struct _Slot {
MonoObject *key;
MonoObject *value;
- Slot *next;
};
-static gpointer KEYMARKER_REMOVED = &KEYMARKER_REMOVED;
-
struct _MonoGHashTable {
GHashFunc hash_func;
GEqualFunc key_equal_func;
- Slot **table;
+ Slot *table;
int table_size;
int in_use;
- int threshold;
- int last_rehash;
GDestroyNotify value_destroy_func, key_destroy_func;
MonoGHashGCType gc_type;
MonoGCRootSource source;
static void mono_g_hash_mark (void *addr, MonoGCMarkFunc mark_func, void *gc_data);
#endif
-static Slot*
-new_slot (MonoGHashTable *hash)
-{
- return mg_new (Slot, 1);
-}
-
-static void
-free_slot (MonoGHashTable *hash, Slot *slot)
-{
- mg_free (slot);
-}
-
#if UNUSED
static gboolean
test_prime (int x)
calc_prime (int x)
{
int i;
-
+
for (i = (x & (~1))-1; i< G_MAXINT32; i += 2) {
if (test_prime (i))
return i;
}
#endif
+#define HASH_TABLE_MAX_LOAD_FACTOR 0.7f
+/* We didn't really do compaction before, keep it lenient for now */
+#define HASH_TABLE_MIN_LOAD_FACTOR 0.05f
+/* We triple the table size at rehash time, similar with previous implementation */
+#define HASH_TABLE_RESIZE_RATIO 3
+
+/* Returns position of key or of an empty slot for it */
+static inline int mono_g_hash_table_find_slot (MonoGHashTable *hash, const MonoObject *key)
+{
+ guint i = ((*hash->hash_func) (key)) % hash->table_size;
+ GEqualFunc equal = hash->key_equal_func;
+
+ while (hash->table [i].key && !(*equal) (hash->table [i].key, key)) {
+ i++;
+ if (i == hash->table_size)
+ i = 0;
+ }
+ return i;
+}
+
+
MonoGHashTable *
mono_g_hash_table_new_type (GHashFunc hash_func, GEqualFunc key_equal_func, MonoGHashGCType type, MonoGCRootSource source, const char *msg)
{
MonoGHashTable *hash;
- if (hash_func == NULL)
+ if (!hash_func)
hash_func = g_direct_hash;
- if (key_equal_func == NULL)
+ if (!key_equal_func)
key_equal_func = g_direct_equal;
#ifdef HAVE_SGEN_GC
hash->key_equal_func = key_equal_func;
hash->table_size = g_spaced_primes_closest (1);
- hash->table = mg_new0 (Slot *, hash->table_size);
- hash->last_rehash = hash->table_size;
+ hash->table = mg_new0 (Slot, hash->table_size);
hash->gc_type = type;
hash->source = source;
typedef struct {
MonoGHashTable *hash;
int new_size;
- Slot **table;
+ Slot *table;
} RehashData;
static void*
RehashData *data = (RehashData *)_data;
MonoGHashTable *hash = data->hash;
int current_size, i;
- Slot **table;
+ Slot *old_table;
- /* printf ("Resizing diff=%d slots=%d\n", hash->in_use - hash->last_rehash, hash->table_size); */
- hash->last_rehash = hash->table_size;
current_size = hash->table_size;
hash->table_size = data->new_size;
- /* printf ("New size: %d\n", hash->table_size); */
- table = hash->table;
+ old_table = hash->table;
hash->table = data->table;
- for (i = 0; i < current_size; i++){
- Slot *s, *next;
-
- for (s = table [i]; s != NULL; s = next){
- guint hashcode = ((*hash->hash_func) (s->key)) % hash->table_size;
- next = s->next;
-
- s->next = hash->table [hashcode];
- hash->table [hashcode] = s;
+ for (i = 0; i < current_size; i++) {
+ if (old_table [i].key) {
+ int slot = mono_g_hash_table_find_slot (hash, old_table [i].key);
+ hash->table [slot].key = old_table [i].key;
+ hash->table [slot].value = old_table [i].value;
}
}
- return table;
+ return old_table;
}
static void
{
MONO_REQ_GC_UNSAFE_MODE; //we must run in unsafe mode to make rehash safe
- int diff = ABS (hash->last_rehash - hash->in_use);
RehashData data;
void *old_table G_GNUC_UNUSED; /* unused on Boehm */
- /* These are the factors to play with to change the rehashing strategy */
- /* I played with them with a large range, and could not really get */
- /* something that was too good, maybe the tests are not that great */
- if (!(diff * 0.75 > hash->table_size * 2))
- return;
-
data.hash = hash;
- data.new_size = g_spaced_primes_closest (hash->in_use);
- data.table = mg_new0 (Slot *, data.new_size);
+ /*
+ * Rehash to a size that can fit the current elements. Rehash relative to in_use
+ * to allow also for compaction.
+ */
+ data.new_size = g_spaced_primes_closest (hash->in_use / HASH_TABLE_MAX_LOAD_FACTOR * HASH_TABLE_RESIZE_RATIO);
+ data.table = mg_new0 (Slot, data.new_size);
if (!mono_threads_is_coop_enabled ()) {
old_table = mono_gc_invoke_with_gc_lock (do_rehash, &data);
mono_g_hash_table_size (MonoGHashTable *hash)
{
g_return_val_if_fail (hash != NULL, 0);
-
+
return hash->in_use;
}
mono_g_hash_table_lookup (MonoGHashTable *hash, gconstpointer key)
{
gpointer orig_key, value;
-
+
if (mono_g_hash_table_lookup_extended (hash, key, &orig_key, &value))
return value;
else
gboolean
mono_g_hash_table_lookup_extended (MonoGHashTable *hash, gconstpointer key, gpointer *orig_key, gpointer *value)
{
- GEqualFunc equal;
- Slot *s;
- guint hashcode;
-
+ int slot;
+
g_return_val_if_fail (hash != NULL, FALSE);
- equal = hash->key_equal_func;
-
- hashcode = ((*hash->hash_func) (key)) % hash->table_size;
-
- for (s = hash->table [hashcode]; s != NULL; s = s->next){
- if ((*equal)(s->key, key)){
- *orig_key = s->key;
- *value = s->value;
- return TRUE;
- }
+
+ slot = mono_g_hash_table_find_slot (hash, key);
+
+ if (hash->table [slot].key) {
+ *orig_key = hash->table [slot].key;
+ *value = hash->table [slot].value;
+ return TRUE;
}
+
return FALSE;
}
mono_g_hash_table_foreach (MonoGHashTable *hash, GHFunc func, gpointer user_data)
{
int i;
-
+
g_return_if_fail (hash != NULL);
g_return_if_fail (func != NULL);
- for (i = 0; i < hash->table_size; i++){
- Slot *s;
-
- for (s = hash->table [i]; s != NULL; s = s->next)
- (*func)(s->key, s->value, user_data);
+ for (i = 0; i < hash->table_size; i++) {
+ if (hash->table [i].key)
+ (*func)(hash->table [i].key, hash->table [i].value, user_data);
}
}
mono_g_hash_table_find (MonoGHashTable *hash, GHRFunc predicate, gpointer user_data)
{
int i;
-
+
g_return_val_if_fail (hash != NULL, NULL);
g_return_val_if_fail (predicate != NULL, NULL);
- for (i = 0; i < hash->table_size; i++){
- Slot *s;
-
- for (s = hash->table [i]; s != NULL; s = s->next)
- if ((*predicate)(s->key, s->value, user_data))
- return s->value;
+ for (i = 0; i < hash->table_size; i++) {
+ if (hash->table [i].key && (*predicate)(hash->table [i].key, hash->table [i].value, user_data))
+ return hash->table [i].value;
}
return NULL;
}
gboolean
mono_g_hash_table_remove (MonoGHashTable *hash, gconstpointer key)
{
- GEqualFunc equal;
- Slot *s, *last;
- guint hashcode;
-
+ int slot, last_clear_slot;
+
g_return_val_if_fail (hash != NULL, FALSE);
- equal = hash->key_equal_func;
-
- hashcode = ((*hash->hash_func)(key)) % hash->table_size;
- last = NULL;
- for (s = hash->table [hashcode]; s != NULL; s = s->next){
- if ((*equal)(s->key, key)){
- if (hash->key_destroy_func != NULL)
- (*hash->key_destroy_func)(s->key);
- if (hash->value_destroy_func != NULL)
- (*hash->value_destroy_func)(s->value);
- if (last == NULL)
- hash->table [hashcode] = s->next;
- else
- last->next = s->next;
- free_slot (hash, s);
- hash->in_use--;
- return TRUE;
+ slot = mono_g_hash_table_find_slot (hash, key);
+
+ if (!hash->table [slot].key)
+ return FALSE;
+
+ if (hash->key_destroy_func)
+ (*hash->key_destroy_func)(hash->table [slot].key);
+ hash->table [slot].key = NULL;
+ if (hash->value_destroy_func)
+ (*hash->value_destroy_func)(hash->table [slot].value);
+ hash->table [slot].value = NULL;
+ hash->in_use--;
+
+ /*
+ * When we insert in the hashtable, if the required position is occupied we
+ * consecutively try out following positions. In order to be able to find
+ * if a key exists or not in the array (without traversing the entire hash)
+ * we maintain the constraint that there can be no free slots between two
+ * entries that are hashed to the same position. This means that, at search
+ * time, when we encounter a free slot we can stop looking for collissions.
+ * Similarly, at remove time, we need to shift all following slots to their
+ * normal slot, until we reach an empty slot.
+ */
+ last_clear_slot = slot;
+ slot = (slot + 1) % hash->table_size;
+ while (hash->table [slot].key) {
+ guint hashcode = ((*hash->hash_func)(hash->table [slot].key)) % hash->table_size;
+ /*
+ * We try to move the current element to last_clear_slot, but only if
+ * it brings it closer to its normal position (hashcode)
+ */
+ if ((last_clear_slot < slot && (hashcode > slot || hashcode <= last_clear_slot)) ||
+ (last_clear_slot > slot && (hashcode > slot && hashcode <= last_clear_slot))) {
+ hash->table [last_clear_slot].key = hash->table [slot].key;
+ hash->table [last_clear_slot].value = hash->table [slot].value;
+ hash->table [slot].key = NULL;
+ hash->table [slot].value = NULL;
+ last_clear_slot = slot;
}
- last = s;
+ slot++;
+ if (slot == hash->table_size)
+ slot = 0;
}
- return FALSE;
+ return TRUE;
}
guint
{
int i;
int count = 0;
-
+
g_return_val_if_fail (hash != NULL, 0);
g_return_val_if_fail (func != NULL, 0);
- for (i = 0; i < hash->table_size; i++){
- Slot *s, *last;
-
- last = NULL;
- for (s = hash->table [i]; s != NULL; ){
- if ((*func)(s->key, s->value, user_data)){
- Slot *n;
-
- if (hash->key_destroy_func != NULL)
- (*hash->key_destroy_func)(s->key);
- if (hash->value_destroy_func != NULL)
- (*hash->value_destroy_func)(s->value);
- if (last == NULL){
- hash->table [i] = s->next;
- n = s->next;
- } else {
- last->next = s->next;
- n = last->next;
- }
- free_slot (hash, s);
- hash->in_use--;
- count++;
- s = n;
- } else {
- last = s;
- s = s->next;
- }
+ for (i = 0; i < hash->table_size; i++) {
+ if (hash->table [i].key && (*func)(hash->table [i].key, hash->table [i].value, user_data)) {
+ mono_g_hash_table_remove (hash, hash->table [i].key);
+ count++;
+ /* Retry current slot in case the removal shifted elements */
+ i--;
}
}
- if (count > 0)
+ if (hash->in_use < hash->table_size * HASH_TABLE_MIN_LOAD_FACTOR)
rehash (hash);
return count;
}
mono_g_hash_table_destroy (MonoGHashTable *hash)
{
int i;
-
+
g_return_if_fail (hash != NULL);
#ifdef HAVE_SGEN_GC
mono_gc_deregister_root ((char*)hash);
#endif
- for (i = 0; i < hash->table_size; i++){
- Slot *s, *next;
-
- for (s = hash->table [i]; s != NULL; s = next){
- next = s->next;
-
- if (hash->key_destroy_func != NULL)
- (*hash->key_destroy_func)(s->key);
- if (hash->value_destroy_func != NULL)
- (*hash->value_destroy_func)(s->value);
- free_slot (hash, s);
+ for (i = 0; i < hash->table_size; i++) {
+ if (hash->table [i].key != NULL) {
+ if (hash->key_destroy_func)
+ (*hash->key_destroy_func)(hash->table [i].key);
+ if (hash->value_destroy_func)
+ (*hash->value_destroy_func)(hash->table [i].value);
}
}
mg_free (hash->table);
static void
mono_g_hash_table_insert_replace (MonoGHashTable *hash, gpointer key, gpointer value, gboolean replace)
{
- guint hashcode;
- Slot *s;
- GEqualFunc equal;
-
+ int slot;
g_return_if_fail (hash != NULL);
- equal = hash->key_equal_func;
- if (hash->in_use >= hash->threshold)
+ if (hash->in_use > (hash->table_size * HASH_TABLE_MAX_LOAD_FACTOR))
rehash (hash);
- hashcode = ((*hash->hash_func) (key)) % hash->table_size;
- for (s = hash->table [hashcode]; s != NULL; s = s->next){
- if ((*equal) (s->key, key)){
- if (replace){
- if (hash->key_destroy_func != NULL)
- (*hash->key_destroy_func)(s->key);
- s->key = (MonoObject *)key;
- }
- if (hash->value_destroy_func != NULL)
- (*hash->value_destroy_func) (s->value);
- s->value = (MonoObject *)value;
- return;
+ slot = mono_g_hash_table_find_slot (hash, key);
+
+ if (hash->table [slot].key) {
+ if (replace) {
+ if (hash->key_destroy_func)
+ (*hash->key_destroy_func)(hash->table [slot].key);
+ hash->table [slot].key = (MonoObject *)key;
}
+ if (hash->value_destroy_func)
+ (*hash->value_destroy_func) (hash->table [slot].value);
+ hash->table [slot].value = (MonoObject *)value;
+ } else {
+ hash->table [slot].key = (MonoObject *)key;
+ hash->table [slot].value = (MonoObject *)value;
+ hash->in_use++;
}
- s = new_slot (hash);
- s->key = (MonoObject *)key;
- s->value = (MonoObject *)value;
- s->next = hash->table [hashcode];
- hash->table [hashcode] = s;
- hash->in_use++;
}
void
}
void
-mono_g_hash_table_print_stats (MonoGHashTable *table)
+mono_g_hash_table_print_stats (MonoGHashTable *hash)
{
- int i, chain_size, max_chain_size;
- Slot *node;
-
- max_chain_size = 0;
- for (i = 0; i < table->table_size; i++) {
- chain_size = 0;
- for (node = table->table [i]; node; node = node->next)
- chain_size ++;
- max_chain_size = MAX(max_chain_size, chain_size);
- }
+ int i = 0, chain_size = 0, max_chain_size = 0;
+ gboolean wrapped_around = FALSE;
+
+ while (TRUE) {
+ if (hash->table [i].key) {
+ chain_size++;
+ } else {
+ max_chain_size = MAX(max_chain_size, chain_size);
+ chain_size = 0;
+ if (wrapped_around)
+ break;
+ }
- printf ("Size: %d Table Size: %d Max Chain Length: %d\n", table->in_use, table->table_size, max_chain_size);
+ if (i == (hash->table_size - 1)) {
+ wrapped_around = TRUE;
+ i = 0;
+ } else {
+ i++;
+ }
+ }
+ /* Rehash to a size that can fit the current elements */
+ printf ("Size: %d Table Size: %d Max Chain Length: %d\n", hash->in_use, hash->table_size, max_chain_size);
}
#ifdef HAVE_SGEN_GC
static void
mono_g_hash_mark (void *addr, MonoGCMarkFunc mark_func, void *gc_data)
{
- MonoGHashTable *table = (MonoGHashTable*)addr;
- Slot *node;
+ MonoGHashTable *hash = (MonoGHashTable*)addr;
int i;
- if (table->gc_type == MONO_HASH_KEY_GC) {
- for (i = 0; i < table->table_size; i++) {
- for (node = table->table [i]; node; node = node->next) {
- if (node->key)
- mark_func (&node->key, gc_data);
- }
- }
- } else if (table->gc_type == MONO_HASH_VALUE_GC) {
- for (i = 0; i < table->table_size; i++) {
- for (node = table->table [i]; node; node = node->next) {
- if (node->value)
- mark_func (&node->value, gc_data);
- }
- }
- } else if (table->gc_type == MONO_HASH_KEY_VALUE_GC) {
- for (i = 0; i < table->table_size; i++) {
- for (node = table->table [i]; node; node = node->next) {
- if (node->key)
- mark_func (&node->key, gc_data);
- if (node->value)
- mark_func (&node->value, gc_data);
- }
- }
+ for (i = 0; i < hash->table_size; i++) {
+ if (hash->gc_type & MONO_HASH_KEY_GC && hash->table [i].key)
+ mark_func (&hash->table [i].key, gc_data);
+ if (hash->gc_type & MONO_HASH_VALUE_GC && hash->table [i].value)
+ mark_func (&hash->table [i].value, gc_data);
}
}
-
+
#endif
projects / mono.git / commitdiff