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arts/flow/gsl/gslglibhash.cpp

150 lines
4.3 KiB

/* GSL Glib Hashtable implementation
* Copyright (C) 2001 Stefan Westerfeld
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "gslglib.h"
#include <list>
#include <map>
using std::list;
using std::pair;
using std::map;
/*
* this uses a map of list to emulate somewhat hashtable like behaviour - note
* that insert and remove are O(log N) due to the use of a map, instead of
* ~ O(1) which they would be for a "real" hashtable
*/
struct _GHashTable
{
GHashFunc hashFunc;
GEqualFunc equalFunc;
map<guint /*hashvalue for key*/, list< pair<gpointer,gpointer> > /*(key,value) pairs*/> nodes;
/*Con*/ _GHashTable (GHashFunc hf, GEqualFunc ef) :
hashFunc(hf), equalFunc(ef) { }
};
GHashTable* g_hash_table_new (GHashFunc hash_func,
GEqualFunc key_equal_func)
{
return new GHashTable (hash_func?hash_func:g_direct_hash, key_equal_func?key_equal_func:g_direct_equal);
}
void g_hash_table_destroy (GHashTable *hash_table)
{
g_return_if_fail (hash_table != NULL);
delete hash_table;
}
void g_hash_table_insert (GHashTable *hash_table,
gpointer key,
gpointer value)
{
g_return_if_fail (hash_table != NULL);
guint hashvalue = hash_table->hashFunc (key);
list< pair<gpointer,gpointer> >& bucket = hash_table->nodes[hashvalue];
list< pair<gpointer,gpointer> >::iterator i;
for (i = bucket.begin(); i != bucket.end(); i++)
{
if (hash_table->equalFunc(i->first, key))
{
if (value || TRUE)
{
i->second = value; /* overwrite old hash value */
return;
}
else
{
bucket.erase(i); /* remove value */
if (bucket.empty()) /* remove bucket if this was the only value */
hash_table->nodes.erase (hashvalue);
return;
}
}
}
if (value)
hash_table->nodes[hashvalue].push_back(std::make_pair (key, value));
}
gpointer g_hash_table_lookup (GHashTable *hash_table,
gconstpointer key)
{
g_return_val_if_fail (hash_table != NULL, NULL);
guint hashvalue = hash_table->hashFunc (key);
list< pair<gpointer,gpointer> >& bucket = hash_table->nodes[hashvalue];
list< pair<gpointer,gpointer> >::iterator i;
for (i = bucket.begin(); i != bucket.end(); i++)
{
if (hash_table->equalFunc(i->first, key))
return i->second;
}
return 0;
}
gboolean g_hash_table_remove (GHashTable *hash_table,
gconstpointer key)
{
g_return_val_if_fail (hash_table != NULL, FALSE);
guint hashvalue = hash_table->hashFunc (key);
list< pair<gpointer,gpointer> >& bucket = hash_table->nodes[hashvalue];
list< pair<gpointer,gpointer> >::iterator i;
for (i = bucket.begin(); i != bucket.end(); i++)
{
if (hash_table->equalFunc(i->first, key))
{
bucket.erase (i);
if (bucket.empty()) /* remove bucket if this was the only value */
hash_table->nodes.erase (hashvalue);
return true;
}
}
return false;
}
void g_hash_table_foreach (GHashTable *hash_table,
GHFunc func,
gpointer user_data)
{
map<guint, list< pair<gpointer,gpointer> > >::iterator bi;
g_return_if_fail (hash_table != NULL);
/* for all buckets */
for (bi = hash_table->nodes.begin (); bi != hash_table->nodes.end (); bi++)
{
list< pair<gpointer,gpointer> >& bucket = bi->second;
list< pair<gpointer,gpointer> >::iterator i;
/* for each element in the current bucket */
for (i = bucket.begin(); i != bucket.end(); i++)
func ((void*) i->first, (void*) i->second, user_data);
}
}