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