/js/src/jslibmath.h

  1/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  2 * vim: set ts=4 sw=4 et tw=79:
  3 *
  4 * ***** BEGIN LICENSE BLOCK *****
  5 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  6 *
  7 * The contents of this file are subject to the Mozilla Public License Version
  8 * 1.1 (the "License"); you may not use this file except in compliance with
  9 * the License. You may obtain a copy of the License at
 10 * http://www.mozilla.org/MPL/
 11 *
 12 * Software distributed under the License is distributed on an "AS IS" basis,
 13 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 14 * for the specific language governing rights and limitations under the
 15 * License.
 16 *
 17 * The Original Code is Mozilla Communicator client code, released
 18 * March 31, 1998.
 19 *
 20 * The Initial Developer of the Original Code is
 21 * Netscape Communications Corporation.
 22 * Portions created by the Initial Developer are Copyright (C) 1998
 23 * the Initial Developer. All Rights Reserved.
 24 *
 25 * Contributor(s):
 26 *   IBM Corp.
 27 *
 28 * Alternatively, the contents of this file may be used under the terms of
 29 * either of the GNU General Public License Version 2 or later (the "GPL"),
 30 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 31 * in which case the provisions of the GPL or the LGPL are applicable instead
 32 * of those above. If you wish to allow use of your version of this file only
 33 * under the terms of either the GPL or the LGPL, and not to allow others to
 34 * use your version of this file under the terms of the MPL, indicate your
 35 * decision by deleting the provisions above and replace them with the notice
 36 * and other provisions required by the GPL or the LGPL. If you do not delete
 37 * the provisions above, a recipient may use your version of this file under
 38 * the terms of any one of the MPL, the GPL or the LGPL.
 39 *
 40 * ***** END LICENSE BLOCK ***** */
 41
 42#ifndef _LIBMATH_H
 43#define _LIBMATH_H
 44
 45#include <math.h>
 46#include "jsnum.h"
 47
 48/*
 49 * Use system provided math routines.
 50 */
 51
 52/* The right copysign function is not always named the same thing. */
 53#if __GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
 54#define js_copysign __builtin_copysign
 55#elif defined _WIN32
 56#if _MSC_VER < 1400
 57/* Try to work around apparent _copysign bustage in VC7.x. */
 58#define js_copysign js_copysign
 59extern double js_copysign(double, double);
 60#else
 61#define js_copysign _copysign
 62#endif
 63#else
 64#define js_copysign copysign
 65#endif
 66
 67#if defined(_M_X64) && defined(_MSC_VER) && _MSC_VER <= 1500
 68// This is a workaround for fmod bug (http://support.microsoft.com/kb/982107)
 69extern "C" double js_myfmod(double x, double y);
 70#define fmod js_myfmod
 71#endif
 72
 73/* Consistency wrapper for platform deviations in fmod() */
 74static inline double
 75js_fmod(double d, double d2)
 76{
 77#ifdef XP_WIN
 78    /*
 79     * Workaround MS fmod bug where 42 % (1/0) => NaN, not 42.
 80     * Workaround MS fmod bug where -0 % -N => 0, not -0.
 81     */
 82    if ((JSDOUBLE_IS_FINITE(d) && JSDOUBLE_IS_INFINITE(d2)) ||
 83        (d == 0 && JSDOUBLE_IS_FINITE(d2))) {
 84        return d;
 85    }
 86#endif
 87    return fmod(d, d2);
 88}
 89
 90namespace js {
 91
 92inline double
 93NumberDiv(double a, double b) {
 94    if (b == 0) {
 95        if (a == 0 || JSDOUBLE_IS_NaN(a) 
 96#ifdef XP_WIN
 97            || JSDOUBLE_IS_NaN(b) /* XXX MSVC miscompiles such that (NaN == 0) */
 98#endif
 99        )
100            return js_NaN;    
101
102        if (JSDOUBLE_IS_NEG(a) != JSDOUBLE_IS_NEG(b))
103            return js_NegativeInfinity;
104        return js_PositiveInfinity; 
105    }
106
107    return a / b;
108}
109
110}
111
112#endif /* _LIBMATH_H */
113