ossl-lhash.c   [plain text]


/*
 * Copyright (c) 2011-12 Apple Inc. All Rights Reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
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 *
 * @APPLE_LICENSE_HEADER_END@
 */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/* Code for dynamic hash table routines
 * Author - Eric Young v 2.0
 *
 * 2.2 eay - added #include "crypto.h" so the memory leak checking code is
 *	     present. eay 18-Jun-98
 *
 * 2.1 eay - Added an 'error in last operation' flag. eay 6-May-98
 *
 * 2.0 eay - Fixed a bug that occurred when using lh_delete
 *	     from inside lh_doall().  As entries were deleted,
 *	     the 'table' was 'contract()ed', making some entries
 *	     jump from the end of the table to the start, there by
 *	     skipping the lh_doall() processing. eay - 4/12/95
 *
 * 1.9 eay - Fixed a memory leak in lh_free, the LHASH_NODEs
 *	     were not being free()ed. 21/11/95
 *
 * 1.8 eay - Put the stats routines into a separate file, lh_stats.c
 *	     19/09/95
 *
 * 1.7 eay - Removed the fputs() for realloc failures - the code
 *           should silently tolerate them.  I have also fixed things
 *           lint complained about 04/05/95
 *
 * 1.6 eay - Fixed an invalid pointers in contract/expand 27/07/92
 *
 * 1.5 eay - Fixed a misuse of realloc in expand 02/03/1992
 *
 * 1.4 eay - Fixed lh_doall so the function can call lh_delete 28/05/91
 *
 * 1.3 eay - Fixed a few lint problems 19/3/1991
 *
 * 1.2 eay - Fixed lh_doall problem 13/3/1991
 *
 * 1.1 eay - Added lh_doall
 *
 * 1.0 eay - First version
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "ossl-lhash.h"

const char lh_version[] = "lhash" /* OPENSSL_VERSION_PTEXT */;

#undef MIN_NODES
#define MIN_NODES	16
#define UP_LOAD		(2*LH_LOAD_MULT)        /* load times 256  (default 2) */
#define DOWN_LOAD	(LH_LOAD_MULT)          /* load times 256  (default 1) */

static void expand(LHASH *lh);
static void contract(LHASH *lh);
static LHASH_NODE **getrn(LHASH *lh, const void *data, unsigned long *rhash);

LHASH *
lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)
{
	LHASH *ret;
	int i;

	if ((ret = (LHASH *)malloc(sizeof(LHASH))) == NULL) {
		goto err0;
	}
	if ((ret->b = (LHASH_NODE **)malloc(sizeof(LHASH_NODE *)*MIN_NODES)) == NULL) {
		goto err1;
	}
	for (i = 0; i < MIN_NODES; i++) {
		ret->b[i] = NULL;
	}
	ret->comp = ((c == NULL) ? (LHASH_COMP_FN_TYPE)strcmp : c);
	ret->hash = ((h == NULL) ? (LHASH_HASH_FN_TYPE)lh_strhash : h);
	ret->num_nodes = MIN_NODES/2;
	ret->num_alloc_nodes = MIN_NODES;
	ret->p = 0;
	ret->pmax = MIN_NODES/2;
	ret->up_load = UP_LOAD;
	ret->down_load = DOWN_LOAD;
	ret->num_items = 0;

	ret->num_expands = 0;
	ret->num_expand_reallocs = 0;
	ret->num_contracts = 0;
	ret->num_contract_reallocs = 0;
	ret->num_hash_calls = 0;
	ret->num_comp_calls = 0;
	ret->num_insert = 0;
	ret->num_replace = 0;
	ret->num_delete = 0;
	ret->num_no_delete = 0;
	ret->num_retrieve = 0;
	ret->num_retrieve_miss = 0;
	ret->num_hash_comps = 0;

	ret->error = 0;
	return (ret);

err1:
	free(ret);
err0:
	return (NULL);
}


void
lh_free(LHASH *lh)
{
	unsigned int i;
	LHASH_NODE *n, *nn;

	if (lh == NULL) {
		return;
	}

	for (i = 0; i < lh->num_nodes; i++) {
		n = lh->b[i];
		while (n != NULL) {
			nn = n->next;
			free(n);
			n = nn;
		}
	}
	free(lh->b);
	free(lh);
}


void *
lh_insert(LHASH *lh, void *data)
{
	unsigned long hash;
	LHASH_NODE *nn, **rn;
	void *ret;

	lh->error = 0;
	if (lh->up_load <= (lh->num_items*LH_LOAD_MULT/lh->num_nodes)) {
		expand(lh);
	}

	rn = getrn(lh, data, &hash);

	if (*rn == NULL) {
		if ((nn = (LHASH_NODE *)malloc(sizeof(LHASH_NODE))) == NULL) {
			lh->error++;
			return (NULL);
		}
		nn->data = data;
		nn->next = NULL;
#ifndef NO_HASH_COMP
		nn->hash = hash;
#endif
		*rn = nn;
		ret = NULL;
		lh->num_insert++;
		lh->num_items++;
	} else {
		/* replace same key */
		ret = (*rn)->data;
		(*rn)->data = data;
		lh->num_replace++;
	}
	return (ret);
}


void *
lh_delete(LHASH *lh, const void *data)
{
	unsigned long hash;
	LHASH_NODE *nn, **rn;
	void *ret;

	lh->error = 0;
	rn = getrn(lh, data, &hash);

	if (*rn == NULL) {
		lh->num_no_delete++;
		return (NULL);
	} else {
		nn = *rn;
		*rn = nn->next;
		ret = nn->data;
		free(nn);
		lh->num_delete++;
	}

	lh->num_items--;
	if ((lh->num_nodes > MIN_NODES) &&
	    (lh->down_load >= (lh->num_items*LH_LOAD_MULT/lh->num_nodes))) {
		contract(lh);
	}

	return (ret);
}


void *
lh_retrieve(LHASH *lh, const void *data)
{
	unsigned long hash;
	LHASH_NODE **rn;
	void *ret;

	lh->error = 0;
	rn = getrn(lh, data, &hash);

	if (*rn == NULL) {
		lh->num_retrieve_miss++;
		return (NULL);
	} else {
		ret = (*rn)->data;
		lh->num_retrieve++;
	}
	return (ret);
}


static void
doall_util_fn(LHASH *lh, int use_arg, LHASH_DOALL_FN_TYPE func,
    LHASH_DOALL_ARG_FN_TYPE func_arg, void *arg)
{
	int i;
	LHASH_NODE *a, *n;

	/* reverse the order so we search from 'top to bottom'
	 * We were having memory leaks otherwise */
	for (i = lh->num_nodes-1; i >= 0; i--) {
		a = lh->b[i];
		while (a != NULL) {
			/* 28/05/91 - eay - n added so items can be deleted
			 * via lh_doall */
			n = a->next;
			if (use_arg) {
				func_arg(a->data, arg);
			} else{
				func(a->data);
			}
			a = n;
		}
	}
}


void
lh_doall(LHASH *lh, LHASH_DOALL_FN_TYPE func)
{
	doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);
}


void
lh_doall_arg(LHASH *lh, LHASH_DOALL_ARG_FN_TYPE func, void *arg)
{
	doall_util_fn(lh, 1, (LHASH_DOALL_FN_TYPE)0, func, arg);
}


static void
expand(LHASH *lh)
{
	LHASH_NODE **n, **n1, **n2, *np;
	unsigned int p, i, j, pmax;
	unsigned long hash, nni;

	p = (int)lh->p++;
	nni = lh->num_alloc_nodes;
	pmax = lh->pmax;

	if ((lh->p) >= lh->pmax) {
		j = (int)lh->num_alloc_nodes*2;
		n = (LHASH_NODE **)realloc(lh->b,
			(int)sizeof(LHASH_NODE *)*j);
		if (n == NULL) {
			/* fputs("realloc error in lhash",stderr); */
			lh->error++;
			lh->p = 0;
			return;
		}
		/* else */
		for (i = (int)lh->num_alloc_nodes; i < j; i++) {
			n[i] = NULL;                        /* 02/03/92 eay */
		}
		lh->pmax = lh->num_alloc_nodes;
		lh->num_alloc_nodes = j;
		lh->num_expand_reallocs++;
		lh->p = 0;
		lh->b = n;
	}

	lh->num_nodes++;
	lh->num_expands++;
	n1 = &(lh->b[p]);
	n2 = &(lh->b[p+pmax]);
	*n2 = NULL;        /* 27/07/92 - eay - undefined pointer bug */

	for (np = *n1; np != NULL; ) {
#ifndef NO_HASH_COMP
		hash = np->hash;
#else
		hash = lh->hash(np->data);
		lh->num_hash_calls++;
#endif
		if ((hash%nni) != p) {
			/* move it */
			*n1 = (*n1)->next;
			np->next = *n2;
			*n2 = np;
		} else{
			n1 = &((*n1)->next);
		}
		np = *n1;
	}
}


static void
contract(LHASH *lh)
{
	LHASH_NODE **n, *n1, *np;
	int idx = lh->p+lh->pmax-1;

	np = lh->b[idx];
	if (lh->p == 0) {
		n = (LHASH_NODE **)realloc(lh->b,
			(unsigned int)(sizeof(LHASH_NODE *)*lh->pmax));
		if (n == NULL) {
			/* fputs("realloc error in lhash",stderr); */
			lh->error++;
			return;
		}
		lh->num_contract_reallocs++;
		lh->num_alloc_nodes /= 2;
		lh->pmax /= 2;
		lh->p = lh->pmax-1;
		lh->b = n;
	}else  {
		lh->p--;
	}

	lh->b[idx] = NULL;
	lh->num_nodes--;
	lh->num_contracts++;

	n1 = lh->b[(int)lh->p];
	if (n1 == NULL) {
		lh->b[(int)lh->p] = np;
	} else{
		while (n1->next != NULL) {
			n1 = n1->next;
		}
		n1->next = np;
	}
}


static LHASH_NODE **
getrn(LHASH *lh, const void *data, unsigned long *rhash)
{
	LHASH_NODE **ret, *n1;
	unsigned long hash, nn;
	LHASH_COMP_FN_TYPE cf;

	hash = (*(lh->hash))(data);
	lh->num_hash_calls++;
	*rhash = hash;

	nn = hash%lh->pmax;
	if (nn < lh->p) {
		nn = hash%lh->num_alloc_nodes;
	}

	cf = lh->comp;
	ret = &(lh->b[(int)nn]);
	for (n1 = *ret; n1 != NULL; n1 = n1->next) {
#ifndef NO_HASH_COMP
		lh->num_hash_comps++;
		if (n1->hash != hash) {
			ret = &(n1->next);
			continue;
		}
#endif
		lh->num_comp_calls++;
		if (cf(n1->data, data) == 0) {
			break;
		}
		ret = &(n1->next);
	}
	return (ret);
}


/* The following hash seems to work very well on normal text strings
 * no collisions on /usr/dict/words and it distributes on %2^n quite
 * well, not as good as MD5, but still good.
 */
unsigned long
lh_strhash(const char *c)
{
	unsigned long ret = 0;
	long n;
	unsigned long v;
	int r;

	if ((c == NULL) || (*c == '\0')) {
		return (ret);
	}

/*
 *      unsigned char b[16];
 *      MD5(c,strlen(c),b);
 *      return(b[0]|(b[1]<<8)|(b[2]<<16)|(b[3]<<24));
 */

	n = 0x100;
	while (*c) {
		v = n|(*c);
		n += 0x100;
		r = (int)((v>>2)^v)&0x0f;
		ret = (ret<<r)|(ret>>(32-r));
		ret &= 0xFFFFFFFFL;
		ret ^= v*v;
		c++;
	}
	return ((ret>>16)^ret);
}


unsigned long
lh_num_items(const LHASH *lh)
{
	return (lh ? lh->num_items : 0);
}