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      1 /*	$NetBSD: hack.rumors.c,v 1.9 2011/08/06 20:18:26 dholland Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1985, Stichting Centrum voor Wiskunde en Informatica,
      5  * Amsterdam
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions are
     10  * met:
     11  *
     12  * - Redistributions of source code must retain the above copyright notice,
     13  * this list of conditions and the following disclaimer.
     14  *
     15  * - Redistributions in binary form must reproduce the above copyright
     16  * notice, this list of conditions and the following disclaimer in the
     17  * documentation and/or other materials provided with the distribution.
     18  *
     19  * - Neither the name of the Stichting Centrum voor Wiskunde en
     20  * Informatica, nor the names of its contributors may be used to endorse or
     21  * promote products derived from this software without specific prior
     22  * written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
     25  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     27  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
     28  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     29  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     31  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     33  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     34  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     35  */
     36 
     37 /*
     38  * Copyright (c) 1982 Jay Fenlason <hack (at) gnu.org>
     39  * All rights reserved.
     40  *
     41  * Redistribution and use in source and binary forms, with or without
     42  * modification, are permitted provided that the following conditions
     43  * are met:
     44  * 1. Redistributions of source code must retain the above copyright
     45  *    notice, this list of conditions and the following disclaimer.
     46  * 2. Redistributions in binary form must reproduce the above copyright
     47  *    notice, this list of conditions and the following disclaimer in the
     48  *    documentation and/or other materials provided with the distribution.
     49  * 3. The name of the author may not be used to endorse or promote products
     50  *    derived from this software without specific prior written permission.
     51  *
     52  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
     53  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
     54  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
     55  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     56  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     57  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     58  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     59  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     60  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     61  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     62  */
     63 
     64 #include <sys/cdefs.h>
     65 #ifndef lint
     66 __RCSID("$NetBSD: hack.rumors.c,v 1.9 2011/08/06 20:18:26 dholland Exp $");
     67 #endif				/* not lint */
     68 
     69 #include "hack.h"	/* for RUMORFILE and BSD (strchr) */
     70 #include "extern.h"
     71 #define	CHARSZ	8		/* number of bits in a char */
     72 
     73 static int n_rumors = 0;
     74 static int n_used_rumors = -1;
     75 static char *usedbits;
     76 
     77 static void init_rumors(FILE *);
     78 static int skipline(FILE *);
     79 static void outline(FILE *);
     80 static int used(int);
     81 
     82 static void
     83 init_rumors(FILE *rumf)
     84 {
     85 	int             i;
     86 	n_used_rumors = 0;
     87 	while (skipline(rumf))
     88 		n_rumors++;
     89 	rewind(rumf);
     90 	i = n_rumors / CHARSZ;
     91 	usedbits = alloc(i + 1);
     92 	for (; i >= 0; i--)
     93 		usedbits[i] = 0;
     94 }
     95 
     96 static int
     97 skipline(FILE *rumf)
     98 {
     99 	char            line[COLNO];
    100 	while (1) {
    101 		if (!fgets(line, sizeof(line), rumf))
    102 			return (0);
    103 		if (strchr(line, '\n'))
    104 			return (1);
    105 	}
    106 }
    107 
    108 static void
    109 outline(FILE *rumf)
    110 {
    111 	char            line[COLNO];
    112 	char           *ep;
    113 	if (!fgets(line, sizeof(line), rumf))
    114 		return;
    115 	if ((ep = strchr(line, '\n')) != 0)
    116 		*ep = 0;
    117 	pline("This cookie has a scrap of paper inside! It reads: ");
    118 	pline("%s", line);
    119 }
    120 
    121 void
    122 outrumor(void)
    123 {
    124 	int             rn, i;
    125 	FILE           *rumf;
    126 	if (n_rumors <= n_used_rumors ||
    127 	    (rumf = fopen(RUMORFILE, "r")) == (FILE *) 0)
    128 		return;
    129 	if (n_used_rumors < 0)
    130 		init_rumors(rumf);
    131 	if (!n_rumors)
    132 		goto none;
    133 	rn = rn2(n_rumors - n_used_rumors);
    134 	i = 0;
    135 	while (rn || used(i)) {
    136 		(void) skipline(rumf);
    137 		if (!used(i))
    138 			rn--;
    139 		i++;
    140 	}
    141 	usedbits[i / CHARSZ] |= (1 << (i % CHARSZ));
    142 	n_used_rumors++;
    143 	outline(rumf);
    144 none:
    145 	(void) fclose(rumf);
    146 }
    147 
    148 static int
    149 used(int i)
    150 {
    151 	return (usedbits[i / CHARSZ] & (1 << (i % CHARSZ)));
    152 }
    153