hack/hack.rumors.c

   1 /*
   2  * Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985.
   3  */
   4
   5 #ifndef lint
   6 static char rcsid[] = "$Id: hack.rumors.c,v 1.2 1993/08/02 17:19:20 mycroft Exp $";
   7 #endif /* not lint */
   8
   9 #include        <stdio.h>
  10 #include        "hack.h"                /* for RUMORFILE and BSD (index) */
  11 #define CHARSZ  8                       /* number of bits in a char */
  12 extern long *alloc();
  13 extern char *index();
  14 int n_rumors = 0;
  15 int n_used_rumors = -1;
  16 char *usedbits;
  17
  18 init_rumors(rumf) register FILE *rumf; {
  19 register int i;
  20         n_used_rumors = 0;
  21         while(skipline(rumf)) n_rumors++;
  22         rewind(rumf);
  23         i = n_rumors/CHARSZ;
  24         usedbits = (char *) alloc((unsigned)(i+1));
  25         for( ; i>=0; i--) usedbits[i] = 0;
  26 }
  27
  28 skipline(rumf) register FILE *rumf; {
  29 char line[COLNO];
  30         while(1) {
  31                 if(!fgets(line, sizeof(line), rumf)) return(0);
  32                 if(index(line, '\n')) return(1);
  33         }
  34 }
  35
  36 outline(rumf) register FILE *rumf; {
  37 char line[COLNO];
  38 register char *ep;
  39         if(!fgets(line, sizeof(line), rumf)) return;
  40         if((ep = index(line, '\n')) != 0) *ep = 0;
  41         pline("This cookie has a scrap of paper inside! It reads: ");
  42         pline(line);
  43 }
  44
  45 outrumor(){
  46 register int rn,i;
  47 register FILE *rumf;
  48         if(n_rumors <= n_used_rumors ||
  49           (rumf = fopen(RUMORFILE, "r")) == (FILE *) 0) return;
  50         if(n_used_rumors < 0) init_rumors(rumf);
  51         if(!n_rumors) goto none;
  52         rn = rn2(n_rumors - n_used_rumors);
  53         i = 0;
  54         while(rn || used(i)) {
  55                 (void) skipline(rumf);
  56                 if(!used(i)) rn--;
  57                 i++;
  58         }
  59         usedbits[i/CHARSZ] |= (1 << (i % CHARSZ));
  60         n_used_rumors++;
  61         outline(rumf);
  62 none:
  63         (void) fclose(rumf);
  64 }
  65
  66 used(i) register int i; {
  67         return(usedbits[i/CHARSZ] & (1 << (i % CHARSZ)));
  68 }