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/*
$Id: salloc.c,v 1.2 2004/04/11 12:20:32 miguelfreitas Exp $
Copyright (C) 2000 Herbert Valerio Riedel <hvr@gnu.org>
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <string.h>
#include <stdlib.h>
#include <cdio/cdio.h>
/* Public headers */
#include <libvcd/types.h>
#include <libvcd/logging.h>
/* Private headers */
#include "vcd_assert.h"
#include "salloc.h"
#include "util.h"
static const char _rcsid[] = "$Id: salloc.c,v 1.2 2004/04/11 12:20:32 miguelfreitas Exp $";
#define VCD_SALLOC_CHUNK_SIZE 16
struct _VcdSalloc
{
uint8_t *data;
uint32_t len;
uint32_t alloced_chunks;
};
static void
_vcd_salloc_set_size (VcdSalloc *bitmap, uint32_t newlen)
{
uint32_t new_alloced_chunks;
vcd_assert (bitmap != NULL);
vcd_assert (newlen >= bitmap->len);
new_alloced_chunks = newlen / VCD_SALLOC_CHUNK_SIZE;
if (newlen % VCD_SALLOC_CHUNK_SIZE)
new_alloced_chunks++;
if (bitmap->alloced_chunks < new_alloced_chunks)
{
bitmap->data =
realloc (bitmap->data, new_alloced_chunks * VCD_SALLOC_CHUNK_SIZE);
memset (bitmap->data + (VCD_SALLOC_CHUNK_SIZE * bitmap->alloced_chunks),
0,
VCD_SALLOC_CHUNK_SIZE * (new_alloced_chunks -
bitmap->alloced_chunks));
bitmap->alloced_chunks = new_alloced_chunks;
}
bitmap->len = newlen;
}
static bool
_vcd_salloc_is_set (const VcdSalloc *bitmap, uint32_t sector)
{
unsigned _byte = sector / 8;
unsigned _bit = sector % 8;
if (_byte < bitmap->len)
return (bitmap->data[_byte] & (1 << _bit)) != 0;
else
return false;
}
static void
_vcd_salloc_set (VcdSalloc *bitmap, uint32_t sector)
{
unsigned _byte = sector / 8;
unsigned _bit = sector % 8;
if (_byte >= bitmap->len)
{
unsigned oldlen = bitmap->len;
_vcd_salloc_set_size (bitmap, _byte + 1);
memset (bitmap->data + oldlen, 0x00, _byte + 1 - oldlen);
}
bitmap->data[_byte] |= (1 << _bit);
}
static void
_vcd_salloc_unset (VcdSalloc *bitmap, uint32_t sector)
{
unsigned _byte = sector / 8;
unsigned _bit = sector % 8;
if (_byte >= bitmap->len)
vcd_assert_not_reached ();
bitmap->data[_byte] &= ~(1 << _bit);
}
/* exported */
uint32_t _vcd_salloc (VcdSalloc *bitmap, uint32_t hint, uint32_t size)
{
if (!size)
{
size++;
vcd_warn
("request of 0 sectors allocment fixed up to 1 sector (this is harmless)");
}
vcd_assert (size > 0);
if (hint != SECTOR_NIL)
{
uint32_t i;
for (i = 0; i < size; i++)
if (_vcd_salloc_is_set (bitmap, hint + i))
return SECTOR_NIL;
/* everything's ok for allocing */
i = size;
while (i)
_vcd_salloc_set (bitmap, hint + (--i));
/* we begin with highest byte, in order to minimizing
realloc's in sector_set */
return hint;
}
/* find the lowest possible ... */
hint = 0;
while (_vcd_salloc (bitmap, hint, size) == SECTOR_NIL)
hint++;
return hint;
}
void
_vcd_salloc_free (VcdSalloc *bitmap, uint32_t sec, uint32_t size)
{
uint32_t i;
for (i = 0; i < size; i++)
{
vcd_assert (_vcd_salloc_is_set (bitmap, sec + i));
_vcd_salloc_unset (bitmap, sec + i);
}
}
VcdSalloc *
_vcd_salloc_new (void)
{
VcdSalloc *newobj = _vcd_malloc (sizeof (VcdSalloc));
return newobj;
}
void
_vcd_salloc_destroy (VcdSalloc *bitmap)
{
vcd_assert (bitmap != NULL);
free (bitmap->data);
free (bitmap);
}
uint32_t _vcd_salloc_get_highest (const VcdSalloc *bitmap)
{
uint8_t last;
unsigned n;
vcd_assert (bitmap != NULL);
last = bitmap->data[bitmap->len - 1];
vcd_assert (last != 0);
n = 8;
while (n)
if ((1 << --n) & last)
break;
return (bitmap->len - 1) * 8 + n;
}
/*
* Local variables:
* c-file-style: "gnu"
* tab-width: 8
* indent-tabs-mode: nil
* End:
*/
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