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

   1
   2 /*
   3  * vfgets.c -- virtual fgets
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9
  10 #define QUOTE   '\\'
  11
  12
  13 int
  14 vfgets (FILE *in, char **bp)
  15 {
  16     int toggle;
  17     char *cp, *dp, *ep, *fp;
  18     static int len = 0;
  19     static char *pp = NULL;
  20
  21     if (pp == NULL)
  22         if (!(pp = malloc ((size_t) (len = BUFSIZ))))
  23             adios (NULL, "unable to allocate string storage");
  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             } else {
  42                 cp = ++dp;
  43             }
  44         } else {
  45             for (fp = dp - 1, toggle = 0; fp >= cp; fp--) {
  46                 if (*fp != QUOTE)
  47                     break;
  48                 else
  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             if (!(dp = realloc (pp, (size_t) (len += BUFSIZ)))) {
  66                 adios (NULL, "unable to allocate string storage");
  67             } else {
  68                 cp = dp + curlen;
  69                 ep = (pp = dp) + len - 1;
  70             }
  71         }
  72     }
  73 }