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/* |
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** Copyright (C) 2002 by Kevin L. Mitchell <klmitch@mit.edu> |
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** |
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** This library is free software; you can redistribute it and/or |
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** modify it under the terms of the GNU Library General Public |
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** License as published by the Free Software Foundation; either |
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** version 2 of the License, or (at your option) any later version. |
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** |
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** This library is distributed in the hope that it will be useful, |
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** but WITHOUT ANY WARRANTY; without even the implied warranty of |
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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** Library General Public License for more details. |
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** |
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** You should have received a copy of the GNU Library General Public |
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** License along with this library; if not, write to the Free |
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** Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
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** MA 02111-1307, USA |
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** |
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** @(#)$Id: ht_init.c,v 1.2 2003/06/12 01:10:04 klmitch Exp $ |
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*/ |
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#include <errno.h> |
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#include <stdlib.h> |
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|
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#include "dbprim.h" |
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#include "dbprim_int.h" |
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|
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RCSTAG("@(#)$Id: ht_init.c,v 1.2 2003/06/12 01:10:04 klmitch Exp $"); |
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|
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/** \ingroup dbprim_hash |
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* \brief Dynamically initialize a hash table. |
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* |
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* This function dynamically initializes a hash table. |
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* |
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* \param table A pointer to a #hash_table_t to be initialized. |
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* \param flags A bit-wise OR of #HASH_FLAG_AUTOGROW and |
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* #HASH_FLAG_AUTOSHRINK. If neither behavior is |
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* desired, use 0. |
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* \param func A #hash_func_t function pointer for a hash function. |
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* \param comp A #hash_comp_t function pointer for a comparison |
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* function. |
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* \param resize |
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* A #hash_resize_t function pointer for determining |
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* whether resizing is permitted and/or for notification |
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* of the resize. |
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* \param extra Extra pointer data that should be associated with the |
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* hash table. |
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* \param init_mod |
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* An initial modulus for the table. This will |
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* presumably be extracted by ht_modulus() in a previous |
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* invocation of the application. A 0 value is valid. |
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* |
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* \retval DB_ERR_BADARGS An invalid argument was given. |
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* \retval ENOMEM Unable to allocate memory. |
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*/ |
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unsigned long |
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ht_init(hash_table_t *table, unsigned long flags, hash_func_t func, |
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hash_comp_t comp, hash_resize_t resize, void *extra, |
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unsigned long init_mod) |
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{ |
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int i; |
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unsigned long retval; |
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|
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initialize_dbpr_error_table(); /* set up error tables */ |
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|
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if (!table || !func || !comp) /* verify arguments */ |
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return DB_ERR_BADARGS; |
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|
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/* initialize the table */ |
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table->ht_flags = flags & (HASH_FLAG_AUTOGROW | HASH_FLAG_AUTOSHRINK); |
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table->ht_modulus = _hash_prime(init_mod); |
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table->ht_count = 0; |
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table->ht_rollover = _hash_rollover(table->ht_modulus); |
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table->ht_rollunder = _hash_rollunder(table->ht_modulus); |
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table->ht_table = 0; |
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table->ht_func = func; |
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table->ht_comp = comp; |
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table->ht_resize = resize; |
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table->ht_extra = extra; |
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|
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if (table->ht_modulus) { /* have an initial size? */ |
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if (!(table->ht_table = |
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(link_head_t *)malloc(table->ht_modulus * sizeof(link_head_t)))) |
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return errno; /* failed to allocate memory? */ |
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|
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for (i = 0; i < table->ht_modulus; i++) /* initialize the listhead array */ |
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if ((retval = ll_init(&table->ht_table[i], table))) { |
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free(table->ht_table); |
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return retval; |
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} |
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} |
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|
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table->ht_magic = HASH_TABLE_MAGIC; /* set the magic number */ |
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|
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return 0; |
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} |
