/* crypto/lhash/lhash.c */

/* 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 <openssl/crypto.h>

#include <openssl/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);

EXPORT_C LHASH *lh_new(LHASH_HASH_FN_TYPE h, LHASH_COMP_FN_TYPE c)

	{

	LHASH *ret;

	int i;

	if ((ret=(LHASH *)OPENSSL_malloc(sizeof(LHASH))) == NULL)

		goto err0;

	if ((ret->b=(LHASH_NODE **)OPENSSL_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:

	OPENSSL_free(ret);

err0:

	return(NULL);

	}

EXPORT_C 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;

			OPENSSL_free(n);

			n=nn;

			}

		}

	OPENSSL_free(lh->b);

	OPENSSL_free(lh);

	}

EXPORT_C 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 *)OPENSSL_malloc(sizeof(LHASH_NODE))) == NULL)

			{

			lh->error++;

			return(NULL);

			}

		nn->data=data;

		nn->next=NULL;

#ifndef OPENSSL_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);

	}

EXPORT_C 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;

		OPENSSL_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);

	}

EXPORT_C 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;

			}

		}

	}

EXPORT_C void lh_doall(LHASH *lh, LHASH_DOALL_FN_TYPE func)

	{

	doall_util_fn(lh, 0, func, (LHASH_DOALL_ARG_FN_TYPE)0, NULL);

	}

EXPORT_C 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;

	unsigned long hash,nni;

	lh->num_nodes++;

	lh->num_expands++;

	p=(int)lh->p++;

	n1= &(lh->b[p]);

	n2= &(lh->b[p+(int)lh->pmax]);

	*n2=NULL;        /* 27/07/92 - eay - undefined pointer bug */

	nni=lh->num_alloc_nodes;

	for (np= *n1; np != NULL; )

		{

#ifndef OPENSSL_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;

		}

	if ((lh->p) >= lh->pmax)

		{

		j=(int)lh->num_alloc_nodes*2;

		n=(LHASH_NODE **)OPENSSL_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++)/* 26/02/92 eay */

			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;

		}

	}

static void contract(LHASH *lh)

	{

	LHASH_NODE **n,*n1,*np;

	np=lh->b[lh->p+lh->pmax-1];

	lh->b[lh->p+lh->pmax-1]=NULL; /* 24/07-92 - eay - weird but :-( */

	if (lh->p == 0)

		{

		n=(LHASH_NODE **)OPENSSL_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->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 OPENSSL_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.

 */

EXPORT_C 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);

	}

EXPORT_C unsigned long lh_num_items(const LHASH *lh)

	{

	return lh ? lh->num_items : 0;

	}