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/******************************************************************************
*
* Project: MapServer
* Purpose: Implementation of bit array functions.
* Author: Steve Lime and the MapServer team.
*
******************************************************************************
* Copyright (c) 1996-2005 Regents of the University of Minnesota.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies of this Software or works derived from this Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
******************************************************************************
*
* $Log: mapbits.c,v $
* Revision 1.3 2005/06/14 16:03:33 dan
* Updated copyright date to 2005
*
* Revision 1.2 2004/10/21 04:30:55 frank
* Added standardized headers. Added MS_CVSID().
*
*/
#include "map.h"
MS_CVSID("$Id: mapbits.c,v 1.3 2005/06/14 16:03:33 dan Exp $")
#include <limits.h>
/* originally found at http://www.snippets.org/ */
size_t msGetBitArraySize(int numbits)
{
return((numbits + CHAR_BIT - 1) / CHAR_BIT);
}
char *msAllocBitArray(int numbits)
{
char *array = calloc((numbits + CHAR_BIT - 1) / CHAR_BIT, sizeof(char));
return(array);
}
int msGetBit(char *array, int index)
{
array += index / CHAR_BIT;
return (*array & (1 << (index % CHAR_BIT))) != 0; /* 0 or 1 */
}
void msSetBit(char *array, int index, int value)
{
array += index / CHAR_BIT;
if (value)
*array |= 1 << (index % CHAR_BIT); /* set bit */
else
*array &= ~(1 << (index % CHAR_BIT)); /* clear bit */
}
void msFlipBit(char *array, int index)
{
array += index / CHAR_BIT;
*array ^= 1 << (index % CHAR_BIT); /* flip bit */
}
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