Пример #1
0
JSBool /* ES5 15.8.2.15. */
js_math_round(JSContext *cx, unsigned argc, Value *vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    if (args.length() == 0) {
        args.rval().setDouble(js_NaN);
        return true;
    }

    double x;
    if (!ToNumber(cx, args[0], &x))
        return false;

    int32_t i;
    if (DoubleIsInt32(x, &i)) {
        args.rval().setInt32(i);
        return true;
    }

    /* Some numbers are so big that adding 0.5 would give the wrong number. */
    if (ExponentComponent(x) >= 52) {
        args.rval().setNumber(x);
        return true;
    }

    args.rval().setNumber(js_copysign(floor(x + 0.5), x));
    return true;
}
Пример #2
0
float
js::math_roundf_impl(float x)
{
    int32_t ignored;
    if (NumberIsInt32(x, &ignored))
        return x;

    /* Some numbers are so big that adding 0.5 would give the wrong number. */
    if (ExponentComponent(x) >= int_fast16_t(FloatingPoint<float>::ExponentShift))
        return x;

    return js_copysign(floorf(x + 0.5f), x);
}
Пример #3
0
double
js::math_round_impl(double x)
{
    int32_t i;
    if (DoubleIsInt32(x, &i))
        return double(i);

    /* Some numbers are so big that adding 0.5 would give the wrong number. */
    if (ExponentComponent(x) >= 52)
        return x;

    return js_copysign(floor(x + 0.5), x);
}
Пример #4
0
double
js::math_round_impl(double x)
{
    int32_t ignored;
    if (NumberIsInt32(x, &ignored))
        return x;

    /* Some numbers are so big that adding 0.5 would give the wrong number. */
    if (ExponentComponent(x) >= int_fast16_t(FloatingPoint<double>::kExponentShift))
        return x;

    double add = (x >= 0) ? GetBiggestNumberLessThan(0.5) : 0.5;
    return js_copysign(floor(x + add), x);
}
Пример #5
0
static void
TestExponentComponent()
{
  MOZ_ASSERT(ExponentComponent(0.0) == -int_fast16_t(DoubleExponentBias));
  MOZ_ASSERT(ExponentComponent(-0.0) == -int_fast16_t(DoubleExponentBias));
  MOZ_ASSERT(ExponentComponent(0.125) == -3);
  MOZ_ASSERT(ExponentComponent(0.5) == -1);
  MOZ_ASSERT(ExponentComponent(1.0) == 0);
  MOZ_ASSERT(ExponentComponent(1.5) == 0);
  MOZ_ASSERT(ExponentComponent(2.0) == 1);
  MOZ_ASSERT(ExponentComponent(7) == 2);
  MOZ_ASSERT(ExponentComponent(PositiveInfinity()) == DoubleExponentBias + 1);
  MOZ_ASSERT(ExponentComponent(NegativeInfinity()) == DoubleExponentBias + 1);
  MOZ_ASSERT(ExponentComponent(UnspecifiedNaN()) == DoubleExponentBias + 1);
}