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

   1
   2 /*
   3  * vfgets.c -- virtual fgets
   4  *
   5  * $Id$
   6  *
   7  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   8  * COPYRIGHT file in the root directory of the nmh distribution for
   9  * complete copyright information.
  10  */
  11
  12 #include <h/mh.h>
  13
  14 #define QUOTE   '\\'
  15
  16
  17 int
  18 vfgets (FILE *in, char **bp)
  19 {
  20     int toggle;
  21     char *cp, *dp, *ep, *fp;
  22     static int len = 0;
  23     static char *pp = NULL;
  24
  25     if (pp == NULL)
  26         if (!(pp = malloc ((size_t) (len = BUFSIZ))))
  27             adios (NULL, "unable to allocate string storage");
  28
  29     for (ep = (cp = pp) + len - 1;;) {
  30         if (fgets (cp, ep - cp + 1, in) == NULL) {
  31             if (cp != pp) {
  32                 *bp = pp;
  33                 return 0;
  34             }
  35             return (ferror (in) && !feof (in) ? -1 : 1);
  36         }
  37
  38         if ((dp = cp + strlen (cp) - 2) < cp || *dp != QUOTE) {
  39 wrong_guess:
  40             if (cp > ++dp)
  41                 adios (NULL, "vfgets() botch -- you lose big");
  42             if (*dp == '\n') {
  43                 *bp = pp;
  44                 return 0;
  45             } else {
  46                 cp = ++dp;
  47             }
  48         } else {
  49             for (fp = dp - 1, toggle = 0; fp >= cp; fp--) {
  50                 if (*fp != QUOTE)
  51                     break;
  52                 else
  53                     toggle = !toggle;
  54             }
  55             if (toggle)
  56                 goto wrong_guess;
  57
  58             if (*++dp == '\n') {
  59                 *--dp = 0;
  60                 cp = dp;
  61             } else {
  62                 cp = ++dp;
  63             }
  64         }
  65
  66         if (cp >= ep) {
  67             int curlen = cp - pp;
  68
  69             if (!(dp = realloc (pp, (size_t) (len += BUFSIZ)))) {
  70                 adios (NULL, "unable to allocate string storage");
  71             } else {
  72                 cp = dp + curlen;
  73                 ep = (pp = dp) + len - 1;
  74             }
  75         }
  76     }
  77 }