Package org.opendaylight.openflowplugin.libraries.liblldp

Class BitBufferHelper

  • public abstract class BitBufferHelper
extends Object
    BitBufferHelper class that provides utility methods to - fetch specific bits from a serialized stream of bits - convert bits to primitive data type - like short, int, long - store bits in specified location in stream of bits - convert primitive data types to stream of bits.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static long BYTE_MASK  

    • Constructor Summary

      Constructors 
      Constructor Description
      BitBufferHelper()  

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static void checkExceptions​(byte[] data, int startOffset, int numBits)
      Checks for overflow and underflow exceptions.
      static byte @NonNull [] getBits​(byte[] data, int startOffset, int numBits)
      Reads the specified number of bits from the passed byte array starting to read from the specified offset The bits read are stored in a byte array which size is dictated by the number of bits to be stored.
      static byte getByte​(byte[] data)
      Returns the first byte from the byte array.
      static int getInt​(byte[] data)
      Returns the int value for the byte array passed.
      static int getInt​(byte[] data, int numBits)
      Returns the int value for the last numBits of the byte array passed.
      static long getLong​(byte[] data)
      Returns the long value for the byte array passed.
      static long getLong​(byte[] data, int numBits)
      Returns the long value for the last numBits of the byte array passed.
      static int getLSBMask​(int numBits)
      Returns numBits 1's in the LSB position.
      static int getMSBMask​(int numBits)
      Returns numBits 1's in the MSB position.
      static short getShort​(byte[] data)
      Returns the short value for the byte array passed.
      static short getShort​(byte[] data, int numBits)
      Returns the short value for the last numBits of the byte array passed.
      static void setBytes​(byte[] data, byte[] input, int startOffset, int numBits)
      Deprecated.
      Use copyBitsFromLsb(byte[], byte[], int, int) instead.
      static byte[] shiftBitsToLSB​(byte[] inputBytes, int numBits)
      It aligns the first numBits bits to the right end of the byte array preceding them with numBits % 8 zero bits.
      static byte[] shiftBitsToMSB​(byte[] inputBytes, int numBits)
      Takes an LSB aligned byte array and returned the LSB numBits in a MSB aligned byte array.
      static byte[] toByteArray​(Number input)
      Accepts a number as input and returns its value in byte form in LSB aligned form example: input = 5000 [1001110001000] bytes = 19, -120 [00010011] [10001000].
      static byte[] toByteArray​(Number input, int numBits)
      Accepts a number as input and returns its value in byte form in MSB aligned form example: input = 5000 [1001110001000] bytes = -114, 64 [10011100] [01000000].
      static long toNumber​(byte[] array)
      Returns the numerical value of the byte array passed.
      static long toNumber​(byte[] array, int numBits)
      Returns the numerical value of the last numBits (LSB bits) of the byte array passed.

    • Constructor Detail

      • BitBufferHelper

        public BitBufferHelper()

    • Method Detail

      • getByte

        public static byte getByte​(byte[] data)
        Returns the first byte from the byte array.
        Returns:
        byte value

      • getShort

        public static short getShort​(byte[] data)
        Returns the short value for the byte array passed. Size of byte array is restricted to Short.SIZE
        Returns:
        short value

      • getShort

        public static short getShort​(byte[] data,
                             int numBits)
        Returns the short value for the last numBits of the byte array passed. Size of numBits is restricted to Short.SIZE
        Returns:
        short - the short value of byte array

      • getInt

        public static int getInt​(byte[] data)
        Returns the int value for the byte array passed. Size of byte array is restricted to Integer.SIZE
        Returns:
        int - the integer value of byte array

      • getInt

        public static int getInt​(byte[] data,
                         int numBits)
        Returns the int value for the last numBits of the byte array passed. Size of numBits is restricted to Integer.SIZE
        Returns:
        int - the integer value of byte array

      • getLong

        public static long getLong​(byte[] data)
        Returns the long value for the byte array passed. Size of byte array is restricted to Long.SIZE
        Returns:
        long - the integer value of byte array

      • getLong

        public static long getLong​(byte[] data,
                           int numBits)
        Returns the long value for the last numBits of the byte array passed. Size of numBits is restricted to Long.SIZE
        Returns:
        long - the integer value of byte array

      • getBits

        public static byte @NonNull [] getBits​(byte[] data,
                                       int startOffset,
                                       int numBits)
                                throws BufferException
        Reads the specified number of bits from the passed byte array starting to read from the specified offset The bits read are stored in a byte array which size is dictated by the number of bits to be stored. The bits are stored in the byte array LSB aligned.

        Ex. Read 7 bits at offset 10 0 9 10 16 17 0101000010 | 0000101 | 1111001010010101011 will be returned as {0,0,0,0,0,1,0,1}

        Parameters:
        startOffset - - offset to start fetching bits from data from
        numBits - - number of bits to be fetched from data
        Returns:
        byte [] - LSB aligned bits
        Throws:
        BufferException - when the startOffset and numBits parameters are not congruent with the data buffer size

      • setBytes

        @Deprecated
public static void setBytes​(byte[] data,
                            byte[] input,
                            int startOffset,
                            int numBits)
                     throws BufferException
        Deprecated.
        Use copyBitsFromLsb(byte[], byte[], int, int) instead.
        Bits are expected to be stored in the input byte array from LSB.
        Parameters:
        data - to set the input byte
        input - bytes to be inserted
        startOffset - offset of data[] to start inserting byte from
        numBits - number of bits of input to be inserted into data[]
        Throws:
        BufferException - when the startOffset and numBits parameters are not congruent with data and input buffers' size

      • getMSBMask

        public static int getMSBMask​(int numBits)
        Returns numBits 1's in the MSB position.

      • getLSBMask

        public static int getLSBMask​(int numBits)
        Returns numBits 1's in the LSB position.

      • toNumber

        public static long toNumber​(byte[] array)
        Returns the numerical value of the byte array passed.
        Returns:
        long - numerical value of byte array passed

      • toNumber

        public static long toNumber​(byte[] array,
                            int numBits)
        Returns the numerical value of the last numBits (LSB bits) of the byte array passed.
        Returns:
        long - numerical value of byte array passed

      • toByteArray

        public static byte[] toByteArray​(Number input)
        Accepts a number as input and returns its value in byte form in LSB aligned form example: input = 5000 [1001110001000] bytes = 19, -120 [00010011] [10001000].

      • toByteArray

        public static byte[] toByteArray​(Number input,
                                 int numBits)
        Accepts a number as input and returns its value in byte form in MSB aligned form example: input = 5000 [1001110001000] bytes = -114, 64 [10011100] [01000000].
        Parameters:
        numBits - - the number of bits to be returned
        Returns:
        byte[]

      • shiftBitsToMSB

        public static byte[] shiftBitsToMSB​(byte[] inputBytes,
                                    int numBits)
        Takes an LSB aligned byte array and returned the LSB numBits in a MSB aligned byte array.

        It aligns the last numBits bits to the head of the byte array following them with numBits % 8 zero bits.

        Example: For inputbytes = [00000111][01110001] and numBits = 12 it returns: shiftedBytes = [01110111][00010000]

        Parameters:
        numBits - - number of bits to be left aligned
        Returns:
        byte[]

      • shiftBitsToLSB

        public static byte[] shiftBitsToLSB​(byte[] inputBytes,
                                    int numBits)
        It aligns the first numBits bits to the right end of the byte array preceding them with numBits % 8 zero bits.

        Example: For inputbytes = [01110111][00010000] and numBits = 12 it returns: shiftedBytes = [00000111][01110001]

        Parameters:
        inputBytes - input bytes
        numBits - - number of bits to be right aligned
        Returns:
        byte[]

      • checkExceptions

        public static void checkExceptions​(byte[] data,
                                   int startOffset,
                                   int numBits)
                            throws BufferException
        Checks for overflow and underflow exceptions.
        Throws:
        BufferException - when the startOffset and numBits parameters are not congruent with the data buffer's size