source: trunk/sys/libcrypto/lhash.c @ 75

/* 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);

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);
        }

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);
        }

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);
        }

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);
        }

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;
        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.
 */
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;
        }