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#
# 6. Products derived from this software may not be called "RDFStore"
#    nor may "RDFStore" appear in their names without prior written
#    permission.
#
# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
# OF THE POSSIBILITY OF SUCH DAMAGE.
#
# ====================================================================
#
# This software consists of work developed by Alberto Reggiori and 
# Dirk-Willem van Gulik. The RDF specific part is based based on public 
# domain software written at the Stanford University Database Group by 
# Sergey Melnik. For more information on the RDF API Draft work, 
# please see <http://www-db.stanford.edu/~melnik/rdf/api.html>
# The DBMS TCP/IP server part is based on software originally written
# by Dirk-Willem van Gulik for Web Weaving Internet Engineering m/v Enschede,
# The Netherlands.
#
##############################################################################

 $Id: rdfstore_bits.c,v 1.16 2006/06/19 10:10:21 areggiori Exp $
*/

#include <sys/types.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>

#include "dbms.h"
#include "dbms_compat.h"

#include "rdfstore.h"
#include "rdfstore_bits.h"
#include "rdfstore_log.h"

/* within p->size / p->bits
 * set at -bit- position 'at' 
 * the masked bits to value
 *
 * return the modified bits
 */

/*
 * #define RDFSTORE_DEBUG_BITS
 */

int rdfstore_bits_setmask( 
	unsigned int * size,
	unsigned char * bits,
	unsigned int at, 
	unsigned int mask,
	unsigned int value,
	unsigned int max
) {
	register int depth,change;

	if (mask == 0) return(0);

	/* auto extend if needed... */
	if ( (at/8) >= *size) {
		unsigned int n=*size;
		unsigned int s= STEP * ( 1 + at/8/STEP );
		if (s>max) {
			fprintf(stderr, "Too many bit=%d byte=%d %d of %d\n",
				at, at/8, s, max);
			exit(1);
			};
		*size = s;
		bzero(bits+n, s-n);
		};

	/*	x x x x x x as stored
	 *	0 0 1 1 1 0 mask
  	 *	0 0 0 1 1 0 value
	 */
	mask <<= at % 8;	
	value <<= at % 8;
	at /= 8;
	change =0; depth = 0;
	do {
		register unsigned char d,c;
		if (at>=max) {
			fprintf(stderr,"Uncontrolled overflow %d of %d\n",
				at, max);
			exit(1);
			};

		c = bits[ at ];
		d = ( c & (~ mask) ) | value;

		if (d != c) {
			bits[ at ] = d;
			change |= (d ^ c) << depth; 
			};
		at ++;

		depth += 8;
		mask >>= 8;
		value >>= 8;

		} while ((mask) && (at < *size ));

	return (change);
	};

/* Return the record number (bit number / 4) of the
 * first record from record 'at' onwards which has