c_io_libio.h: Tweak.

2000-08-08  Benjamin Kosnik  <bkoz@cygnus.com>
	    Ulrich Drepper  <drepper@cygnus.com>

	* config/c_io_libio.h: Tweak.
	* config/c_io_libio_codecvt.c: New file.
	* libio/Makefile.am: Add c_codecvt.c.
	* libio/Makefile.in: Regenerate.
	* libio/genops.c (_IO_unbuffer_write): Don't call _IO_SETBUF if the
	stream is not orientated.

	* acinclude.m4: Add config/c_io_libio_codecvt.c dummy file, until
	encoding gets fleshed out.

	* bits/basic_file.h: Add specialization declarations.
	* config/c_io_libio.cc: Add specializations for pbackfail, uflow.

	* config/c_io_libio.h: Add __c_wfile_type.
	* bits/basic_file.h: Add _M_wfile.

	* config/c_io_libio.cc (__basic_file<char>): Initialize the
	streams without setting the orientation of the underlying FILE to
	either wide or narrow.
	(__basic_file<wchar_t>)): Enable tricky wchar_t io bits.

From-SVN: r35583

libstdc++-v3/config/c_io_libio_codecvt.c

@@ -0,0 +1,150 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc.
+   This file is part of the GNU IO Library.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this library; see the file COPYING.  If not, write to
+   the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA.
+
+   As a special exception, if you link this library with files
+   compiled with a GNU compiler to produce an executable, this does
+   not cause the resulting executable to be covered by the GNU General
+   Public License.  This exception does not however invalidate any
+   other reasons why the executable file might be covered by the GNU
+   General Public License.  */
+
+/* Slightly modified from glibc/libio/iofwide.c */
+
+#include <libio.h>
+
+
+/* Prototypes of libio's codecvt functions.  */
+static enum __codecvt_result 
+do_out(struct _IO_codecvt *codecvt, __mbstate_t *statep,
+       const wchar_t *from_start, const wchar_t *from_end,
+       const wchar_t **from_stop, char *to_start, char *to_end, 
+       char **to_stop);
+
+static enum __codecvt_result 
+do_unshift(struct _IO_codecvt *codecvt, __mbstate_t *statep, char *to_start, 
+	   char *to_end, char **to_stop);
+
+static enum __codecvt_result 
+do_in(struct _IO_codecvt *codecvt, __mbstate_t *statep, 
+      const char *from_start, const char *from_end, const char **from_stop, 
+      wchar_t *to_start, wchar_t *to_end, wchar_t **to_stop);
+
+static int 
+do_encoding(struct _IO_codecvt *codecvt);
+
+static int 
+do_length(struct _IO_codecvt *codecvt, __mbstate_t *statep, 
+	  const char *from_start, const char *from_end, _IO_size_t max);
+
+static int 
+do_max_length(struct _IO_codecvt *codecvt);
+
+static int 
+do_always_noconv(struct _IO_codecvt *codecvt);
+
+
+/* The functions used in `codecvt' for libio are always the same.  */
+struct _IO_codecvt __c_libio_codecvt =
+{
+  .__codecvt_destr = NULL,		/* Destructor, never used.  */
+  .__codecvt_do_out = do_out,
+  .__codecvt_do_unshift = do_unshift,
+  .__codecvt_do_in = do_in,
+  .__codecvt_do_encoding = do_encoding,
+  .__codecvt_do_always_noconv = do_always_noconv,
+  .__codecvt_do_length = do_length,
+  .__codecvt_do_max_length = do_max_length
+};
+
+static enum __codecvt_result
+do_out(struct _IO_codecvt *codecvt, __mbstate_t *statep,
+       const wchar_t *from_start, const wchar_t *from_end,
+       const wchar_t **from_stop, char *to_start, char *to_end,
+       char **to_stop)
+{
+  enum __codecvt_result res = __codecvt_ok;
+
+  while (from_start < from_end)
+    {
+      if (to_start >= to_end)
+	{
+	  res = __codecvt_partial;
+	  break;
+	}
+      *to_start++ = (char) *from_start++;
+    }
+
+  *from_stop = from_start;
+  *to_stop = to_start;
+
+  return res;
+}
+
+
+static enum __codecvt_result
+do_unshift(struct _IO_codecvt *codecvt, __mbstate_t *statep,
+	   char *to_start, char *to_end, char **to_stop)
+{
+  *to_stop = to_start;
+  return __codecvt_ok;
+}
+
+
+static enum __codecvt_result
+do_in(struct _IO_codecvt *codecvt, __mbstate_t *statep,
+      const char *from_start, const char *from_end, const char **from_stop,
+      wchar_t *to_start, wchar_t *to_end, wchar_t **to_stop)
+{
+  enum __codecvt_result res = __codecvt_ok;
+
+  while (from_start < from_end)
+    {
+      if (to_start >= to_end)
+	{
+	  res = __codecvt_partial;
+	  break;
+	}
+      *to_start++ = (wchar_t) *from_start++;
+    }
+
+  *from_stop = from_start;
+  *to_stop = to_start;
+
+  return res;
+}
+
+
+static int
+do_encoding(struct _IO_codecvt *codecvt)
+{ return 1; }
+
+
+static int
+do_always_noconv(struct _IO_codecvt *codecvt)
+{ return 0; }
+
+
+static int
+do_length(struct _IO_codecvt *codecvt, __mbstate_t *statep,
+	  const char *from_start, const char *from_end, _IO_size_t max)
+{ return from_end - from_start; }
+
+
+static int
+do_max_length(struct _IO_codecvt *codecvt)
+{ return 1; }