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Commit 57d75eeb by Nicola Pero Committed by Nicola Pero
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In libobjc/: 2010-12-21 Nicola Pero <nicola.pero@meta-innovation.com> 

In libobjc/:
2010-12-21  Nicola Pero  <nicola.pero@meta-innovation.com>

	* hash.c: Tidied up comments and indentation.  No code changes.

From-SVN: r168110
parent d4d92cd3
Showing with 154 additions and 137 deletions
libobjc/ChangeLog
2010-12-21 Nicola Pero <nicola.pero@meta-innovation.com>
* hash.c: Tidied up comments and indentation. No code changes.
2010-12-19 Nicola Pero <nicola.pero@meta-innovation.com>
PR libobjc/47012
......
libobjc/hash.c
......@@ -23,12 +23,12 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "objc-private/common.h"
#include <assert.h> /* For assert */
#include <assert.h> /* For assert. */
#include "objc/runtime.h" /* For objc_calloc */
#include "objc/thr.h" /* Required by objc-private/runtime.h. */
#include "objc/runtime.h" /* For objc_calloc. */
#include "objc/thr.h" /* Required by objc-private/runtime.h. */
#include "objc-private/hash.h"
#include "objc-private/runtime.h" /* for DEBUG_PRINTF */
#include "objc-private/runtime.h" /* for DEBUG_PRINTF. */
/* These two macros determine when a hash table is full and
by how much it should be expanded respectively.
......@@ -49,27 +49,27 @@ objc_hash_new (unsigned int size, hash_func_type hash_func,
assert (size);
assert (! (size & (size - 1)));
/* Allocate the cache structure. calloc insures
its initialization for default values. */
/* Allocate the cache structure. calloc insures its initialization
for default values. */
cache = (cache_ptr) objc_calloc (1, sizeof (struct cache));
assert (cache);
/* Allocate the array of buckets for the cache.
calloc initializes all of the pointers to NULL. */
/* Allocate the array of buckets for the cache. calloc initializes
all of the pointers to NULL. */
cache->node_table
= (node_ptr *) objc_calloc (size, sizeof (node_ptr));
assert (cache->node_table);
cache->size = size;
/* This should work for all processor architectures? */
/* This should work for all processor architectures (?). */
cache->mask = (size - 1);
/* Store the hashing function so that codes can be computed. */
cache->hash_func = hash_func;
/* Store the function that compares hash keys to
determine if they are equal. */
/* Store the function that compares hash keys to determine if they
are equal. */
cache->compare_func = compare_func;
return cache;
......@@ -85,19 +85,22 @@ objc_hash_delete (cache_ptr cache)
/* Purge all key/value pairs from the table. */
/* Step through the nodes one by one and remove every node WITHOUT
using objc_hash_next. this makes objc_hash_delete much more efficient. */
for (i = 0;i < cache->size;i++) {
if ((node = cache->node_table[i])) {
/* an entry in the hash table has been found, now step through the
nodes next in the list and free them. */
while ((next_node = node->next)) {
objc_hash_remove (cache,node->key);
node = next_node;
}
objc_hash_remove (cache,node->key);
using objc_hash_next. this makes objc_hash_delete much more
efficient. */
for (i = 0; i < cache->size; i++)
{
if ((node = cache->node_table[i]))
{
/* An entry in the hash table has been found. Now step
through the nodes next in the list and free them. */
while ((next_node = node->next))
{
objc_hash_remove (cache,node->key);
node = next_node;
}
objc_hash_remove (cache,node->key);
}
}
}
/* Release the array of nodes and the cache itself. */
objc_free(cache->node_table);
......@@ -108,10 +111,9 @@ objc_hash_delete (cache_ptr cache)
void
objc_hash_add (cache_ptr *cachep, const void *key, void *value)
{
size_t indx = (*(*cachep)->hash_func)(*cachep, key);
size_t indx = (*(*cachep)->hash_func) (*cachep, key);
node_ptr node = (node_ptr) objc_calloc (1, sizeof (struct cache_node));
assert (node);
/* Initialize the new node. */
......@@ -119,16 +121,15 @@ objc_hash_add (cache_ptr *cachep, const void *key, void *value)
node->value = value;
node->next = (*cachep)->node_table[indx];
/* Debugging.
Check the list for another key. */
/* Debugging. Check the list for another key. */
#ifdef DEBUG
{ node_ptr node1 = (*cachep)->node_table[indx];
while (node1) {
assert (node1->key != key);
node1 = node1->next;
}
{
node_ptr node1 = (*cachep)->node_table[indx];
while (node1)
{
assert (node1->key != key);
node1 = node1->next;
}
}
#endif
......@@ -137,69 +138,72 @@ objc_hash_add (cache_ptr *cachep, const void *key, void *value)
/* Bump the number of entries in the cache. */
++(*cachep)->used;
/* Check the hash table's fullness. We're going
to expand if it is above the fullness level. */
if (FULLNESS (*cachep)) {
/* The hash table has reached its fullness level. Time to
expand it.
I'm using a slow method here but is built on other
primitive functions thereby increasing its
correctness. */
node_ptr node1 = NULL;
cache_ptr new = objc_hash_new (EXPANSION (*cachep),
(*cachep)->hash_func,
(*cachep)->compare_func);
DEBUG_PRINTF ("Expanding cache %#x from %d to %d\n",
(int) *cachep, (*cachep)->size, new->size);
/* Copy the nodes from the first hash table to the new one. */
while ((node1 = objc_hash_next (*cachep, node1)))
objc_hash_add (&new, node1->key, node1->value);
/* Trash the old cache. */
objc_hash_delete (*cachep);
/* Return a pointer to the new hash table. */
*cachep = new;
}
/* Check the hash table's fullness. We're going to expand if it is
above the fullness level. */
if (FULLNESS (*cachep))
{
/* The hash table has reached its fullness level. Time to
expand it.
I'm using a slow method here but is built on other primitive
functions thereby increasing its correctness. */
node_ptr node1 = NULL;
cache_ptr new = objc_hash_new (EXPANSION (*cachep),
(*cachep)->hash_func,
(*cachep)->compare_func);
DEBUG_PRINTF ("Expanding cache %#x from %d to %d\n",
(int) *cachep, (*cachep)->size, new->size);
/* Copy the nodes from the first hash table to the new one. */
while ((node1 = objc_hash_next (*cachep, node1)))
objc_hash_add (&new, node1->key, node1->value);
/* Trash the old cache. */
objc_hash_delete (*cachep);
/* Return a pointer to the new hash table. */
*cachep = new;
}
}
void
objc_hash_remove (cache_ptr cache, const void *key)
{
size_t indx = (*cache->hash_func)(cache, key);
size_t indx = (*cache->hash_func) (cache, key);
node_ptr node = cache->node_table[indx];
/* We assume there is an entry in the table. Error if it is not. */
/* We assume there is an entry in the table. Error if it is
not. */
assert (node);
/* Special case. First element is the key/value pair to be removed. */
if ((*cache->compare_func)(node->key, key)) {
cache->node_table[indx] = node->next;
objc_free(node);
} else {
/* Otherwise, find the hash entry. */
node_ptr prev = node;
BOOL removed = NO;
do {
if ((*cache->compare_func)(node->key, key)) {
prev->next = node->next, removed = YES;
objc_free(node);
} else
prev = node, node = node->next;
} while (! removed && node);
assert (removed);
}
/* Special case. First element is the key/value pair to be
removed. */
if ((*cache->compare_func) (node->key, key))
{
cache->node_table[indx] = node->next;
objc_free(node);
}
else
{
/* Otherwise, find the hash entry. */
node_ptr prev = node;
BOOL removed = NO;
do
{
if ((*cache->compare_func) (node->key, key))
{
prev->next = node->next, removed = YES;
objc_free(node);
}
else
prev = node, node = node->next;
}
while (!removed && node);
assert (removed);
}
/* Decrement the number of entries in the hash table. */
--cache->used;
}
......@@ -208,76 +212,85 @@ objc_hash_remove (cache_ptr cache, const void *key)
node_ptr
objc_hash_next (cache_ptr cache, node_ptr node)
{
/* If the scan is being started then reset the last node
visitied pointer and bucket index. */
if (! node)
/* If the scan is being started then reset the last node visitied
pointer and bucket index. */
if (!node)
cache->last_bucket = 0;
/* If there is a node visited last then check for another
entry in the same bucket; Otherwise step to the next bucket. */
if (node) {
if (node->next)
/* There is a node which follows the last node
returned. Step to that node and retun it. */
return node->next;
else
++cache->last_bucket;
}
/* If the list isn't exhausted then search the buckets for
other nodes. */
if (cache->last_bucket < cache->size) {
/* Scan the remainder of the buckets looking for an entry
at the head of the list. Return the first item found. */
while (cache->last_bucket < cache->size)
if (cache->node_table[cache->last_bucket])
return cache->node_table[cache->last_bucket];
/* If there is a node visited last then check for another entry in
the same bucket. Otherwise step to the next bucket. */
if (node)
{
if (node->next)
{
/* There is a node which follows the last node returned.
Step to that node and retun it. */
return node->next;
}
else
++cache->last_bucket;
++cache->last_bucket;
}
/* No further nodes were found in the hash table. */
return NULL;
} else
/* If the list isn't exhausted then search the buckets for other
nodes. */
if (cache->last_bucket < cache->size)
{
/* Scan the remainder of the buckets looking for an entry at
the head of the list. Return the first item found. */
while (cache->last_bucket < cache->size)
if (cache->node_table[cache->last_bucket])
return cache->node_table[cache->last_bucket];
else
++cache->last_bucket;
/* No further nodes were found in the hash table. */
return NULL;
}
else
return NULL;
}
/* Given KEY, return corresponding value for it in CACHE.
Return NULL if the KEY is not recorded. */
/* Given KEY, return corresponding value for it in CACHE. Return NULL
if the KEY is not recorded. */
void *
objc_hash_value_for_key (cache_ptr cache, const void *key)
{
node_ptr node = cache->node_table[(*cache->hash_func)(cache, key)];
node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
void *retval = NULL;
if (node)
do {
if ((*cache->compare_func)(node->key, key)) {
retval = node->value;
break;
} else
node = node->next;
} while (! retval && node);
do
{
if ((*cache->compare_func) (node->key, key))
{
retval = node->value;
break;
}
else
node = node->next;
}
while (! retval && node);
return retval;
}
/* Given KEY, return YES if it exists in the CACHE.
Return NO if it does not */
/* Given KEY, return YES if it exists in the CACHE. Return NO if it
does not */
BOOL
objc_hash_is_key_in_hash (cache_ptr cache, const void *key)
{
node_ptr node = cache->node_table[(*cache->hash_func)(cache, key)];
node_ptr node = cache->node_table[(*cache->hash_func) (cache, key)];
if (node)
do {
if ((*cache->compare_func)(node->key, key))
do
{
if ((*cache->compare_func)(node->key, key))
return YES;
else
node = node->next;
} while (node);
else
node = node->next;
}
while (node);
return NO;
}
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