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 main (argc, argv)
  34      int argc;
  35      char *argv[];
  36 {
  37   FILE *fp;
  38   char file[BUFSIZ];
  39   void yow(), setup_yow();
  40
  41   if (argc > 2 && !strcmp (argv[1], "-f"))
  42     strcpy (file, argv[2]);
  43   else
  44 #ifdef vms
  45     sprintf (file, "%s%s", PATH_DATA, YOW_FILE);
  46 #else
  47     sprintf (file, "%s/%s", PATH_DATA, YOW_FILE);
  48 #endif
  49
  50   if ((fp = fopen(file, "r")) == NULL) {
  51     perror(file);
  52     exit(1);
  53   }
  54
  55   /* initialize random seed */
  56   srand((int) (getpid() + time((long *) 0)));
  57
  58   setup_yow(fp);
  59   yow(fp);
  60   fclose(fp);
  61   exit(0);
  62 }
  63
  64 static long len = -1;
  65 static long header_len;
  66
  67 #define AVG_LEN 40              /* average length of a quotation */
  68
  69 /* Sets len and header_len */
  70 void
  71 setup_yow(fp)
  72      FILE *fp;
  73 {
  74   int c;
  75
  76   /* Get length of file */
  77   /* Because the header (stuff before the first SEP) can be very long,
  78    * thus biasing our search in favor of the first quotation in the file,
  79    * we explicitly skip that. */
  80   while ((c = getc(fp)) != SEP) {
  81     if (c == EOF) {
  82       fprintf(stderr, "File contains no separators.\n");
  83       exit(2);
  84     }
  85   }
  86   header_len = ftell(fp);
  87   if (header_len > AVG_LEN)
  88     header_len -= AVG_LEN;      /* allow the first quotation to appear */
  89
  90   if (fseek(fp, 0L, 2) == -1) {
  91     perror("fseek 1");
  92     exit(1);
  93   }
  94   len = ftell(fp) - header_len;
  95 }
  96
  97
  98 /* go to a random place in the file and print the quotation there */
  99 void
 100 yow (fp)
 101      FILE *fp;
 102 {
 103   long offset;
 104   int c, i = 0;
 105   char *buf;
 106   unsigned int bufsize;
 107   char *malloc(), *realloc();
 108
 109   offset = rand() % len + header_len;
 110   if (fseek(fp, offset, 0) == -1) {
 111     perror("fseek 2");
 112     exit(1);
 113   }
 114
 115   /* Read until SEP, read next line, print it.
 116      (Note that we will never print anything before the first separator.)
 117      If we hit EOF looking for the first SEP, just recurse. */
 118   while ((c = getc(fp)) != SEP)
 119     if (c == EOF) {
 120       yow(fp);
 121       return;
 122     }
 123
 124   /* Skip leading whitespace, then read in a quotation.
 125      If we hit EOF before we find a non-whitespace char, recurse. */
 126   while (isspace(c = getc(fp)))
 127     ;
 128   if (c == EOF) {
 129     yow(fp);
 130     return;
 131   }
 132
 133   bufsize = BUFSIZE;
 134   buf = malloc(bufsize);
 135   if (buf == (char *)0) {
 136     fprintf(stderr, "can't allocate any memory\n");
 137     exit (3);
 138   }
 139
 140   buf[i++] = c;
 141   while ((c = getc(fp)) != SEP && c != EOF) {
 142     buf[i++] = c;
 143
 144     if (i == bufsize-1) {
 145       /* Yow! Is this quotation too long yet? */
 146       bufsize *= 2;
 147       buf = realloc(buf, bufsize);
 148       if (buf == (char *)0) {
 149         fprintf(stderr, "can't allocate more memory\n");
 150         exit (3);
 151       }
 152     }
 153   }
 154   buf[i++] = 0;
 155   printf("%s\n", buf);
 156 }
 157