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