f23b12a886
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>
308 lines
9.3 KiB
C
308 lines
9.3 KiB
C
/*
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* Cogl
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*
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* An object oriented GL/GLES Abstraction/Utility Layer
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*
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* Copyright (C) 2010 Intel Corporation.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Authors:
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* Neil Roberts <neil@linux.intel.com>
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*/
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#ifndef __COGL_BITMASK_H
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#define __COGL_BITMASK_H
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#include <glib.h>
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#include "cogl-util.h"
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G_BEGIN_DECLS
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/*
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* CoglBitmask implements a growable array of bits. A CoglBitmask can
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* be allocated on the stack but it must be initialised with
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* _cogl_bitmask_init() before use and then destroyed with
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* _cogl_bitmask_destroy(). A CoglBitmask will try to avoid allocating
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* any memory unless more than the number of bits in a long - 1 bits
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* are needed.
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*
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* Internally a CoglBitmask is a pointer. If the least significant bit
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* of the pointer is 1 then the rest of the bits are directly used as
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* part of the bitmask, otherwise it is a pointer to a GArray of
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* unsigned ints. This relies on the fact the g_malloc will return a
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* pointer aligned to at least two bytes (so that the least
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* significant bit of the address is always 0). It also assumes that
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* the size of a pointer is always greater than or equal to the size
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* of a long (although there is a compile time assert to verify this).
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*
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* If the maximum possible bit number in the set is known at compile
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* time, it may make more sense to use the macros in cogl-flags.h
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* instead of this type.
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*/
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typedef struct _CoglBitmaskImaginaryType *CoglBitmask;
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/* These are internal helper macros */
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#define _cogl_bitmask_to_number(bitmask) \
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((unsigned long) (*bitmask))
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#define _cogl_bitmask_to_bits(bitmask) \
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(_cogl_bitmask_to_number (bitmask) >> 1UL)
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/* The least significant bit is set to mark that no array has been
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allocated yet */
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#define _cogl_bitmask_from_bits(bits) \
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((void *) ((((unsigned long) (bits)) << 1UL) | 1UL))
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/* Internal helper macro to determine whether this bitmask has a
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GArray allocated or whether the pointer is just used directly */
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#define _cogl_bitmask_has_array(bitmask) \
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(!(_cogl_bitmask_to_number (bitmask) & 1UL))
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/* Number of bits we can use before needing to allocate an array */
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#define COGL_BITMASK_MAX_DIRECT_BITS (sizeof (unsigned long) * 8 - 1)
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/*
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* _cogl_bitmask_init:
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* @bitmask: A pointer to a bitmask
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*
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* Initialises the cogl bitmask. This must be called before any other
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* bitmask functions are called. Initially all of the values are
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* zero
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*/
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#define _cogl_bitmask_init(bitmask) \
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G_STMT_START { *(bitmask) = _cogl_bitmask_from_bits (0); } G_STMT_END
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gboolean
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_cogl_bitmask_get_from_array (const CoglBitmask *bitmask,
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unsigned int bit_num);
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void
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_cogl_bitmask_set_in_array (CoglBitmask *bitmask,
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unsigned int bit_num,
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gboolean value);
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void
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_cogl_bitmask_set_range_in_array (CoglBitmask *bitmask,
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unsigned int n_bits,
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gboolean value);
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void
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_cogl_bitmask_clear_all_in_array (CoglBitmask *bitmask);
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void
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_cogl_bitmask_set_flags_array (const CoglBitmask *bitmask,
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unsigned long *flags);
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int
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_cogl_bitmask_popcount_in_array (const CoglBitmask *bitmask);
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int
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_cogl_bitmask_popcount_upto_in_array (const CoglBitmask *bitmask,
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int upto);
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/*
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* cogl_bitmask_set_bits:
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* @dst: The bitmask to modify
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* @src: The bitmask to copy bits from
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*
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* This makes sure that all of the bits that are set in @src are also
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* set in @dst. Any unset bits in @src are left alone in @dst.
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*/
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void
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_cogl_bitmask_set_bits (CoglBitmask *dst,
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const CoglBitmask *src);
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/*
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* cogl_bitmask_xor_bits:
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* @dst: The bitmask to modify
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* @src: The bitmask to copy bits from
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*
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* For every bit that is set in src, the corresponding bit in dst is
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* inverted.
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*/
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void
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_cogl_bitmask_xor_bits (CoglBitmask *dst,
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const CoglBitmask *src);
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/* The foreach function can return FALSE to stop iteration */
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typedef gboolean (* CoglBitmaskForeachFunc) (int bit_num, void *user_data);
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/*
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* cogl_bitmask_foreach:
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* @bitmask: A pointer to a bitmask
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* @func: A callback function
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* @user_data: A pointer to pass to the callback
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*
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* This calls @func for each bit that is set in @bitmask.
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*/
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void
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_cogl_bitmask_foreach (const CoglBitmask *bitmask,
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CoglBitmaskForeachFunc func,
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void *user_data);
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/*
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* _cogl_bitmask_get:
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* @bitmask: A pointer to a bitmask
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* @bit_num: A bit number
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*
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* Return value: whether bit number @bit_num is set in @bitmask
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*/
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static inline gboolean
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_cogl_bitmask_get (const CoglBitmask *bitmask, unsigned int bit_num)
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{
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if (_cogl_bitmask_has_array (bitmask))
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return _cogl_bitmask_get_from_array (bitmask, bit_num);
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else if (bit_num >= COGL_BITMASK_MAX_DIRECT_BITS)
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return FALSE;
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else
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return !!(_cogl_bitmask_to_bits (bitmask) & (1UL << bit_num));
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}
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/*
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* _cogl_bitmask_set:
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* @bitmask: A pointer to a bitmask
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* @bit_num: A bit number
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* @value: The new value
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*
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* Sets or resets a bit number @bit_num in @bitmask according to @value.
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*/
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static inline void
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_cogl_bitmask_set (CoglBitmask *bitmask, unsigned int bit_num, gboolean value)
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{
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if (_cogl_bitmask_has_array (bitmask) ||
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bit_num >= COGL_BITMASK_MAX_DIRECT_BITS)
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_cogl_bitmask_set_in_array (bitmask, bit_num, value);
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else if (value)
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*bitmask = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (bitmask) |
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(1UL << bit_num));
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else
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*bitmask = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (bitmask) &
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~(1UL << bit_num));
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}
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/*
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* _cogl_bitmask_set_range:
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* @bitmask: A pointer to a bitmask
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* @n_bits: The number of bits to set
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* @value: The value to set
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*
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* Sets the first @n_bits in @bitmask to @value.
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*/
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static inline void
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_cogl_bitmask_set_range (CoglBitmask *bitmask,
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unsigned int n_bits,
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gboolean value)
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{
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if (_cogl_bitmask_has_array (bitmask) ||
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n_bits > COGL_BITMASK_MAX_DIRECT_BITS)
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_cogl_bitmask_set_range_in_array (bitmask, n_bits, value);
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else if (value)
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*bitmask = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (bitmask) |
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~(~0UL << n_bits));
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else
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*bitmask = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (bitmask) &
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(~0UL << n_bits));
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}
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/*
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* _cogl_bitmask_destroy:
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* @bitmask: A pointer to a bitmask
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*
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* Destroys any resources allocated by the bitmask
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*/
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static inline void
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_cogl_bitmask_destroy (CoglBitmask *bitmask)
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{
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if (_cogl_bitmask_has_array (bitmask))
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g_array_free ((GArray *) *bitmask, TRUE);
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}
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/*
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* _cogl_bitmask_clear_all:
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* @bitmask: A pointer to a bitmask
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*
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* Clears all the bits in a bitmask without destroying any resources.
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*/
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static inline void
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_cogl_bitmask_clear_all (CoglBitmask *bitmask)
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{
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if (_cogl_bitmask_has_array (bitmask))
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_cogl_bitmask_clear_all_in_array (bitmask);
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else
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*bitmask = _cogl_bitmask_from_bits (0);
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}
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/*
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* _cogl_bitmask_set_flags:
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* @bitmask: A pointer to a bitmask
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* @flags: An array of flags
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*
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* Bitwise or's the bits from @bitmask into the flags array (see
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* cogl-flags) pointed to by @flags.
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*/
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static inline void
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_cogl_bitmask_set_flags (const CoglBitmask *bitmask,
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unsigned long *flags)
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{
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if (_cogl_bitmask_has_array (bitmask))
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return _cogl_bitmask_set_flags_array (bitmask, flags);
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else
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flags[0] |= _cogl_bitmask_to_bits (bitmask);
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}
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/*
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* _cogl_bitmask_popcount:
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* @bitmask: A pointer to a bitmask
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*
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* Counts the number of bits that are set in the bitmask.
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*
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* Return value: the number of bits set in @bitmask.
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*/
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static inline int
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_cogl_bitmask_popcount (const CoglBitmask *bitmask)
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{
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return (_cogl_bitmask_has_array (bitmask) ?
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_cogl_bitmask_popcount_in_array (bitmask) :
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_cogl_util_popcountl (_cogl_bitmask_to_bits (bitmask)));
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}
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/*
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* _cogl_bitmask_popcount:
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* @Bitmask: A pointer to a bitmask
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* @upto: The maximum bit index to consider
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*
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* Counts the number of bits that are set and have an index which is
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* less than @upto.
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*
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* Return value: the number of bits set in @bitmask that are less than @upto.
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*/
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static inline int
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_cogl_bitmask_popcount_upto (const CoglBitmask *bitmask,
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int upto)
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{
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if (_cogl_bitmask_has_array (bitmask))
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return _cogl_bitmask_popcount_upto_in_array (bitmask, upto);
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else if (upto >= COGL_BITMASK_MAX_DIRECT_BITS)
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return _cogl_util_popcountl (_cogl_bitmask_to_bits (bitmask));
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else
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return _cogl_util_popcountl (_cogl_bitmask_to_bits (bitmask) &
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((1UL << upto) - 1));
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}
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G_END_DECLS
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#endif /* __COGL_BITMASK_H */
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