gtk/glib/ghash.c
1997-11-24 22:37:52 +00:00

419 lines
8.8 KiB
C

/* GLIB - Library of useful routines for C programming
* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "glib.h"
#define HASH_TABLE_MIN_SIZE 11
#define HASH_TABLE_MAX_SIZE 13845163
typedef struct _GHashNode GHashNode;
typedef struct _GRealHashTable GRealHashTable;
struct _GHashNode
{
gpointer key;
gpointer value;
GHashNode *next;
};
struct _GRealHashTable
{
gint size;
gint nnodes;
gint frozen;
GHashNode **nodes;
GHashFunc hash_func;
GCompareFunc key_compare_func;
};
static void g_hash_table_resize (GHashTable *hash_table);
static gint g_hash_closest_prime (gint num);
static GHashNode* g_hash_node_new (gpointer key,
gpointer value);
static void g_hash_node_destroy (GHashNode *hash_node);
static void g_hash_nodes_destroy (GHashNode *hash_node);
extern gint g_primes[];
extern gint g_nprimes;
static GMemChunk *node_mem_chunk = NULL;
static GHashNode *node_free_list = NULL;
GHashTable*
g_hash_table_new (GHashFunc hash_func,
GCompareFunc key_compare_func)
{
GRealHashTable *hash_table;
g_return_val_if_fail (hash_func != NULL, NULL);
hash_table = g_new (GRealHashTable, 1);
hash_table->size = 0;
hash_table->nnodes = 0;
hash_table->frozen = FALSE;
hash_table->nodes = NULL;
hash_table->hash_func = hash_func;
hash_table->key_compare_func = key_compare_func;
return ((GHashTable*) hash_table);
}
void
g_hash_table_destroy (GHashTable *hash_table)
{
GRealHashTable *rhash_table;
gint i;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
for (i = 0; i < rhash_table->size; i++)
g_hash_nodes_destroy (rhash_table->nodes[i]);
if (rhash_table->nodes)
g_free (rhash_table->nodes);
g_free (rhash_table);
}
}
void
g_hash_table_insert (GHashTable *hash_table,
gpointer key,
gpointer value)
{
GRealHashTable *rhash_table;
GHashNode *node;
guint hash_val;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
if (rhash_table->size == 0)
g_hash_table_resize (hash_table);
hash_val = (* rhash_table->hash_func) (key) % rhash_table->size;
node = rhash_table->nodes[hash_val];
while (node)
{
if ((rhash_table->key_compare_func &&
(* rhash_table->key_compare_func) (node->key, key)) ||
(node->key == key))
{
node->value = value;
return;
}
node = node->next;
}
node = g_hash_node_new (key, value);
node->next = rhash_table->nodes[hash_val];
rhash_table->nodes[hash_val] = node;
rhash_table->nnodes += 1;
g_hash_table_resize (hash_table);
}
}
void
g_hash_table_remove (GHashTable *hash_table,
gpointer key)
{
GRealHashTable *rhash_table;
GHashNode *node;
GHashNode *prev;
guint hash_val;
rhash_table = (GRealHashTable*) hash_table;
if (hash_table && rhash_table->size)
{
hash_val = (* rhash_table->hash_func) (key) % rhash_table->size;
prev = NULL;
node = rhash_table->nodes[hash_val];
while (node)
{
if ((rhash_table->key_compare_func &&
(* rhash_table->key_compare_func) (node->key, key)) ||
(node->key == key))
{
if (prev)
prev->next = node->next;
if (node == rhash_table->nodes[hash_val])
rhash_table->nodes[hash_val] = node->next;
g_hash_node_destroy (node);
rhash_table->nnodes -= 1;
g_hash_table_resize (hash_table);
break;
}
prev = node;
node = node->next;
}
}
}
gpointer
g_hash_table_lookup (GHashTable *hash_table,
const gpointer key)
{
GRealHashTable *rhash_table;
GHashNode *node;
guint hash_val;
rhash_table = (GRealHashTable*) hash_table;
if (hash_table && rhash_table->size)
{
hash_val = (* rhash_table->hash_func) (key) % rhash_table->size;
node = rhash_table->nodes[hash_val];
/* Hash table lookup needs to be fast.
* We therefore remove the extra conditional of testing
* whether to call the key_compare_func or not from
* the inner loop.
*/
if (rhash_table->key_compare_func)
{
while (node)
{
if ((* rhash_table->key_compare_func) (node->key, key))
return node->value;
node = node->next;
}
}
else
{
while (node)
{
if (node->key == key)
return node->value;
node = node->next;
}
}
}
return NULL;
}
void
g_hash_table_freeze (GHashTable *hash_table)
{
GRealHashTable *rhash_table;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
rhash_table->frozen = TRUE;
}
}
void
g_hash_table_thaw (GHashTable *hash_table)
{
GRealHashTable *rhash_table;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
rhash_table->frozen = FALSE;
g_hash_table_resize (hash_table);
}
}
void
g_hash_table_foreach (GHashTable *hash_table,
GHFunc func,
gpointer user_data)
{
GRealHashTable *rhash_table;
GHashNode *node;
gint i;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
for (i = 0; i < rhash_table->size; i++)
{
node = rhash_table->nodes[i];
while (node)
{
(* func) (node->key, node->value, user_data);
node = node->next;
}
}
}
}
static void
g_hash_table_resize (GHashTable *hash_table)
{
GRealHashTable *rhash_table;
GHashNode **new_nodes;
GHashNode *node;
GHashNode *next;
gfloat nodes_per_list;
guint hash_val;
gint new_size;
gint need_resize;
gint i;
if (hash_table)
{
rhash_table = (GRealHashTable*) hash_table;
if (rhash_table->size == 0)
{
rhash_table->size = HASH_TABLE_MIN_SIZE;
rhash_table->nodes = g_new (GHashNode*, rhash_table->size);
for (i = 0; i < rhash_table->size; i++)
rhash_table->nodes[i] = NULL;
}
else if (!rhash_table->frozen)
{
need_resize = FALSE;
nodes_per_list = (gfloat) rhash_table->nnodes / (gfloat) rhash_table->size;
if (nodes_per_list < 0.3)
{
if (rhash_table->size > HASH_TABLE_MIN_SIZE)
need_resize = TRUE;
}
else if (nodes_per_list > 3.0)
{
if (rhash_table->size < HASH_TABLE_MAX_SIZE)
need_resize = TRUE;
}
if (need_resize)
{
new_size = g_hash_closest_prime (rhash_table->nnodes);
if (new_size < HASH_TABLE_MIN_SIZE)
new_size = HASH_TABLE_MIN_SIZE;
else if (new_size > HASH_TABLE_MAX_SIZE)
new_size = HASH_TABLE_MAX_SIZE;
new_nodes = g_new (GHashNode*, new_size);
for (i = 0; i < new_size; i++)
new_nodes[i] = NULL;
for (i = 0; i < rhash_table->size; i++)
{
node = rhash_table->nodes[i];
while (node)
{
next = node->next;
hash_val = (* rhash_table->hash_func) (node->key) % new_size;
node->next = new_nodes[hash_val];
new_nodes[hash_val] = node;
node = next;
}
}
g_free (rhash_table->nodes);
rhash_table->nodes = new_nodes;
rhash_table->size = new_size;
}
}
}
}
static gint
g_hash_closest_prime (gint num)
{
gint i;
for (i = 0; i < g_nprimes; i++)
if ((g_primes[i] - num) > 0)
return g_primes[i];
return g_primes[g_nprimes - 1];
}
static GHashNode*
g_hash_node_new (gpointer key,
gpointer value)
{
GHashNode *hash_node;
if (node_free_list)
{
hash_node = node_free_list;
node_free_list = node_free_list->next;
}
else
{
if (!node_mem_chunk)
node_mem_chunk = g_mem_chunk_new ("hash node mem chunk",
sizeof (GHashNode),
1024, G_ALLOC_ONLY);
hash_node = g_chunk_new (GHashNode, node_mem_chunk);
}
hash_node->key = key;
hash_node->value = value;
hash_node->next = NULL;
return hash_node;
}
static void
g_hash_node_destroy (GHashNode *hash_node)
{
if (hash_node)
{
hash_node->next = node_free_list;
node_free_list = hash_node;
}
}
static void
g_hash_nodes_destroy (GHashNode *hash_node)
{
GHashNode *node;
if (hash_node)
{
node = hash_node;
while (node->next)
node = node->next;
node->next = node_free_list;
node_free_list = hash_node;
}
}