libio/vswprintf.c

   1 /* Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU IO Library.
   3
   4    This library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License as
   6    published by the Free Software Foundation; either version 2, or (at
   7    your option) any later version.
   8
   9    This library is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this library; see the file COPYING.  If not, write to
  16    the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  17    MA 02111-1307, USA.
  18
  19    As a special exception, if you link this library with files
  20    compiled with a GNU compiler to produce an executable, this does
  21    not cause the resulting executable to be covered by the GNU General
  22    Public License.  This exception does not however invalidate any
  23    other reasons why the executable file might be covered by the GNU
  24    General Public License.  */
  25
  26 #include "libioP.h"
  27 #include "strfile.h"
  28
  29
  30 typedef struct
  31 {
  32   _IO_strfile f;
  33   /* This is used for the characters which do not fit in the buffer
  34      provided by the user.  */
  35   wchar_t overflow_buf[64];
  36 } _IO_strnfile;
  37
  38
  39 static wint_t _IO_wstrn_overflow __P ((_IO_FILE *fp, wint_t c));
  40
  41 static wint_t
  42 _IO_wstrn_overflow (fp, c)
  43      _IO_FILE *fp;
  44      wint_t c;
  45 {
  46   /* When we come to here this means the user supplied buffer is
  47      filled.  But since we must return the number of characters which
  48      would have been written in total we must provide a buffer for
  49      further use.  We can do this by writing on and on in the overflow
  50      buffer in the _IO_strnfile structure.  */
  51   _IO_strnfile *snf = (_IO_strnfile *) fp;
  52
  53   if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
  54     {
  55       /* Terminate the string.  We know that there is room for at
  56          least one more character since we initialized the stream with
  57          a size to make this possible.  */
  58       *fp->_wide_data->_IO_write_ptr = '\0';
  59
  60       _IO_wsetb (fp, snf->overflow_buf,
  61                  snf->overflow_buf + (sizeof (snf->overflow_buf)
  62                                       / sizeof (wchar_t)), 0);
  63
  64       fp->_wide_data->_IO_write_base = snf->overflow_buf;
  65       fp->_wide_data->_IO_read_base = snf->overflow_buf;
  66       fp->_wide_data->_IO_read_ptr = snf->overflow_buf;
  67       fp->_wide_data->_IO_read_end = (snf->overflow_buf
  68                                       + (sizeof (snf->overflow_buf)
  69                                          / sizeof (wchar_t)));
  70     }
  71
  72   fp->_wide_data->_IO_write_ptr = snf->overflow_buf;
  73   fp->_wide_data->_IO_write_end = snf->overflow_buf;
  74
  75   /* Since we are not really interested in storing the characters
  76      which do not fit in the buffer we simply ignore it.  */
  77   return c;
  78 }
  79
  80
  81 static struct _IO_jump_t _IO_wstrn_jumps =
  82 {
  83   JUMP_INIT_DUMMY,
  84   JUMP_INIT(finish, _IO_wstr_finish),
  85   JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow),
  86   JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow),
  87   JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
  88   JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail),
  89   JUMP_INIT(xsputn, _IO_wdefault_xsputn),
  90   JUMP_INIT(xsgetn, _IO_wdefault_xsgetn),
  91   JUMP_INIT(seekoff, _IO_wstr_seekoff),
  92   JUMP_INIT(seekpos, _IO_default_seekpos),
  93   JUMP_INIT(setbuf, (_IO_setbuf_t) _IO_wdefault_setbuf),
  94   JUMP_INIT(sync, _IO_default_sync),
  95   JUMP_INIT(doallocate, _IO_wdefault_doallocate),
  96   JUMP_INIT(read, _IO_default_read),
  97   JUMP_INIT(write, _IO_default_write),
  98   JUMP_INIT(seek, _IO_default_seek),
  99   JUMP_INIT(close, _IO_default_close),
 100   JUMP_INIT(stat, _IO_default_stat),
 101   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 102   JUMP_INIT(imbue, _IO_default_imbue)
 103 };
 104
 105
 106 int
 107 _IO_vswprintf (string, maxlen, format, args)
 108      wchar_t *string;
 109      _IO_size_t maxlen;
 110      const wchar_t *format;
 111      _IO_va_list args;
 112 {
 113   _IO_strnfile sf;
 114   int ret;
 115   struct _IO_wide_data wd;
 116 #ifdef _IO_MTSAFE_IO
 117   _IO_lock_t lock;
 118   sf.f._sbf._f._lock = &lock;
 119 #endif
 120
 121   /* We need to handle the special case where MAXLEN is 0.  Use the
 122      overflow buffer right from the start.  */
 123   if (maxlen == 0)
 124     {
 125       string = sf.overflow_buf;
 126       maxlen = sizeof (sf.overflow_buf) / sizeof (wchar_t);
 127     }
 128
 129   _IO_no_init (&sf.f._sbf._f, 0, 0, &wd, &_IO_wstrn_jumps);
 130   _IO_fwide (&sf.f._sbf._f, 1);
 131   string[0] = L'\0';
 132   _IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
 133   ret = _IO_vfwprintf ((_IO_FILE *) &sf.f._sbf, format, args);
 134
 135   if (sf.f._sbf._f._wide_data->_IO_buf_base != sf.overflow_buf)
 136     *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
 137   return ret;
 138 }
 139
 140 #ifdef weak_alias
 141 weak_alias (_IO_vswprintf, __vswprintf)
 142 weak_alias (_IO_vswprintf, vswprintf)
 143 #endif