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127 lines
4.2 KiB
C
127 lines
4.2 KiB
C
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Foundation code.
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*
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* The Initial Developer of the Original Code is Mozilla Foundation.
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* Portions created by the Initial Developer are Copyright (C) 2007
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Stuart Parmenter <stuart@mozilla.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsMathUtils_h__
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#define nsMathUtils_h__
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#include "nscore.h"
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#include <math.h>
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#include <float.h>
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/*
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* round
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*/
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inline NS_HIDDEN_(double) NS_round(double x)
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{
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return x >= 0.0 ? floor(x + 0.5) : ceil(x - 0.5);
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}
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inline NS_HIDDEN_(float) NS_roundf(float x)
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{
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return x >= 0.0f ? floorf(x + 0.5f) : ceilf(x - 0.5f);
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}
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inline NS_HIDDEN_(PRInt32) NS_lround(double x)
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{
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return x >= 0.0 ? PRInt32(x + 0.5) : PRInt32(x - 0.5);
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}
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/* NS_roundup30 rounds towards infinity for positive and */
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/* negative numbers. */
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#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__)
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inline NS_HIDDEN_(PRInt32) NS_lroundup30(float x)
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{
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/* Code derived from Laurent de Soras' paper at */
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/* http://ldesoras.free.fr/doc/articles/rounding_en.pdf */
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/* Rounding up on Windows is expensive using the float to */
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/* int conversion and the floor function. A faster */
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/* approach is to use f87 rounding while assuming the */
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/* default rounding mode of rounding to the nearest */
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/* integer. This rounding mode, however, actually rounds */
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/* to the nearest integer so we add the floating point */
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/* number to itself and add our rounding factor before */
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/* doing the conversion to an integer. We then do a right */
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/* shift of one bit on the integer to divide by two. */
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/* This routine doesn't handle numbers larger in magnitude */
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/* than 2^30 but this is fine for NSToCoordRound because */
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/* Coords are limited to 2^30 in magnitude. */
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static const double round_to_nearest = 0.5f;
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int i;
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__asm {
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fld x ; load fp argument
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fadd st, st(0) ; double it
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fadd round_to_nearest ; add the rounding factor
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fistp dword ptr i ; convert the result to int
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}
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return i >> 1; /* divide by 2 */
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}
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#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */
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inline NS_HIDDEN_(PRInt32) NS_lroundf(float x)
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{
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return x >= 0.0f ? PRInt32(x + 0.5f) : PRInt32(x - 0.5f);
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}
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/*
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* ceil
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*/
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inline NS_HIDDEN_(double) NS_ceil(double x)
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{
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return ceil(x);
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}
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inline NS_HIDDEN_(float) NS_ceilf(float x)
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{
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return ceilf(x);
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}
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/*
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* floor
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*/
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inline NS_HIDDEN_(double) NS_floor(double x)
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{
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return floor(x);
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}
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inline NS_HIDDEN_(float) NS_floorf(float x)
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{
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return floorf(x);
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}
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#endif
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