lib-src/yow.c

   1 /*
   2  * yow.c
   3  *
   4  * Print a quotation from Zippy the Pinhead.
   5  * Qux <Kaufman-David@Yale> March 6, 1986
   6  *
   7  * This file is in the public domain because the author published it
   8  * with no copyright notice before the US signed the Bern Convention.
   9  *
  10  * With dynamic memory allocation.
  11  */
  12
  13 #include <stdio.h>
  14 #include <ctype.h>
  15 #include <../src/epaths.h>      /* For PATH_DATA.  */
  16
  17 #define BUFSIZE  80
  18 #define SEP      '\0'
  19
  20 #ifndef YOW_FILE
  21 #define YOW_FILE "yow.lines"
  22 #endif
  23
  24 #ifdef MSDOS
  25 #define rootrelativepath(rel) \
  26 ({\
  27     static char res[BUFSIZE], *p;\
  28     strcpy (res, argv[0]);\
  29     p = res + strlen (res);\
  30     while (p != res && *p != '/' && *p != '\\' && *p != ':') p--;\
  31     strcpy (p + 1, "../");\
  32     strcpy (p + 4, rel);\
  33     &res;})
  34 #endif
  35
  36 char *malloc(), *realloc();
  37
  38 void yow();
  39 void setup_yow();
  40
  41 int
  42 main (argc, argv)
  43      int argc;
  44      char *argv[];
  45 {
  46   FILE *fp;
  47   char file[BUFSIZ];
  48
  49   if (argc > 2 && !strcmp (argv[1], "-f"))
  50     strcpy (file, argv[2]);
  51   else
  52 #ifdef vms
  53     sprintf (file, "%s%s", PATH_DATA, YOW_FILE);
  54 #else
  55     sprintf (file, "%s/%s", PATH_DATA, YOW_FILE);
  56 #endif
  57
  58   if ((fp = fopen(file, "r")) == NULL) {
  59     fprintf(stderr, "yow: ");
  60     perror(file);
  61     exit(1);
  62   }
  63
  64   /* initialize random seed */
  65   srand((int) (getpid() + time((long *) 0)));
  66
  67   setup_yow(fp);
  68   yow(fp);
  69   fclose(fp);
  70   return 0;
  71 }
  72
  73 static long len = -1;
  74 static long header_len;
  75
  76 #define AVG_LEN 40              /* average length of a quotation */
  77
  78 /* Sets len and header_len */
  79 void
  80 setup_yow(fp)
  81      FILE *fp;
  82 {
  83   int c;
  84
  85   /* Get length of file */
  86   /* Because the header (stuff before the first SEP) can be very long,
  87    * thus biasing our search in favor of the first quotation in the file,
  88    * we explicitly skip that. */
  89   while ((c = getc(fp)) != SEP) {
  90     if (c == EOF) {
  91       fprintf(stderr, "yow: file contains no separators\n");
  92       exit(2);
  93     }
  94   }
  95   header_len = ftell(fp);
  96   if (header_len > AVG_LEN)
  97     header_len -= AVG_LEN;      /* allow the first quotation to appear */
  98
  99   if (fseek(fp, 0L, 2) == -1) {
 100     perror("yow");
 101     exit(1);
 102   }
 103   len = ftell(fp) - header_len;
 104 }
 105
 106
 107 /* go to a random place in the file and print the quotation there */
 108 void
 109 yow (fp)
 110      FILE *fp;
 111 {
 112   long offset;
 113   int c, i = 0;
 114   char *buf;
 115   unsigned int bufsize;
 116
 117   offset = rand() % len + header_len;
 118   if (fseek(fp, offset, 0) == -1) {
 119     perror("yow");
 120     exit(1);
 121   }
 122
 123   /* Read until SEP, read next line, print it.
 124      (Note that we will never print anything before the first separator.)
 125      If we hit EOF looking for the first SEP, just recurse. */
 126   while ((c = getc(fp)) != SEP)
 127     if (c == EOF) {
 128       yow(fp);
 129       return;
 130     }
 131
 132   /* Skip leading whitespace, then read in a quotation.
 133      If we hit EOF before we find a non-whitespace char, recurse. */
 134   while (isspace(c = getc(fp)))
 135     ;
 136   if (c == EOF) {
 137     yow(fp);
 138     return;
 139   }
 140
 141   bufsize = BUFSIZE;
 142   buf = malloc(bufsize);
 143   if (buf == (char *)0) {
 144     fprintf(stderr, "yow: virtual memory exhausted\n");
 145     exit (3);
 146   }
 147
 148   buf[i++] = c;
 149   while ((c = getc(fp)) != SEP && c != EOF) {
 150     buf[i++] = c;
 151
 152     if (i == bufsize-1) {
 153       /* Yow! Is this quotation too long yet? */
 154       bufsize *= 2;
 155       buf = realloc(buf, bufsize);
 156       if (buf == (char *)0) {
 157         fprintf(stderr, "yow: virtual memory exhausted\n");
 158         exit (3);
 159       }
 160     }
 161   }
 162   buf[i++] = 0;
 163   printf("%s\n", buf);
 164 }
 165