Improve plist_dict_set_item performance for large dictionaries with hash table
diff --git a/src/bplist.c b/src/bplist.c
index 9cc380c..124b024 100644
--- a/src/bplist.c
+++ b/src/bplist.c
@@ -1156,7 +1156,7 @@
//list of objects
objects = ptr_array_new(256);
//hashtable to write only once same nodes
- ref_table = hash_table_new(plist_data_hash, plist_data_compare);
+ ref_table = hash_table_new(plist_data_hash, plist_data_compare, free);
//serialize plist
ser_s.objects = objects;
diff --git a/src/hashtable.c b/src/hashtable.c
index 3568f3c..dd6dbfc 100644
--- a/src/hashtable.c
+++ b/src/hashtable.c
@@ -2,7 +2,7 @@
* hashtable.c
* really simple hash table implementation
*
- * Copyright (c) 2011 Nikias Bassen, All Rights Reserved.
+ * Copyright (c) 2011-2016 Nikias Bassen, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -20,7 +20,7 @@
*/
#include "hashtable.h"
-hashtable_t* hash_table_new(hash_func_t hash_func, compare_func_t compare_func)
+hashtable_t* hash_table_new(hash_func_t hash_func, compare_func_t compare_func, free_func_t free_func)
{
hashtable_t* ht = (hashtable_t*)malloc(sizeof(hashtable_t));
int i;
@@ -30,6 +30,7 @@
ht->count = 0;
ht->hash_func = hash_func;
ht->compare_func = compare_func;
+ ht->free_func = free_func;
return ht;
}
@@ -42,7 +43,9 @@
if (ht->entries[i]) {
hashentry_t* e = ht->entries[i];
while (e) {
- free(e->value);
+ if (ht->free_func) {
+ ht->free_func(e->value);
+ }
hashentry_t* old = e;
e = e->next;
free(old);
@@ -104,3 +107,34 @@
}
return NULL;
}
+
+void hash_table_remove(hashtable_t* ht, void *key)
+{
+ if (!ht || !key) return;
+
+ unsigned int hash = ht->hash_func(key);
+
+ int idx0 = hash & 0xFFF;
+
+ // get the idx0 list
+ hashentry_t* e = ht->entries[idx0];
+ hashentry_t* last = e;
+ while (e) {
+ if (ht->compare_func(e->key, key)) {
+ // found element, remove it from the list
+ hashentry_t* old = e;
+ if (e == ht->entries[idx0]) {
+ ht->entries[idx0] = e->next;
+ } else {
+ last->next = e->next;
+ }
+ if (ht->free_func) {
+ ht->free_func(old->value);
+ }
+ free(old);
+ return;
+ }
+ last = e;
+ e = e->next;
+ }
+}
diff --git a/src/hashtable.h b/src/hashtable.h
index 60a40ab..42d7b93 100644
--- a/src/hashtable.h
+++ b/src/hashtable.h
@@ -2,7 +2,7 @@
* hashtable.h
* header file for really simple hash table implementation
*
- * Copyright (c) 2011 Nikias Bassen, All Rights Reserved.
+ * Copyright (c) 2011-2016 Nikias Bassen, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -30,18 +30,21 @@
typedef unsigned int(*hash_func_t)(const void* key);
typedef int (*compare_func_t)(const void *a, const void *b);
+typedef void (*free_func_t)(void *ptr);
typedef struct hashtable_t {
hashentry_t *entries[4096];
size_t count;
hash_func_t hash_func;
compare_func_t compare_func;
+ free_func_t free_func;
} hashtable_t;
-hashtable_t* hash_table_new(hash_func_t hash_func, compare_func_t compare_func);
+hashtable_t* hash_table_new(hash_func_t hash_func, compare_func_t compare_func, free_func_t free_func);
void hash_table_destroy(hashtable_t *ht);
void hash_table_insert(hashtable_t* ht, void *key, void *value);
void* hash_table_lookup(hashtable_t* ht, void *key);
+void hash_table_remove(hashtable_t* ht, void *key);
#endif
diff --git a/src/plist.c b/src/plist.c
index a3d88b9..6a267eb 100644
--- a/src/plist.c
+++ b/src/plist.c
@@ -37,6 +37,7 @@
#include <node.h>
#include <node_iterator.h>
+#include <hashtable.h>
extern void plist_xml_init(void);
extern void plist_xml_deinit(void);
@@ -148,6 +149,31 @@
return data;
}
+static unsigned int dict_key_hash(const void *data)
+{
+ plist_data_t keydata = (plist_data_t)data;
+ unsigned int hash = 5381;
+ size_t i;
+ char *str = keydata->strval;
+ for (i = 0; i < keydata->length; str++, i++) {
+ hash = ((hash << 5) + hash) + *str;
+ }
+ return hash;
+}
+
+static int dict_key_compare(const void* a, const void* b)
+{
+ plist_data_t data_a = (plist_data_t)a;
+ plist_data_t data_b = (plist_data_t)b;
+ if (data_a->strval == NULL || data_b->strval == NULL) {
+ return FALSE;
+ }
+ if (data_a->length != data_b->length) {
+ return FALSE;
+ }
+ return (strcmp(data_a->strval, data_b->strval) == 0) ? TRUE : FALSE;
+}
+
void plist_free_data(plist_data_t data)
{
if (data)
@@ -161,6 +187,9 @@
case PLIST_DATA:
free(data->buff);
break;
+ case PLIST_DICT:
+ hash_table_destroy(data->hashtable);
+ break;
default:
break;
}
@@ -483,20 +512,27 @@
if (node && PLIST_DICT == plist_get_node_type(node))
{
-
- plist_t current = NULL;
- for (current = (plist_t)node_first_child(node);
+ plist_data_t data = plist_get_data(node);
+ hashtable_t *ht = (hashtable_t*)data->hashtable;
+ if (ht) {
+ struct plist_data_s sdata;
+ sdata.strval = (char*)key;
+ sdata.length = strlen(key);
+ ret = (plist_t)hash_table_lookup(ht, &sdata);
+ } else {
+ plist_t current = NULL;
+ for (current = (plist_t)node_first_child(node);
current;
current = (plist_t)node_next_sibling(node_next_sibling(current)))
- {
-
- plist_data_t data = plist_get_data(current);
- assert( PLIST_KEY == plist_get_node_type(current) );
-
- if (data && !strcmp(key, data->strval))
{
- ret = (plist_t)node_next_sibling(current);
- break;
+ data = plist_get_data(current);
+ assert( PLIST_KEY == plist_get_node_type(current) );
+
+ if (data && !strcmp(key, data->strval))
+ {
+ ret = (plist_t)node_next_sibling(current);
+ break;
+ }
}
}
}
@@ -507,6 +543,7 @@
{
if (node && PLIST_DICT == plist_get_node_type(node)) {
node_t* old_item = plist_dict_get_item(node, key);
+ plist_t key_node = NULL;
if (old_item) {
int idx = plist_free_node(old_item);
if (idx < 0) {
@@ -514,10 +551,32 @@
} else {
node_insert(node, idx, item);
}
+ key_node = node_prev_sibling(item);
} else {
- node_attach(node, plist_new_key(key));
+ key_node = plist_new_key(key);
+ node_attach(node, key_node);
node_attach(node, item);
}
+
+ hashtable_t *ht = ((plist_data_t)((node_t*)node)->data)->hashtable;
+ if (ht) {
+ /* store pointer to item in hash table */
+ hash_table_insert(ht, (plist_data_t)((node_t*)key_node)->data, item);
+ } else {
+ if (((node_t*)node)->count > 500) {
+ /* make new hash table */
+ ht = hash_table_new(dict_key_hash, dict_key_compare, NULL);
+ /* calculate the hashes for all entries we have so far */
+ plist_t current = NULL;
+ for (current = (plist_t)node_first_child(node);
+ ht && current;
+ current = (plist_t)node_next_sibling(node_next_sibling(current)))
+ {
+ hash_table_insert(ht, ((node_t*)current)->data, node_next_sibling(current));
+ }
+ ((plist_data_t)((node_t*)node)->data)->hashtable = ht;
+ }
+ }
}
return;
}
@@ -535,6 +594,10 @@
if (old_item)
{
plist_t key_node = node_prev_sibling(old_item);
+ hashtable_t* ht = ((plist_data_t)((node_t*)node)->data)->hashtable;
+ if (ht) {
+ hash_table_remove(ht, ((node_t*)key_node)->data);
+ }
plist_free(key_node);
plist_free(old_item);
}
diff --git a/src/plist.h b/src/plist.h
index da8f9ca..7bf62a8 100644
--- a/src/plist.h
+++ b/src/plist.h
@@ -56,6 +56,7 @@
double realval;
char *strval;
uint8_t *buff;
+ void *hashtable;
};
uint64_t length;
plist_type type;
