hash.cpp
/* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* enchant
* Copyright (C) 2003 Dom Lachowicz
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
* In addition, as a special exception, Dom Lachowicz
* gives permission to link the code of this program with
* non-LGPL Spelling Provider libraries (eg: a MSFT Office
* spell checker backend) and distribute linked combinations including
* the two. You must obey the GNU Lesser General Public License in all
* respects for all of the code used other than said providers. If you modify
* this file, you may extend this exception to your version of the
* file, but you are not obligated to do so. If you do not wish to
* do so, delete this exception statement from your version.
*/
/*
* hash.c - a simple hash function for ispell
*
* Pace Willisson, 1983
*
* Copyright 1992, 1993, Geoff Kuenning, Granada Hills, CA
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All modifications to the source code must be clearly marked as
* such. Binary redistributions based on modified source code
* must be clearly marked as modified versions in the documentation
* and/or other materials provided with the distribution.
* 4. All advertising materials mentioning features or use of this software
* must display the following acknowledgment:
* This product includes software developed by Geoff Kuenning and
* other unpaid contributors.
* 5. The name of Geoff Kuenning may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY GEOFF KUENNING AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL GEOFF KUENNING OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* $Log$
* Revision 1.1 2004/01/31 16:44:12 zrusin
* ISpell plugin.
*
* Revision 1.4 2003/08/14 17:51:27 dom
* update license - exception clause should be Lesser GPL
*
* Revision 1.3 2003/07/28 20:40:26 dom
* fix up the license clause, further win32-registry proof some directory getting functions
*
* Revision 1.2 2003/07/16 22:52:39 dom
* LGPL + exception license
*
* Revision 1.1 2003/07/15 01:15:05 dom
* ispell enchant backend
*
* Revision 1.2 2003/01/29 05:50:11 hippietrail
*
* Fixed my mess in EncodingManager.
* Changed many C casts to C++ casts.
*
* Revision 1.1 2003/01/24 05:52:33 hippietrail
*
* Refactored ispell code. Old ispell global variables had been put into
* an allocated structure, a pointer to which was passed to many functions.
* I have now made all such functions and variables private members of the
* ISpellChecker class. It was C OO, now it's C++ OO.
*
* I've fixed the makefiles and tested compilation but am unable to test
* operation. Please back out my changes if they cause problems which
* are not obvious or easy to fix.
*
* Revision 1.5 2002/09/19 05:31:15 hippietrail
*
* More Ispell cleanup. Conditional globals and DEREF macros are removed.
* K&R function declarations removed, converted to Doxygen style comments
* where possible. No code has been changed (I hope). Compiles for me but
* unable to test.
*
* Revision 1.4 2002/09/17 03:03:29 hippietrail
*
* After seeking permission on the developer list I've reformatted all the
* spelling source which seemed to have parts which used 2, 3, 4, and 8
* spaces for tabs. It should all look good with our standard 4-space
* tabs now.
* I've concentrated just on indentation in the actual code. More prettying
* could be done.
* * NO code changes were made *
*
* Revision 1.3 2002/09/13 17:20:13 mpritchett
* Fix more warnings for Linux build
*
* Revision 1.2 2001/05/12 16:05:42 thomasf
* Big pseudo changes to ispell to make it pass around a structure rather
* than rely on all sorts of gloabals willy nilly here and there. Also
* fixed our spelling class to work with accepting suggestions once more.
* This code is dirty, gross and ugly (not to mention still not supporting
* multiple hash sized just yet) but it works on my machine and will no
* doubt break other machines.
*
* Revision 1.1 2001/04/15 16:01:24 tomas_f
* moving to spell/xp
*
* Revision 1.3 1998/12/29 14:55:33 eric
*
* I've doctored the ispell code pretty extensively here. It is now
* warning-free on Win32. It also *works* on Win32 now, since I
* replaced all the I/O calls with ANSI standard ones.
*
* Revision 1.2 1998/12/28 23:11:30 eric
*
* modified spell code and integration to build on Windows.
* This is still a hack.
*
* Actually, it doesn't yet WORK on Windows. It just builds.
* SpellCheckInit is failing for some reason.
*
* Revision 1.1 1998/12/28 18:04:43 davet
* Spell checker code stripped from ispell. At this point, there are
* two external routines... the Init routine, and a check-a-word routine
* which returns a boolean value, and takes a 16 bit char string.
* The code resembles the ispell code as much as possible still.
*
* Revision 1.20 1994/01/25 07:11:34 geoff
* Get rid of all old RCS log lines in preparation for the 3.1 release.
*
*/
#include "ispell_checker.h"
/*
* The following hash algorithm is due to Ian Dall, with slight modifications
* by Geoff Kuenning to reflect the results of testing with the English
* dictionaries actually distributed with ispell.
*/
#define HASHSHIFT 5
#ifdef NO_CAPITALIZATION_SUPPORT
#define HASHUPPER(c) c
#else /* NO_CAPITALIZATION_SUPPORT */
#define HASHUPPER(c) mytoupper(c)
#endif /* NO_CAPITALIZATION_SUPPORT */
/*
* \param s
* \param hashtblsize
*/
int ISpellChecker::hash (ichar_t *s, int hashtblsize)
{
register long h = 0;
register int i;
#ifdef ICHAR_IS_CHAR
for (i = 4; i-- && *s != 0; )
h = (h << 8) | HASHUPPER (*s++);
#else /* ICHAR_IS_CHAR */
for (i = 2; i-- && *s != 0; )
h = (h << 16) | HASHUPPER (*s++);
#endif /* ICHAR_IS_CHAR */
while (*s != 0)
{
/*
* We have to do circular shifts the hard way, since C doesn't
* have them even though the hardware probably does. Oh, well.
*/
h = (h << HASHSHIFT)
| ((h >> (32 - HASHSHIFT)) & ((1 << HASHSHIFT) - 1));
h ^= HASHUPPER (*s++);
}
return static_cast<unsigned long>(h) % hashtblsize;
}

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