cogl: Add an internal CoglBitmask type

This implements a growable array of bits called CoglBitmask. The
CoglBitmask is intended to be cheap if less than 32 bits are used. If
more bits are required it will allocate a GArray. The type is meant to
be allocated on the stack but because it can require additional
resources it also has a destroy function.

http://bugzilla.openedhand.com/show_bug.cgi?id=2132
This commit is contained in:
Neil Roberts 2010-05-20 17:31:42 +01:00
parent 52cbc93b18
commit 4fb784d111
3 changed files with 482 additions and 0 deletions

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@ -137,6 +137,8 @@ cogl_sources_c = \
$(srcdir)/cogl-matrix-mesa.c \
$(srcdir)/cogl-profile.h \
$(srcdir)/cogl-profile.c \
$(srcdir)/cogl-bitmask.h \
$(srcdir)/cogl-bitmask.c \
$(NULL)
# glib-mkenums rules

257
cogl/cogl-bitmask.c Normal file
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@ -0,0 +1,257 @@
/*
* 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"
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 int) * 8 * array->len)
return FALSE;
else
return !!(g_array_index (array, unsigned int,
bit_num / (sizeof (unsigned int) * 8)) &
(1 << (bit_num % (sizeof (unsigned int) * 8))));
}
static void
_cogl_bitmask_convert_to_array (CoglBitmask *bitmask)
{
GArray *array;
/* Fetch the old values, ignoring the least significant bit */
unsigned int old_values = GPOINTER_TO_UINT (*bitmask) >> 1;
array = g_array_new (FALSE, TRUE, sizeof (unsigned int));
/* 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, 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 = bit_num / (sizeof (unsigned int) * 8);
/* 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 = 1 << (bit_num % (sizeof (unsigned int) * 8));
if (value)
g_array_index (array, unsigned int, array_index) |= new_value_mask;
else
g_array_index (array, unsigned int, 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 int, i) |=
g_array_index (src_array, unsigned int, i);
}
else if (_cogl_bitmask_has_array (dst))
{
GArray *dst_array;
dst_array = (GArray *) *dst;
g_array_index (dst_array, unsigned int, 0) |=
(GPOINTER_TO_UINT (*src) >> 1);
}
else
*dst = GUINT_TO_POINTER (GPOINTER_TO_UINT (*dst) |
GPOINTER_TO_UINT (*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 = (n_bits - 1) / (sizeof (unsigned int) * 8);
/* Get the bit index of the top most value */
bit_index = (n_bits - 1) % (sizeof (unsigned int) * 8);
/* 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 int, array_index) |=
~(unsigned int) 0 >> (sizeof (unsigned int) * 8 - 1 - bit_index);
/* Set all of the bits in any lesser indices */
memset (array->data, 0xff, sizeof (unsigned int) * array_index);
}
else
{
/* Clear the bits that are touching this index */
g_array_index (array, unsigned int, array_index) &=
~(unsigned int) 1 << bit_index;
/* Clear all of the bits in any lesser indices */
memset (array->data, 0x00, sizeof (unsigned int) * array_index);
}
}
void
_cogl_bitmask_clear_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 int, i) &=
~g_array_index (src_array, unsigned int, i);
}
else if (_cogl_bitmask_has_array (dst))
{
GArray *dst_array;
dst_array = (GArray *) *dst;
g_array_index (dst_array, unsigned int, 0) &=
~(GPOINTER_TO_UINT (*src) >> 1);
}
else
*dst = GUINT_TO_POINTER ((GPOINTER_TO_UINT (*dst) &
~GPOINTER_TO_UINT (*src)) | 1);
}
void
_cogl_bitmask_clear_all_in_array (CoglBitmask *bitmask)
{
GArray *array = (GArray *) *bitmask;
memset (array->data, 0, sizeof (unsigned int) * array->len);
}
void
_cogl_bitmask_foreach (const CoglBitmask *bitmask,
CoglBitmaskForeachFunc func,
gpointer user_data)
{
if (_cogl_bitmask_has_array (bitmask))
{
GArray *array = (GArray *) *bitmask;
int array_index;
for (array_index = 0; array_index < array->len; array_index++)
{
unsigned int mask = g_array_index (array, unsigned int, array_index);
int bit = 0;
while (mask)
{
if (mask & 1)
func (array_index * sizeof (unsigned int) * 8 + bit, user_data);
bit++;
mask >>= 1;
}
}
}
else
{
unsigned int mask = GPOINTER_TO_UINT (*bitmask) >> 1;
int bit = 0;
while (mask)
{
if (mask & 1)
func (bit, user_data);
bit++;
mask >>= 1;
}
}
}

223
cogl/cogl-bitmask.h Normal file
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@ -0,0 +1,223 @@
/*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Authors:
* Neil Roberts <neil@linux.intel.com>
*/
#ifndef __COGL_BITMASK_H
#define __COGL_BITMASK_H
#include <glib.h>
G_BEGIN_DECLS
/*
* CoglBitmask implements a growable array of bits. A CoglBitmask can
* be allocated on the stack but it must be initialised with
* _cogl_bitmask_init() before use and then destroyed with
* _cogl_bitmask_destroy(). A CoglBitmask will try to avoid allocating
* any memory unless more than 31 bits are needed.
*
* Internally a CoglBitmask is a pointer. If the least significant bit
* of the pointer is 1 then the rest of the bits are directly used as
* part of the bitmask, otherwise it is a pointer to a GArray of
* unsigned ints. This relies on the fact the g_malloc will return a
* pointer aligned to at least two bytes (so that the least
* significant bit of the address is always 0)
*/
typedef struct _CoglBitmaskImaginaryType *CoglBitmask;
/* Internal helper macro to determine whether this bitmask has a
GArray allocated or whether the pointer is just used directly */
#define _cogl_bitmask_has_array(bitmask) \
(!(GPOINTER_TO_UINT (*bitmask) & 1))
/* Number of bits we can use before needing to allocate an array */
#define COGL_BITMASK_MAX_DIRECT_BITS (sizeof (unsigned int) * 8 - 1)
/*
* _cogl_bitmask_init:
* @bitmask: A pointer to a bitmask
*
* Initialises the cogl bitmask. This must be called before any other
* bitmask functions are called. Initially all of the values are
* zero
*/
/* Set the last significant bit to mark that no array has been
allocated yet */
#define _cogl_bitmask_init(bitmask) \
G_STMT_START { *(bitmask) = GUINT_TO_POINTER (1); } G_STMT_END
gboolean
_cogl_bitmask_get_from_array (const CoglBitmask *bitmask,
unsigned int bit_num);
void
_cogl_bitmask_set_in_array (CoglBitmask *bitmask,
unsigned int bit_num,
gboolean value);
void
_cogl_bitmask_set_range_in_array (CoglBitmask *bitmask,
unsigned int n_bits,
gboolean value);
void
_cogl_bitmask_clear_all_in_array (CoglBitmask *bitmask);
/*
* cogl_bitmask_set_bits:
* @dst: The bitmask to modify
* @src: The bitmask to copy bits from
*
* This makes sure that all of the bits that are set in @src are also
* set in @dst. Any unset bits in @src are left alone in @dst.
*/
void
_cogl_bitmask_set_bits (CoglBitmask *dst,
const CoglBitmask *src);
/*
* cogl_bitmask_clear_bits:
* @dst: The bitmask to modify
* @src: The bitmask to copy bits from
*
* This makes sure that all of the bits that are set in @src are
* cleared in @dst. Any unset bits in @src are left alone in @dst.
*/
void
_cogl_bitmask_clear_bits (CoglBitmask *dst,
const CoglBitmask *src);
typedef void (* CoglBitmaskForeachFunc) (int bit_num, gpointer user_data);
/*
* cogl_bitmask_foreach:
* @bitmask: A pointer to a bitmask
* @func: A callback function
* @user_data: A pointer to pass to the callback
*
* This calls @func for each bit that is set in @bitmask.
*/
void
_cogl_bitmask_foreach (const CoglBitmask *bitmask,
CoglBitmaskForeachFunc func,
gpointer user_data);
/*
* _cogl_bitmask_get:
* @bitmask: A pointer to a bitmask
* @bit_num: A bit number
*
* Return value: whether bit number @bit_num is set in @bitmask
*/
static inline gboolean
_cogl_bitmask_get (const CoglBitmask *bitmask, unsigned int bit_num)
{
if (_cogl_bitmask_has_array (bitmask))
return _cogl_bitmask_get_from_array (bitmask, bit_num);
else if (bit_num >= COGL_BITMASK_MAX_DIRECT_BITS)
return FALSE;
else
return !!(GPOINTER_TO_UINT (*bitmask) & (1 << (bit_num + 1)));
}
/*
* _cogl_bitmask_set:
* @bitmask: A pointer to a bitmask
* @bit_num: A bit number
* @value: The new value
*
* Sets or resets a bit number @bit_num in @bitmask according to @value.
*/
static inline void
_cogl_bitmask_set (CoglBitmask *bitmask, unsigned int bit_num, gboolean value)
{
if (_cogl_bitmask_has_array (bitmask) ||
bit_num >= COGL_BITMASK_MAX_DIRECT_BITS)
_cogl_bitmask_set_in_array (bitmask, bit_num, value);
else if (value)
*bitmask = GUINT_TO_POINTER (GPOINTER_TO_UINT (*bitmask) |
(1 << (bit_num + 1)));
else
*bitmask = GUINT_TO_POINTER (GPOINTER_TO_UINT (*bitmask) &
~(1 << (bit_num + 1)));
}
/*
* _cogl_bitmask_set_range:
* @bitmask: A pointer to a bitmask
* @n_bits: The number of bits to set
* @value: The value to set
*
* Sets the first @n_bits in @bitmask to @value.
*/
static inline void
_cogl_bitmask_set_range (CoglBitmask *bitmask,
unsigned int n_bits,
gboolean value)
{
if (_cogl_bitmask_has_array (bitmask) ||
n_bits > COGL_BITMASK_MAX_DIRECT_BITS)
_cogl_bitmask_set_range_in_array (bitmask, n_bits, value);
else if (value)
*bitmask = GUINT_TO_POINTER (GPOINTER_TO_UINT (*bitmask) |
~(~(unsigned int) 1 << n_bits));
else
*bitmask = GUINT_TO_POINTER (GPOINTER_TO_UINT (*bitmask) &
((~(unsigned int) 1 << n_bits) | 1));
}
/*
* _cogl_bitmask_destroy:
* @bitmask: A pointer to a bitmask
*
* Destroys any resources allocated by the bitmask
*/
static inline void
_cogl_bitmask_destroy (CoglBitmask *bitmask)
{
if (_cogl_bitmask_has_array (bitmask))
g_array_free ((GArray *) *bitmask, TRUE);
}
/*
* _cogl_bitmask_clear_all:
* @bitmask: A pointer to a bitmask
*
* Clears all the bits in a bitmask without destroying any resources.
*/
static inline void
_cogl_bitmask_clear_all (CoglBitmask *bitmask)
{
if (_cogl_bitmask_has_array (bitmask))
_cogl_bitmask_clear_all_in_array (bitmask);
else
*bitmask = GUINT_TO_POINTER (1);
}
G_END_DECLS
#endif /* __COGL_BITMASK_H */