C++ mozilla::IsNaN方法代码示例

static bool
ValidateConstant(JSContext *cx, AsmJSModule::Global &global, HandleValue globalVal)
{
    RootedPropertyName field(cx, global.constantName());
    RootedValue v(cx, globalVal);

    if (global.constantKind() == AsmJSModule::Global::MathConstant) {
        if (!GetDataProperty(cx, v, cx->names().Math, &v))
            return false;
    }

    if (!GetDataProperty(cx, v, field, &v))
        return false;
    if (!v.isNumber())
        return LinkFail(cx, "math / global constant value needs to be a number");

    // NaN != NaN
    if (IsNaN(global.constantValue())) {
        if (!IsNaN(v.toNumber()))
            return LinkFail(cx, "global constant value needs to be NaN");
    } else {
        if (v.toNumber() != global.constantValue())
            return LinkFail(cx, "global constant value mismatch");
    }

    return true;
}

static bool
GetGlobalExport(JSContext* cx, const GlobalDescVector& globals, uint32_t globalIndex,
                const ValVector& globalImports, MutableHandleValue jsval)
{
    const GlobalDesc& global = globals[globalIndex];

    // Imports are located upfront in the globals array.
    Val val;
    switch (global.kind()) {
      case GlobalKind::Import:   val = globalImports[globalIndex]; break;
      case GlobalKind::Variable: MOZ_CRASH("mutable variables can't be exported");
      case GlobalKind::Constant: val = global.constantValue(); break;
    }

    switch (global.type()) {
      case ValType::I32: {
        jsval.set(Int32Value(val.i32()));
        return true;
      }
      case ValType::I64: {
        MOZ_ASSERT(JitOptions.wasmTestMode, "no int64 in asm.js/wasm");
        RootedObject obj(cx, CreateI64Object(cx, val.i64()));
        if (!obj)
            return false;
        jsval.set(ObjectValue(*obj));
        return true;
      }
      case ValType::F32: {
        float f = val.f32();
        if (JitOptions.wasmTestMode && IsNaN(f)) {
            RootedObject obj(cx, CreateCustomNaNObject(cx, &f));
            if (!obj)
                return false;
            jsval.set(ObjectValue(*obj));
            return true;
        }
        jsval.set(DoubleValue(double(f)));
        return true;
      }
      case ValType::F64: {
        double d = val.f64();
        if (JitOptions.wasmTestMode && IsNaN(d)) {
            RootedObject obj(cx, CreateCustomNaNObject(cx, &d));
            if (!obj)
                return false;
            jsval.set(ObjectValue(*obj));
            return true;
        }
        jsval.set(DoubleValue(d));
        return true;
      }
      default: {
        break;
      }
    }
    MOZ_CRASH("unexpected type when creating global exports");
}

bool
HashableValue::setValue(JSContext* cx, HandleValue v)
{
    if (v.isString()) {
        // Atomize so that hash() and operator==() are fast and infallible.
        JSString* str = AtomizeString(cx, v.toString(), DoNotPinAtom);
        if (!str)
            return false;
        value = StringValue(str);
    } else if (v.isDouble()) {
        double d = v.toDouble();
        int32_t i;
        if (NumberEqualsInt32(d, &i)) {
            // Normalize int32_t-valued doubles to int32_t for faster hashing and testing.
            value = Int32Value(i);
        } else if (IsNaN(d)) {
            // NaNs with different bits must hash and test identically.
            value = DoubleNaNValue();
        } else {
            value = v;
        }
    } else {
        value = v;
    }

    MOZ_ASSERT(value.isUndefined() || value.isNull() || value.isBoolean() || value.isNumber() ||
               value.isString() || value.isSymbol() || value.isObject());
    return true;
}

////////////////////////////////////////////////////
// nsGeoPositionCoords
////////////////////////////////////////////////////
nsGeoPositionCoords::nsGeoPositionCoords(double aLat, double aLong, double aAlt,
                                         double aHError, double aVError,
                                         double aHeading, double aSpeed)
    : mLat(aLat),
      mLong(aLong),
      mAlt(aAlt),
      mHError((aHError >= 0) ? aHError : 0)
      // altitudeAccuracy without an altitude doesn't make any sense.
      ,
      mVError((aVError >= 0 && !IsNaN(aAlt)) ? aVError : NaN())
      // If the hosting device is stationary (i.e. the value of the speed
      // attribute is 0), then the value of the heading attribute must be NaN
      // (or null).
      ,
      mHeading((aHeading >= 0 && aHeading < 360 && aSpeed > 0) ? aHeading
                                                               : NaN()),
      mSpeed(aSpeed >= 0 ? aSpeed : NaN()) {
  // Sanity check the location provider's results in debug builds. If the
  // location provider is returning bogus results, we'd like to know, but
  // we prefer to return some position data to JavaScript over a
  // POSITION_UNAVAILABLE error.
  MOZ_ASSERT(aLat >= -90 && aLat <= 90);
  MOZ_ASSERT(aLong >= -180 && aLong <= 180);
  MOZ_ASSERT(!(aLat == 0 && aLong == 0));  // valid but probably a bug

  MOZ_ASSERT(EqualOrNaN(mAlt, aAlt));
  MOZ_ASSERT(mHError == aHError);
  MOZ_ASSERT(EqualOrNaN(mVError, aVError));
  MOZ_ASSERT(EqualOrNaN(mHeading, aHeading));
  MOZ_ASSERT(EqualOrNaN(mSpeed, aSpeed));
}

static bool
RenderFloat32(WasmRenderContext& c, float f)
{
    if (IsNaN(f))
        return RenderNaN(c.sb(), f);
    return RenderDouble(c, double(f));
}

static double
max_double(double x, double y)
{
    // Math.max(num, NaN) => NaN, Math.max(-0, +0) => +0
    if (x > y || IsNaN(x) || (x == y && IsNegative(y)))
        return x;
    return y;
}

double
js::math_max_impl(double x, double y)
{
    // Math.max(num, NaN) => NaN, Math.max(-0, +0) => +0
    if (x > y || IsNaN(x) || (x == y && IsNegative(y)))
        return x;
    return y;
}

static bool
RenderFloat32(WasmRenderContext& c, RawF32 num)
{
    float f = num.fp();
    if (IsNaN(f))
        return RenderNaN(c.sb(), num);
    return RenderDouble(c, RawF64(double(f)));
}

double
js::math_exp_impl(MathCache *cache, double x)
{
#ifdef _WIN32
    if (!IsNaN(x)) {
        if (x == js_PositiveInfinity)
            return js_PositiveInfinity;
        if (x == js_NegativeInfinity)
            return 0.0;
    }
#endif
    return cache->lookup(exp, x);
}

static bool
DecodeConstF64(FunctionDecoder& f, ExprType expected)
{
    double value;
    if (!f.d().readFixedF64(&value))
        return f.fail("unable to read f64.const immediate");
    if (IsNaN(value)) {
        const double jsNaN = JS::GenericNaN();
        if (memcmp(&value, &jsNaN, sizeof(value)) != 0)
            return f.fail("NYI: NaN literals with custom payloads");
    }

    return CheckType(f, ExprType::F64, expected);
}

static bool
RenderDouble(WasmRenderContext& c, double num)
{
    if (IsNegativeZero(num))
        return c.buffer.append("-0");
    if (IsNaN(num))
        return c.buffer.append("nan");
    if (IsInfinite(num)) {
        if (num > 0)
            return c.buffer.append("infinity");
        return c.buffer.append("-infinity");
    }
    return NumberValueToStringBuffer(c.cx, DoubleValue(num), c.buffer);
}

static bool
DecodeConstF32(FunctionDecoder& f, ExprType* type)
{
    float value;
    if (!f.d().readFixedF32(&value))
        return f.fail("unable to read f32.const immediate");

    if (IsNaN(value)) {
        const float jsNaN = (float)JS::GenericNaN();
        if (memcmp(&value, &jsNaN, sizeof(value)) != 0)
            return f.fail("NYI: NaN literals with custom payloads");
    }

    *type = ExprType::F32;
    return true;
}

bool
js_math_max(JSContext *cx, unsigned argc, Value *vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    double maxval = NegativeInfinity();
    for (unsigned i = 0; i < args.length(); i++) {
        double x;
        if (!ToNumber(cx, args[i], &x))
            return false;
        // Math.max(num, NaN) => NaN, Math.max(-0, +0) => +0
        if (x > maxval || IsNaN(x) || (x == maxval && IsNegative(maxval)))
            maxval = x;
    }
    args.rval().setNumber(maxval);
    return true;
}

bool
js_math_min(JSContext *cx, unsigned argc, Value *vp)
{
    CallArgs args = CallArgsFromVp(argc, vp);

    double minval = PositiveInfinity<double>();
    for (unsigned i = 0; i < args.length(); i++) {
        double x;
        if (!ToNumber(cx, args[i], &x))
            return false;
        // Math.min(num, NaN) => NaN, Math.min(-0, +0) => -0
        if (x < minval || IsNaN(x) || (x == minval && IsNegativeZero(x)))
            minval = x;
    }
    args.rval().setNumber(minval);
    return true;
}

static JSObject*
CreateCustomNaNObject(JSContext* cx, T* addr)
{
    MOZ_ASSERT(IsNaN(*addr));

    RootedObject obj(cx, JS_NewPlainObject(cx));
    if (!obj)
        return nullptr;

    int32_t* i32 = (int32_t*)addr;
    RootedValue intVal(cx, Int32Value(i32[0]));
    if (!JS_DefineProperty(cx, obj, "nan_low", intVal, JSPROP_ENUMERATE))
        return nullptr;

    if (IsSame<double, T>::value) {
        intVal = Int32Value(i32[1]);
        if (!JS_DefineProperty(cx, obj, "nan_high", intVal, JSPROP_ENUMERATE))
            return nullptr;
    }

    return obj;
}