The Tor Browser: js/src/jslibmath.h@a63d609f5ebe

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #ifndef jslibmath_h

     8 #define jslibmath_h

    10 #include "mozilla/FloatingPoint.h"

    12 #include <math.h>

    14 #include "jsnum.h"

    16 /*

    17  * Use system provided math routines.

    18  */

    20 /* The right copysign function is not always named the same thing. */

    21 #ifdef __GNUC__

    22 #define js_copysign __builtin_copysign

    23 #elif defined _WIN32

    24 #define js_copysign _copysign

    25 #else

    26 #define js_copysign copysign

    27 #endif

    29 /* Consistency wrapper for platform deviations in fmod() */

    30 static inline double

    31 js_fmod(double d, double d2)

    32 {

    33 #ifdef XP_WIN

    34     /*

    35      * Workaround MS fmod bug where 42 % (1/0) => NaN, not 42.

    36      * Workaround MS fmod bug where -0 % -N => 0, not -0.

    37      */

    38     if ((mozilla::IsFinite(d) && mozilla::IsInfinite(d2)) ||

    39         (d == 0 && mozilla::IsFinite(d2))) {

    40         return d;

    41     }

    42 #endif

    43     return fmod(d, d2);

    44 }

    46 namespace js {

    48 inline double

    49 NumberDiv(double a, double b)

    50 {

    51     if (b == 0) {

    52         if (a == 0 || mozilla::IsNaN(a)

    53 #ifdef XP_WIN

    54             || mozilla::IsNaN(b) /* XXX MSVC miscompiles such that (NaN == 0) */

    55 #endif

    56         )

    57             return JS::GenericNaN();

    59         if (mozilla::IsNegative(a) != mozilla::IsNegative(b))

    60             return mozilla::NegativeInfinity<double>();

    61         return mozilla::PositiveInfinity<double>();

    62     }

    64     return a / b;

    65 }

    67 inline double

    68 NumberMod(double a, double b) {

    69     if (b == 0)

    70         return JS::GenericNaN();

    71     return js_fmod(a, b);

    72 }

    74 }

    76 #endif /* jslibmath_h */

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