lhash.c revision 306195 
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/*-
60 * Code for dynamic hash table routines
61 * Author - Eric Young v 2.0
62 *
63 * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
64 *           present. eay 18-Jun-98
65 *
66 * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
67 *
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
73 *
74 * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
75 *           were not being free()ed. 21/11/95
76 *
77 * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
78 *           19/09/95
79 *
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
83 *
84 * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
85 *
86 * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
87 *
88 * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
89 *
90 * 1.3 eay - Fixed a few lint problems 19/3/1991
91 *
92 * 1.2 eay - Fixed lh_doall problem 13/3/1991
93 *
94 * 1.1 eay - Added lh_doall
95 *
96 * 1.0 eay - First version
97 */
98#include <stdio.h>
99#include <string.h>
100#include <stdlib.h>
101#include <openssl/crypto.h>
102#include <openssl/lhash.h>
103
104const char lh_version[] = "lhash" OPENSSL_VERSION_PTEXT;
105
106#undef MIN_NODES
107#define MIN_NODES       16
108#define UP_LOAD         (2*LH_LOAD_MULT) /* load times 256 (default 2) */
109#define DOWN_LOAD       (LH_LOAD_MULT) /* load times 256 (default 1) */
110
111static void expand(_LHASH *lh);
112static void contract(_LHASH *lh);
113static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash);
114
115_LHASH *lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
116{
117    _LHASH *ret;
118    int i;
119
120    if ((ret = OPENSSL_malloc(sizeof(_LHASH))) == NULL)
121        goto err0;
122    if ((ret->b = OPENSSL_malloc(sizeof(LHASH_NODE *) * MIN_NODES)) == NULL)
123        goto err1;
124    for (i = 0; i < MIN_NODES; i++)
125        ret->b[i] = NULL;
126    ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
127    ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
128    ret->num_nodes = MIN_NODES / 2;
129    ret->num_alloc_nodes = MIN_NODES;
130    ret->p = 0;
131    ret->pmax = MIN_NODES / 2;
132    ret->up_load = UP_LOAD;
133    ret->down_load = DOWN_LOAD;
134    ret->num_items = 0;
135
136    ret->num_expands = 0;
137    ret->num_expand_reallocs = 0;
138    ret->num_contracts = 0;
139    ret->num_contract_reallocs = 0;
140    ret->num_hash_calls = 0;
141    ret->num_comp_calls = 0;
142    ret->num_insert = 0;
143    ret->num_replace = 0;
144    ret->num_delete = 0;
145    ret->num_no_delete = 0;
146    ret->num_retrieve = 0;
147    ret->num_retrieve_miss = 0;
148    ret->num_hash_comps = 0;
149
150    ret->error = 0;
151    return (ret);
152 err1:
153    OPENSSL_free(ret);
154 err0:
155    return (NULL);
156}
157
158void lh_free(_LHASH *lh)
159{
160    unsigned int i;
161    LHASH_NODE *n, *nn;
162
163    if (lh == NULL)
164        return;
165
166    for (i = 0; i < lh->num_nodes; i++) {
167        n = lh->b[i];
168        while (n != NULL) {
169            nn = n->next;
170            OPENSSL_free(n);
171            n = nn;
172        }
173    }
174    OPENSSL_free(lh->b);
175    OPENSSL_free(lh);
176}
177
178void *lh_insert(_LHASH *lh, void *data)
179{
180    unsigned long hash;
181    LHASH_NODE *nn, **rn;
182    void *ret;
183
184    lh->error = 0;
185    if (lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes))
186        expand(lh);
187
188    rn = getrn(lh, data, &hash);
189
190    if (*rn == NULL) {
191        if ((nn = (LHASH_NODE *)OPENSSL_malloc(sizeof(LHASH_NODE))) == NULL) {
192            lh->error++;
193            return (NULL);
194        }
195        nn->data = data;
196        nn->next = NULL;
197#ifndef OPENSSL_NO_HASH_COMP
198        nn->hash = hash;
199#endif
200        *rn = nn;
201        ret = NULL;
202        lh->num_insert++;
203        lh->num_items++;
204    } else {                    /* replace same key */
205
206        ret = (*rn)->data;
207        (*rn)->data = data;
208        lh->num_replace++;
209    }
210    return (ret);
211}
212
213void *lh_delete(_LHASH *lh, const void *data)
214{
215    unsigned long hash;
216    LHASH_NODE *nn, **rn;
217    void *ret;
218
219    lh->error = 0;
220    rn = getrn(lh, data, &hash);
221
222    if (*rn == NULL) {
223        lh->num_no_delete++;
224        return (NULL);
225    } else {
226        nn = *rn;
227        *rn = nn->next;
228        ret = nn->data;
229        OPENSSL_free(nn);
230        lh->num_delete++;
231    }
232
233    lh->num_items--;
234    if ((lh->num_nodes > MIN_NODES) &&
235        (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
236        contract(lh);
237
238    return (ret);
239}
240
241void *lh_retrieve(_LHASH *lh, const void *data)
242{
243    unsigned long hash;
244    LHASH_NODE **rn;
245    void *ret;
246
247    lh->error = 0;
248    rn = getrn(lh, data, &hash);
249
250    if (*rn == NULL) {
251        lh->num_retrieve_miss++;
252        return (NULL);
253    } else {
254        ret = (*rn)->data;
255        lh->num_retrieve++;
256    }
257    return (ret);
258}
259
260static void doall_util_fn(_LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
261                          LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
262{
263    int i;
264    LHASH_NODE *a, *n;
265
266    if (lh == NULL)
267        return;
268
269    /*
270     * reverse the order so we search from 'top to bottom' We were having
271     * memory leaks otherwise
272     */
273    for (i = lh->num_nodes - 1; i >= 0; i--) {
274        a = lh->b[i];
275        while (a != NULL) {
276            /*
277             * 28/05/91 - eay - n added so items can be deleted via lh_doall
278             */
279            /*
280             * 22/05/08 - ben - eh? since a is not passed, this should not be
281             * needed
282             */
283            n = a->next;
284            if (use_arg)
285                func_arg(a->data, arg);
286            else
287                func(a->data);
288            a = n;
289        }
290    }
291}
292
293void lh_doall(_LHASH *lh, LHASH_DOALL_FN_TYPE func)
294{
295    doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
296}
297
298void lh_doall_arg(_LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
299{
300    doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
301}
302
303static void expand(_LHASH *lh)
304{
305    LHASH_NODE **n, **n1, **n2, *np;
306    unsigned int p, i, j;
307    unsigned long hash, nni;
308
309    lh->num_nodes++;
310    lh->num_expands++;
311    p = (int)lh->p++;
312    n1 = &(lh->b[p]);
313    n2 = &(lh->b[p + (int)lh->pmax]);
314    *n2 = NULL;                 /* 27/07/92 - eay - undefined pointer bug */
315    nni = lh->num_alloc_nodes;
316
317    for (np = *n1; np != NULL;) {
318#ifndef OPENSSL_NO_HASH_COMP
319        hash = np->hash;
320#else
321        hash = lh->hash(np->data);
322        lh->num_hash_calls++;
323#endif
324        if ((hash % nni) != p) { /* move it */
325            *n1 = (*n1)->next;
326            np->next = *n2;
327            *n2 = np;
328        } else
329            n1 = &((*n1)->next);
330        np = *n1;
331    }
332
333    if ((lh->p) >= lh->pmax) {
334        j = (int)lh->num_alloc_nodes * 2;
335        n = (LHASH_NODE **)OPENSSL_realloc(lh->b,
336                                           (int)(sizeof(LHASH_NODE *) * j));
337        if (n == NULL) {
338            lh->error++;
339            lh->num_nodes--;
340            lh->p = 0;
341            return;
342        }
343        /* else */
344        for (i = (int)lh->num_alloc_nodes; i < j; i++) /* 26/02/92 eay */
345            n[i] = NULL;        /* 02/03/92 eay */
346        lh->pmax = lh->num_alloc_nodes;
347        lh->num_alloc_nodes = j;
348        lh->num_expand_reallocs++;
349        lh->p = 0;
350        lh->b = n;
351    }
352}
353
354static void contract(_LHASH *lh)
355{
356    LHASH_NODE **n, *n1, *np;
357
358    np = lh->b[lh->p + lh->pmax - 1];
359    lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
360    if (lh->p == 0) {
361        n = (LHASH_NODE **)OPENSSL_realloc(lh->b,
362                                           (unsigned int)(sizeof(LHASH_NODE *)
363                                                          * lh->pmax));
364        if (n == NULL) {
365/*                      fputs("realloc error in lhash",stderr); */
366            lh->error++;
367            return;
368        }
369        lh->num_contract_reallocs++;
370        lh->num_alloc_nodes /= 2;
371        lh->pmax /= 2;
372        lh->p = lh->pmax - 1;
373        lh->b = n;
374    } else
375        lh->p--;
376
377    lh->num_nodes--;
378    lh->num_contracts++;
379
380    n1 = lh->b[(int)lh->p];
381    if (n1 == NULL)
382        lh->b[(int)lh->p] = np;
383    else {
384        while (n1->next != NULL)
385            n1 = n1->next;
386        n1->next = np;
387    }
388}
389
390static LHASH_NODE **getrn(_LHASH *lh, const void *data, unsigned long *rhash)
391{
392    LHASH_NODE **ret, *n1;
393    unsigned long hash, nn;
394    LHASH_COMP_FN_TYPE cf;
395
396    hash = (*(lh->hash)) (data);
397    lh->num_hash_calls++;
398    *rhash = hash;
399
400    nn = hash % lh->pmax;
401    if (nn < lh->p)
402        nn = hash % lh->num_alloc_nodes;
403
404    cf = lh->comp;
405    ret = &(lh->b[(int)nn]);
406    for (n1 = *ret; n1 != NULL; n1 = n1->next) {
407#ifndef OPENSSL_NO_HASH_COMP
408        lh->num_hash_comps++;
409        if (n1->hash != hash) {
410            ret = &(n1->next);
411            continue;
412        }
413#endif
414        lh->num_comp_calls++;
415        if (cf(n1->data, data) == 0)
416            break;
417        ret = &(n1->next);
418    }
419    return (ret);
420}
421
422/*
423 * The following hash seems to work very well on normal text strings no
424 * collisions on /usr/dict/words and it distributes on %2^n quite well, not
425 * as good as MD5, but still good.
426 */
427unsigned long lh_strhash(const char *c)
428{
429    unsigned long ret = 0;
430    long n;
431    unsigned long v;
432    int r;
433
434    if ((c == NULL) || (*c == '\0'))
435        return (ret);
436/*-
437    unsigned char b[16];
438    MD5(c,strlen(c),b);
439    return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
440*/
441
442    n = 0x100;
443    while (*c) {
444        v = n | (*c);
445        n += 0x100;
446        r = (int)((v >> 2) ^ v) & 0x0f;
447        ret = (ret << r) | (ret >> (32 - r));
448        ret &= 0xFFFFFFFFL;
449        ret ^= v * v;
450        c++;
451    }
452    return ((ret >> 16) ^ ret);
453}
454
455unsigned long lh_num_items(const _LHASH *lh)
456{
457    return lh ? lh->num_items : 0;
458}
459