n, **n1, **n2, *np;
 190     unsigned int p, i, j;
 191     unsigned long hash, nni;
 192
 193     lh->num_nodes++;
 194     lh->num_expands++;
 195     p = (int)lh->p++;
 196     n1 = &(lh->b[p]);
 197     n2 = &(lh->b[p + (int)lh->pmax]);
 198     *n2 = NULL;
 199     nni = lh->num_alloc_nodes;
 200
 201     for (np = *n1; np != NULL;) {
 202         hash = np->hash;
 203         if ((hash % nni) != p) { /* move it */
 204             *n1 = (*n1)->next;
 205             np->next = *n2;
 206             *n2 = np;
 207         } else
 208             n1 = &((*n1)->next);
 209         np = *n1;
 210     }
 211
 212     if ((lh->p) >= lh->pmax) {
 213         j = (int)lh->num_alloc_nodes * 2;
 214         n = OPENSSL_realloc(lh->b, (int)(sizeof(OPENSSL_LH_NODE *) * j));
 215         if (n == NULL) {
 216             /* fputs("realloc error in lhash",stderr); */
 217             lh->error++;
 218             lh->p = 0;
 219             return;
 220         }
 221         for (i = (int)lh->num_alloc_nodes; i < j; i++) /* 26/02/92 eay */
 222             n[i] = NULL;        /* 02/03/92 eay */
 223         lh->pmax = lh->num_alloc_nodes;
 224         lh->num_alloc_nodes = j;
 225         lh->num_expand_reallocs++;
 226         lh->p = 0;
 227         lh->b = n;
 228     }
 229 }
 230
 231 static void contract(OPENSSL_LHASH *lh)
 232 {
 233     OPENSSL_LH_NODE **n, *n1, *np;
 234
 235     np = lh->b[lh->p + lh->pmax - 1];
 236     lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
 237     if (lh->p == 0) {
 238         n = OPENSSL_realloc(lh->b,
 239                             (unsigned int)(sizeof(OPENSSL_LH_NODE *) * lh->pmax));
 240         if (n == NULL) {
 241             /* fputs("realloc error in lhash",stderr); */
 242             lh->error++;
 243             return;
 244         }
 245         lh->num_contract_reallocs++;
 246         lh->num_alloc_nodes /= 2;
 247         lh->pmax /= 2;
 248         lh->p = lh->pmax - 1;
 249         lh->b = n;
 250     } else
 251         lh->p--;
 252
 253     lh->num_nodes--;
 254     lh->num_contracts++;
 255
 256     n1 = lh->b[(int)lh->p];
 257     if (n1 == NULL)
 258         lh->b[(int)lh->p] = np;
 259     else {
 260         while (n1->next != NULL)
 261             n1 = n1->next;
 262         n1->next = np;
 263     }
 264 }
 265
 266 static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh,
 267                                const void *data, unsigned long *rhash)
 268 {
 269     OPENSSL_LH_NODE **ret, *n1;
 270     unsigned long hash, nn;
 271     OPENSSL_LH_COMPFUNC cf;
 272
 273     hash = (*(lh->hash)) (data);
 274     lh->num_hash_calls++;
 275     *rhash = hash;
 276
 277     nn = hash % lh->pmax;
 278     if (nn < lh->p)
 279         nn = hash % lh->num_alloc_nodes;
 280
 281     cf = lh->comp;
 282     ret = &(lh->b[(int)nn]);
 283     for (n1 = *ret; n1 != NULL; n1 = n1->next) {
 284         lh->num_hash_comps++;
 285         if (n1->hash != hash) {
 286             ret = &(n1->next);
 287             continue;
 288         }
 289         lh->num_comp_calls++;
 290         if (cf(n1->data, data) == 0)
 291             break;
 292         ret = &(n1->next);
 293     }
 294     return (ret);
 295 }
 296
 297 /*
 298  * The following hash seems to work very well on normal text strings no
 299  * collisions on /usr/dict/words and it distributes on %2^n quite well, not
 300  * as good as MD5, but still good.
 301  */
 302 unsigned long OPENSSL_LH_strhash(const char *c)
 303 {
 304     unsigned long ret = 0;
 305     long n;
 306     unsigned long v;
 307     int r;
 308
 309     if ((c == NULL) || (*c == '\0'))
 310         return (ret);
 311 /*-
 312     unsigned char b[16];
 313     MD5(c,strlen(c),b);
 314     return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
 315 */
 316
 317     n = 0x100;
 318     while (*c) {
 319         v = n | (*c);
 320         n += 0x100;
 321         r = (int)((v >> 2) ^ v) & 0x0f;
 322         ret = (ret << r) | (ret >> (32 - r));
 323         ret &= 0xFFFFFFFFL;
 324         ret ^= v * v;
 325         c++;
 326     }
 327     return ((ret >> 16) ^ ret);
 328 }
 329
 330 unsigned long OPENSSL_LH_num_items(const OPENSSL_LHASH *lh)
 331 {
 332     return lh ? lh->num_items : 0;
 333 }
 334
 335 unsigned long OPENSSL_LH_get_down_load(const OPENSSL_LHASH *lh)
 336 {
 337     return lh->down_load;
 338 }
 339
 340 void OPENSSL_LH_set_down_load(OPENSSL_LHASH *lh, unsigned long down_load)
 341 {
 342     lh->down_load = down_load;
 343 }
 344
 345 int OPENSSL_LH_error(OPENSSL_LHASH *lh)
 346 {
 347     return lh->error;
 348 }