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lhash.c
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1 /* crypto/lhash/lhash.c */
2 /* Copyright (C) 1995-1998 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 /* Code for dynamic hash table routines
60  * Author - Eric Young v 2.0
61  *
62  * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
63  * present. eay 18-Jun-98
64  *
65  * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
66  *
67  * 2.0 eay - Fixed a bug that occurred when using lh_delete
68  * from inside lh_doall(). As entries were deleted,
69  * the 'table' was 'contract()ed', making some entries
70  * jump from the end of the table to the start, there by
71  * skipping the lh_doall() processing. eay - 4/12/95
72  *
73  * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
74  * were not being free()ed. 21/11/95
75  *
76  * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
77  * 19/09/95
78  *
79  * 1.7 eay - Removed the fputs() for realloc failures - the code
80  * should silently tolerate them. I have also fixed things
81  * lint complained about 04/05/95
82  *
83  * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
84  *
85  * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
86  *
87  * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
88  *
89  * 1.3 eay - Fixed a few lint problems 19/3/1991
90  *
91  * 1.2 eay - Fixed lh_doall problem 13/3/1991
92  *
93  * 1.1 eay - Added lh_doall
94  *
95  * 1.0 eay - First version
96  */
97 #include <stdio.h>
98 #include <string.h>
99 #include <stdlib.h>
100 #include <openssl/crypto.h>
101 #include <openssl/lhash.h>
102 
103 const char lh_version[]="lhash" OPENSSL_VERSION_PTEXT;
104 
105 #undef MIN_NODES
106 #define MIN_NODES 16
107 #define UP_LOAD (2*LH_LOAD_MULT) /* load times 256 (default 2) */
108 #define DOWN_LOAD (LH_LOAD_MULT) /* load times 256 (default 1) */
109 
110 static void expand(_LHASH *lh);
111 static void contract(_LHASH *lh);
112 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash);
113 
115  {
116  _LHASH *ret;
117  int i;
118 
119  if ((ret=OPENSSL_malloc(sizeof(_LHASH))) == NULL)
120  goto err0;
121  if ((ret->b=OPENSSL_malloc(sizeof(LHASH_NODE *)*MIN_NODES)) == NULL)
122  goto err1;
123  for (i=0; i<MIN_NODES; i++)
124  ret->b[i]=NULL;
125  ret->comp=((c == NULL)?(LHASH_COMP_FN_TYPE)strcmp:c);
126  ret->hash=((h == NULL)?(LHASH_HASH_FN_TYPE)lh_strhash:h);
127  ret->num_nodes=MIN_NODES/2;
129  ret->p=0;
130  ret->pmax=MIN_NODES/2;
131  ret->up_load=UP_LOAD;
132  ret->down_load=DOWN_LOAD;
133  ret->num_items=0;
134 
135  ret->num_expands=0;
136  ret->num_expand_reallocs=0;
137  ret->num_contracts=0;
138  ret->num_contract_reallocs=0;
139  ret->num_hash_calls=0;
140  ret->num_comp_calls=0;
141  ret->num_insert=0;
142  ret->num_replace=0;
143  ret->num_delete=0;
144  ret->num_no_delete=0;
145  ret->num_retrieve=0;
146  ret->num_retrieve_miss=0;
147  ret->num_hash_comps=0;
148 
149  ret->error=0;
150  return(ret);
151 err1:
152  OPENSSL_free(ret);
153 err0:
154  return(NULL);
155  }
156 
157 void lh_free(_LHASH *lh)
158  {
159  unsigned int i;
160  LHASH_NODE *n,*nn;
161 
162  if (lh == NULL)
163  return;
164 
165  for (i=0; i<lh->num_nodes; i++)
166  {
167  n=lh->b[i];
168  while (n != NULL)
169  {
170  nn=n->next;
171  OPENSSL_free(n);
172  n=nn;
173  }
174  }
175  OPENSSL_free(lh->b);
176  OPENSSL_free(lh);
177  }
178 
179 void *lh_insert(_LHASH *lh, void *data)
180  {
181  unsigned long hash;
182  LHASH_NODE *nn,**rn;
183  void *ret;
184 
185  lh->error=0;
186  if (lh->up_load <= (lh->num_items*LH_LOAD_MULT/lh->num_nodes))
187  expand(lh);
188 
189  rn=getrn(lh,data,&hash);
190 
191  if (*rn == NULL)
192  {
193  if ((nn=(LHASH_NODE *)OPENSSL_malloc(sizeof(LHASH_NODE))) == NULL)
194  {
195  lh->error++;
196  return(NULL);
197  }
198  nn->data=data;
199  nn->next=NULL;
200 #ifndef OPENSSL_NO_HASH_COMP
201  nn->hash=hash;
202 #endif
203  *rn=nn;
204  ret=NULL;
205  lh->num_insert++;
206  lh->num_items++;
207  }
208  else /* replace same key */
209  {
210  ret= (*rn)->data;
211  (*rn)->data=data;
212  lh->num_replace++;
213  }
214  return(ret);
215  }
216 
217 void *lh_delete(_LHASH *lh, const void *data)
218  {
219  unsigned long hash;
220  LHASH_NODE *nn,**rn;
221  void *ret;
222 
223  lh->error=0;
224  rn=getrn(lh,data,&hash);
225 
226  if (*rn == NULL)
227  {
228  lh->num_no_delete++;
229  return(NULL);
230  }
231  else
232  {
233  nn= *rn;
234  *rn=nn->next;
235  ret=nn->data;
236  OPENSSL_free(nn);
237  lh->num_delete++;
238  }
239 
240  lh->num_items--;
241  if ((lh->num_nodes > MIN_NODES) &&
242  (lh->down_load >= (lh->num_items*LH_LOAD_MULT/lh->num_nodes)))
243  contract(lh);
244 
245  return(ret);
246  }
247 
248 void *lh_retrieve(_LHASH *lh, const void *data)
249  {
250  unsigned long hash;
251  LHASH_NODE **rn;
252  void *ret;
253 
254  lh->error=0;
255  rn=getrn(lh,data,&hash);
256 
257  if (*rn == NULL)
258  {
259  lh->num_retrieve_miss++;
260  return(NULL);
261  }
262  else
263  {
264  ret= (*rn)->data;
265  lh->num_retrieve++;
266  }
267  return(ret);
268  }
269 
270 static void doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
271  LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
272  {
273  int i;
274  LHASH_NODE *a,*n;
275 
276  if (lh == NULL)
277  return;
278 
279  /* reverse the order so we search from 'top to bottom'
280  * We were having memory leaks otherwise */
281  for (i=lh->num_nodes-1; i>=0; i--)
282  {
283  a=lh->b[i];
284  while (a != NULL)
285  {
286  /* 28/05/91 - eay - n added so items can be deleted
287  * via lh_doall */
288  /* 22/05/08 - ben - eh? since a is not passed,
289  * this should not be needed */
290  n=a->next;
291  if(use_arg)
292  func_arg(a->data,arg);
293  else
294  func(a->data);
295  a=n;
296  }
297  }
298  }
299 
301  {
302  doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
303  }
304 
305 void lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
306  {
307  doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
308  }
309 
310 static void expand(_LHASH *lh)
311  {
312  LHASH_NODE **n,**n1,**n2,*np;
313  unsigned int p,i,j;
314  unsigned long hash,nni;
315 
316  lh->num_nodes++;
317  lh->num_expands++;
318  p=(int)lh->p++;
319  n1= &(lh->b[p]);
320  n2= &(lh->b[p+(int)lh->pmax]);
321  *n2=NULL; /* 27/07/92 - eay - undefined pointer bug */
322  nni=lh->num_alloc_nodes;
323 
324  for (np= *n1; np != NULL; )
325  {
326 #ifndef OPENSSL_NO_HASH_COMP
327  hash=np->hash;
328 #else
329  hash=lh->hash(np->data);
330  lh->num_hash_calls++;
331 #endif
332  if ((hash%nni) != p)
333  { /* move it */
334  *n1= (*n1)->next;
335  np->next= *n2;
336  *n2=np;
337  }
338  else
339  n1= &((*n1)->next);
340  np= *n1;
341  }
342 
343  if ((lh->p) >= lh->pmax)
344  {
345  j=(int)lh->num_alloc_nodes*2;
346  n=(LHASH_NODE **)OPENSSL_realloc(lh->b,
347  (int)(sizeof(LHASH_NODE *)*j));
348  if (n == NULL)
349  {
350 /* fputs("realloc error in lhash",stderr); */
351  lh->error++;
352  lh->p=0;
353  return;
354  }
355  /* else */
356  for (i=(int)lh->num_alloc_nodes; i<j; i++)/* 26/02/92 eay */
357  n[i]=NULL; /* 02/03/92 eay */
358  lh->pmax=lh->num_alloc_nodes;
359  lh->num_alloc_nodes=j;
360  lh->num_expand_reallocs++;
361  lh->p=0;
362  lh->b=n;
363  }
364  }
365 
366 static void contract(_LHASH *lh)
367  {
368  LHASH_NODE **n,*n1,*np;
369 
370  np=lh->b[lh->p+lh->pmax-1];
371  lh->b[lh->p+lh->pmax-1]=NULL; /* 24/07-92 - eay - weird but :-( */
372  if (lh->p == 0)
373  {
374  n=(LHASH_NODE **)OPENSSL_realloc(lh->b,
375  (unsigned int)(sizeof(LHASH_NODE *)*lh->pmax));
376  if (n == NULL)
377  {
378 /* fputs("realloc error in lhash",stderr); */
379  lh->error++;
380  return;
381  }
382  lh->num_contract_reallocs++;
383  lh->num_alloc_nodes/=2;
384  lh->pmax/=2;
385  lh->p=lh->pmax-1;
386  lh->b=n;
387  }
388  else
389  lh->p--;
390 
391  lh->num_nodes--;
392  lh->num_contracts++;
393 
394  n1=lh->b[(int)lh->p];
395  if (n1 == NULL)
396  lh->b[(int)lh->p]=np;
397  else
398  {
399  while (n1->next != NULL)
400  n1=n1->next;
401  n1->next=np;
402  }
403  }
404 
405 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash)
406  {
407  LHASH_NODE **ret,*n1;
408  unsigned long hash,nn;
410 
411  hash=(*(lh->hash))(data);
412  lh->num_hash_calls++;
413  *rhash=hash;
414 
415  nn=hash%lh->pmax;
416  if (nn < lh->p)
417  nn=hash%lh->num_alloc_nodes;
418 
419  cf=lh->comp;
420  ret= &(lh->b[(int)nn]);
421  for (n1= *ret; n1 != NULL; n1=n1->next)
422  {
423 #ifndef OPENSSL_NO_HASH_COMP
424  lh->num_hash_comps++;
425  if (n1->hash != hash)
426  {
427  ret= &(n1->next);
428  continue;
429  }
430 #endif
431  lh->num_comp_calls++;
432  if(cf(n1->data,data) == 0)
433  break;
434  ret= &(n1->next);
435  }
436  return(ret);
437  }
438 
439 /* The following hash seems to work very well on normal text strings
440  * no collisions on /usr/dict/words and it distributes on %2^n quite
441  * well, not as good as MD5, but still good.
442  */
443 unsigned long lh_strhash(const char *c)
444  {
445  unsigned long ret=0;
446  long n;
447  unsigned long v;
448  int r;
449 
450  if ((c == NULL) || (*c == '\0'))
451  return(ret);
452 /*
453  unsigned char b[16];
454  MD5(c,strlen(c),b);
455  return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
456 */
457 
458  n=0x100;
459  while (*c)
460  {
461  v=n|(*c);
462  n+=0x100;
463  r= (int)((v>>2)^v)&0x0f;
464  ret=(ret<<r)|(ret>>(32-r));
465  ret&=0xFFFFFFFFL;
466  ret^=v*v;
467  c++;
468  }
469  return((ret>>16)^ret);
470  }
471 
472 unsigned long lh_num_items(const _LHASH *lh)
473  {
474  return lh ? lh->num_items : 0;
475  }