Package ucar.nc2.iosp

Class BitReader

java.lang.Object

ucar.nc2.iosp.BitReader

public class BitReader
extends Object

Helper for reading data that has been bit packed.

Since:

Apr 7, 2008

Constructor Summary

Constructors

Constructor	Description
BitReader(byte[] test)
BitReader(RandomAccessFile raf, long startPos)	Constructor

Method Summary

Modifier and Type	Method	Description
long	bits2SInt(int nb)	Read the next nb bits and return an Signed Long .
long	bits2UInt(int nb)	Read the next nb bits and return an Unsigned Long .
static boolean	getBit(long decimal, int N)
long	getPos()
void	incrByte()	Go to the next byte in the stream
static long	setBit(long decimal, int N, boolean value)
void	setBitOffset(int bitOffset)	Position file at bitOffset from startPos

Methods inherited from class java.lang.Object

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

Constructor Detail

BitReader

public BitReader(byte[] test)

BitReader

public BitReader(RandomAccessFile raf,
                 long startPos)
          throws IOException

Constructor

Parameters:

raf - the RandomAccessFile

startPos - points to start of data in data section, in bytes

Throws:

IOException - on read error

Method Detail

incrByte

public void incrByte()

Go to the next byte in the stream

setBitOffset

public void setBitOffset(int bitOffset)
                  throws IOException

Position file at bitOffset from startPos

Parameters:

bitOffset - bit offset from starting position

Throws:

IOException - on io error

getPos

public long getPos()

bits2UInt

public long bits2UInt(int nb)
               throws IOException

Read the next nb bits and return an Unsigned Long .

Parameters:

nb - the number of bits to convert to int, must be 0 <= nb <= 64.

Returns:

result

Throws:

IOException - on read error

bits2SInt

public long bits2SInt(int nb)
               throws IOException

Read the next nb bits and return an Signed Long .

Parameters:

nb - the number of bits to convert to int, must be <= 64.

Returns:

result

Throws:

IOException - on read error

setBit

public static long setBit(long decimal,
                          int N,
                          boolean value)

getBit

public static boolean getBit(long decimal,
                             int N)