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/*
* Copyright (C) 2004 Owen Taylor
*
* Authors:
* Owen Taylor <otaylor@redhat.com>
*
* Modified by the Glade developers
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include "glade-id-allocator.h"
#include <glib.h>
#include <string.h>
#define INITIAL_WORDS 4
struct _GladeIDAllocator
{
guint n_words;
guint32 *data;
};
/**
* glade_id_allocator_new:
*
* Returns: a new #GladeIDAllocator
*/
GladeIDAllocator *
glade_id_allocator_new (void)
{
GladeIDAllocator *allocator = g_slice_new (GladeIDAllocator);
allocator->n_words = INITIAL_WORDS;
allocator->data = g_new (guint32, INITIAL_WORDS);
memset (allocator->data, 0xff, INITIAL_WORDS * sizeof (guint32));
return allocator;
}
/**
* glade_id_allocator_destroy:
* @allocator: a #GladeIDAllocator
*
* Frees @allocator and its associated memory
*/
void
glade_id_allocator_destroy (GladeIDAllocator *allocator)
{
g_return_if_fail (allocator != NULL);
g_free (allocator->data);
g_slice_free (GladeIDAllocator, allocator);
}
static inline gint
first_set_bit (guint32 word)
{
static const char table[16] = {
4, 0, 1, 0,
2, 0, 1, 0,
3, 0, 1, 0,
2, 0, 1, 0
};
gint result = 0;
if ((word & 0xffff) == 0)
{
word >>= 16;
result += 16;
}
if ((word & 0xff) == 0)
{
word >>= 8;
result += 8;
}
if ((word & 0xf) == 0)
{
word >>= 4;
result += 4;
}
return result + table[word & 0xf];
}
/**
* glade_id_allocator_allocate:
* @allocator: a #GladeIDAllocator
*
* TODO: write me
* Returns: the id
*/
guint
glade_id_allocator_allocate (GladeIDAllocator *allocator)
{
guint i;
g_return_val_if_fail (allocator != NULL, 0);
for (i = 0; i < allocator->n_words; i++)
{
if (allocator->data[i] != 0)
{
gint free_bit = first_set_bit (allocator->data[i]);
allocator->data[i] &= ~(1 << free_bit);
return 32 * i + free_bit + 1;
}
}
{
guint n_words = allocator->n_words;
allocator->data = g_renew (guint32, allocator->data, n_words * 2);
memset (&allocator->data[n_words], 0xff, n_words * sizeof (guint32));
allocator->n_words = n_words * 2;
allocator->data[n_words] = 0xffffffff - 1;
return 32 * n_words + 1;
}
}
/**
* glade_id_allocator_release:
* @allocator: a #GladeIDAllocator
* @id: the id given by glade_id_allocator_allocate()
*
* TODO: write me
*/
void
glade_id_allocator_release (GladeIDAllocator *allocator, guint id)
{
guint word_idx;
g_return_if_fail (allocator != NULL);
/* Allocated ids start with 1 */
if (id > 0)
{
id = id - 1;
word_idx = id >> 5;
/* Tollerate releasing ids that were never allocated with the allocator
* or are out of range... when we load Glade files with huge numbers it happens
* that loaded unallocated ids are out of range
*/
if (word_idx < allocator->n_words)
allocator->data[word_idx] |= 1 << (id & 31);
}
}
#ifdef GLADE_ID_ALLOCATOR_TEST
int
main (int argc, char **argv)
{
GladeIDAllocator *allocator = glade_id_allocator_new ();
guint i;
guint iter;
for (i = 0; i < 1000; i++)
{
guint id = glade_id_allocator_allocate (allocator);
g_assert (id == i);
}
for (i = 0; i < 1000; i++)
glade_id_allocator_release (allocator, i);
for (iter = 0; iter < 10000; iter++)
{
for (i = 0; i < 1000; i++)
glade_id_allocator_allocate (allocator);
for (i = 0; i < 1000; i++)
glade_id_allocator_release (allocator, i);
}
glade_id_allocator_destroy (allocator);
return 0;
}
#endif
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