Package com.google.javascript.jscomp.base

Class JSCompDoubles

java.lang.Object
com.google.javascript.jscomp.base.JSCompDoubles
public final class JSCompDoubles extends Object
Basic double functions used by JSComp.

  • Method Details

    • isExactInt32

      public static boolean isExactInt32(double x)
      Can a 32 bit int exactly represent `x`?

      Many double values are not exact integers. Many that are integers are too large to fit into a Java int.

      This function does not guarantee that a value can be round-tripped from double to int to double and have an identical bit pattern. Notably, 0.0 and -0.0 both represent exactly 0.

    • isExactInt64

      public static boolean isExactInt64(double x)
      Can a 64 bit int exactly represent `x`?

      Many double values are not exact integers. Many that are integers are too large to fit into a Java long.

      This function does not guarantee that a value can be round-tripped from double to long to double and have an identical bit pattern. Notably, 0.0 and -0.0 both represent exactly 0.

    • isMathematicalInteger

      public static boolean isMathematicalInteger(double x)
      Does `x` exactly represent an value with no fractional part?

      The value may be too large to fit in a primitive integral type, such as long.

      Returns false for NaN and Infinity.

      This should behave identically to Guava DoubleMath.isMathematicalInteger but is J2CL compatible.

    • isAtLeastIntegerPrecision

      public static boolean isAtLeastIntegerPrecision(double x)
      Does `x` have precision down to the "ones column"?

      A double can hold exact integer values that are very large, but to do so it may loose precision at the scale of "ones". That is "largeDouble + 1.0 == largeDouble" may be true.

      Returns false for NaN and Infinity.

    • isNegative

      public static boolean isNegative(double x)
      Does `x` carry a negative sign?

      Because -0.0 == 0.0, it is not enough to check `x invalid input: '<' 0.0` to determine if a double is negative. This function identifies the -0.0 case.

    • isPositive

      public static boolean isPositive(double x)
      Does `x` not carry a negative sign?

      Because -0.0 == 0.0, it is not enough to check `x invalid input: '<' 0.0` to determine if a double is negative. This function identifies the -0.0 case.

    • isEitherZero

      public static boolean isEitherZero(double x)
      Is `x` positive or negative zero?

    • ecmascriptToInt32

      public static int ecmascriptToInt32(double number)
      The ECMAScript ToInt32 abstract operation.

      See https://262.ecma-international.org/5.1/#sec-9.5

    • ecmascriptToUint32

      public static int ecmascriptToUint32(double number)
      The ECMAScript ToUint32 abstract operation.

      Java has no uint types, so the caller must remember to treat the returned bits as a uint.

      See https://262.ecma-international.org/5.1/#sec-9.6