src/stdio/ungetwc.c

   1 #include "stdio_impl.h"
   2 #include "locale_impl.h"
   3 #include <wchar.h>
   4 #include <limits.h>
   5 #include <ctype.h>
   6 #include <string.h>
   7
   8 wint_t ungetwc(wint_t c, FILE *f)
   9 {
  10         unsigned char mbc[MB_LEN_MAX];
  11         int l;
  12         locale_t *ploc = &CURRENT_LOCALE, loc = *ploc;
  13
  14         FLOCK(f);
  15
  16         if (f->mode <= 0) fwide(f, 1);
  17         *ploc = f->locale;
  18
  19         if (!f->rpos) __toread(f);
  20         if (!f->rpos || c == WEOF || (l = wcrtomb((void *)mbc, c, 0)) < 0 ||
  21             f->rpos < f->buf - UNGET + l) {
  22                 FUNLOCK(f);
  23                 *ploc = loc;
  24                 return WEOF;
  25         }
  26
  27         if (isascii(c)) *--f->rpos = c;
  28         else memcpy(f->rpos -= l, mbc, l);
  29
  30         f->flags &= ~F_EOF;
  31
  32         FUNLOCK(f);
  33         *ploc = loc;
  34         return c;
  35 }