/* Hash tables for Objective C internal structures
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/* Hash tables for Objective C internal structures
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Copyright (C) 1993, 1996, 1997, 2004, 2009, 2010
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Copyright (C) 1993, 1996, 1997, 2004, 2009, 2010
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Free Software Foundation, Inc.
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Free Software Foundation, Inc.
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This file is part of GCC.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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any later version.
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GCC is distributed in the hope that it will be useful,
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GCC 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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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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<http://www.gnu.org/licenses/>. */
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#include "objc-private/common.h"
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#include "objc-private/common.h"
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#include <assert.h> /* For assert. */
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#include <assert.h> /* For assert. */
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#include "objc/runtime.h" /* For objc_calloc. */
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#include "objc/runtime.h" /* For objc_calloc. */
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#include "objc-private/hash.h"
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#include "objc-private/hash.h"
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/* These two macros determine when a hash table is full and
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/* These two macros determine when a hash table is full and
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by how much it should be expanded respectively.
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by how much it should be expanded respectively.
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These equations are percentages. */
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These equations are percentages. */
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#define FULLNESS(cache) \
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#define FULLNESS(cache) \
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((((cache)->size * 75) / 100) <= (cache)->used)
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((((cache)->size * 75) / 100) <= (cache)->used)
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#define EXPANSION(cache) \
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#define EXPANSION(cache) \
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((cache)->size * 2)
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((cache)->size * 2)
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cache_ptr
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cache_ptr
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objc_hash_new (unsigned int size, hash_func_type hash_func,
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objc_hash_new (unsigned int size, hash_func_type hash_func,
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compare_func_type compare_func)
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compare_func_type compare_func)
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{
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{
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cache_ptr cache;
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cache_ptr cache;
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/* Pass me a value greater than 0 and a power of 2. */
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/* Pass me a value greater than 0 and a power of 2. */
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assert (size);
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assert (size);
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assert (! (size & (size - 1)));
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assert (! (size & (size - 1)));
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/* Allocate the cache structure. calloc insures its initialization
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/* Allocate the cache structure. calloc insures its initialization
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for default values. */
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for default values. */
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cache = (cache_ptr) objc_calloc (1, sizeof (struct cache));
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cache = (cache_ptr) objc_calloc (1, sizeof (struct cache));
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assert (cache);
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assert (cache);
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/* Allocate the array of buckets for the cache. calloc initializes
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/* Allocate the array of buckets for the cache. calloc initializes
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all of the pointers to NULL. */
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all of the pointers to NULL. */
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cache->node_table
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cache->node_table
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= (node_ptr *) objc_calloc (size, sizeof (node_ptr));
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= (node_ptr *) objc_calloc (size, sizeof (node_ptr));
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assert (cache->node_table);
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assert (cache->node_table);
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cache->size = size;
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cache->size = size;
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/* This should work for all processor architectures (?). */
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/* This should work for all processor architectures (?). */
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cache->mask = (size - 1);
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cache->mask = (size - 1);
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/* Store the hashing function so that codes can be computed. */
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/* Store the hashing function so that codes can be computed. */
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cache->hash_func = hash_func;
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cache->hash_func = hash_func;
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/* Store the function that compares hash keys to determine if they
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/* Store the function that compares hash keys to determine if they
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are equal. */
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are equal. */
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cache->compare_func = compare_func;
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cache->compare_func = compare_func;
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return cache;
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return cache;
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}
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}
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void
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void
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objc_hash_delete (cache_ptr cache)
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objc_hash_delete (cache_ptr cache)
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{
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{
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node_ptr node;
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node_ptr node;
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node_ptr next_node;
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node_ptr next_node;
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unsigned int i;
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unsigned int i;
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/* Purge all key/value pairs from the table. */
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/* Purge all key/value pairs from the table. */
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/* Step through the nodes one by one and remove every node WITHOUT
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/* Step through the nodes one by one and remove every node WITHOUT
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using objc_hash_next. this makes objc_hash_delete much more
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using objc_hash_next. this makes objc_hash_delete much more
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efficient. */
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efficient. */
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for (i = 0; i < cache->size; i++)
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for (i = 0; i < cache->size; i++)
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{
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{
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if ((node = cache->node_table[i]))
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if ((node = cache->node_table[i]))
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{
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{
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/* An entry in the hash table has been found. Now step
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/* An entry in the hash table has been found. Now step
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through the nodes next in the list and free them. */
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through the nodes next in the list and free them. */
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while ((next_node = node->next))
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while ((next_node = node->next))
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{
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{
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objc_hash_remove (cache,node->key);
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objc_hash_remove (cache,node->key);
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node = next_node;
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node = next_node;
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}
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}
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objc_hash_remove (cache,node->key);
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objc_hash_remove (cache,node->key);
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}
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}
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}
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}
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/* Release the array of nodes and the cache itself. */
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/* Release the array of nodes and the cache itself. */
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objc_free(cache->node_table);
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objc_free(cache->node_table);
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objc_free(cache);
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objc_free(cache);
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}
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}
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void
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void
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objc_hash_add (cache_ptr *cachep, const void *key, void *value)
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objc_hash_add (cache_ptr *cachep, const void *key, void *value)
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{
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{
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size_t indx = (*(*cachep)->hash_func) (*cachep, key);
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size_t indx = (*(*cachep)->hash_func) (*cachep, key);
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node_ptr node = (node_ptr) objc_calloc (1, sizeof (struct cache_node));
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node_ptr node = (node_ptr) objc_calloc (1, sizeof (struct cache_node));
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assert (node);
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assert (node);
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/* Initialize the new node. */
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/* Initialize the new node. */
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node->key = key;
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node->key = key;
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node->value = value;
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node->value = value;
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node->next = (*cachep)->node_table[indx];
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node->next = (*cachep)->node_table[indx];
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/* Debugging. Check the list for another key. */
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/* Debugging. Check the list for another key. */
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#ifdef DEBUG
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#ifdef DEBUG
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{
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{
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node_ptr node1 = (*cachep)->node_table[indx];
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node_ptr node1 = (*cachep)->node_table[indx];
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while (node1)
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while (node1)
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{
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{
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assert (node1->key != key);
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assert (node1->key != key);
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node1 = node1->next;
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node1 = node1->next;
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}
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}
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}
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}
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#endif
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#endif
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/* Install the node as the first element on the list. */
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/* Install the node as the first element on the list. */
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(*cachep)->node_table[indx] = node;
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(*cachep)->node_table[indx] = node;
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/* Bump the number of entries in the cache. */
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/* Bump the number of entries in the cache. */
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++(*cachep)->used;
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++(*cachep)->used;
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/* Check the hash table's fullness. We're going to expand if it is
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/* Check the hash table's fullness. We're going to expand if it is
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above the fullness level. */
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above the fullness level. */
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if (FULLNESS (*cachep))
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if (FULLNESS (*cachep))
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{
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{
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/* The hash table has reached its fullness level. Time to
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/* The hash table has reached its fullness level. Time to
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expand it.
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expand it.
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I'm using a slow method here but is built on other primitive
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I'm using a slow method here but is built on other primitive
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functions thereby increasing its correctness. */
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functions thereby increasing its correctness. */
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node_ptr node1 = NULL;
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node_ptr node1 = NULL;
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cache_ptr new = objc_hash_new (EXPANSION (*cachep),
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cache_ptr new = objc_hash_new (EXPANSION (*cachep),
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(*cachep)->hash_func,
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(*cachep)->hash_func,
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(*cachep)->compare_func);
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(*cachep)->compare_func);
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DEBUG_PRINTF ("Expanding cache %#x from %d to %d\n",
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DEBUG_PRINTF ("Expanding cache %#x from %d to %d\n",
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(int) *cachep, (*cachep)->size, new->size);
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(int) *cachep, (*cachep)->size, new->size);
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/* Copy the nodes from the first hash table to the new one. */
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/* Copy the nodes from the first hash table to the new one. */
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while ((node1 = objc_hash_next (*cachep, node1)))
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while ((node1 = objc_hash_next (*cachep, node1)))
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objc_hash_add (&new, node1->key, node1->value);
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objc_hash_add (&new, node1->key, node1->value);
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/* Trash the old cache. */
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/* Trash the old cache. */
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objc_hash_delete (*cachep);
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objc_hash_delete (*cachep);
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/* Return a pointer to the new hash table. */
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/* Return a pointer to the new hash table. */
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*cachep = new;
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*cachep = new;
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}
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}
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}
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}
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void
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void
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objc_hash_remove (cache_ptr cache, const void *key)
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objc_hash_remove (cache_ptr cache, const void *key)
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{
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{
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size_t indx = (*cache->hash_func) (cache, key);
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size_t indx = (*cache->hash_func) (cache, key);
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node_ptr node = cache->node_table[indx];
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node_ptr node = cache->node_table[indx];
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/* We assume there is an entry in the table. Error if it is
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/* We assume there is an entry in the table. Error if it is
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not. */
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not. */
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assert (node);
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assert (node);
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/* Special case. First element is the key/value pair to be
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/* Special case. First element is the key/value pair to be
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removed. */
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removed. */
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if ((*cache->compare_func) (node->key, key))
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if ((*cache->compare_func) (node->key, key))
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{
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{
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cache->node_table[indx] = node->next;
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cache->node_table[indx] = node->next;
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objc_free(node);
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objc_free(node);
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}
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}
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else
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else
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{
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{
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/* Otherwise, find the hash entry. */
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/* Otherwise, find the hash entry. */
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node_ptr prev = node;
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node_ptr prev = node;
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BOOL removed = NO;
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BOOL removed = NO;
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do
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do
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{
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{
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if ((*cache->compare_func) (node->key, key))
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if ((*cache->compare_func) (node->key, key))
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{
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{
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prev->next = node->next, removed = YES;
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prev->next = node->next, removed = YES;
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objc_free(node);
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objc_free(node);
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}
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}
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else
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else
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prev = node, node = node->next;
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prev = node, node = node->next;
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}
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}
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while (!removed && node);
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while (!removed && node);
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assert (removed);
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assert (removed);
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}
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}
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/* Decrement the number of entries in the hash table. */
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/* Decrement the number of entries in the hash table. */
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--cache->used;
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--cache->used;
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}
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}
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node_ptr
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node_ptr
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objc_hash_next (cache_ptr cache, node_ptr node)
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objc_hash_next (cache_ptr cache, node_ptr node)
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{
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{
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/* If the scan is being started then reset the last node visitied
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/* If the scan is being started then reset the last node visitied
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pointer and bucket index. */
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pointer and bucket index. */
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if (!node)
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if (!node)
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cache->last_bucket = 0;
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cache->last_bucket = 0;
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/* If there is a node visited last then check for another entry in
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/* If there is a node visited last then check for another entry in
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the same bucket. Otherwise step to the next bucket. */
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the same bucket. Otherwise step to the next bucket. */
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if (node)
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if (node)
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{
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{
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if (node->next)
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if (node->next)
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{
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{
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/* There is a node which follows the last node returned.
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/* There is a node which follows the last node returned.
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Step to that node and retun it. */
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Step to that node and retun it. */
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return node->next;
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return node->next;
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}
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}
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else
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else
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++cache->last_bucket;
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++cache->last_bucket;
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}
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}
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/* If the list isn't exhausted then search the buckets for other
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/* If the list isn't exhausted then search the buckets for other
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nodes. */
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nodes. */
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if (cache->last_bucket < cache->size)
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if (cache->last_bucket < cache->size)
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{
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{
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/* Scan the remainder of the buckets looking for an entry at
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/* Scan the remainder of the buckets looking for an entry at
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the head of the list. Return the first item found. */
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the head of the list. Return the first item found. */
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while (cache->last_bucket < cache->size)
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while (cache->last_bucket < cache->size)
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if (cache->node_table[cache->last_bucket])
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if (cache->node_table[cache->last_bucket])
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return cache->node_table[cache->last_bucket];
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return cache->node_table[cache->last_bucket];
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else
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else
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++cache->last_bucket;
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++cache->last_bucket;
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/* No further nodes were found in the hash table. */
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/* No further nodes were found in the hash table. */
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return NULL;
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return NULL;
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}
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}
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else
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else
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return NULL;
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return NULL;
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}
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}
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/* Given KEY, return corresponding value for it in CACHE. Return NULL
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/* Given KEY, return corresponding value for it in CACHE. Return NULL
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if the KEY is not recorded. */
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if the KEY is not recorded. */
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void *
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void *
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objc_hash_value_for_key (cache_ptr cache, const void *key)
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objc_hash_value_for_key (cache_ptr cache, const void *key)
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{
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{
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node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
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node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
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void *retval = NULL;
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void *retval = NULL;
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if (node)
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if (node)
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do
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do
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{
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{
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if ((*cache->compare_func) (node->key, key))
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if ((*cache->compare_func) (node->key, key))
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{
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{
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retval = node->value;
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retval = node->value;
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break;
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break;
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}
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}
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else
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else
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node = node->next;
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node = node->next;
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}
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}
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while (! retval && node);
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while (! retval && node);
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return retval;
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return retval;
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}
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}
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/* Given KEY, return YES if it exists in the CACHE. Return NO if it
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/* Given KEY, return YES if it exists in the CACHE. Return NO if it
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does not */
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does not */
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BOOL
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BOOL
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objc_hash_is_key_in_hash (cache_ptr cache, const void *key)
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objc_hash_is_key_in_hash (cache_ptr cache, const void *key)
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{
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{
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node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
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node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
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if (node)
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if (node)
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do
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do
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{
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{
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if ((*cache->compare_func)(node->key, key))
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if ((*cache->compare_func)(node->key, key))
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return YES;
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return YES;
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else
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else
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node = node->next;
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node = node->next;
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}
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}
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while (node);
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while (node);
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return NO;
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return NO;
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}
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}
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