crypto/lhash/lhash.c

   1 /* crypto/lhash/lhash.c */
   2 /* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 char *lh_version="lhash part of SSLeay 0.8.1b 29-Jun-1998";
  60
  61 /* Code for dynamic hash table routines
  62  * Author - Eric Young v 2.0
  63  *
  64  * 2.0 eay - Fixed a bug that occured when using lh_delete
  65  *           from inside lh_doall().  As entries were deleted,
  66  *           the 'table' was 'contract()ed', making some entries
  67  *           jump from the end of the table to the start, there by
  68  *           skiping the lh_doall() processing. eay - 4/12/95
  69  *
  70  * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
  71  *           were not being free()ed. 21/11/95
  72  *
  73  * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
  74  *           19/09/95
  75  *
  76  * 1.7 eay - Removed the fputs() for realloc failures - the code
  77  *           should silently tolerate them.  I have also fixed things
  78  *           lint complained about 04/05/95
  79  *
  80  * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
  81  *
  82  * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
  83  *
  84  * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
  85  *
  86  * 1.3 eay - Fixed a few lint problems 19/3/1991
  87  *
  88  * 1.2 eay - Fixed lh_doall problem 13/3/1991
  89  *
  90  * 1.1 eay - Added lh_doall
  91  *
  92  * 1.0 eay - First version
  93  */
  94 #include <stdio.h>
  95 #include <string.h>
  96 #include <stdlib.h>
  97 #include "lhash.h"
  98
  99 #undef MIN_NODES
 100 #define MIN_NODES       16
 101 #define UP_LOAD         (2*LH_LOAD_MULT) /* load times 256  (default 2) */
 102 #define DOWN_LOAD       (LH_LOAD_MULT)   /* load times 256  (default 1) */
 103
 104 #ifndef NOPROTO
 105
 106 #define P_CP    char *
 107 #define P_CPP   char *,char *
 108 static void expand(LHASH *lh);
 109 static void contract(LHASH *lh);
 110 static LHASH_NODE **getrn(LHASH *lh, char *data, unsigned long *rhash);
 111
 112 #else
 113
 114 #define P_CP
 115 #define P_CPP
 116 static void expand();
 117 static void contract();
 118 static LHASH_NODE **getrn();
 119
 120 #endif
 121
 122 LHASH *lh_new(h, c)
 123 unsigned long (*h)();
 124 int (*c)();
 125         {
 126         LHASH *ret;
 127         int i;
 128
 129         if ((ret=(LHASH *)malloc(sizeof(LHASH))) == NULL)
 130                 goto err0;
 131         if ((ret->b=(LHASH_NODE **)malloc(sizeof(LHASH_NODE *)*MIN_NODES)) == NULL)
 132                 goto err1;
 133         for (i=0; i<MIN_NODES; i++)
 134                 ret->b[i]=NULL;
 135         ret->comp=((c == NULL)?(int (*)())strcmp:c);
 136         ret->hash=((h == NULL)?(unsigned long (*)())lh_strhash:h);
 137         ret->num_nodes=MIN_NODES/2;
 138         ret->num_alloc_nodes=MIN_NODES;
 139         ret->p=0;
 140         ret->pmax=MIN_NODES/2;
 141         ret->up_load=UP_LOAD;
 142         ret->down_load=DOWN_LOAD;
 143         ret->num_items=0;
 144
 145         ret->num_expands=0;
 146         ret->num_expand_reallocs=0;
 147         ret->num_contracts=0;
 148         ret->num_contract_reallocs=0;
 149         ret->num_hash_calls=0;
 150         ret->num_comp_calls=0;
 151         ret->num_insert=0;
 152         ret->num_replace=0;
 153         ret->num_delete=0;
 154         ret->num_no_delete=0;
 155         ret->num_retrieve=0;
 156         ret->num_retrieve_miss=0;
 157         ret->num_hash_comps=0;
 158
 159         return(ret);
 160 err1:
 161         free((char *)ret);
 162 err0:
 163         return(NULL);
 164         }
 165
 166 void lh_free(lh)
 167 LHASH *lh;
 168         {
 169         unsigned int i;
 170         LHASH_NODE *n,*nn;
 171
 172         for (i=0; i<lh->num_nodes; i++)
 173                 {
 174                 n=lh->b[i];
 175                 while (n != NULL)
 176                         {
 177                         nn=n->next;
 178                         free(n);
 179                         n=nn;
 180                         }
 181                 }
 182         free((char *)lh->b);
 183         free((char *)lh);
 184         }
 185
 186 char *lh_insert(lh, data)
 187 LHASH *lh;
 188 char *data;
 189         {
 190         unsigned long hash;
 191         LHASH_NODE *nn,**rn;
 192         char *ret;
 193
 194         if (lh->up_load <= (lh->num_items*LH_LOAD_MULT/lh->num_nodes))
 195                 expand(lh);
 196
 197         rn=getrn(lh,data,&hash);
 198
 199         if (*rn == NULL)
 200                 {
 201                 if ((nn=(LHASH_NODE *)malloc(sizeof(LHASH_NODE))) == NULL)
 202                         return(NULL);
 203                 nn->data=data;
 204                 nn->next=NULL;
 205 #ifndef NO_HASH_COMP
 206                 nn->hash=hash;
 207 #endif
 208                 *rn=nn;
 209                 ret=NULL;
 210                 lh->num_insert++;
 211                 lh->num_items++;
 212                 }
 213         else /* replace same key */
 214                 {
 215                 ret= (*rn)->data;
 216                 (*rn)->data=data;
 217                 lh->num_replace++;
 218                 }
 219         return(ret);
 220         }
 221
 222 char *lh_delete(lh, data)
 223 LHASH *lh;
 224 char *data;
 225         {
 226         unsigned long hash;
 227         LHASH_NODE *nn,**rn;
 228         char *ret;
 229
 230         rn=getrn(lh,data,&hash);
 231
 232         if (*rn == NULL)
 233                 {
 234                 lh->num_no_delete++;
 235                 return(NULL);
 236                 }
 237         else
 238                 {
 239                 nn= *rn;
 240                 *rn=nn->next;
 241                 ret=nn->data;
 242                 free((char *)nn);
 243                 lh->num_delete++;
 244                 }
 245
 246         lh->num_items--;
 247         if ((lh->num_nodes > MIN_NODES) &&
 248                 (lh->down_load >= (lh->num_items*LH_LOAD_MULT/lh->num_nodes)))
 249                 contract(lh);
 250
 251         return(ret);
 252         }
 253
 254 char *lh_retrieve(lh, data)
 255 LHASH *lh;
 256 char *data;
 257         {
 258         unsigned long hash;
 259         LHASH_NODE **rn;
 260         char *ret;
 261
 262         rn=getrn(lh,data,&hash);
 263
 264         if (*rn == NULL)
 265                 {
 266                 lh->num_retrieve_miss++;
 267                 return(NULL);
 268                 }
 269         else
 270                 {
 271                 ret= (*rn)->data;
 272                 lh->num_retrieve++;
 273                 }
 274         return(ret);
 275         }
 276
 277 void lh_doall(lh, func)
 278 LHASH *lh;
 279 void (*func)();
 280         {
 281         lh_doall_arg(lh,func,NULL);
 282         }
 283
 284 void lh_doall_arg(lh, func, arg)
 285 LHASH *lh;
 286 void (*func)();
 287 char *arg;
 288         {
 289         int i;
 290         LHASH_NODE *a,*n;
 291
 292         /* reverse the order so we search from 'top to bottom'
 293          * We were having memory leaks otherwise */
 294         for (i=lh->num_nodes-1; i>=0; i--)
 295                 {
 296                 a=lh->b[i];
 297                 while (a != NULL)
 298                         {
 299                         /* 28/05/91 - eay - n added so items can be deleted
 300                          * via lh_doall */
 301                         n=a->next;
 302                         func(a->data,arg);
 303                         a=n;
 304                         }
 305                 }
 306         }
 307
 308 static void expand(lh)
 309 LHASH *lh;
 310         {
 311         LHASH_NODE **n,**n1,**n2,*np;
 312         unsigned int p,i,j;
 313         unsigned long hash,nni;
 314
 315         lh->num_nodes++;
 316         lh->num_expands++;
 317         p=(int)lh->p++;
 318         n1= &(lh->b[p]);
 319         n2= &(lh->b[p+(int)lh->pmax]);
 320         *n2=NULL;        /* 27/07/92 - eay - undefined pointer bug */
 321         nni=lh->num_alloc_nodes;
 322
 323         for (np= *n1; np != NULL; )
 324                 {
 325 #ifndef NO_HASH_COMP
 326                 hash=np->hash;
 327 #else
 328                 hash=(*(lh->hash))(np->data);
 329                 lh->num_hash_calls++;
 330 #endif
 331                 if ((hash%nni) != p)
 332                         { /* move it */
 333                         *n1= (*n1)->next;
 334                         np->next= *n2;
 335                         *n2=np;
 336                         }
 337                 else
 338                         n1= &((*n1)->next);
 339                 np= *n1;
 340                 }
 341
 342         if ((lh->p) >= lh->pmax)
 343                 {
 344                 j=(int)lh->num_alloc_nodes*2;
 345                 n=(LHASH_NODE **)realloc((char *)lh->b,
 346                         (unsigned int)sizeof(LHASH_NODE *)*j);
 347                 if (n == NULL)
 348                         {
 349 /*                      fputs("realloc error in lhash",stderr); */
 350                         lh->p=0;
 351                         return;
 352                         }
 353                 /* else */
 354                 for (i=(int)lh->num_alloc_nodes; i<j; i++)/* 26/02/92 eay */
 355                         n[i]=NULL;                        /* 02/03/92 eay */
 356                 lh->pmax=lh->num_alloc_nodes;
 357                 lh->num_alloc_nodes=j;
 358                 lh->num_expand_reallocs++;
 359                 lh->p=0;
 360                 lh->b=n;
 361                 }
 362         }
 363
 364 static void contract(lh)
 365 LHASH *lh;
 366         {
 367         LHASH_NODE **n,*n1,*np;
 368
 369         np=lh->b[lh->p+lh->pmax-1];
 370         lh->b[lh->p+lh->pmax-1]=NULL; /* 24/07-92 - eay - weird but :-( */
 371         if (lh->p == 0)
 372                 {
 373                 n=(LHASH_NODE **)realloc((char *)lh->b,
 374                         (unsigned int)(sizeof(LHASH_NODE *)*lh->pmax));
 375                 if (n == NULL)
 376                         {
 377 /*                      fputs("realloc error in lhash",stderr); */
 378                         return;
 379                         }
 380                 lh->num_contract_reallocs++;
 381                 lh->num_alloc_nodes/=2;
 382                 lh->pmax/=2;
 383                 lh->p=lh->pmax-1;
 384                 lh->b=n;
 385                 }
 386         else
 387                 lh->p--;
 388
 389         lh->num_nodes--;
 390         lh->num_contracts++;
 391
 392         n1=lh->b[(int)lh->p];
 393         if (n1 == NULL)
 394                 lh->b[(int)lh->p]=np;
 395         else
 396                 {
 397                 while (n1->next != NULL)
 398                         n1=n1->next;
 399                 n1->next=np;
 400                 }
 401         }
 402
 403 static LHASH_NODE **getrn(lh, data, rhash)
 404 LHASH *lh;
 405 char *data;
 406 unsigned long *rhash;
 407         {
 408         LHASH_NODE **ret,*n1;
 409         unsigned long hash,nn;
 410         int (*cf)();
 411
 412         hash=(*(lh->hash))(data);
 413         lh->num_hash_calls++;
 414         *rhash=hash;
 415
 416         nn=hash%lh->pmax;
 417         if (nn < lh->p)
 418                 nn=hash%lh->num_alloc_nodes;
 419
 420         cf=lh->comp;
 421         ret= &(lh->b[(int)nn]);
 422         for (n1= *ret; n1 != NULL; n1=n1->next)
 423                 {
 424 #ifndef NO_HASH_COMP
 425                 lh->num_hash_comps++;
 426                 if (n1->hash != hash)
 427                         {
 428                         ret= &(n1->next);
 429                         continue;
 430                         }
 431 #endif
 432                 lh->num_comp_calls++;
 433                 if ((*cf)(n1->data,data) == 0)
 434                         break;
 435                 ret= &(n1->next);
 436                 }
 437         return(ret);
 438         }
 439
 440 /*
 441 static unsigned long lh_strhash(str)
 442 char *str;
 443         {
 444         int i,l;
 445         unsigned long ret=0;
 446         unsigned short *s;
 447
 448         if (str == NULL) return(0);
 449         l=(strlen(str)+1)/2;
 450         s=(unsigned short *)str;
 451         for (i=0; i<l; i++)
 452                 ret^=(s[i]<<(i&0x0f));
 453         return(ret);
 454         } */
 455
 456 /* The following hash seems to work very well on normal text strings
 457  * no collisions on /usr/dict/words and it distributes on %2^n quite
 458  * well, not as good as MD5, but still good.
 459  */
 460 unsigned long lh_strhash(c)
 461 char *c;
 462         {
 463         unsigned long ret=0;
 464         long n;
 465         unsigned long v;
 466         int r;
 467
 468         if ((c == NULL) || (*c == '\0'))
 469                 return(ret);
 470 /*
 471         unsigned char b[16];
 472         MD5(c,strlen(c),b);
 473         return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
 474 */
 475
 476         n=0x100;
 477         while (*c)
 478                 {
 479                 v=n|(*c);
 480                 n+=0x100;
 481                 r= (int)((v>>2)^v)&0x0f;
 482                 ret=(ret<<r)|(ret>>(32-r));
 483                 ret&=0xFFFFFFFFL;
 484                 ret^=v*v;
 485                 c++;
 486                 }
 487         return((ret>>16)^ret);
 488         }
 489