Show idtable.c syntax highlighted
/*
* $Id: idtable.c 13049 2007-03-11 18:29:58Z cbiere $
*
* Copyright (c) 2001-2003, Richard Eckart
*
*----------------------------------------------------------------------
* This file is part of gtk-gnutella.
*
* gtk-gnutella is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* gtk-gnutella 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with gtk-gnutella; if not, write to the Free Software
* Foundation, Inc.:
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*----------------------------------------------------------------------
*/
#include "common.h"
RCSID("$Id: idtable.c 13049 2007-03-11 18:29:58Z cbiere $")
#include "lib/glib-missing.h"
#include "lib/idtable.h"
#include "lib/misc.h"
#include "lib/walloc.h"
#include "lib/override.h" /* Must be the last header included */
#define IDTABLE_MASK (((guint32)-1) >> 1)
#define IDTABLE_BASE (IDTABLE_MASK + 1)
struct idtable {
GHashTable *ht;
guint32 last_id;
};
/***
*** Public functions
***/
/**
* Allocate new id table.
*/
idtable_t *
idtable_new(void)
{
static const idtable_t zero_idtable;
idtable_t *tbl;
tbl = walloc(sizeof *tbl);
*tbl = zero_idtable;
tbl->last_id = (random_raw() & IDTABLE_MASK) + IDTABLE_BASE;
tbl->ht = g_hash_table_new(NULL, NULL);
return tbl;
}
/**
* Free all memory occupied by this table. The table must not be used
* again after idtable_destroy call called on it.
*/
void
idtable_destroy(idtable_t *tbl)
{
g_hash_table_destroy(tbl->ht);
wfree(tbl, sizeof *tbl);
}
/**
* @returns TRUE if a id is already in use, returns FALSE if the id is
* not in use. If the id is outside the current table range it also returns
* FALSE. The table is not modified by this call.
*/
gboolean
idtable_is_id_used(const idtable_t *tbl, guint32 id)
{
gpointer key = GUINT_TO_POINTER(id);
return g_hash_table_lookup_extended(tbl->ht, key, NULL, NULL);
}
/**
* Get a id for the given value. The id can be used to look up the
* value later.
*/
guint32
idtable_new_id(idtable_t *tbl, gpointer value)
{
while (idtable_is_id_used(tbl, tbl->last_id)) {
tbl->last_id = ((tbl->last_id + 1) & IDTABLE_MASK) + IDTABLE_BASE;
}
g_hash_table_insert(tbl->ht, GUINT_TO_POINTER(tbl->last_id), value);
return tbl->last_id;
}
/**
* Replace the value of a give id. The id must already be in use.
*/
void
idtable_set_value(idtable_t *tbl, guint32 id, gpointer value)
{
g_assert(idtable_is_id_used(tbl, id));
g_hash_table_replace(tbl->ht, GUINT_TO_POINTER(id), value);
}
/**
* Fetch the value associated with the given id. The id must have been
* requested with idtable_request_id before and must not be accessed
* after it has been dropped by idtable_drop_id.
*/
gpointer
idtable_get_value(const idtable_t *tbl, guint32 id)
{
gpointer key, value;
gboolean found;
key = GUINT_TO_POINTER(id);
found = g_hash_table_lookup_extended(tbl->ht, key, NULL, &value);
g_assert(found);
return value;
}
/**
* Mark this id as unused. It will eventually be reissued.
*/
void
idtable_free_id(idtable_t *tbl, guint32 id)
{
g_assert(idtable_is_id_used(tbl, id));
g_hash_table_remove(tbl->ht, GUINT_TO_POINTER(id));
}
guint
idtable_ids(idtable_t *tbl)
{
return g_hash_table_size(tbl->ht);
}
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