Main Page | Modules | Alphabetical List | Data Structures | File List | Data Fields | Globals

ht_move.c

Go to the documentation of this file.
00001 /*
00002 ** Copyright (C) 2002 by Kevin L. Mitchell <klmitch@mit.edu>
00003 **
00004 ** This library is free software; you can redistribute it and/or
00005 ** modify it under the terms of the GNU Library General Public
00006 ** License as published by the Free Software Foundation; either
00007 ** version 2 of the License, or (at your option) any later version.
00008 **
00009 ** This library is distributed in the hope that it will be useful,
00010 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
00011 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012 ** Library General Public License for more details.
00013 **
00014 ** You should have received a copy of the GNU Library General Public
00015 ** License along with this library; if not, write to the Free
00016 ** Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
00017 ** MA 02111-1307, USA
00018 **
00019 ** @(#)$Id: ht_move.c,v 1.3 2006/07/13 05:36:16 klmitch Exp $
00020 */
00028 #include "dbprim.h"
00029 #include "dbprim_int.h"
00030 
00031 RCSTAG("@(#)$Id: ht_move.c,v 1.3 2006/07/13 05:36:16 klmitch Exp $");
00032 
00033 unsigned long
00034 ht_move(hash_table_t *table, hash_entry_t *entry, db_key_t *key)
00035 {
00036   unsigned long retval;
00037 
00038   initialize_dbpr_error_table(); /* initialize error table */
00039 
00040   if (!ht_verify(table) || !he_verify(entry) || !key) /* verify arguments */
00041     return DB_ERR_BADARGS;
00042 
00043   if (!entry->he_table) /* it's not in a table */
00044     return DB_ERR_UNUSED;
00045   if (entry->he_table != table) /* it's in the wrong table */
00046     return DB_ERR_WRONGTABLE;
00047 
00048   if (table->ht_flags & HASH_FLAG_FREEZE) /* don't mess with frozen tables */
00049     return DB_ERR_FROZEN;
00050 
00051   if (!ht_find(table, 0, key)) /* don't permit duplicates */
00052     return DB_ERR_DUPLICATE;
00053 
00054   /* remove the entry from the table */
00055   if ((retval = ll_remove(&table->ht_table[entry->he_hash], &entry->he_elem)))
00056     return retval;
00057 
00058   /* rekey the entry */
00059   entry->he_key = *key; /* thank goodness for structure copy! */
00060 
00061   /* get the new hash value for the entry */
00062   entry->he_hash =
00063     (*table->ht_func)(table, &entry->he_key) % table->ht_modulus;
00064 
00065   /* Now re-add it to the table */
00066   if ((retval = ll_add(&table->ht_table[entry->he_hash], &entry->he_elem,
00067                        LINK_LOC_HEAD, 0))) {
00068     table->ht_count--; /* decrement the count--don't worry about shrinking */
00069     entry->he_table = 0; /* zero the table pointer */
00070     return DB_ERR_READDFAILED;
00071   }
00072 
00073   return 0;
00074 }

Generated on Sat Jul 15 14:10:33 2006 for DatabasePrimitivesLibrary by  doxygen 1.4.4