StdLib/LibC/Stdio/ungetwc.c

   1 /*-
   2  * Copyright (c)2001 Citrus Project,
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $Citrus$
  27
  28   NetBSD: ungetwc.c,v 1.3 2005/06/12 05:21:27 lukem Exp
  29  */
  30 #include  <LibConfig.h>
  31 #include  <sys/EfiCdefs.h>
  32
  33 #include  <assert.h>
  34 #include  <errno.h>
  35 #include  <stdio.h>
  36 #include  <wchar.h>
  37 #include  "reentrant.h"
  38 #include  "local.h"
  39
  40 wint_t
  41 ungetwc(wint_t wc, FILE *fp)
  42 {
  43   struct wchar_io_data *wcio;
  44
  45   _DIAGASSERT(fp);
  46
  47   if (wc == WEOF)
  48     return WEOF;
  49
  50   FLOCKFILE(fp);
  51   _SET_ORIENTATION(fp, 1);
  52   /*
  53    * XXX since we have no way to transform a wchar string to
  54    * a char string in reverse order, we can't use ungetc.
  55    */
  56   /* XXX should we flush ungetc buffer? */
  57
  58   wcio = WCIO_GET(fp);
  59   if (wcio == 0) {
  60     FUNLOCKFILE(fp);
  61     errno = ENOMEM; /* XXX */
  62     return WEOF;
  63   }
  64
  65   if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
  66     FUNLOCKFILE(fp);
  67     return WEOF;
  68   }
  69
  70   wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = (wchar_t)wc;
  71   __sclearerr(fp);
  72   FUNLOCKFILE(fp);
  73
  74   return wc;
  75 }