diplodocus.org Git - nmh/blob - sbr/vfgets.c

   1 /* vfgets.c -- virtual fgets
   2  *
   3  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/utils.h>
  10
  11 #define QUOTE   '\\'
  12
  13
  14 int
  15 vfgets (FILE *in, char **bp)
  16 {
  17     int toggle;
  18     char *cp, *dp, *ep, *fp;
  19     static int len = 0;
  20     static char *pp = NULL;
  21
  22     if (pp == NULL)
  23         pp = mh_xmalloc ((size_t) (len = BUFSIZ));
  24
  25     for (ep = (cp = pp) + len - 1;;) {
  26         if (fgets (cp, ep - cp + 1, in) == NULL) {
  27             if (cp != pp) {
  28                 *bp = pp;
  29                 return 0;
  30             }
  31             return (ferror (in) && !feof (in) ? -1 : 1);
  32         }
  33
  34         if ((dp = cp + strlen (cp) - 2) < cp || *dp != QUOTE) {
  35 wrong_guess:
  36             if (cp > ++dp)
  37                 adios (NULL, "vfgets() botch -- you lose big");
  38             if (*dp == '\n') {
  39                 *bp = pp;
  40                 return 0;
  41             }
  42             cp = ++dp;
  43         } else {
  44             for (fp = dp - 1, toggle = 0; fp >= cp; fp--) {
  45                 if (*fp != QUOTE)
  46                     break;
  47                 toggle = !toggle;
  48             }
  49             if (toggle)
  50                 goto wrong_guess;
  51
  52             if (*++dp == '\n') {
  53                 *--dp = 0;
  54                 cp = dp;
  55             } else {
  56                 cp = ++dp;
  57             }
  58         }
  59
  60         if (cp >= ep) {
  61             int curlen = cp - pp;
  62
  63             dp = mh_xrealloc (pp, (size_t) (len += BUFSIZ));
  64             cp = dp + curlen;
  65             ep = (pp = dp) + len - 1;
  66         }
  67     }
  68 }