mutter/cogl/cogl-bitmask.c
Neil Roberts f23b12a886 cogl-bitmask: Add _cogl_bitmask_popcount
This returns a population count of all the bits that are set in the
bitmask.

There is now also a _cogl_bitmask_popcount_upto which counts the
number of bits set up to but not including the given bit index. This
will be useful to determine the number of uniform overrides to skip if
we tightly pack the values in an array.

The test-bitmask test has been modified to check these two functions.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-11-16 16:32:11 +00:00

312 lines
8.5 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2010 Intel Corporation.
*
* 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, see <http://www.gnu.org/licenses/>.
*
*
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <glib.h>
#include <string.h>
#include "cogl-bitmask.h"
#include "cogl-util.h"
#include "cogl-flags.h"
/* This code assumes that we can cast an unsigned long to a pointer
and back without losing any data */
G_STATIC_ASSERT (sizeof (unsigned long) <= sizeof (void *));
#define ARRAY_INDEX(bit_num) \
((bit_num) / (sizeof (unsigned long) * 8))
#define BIT_INDEX(bit_num) \
((bit_num) & (sizeof (unsigned long) * 8 - 1))
#define BIT_MASK(bit_num) \
(1UL << BIT_INDEX (bit_num))
gboolean
_cogl_bitmask_get_from_array (const CoglBitmask *bitmask,
unsigned int bit_num)
{
GArray *array = (GArray *) *bitmask;
/* If the index is off the end of the array then assume the bit is
not set */
if (bit_num >= sizeof (unsigned long) * 8 * array->len)
return FALSE;
else
return !!(g_array_index (array, unsigned long, ARRAY_INDEX (bit_num)) &
BIT_MASK (bit_num));
}
static void
_cogl_bitmask_convert_to_array (CoglBitmask *bitmask)
{
GArray *array;
/* Fetch the old values */
unsigned long old_values = _cogl_bitmask_to_bits (bitmask);
array = g_array_new (FALSE, /* not zero-terminated */
TRUE, /* do clear new entries */
sizeof (unsigned long));
/* Copy the old values back in */
g_array_append_val (array, old_values);
*bitmask = (struct _CoglBitmaskImaginaryType *) array;
}
void
_cogl_bitmask_set_in_array (CoglBitmask *bitmask,
unsigned int bit_num,
gboolean value)
{
GArray *array;
unsigned int array_index;
unsigned long new_value_mask;
/* If the bitmask is not already an array then we need to allocate one */
if (!_cogl_bitmask_has_array (bitmask))
_cogl_bitmask_convert_to_array (bitmask);
array = (GArray *) *bitmask;
array_index = ARRAY_INDEX (bit_num);
/* Grow the array if necessary. This will clear the new data */
if (array_index >= array->len)
g_array_set_size (array, array_index + 1);
new_value_mask = BIT_MASK (bit_num);
if (value)
g_array_index (array, unsigned long, array_index) |= new_value_mask;
else
g_array_index (array, unsigned long, array_index) &= ~new_value_mask;
}
void
_cogl_bitmask_set_bits (CoglBitmask *dst,
const CoglBitmask *src)
{
if (_cogl_bitmask_has_array (src))
{
GArray *src_array, *dst_array;
int i;
if (!_cogl_bitmask_has_array (dst))
_cogl_bitmask_convert_to_array (dst);
dst_array = (GArray *) *dst;
src_array = (GArray *) *src;
if (dst_array->len < src_array->len)
g_array_set_size (dst_array, src_array->len);
for (i = 0; i < src_array->len; i++)
g_array_index (dst_array, unsigned long, i) |=
g_array_index (src_array, unsigned long, i);
}
else if (_cogl_bitmask_has_array (dst))
{
GArray *dst_array;
dst_array = (GArray *) *dst;
g_array_index (dst_array, unsigned long, 0) |=
_cogl_bitmask_to_bits (src);
}
else
*dst = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (dst) |
_cogl_bitmask_to_bits (src));
}
void
_cogl_bitmask_set_range_in_array (CoglBitmask *bitmask,
unsigned int n_bits,
gboolean value)
{
GArray *array;
unsigned int array_index, bit_index;
if (n_bits == 0)
return;
/* If the bitmask is not already an array then we need to allocate one */
if (!_cogl_bitmask_has_array (bitmask))
_cogl_bitmask_convert_to_array (bitmask);
array = (GArray *) *bitmask;
/* Get the array index of the top most value that will be touched */
array_index = ARRAY_INDEX (n_bits - 1);
/* Get the bit index of the top most value */
bit_index = BIT_INDEX (n_bits - 1);
/* Grow the array if necessary. This will clear the new data */
if (array_index >= array->len)
g_array_set_size (array, array_index + 1);
if (value)
{
/* Set the bits that are touching this index */
g_array_index (array, unsigned long, array_index) |=
~0UL >> (sizeof (unsigned long) * 8 - 1 - bit_index);
/* Set all of the bits in any lesser indices */
memset (array->data, 0xff, sizeof (unsigned long) * array_index);
}
else
{
/* Clear the bits that are touching this index */
g_array_index (array, unsigned long, array_index) &= ~1UL << bit_index;
/* Clear all of the bits in any lesser indices */
memset (array->data, 0x00, sizeof (unsigned long) * array_index);
}
}
void
_cogl_bitmask_xor_bits (CoglBitmask *dst,
const CoglBitmask *src)
{
if (_cogl_bitmask_has_array (src))
{
GArray *src_array, *dst_array;
int i;
if (!_cogl_bitmask_has_array (dst))
_cogl_bitmask_convert_to_array (dst);
dst_array = (GArray *) *dst;
src_array = (GArray *) *src;
if (dst_array->len < src_array->len)
g_array_set_size (dst_array, src_array->len);
for (i = 0; i < src_array->len; i++)
g_array_index (dst_array, unsigned long, i) ^=
g_array_index (src_array, unsigned long, i);
}
else if (_cogl_bitmask_has_array (dst))
{
GArray *dst_array;
dst_array = (GArray *) *dst;
g_array_index (dst_array, unsigned long, 0) ^=
_cogl_bitmask_to_bits (src);
}
else
*dst = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (dst) ^
_cogl_bitmask_to_bits (src));
}
void
_cogl_bitmask_clear_all_in_array (CoglBitmask *bitmask)
{
GArray *array = (GArray *) *bitmask;
memset (array->data, 0, sizeof (unsigned long) * array->len);
}
void
_cogl_bitmask_foreach (const CoglBitmask *bitmask,
CoglBitmaskForeachFunc func,
void *user_data)
{
if (_cogl_bitmask_has_array (bitmask))
{
GArray *array = (GArray *) *bitmask;
const unsigned long *values = &g_array_index (array, unsigned long, 0);
int bit_num;
COGL_FLAGS_FOREACH_START (values, array->len, bit_num)
{
if (!func (bit_num, user_data))
return;
}
COGL_FLAGS_FOREACH_END;
}
else
{
unsigned long mask = _cogl_bitmask_to_bits (bitmask);
int bit_num;
COGL_FLAGS_FOREACH_START (&mask, 1, bit_num)
{
if (!func (bit_num, user_data))
return;
}
COGL_FLAGS_FOREACH_END;
}
}
void
_cogl_bitmask_set_flags_array (const CoglBitmask *bitmask,
unsigned long *flags)
{
const GArray *array = (const GArray *) *bitmask;
int i;
for (i = 0; i < array->len; i++)
flags[i] |= g_array_index (array, unsigned long, i);
}
int
_cogl_bitmask_popcount_in_array (const CoglBitmask *bitmask)
{
const GArray *array = (const GArray *) *bitmask;
int pop = 0;
int i;
for (i = 0; i < array->len; i++)
pop += _cogl_util_popcountl (g_array_index (array, unsigned long, i));
return pop;
}
int
_cogl_bitmask_popcount_upto_in_array (const CoglBitmask *bitmask,
int upto)
{
const GArray *array = (const GArray *) *bitmask;
if (upto >= array->len * sizeof (unsigned long) * 8)
return _cogl_bitmask_popcount_in_array (bitmask);
else
{
unsigned long top_mask;
int array_index = ARRAY_INDEX (upto);
int bit_index = BIT_INDEX (upto);
int pop = 0;
int i;
for (i = 0; i < array_index; i++)
pop += _cogl_util_popcountl (g_array_index (array, unsigned long, i));
top_mask = g_array_index (array, unsigned long, array_index);
return pop + _cogl_util_popcountl (top_mask & ((1UL << bit_index) - 1));
}
}