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 "vfgets.h"
  10 #include "error.h"
  11 #include "h/utils.h"
  12
  13 #define QUOTE   '\\'
  14
  15
  16 int
  17 vfgets (FILE *in, char **bp)
  18 {
  19     int toggle;
  20     char *cp, *dp, *ep, *fp;
  21     static int len = 0;
  22     static char *pp = NULL;
  23
  24     if (pp == NULL)
  25         pp = mh_xmalloc ((size_t) (len = BUFSIZ));
  26
  27     for (ep = (cp = pp) + len - 1;;) {
  28         if (fgets (cp, ep - cp + 1, in) == NULL) {
  29             if (cp != pp) {
  30                 *bp = pp;
  31                 return 0;
  32             }
  33             return ferror(in) && !feof(in) ? -1 : 1;
  34         }
  35
  36         if ((dp = cp + strlen (cp) - 2) < cp || *dp != QUOTE) {
  37 wrong_guess:
  38             if (cp > ++dp)
  39                 die("vfgets() botch -- you lose big");
  40             if (*dp == '\n') {
  41                 *bp = pp;
  42                 return 0;
  43             }
  44             cp = ++dp;
  45         } else {
  46             for (fp = dp - 1, toggle = 0; fp >= cp; fp--) {
  47                 if (*fp != QUOTE)
  48                     break;
  49                 toggle = !toggle;
  50             }
  51             if (toggle)
  52                 goto wrong_guess;
  53
  54             if (*++dp == '\n') {
  55                 *--dp = 0;
  56                 cp = dp;
  57             } else {
  58                 cp = ++dp;
  59             }
  60         }
  61
  62         if (cp >= ep) {
  63             int curlen = cp - pp;
  64
  65             dp = mh_xrealloc (pp, (size_t) (len += BUFSIZ));
  66             cp = dp + curlen;
  67             ep = (pp = dp) + len - 1;
  68         }
  69     }
  70 }