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  * With dynamic memory allocation.
   8  */
   9
  10 #include <stdio.h>
  11 #include <ctype.h>
  12 #include <../src/paths.h>      /* For PATH_DATA.  */
  13
  14 #define BUFSIZE  80
  15 #define SEP      '\0'
  16
  17 #ifndef YOW_FILE
  18 #define YOW_FILE "yow.lines"
  19 #endif
  20
  21 main (argc, argv)
  22      int argc;
  23      char *argv[];
  24 {
  25   FILE *fp;
  26   char file[BUFSIZ];
  27   void yow(), setup_yow();
  28
  29   if (argc > 2 && !strcmp (argv[1], "-f"))
  30     strcpy (file, argv[2]);
  31   else
  32 #ifdef vms
  33     sprintf (file, "%s%s", PATH_DATA, YOW_FILE);
  34 #else
  35     sprintf (file, "%s/%s", PATH_DATA, YOW_FILE);
  36 #endif
  37
  38   if ((fp = fopen(file, "r")) == NULL) {
  39     perror(file);
  40     exit(1);
  41   }
  42
  43   /* initialize random seed */
  44   srand((int) (getpid() + time((long *) 0)));
  45
  46   setup_yow(fp);
  47   yow(fp);
  48   fclose(fp);
  49   exit(0);
  50 }
  51
  52 static long len = -1;
  53 static long header_len;
  54
  55 #define AVG_LEN 40              /* average length of a quotation */
  56
  57 /* Sets len and header_len */
  58 void
  59 setup_yow(fp)
  60      FILE *fp;
  61 {
  62   int c;
  63
  64   /* Get length of file */
  65   /* Because the header (stuff before the first SEP) can be very long,
  66    * thus biasing our search in favor of the first quotation in the file,
  67    * we explicitly skip that. */
  68   while ((c = getc(fp)) != SEP) {
  69     if (c == EOF) {
  70       fprintf(stderr, "File contains no separators.\n");
  71       exit(2);
  72     }
  73   }
  74   header_len = ftell(fp);
  75   if (header_len > AVG_LEN)
  76     header_len -= AVG_LEN;      /* allow the first quotation to appear */
  77
  78   if (fseek(fp, 0L, 2) == -1) {
  79     perror("fseek 1");
  80     exit(1);
  81   }
  82   len = ftell(fp) - header_len;
  83 }
  84
  85
  86 /* go to a random place in the file and print the quotation there */
  87 void
  88 yow (fp)
  89      FILE *fp;
  90 {
  91   long offset;
  92   int c, i = 0;
  93   char *buf;
  94   unsigned int bufsize;
  95   char *malloc(), *realloc();
  96
  97   offset = rand() % len + header_len;
  98   if (fseek(fp, offset, 0) == -1) {
  99     perror("fseek 2");
 100     exit(1);
 101   }
 102
 103   /* Read until SEP, read next line, print it.
 104      (Note that we will never print anything before the first separator.)
 105      If we hit EOF looking for the first SEP, just recurse. */
 106   while ((c = getc(fp)) != SEP)
 107     if (c == EOF) {
 108       yow(fp);
 109       return;
 110     }
 111
 112   /* Skip leading whitespace, then read in a quotation.
 113      If we hit EOF before we find a non-whitespace char, recurse. */
 114   while (isspace(c = getc(fp)))
 115     ;
 116   if (c == EOF) {
 117     yow(fp);
 118     return;
 119   }
 120
 121   bufsize = BUFSIZE;
 122   buf = malloc(bufsize);
 123   if (buf == (char *)0) {
 124     fprintf(stderr, "can't allocate any memory\n");
 125     exit (3);
 126   }
 127
 128   buf[i++] = c;
 129   while ((c = getc(fp)) != SEP && c != EOF) {
 130     buf[i++] = c;
 131
 132     if (i == bufsize-1) {
 133       /* Yow! Is this quotation too long yet? */
 134       bufsize *= 2;
 135       buf = realloc(buf, bufsize);
 136       if (buf == (char *)0) {
 137         fprintf(stderr, "can't allocate more memory\n");
 138         exit (3);
 139       }
 140     }
 141   }
 142   buf[i++] = 0;
 143   printf("%s\n", buf);
 144 }
 145