Package org.apache.commons.rng.core.util

Class NumberFactory

  • public final class NumberFactory
extends java.lang.Object
    Utility for creating number types from one or two int values or one long value, or a sequence of bytes.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static double DOUBLE_MULTIPLIER
      The multiplier to convert the least significant 53-bits of a long to a double.
      private static float FLOAT_MULTIPLIER
      The multiplier to convert the least significant 24-bits of an int to a float.
      private static int INT_LOWEST_BYTE_MASK
      Lowest byte mask.
      private static int INT_SIZE
      Number of bytes in a int.
      private static long LONG_LOWEST_BYTE_MASK
      Lowest byte mask.
      private static int LONG_SIZE
      Number of bytes in a long.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private NumberFactory()
      Class contains only static methods.

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      private static void checkSize​(int expected, int actual)  
      static int extractHi​(long v)
      Creates an int from a long, using the high order bits.
      static int extractLo​(long v)
      Creates an int from a long, using the low order bits.
      private static int getInt​(byte[] input, int index)
      Gets the int from the buffer starting at the given position.
      private static long getLong​(byte[] input, int index)
      Gets the long from the buffer starting at the given position.
      static boolean makeBoolean​(int v)
      Deprecated.
      Since version 1.2.
      static boolean makeBoolean​(long v)
      Deprecated.
      Since version 1.2.
      static byte[] makeByteArray​(int v)
      Splits an int into 4 bytes.
      static byte[] makeByteArray​(int[] input)
      Splits an array of int values into a sequence of bytes.
      static byte[] makeByteArray​(long v)
      Splits a long into 8 bytes.
      static byte[] makeByteArray​(long[] input)
      Splits an array of long values into a sequence of bytes.
      static double makeDouble​(int v, int w)
      Creates a double from two int values.
      static double makeDouble​(long v)
      Creates a double from a long value.
      static float makeFloat​(int v)
      Creates a float from an int value.
      static int makeInt​(byte[] input)
      Creates an int from 4 bytes.
      static int makeInt​(long v)
      Deprecated.
      Since version 1.2.
      static int[] makeIntArray​(byte[] input)
      Creates an array of int values from a sequence of bytes.
      static long makeLong​(byte[] input)
      Creates a long from 8 bytes.
      static long makeLong​(int v, int w)
      Creates a long from two int values.
      static long[] makeLongArray​(byte[] input)
      Creates an array of long values from a sequence of bytes.
      private static void putInt​(int v, byte[] buffer, int index)
      Puts the int into the buffer starting at the given position.
      private static void putLong​(long v, byte[] buffer, int index)
      Puts the long into the buffer starting at the given position.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • FLOAT_MULTIPLIER

        private static final float FLOAT_MULTIPLIER
        The multiplier to convert the least significant 24-bits of an int to a float. See makeFloat(int).

        This is equivalent to 1.0f / (1 << 24).

        See Also:
        Constant Field Values

      • LONG_LOWEST_BYTE_MASK

        private static final long LONG_LOWEST_BYTE_MASK
        Lowest byte mask.
        See Also:
        Constant Field Values

      • LONG_SIZE

        private static final int LONG_SIZE
        Number of bytes in a long.
        See Also:
        Constant Field Values

      • INT_LOWEST_BYTE_MASK

        private static final int INT_LOWEST_BYTE_MASK
        Lowest byte mask.
        See Also:
        Constant Field Values

    • Constructor Detail

      • NumberFactory

        private NumberFactory()
        Class contains only static methods.

    • Method Detail

      • makeBoolean

        @Deprecated
public static boolean makeBoolean​(int v)
        Deprecated.
        Since version 1.2. Method has become obsolete following RNG-57.
        Creates a boolean from an int value.
        Parameters:
        v - Number.
        Returns:
        a boolean.

      • makeBoolean

        @Deprecated
public static boolean makeBoolean​(long v)
        Deprecated.
        Since version 1.2. Method has become obsolete following RNG-57.
        Creates a boolean from a long value.
        Parameters:
        v - Number.
        Returns:
        a boolean.

      • makeDouble

        public static double makeDouble​(long v)
        Creates a double from a long value.
        Parameters:
        v - Number.
        Returns:
        a double value in the interval [0, 1].

      • makeDouble

        public static double makeDouble​(int v,
                                int w)
        Creates a double from two int values.
        Parameters:
        v - Number (high order bits).
        w - Number (low order bits).
        Returns:
        a double value in the interval [0, 1].

      • makeFloat

        public static float makeFloat​(int v)
        Creates a float from an int value.
        Parameters:
        v - Number.
        Returns:
        a float value in the interval [0, 1].

      • makeLong

        public static long makeLong​(int v,
                            int w)
        Creates a long from two int values.
        Parameters:
        v - Number (high order bits).
        w - Number (low order bits).
        Returns:
        a long value.

      • makeInt

        @Deprecated
public static int makeInt​(long v)
        Deprecated.
        Since version 1.2. Method has become obsolete following RNG-57.
        Creates an int from a long.
        Parameters:
        v - Number.
        Returns:
        an int value made from the "xor" of the high order bits and low order bits of v.

      • extractHi

        public static int extractHi​(long v)
        Creates an int from a long, using the high order bits.

        The returned value is such that if

        
  vL = extractLo(v);
  vH = extractHi(v);

        then v is equal to makeLong(vH, vL).

        Parameters:
        v - Number.
        Returns:
        an int value made from the most significant bits of v.

      • extractLo

        public static int extractLo​(long v)
        Creates an int from a long, using the low order bits.

        The returned value is such that if

        
  vL = extractLo(v);
  vH = extractHi(v);

        then v is equal to makeLong(vH, vL).

        Parameters:
        v - Number.
        Returns:
        an int value made from the least significant bits of v.

      • makeByteArray

        public static byte[] makeByteArray​(long v)
        Splits a long into 8 bytes.
        Parameters:
        v - Value.
        Returns:
        the bytes that compose the given value (least-significant byte first).

      • putLong

        private static void putLong​(long v,
                            byte[] buffer,
                            int index)
        Puts the long into the buffer starting at the given position. Adds 8 bytes (least-significant first).
        Parameters:
        v - Value.
        buffer - the buffer.
        index - the index.

      • makeLong

        public static long makeLong​(byte[] input)
        Creates a long from 8 bytes.
        Parameters:
        input - Input.
        Returns:
        the value that correspond to the given bytes assuming that the order is in increasing byte significance (i.e. the first byte in the array is the least-significant).
        Throws:
        java.lang.IllegalArgumentException - if input.length != 8.

      • getLong

        private static long getLong​(byte[] input,
                            int index)
        Gets the long from the buffer starting at the given position. Uses 8 bytes (least-significant first).
        Parameters:
        input - the input bytes.
        index - the index.
        Returns:
        the value that correspond to the given bytes assuming that the order is in increasing byte significance (i.e. the first byte in the array is the least-significant).

      • makeByteArray

        public static byte[] makeByteArray​(long[] input)
        Splits an array of long values into a sequence of bytes. This method calls makeByteArray(long) for each element of the input.
        Parameters:
        input - Input.
        Returns:
        an array of bytes.

      • makeLongArray

        public static long[] makeLongArray​(byte[] input)
        Creates an array of long values from a sequence of bytes. This method calls makeLong(byte[]) for each subsequence of 8 bytes.
        Parameters:
        input - Input.
        Returns:
        an array of long.
        Throws:
        java.lang.IllegalArgumentException - if input.length is not a multiple of 8.

      • makeByteArray

        public static byte[] makeByteArray​(int v)
        Splits an int into 4 bytes.
        Parameters:
        v - Value.
        Returns:
        the bytes that compose the given value (least-significant byte first).

      • putInt

        private static void putInt​(int v,
                           byte[] buffer,
                           int index)
        Puts the int into the buffer starting at the given position. Adds 4 bytes (least-significant first).
        Parameters:
        v - the value.
        buffer - the buffer.
        index - the index.

      • makeInt

        public static int makeInt​(byte[] input)
        Creates an int from 4 bytes.
        Parameters:
        input - Input.
        Returns:
        the value that correspond to the given bytes assuming that the order is in increasing byte significance (i.e. the first byte in the array is the least-significant).
        Throws:
        java.lang.IllegalArgumentException - if input.length != 4.

      • getInt

        private static int getInt​(byte[] input,
                          int index)
        Gets the int from the buffer starting at the given position. Uses 4 bytes (least-significant first).
        Parameters:
        input - the input bytes.
        index - the index.
        Returns:
        the value that correspond to the given bytes assuming that the order is in increasing byte significance (i.e. the first byte in the array is the least-significant).

      • makeByteArray

        public static byte[] makeByteArray​(int[] input)
        Splits an array of int values into a sequence of bytes. This method calls makeByteArray(int) for each element of the input.
        Parameters:
        input - Input.
        Returns:
        an array of bytes.

      • makeIntArray

        public static int[] makeIntArray​(byte[] input)
        Creates an array of int values from a sequence of bytes. This method calls makeInt(byte[]) for each subsequence of 4 bytes.
        Parameters:
        input - Input. Length must be a multiple of 4.
        Returns:
        an array of int.
        Throws:
        java.lang.IllegalArgumentException - if input.length is not a multiple of 4.

      • checkSize

        private static void checkSize​(int expected,
                              int actual)
        Parameters:
        expected - Expected value.
        actual - Actual value.
        Throws:
        java.lang.IllegalArgumentException - if expected != actual.