path: root/libc/misc/wchar/wchar.c

/*  Copyright (C) 2002     Manuel Novoa III
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*  ATTENTION!   ATTENTION!   ATTENTION!   ATTENTION!   ATTENTION!
 *
 *  Besides uClibc, I'm using this code in my libc for elks, which is
 *  a 16-bit environment with a fairly limited compiler.  It would make
 *  things much easier for me if this file isn't modified unnecessarily.
 *  In particular, please put any new or replacement functions somewhere
 *  else, and modify the makefile to use your version instead.
 *  Thanks.  Manuel
 *
 *  ATTENTION!   ATTENTION!   ATTENTION!   ATTENTION!   ATTENTION! */


/* May 23, 2002     Initial Notes:
 *
 * I'm still tweaking this stuff, but it passes the tests I've thrown
 * at it, and Erik needs it for the gcc port.  The glibc extension
 * __wcsnrtombs() hasn't been tested, as I didn't find a test for it
 * in the glibc source.  I also need to fix the behavior of
 * _wchar_utf8sntowcs() if the max number of wchars to convert is 0.
 *
 * UTF-8 -> wchar -> UTF-8 conversion tests on Markus Kuhn's UTF-8-demo.txt
 * file on my platform (x86) show about 5-10% faster conversion speed than
 * glibc with mbsrtowcs()/wcsrtombs() and almost twice as fast as glibc with
 * individual mbrtowc()/wcrtomb() calls.
 *
 * If 'DECODER' is defined, then _wchar_utf8sntowcs() will be compiled
 * as a fail-safe UTF-8 decoder appropriate for a terminal, etc.  which
 * needs to deal gracefully with whatever is sent to it.  In that mode,
 * it passes Markus Kuhn's UTF-8-test.txt stress test.  I plan to add
 * an arg to force that behavior, so the interface will be changing.
 *
 * I need to fix the error checking for 16-bit wide chars.  This isn't
 * an issue for uClibc, but may be for ELKS.  I'm currently not sure
 * if I'll use 16-bit, 32-bit, or configureable wchars in ELKS.
 *
 * July 1, 2002
 *
 * Fixed _wchar_utf8sntowcs() for the max number of wchars == 0 case.
 * Fixed nul-char bug in btowc(), and another in __mbsnrtowcs() for 8-bit
 *    locales.
 * Enabled building of a C/POSIX-locale-only version, so full locale support
 *    no longer needs to be enabled.
 *
 * Nov 4, 2002
 *
 * Fixed a bug in _wchar_wcsntoutf8s().  Don't store wcs position if dst is NULL.
 * Also, introduce an awful hack into _wchar_wcsntoutf8s() and wcsrtombs() in
 *   order to support %ls in printf.  See comments below for details.
 * Change behaviour of wc<->mb functions when in the C locale.  Now they do
 *   a 1-1 map for the range 0x80-UCHAR_MAX.  This is for backwards compatibility
 *   and consistency with the stds requirements that a printf format string by
 *   a valid multibyte string beginning and ending in it's initial shift state.
 *
 * Nov 5, 2002
 *
 * Forgot to change btowc and wctob when I changed the wc<->mb functions yesterday.
 *
 * Nov 7, 2002
 *
 * Add wcwidth and wcswidth, based on Markus Kuhn's wcwidth of 2002-05-08.
 *   Added some size/speed optimizations and integrated it into my locale
 *   framework.  Minimally tested at the moment, but the stub C-locale
 *   version (which most people would probably be using) should be fine.
 *
 * Nov 21, 2002
 *
 * Revert the wc<->mb changes from earlier this month involving the C-locale.
 * Add a couple of ugly hacks to support *wprintf.
 * Add a mini iconv() and iconv implementation (requires locale support).
 *
 * Manuel
 */

#define _GNU_SOU