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      1 /*	$NetBSD: cur_hash.c,v 1.14 2021/09/07 01:23:09 rin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)cur_hash.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: cur_hash.c,v 1.14 2021/09/07 01:23:09 rin Exp $");
     38 #endif
     39 #endif				/* not lint */
     40 
     41 #include <sys/types.h>
     42 
     43 #include "curses.h"
     44 #include "curses_private.h"
     45 
     46 /*
     47  * __hash_more() is "hashpjw" from the Dragon Book, Aho, Sethi & Ullman, p.436.
     48  */
     49 unsigned int
     50 __hash_more(const void  *v_s, size_t len, unsigned int h)
     51 {
     52 	unsigned int g;
     53 	size_t i = 0;
     54 	const char *s = v_s;
     55 
     56 	while (i < len) {
     57 		h = (h << 4) + s[i];
     58 		if ((g = h & 0xf0000000) != 0) {
     59 			h = h ^ (g >> 24);
     60 			h = h ^ g;
     61 		}
     62 		i++;
     63 	}
     64 	return h;
     65 }
     66 
     67 unsigned int
     68 __hash_line(const __LDATA *cp, int ncols)
     69 {
     70 #ifdef HAVE_WCHAR
     71 	unsigned int h;
     72 	const nschar_t *np;
     73 	int x;
     74 
     75 	h = 0;
     76 	for (x = 0; x < ncols; x++) {
     77 		h = __hash_more(&cp->ch, sizeof(cp->ch), h);
     78 		h = __hash_more(&cp->attr, sizeof(cp->attr), h);
     79 		for (np = cp->nsp; np != NULL; np = np->next)
     80 			h = __hash_more(&np->ch, sizeof(np->ch), h);
     81 		cp++;
     82 	}
     83 	return h;
     84 #else
     85 	return __hash(cp, (size_t)(ncols * __LDATASIZE));
     86 #endif
     87 }
     88