libio/vswprintf.c

   1 /* Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include "libioP.h"
  29 #include "strfile.h"
  30
  31
  32 typedef struct
  33 {
  34   _IO_strfile f;
  35   /* This is used for the characters which do not fit in the buffer
  36      provided by the user.  */
  37   wchar_t overflow_buf[64];
  38 } _IO_strnfile;
  39
  40
  41 static wint_t _IO_wstrn_overflow __P ((_IO_FILE *fp, wint_t c));
  42
  43 static wint_t
  44 _IO_wstrn_overflow (fp, c)
  45      _IO_FILE *fp;
  46      wint_t c;
  47 {
  48   /* When we come to here this means the user supplied buffer is
  49      filled.  But since we must return the number of characters which
  50      would have been written in total we must provide a buffer for
  51      further use.  We can do this by writing on and on in the overflow
  52      buffer in the _IO_strnfile structure.  */
  53   _IO_strnfile *snf = (_IO_strnfile *) fp;
  54
  55   if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
  56     {
  57       /* Terminate the string.  We know that there is room for at
  58          least one more character since we initialized the stream with
  59          a size to make this possible.  */
  60       *fp->_wide_data->_IO_write_ptr = '\0';
  61
  62       _IO_wsetb (fp, snf->overflow_buf,
  63                  snf->overflow_buf + (sizeof (snf->overflow_buf)
  64                                       / sizeof (wchar_t)), 0);
  65
  66       fp->_wide_data->_IO_write_base = snf->overflow_buf;
  67       fp->_wide_data->_IO_read_base = snf->overflow_buf;
  68       fp->_wide_data->_IO_read_ptr = snf->overflow_buf;
  69       fp->_wide_data->_IO_read_end = (snf->overflow_buf
  70                                       + (sizeof (snf->overflow_buf)
  71                                          / sizeof (wchar_t)));
  72     }
  73
  74   fp->_wide_data->_IO_write_ptr = snf->overflow_buf;
  75   fp->_wide_data->_IO_write_end = snf->overflow_buf;
  76
  77   /* Since we are not really interested in storing the characters
  78      which do not fit in the buffer we simply ignore it.  */
  79   return c;
  80 }
  81
  82
  83 static struct _IO_jump_t _IO_wstrn_jumps =
  84 {
  85   JUMP_INIT_DUMMY,
  86   JUMP_INIT(finish, _IO_wstr_finish),
  87   JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow),
  88   JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow),
  89   JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
  90   JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail),
  91   JUMP_INIT(xsputn, _IO_wdefault_xsputn),
  92   JUMP_INIT(xsgetn, _IO_wdefault_xsgetn),
  93   JUMP_INIT(seekoff, _IO_wstr_seekoff),
  94   JUMP_INIT(seekpos, _IO_default_seekpos),
  95   JUMP_INIT(setbuf, (_IO_setbuf_t) _IO_wdefault_setbuf),
  96   JUMP_INIT(sync, _IO_default_sync),
  97   JUMP_INIT(doallocate, _IO_wdefault_doallocate),
  98   JUMP_INIT(read, _IO_default_read),
  99   JUMP_INIT(write, _IO_default_write),
 100   JUMP_INIT(seek, _IO_default_seek),
 101   JUMP_INIT(close, _IO_default_close),
 102   JUMP_INIT(stat, _IO_default_stat),
 103   JUMP_INIT(showmanyc, _IO_default_showmanyc),
 104   JUMP_INIT(imbue, _IO_default_imbue)
 105 };
 106
 107
 108 int
 109 _IO_vswprintf (string, maxlen, format, args)
 110      wchar_t *string;
 111      _IO_size_t maxlen;
 112      const wchar_t *format;
 113      _IO_va_list args;
 114 {
 115   _IO_strnfile sf;
 116   int ret;
 117   struct _IO_wide_data wd;
 118 #ifdef _IO_MTSAFE_IO
 119   _IO_lock_t lock;
 120   sf.f._sbf._f._lock = &lock;
 121 #endif
 122
 123   /* We need to handle the special case where MAXLEN is 0.  Use the
 124      overflow buffer right from the start.  */
 125   if (maxlen == 0)
 126     {
 127       string = sf.overflow_buf;
 128       maxlen = sizeof (sf.overflow_buf) / sizeof (wchar_t);
 129     }
 130
 131   _IO_no_init (&sf.f._sbf._f, 0, 0, &wd, &_IO_wstrn_jumps);
 132   _IO_fwide (&sf.f._sbf._f, 1);
 133   string[0] = L'\0';
 134   _IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
 135   ret = _IO_vfwprintf ((_IO_FILE *) &sf.f._sbf, format, args);
 136
 137   if (sf.f._sbf._f._wide_data->_IO_buf_base != sf.overflow_buf)
 138     *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
 139   return ret;
 140 }
 141
 142 #ifdef weak_alias
 143 weak_alias (_IO_vswprintf, __vswprintf)
 144 weak_alias (_IO_vswprintf, vswprintf)
 145 #endif