text: /* 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 = OPENSSL_malloc(sizeof(_LHASH))) == NULL)
          goto err0;
      if ((ret->b = 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;
  
      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 = (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 void *arg)
  {
      const char *c = (const char *)arg;
      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;
  }
  