luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2024-12-29 08:56:15 +01:00
Code Issues Packages Projects Releases Wiki Activity
8ddfbb308b
glib/glib/ghash.c
Hans Petter Jansson d3074a748f ghash: Fix out-of-range use of signed integer 
We were mistakenly shifting a signed int literal by up to 31 places.
Specify unsigned int instead.

Closes #1570
2018-10-12 13:09:39 +02:00

2453 lines
75 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 2.1 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, see <http://www.gnu.org/licenses/>.
*/
/*
* 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 "ghash.h"
#include "glib-private.h"
#include "gstrfuncs.h"
#include "gatomic.h"
#include "gtestutils.h"
#include "gslice.h"
#include "grefcount.h"
/* The following #pragma is here so we can do this...
*
* #ifndef USE_SMALL_ARRAYS
* is_big = TRUE;
* #endif
* return is_big ? *(((gpointer *) a) + index) : GUINT_TO_POINTER (*(((guint *) a) + index));
*
* ...instead of this...
*
* #ifndef USE_SMALL_ARRAYS
* return *(((gpointer *) a) + index);
* #else
* return is_big ? *(((gpointer *) a) + index) : GUINT_TO_POINTER (*(((guint *) a) + index));
* #endif
*
* ...and still compile successfully when -Werror=duplicated-branches is passed. */
#pragma GCC diagnostic ignored "-Wduplicated-branches"
/**
* 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().
*
* 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. The functions
* g_hash_table_add() and g_hash_table_contains() are designed to be
* used when using #GHashTable this way.
*
* #GHashTable is not designed to be statically initialised with keys and
* values known at compile time. To build a static hash table, use a tool such
* as [gperf](https://www.gnu.org/software/gperf/).
*/
/**
* GHashTable:
*
* The #GHashTable struct is an opaque data structure to represent a
* [Hash Table][glib-Hash-Tables]. 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](https://lwn.net/Articles/474912/).
*
* 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)
/* If int is smaller than void * on our arch, we start out with
* int-sized keys and values and resize to pointer-sized entries as
* needed. This saves a good amount of memory when the HT is being
* used with e.g. GUINT_TO_POINTER(). */
#define BIG_ENTRY_SIZE (SIZEOF_VOID_P)
#define SMALL_ENTRY_SIZE (SIZEOF_INT)
#if SMALL_ENTRY_SIZE < BIG_ENTRY_SIZE
# define USE_SMALL_ARRAYS
#endif
struct _GHashTable
{
gint size;
gint mod;
guint mask;
gint nnodes;
gint noccupied; /* nnodes + tombstones */
guint have_big_keys : 1;
guint have_big_values : 1;
gpointer keys;
guint *hashes;
gpointer values;
GHashFunc hash_func;
GEqualFunc key_equal_func;
gatomicrefcount 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;
G_STATIC_ASSERT (sizeof (GHashTableIter) == sizeof (RealIter));
G_STATIC_ASSERT (_g_alignof (GHashTableIter) >= _g_alignof (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)
{
hash_table->size = 1 << shift;
hash_table->mod = prime_mod [shift];
/* hash_table->size is always a power of two, so we can calculate the mask
* by simply subtracting 1 from it. The leading assertion ensures that
* we're really dealing with a power of two. */
g_assert ((hash_table->size & (hash_table->size - 1)) == 0);
hash_table->mask = hash_table->size - 1;
}
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);
}
static inline gpointer
g_hash_table_realloc_key_or_value_array (gpointer a, guint size, G_GNUC_UNUSED gboolean is_big)
{
#ifdef USE_SMALL_ARRAYS
return g_realloc (a, size * (is_big ? BIG_ENTRY_SIZE : SMALL_ENTRY_SIZE));
#else
return g_renew (gpointer, a, size);
#endif
}
static inline gpointer
g_hash_table_fetch_key_or_value (gpointer a, guint index, gboolean is_big)
{
#ifndef USE_SMALL_ARRAYS
is_big = TRUE;
#endif
return is_big ? *(((gpointer *) a) + index) : GUINT_TO_POINTER (*(((guint *) a) + index));
}
static inline void
g_hash_table_assign_key_or_value (gpointer a, guint index, gboolean is_big, gpointer v)
{
#ifndef USE_SMALL_ARRAYS
is_big = TRUE;
#endif
if (is_big)
*(((gpointer *) a) + index) = v;
else
*(((guint *) a) + index) = GPOINTER_TO_UINT (v);
}
static inline gpointer
g_hash_table_evict_key_or_value (gpointer a, guint index, gboolean is_big, gpointer v)
{
#ifndef USE_SMALL_ARRAYS
is_big = TRUE;
#endif
if (is_big)
{
gpointer r = *(((gpointer *) a) + index);
*(((gpointer *) a) + index) = v;
return r;
}
else
{
gpointer r = GUINT_TO_POINTER (*(((guint *) a) + index));
*(((guint *) a) + index) = GPOINTER_TO_UINT (v);
return r;
}
}
static inline guint
g_hash_table_hash_to_index (GHashTable *hash_table, guint hash)
{
/* Multiply the hash by a small prime before applying the modulo. This
* prevents the table from becoming densely packed, even with a poor hash
* function. A densely packed table would have poor performance on
* workloads with many failed lookups or a high degree of churn. */
return (hash * 11) % hash_table->mod;
}
/*
* 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;
/* If this happens, then the application is probably doing too much work
* from a destroy notifier. The alternative would be to crash any second
* (as keys, etc. will be NULL).
* Applications need to either use g_hash_table_destroy, or ensure the hash
* table is empty prior to removing the last reference using g_hash_table_unref(). */
g_assert (!g_atomic_ref_count_compare (&hash_table->ref_count, 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 = g_hash_table_hash_to_index (hash_table, hash_value);
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 = g_hash_table_fetch_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys);
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 = g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys);
value = g_hash_table_fetch_key_or_value (hash_table->values, i, hash_table->have_big_values);
/* Erect tombstone */
hash_table->hashes[i] = TOMBSTONE_HASH_VALUE;
/* Be GC friendly */
g_hash_table_assign_key_or_value (hash_table->keys, i, hash_table->have_big_keys, NULL);
g_hash_table_assign_key_or_value (hash_table->values, i, hash_table->have_big_values, 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,
gboolean destruction)
{
int i;
gpointer key;
gpointer value;
gint old_size;
gpointer *old_keys;
gpointer *old_values;
guint *old_hashes;
/* If the hash table is already empty, there is nothing to be done. */
if (hash_table->nnodes == 0)
return;
hash_table->nnodes = 0;
hash_table->noccupied = 0;
if (!notify ||
(hash_table->key_destroy_func == NULL &&
hash_table->value_destroy_func == NULL))
{
if (!destruction)
{
memset (hash_table->hashes, 0, hash_table->size * sizeof (guint));
#ifdef USE_SMALL_ARRAYS
memset (hash_table->keys, 0, hash_table->size * (hash_table->have_big_keys ? BIG_ENTRY_SIZE : SMALL_ENTRY_SIZE));
memset (hash_table->values, 0, hash_table->size * (hash_table->have_big_values ? BIG_ENTRY_SIZE : SMALL_ENTRY_SIZE));
#else
memset (hash_table->keys, 0, hash_table->size * sizeof (gpointer));
memset (hash_table->values, 0, hash_table->size * sizeof (gpointer));
#endif
}
return;
}
/* Keep the old storage space around to iterate over it. */
old_size = hash_table->size;
old_keys = hash_table->keys;
old_values = hash_table->values;
old_hashes = hash_table->hashes;
/* Now create a new storage space; If the table is destroyed we can use the
* shortcut of not creating a new storage. This saves the allocation at the
* cost of not allowing any recursive access.
* However, the application doesn't own any reference anymore, so access
* is not allowed. If accesses are done, then either an assert or crash
* *will* happen. */
g_hash_table_set_shift (hash_table, HASH_TABLE_MIN_SHIFT);
if (!destruction)
{
hash_table->keys = g_hash_table_realloc_key_or_value_array (NULL, hash_table->size, FALSE);
hash_table->values = hash_table->keys;
hash_table->hashes = g_new0 (guint, hash_table->size);
}
else
{
hash_table->keys = NULL;
hash_table->values = NULL;
hash_table->hashes = NULL;
}
for (i = 0; i < old_size; i++)
{
if (HASH_IS_REAL (old_hashes[i]))
{
key = g_hash_table_fetch_key_or_value (old_keys, i, hash_table->have_big_keys);
value = g_hash_table_fetch_key_or_value (old_values, i, hash_table->have_big_values);
old_hashes[i] = UNUSED_HASH_VALUE;
g_hash_table_assign_key_or_value (old_keys, i, hash_table->have_big_keys, NULL);
g_hash_table_assign_key_or_value (old_values, i, hash_table->have_big_values, 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);
}
}
hash_table->have_big_keys = FALSE;
hash_table->have_big_values = FALSE;
/* Destroy old storage space. */
if (old_keys != old_values)
g_free (old_values);
g_free (old_keys);
g_free (old_hashes);
}
static void
realloc_arrays (GHashTable *hash_table, gboolean is_a_set)
{
hash_table->hashes = g_renew (guint, hash_table->hashes, hash_table->size);
hash_table->keys = g_hash_table_realloc_key_or_value_array (hash_table->keys, hash_table->size, hash_table->have_big_keys);
if (is_a_set)
hash_table->values = hash_table->keys;
else
hash_table->values = g_hash_table_realloc_key_or_value_array (hash_table->values, hash_table->size, hash_table->have_big_values);
}
/* When resizing the table in place, we use a temporary bit array to keep
* track of which entries have been assigned a proper location in the new
* table layout.
*
* Each bit corresponds to a bucket. A bit is set if an entry was assigned
* its corresponding location during the resize and thus should not be
* evicted. The array starts out cleared to zero. */
static inline gboolean
get_status_bit (const guint32 *bitmap, guint index)
{
return (bitmap[index / 32] >> (index % 32)) & 1;
}
static inline void
set_status_bit (guint32 *bitmap, guint index)
{
bitmap[index / 32] |= 1U << (index % 32);
}
/* By calling dedicated resize functions for sets and maps, we avoid 2x
* test-and-branch per key in the inner loop. This yields a small
* performance improvement at the cost of a bit of macro gunk. */
#define DEFINE_RESIZE_FUNC(fname) \
static void fname (GHashTable *hash_table, guint old_size, guint32 *reallocated_buckets_bitmap) \
{ \
guint i; \
\
for (i = 0; i < old_size; i++) \
{ \
guint node_hash = hash_table->hashes[i]; \
gpointer key, value G_GNUC_UNUSED; \
\
if (!HASH_IS_REAL (node_hash)) \
{ \
/* Clear tombstones */ \
hash_table->hashes[i] = UNUSED_HASH_VALUE; \
continue; \
} \
\
/* Skip entries relocated through eviction */ \
if (get_status_bit (reallocated_buckets_bitmap, i)) \
continue; \
\
hash_table->hashes[i] = UNUSED_HASH_VALUE; \
EVICT_KEYVAL (hash_table, i, NULL, NULL, key, value); \
\
for (;;) \
{ \
guint hash_val; \
guint replaced_hash; \
guint step = 0; \
\
hash_val = g_hash_table_hash_to_index (hash_table, node_hash); \
\
while (get_status_bit (reallocated_buckets_bitmap, hash_val)) \
{ \
step++; \
hash_val += step; \
hash_val &= hash_table->mask; \
} \
\
set_status_bit (reallocated_buckets_bitmap, hash_val); \
\
replaced_hash = hash_table->hashes[hash_val]; \
hash_table->hashes[hash_val] = node_hash; \
if (!HASH_IS_REAL (replaced_hash)) \
{ \
ASSIGN_KEYVAL (hash_table, hash_val, key, value); \
break; \
} \
\
node_hash = replaced_hash; \
EVICT_KEYVAL (hash_table, hash_val, key, value, key, value); \
} \
} \
}
#define ASSIGN_KEYVAL(ht, index, key, value) G_STMT_START{ \
g_hash_table_assign_key_or_value ((ht)->keys, (index), (ht)->have_big_keys, (key)); \
g_hash_table_assign_key_or_value ((ht)->values, (index), (ht)->have_big_values, (value)); \
}G_STMT_END
#define EVICT_KEYVAL(ht, index, key, value, outkey, outvalue) G_STMT_START{ \
(outkey) = g_hash_table_evict_key_or_value ((ht)->keys, (index), (ht)->have_big_keys, (key)); \
(outvalue) = g_hash_table_evict_key_or_value ((ht)->values, (index), (ht)->have_big_values, (value)); \
}G_STMT_END
DEFINE_RESIZE_FUNC (resize_map)
#undef ASSIGN_KEYVAL
#undef EVICT_KEYVAL
#define ASSIGN_KEYVAL(ht, index, key, value) G_STMT_START{ \
g_hash_table_assign_key_or_value ((ht)->keys, (index), (ht)->have_big_keys, (key)); \
}G_STMT_END
#define EVICT_KEYVAL(ht, index, key, value, outkey, outvalue) G_STMT_START{ \
(outkey) = g_hash_table_evict_key_or_value ((ht)->keys, (index), (ht)->have_big_keys, (key)); \
}G_STMT_END
DEFINE_RESIZE_FUNC (resize_set)
#undef ASSIGN_KEYVAL
#undef EVICT_KEYVAL
/*
* 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)
{
guint32 *reallocated_buckets_bitmap;
guint old_size;
gboolean is_a_set;
old_size = hash_table->size;
is_a_set = hash_table->keys == hash_table->values;
/* The outer checks in g_hash_table_maybe_resize() will only consider
* cleanup/resize when the load factor goes below .25 (1/4, ignoring
* tombstones) or above .9375 (15/16, including tombstones).
*
* Once this happens, tombstones will always be cleaned out. If our
* load sans tombstones is greater than .75 (1/1.333, see below), we'll
* take this opportunity to grow the table too.
*
* Immediately after growing, the load factor will be in the range
* .375 .. .469. After shrinking, it will be exactly .5. */
g_hash_table_set_shift_from_size (hash_table, hash_table->nnodes * 1.333);
if (hash_table->size > old_size)
{
realloc_arrays (hash_table, is_a_set);
memset (&hash_table->hashes[old_size], 0, (hash_table->size - old_size) * sizeof (guint));
reallocated_buckets_bitmap = g_new0 (guint32, (hash_table->size + 31) / 32);
}
else
{
reallocated_buckets_bitmap = g_new0 (guint32, (old_size + 31) / 32);
}
if (is_a_set)
resize_set (hash_table, old_size, reallocated_buckets_bitmap);
else
resize_map (hash_table, old_size, reallocated_buckets_bitmap);
g_free (reallocated_buckets_bitmap);
if (hash_table->size < old_size)
realloc_arrays (hash_table, is_a_set);
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);
}
#ifdef USE_SMALL_ARRAYS
static inline gboolean
entry_is_big (gpointer v)
{
return (((guintptr) v) >> ((BIG_ENTRY_SIZE - SMALL_ENTRY_SIZE) * 8)) != 0;
}
static inline gboolean
g_hash_table_maybe_make_big_keys_or_values (gpointer *a_p, gpointer v, gint ht_size)
{
if (entry_is_big (v))
{
guint *a = (guint *) *a_p;
gpointer *a_new;
gint i;
a_new = g_new (gpointer, ht_size);
for (i = 0; i < ht_size; i++)
{
a_new[i] = GUINT_TO_POINTER (a[i]);
}
g_free (a);
*a_p = a_new;
return TRUE;
}
return FALSE;
}
#endif
static inline void
g_hash_table_ensure_keyval_fits (GHashTable *hash_table, gpointer key, gpointer value)
{
gboolean is_a_set = (hash_table->keys == hash_table->values);
#ifdef USE_SMALL_ARRAYS
/* Convert from set to map? */
if (is_a_set)
{
if (hash_table->have_big_keys)
{
if (key != value)
hash_table->values = g_memdup (hash_table->keys, sizeof (gpointer) * hash_table->size);
/* Keys and values are both big now, so no need for further checks */
return;
}
else
{
if (key != value)
{
hash_table->values = g_memdup (hash_table->keys, sizeof (guint) * hash_table->size);
is_a_set = FALSE;
}
}
}
/* Make keys big? */
if (!hash_table->have_big_keys)
{
hash_table->have_big_keys = g_hash_table_maybe_make_big_keys_or_values (&hash_table->keys, key, hash_table->size);
if (is_a_set)
{
hash_table->values = hash_table->keys;
hash_table->have_big_values = hash_table->have_big_keys;
}
}
/* Make values big? */
if (!is_a_set && !hash_table->have_big_values)
{
hash_table->have_big_values = g_hash_table_maybe_make_big_keys_or_values (&hash_table->values, value, hash_table->size);
}
#else
/* Just split if necessary */
if (is_a_set && key != value)
hash_table->values = g_memdup (hash_table->keys, sizeof (gpointer) * hash_table->size);
#endif
}
/**
* 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. @key_equal_func is called with the key from the hash table
* as its first parameter, and the user-provided key to check against as
* its second.
*
* Returns: 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: (nullable): 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: (nullable): 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.
*
* Since version 2.42 it is permissible for destroy notify functions to
* recursively remove further items from the hash table. This is only
* permissible if the application still holds a reference to the hash table.
* This means that you may need to ensure that the hash table is empty by
* calling g_hash_table_remove_all() before releasing the last reference using
* g_hash_table_unref().
*
* Returns: 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);
g_atomic_ref_count_init (&hash_table->ref_count);
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;
#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_hash_table_realloc_key_or_value_array (NULL, hash_table->size, FALSE);
hash_table->values = hash_table->keys;
hash_table->hashes = g_new0 (guint, hash_table->size);
#ifdef USE_SMALL_ARRAYS
hash_table->have_big_keys = FALSE;
hash_table->have_big_values = FALSE;
#else
hash_table->have_big_keys = TRUE;
hash_table->have_big_values = TRUE;
#endif
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.
* |[<!-- language="C" -->
* 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: (out) (optional): a location to store the key
* @value: (out) (optional) (nullable): a location to store the value
*
* 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.
*
* Returns: %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 = g_hash_table_fetch_key_or_value (ri->hash_table->keys, position, ri->hash_table->have_big_keys);
if (value != NULL)
*value = g_hash_table_fetch_key_or_value (ri->hash_table->values, position, ri->hash_table->have_big_values);
ri->position = position;
return TRUE;
}
/**
* g_hash_table_iter_get_hash_table:
* @iter: an initialized #GHashTableIter
*
* Returns the #GHashTable associated with @iter.
*
* Returns: 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.
*
* It is safe to continue iterating the #GHashTable afterward:
* |[<!-- language="C" -->
* while (g_hash_table_iter_next (&iter, &key, &value))
* {
* if (condition)
* g_hash_table_iter_remove (&iter);
* }
* ]|
*
* 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: (nullable): 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.
*
* Returns: %TRUE if the key did not exist yet
*/
static gboolean
g_hash_table_insert_node (GHashTable *hash_table,
guint node_index,
guint key_hash,
gpointer new_key,
gpointer new_value,
gboolean keep_new_key,
gboolean reusing_key)
{
gboolean already_exists;
guint old_hash;
gpointer key_to_free = NULL;
gpointer key_to_keep = NULL;
gpointer value_to_free = NULL;
old_hash = hash_table->hashes[node_index];
already_exists = HASH_IS_REAL (old_hash);
/* Proceed in three steps. First, deal with the key because it is the
* most complicated. Then consider if we need to split the table in
* two (because writing the value will result in the set invariant
* becoming broken). Then deal with the value.
*
* There are three cases for the key:
*
* - entry already exists in table, reusing key:
* free the just-passed-in new_key and use the existing value
*
* - entry already exists in table, not reusing key:
* free the entry in the table, use the new key
*
* - entry not already in table:
* use the new key, free nothing
*
* We update the hash at the same time...
*/
if (already_exists)
{
/* Note: we must record the old value before writing the new key
* because we might change the value in the event that the two
* arrays are shared.
*/
value_to_free = g_hash_table_fetch_key_or_value (hash_table->values, node_index, hash_table->have_big_values);
if (keep_new_key)
{
key_to_free = g_hash_table_fetch_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys);
key_to_keep = new_key;
}
else
{
key_to_free = new_key;
key_to_keep = g_hash_table_fetch_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys);
}
}
else
{
hash_table->hashes[node_index] = key_hash;
key_to_keep = new_key;
}
/* Resize key/value arrays and split table as necessary */
g_hash_table_ensure_keyval_fits (hash_table, key_to_keep, new_value);
g_hash_table_assign_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys, key_to_keep);
/* Step 3: Actually do the write */
g_hash_table_assign_key_or_value (hash_table->values, node_index, hash_table->have_big_values, new_value);
/* Now, the bookkeeping... */
if (!already_exists)
{
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 (already_exists)
{
if (hash_table->key_destroy_func && !reusing_key)
(* hash_table->key_destroy_func) (key_to_free);
if (hash_table->value_destroy_func)
(* hash_table->value_destroy_func) (value_to_free);
}
return !already_exists;
}
/**
* 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 = g_hash_table_fetch_key_or_value (ri->hash_table->keys, ri->position, ri->hash_table->have_big_keys);
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.
*
* Returns: 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_ref_count_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_ref_count_dec (&hash_table->ref_count))
{
g_hash_table_remove_all_nodes (hash_table, TRUE, 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().
*
* Returns: (nullable): 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])
? g_hash_table_fetch_key_or_value (hash_table->values, node_index, hash_table->have_big_values)
: NULL;
}
/**
* g_hash_table_lookup_extended:
* @hash_table: a #GHashTable
* @lookup_key: the key to look up
* @orig_key: (out) (optional): return location for the original key
* @value: (out) (optional) (nullable): return location for the value associated
* with the key
*
* 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.
*
* Returns: %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]))
{
if (orig_key != NULL)
*orig_key = NULL;
if (value != NULL)
*value = NULL;
return FALSE;
}
if (orig_key)
*orig_key = g_hash_table_fetch_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys);
if (value)
*value = g_hash_table_fetch_key_or_value (hash_table->values, node_index, hash_table->have_big_values);
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.
*
* Returns: %TRUE if the key did not exist yet
*/
static gboolean
g_hash_table_insert_internal (GHashTable *hash_table,
gpointer key,
gpointer value,
gboolean keep_new_key)
{
guint key_hash;
guint node_index;
g_return_val_if_fail (hash_table != NULL, FALSE);
node_index = g_hash_table_lookup_node (hash_table, key, &key_hash);
return 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.
*
* Starting from GLib 2.40, this function returns a boolean value to
* indicate whether the newly added value was already in the hash table
* or not.
*
* Returns: %TRUE if the key did not exist yet
*/
gboolean
g_hash_table_insert (GHashTable *hash_table,
gpointer key,
gpointer value)
{
return 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.
*
* Starting from GLib 2.40, this function returns a boolean value to
* indicate whether the newly added value was already in the hash table
* or not.
*
* Returns: %TRUE if the key did not exist yet
*/
gboolean
g_hash_table_replace (GHashTable *hash_table,
gpointer key,
gpointer value)
{
return 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.
*
* Starting from GLib 2.40, this function returns a boolean value to
* indicate whether the newly added value was already in the hash table
* or not.
*
* Returns: %TRUE if the key did not exist yet
*
* Since: 2.32
*/
gboolean
g_hash_table_add (GHashTable *hash_table,
gpointer key)
{
return 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.
*
* Returns: %TRUE if @key is in @hash_table, %FALSE otherwise.
*
* 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
* Returns: %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_steal_extended:
* @hash_table: a #GHashTable
* @lookup_key: the key to look up
* @stolen_key: (out) (optional) (transfer full): return location for the
* original key
* @stolen_value: (out) (optional) (nullable) (transfer full): return location
* for the value associated with the key
*
* Looks up a key in the #GHashTable, stealing the original key and the
* associated value and returning %TRUE if the key was found. If the key was
* not found, %FALSE is returned.
*
* If found, the stolen key and value are removed from the hash table without
* calling the key and value destroy functions, and ownership is transferred to
* the caller of this method; as with g_hash_table_steal().
*
* You can pass %NULL for @lookup_key, provided the hash and equal functions
* of @hash_table are %NULL-safe.
*
* Returns: %TRUE if the key was found in the #GHashTable
* Since: 2.58
*/
gboolean
g_hash_table_steal_extended (GHashTable *hash_table,
gconstpointer lookup_key,
gpointer *stolen_key,
gpointer *stolen_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]))
{
if (stolen_key != NULL)
*stolen_key = NULL;
if (stolen_value != NULL)
*stolen_value = NULL;
return FALSE;
}
if (stolen_key != NULL)
{
*stolen_key = g_hash_table_fetch_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys);
g_hash_table_assign_key_or_value (hash_table->keys, node_index, hash_table->have_big_keys, NULL);
}
if (stolen_value != NULL)
{
*stolen_value = g_hash_table_fetch_key_or_value (hash_table->values, node_index, hash_table->have_big_values);
g_hash_table_assign_key_or_value (hash_table->values, node_index, hash_table->have_big_values, NULL);
}
g_hash_table_remove_node (hash_table, node_index, FALSE);
g_hash_table_maybe_resize (hash_table);
#ifndef G_DISABLE_ASSERT
hash_table->version++;
#endif
return TRUE;
}
/**
* 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, FALSE);
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, 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 = g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys);
gpointer node_value = g_hash_table_fetch_key_or_value (hash_table->values, i, hash_table->have_big_values);
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.
*
* Returns: 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.
*
* Returns: 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 = g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys);
gpointer node_value = g_hash_table_fetch_key_or_value (hash_table->values, i, hash_table->have_big_values);
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).
*
* Returns: (nullable): 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 = g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys);
gpointer node_value = g_hash_table_fetch_key_or_value (hash_table->values, i, hash_table->have_big_values);
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.
*
* Returns: 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 changes to the hash release those keys.
*
* This iterates over every entry in the hash table to build its return value.
* To iterate over the entries in a #GHashTable more efficiently, use a
* #GHashTableIter.
*
* Returns: (transfer container): 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, g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys));
}
return retval;
}
/**
* g_hash_table_get_keys_as_array:
* @hash_table: a #GHashTable
* @length: (out): the length of the returned array
*
* Retrieves every key inside @hash_table, as an array.
*
* The returned array is %NULL-terminated but may contain %NULL as a
* key. Use @length to determine the true length if it's possible that
* %NULL was used as the value for a key.
*
* Note: in the common case of a string-keyed #GHashTable, the return
* value of this function can be conveniently cast to (const gchar **).
*
* This iterates over every entry in the hash table to build its return value.
* To iterate over the entries in a #GHashTable more efficiently, use a
* #GHashTableIter.
*
* You should always free the return result with g_free(). In the
* above-mentioned case of a string-keyed hash table, it may be
* appropriate to use g_strfreev() if you call g_hash_table_steal_all()
* first to transfer ownership of the keys.
*
* Returns: (array length=length) (transfer container): a
* %NULL-terminated array containing each key from the table.
*
* Since: 2.40
**/
gpointer *
g_hash_table_get_keys_as_array (GHashTable *hash_table,
guint *length)
{
gpointer *result;
guint i, j = 0;
result = g_new (gpointer, hash_table->nnodes + 1);
for (i = 0; i < hash_table->size; i++)
{
if (HASH_IS_REAL (hash_table->hashes[i]))
result[j++] = g_hash_table_fetch_key_or_value (hash_table->keys, i, hash_table->have_big_keys);
}
g_assert_cmpint (j, ==, hash_table->nnodes);
result[j] = NULL;
if (length)
*length = j;
return result;
}
/**
* 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.
*
* This iterates over every entry in the hash table to build its return value.
* To iterate over the entries in a #GHashTable more efficiently, use a
* #GHashTableIter.
*
* Returns: (transfer container): 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, g_hash_table_fetch_key_or_value (hash_table->values, i, hash_table->have_big_values));
}
return retval;
}
/* Hash functions.
*/
/**
* g_str_equal:
* @v1: (not nullable): a key
* @v2: (not nullable): 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.
*
* This function is typically used for hash table comparisons, but can be used
* for general purpose comparisons of non-%NULL strings. For a %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: (not nullable): 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.
*
* Note that this function may not be a perfect fit for all use cases.
* For example, it produces some hash collisions with strings as short
* as 2.
*
* 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: (nullable): 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: (nullable): a key
* @v2: (nullable): 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: (not nullable): a pointer to a #gint key
* @v2: (not nullable): 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: (not nullable): 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: (not nullable): a pointer to a #gint64 key
* @v2: (not nullable): 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: (not nullable): 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: (not nullable): a pointer to a #gdouble key
* @v2: (not nullable): 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: (not nullable): 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;
}
Reference in New Issue View Git Blame Copy Permalink