/* 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 Lesser 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ /* * Modified by the GLib Team and others 1997-2000. See the AUTHORS * file for a list of people on the GLib Team. See the ChangeLog * files for a list of changes. These files are distributed with * GLib at ftp://ftp.gtk.org/pub/gtk/. */ /* * MT safe */ #include "config.h" #include /* memset */ #include "ghash.h" #include "gstrfuncs.h" #include "gatomic.h" #include "gtestutils.h" #include "gslice.h" /** * SECTION:hash_tables * @title: Hash Tables * @short_description: associations between keys and values so that * given a key the value can be found quickly * * A #GHashTable provides associations between keys and values which is * optimized so that given a key, the associated value can be found * very quickly. * * Note that neither keys nor values are copied when inserted into the * #GHashTable, so they must exist for the lifetime of the #GHashTable. * This means that the use of static strings is OK, but temporary * strings (i.e. those created in buffers and those returned by GTK+ * widgets) should be copied with g_strdup() before being inserted. * * If keys or values are dynamically allocated, you must be careful to * ensure that they are freed when they are removed from the * #GHashTable, and also when they are overwritten by new insertions * into the #GHashTable. It is also not advisable to mix static strings * and dynamically-allocated strings in a #GHashTable, because it then * becomes difficult to determine whether the string should be freed. * * To create a #GHashTable, use g_hash_table_new(). * * To insert a key and value into a #GHashTable, use * g_hash_table_insert(). * * To lookup a value corresponding to a given key, use * g_hash_table_lookup() and g_hash_table_lookup_extended(). * * g_hash_table_lookup_extended() can also be used to simply * check if a key is present in the hash table. * * To remove a key and value, use g_hash_table_remove(). * * To call a function for each key and value pair use * g_hash_table_foreach() or use a iterator to iterate over the * key/value pairs in the hash table, see #GHashTableIter. * * To destroy a #GHashTable use g_hash_table_destroy(). * * * Using a GHashTable as a set * * A common use-case for hash tables is to store information about * a set of keys, without associating any particular value with each * key. GHashTable optimizes one way of doing so: If you store only * key-value pairs where key == value, then GHashTable does not * allocate memory to store the values, which can be a considerable * space saving, if your set is large. * * * GHashTable * * set_new (GHashFunc hash_func, * GEqualFunc equal_func, * GDestroyNotify destroy) * { * return g_hash_table_new_full (hash_func, equal_func, destroy, NULL); * } * * void * set_add (GHashTable *set, * gpointer element) * { * g_hash_table_replace (set, element, element); * } * * gboolean * set_contains (GHashTable *set, * gpointer element) * { * return g_hash_table_lookup_extended (set, element, NULL, NULL); * } * * gboolean * set_remove (GHashTable *set, * gpointer element) * { * return g_hash_table_remove (set, element); * } * * * * As of version 2.32, there is also a g_hash_table_add() function to * add a key to a #GHashTable that is being used as a set. */ /** * GHashTable: * * The #GHashTable struct is an opaque data structure to represent a * Hash Table. It should only be * accessed via the following functions. */ /** * GHashFunc: * @key: a key * * Specifies the type of the hash function which is passed to * g_hash_table_new() when a #GHashTable is created. * * The function is passed a key and should return a #guint hash value. * The functions g_direct_hash(), g_int_hash() and g_str_hash() provide * hash functions which can be used when the key is a #gpointer, #gint*, * and #gchar* respectively. * * g_direct_hash() is also the appropriate hash function for keys * of the form GINT_TO_POINTER (n) (or similar macros). * * A good hash functions should produce * hash values that are evenly distributed over a fairly large range. * The modulus is taken with the hash table size (a prime number) to * find the 'bucket' to place each key into. The function should also * be very fast, since it is called for each key lookup. * * Note that the hash functions provided by GLib have these qualities, * but are not particularly robust against manufactured keys that * cause hash collisions. Therefore, you should consider choosing * a more secure hash function when using a GHashTable with keys * that originate in untrusted data (such as HTTP requests). * Using g_str_hash() in that situation might make your application * vulerable to Algorithmic Complexity Attacks. * * The key to choosing a good hash is unpredictability. Even * cryptographic hashes are very easy to find collisions for when the * remainder is taken modulo a somewhat predictable prime number. There * must be an element of randomness that an attacker is unable to guess. * * Returns: the hash value corresponding to the key */ /** * GHFunc: * @key: a key * @value: the value corresponding to the key * @user_data: user data passed to g_hash_table_foreach() * * Specifies the type of the function passed to g_hash_table_foreach(). * It is called with each key/value pair, together with the @user_data * parameter which is passed to g_hash_table_foreach(). */ /** * GHRFunc: * @key: a key * @value: the value associated with the key * @user_data: user data passed to g_hash_table_remove() * * Specifies the type of the function passed to * g_hash_table_foreach_remove(). It is called with each key/value * pair, together with the @user_data parameter passed to * g_hash_table_foreach_remove(). It should return %TRUE if the * key/value pair should be removed from the #GHashTable. * * Returns: %TRUE if the key/value pair should be removed from the * #GHashTable */ /** * GEqualFunc: * @a: a value * @b: a value to compare with * * Specifies the type of a function used to test two values for * equality. The function should return %TRUE if both values are equal * and %FALSE otherwise. * * Returns: %TRUE if @a = @b; %FALSE otherwise */ /** * GHashTableIter: * * A GHashTableIter structure represents an iterator that can be used * to iterate over the elements of a #GHashTable. GHashTableIter * structures are typically allocated on the stack and then initialized * with g_hash_table_iter_init(). */ /** * g_hash_table_freeze: * @hash_table: a #GHashTable * * This function is deprecated and will be removed in the next major * release of GLib. It does nothing. */ /** * g_hash_table_thaw: * @hash_table: a #GHashTable * * This function is deprecated and will be removed in the next major * release of GLib. It does nothing. */ #define HASH_TABLE_MIN_SHIFT 3 /* 1 << 3 == 8 buckets */ #define UNUSED_HASH_VALUE 0 #define TOMBSTONE_HASH_VALUE 1 #define HASH_IS_UNUSED(h_) ((h_) == UNUSED_HASH_VALUE) #define HASH_IS_TOMBSTONE(h_) ((h_) == TOMBSTONE_HASH_VALUE) #define HASH_IS_REAL(h_) ((h_) >= 2) struct _GHashTable { gint size; gint mod; guint mask; gint nnodes; gint noccupied; /* nnodes + tombstones */ gpointer *keys; guint *hashes; gpointer *values; GHashFunc hash_func; GEqualFunc key_equal_func; gint ref_count; #ifndef G_DISABLE_ASSERT /* * Tracks the structure of the hash table, not its contents: is only * incremented when a node is added or removed (is not incremented * when the key or data of a node is modified). */ int version; #endif GDestroyNotify key_destroy_func; GDestroyNotify value_destroy_func; }; typedef struct { GHashTable *hash_table; gpointer dummy1; gpointer dummy2; int position; gboolean dummy3; int version; } RealIter; /* Each table size has an associated prime modulo (the first prime * lower than the table size) used to find the initial bucket. Probing * then works modulo 2^n. The prime modulo is necessary to get a * good distribution with poor hash functions. */ static const gint prime_mod [] = { 1, /* For 1 << 0 */ 2, 3, 7, 13, 31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, /* For 1 << 16 */ 131071, 262139, 524287, 1048573, 2097143, 4194301, 8388593, 16777213, 33554393, 67108859, 134217689, 268435399, 536870909, 1073741789, 2147483647 /* For 1 << 31 */ }; static void g_hash_table_set_shift (GHashTable *hash_table, gint shift) { gint i; guint mask = 0; hash_table->size = 1 << shift; hash_table->mod = prime_mod [shift]; for (i = 0; i < shift; i++) { mask <<= 1; mask |= 1; } hash_table->mask = mask; } static gint g_hash_table_find_closest_shift (gint n) { gint i; for (i = 0; n; i++) n >>= 1; return i; } static void g_hash_table_set_shift_from_size (GHashTable *hash_table, gint size) { gint shift; shift = g_hash_table_find_closest_shift (size); shift = MAX (shift, HASH_TABLE_MIN_SHIFT); g_hash_table_set_shift (hash_table, shift); } /* * g_hash_table_lookup_node: * @hash_table: our #GHashTable * @key: the key to lookup against * @hash_return: key hash return location * * Performs a lookup in the hash table, preserving extra information * usually needed for insertion. * * This function first computes the hash value of the key using the * user's hash function. * * If an entry in the table matching @key is found then this function * returns the index of that entry in the table, and if not, the * index of an unused node (empty or tombstone) where the key can be * inserted. * * The computed hash value is returned in the variable pointed to * by @hash_return. This is to save insertions from having to compute * the hash record again for the new record. * * Returns: index of the described node */ static inline guint g_hash_table_lookup_node (GHashTable *hash_table, gconstpointer key, guint *hash_return) { guint node_index; guint node_hash; guint hash_value; guint first_tombstone = 0; gboolean have_tombstone = FALSE; guint step = 0; hash_value = hash_table->hash_func (key); if (G_UNLIKELY (!HASH_IS_REAL (hash_value))) hash_value = 2; *hash_return = hash_value; node_index = hash_value % hash_table->mod; node_hash = hash_table->hashes[node_index]; while (!HASH_IS_UNUSED (node_hash)) { /* We first check if our full hash values * are equal so we can avoid calling the full-blown * key equality function in most cases. */ if (node_hash == hash_value) { gpointer node_key = hash_table->keys[node_index]; if (hash_table->key_equal_func) { if (hash_table->key_equal_func (node_key, key)) return node_index; } else if (node_key == key) { return node_index; } } else if (HASH_IS_TOMBSTONE (node_hash) && !have_tombstone) { first_tombstone = node_index; have_tombstone = TRUE; } step++; node_index += step; node_index &= hash_table->mask; node_hash = hash_table->hashes[node_index]; } if (have_tombstone) return first_tombstone; return node_index; } /* * g_hash_table_remove_node: * @hash_table: our #GHashTable * @node: pointer to node to remove * @notify: %TRUE if the destroy notify handlers are to be called * * Removes a node from the hash table and updates the node count. * The node is replaced by a tombstone. No table resize is performed. * * If @notify is %TRUE then the destroy notify functions are called * for the key and value of the hash node. */ static void g_hash_table_remove_node (GHashTable *hash_table, gint i, gboolean notify) { gpointer key; gpointer value; key = hash_table->keys[i]; value = hash_table->values[i]; /* Erect tombstone */ hash_table->hashes[i] = TOMBSTONE_HASH_VALUE; /* Be GC friendly */ hash_table->keys[i] = NULL; hash_table->values[i] = NULL; hash_table->nnodes--; if (notify && hash_table->key_destroy_func) hash_table->key_destroy_func (key); if (notify && hash_table->value_destroy_func) hash_table->value_destroy_func (value); } /* * g_hash_table_remove_all_nodes: * @hash_table: our #GHashTable * @notify: %TRUE if the destroy notify handlers are to be called * * Removes all nodes from the table. Since this may be a precursor to * freeing the table entirely, no resize is performed. * * If @notify is %TRUE then the destroy notify functions are called * for the key and value of the hash node. */ static void g_hash_table_remove_all_nodes (GHashTable *hash_table, gboolean notify) { int i; gpointer key; gpointer value; hash_table->nnodes = 0; hash_table->noccupied = 0; if (!notify || (hash_table->key_destroy_func == NULL && hash_table->value_destroy_func == NULL)) { memset (hash_table->hashes, 0, hash_table->size * sizeof (guint)); memset (hash_table->keys, 0, hash_table->size * sizeof (gpointer)); memset (hash_table->values, 0, hash_table->size * sizeof (gpointer)); return; } for (i = 0; i < hash_table->size; i++) { if (HASH_IS_REAL (hash_table->hashes[i])) { key = hash_table->keys[i]; value = hash_table->values[i]; hash_table->hashes[i] = UNUSED_HASH_VALUE; hash_table->keys[i] = NULL; hash_table->values[i] = NULL; if (hash_table->key_destroy_func != NULL) hash_table->key_destroy_func (key); if (hash_table->value_destroy_func != NULL) hash_table->value_destroy_func (value); } else if (HASH_IS_TOMBSTONE (hash_table->hashes[i])) { hash_table->hashes[i] = UNUSED_HASH_VALUE; } } } /* * g_hash_table_resize: * @hash_table: our #GHashTable * * Resizes the hash table to the optimal size based on the number of * nodes currently held. If you call this function then a resize will * occur, even if one does not need to occur. * Use g_hash_table_maybe_resize() instead. * * This function may "resize" the hash table to its current size, with * the side effect of cleaning up tombstones and otherwise optimizing * the probe sequences. */ static void g_hash_table_resize (GHashTable *hash_table) { gpointer *new_keys; gpointer *new_values; guint *new_hashes; gint old_size; gint i; old_size = hash_table->size; g_hash_table_set_shift_from_size (hash_table, hash_table->nnodes * 2); new_keys = g_new0 (gpointer, hash_table->size); if (hash_table->keys == hash_table->values) new_values = new_keys; else new_values = g_new0 (gpointer, hash_table->size); new_hashes = g_new0 (guint, hash_table->size); for (i = 0; i < old_size; i++) { guint node_hash = hash_table->hashes[i]; guint hash_val; guint step = 0; if (!HASH_IS_REAL (node_hash)) continue; hash_val = node_hash % hash_table->mod; while (!HASH_IS_UNUSED (new_hashes[hash_val])) { step++; hash_val += step; hash_val &= hash_table->mask; } new_hashes[hash_val] = hash_table->hashes[i]; new_keys[hash_val] = hash_table->keys[i]; new_values[hash_val] = hash_table->values[i]; } if (hash_table->keys != hash_table->values) g_free (hash_table->values); g_free (hash_table->keys); g_free (hash_table->hashes); hash_table->keys = new_keys; hash_table->values = new_values; hash_table->hashes = new_hashes; hash_table->noccupied = hash_table->nnodes; } /* * g_hash_table_maybe_resize: * @hash_table: our #GHashTable * * Resizes the hash table, if needed. * * Essentially, calls g_hash_table_resize() if the table has strayed * too far from its ideal size for its number of nodes. */ static inline void g_hash_table_maybe_resize (GHashTable *hash_table) { gint noccupied = hash_table->noccupied; gint size = hash_table->size; if ((size > hash_table->nnodes * 4 && size > 1 << HASH_TABLE_MIN_SHIFT) || (size <= noccupied + (noccupied / 16))) g_hash_table_resize (hash_table); } /** * g_hash_table_new: * @hash_func: a function to create a hash value from a key * @key_equal_func: a function to check two keys for equality * * Creates a new #GHashTable with a reference count of 1. * * Hash values returned by @hash_func are used to determine where keys * are stored within the #GHashTable data structure. The g_direct_hash(), * g_int_hash(), g_int64_hash(), g_double_hash() and g_str_hash() * functions are provided for some common types of keys. * If @hash_func is %NULL, g_direct_hash() is used. * * @key_equal_func is used when looking up keys in the #GHashTable. * The g_direct_equal(), g_int_equal(), g_int64_equal(), g_double_equal() * and g_str_equal() functions are provided for the most common types * of keys. If @key_equal_func is %NULL, keys are compared directly in * a similar fashion to g_direct_equal(), but without the overhead of * a function call. * * Return value: a new #GHashTable */ GHashTable * g_hash_table_new (GHashFunc hash_func, GEqualFunc key_equal_func) { return g_hash_table_new_full (hash_func, key_equal_func, NULL, NULL); } /** * g_hash_table_new_full: * @hash_func: a function to create a hash value from a key * @key_equal_func: a function to check two keys for equality * @key_destroy_func: (allow-none): a function to free the memory allocated for the key * used when removing the entry from the #GHashTable, or %NULL * if you don't want to supply such a function. * @value_destroy_func: (allow-none): a function to free the memory allocated for the * value used when removing the entry from the #GHashTable, or %NULL * if you don't want to supply such a function. * * Creates a new #GHashTable like g_hash_table_new() with a reference * count of 1 and allows to specify functions to free the memory * allocated for the key and value that get called when removing the * entry from the #GHashTable. * * Return value: a new #GHashTable */ GHashTable * g_hash_table_new_full (GHashFunc hash_func, GEqualFunc key_equal_func, GDestroyNotify key_destroy_func, GDestroyNotify value_destroy_func) { GHashTable *hash_table; hash_table = g_slice_new (GHashTable); g_hash_table_set_shift (hash_table, HASH_TABLE_MIN_SHIFT); hash_table->nnodes = 0; hash_table->noccupied = 0; hash_table->hash_func = hash_func ? hash_func : g_direct_hash; hash_table->key_equal_func = key_equal_func; hash_table->ref_count = 1; #ifndef G_DISABLE_ASSERT hash_table->version = 0; #endif hash_table->key_destroy_func = key_destroy_func; hash_table->value_destroy_func = value_destroy_func; hash_table->keys = g_new0 (gpointer, hash_table->size); hash_table->values = hash_table->keys; hash_table->hashes = g_new0 (guint, hash_table->size); return hash_table; } /** * g_hash_table_iter_init: * @iter: an uninitialized #GHashTableIter * @hash_table: a #GHashTable * * Initializes a key/value pair iterator and associates it with * @hash_table. Modifying the hash table after calling this function * invalidates the returned iterator. * |[ * GHashTableIter iter; * gpointer key, value; * * g_hash_table_iter_init (&iter, hash_table); * while (g_hash_table_iter_next (&iter, &key, &value)) * { * /* do something with key and value */ * } * ]| * * Since: 2.16 */ void g_hash_table_iter_init (GHashTableIter *iter, GHashTable *hash_table) { RealIter *ri = (RealIter *) iter; g_return_if_fail (iter != NULL); g_return_if_fail (hash_table != NULL); ri->hash_table = hash_table; ri->position = -1; #ifndef G_DISABLE_ASSERT ri->version = hash_table->version; #endif } /** * g_hash_table_iter_next: * @iter: an initialized #GHashTableIter * @key: (allow-none): a location to store the key, or %NULL * @value: (allow-none): a location to store the value, or %NULL * * Advances @iter and retrieves the key and/or value that are now * pointed to as a result of this advancement. If %FALSE is returned, * @key and @value are not set, and the iterator becomes invalid. * * Return value: %FALSE if the end of the #GHashTable has been reached. * * Since: 2.16 */ gboolean g_hash_table_iter_next (GHashTableIter *iter, gpointer *key, gpointer *value) { RealIter *ri = (RealIter *) iter; gint position; g_return_val_if_fail (iter != NULL, FALSE); #ifndef G_DISABLE_ASSERT g_return_val_if_fail (ri->version == ri->hash_table->version, FALSE); #endif g_return_val_if_fail (ri->position < ri->hash_table->size, FALSE); position = ri->position; do { position++; if (position >= ri->hash_table->size) { ri->position = position; return FALSE; } } while (!HASH_IS_REAL (ri->hash_table->hashes[position])); if (key != NULL) *key = ri->hash_table->keys[position]; if (value != NULL) *value = ri->hash_table->values[position]; ri->position = position; return TRUE; } /** * g_hash_table_iter_get_hash_table: * @iter: an initialized #GHashTableIter * * Returns the #GHashTable associated with @iter. * * Return value: the #GHashTable associated with @iter. * * Since: 2.16 */ GHashTable * g_hash_table_iter_get_hash_table (GHashTableIter *iter) { g_return_val_if_fail (iter != NULL, NULL); return ((RealIter *) iter)->hash_table; } static void iter_remove_or_steal (RealIter *ri, gboolean notify) { g_return_if_fail (ri != NULL); #ifndef G_DISABLE_ASSERT g_return_if_fail (ri->version == ri->hash_table->version); #endif g_return_if_fail (ri->position >= 0); g_return_if_fail (ri->position < ri->hash_table->size); g_hash_table_remove_node (ri->hash_table, ri->position, notify); #ifndef G_DISABLE_ASSERT ri->version++; ri->hash_table->version++; #endif } /** * g_hash_table_iter_remove: * @iter: an initialized #GHashTableIter * * Removes the key/value pair currently pointed to by the iterator * from its associated #GHashTable. Can only be called after * g_hash_table_iter_next() returned %TRUE, and cannot be called * more than once for the same key/value pair. * * If the #GHashTable was created using g_hash_table_new_full(), * the key and value are freed using the supplied destroy functions, * otherwise you have to make sure that any dynamically allocated * values are freed yourself. * * Since: 2.16 */ void g_hash_table_iter_remove (GHashTableIter *iter) { iter_remove_or_steal ((RealIter *) iter, TRUE); } /* * g_hash_table_insert_node: * @hash_table: our #GHashTable * @node_index: pointer to node to insert/replace * @key_hash: key hash * @key: (allow-none): key to replace with, or %NULL * @value: value to replace with * @keep_new_key: whether to replace the key in the node with @key * @reusing_key: whether @key was taken out of the existing node * * Inserts a value at @node_index in the hash table and updates it. * * If @key has been taken out of the existing node (ie it is not * passed in via a g_hash_table_insert/replace) call, then @reusing_key * should be %TRUE. */ static void g_hash_table_insert_node (GHashTable *hash_table, guint node_index, guint key_hash, gpointer key, gpointer value, gboolean keep_new_key, gboolean reusing_key) { guint old_hash; gpointer old_key; gpointer old_value; if (G_UNLIKELY (hash_table->keys == hash_table->values && key != value)) hash_table->values = g_memdup (hash_table->keys, sizeof (gpointer) * hash_table->size); old_hash = hash_table->hashes[node_index]; old_key = hash_table->keys[node_index]; old_value = hash_table->values[node_index]; if (HASH_IS_REAL (old_hash)) { if (keep_new_key) hash_table->keys[node_index] = key; hash_table->values[node_index] = value; } else { hash_table->keys[node_index] = key; hash_table->values[node_index] = value; hash_table->hashes[node_index] = key_hash; hash_table->nnodes++; if (HASH_IS_UNUSED (old_hash)) { /* We replaced an empty node, and not a tombstone */ hash_table->noccupied++; g_hash_table_maybe_resize (hash_table); } #ifndef G_DISABLE_ASSERT hash_table->version++; #endif } if (HASH_IS_REAL (old_hash)) { if (hash_table->key_destroy_func && !reusing_key) hash_table->key_destroy_func (keep_new_key ? old_key : key); if (hash_table->value_destroy_func) hash_table->value_destroy_func (old_value); } } /** * g_hash_table_iter_replace: * @iter: an initialized #GHashTableIter * @value: the value to replace with * * Replaces the value currently pointed to by the iterator * from its associated #GHashTable. Can only be called after * g_hash_table_iter_next() returned %TRUE. * * If you supplied a @value_destroy_func when creating the * #GHashTable, the old value is freed using that function. * * Since: 2.30 */ void g_hash_table_iter_replace (GHashTableIter *iter, gpointer value) { RealIter *ri; guint node_hash; gpointer key; ri = (RealIter *) iter; g_return_if_fail (ri != NULL); #ifndef G_DISABLE_ASSERT g_return_if_fail (ri->version == ri->hash_table->version); #endif g_return_if_fail (ri->position >= 0); g_return_if_fail (ri->position < ri->hash_table->size); node_hash = ri->hash_table->hashes[ri->position]; key = ri->hash_table->keys[ri->position]; g_hash_table_insert_node (ri->hash_table, ri->position, node_hash, key, value, TRUE, TRUE); #ifndef G_DISABLE_ASSERT ri->version++; ri->hash_table->version++; #endif } /** * g_hash_table_iter_steal: * @iter: an initialized #GHashTableIter * * Removes the key/value pair currently pointed to by the * iterator from its associated #GHashTable, without calling * the key and value destroy functions. Can only be called * after g_hash_table_iter_next() returned %TRUE, and cannot * be called more than once for the same key/value pair. * * Since: 2.16 */ void g_hash_table_iter_steal (GHashTableIter *iter) { iter_remove_or_steal ((RealIter *) iter, FALSE); } /** * g_hash_table_ref: * @hash_table: a valid #GHashTable * * Atomically increments the reference count of @hash_table by one. * This function is MT-safe and may be called from any thread. * * Return value: the passed in #GHashTable * * Since: 2.10 */ GHashTable * g_hash_table_ref (GHashTable *hash_table) { g_return_val_if_fail (hash_table != NULL, NULL); g_atomic_int_inc (&hash_table->ref_count); return hash_table; } /** * g_hash_table_unref: * @hash_table: a valid #GHashTable * * Atomically decrements the reference count of @hash_table by one. * If the reference count drops to 0, all keys and values will be * destroyed, and all memory allocated by the hash table is released. * This function is MT-safe and may be called from any thread. * * Since: 2.10 */ void g_hash_table_unref (GHashTable *hash_table) { g_return_if_fail (hash_table != NULL); if (g_atomic_int_dec_and_test (&hash_table->ref_count)) { g_hash_table_remove_all_nodes (hash_table, TRUE); if (hash_table->keys != hash_table->values) g_free (hash_table->values); g_free (hash_table->keys); g_free (hash_table->hashes); g_slice_free (GHashTable, hash_table); } } /** * g_hash_table_destroy: * @hash_table: a #GHashTable * * Destroys all keys and values in the #GHashTable and decrements its * reference count by 1. If keys and/or values are dynamically allocated, * you should either free them first or create the #GHashTable with destroy * notifiers using g_hash_table_new_full(). In the latter case the destroy * functions you supplied will be called on all keys and values during the * destruction phase. */ void g_hash_table_destroy (GHashTable *hash_table) { g_return_if_fail (hash_table != NULL); g_hash_table_remove_all (hash_table); g_hash_table_unref (hash_table); } /** * g_hash_table_lookup: * @hash_table: a #GHashTable * @key: the key to look up * * Looks up a key in a #GHashTable. Note that this function cannot * distinguish between a key that is not present and one which is present * and has the value %NULL. If you need this distinction, use * g_hash_table_lookup_extended(). * * Return value: (allow-none): the associated value, or %NULL if the key is not found */ gpointer g_hash_table_lookup (GHashTable *hash_table, gconstpointer key) { guint node_index; guint node_hash; g_return_val_if_fail (hash_table != NULL, NULL); node_index = g_hash_table_lookup_node (hash_table, key, &node_hash); return HASH_IS_REAL (hash_table->hashes[node_index]) ? hash_table->values[node_index] : NULL; } /** * g_hash_table_lookup_extended: * @hash_table: a #GHashTable * @lookup_key: the key to look up * @orig_key: (allow-none): return location for the original key, or %NULL * @value: (allow-none): return location for the value associated with the key, or %NULL * * Looks up a key in the #GHashTable, returning the original key and the * associated value and a #gboolean which is %TRUE if the key was found. This * is useful if you need to free the memory allocated for the original key, * for example before calling g_hash_table_remove(). * * You can actually pass %NULL for @lookup_key to test * whether the %NULL key exists, provided the hash and equal functions * of @hash_table are %NULL-safe. * * Return value: %TRUE if the key was found in the #GHashTable */ gboolean g_hash_table_lookup_extended (GHashTable *hash_table, gconstpointer lookup_key, gpointer *orig_key, gpointer *value) { guint node_index; guint node_hash; g_return_val_if_fail (hash_table != NULL, FALSE); node_index = g_hash_table_lookup_node (hash_table, lookup_key, &node_hash); if (!HASH_IS_REAL (hash_table->hashes[node_index])) return FALSE; if (orig_key) *orig_key = hash_table->keys[node_index]; if (value) *value = hash_table->values[node_index]; return TRUE; } /* * g_hash_table_insert_internal: * @hash_table: our #GHashTable * @key: the key to insert * @value: the value to insert * @keep_new_key: if %TRUE and this key already exists in the table * then call the destroy notify function on the old key. If %FALSE * then call the destroy notify function on the new key. * * Implements the common logic for the g_hash_table_insert() and * g_hash_table_replace() functions. * * Do a lookup of @key. If it is found, replace it with the new * @value (and perhaps the new @key). If it is not found, create * a new node. */ static void g_hash_table_insert_internal (GHashTable *hash_table, gpointer key, gpointer value, gboolean keep_new_key) { guint key_hash; guint node_index; g_return_if_fail (hash_table != NULL); node_index = g_hash_table_lookup_node (hash_table, key, &key_hash); g_hash_table_insert_node (hash_table, node_index, key_hash, key, value, keep_new_key, FALSE); } /** * g_hash_table_insert: * @hash_table: a #GHashTable * @key: a key to insert * @value: the value to associate with the key * * Inserts a new key and value into a #GHashTable. * * If the key already exists in the #GHashTable its current * value is replaced with the new value. If you supplied a * @value_destroy_func when creating the #GHashTable, the old * value is freed using that function. If you supplied a * @key_destroy_func when creating the #GHashTable, the passed * key is freed using that function. */ void g_hash_table_insert (GHashTable *hash_table, gpointer key, gpointer value) { g_hash_table_insert_internal (hash_table, key, value, FALSE); } /** * g_hash_table_replace: * @hash_table: a #GHashTable * @key: a key to insert * @value: the value to associate with the key * * Inserts a new key and value into a #GHashTable similar to * g_hash_table_insert(). The difference is that if the key * already exists in the #GHashTable, it gets replaced by the * new key. If you supplied a @value_destroy_func when creating * the #GHashTable, the old value is freed using that function. * If you supplied a @key_destroy_func when creating the * #GHashTable, the old key is freed using that function. */ void g_hash_table_replace (GHashTable *hash_table, gpointer key, gpointer value) { g_hash_table_insert_internal (hash_table, key, value, TRUE); } /** * g_hash_table_add: * @hash_table: a #GHashTable * @key: a key to insert * * This is a convenience function for using a #GHashTable as a set. It * is equivalent to calling g_hash_table_replace() with @key as both the * key and the value. * * When a hash table only ever contains keys that have themselves as the * corresponding value it is able to be stored more efficiently. See * the discussion in the section description. * * Since: 2.32 **/ void g_hash_table_add (GHashTable *hash_table, gpointer key) { g_hash_table_insert_internal (hash_table, key, key, TRUE); } /** * g_hash_table_contains: * @hash_table: a #GHashTable * @key: a key to check * * Checks if @key is in @hash_table. * * Since: 2.32 **/ gboolean g_hash_table_contains (GHashTable *hash_table, gconstpointer key) { guint node_index; guint node_hash; g_return_val_if_fail (hash_table != NULL, FALSE); node_index = g_hash_table_lookup_node (hash_table, key, &node_hash); return HASH_IS_REAL (hash_table->hashes[node_index]); } /* * g_hash_table_remove_internal: * @hash_table: our #GHashTable * @key: the key to remove * @notify: %TRUE if the destroy notify handlers are to be called * Return value: %TRUE if a node was found and removed, else %FALSE * * Implements the common logic for the g_hash_table_remove() and * g_hash_table_steal() functions. * * Do a lookup of @key and remove it if it is found, calling the * destroy notify handlers only if @notify is %TRUE. */ static gboolean g_hash_table_remove_internal (GHashTable *hash_table, gconstpointer key, gboolean notify) { guint node_index; guint node_hash; g_return_val_if_fail (hash_table != NULL, FALSE); node_index = g_hash_table_lookup_node (hash_table, key, &node_hash); if (!HASH_IS_REAL (hash_table->hashes[node_index])) return FALSE; g_hash_table_remove_node (hash_table, node_index, notify); g_hash_table_maybe_resize (hash_table); #ifndef G_DISABLE_ASSERT hash_table->version++; #endif return TRUE; } /** * g_hash_table_remove: * @hash_table: a #GHashTable * @key: the key to remove * * Removes a key and its associated value from a #GHashTable. * * If the #GHashTable was created using g_hash_table_new_full(), the * key and value are freed using the supplied destroy functions, otherwise * you have to make sure that any dynamically allocated values are freed * yourself. * * Returns: %TRUE if the key was found and removed from the #GHashTable */ gboolean g_hash_table_remove (GHashTable *hash_table, gconstpointer key) { return g_hash_table_remove_internal (hash_table, key, TRUE); } /** * g_hash_table_steal: * @hash_table: a #GHashTable * @key: the key to remove * * Removes a key and its associated value from a #GHashTable without * calling the key and value destroy functions. * * Returns: %TRUE if the key was found and removed from the #GHashTable */ gboolean g_hash_table_steal (GHashTable *hash_table, gconstpointer key) { return g_hash_table_remove_internal (hash_table, key, FALSE); } /** * g_hash_table_remove_all: * @hash_table: a #GHashTable * * Removes all keys and their associated values from a #GHashTable. * * If the #GHashTable was created using g_hash_table_new_full(), * the keys and values are freed using the supplied destroy functions, * otherwise you have to make sure that any dynamically allocated * values are freed yourself. * * Since: 2.12 */ void g_hash_table_remove_all (GHashTable *hash_table) { g_return_if_fail (hash_table != NULL); #ifndef G_DISABLE_ASSERT if (hash_table->nnodes != 0) hash_table->version++; #endif g_hash_table_remove_all_nodes (hash_table, TRUE); g_hash_table_maybe_resize (hash_table); } /** * g_hash_table_steal_all: * @hash_table: a #GHashTable * * Removes all keys and their associated values from a #GHashTable * without calling the key and value destroy functions. * * Since: 2.12 */ void g_hash_table_steal_all (GHashTable *hash_table) { g_return_if_fail (hash_table != NULL); #ifndef G_DISABLE_ASSERT if (hash_table->nnodes != 0) hash_table->version++; #endif g_hash_table_remove_all_nodes (hash_table, FALSE); g_hash_table_maybe_resize (hash_table); } /* * g_hash_table_foreach_remove_or_steal: * @hash_table: a #GHashTable * @func: the user's callback function * @user_data: data for @func * @notify: %TRUE if the destroy notify handlers are to be called * * Implements the common logic for g_hash_table_foreach_remove() * and g_hash_table_foreach_steal(). * * Iterates over every node in the table, calling @func with the key * and value of the node (and @user_data). If @func returns %TRUE the * node is removed from the table. * * If @notify is true then the destroy notify handlers will be called * for each removed node. */ static guint g_hash_table_foreach_remove_or_steal (GHashTable *hash_table, GHRFunc func, gpointer user_data, gboolean notify) { guint deleted = 0; gint i; #ifndef G_DISABLE_ASSERT gint version = hash_table->version; #endif for (i = 0; i < hash_table->size; i++) { guint node_hash = hash_table->hashes[i]; gpointer node_key = hash_table->keys[i]; gpointer node_value = hash_table->values[i]; if (HASH_IS_REAL (node_hash) && (* func) (node_key, node_value, user_data)) { g_hash_table_remove_node (hash_table, i, notify); deleted++; } #ifndef G_DISABLE_ASSERT g_return_val_if_fail (version == hash_table->version, 0); #endif } g_hash_table_maybe_resize (hash_table); #ifndef G_DISABLE_ASSERT if (deleted > 0) hash_table->version++; #endif return deleted; } /** * g_hash_table_foreach_remove: * @hash_table: a #GHashTable * @func: the function to call for each key/value pair * @user_data: user data to pass to the function * * Calls the given function for each key/value pair in the * #GHashTable. If the function returns %TRUE, then the key/value * pair is removed from the #GHashTable. If you supplied key or * value destroy functions when creating the #GHashTable, they are * used to free the memory allocated for the removed keys and values. * * See #GHashTableIter for an alternative way to loop over the * key/value pairs in the hash table. * * Return value: the number of key/value pairs removed */ guint g_hash_table_foreach_remove (GHashTable *hash_table, GHRFunc func, gpointer user_data) { g_return_val_if_fail (hash_table != NULL, 0); g_return_val_if_fail (func != NULL, 0); return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, TRUE); } /** * g_hash_table_foreach_steal: * @hash_table: a #GHashTable * @func: the function to call for each key/value pair * @user_data: user data to pass to the function * * Calls the given function for each key/value pair in the * #GHashTable. If the function returns %TRUE, then the key/value * pair is removed from the #GHashTable, but no key or value * destroy functions are called. * * See #GHashTableIter for an alternative way to loop over the * key/value pairs in the hash table. * * Return value: the number of key/value pairs removed. */ guint g_hash_table_foreach_steal (GHashTable *hash_table, GHRFunc func, gpointer user_data) { g_return_val_if_fail (hash_table != NULL, 0); g_return_val_if_fail (func != NULL, 0); return g_hash_table_foreach_remove_or_steal (hash_table, func, user_data, FALSE); } /** * g_hash_table_foreach: * @hash_table: a #GHashTable * @func: the function to call for each key/value pair * @user_data: user data to pass to the function * * Calls the given function for each of the key/value pairs in the * #GHashTable. The function is passed the key and value of each * pair, and the given @user_data parameter. The hash table may not * be modified while iterating over it (you can't add/remove * items). To remove all items matching a predicate, use * g_hash_table_foreach_remove(). * * See g_hash_table_find() for performance caveats for linear * order searches in contrast to g_hash_table_lookup(). */ void g_hash_table_foreach (GHashTable *hash_table, GHFunc func, gpointer user_data) { gint i; #ifndef G_DISABLE_ASSERT gint version; #endif g_return_if_fail (hash_table != NULL); g_return_if_fail (func != NULL); #ifndef G_DISABLE_ASSERT version = hash_table->version; #endif for (i = 0; i < hash_table->size; i++) { guint node_hash = hash_table->hashes[i]; gpointer node_key = hash_table->keys[i]; gpointer node_value = hash_table->values[i]; if (HASH_IS_REAL (node_hash)) (* func) (node_key, node_value, user_data); #ifndef G_DISABLE_ASSERT g_return_if_fail (version == hash_table->version); #endif } } /** * g_hash_table_find: * @hash_table: a #GHashTable * @predicate: function to test the key/value pairs for a certain property * @user_data: user data to pass to the function * * Calls the given function for key/value pairs in the #GHashTable * until @predicate returns %TRUE. The function is passed the key * and value of each pair, and the given @user_data parameter. The * hash table may not be modified while iterating over it (you can't * add/remove items). * * Note, that hash tables are really only optimized for forward * lookups, i.e. g_hash_table_lookup(). So code that frequently issues * g_hash_table_find() or g_hash_table_foreach() (e.g. in the order of * once per every entry in a hash table) should probably be reworked * to use additional or different data structures for reverse lookups * (keep in mind that an O(n) find/foreach operation issued for all n * values in a hash table ends up needing O(n*n) operations). * * Return value: (allow-none): The value of the first key/value pair is returned, * for which @predicate evaluates to %TRUE. If no pair with the * requested property is found, %NULL is returned. * * Since: 2.4 */ gpointer g_hash_table_find (GHashTable *hash_table, GHRFunc predicate, gpointer user_data) { gint i; #ifndef G_DISABLE_ASSERT gint version; #endif gboolean match; g_return_val_if_fail (hash_table != NULL, NULL); g_return_val_if_fail (predicate != NULL, NULL); #ifndef G_DISABLE_ASSERT version = hash_table->version; #endif match = FALSE; for (i = 0; i < hash_table->size; i++) { guint node_hash = hash_table->hashes[i]; gpointer node_key = hash_table->keys[i]; gpointer node_value = hash_table->values[i]; if (HASH_IS_REAL (node_hash)) match = predicate (node_key, node_value, user_data); #ifndef G_DISABLE_ASSERT g_return_val_if_fail (version == hash_table->version, NULL); #endif if (match) return node_value; } return NULL; } /** * g_hash_table_size: * @hash_table: a #GHashTable * * Returns the number of elements contained in the #GHashTable. * * Return value: the number of key/value pairs in the #GHashTable. */ guint g_hash_table_size (GHashTable *hash_table) { g_return_val_if_fail (hash_table != NULL, 0); return hash_table->nnodes; } /** * g_hash_table_get_keys: * @hash_table: a #GHashTable * * Retrieves every key inside @hash_table. The returned data * is valid until @hash_table is modified. * * Return value: a #GList containing all the keys inside the hash * table. The content of the list is owned by the hash table and * should not be modified or freed. Use g_list_free() when done * using the list. * * Since: 2.14 */ GList * g_hash_table_get_keys (GHashTable *hash_table) { gint i; GList *retval; g_return_val_if_fail (hash_table != NULL, NULL); retval = NULL; for (i = 0; i < hash_table->size; i++) { if (HASH_IS_REAL (hash_table->hashes[i])) retval = g_list_prepend (retval, hash_table->keys[i]); } return retval; } /** * g_hash_table_get_values: * @hash_table: a #GHashTable * * Retrieves every value inside @hash_table. The returned data * is valid until @hash_table is modified. * * Return value: a #GList containing all the values inside the hash * table. The content of the list is owned by the hash table and * should not be modified or freed. Use g_list_free() when done * using the list. * * Since: 2.14 */ GList * g_hash_table_get_values (GHashTable *hash_table) { gint i; GList *retval; g_return_val_if_fail (hash_table != NULL, NULL); retval = NULL; for (i = 0; i < hash_table->size; i++) { if (HASH_IS_REAL (hash_table->hashes[i])) retval = g_list_prepend (retval, hash_table->values[i]); } return retval; } /* Hash functions. */ /** * g_str_equal: * @v1: a key * @v2: a key to compare with @v1 * * Compares two strings for byte-by-byte equality and returns %TRUE * if they are equal. It can be passed to g_hash_table_new() as the * @key_equal_func parameter, when using non-%NULL strings as keys in a * #GHashTable. * * Note that this function is primarily meant as a hash table comparison * function. For a general-purpose, %NULL-safe string comparison function, * see g_strcmp0(). * * Returns: %TRUE if the two keys match */ gboolean g_str_equal (gconstpointer v1, gconstpointer v2) { const gchar *string1 = v1; const gchar *string2 = v2; return strcmp (string1, string2) == 0; } /** * g_str_hash: * @v: a string key * * Converts a string to a hash value. * * This function implements the widely used "djb" hash apparently posted * by Daniel Bernstein to comp.lang.c some time ago. The 32 bit * unsigned hash value starts at 5381 and for each byte 'c' in the * string, is updated: hash = hash * 33 + c. This * function uses the signed value of each byte. * * It can be passed to g_hash_table_new() as the @hash_func parameter, * when using non-%NULL strings as keys in a #GHashTable. * * Returns: a hash value corresponding to the key */ guint g_str_hash (gconstpointer v) { const signed char *p; guint32 h = 5381; for (p = v; *p != '\0'; p++) h = (h << 5) + h + *p; return h; } /** * g_direct_hash: * @v: (allow-none): a #gpointer key * * Converts a gpointer to a hash value. * It can be passed to g_hash_table_new() as the @hash_func parameter, * when using opaque pointers compared by pointer value as keys in a * #GHashTable. * * This hash function is also appropriate for keys that are integers stored * in pointers, such as GINT_TO_POINTER (n). * * Returns: a hash value corresponding to the key. */ guint g_direct_hash (gconstpointer v) { return GPOINTER_TO_UINT (v); } /** * g_direct_equal: * @v1: (allow-none): a key * @v2: (allow-none): a key to compare with @v1 * * Compares two #gpointer arguments and returns %TRUE if they are equal. * It can be passed to g_hash_table_new() as the @key_equal_func * parameter, when using opaque pointers compared by pointer value as keys * in a #GHashTable. * * This equality function is also appropriate for keys that are integers stored * in pointers, such as GINT_TO_POINTER (n). * * Returns: %TRUE if the two keys match. */ gboolean g_direct_equal (gconstpointer v1, gconstpointer v2) { return v1 == v2; } /** * g_int_equal: * @v1: a pointer to a #gint key * @v2: a pointer to a #gint key to compare with @v1 * * Compares the two #gint values being pointed to and returns * %TRUE if they are equal. * It can be passed to g_hash_table_new() as the @key_equal_func * parameter, when using non-%NULL pointers to integers as keys in a * #GHashTable. * * Note that this function acts on pointers to #gint, not on #gint directly: * if your hash table's keys are of the form * GINT_TO_POINTER (n), use g_direct_equal() instead. * * Returns: %TRUE if the two keys match. */ gboolean g_int_equal (gconstpointer v1, gconstpointer v2) { return *((const gint*) v1) == *((const gint*) v2); } /** * g_int_hash: * @v: a pointer to a #gint key * * Converts a pointer to a #gint to a hash value. * It can be passed to g_hash_table_new() as the @hash_func parameter, * when using non-%NULL pointers to integer values as keys in a #GHashTable. * * Note that this function acts on pointers to #gint, not on #gint directly: * if your hash table's keys are of the form * GINT_TO_POINTER (n), use g_direct_hash() instead. * * Returns: a hash value corresponding to the key. */ guint g_int_hash (gconstpointer v) { return *(const gint*) v; } /** * g_int64_equal: * @v1: a pointer to a #gint64 key * @v2: a pointer to a #gint64 key to compare with @v1 * * Compares the two #gint64 values being pointed to and returns * %TRUE if they are equal. * It can be passed to g_hash_table_new() as the @key_equal_func * parameter, when using non-%NULL pointers to 64-bit integers as keys in a * #GHashTable. * * Returns: %TRUE if the two keys match. * * Since: 2.22 */ gboolean g_int64_equal (gconstpointer v1, gconstpointer v2) { return *((const gint64*) v1) == *((const gint64*) v2); } /** * g_int64_hash: * @v: a pointer to a #gint64 key * * Converts a pointer to a #gint64 to a hash value. * * It can be passed to g_hash_table_new() as the @hash_func parameter, * when using non-%NULL pointers to 64-bit integer values as keys in a * #GHashTable. * * Returns: a hash value corresponding to the key. * * Since: 2.22 */ guint g_int64_hash (gconstpointer v) { return (guint) *(const gint64*) v; } /** * g_double_equal: * @v1: a pointer to a #gdouble key * @v2: a pointer to a #gdouble key to compare with @v1 * * Compares the two #gdouble values being pointed to and returns * %TRUE if they are equal. * It can be passed to g_hash_table_new() as the @key_equal_func * parameter, when using non-%NULL pointers to doubles as keys in a * #GHashTable. * * Returns: %TRUE if the two keys match. * * Since: 2.22 */ gboolean g_double_equal (gconstpointer v1, gconstpointer v2) { return *((const gdouble*) v1) == *((const gdouble*) v2); } /** * g_double_hash: * @v: a pointer to a #gdouble key * * Converts a pointer to a #gdouble to a hash value. * It can be passed to g_hash_table_new() as the @hash_func parameter, * It can be passed to g_hash_table_new() as the @hash_func parameter, * when using non-%NULL pointers to doubles as keys in a #GHashTable. * * Returns: a hash value corresponding to the key. * * Since: 2.22 */ guint g_double_hash (gconstpointer v) { return (guint) *(const gdouble*) v; }