newlib/libc/stdio/fgetws.c

   1 /*-
   2  * Copyright (c) 2002-2004 Tim J. Robbins.
   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
  27 /*
  28 FUNCTION
  29 <<fgetws>>, <<fgetws_unlocked>>---get wide character string from a file or stream
  30
  31 INDEX
  32         fgetws
  33 INDEX
  34         fgetws_unlocked
  35 INDEX
  36         _fgetws_r
  37 INDEX
  38         _fgetws_unlocked_r
  39
  40 SYNOPSIS
  41         #include <wchar.h>
  42         wchar_t *fgetws(wchar_t *__restrict <[ws]>, int <[n]>,
  43                         FILE *__restrict <[fp]>);
  44
  45         #define _GNU_SOURCE
  46         #include <wchar.h>
  47         wchar_t *fgetws_unlocked(wchar_t *__restrict <[ws]>, int <[n]>,
  48                         FILE *__restrict <[fp]>);
  49
  50         #include <wchar.h>
  51         wchar_t *_fgetws_r(struct _reent *<[ptr]>, wchar_t *<[ws]>,
  52                            int <[n]>, FILE *<[fp]>);
  53
  54         #include <wchar.h>
  55         wchar_t *_fgetws_unlocked_r(struct _reent *<[ptr]>, wchar_t *<[ws]>,
  56                            int <[n]>, FILE *<[fp]>);
  57
  58 DESCRIPTION
  59 Reads at most <[n-1]> wide characters from <[fp]> until a newline
  60 is found. The wide characters including to the newline are stored
  61 in <[ws]>. The buffer is terminated with a 0.
  62
  63 <<fgetws_unlocked>> is a non-thread-safe version of <<fgetws>>.
  64 <<fgetws_unlocked>> may only safely be used within a scope
  65 protected by flockfile() (or ftrylockfile()) and funlockfile().  This
  66 function may safely be used in a multi-threaded program if and only
  67 if they are called while the invoking thread owns the (FILE *)
  68 object, as is the case after a successful call to the flockfile() or
  69 ftrylockfile() functions.  If threads are disabled, then
  70 <<fgetws_unlocked>> is equivalent to <<fgetws>>.
  71
  72 The <<_fgetws_r>> and <<_fgetws_unlocked_r>> functions are simply reentrant
  73 version of the above and are passed an additional reentrancy structure
  74 pointer: <[ptr]>.
  75
  76 RETURNS
  77 <<fgetws>> returns the buffer passed to it, with the data
  78 filled in. If end of file occurs with some data already
  79 accumulated, the data is returned with no other indication. If
  80 no data are read, NULL is returned instead.
  81
  82 PORTABILITY
  83 <<fgetws>> is required by C99 and POSIX.1-2001.
  84
  85 <<fgetws_unlocked>> is a GNU extension.
  86 */
  87
  88 #include <_ansi.h>
  89 #include <reent.h>
  90 #include <errno.h>
  91 #include <stdio.h>
  92 #include <string.h>
  93 #include <wchar.h>
  94 #include "local.h"
  95
  96 #ifdef __IMPL_UNLOCKED__
  97 #define _fgetws_r _fgetws_unlocked_r
  98 #define fgetws fgetws_unlocked
  99 #endif
 100
 101 wchar_t *
 102 _fgetws_r (struct _reent *ptr,
 103         wchar_t * ws,
 104         int n,
 105         FILE * fp)
 106 {
 107   wchar_t *wsp;
 108   size_t nconv;
 109   const char *src;
 110   unsigned char *nl;
 111
 112   _newlib_flockfile_start (fp);
 113   if (ORIENT (fp, 1) != 1)
 114     goto error;
 115
 116   if (n <= 0)
 117     {
 118       errno = EINVAL;
 119       goto error;
 120     }
 121
 122   if (fp->_r <= 0 && __srefill_r (ptr, fp))
 123     /* EOF */
 124     goto error;
 125   wsp = ws;
 126   do
 127     {
 128       src = (char *) fp->_p;
 129       nl = memchr (fp->_p, '\n', fp->_r);
 130       nconv = _mbsnrtowcs_r (ptr, wsp, &src,
 131                              /* Read all bytes up to the next NL, or up to the
 132                                 end of the buffer if there is no NL. */
 133                              nl != NULL ? (nl - fp->_p + 1) : fp->_r,
 134                              /* But never more than n - 1 wide chars. */
 135                              n - 1,
 136                              &fp->_mbstate);
 137       if (nconv == (size_t) -1)
 138         /* Conversion error */
 139         goto error;
 140       if (src == NULL)
 141         {
 142           /*
 143            * We hit a null byte. Increment the character count,
 144            * since mbsnrtowcs()'s return value doesn't include
 145            * the terminating null, then resume conversion
 146            * after the null.
 147            */
 148           nconv++;
 149           src = memchr (fp->_p, '\0', fp->_r);
 150           src++;
 151         }
 152       fp->_r -= (unsigned char *) src - fp->_p;
 153       fp->_p = (unsigned char *) src;
 154       n -= nconv;
 155       wsp += nconv;
 156     }
 157   while (wsp[-1] != L'\n' && n > 1 && (fp->_r > 0
 158          || __srefill_r (ptr, fp) == 0));
 159   if (wsp == ws)
 160     /* EOF */
 161     goto error;
 162   if (!mbsinit (&fp->_mbstate))
 163     /* Incomplete character */
 164     goto error;
 165   *wsp++ = L'\0';
 166   _newlib_flockfile_exit (fp);
 167   return ws;
 168
 169 error:
 170   _newlib_flockfile_end (fp);
 171   return NULL;
 172 }
 173
 174 wchar_t *
 175 fgetws (wchar_t *__restrict ws,
 176         int n,
 177         FILE *__restrict fp)
 178 {
 179   struct _reent *reent = _REENT;
 180
 181   CHECK_INIT (reent, fp);
 182   return _fgetws_r (reent, ws, n, fp);
 183 }