BitBufferHelper (liblldp 0.9.1-Lithium-SR1 API)

java.lang.Object
- org.opendaylight.controller.liblldp.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 and Description

static long ByteMask

protected static org.slf4j.Logger logger

Fields
Modifier and Type	Field and Description
`static long`	`ByteMask`
`protected static org.slf4j.Logger`	`logger`

Constructor Summary

Constructors
Constructor and Description

BitBufferHelper()

Constructors
Constructor and Description
`BitBufferHelper()`

Method Summary

Methods
Modifier and Type	Method and Description
`static void`	`checkExceptions(byte[] data, int startOffset, int numBits)` Checks for overflow and underflow exceptions
`static byte[]`	`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`	`insertBits(byte[] data, byte[] inputdataLSB, int startOffset, int numBits)` Insert in the data buffer at position dictated by the offset the number of bits specified from the input data byte array.
`static void`	`setByte(byte[] data, byte input, int startOffset, int numBits)` Bits are expected to be stored in the input byte array from LSB
`static void`	`setBytes(byte[] data, byte[] input, int startOffset, int numBits)` Bits are expected to be stored in the input byte array from LSB
`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)` It aligns the last numBits bits to the head of the byte array following them with numBits % 8 zero bits.
`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

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - logger
```
protected static final org.slf4j.Logger logger
```
  - ByteMask
```
public static final long ByteMask
```
    See Also:
    Constant Field Values
- Constructor Detail
  - BitBufferHelper
```
public BitBufferHelper()
```
- Method Detail
  - getByte
```
public static byte getByte(byte[] data)
```
    Returns the first byte from the byte array
    
    Parameters:
    byte[] - data
    
    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
    
    Parameters:
    byte[] - data
    
    Returns:
    short value
  - 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
    
    Parameters:
    byte[] - data
    
    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
    
    Parameters:
    byte[] - data
    
    Returns:
    long - the integer value of byte array
  - 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
    
    Parameters:
    byte[] - data
    int - - numBits
    
    Returns:
    short - the short 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
    
    Parameters:
    byte[] - data
    int - - numBits
    
    Returns:
    int - 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
    
    Parameters:
    byte[] - data
    int - - numBits
    
    Returns:
    long - the integer value of byte array
  - getBits
```
public static byte[] 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:
    byte[] - data
    int - startOffset - offset to start fetching bits from data from
    int - 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
  - setByte
```
public static void setByte(byte[] data,
           byte input,
           int startOffset,
           int numBits)
                    throws BufferException
```
    Bits are expected to be stored in the input byte array from LSB
    
    Parameters:
    byte[] - - data to set the input byte
    byte - - input byte 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 input, startOffset and numBits are not congruent with the data buffer size
  - setBytes
```
public static void setBytes(byte[] data,
            byte[] input,
            int startOffset,
            int numBits)
                     throws BufferException
```
    Bits are expected to be stored in the input byte array from LSB
    
    Parameters:
    byte[] - - data to set the input byte
    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
    
    Parameters:
    numBits -
    
    Returns:
  - getLSBMask
```
public static int getLSBMask(int numBits)
```
    Returns numBits 1's in the LSB position
    
    Parameters:
    numBits -
    
    Returns:
  - toNumber
```
public static long toNumber(byte[] array)
```
    Returns the numerical value of the byte array passed
    
    Parameters:
    byte[] - - array
    
    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
    
    Parameters:
    byte[] - - array
    int - - numBits
    
    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]
    
    Parameters:
    Number -
    
    Returns:
    byte[]
  - 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:
    Number - input
    int - numBits - the number of bits to be returned
    
    Returns:
    byte[]
  - shiftBitsToMSB
```
public static byte[] shiftBitsToMSB(byte[] inputBytes,
                    int numBits)
```
    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:
    byte[] - inputBytes
    int - 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:
    byte[] - inputBytes
    int - numBits - number of bits to be right aligned
    
    Returns:
    byte[]
  - insertBits
```
public static void insertBits(byte[] data,
              byte[] inputdataLSB,
              int startOffset,
              int numBits)
```
    Insert in the data buffer at position dictated by the offset the number of bits specified from the input data byte array. The input byte array has the bits stored starting from the LSB
    
    Parameters:
    byte[] - data
    byte[] - inputdata
    int - startOffset
    int - numBits
  - checkExceptions
```
public static void checkExceptions(byte[] data,
                   int startOffset,
                   int numBits)
                            throws BufferException
```
    Checks for overflow and underflow exceptions
    
    Parameters:
    data -
    startOffset -
    numBits -
    
    Throws:
    
    PacketException - when the startOffset and numBits parameters are not congruent with the data buffer's size
    
    BufferException

Class BitBufferHelper

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

logger

ByteMask

Constructor Detail

BitBufferHelper

Method Detail

getByte

getShort

getInt

getLong

getShort

getInt

getLong

getBits

setByte

setBytes

getMSBMask

getLSBMask

toNumber

toNumber

toByteArray

toByteArray

shiftBitsToMSB

shiftBitsToLSB

insertBits

checkExceptions