/* $OpenBSD: lhash.c,v 1.19 2019/05/12 00:09:59 beck Exp $ */

/* 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/opensslconf.h>

#include <openssl/crypto.h>

#include <openssl/lhash.h>

#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;

  if ((ret = calloc(1, sizeof(_LHASH))) == NULL)

    return NULL;

  if ((ret->b = calloc(MIN_NODES, sizeof(LHASH_NODE *))) == NULL) {

    free(ret);

    return 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->pmax = MIN_NODES / 2;

  ret->up_load = UP_LOAD;

  ret->down_load = DOWN_LOAD;

  return (ret);

}

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 = 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;

    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;

  if (lh == NULL)

    return;

  /* 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 */

      /* 22/05/08 - ben - eh? since a is not passed,

       * this should not be needed */

      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 = reallocarray(lh->b, j, sizeof(LHASH_NODE *));

    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 = reallocarray(lh->b, lh->pmax, sizeof(LHASH_NODE *));

    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;

  unsigned long n, v;

  unsigned int r;

  if (c == NULL || *c == '\0')

    return ret;

  n = 0x100;

  while (*c) {

    v = n | *c;

    n += 0x100;

    if ((r = ((v >> 2) ^ v) & 0x0f) != 0)

      ret = (ret << r) | (ret >> (32 - r));

    ret &= 0xFFFFFFFFUL;

    ret ^= v * v;

    c++;

  }

  return (ret >> 16) ^ ret;

}

unsigned long

lh_num_items(const _LHASH *lh)

{

  return lh ? lh->num_items : 0;

}