1  /* Hash table for sequential list, set, and map data type.
       2     Copyright (C) 2006, 2009-2023 Free Software Foundation, Inc.
       3     Written by Bruno Haible <bruno@clisp.org>, 2006.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Common code of
      19     gl_linkedhash_list.c, gl_avltreehash_list.c, gl_rbtreehash_list.c,
      20     gl_linkedhash_set.c, gl_hash_set.c,
      21     gl_linkedhash_map.c, gl_hash_map.c.  */
      22  
      23  #include "gl_anyhash_primes.h"
      24  
      25  /* Resizes the hash table with a new estimated size.  */
      26  static void
      27  hash_resize (CONTAINER_T container, size_t estimate)
      28  {
      29    size_t new_size = next_prime (estimate);
      30  
      31    if (new_size > container->table_size)
      32      {
      33        gl_hash_entry_t *old_table = container->table;
      34        /* Allocate the new table.  */
      35        gl_hash_entry_t *new_table;
      36        size_t i;
      37  
      38        if (size_overflow_p (xtimes (new_size, sizeof (gl_hash_entry_t))))
      39          goto fail;
      40        new_table =
      41          (gl_hash_entry_t *) calloc (new_size, sizeof (gl_hash_entry_t));
      42        if (new_table == NULL)
      43          goto fail;
      44  
      45        /* Iterate through the entries of the old table.  */
      46        for (i = container->table_size; i > 0; )
      47          {
      48            gl_hash_entry_t node = old_table[--i];
      49  
      50            while (node != NULL)
      51              {
      52                gl_hash_entry_t next = node->hash_next;
      53                /* Add the entry to the new table.  */
      54                size_t bucket = node->hashcode % new_size;
      55                node->hash_next = new_table[bucket];
      56                new_table[bucket] = node;
      57  
      58                node = next;
      59              }
      60          }
      61  
      62        container->table = new_table;
      63        container->table_size = new_size;
      64        free (old_table);
      65      }
      66    return;
      67  
      68   fail:
      69    /* Just continue without resizing the table.  */
      70    return;
      71  }
      72  
      73  /* Resizes the hash table if needed, after CONTAINER_COUNT (container) was
      74     incremented.  */
      75  static void
      76  hash_resize_after_add (CONTAINER_T container)
      77  {
      78    size_t count = CONTAINER_COUNT (container);
      79    size_t estimate = xsum (count, count / 2); /* 1.5 * count */
      80    if (estimate > container->table_size)
      81      hash_resize (container, estimate);
      82  }