luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2024-11-10 11:26:16 +01:00
Code Issues Packages Projects Releases Wiki Activity
6f327315dc
glib/glib/ghash.c
Ryan Lortie 2e53e50244 glib/: fully remove galias hacks
2010-07-07 19:34:35 -04:00

1458 lines
40 KiB
C
Raw Blame History

/* 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 <string.h> /* memset */
#include "glib.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().
*
* 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().
**/
/**
* GHashTable:
*
* The #GHashTable struct is an opaque data structure to represent a
* <link linkend="glib-Hash-Tables">Hash Table</link>. It should only be
* accessed via the following functions.
**/
/**
* GHashFunc:
* @key: a key.
* @Returns: the hash value corresponding to the 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.
*
* <!-- FIXME: Need more here. --> The hash values should be 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.
**/
/**
* 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().
* @Returns: %TRUE if the key/value pair should be removed from the
* #GHashTable.
*
* 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.
**/
/**
* GEqualFunc:
* @a: a value.
* @b: a value to compare with.
* @Returns: %TRUE if @a = @b; %FALSE otherwise.
*
* 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.
**/
/**
* 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().
**/
#define HASH_TABLE_MIN_SHIFT 3 /* 1 << 3 == 8 buckets */
typedef struct _GHashNode GHashNode;
struct _GHashNode
{
gpointer key;
gpointer value;
/* If key_hash == 0, node is not in use
* If key_hash == 1, node is a tombstone
* If key_hash >= 2, node contains data */
guint key_hash;
};
struct _GHashTable
{
gint size;
gint mod;
guint mask;
gint nnodes;
gint noccupied; /* nnodes + tombstones */
GHashNode *nodes;
GHashFunc hash_func;
GEqualFunc key_equal_func;
volatile 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: optional key hash return location
* Return value: index of the described #GHashNode
*
* Performs a lookup in the hash table. Virtually all hash operations
* will use this function internally.
*
* 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 empty node (never a tombstone).
*/
static inline guint
g_hash_table_lookup_node (GHashTable *hash_table,
gconstpointer key)
{
GHashNode *node;
guint node_index;
guint hash_value;
guint step = 0;
/* Empty buckets have hash_value set to 0, and for tombstones, it's 1.
* We need to make sure our hash value is not one of these. */
hash_value = (* hash_table->hash_func) (key);
if (G_UNLIKELY (hash_value <= 1))
hash_value = 2;
node_index = hash_value % hash_table->mod;
node = &hash_table->nodes [node_index];
while (node->key_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->key_hash == hash_value)
{
if (hash_table->key_equal_func)
{
if (hash_table->key_equal_func (node->key, key))
break;
}
else if (node->key == key)
{
break;
}
}
step++;
node_index += step;
node_index &= hash_table->mask;
node = &hash_table->nodes [node_index];
}
return node_index;
}
/*
* g_hash_table_lookup_node_for_insertion:
* @hash_table: our #GHashTable
* @key: the key to lookup against
* @hash_return: key hash return location
* Return value: index of the described #GHashNode
*
* 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.
*/
static inline guint
g_hash_table_lookup_node_for_insertion (GHashTable *hash_table,
gconstpointer key,
guint *hash_return)
{
GHashNode *node;
guint node_index;
guint hash_value;
guint first_tombstone;
gboolean have_tombstone = FALSE;
guint step = 0;
/* Empty buckets have hash_value set to 0, and for tombstones, it's 1.
* We need to make sure our hash value is not one of these. */
hash_value = (* hash_table->hash_func) (key);
if (G_UNLIKELY (hash_value <= 1))
hash_value = 2;
*hash_return = hash_value;
node_index = hash_value % hash_table->mod;
node = &hash_table->nodes [node_index];
while (node->key_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->key_hash == hash_value)
{
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 (node->key_hash == 1 && !have_tombstone)
{
first_tombstone = node_index;
have_tombstone = TRUE;
}
step++;
node_index += step;
node_index &= hash_table->mask;
node = &hash_table->nodes [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,
GHashNode *node,
gboolean notify)
{
if (notify && hash_table->key_destroy_func)
hash_table->key_destroy_func (node->key);
if (notify && hash_table->value_destroy_func)
hash_table->value_destroy_func (node->value);
/* Erect tombstone */
node->key_hash = 1;
/* Be GC friendly */
node->key = NULL;
node->value = NULL;
hash_table->nnodes--;
}
/*
* 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;
for (i = 0; i < hash_table->size; i++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1)
{
if (notify && hash_table->key_destroy_func)
hash_table->key_destroy_func (node->key);
if (notify && hash_table->value_destroy_func)
hash_table->value_destroy_func (node->value);
}
}
/* We need to set node->key_hash = 0 for all nodes - might as well be GC
* friendly and clear everything */
memset (hash_table->nodes, 0, hash_table->size * sizeof (GHashNode));
hash_table->nnodes = 0;
hash_table->noccupied = 0;
}
/*
* 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)
{
GHashNode *new_nodes;
gint old_size;
gint i;
old_size = hash_table->size;
g_hash_table_set_shift_from_size (hash_table, hash_table->nnodes * 2);
new_nodes = g_new0 (GHashNode, hash_table->size);
for (i = 0; i < old_size; i++)
{
GHashNode *node = &hash_table->nodes [i];
GHashNode *new_node;
guint hash_val;
guint step = 0;
if (node->key_hash <= 1)
continue;
hash_val = node->key_hash % hash_table->mod;
new_node = &new_nodes [hash_val];
while (new_node->key_hash)
{
step++;
hash_val += step;
hash_val &= hash_table->mask;
new_node = &new_nodes [hash_val];
}
*new_node = *node;
}
g_free (hash_table->nodes);
hash_table->nodes = new_nodes;
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.
* Hash values 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: a function to check two keys for equality. This 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.
*
* Creates a new #GHashTable with a reference count of 1.
*
* 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: 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: 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->nodes = g_new0 (GHashNode, 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))
* {
* /&ast; do something with key and value &ast;/
* }
* ]|
*
* 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: a location to store the key, or %NULL.
* @value: 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;
GHashNode *node;
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;
}
node = &ri->hash_table->nodes [position];
}
while (node->key_hash <= 1);
if (key != NULL)
*key = node->key;
if (value != NULL)
*value = node->value;
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->hash_table->nodes [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_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_return_val_if_fail (hash_table->ref_count > 0, hash_table);
g_atomic_int_add (&hash_table->ref_count, 1);
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);
g_return_if_fail (hash_table->ref_count > 0);
if (g_atomic_int_exchange_and_add (&hash_table->ref_count, -1) - 1 == 0)
{
g_hash_table_remove_all_nodes (hash_table, TRUE);
g_free (hash_table->nodes);
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_return_if_fail (hash_table->ref_count > 0);
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: the associated value, or %NULL if the key is not found.
**/
gpointer
g_hash_table_lookup (GHashTable *hash_table,
gconstpointer key)
{
GHashNode *node;
guint node_index;
g_return_val_if_fail (hash_table != NULL, NULL);
node_index = g_hash_table_lookup_node (hash_table, key);
node = &hash_table->nodes [node_index];
return node->key_hash ? node->value : NULL;
}
/**
* g_hash_table_lookup_extended:
* @hash_table: a #GHashTable
* @lookup_key: the key to look up
* @orig_key: return location for the original key, or %NULL
* @value: 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.
*
* 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)
{
GHashNode *node;
guint node_index;
g_return_val_if_fail (hash_table != NULL, FALSE);
node_index = g_hash_table_lookup_node (hash_table, lookup_key);
node = &hash_table->nodes [node_index];
if (!node->key_hash)
return FALSE;
if (orig_key)
*orig_key = node->key;
if (value)
*value = node->value;
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)
{
GHashNode *node;
guint node_index;
guint key_hash;
guint old_hash;
g_return_if_fail (hash_table != NULL);
g_return_if_fail (hash_table->ref_count > 0);
node_index = g_hash_table_lookup_node_for_insertion (hash_table, key, &key_hash);
node = &hash_table->nodes [node_index];
old_hash = node->key_hash;
if (old_hash > 1)
{
if (keep_new_key)
{
if (hash_table->key_destroy_func)
hash_table->key_destroy_func (node->key);
node->key = key;
}
else
{
if (hash_table->key_destroy_func)
hash_table->key_destroy_func (key);
}
if (hash_table->value_destroy_func)
hash_table->value_destroy_func (node->value);
node->value = value;
}
else
{
node->key = key;
node->value = value;
node->key_hash = key_hash;
hash_table->nnodes++;
if (old_hash == 0)
{
/* 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
}
}
/**
* 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_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)
{
GHashNode *node;
guint node_index;
g_return_val_if_fail (hash_table != NULL, FALSE);
node_index = g_hash_table_lookup_node (hash_table, key);
node = &hash_table->nodes [node_index];
/* g_hash_table_lookup_node() never returns a tombstone, so this is safe */
if (!node->key_hash)
return FALSE;
g_hash_table_remove_node (hash_table, node, 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.
*
* Return value: %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.
*
* Return value: %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: our #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;
for (i = 0; i < hash_table->size; i++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1 && (* func) (node->key, node->value, user_data))
{
g_hash_table_remove_node (hash_table, node, notify);
deleted++;
}
}
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;
g_return_if_fail (hash_table != NULL);
g_return_if_fail (func != NULL);
for (i = 0; i < hash_table->size; i++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1)
(* func) (node->key, node->value, user_data);
}
}
/**
* 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: The value of the first key/value pair is returned, for which
* func 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;
g_return_val_if_fail (hash_table != NULL, NULL);
g_return_val_if_fail (predicate != NULL, NULL);
for (i = 0; i < hash_table->size; i++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1 && predicate (node->key, node->value, user_data))
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++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1)
retval = g_list_prepend (retval, node->key);
}
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++)
{
GHashNode *node = &hash_table->nodes [i];
if (node->key_hash > 1)
retval = g_list_prepend (retval, node->value);
}
return retval;
}
Reference in New Issue View Git Blame Copy Permalink