1 /* crypto/lhash/lhash.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
60 * Code for dynamic hash table routines
61 * Author - Eric Young v 2.0
63 * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
64 * present. eay 18-Jun-98
66 * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
68 * 2.0 eay - Fixed a bug that occurred when using lh_delete
69 * from inside lh_doall(). As entries were deleted,
70 * the 'table' was 'contract()ed', making some entries
71 * jump from the end of the table to the start, there by
72 * skipping the lh_doall() processing. eay - 4/12/95
74 * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
75 * were not being free()ed. 21/11/95
77 * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
80 * 1.7 eay - Removed the fputs() for realloc failures - the code
81 * should silently tolerate them. I have also fixed things
82 * lint complained about 04/05/95
84 * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
86 * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
88 * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
90 * 1.3 eay - Fixed a few lint problems 19/3/1991
92 * 1.2 eay - Fixed lh_doall problem 13/3/1991
94 * 1.1 eay - Added lh_doall
96 * 1.0 eay - First version
101 #include <openssl/crypto.h>
102 #include <openssl/lhash.h>
105 * A hashing implementation that appears to be based on the linear hashing
107 * https://en.wikipedia.org/wiki/Linear_hashing
109 * Litwin, Witold (1980), "Linear hashing: A new tool for file and table
110 * addressing", Proc. 6th Conference on Very Large Databases: 212-223
111 * http://hackthology.com/pdfs/Litwin-1980-Linear_Hashing.pdf
113 * From the wikipedia article "Linear hashing is used in the BDB Berkeley
114 * database system, which in turn is used by many software systems such as
115 * OpenLDAP, using a C implementation derived from the CACM article and first
116 * published on the Usenet in 1988 by Esmond Pitt."
118 * The CACM paper is available here:
119 * https://pdfs.semanticscholar.org/ff4d/1c5deca6269cc316bfd952172284dbf610ee.pdf
122 const char lh_version[] = "lhash" OPENSSL_VERSION_PTEXT;
126 #define UP_LOAD (2*LH_LOAD_MULT) /* load times 256 (default 2) */
127 #define DOWN_LOAD (LH_LOAD_MULT) /* load times 256 (default 1) */
129 static int expand(_LHASH *lh);
130 static void contract(_LHASH *lh);
131 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash);
133 _LHASH *lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
138 if ((ret = OPENSSL_malloc(sizeof(_LHASH))) == NULL)
140 if ((ret->b = OPENSSL_malloc(sizeof(LHASH_NODE *) * MIN_NODES)) == NULL)
142 for (i = 0; i < MIN_NODES; i++)
144 ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
145 ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
146 ret->num_nodes = MIN_NODES / 2;
147 ret->num_alloc_nodes = MIN_NODES;
149 ret->pmax = MIN_NODES / 2;
150 ret->up_load = UP_LOAD;
151 ret->down_load = DOWN_LOAD;
154 ret->num_expands = 0;
155 ret->num_expand_reallocs = 0;
156 ret->num_contracts = 0;
157 ret->num_contract_reallocs = 0;
158 ret->num_hash_calls = 0;
159 ret->num_comp_calls = 0;
161 ret->num_replace = 0;
163 ret->num_no_delete = 0;
164 ret->num_retrieve = 0;
165 ret->num_retrieve_miss = 0;
166 ret->num_hash_comps = 0;
176 void lh_free(_LHASH *lh)
184 for (i = 0; i < lh->num_nodes; i++) {
196 void *lh_insert(_LHASH *lh, void *data)
199 LHASH_NODE *nn, **rn;
203 if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)
207 rn = getrn(lh, data, &hash);
210 if ((nn = (LHASH_NODE *)OPENSSL_malloc(sizeof(LHASH_NODE))) == NULL) {
216 #ifndef OPENSSL_NO_HASH_COMP
223 } else { /* replace same key */
232 void *lh_delete(_LHASH *lh, const void *data)
235 LHASH_NODE *nn, **rn;
239 rn = getrn(lh, data, &hash);
253 if ((lh->num_nodes > MIN_NODES) &&
254 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
260 void *lh_retrieve(_LHASH *lh, const void *data)
267 rn = getrn(lh, data, &hash);
270 lh->num_retrieve_miss++;
279 static void doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
280 LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
289 * reverse the order so we search from 'top to bottom' We were having
290 * memory leaks otherwise
292 for (i = lh->num_nodes - 1; i >= 0; i--) {
296 * 28/05/91 - eay - n added so items can be deleted via lh_doall
299 * 22/05/08 - ben - eh? since a is not passed, this should not be
304 func_arg(a->data, arg);
312 void lh_doall(_LHASH *lh, LHASH_DOALL_FN_TYPE func)
314 doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
317 void lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
319 doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
322 static int expand(_LHASH *lh)
324 LHASH_NODE **n, **n1, **n2, *np;
325 unsigned int p, pmax, nni, j;
328 nni = lh->num_alloc_nodes;
333 n = OPENSSL_realloc(lh->b, (int)(sizeof(LHASH_NODE *) * j));
339 memset(n + nni, 0, sizeof(*n) * (j - nni));
341 lh->num_alloc_nodes = j;
342 lh->num_expand_reallocs++;
351 n2 = &(lh->b[p + pmax]);
354 for (np = *n1; np != NULL;) {
355 #ifndef OPENSSL_NO_HASH_COMP
358 hash = lh->hash(np->data);
359 lh->num_hash_calls++;
361 if ((hash % nni) != p) { /* move it */
373 static void contract(_LHASH *lh)
375 LHASH_NODE **n, *n1, *np;
377 np = lh->b[lh->p + lh->pmax - 1];
378 lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
380 n = (LHASH_NODE **)OPENSSL_realloc(lh->b,
381 (unsigned int)(sizeof(LHASH_NODE *)
384 /* fputs("realloc error in lhash",stderr); */
388 lh->num_contract_reallocs++;
389 lh->num_alloc_nodes /= 2;
391 lh->p = lh->pmax - 1;
399 n1 = lh->b[(int)lh->p];
401 lh->b[(int)lh->p] = np;
403 while (n1->next != NULL)
409 static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash)
411 LHASH_NODE **ret, *n1;
412 unsigned long hash, nn;
413 LHASH_COMP_FN_TYPE cf;
415 hash = (*(lh->hash)) (data);
416 lh->num_hash_calls++;
419 nn = hash % lh->pmax;
421 nn = hash % lh->num_alloc_nodes;
424 ret = &(lh->b[(int)nn]);
425 for (n1 = *ret; n1 != NULL; n1 = n1->next) {
426 #ifndef OPENSSL_NO_HASH_COMP
427 lh->num_hash_comps++;
428 if (n1->hash != hash) {
433 lh->num_comp_calls++;
434 if (cf(n1->data, data) == 0)
442 * The following hash seems to work very well on normal text strings no
443 * collisions on /usr/dict/words and it distributes on %2^n quite well, not
444 * as good as MD5, but still good.
446 unsigned long lh_strhash(const char *c)
448 unsigned long ret = 0;
453 if ((c == NULL) || (*c == '\0'))
458 return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
465 r = (int)((v >> 2) ^ v) & 0x0f;
466 ret = (ret << r) | (ret >> (32 - r));
471 return ((ret >> 16) ^ ret);
474 unsigned long lh_num_items(const _LHASH *lh)
476 return lh ? lh->num_items : 0;