org.json.zip

Class BitInputStream

java.lang.Object

org.json.zip.BitInputStream

All Implemented Interfaces:

BitReader

public class BitInputStream
extends Object
implements BitReader

This is a big endian bit reader. It reads its bits from an InputStream.

Version:

2013-04-18

Constructor Summary

Constructors

Constructor and Description
BitInputStream(InputStream in) Make a BitReader from an InputStream.
BitInputStream(InputStream in, int firstByte) Make a BitReader.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	bit() Read one bit.
long	nrBits() Get the number of bits that have been read from this BitInputStream.
boolean	pad(int factor) Check that the rest of the block has been padded with zeroes.
int	read(int width) Read some bits.

Methods inherited from class java.lang.Object

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

Constructor Detail

BitInputStream

public BitInputStream(InputStream in)

Make a BitReader from an InputStream. The BitReader will take bytes from the InputStream and unpack them into bits.

Parameters:

in - An InputStream.

BitInputStream

public BitInputStream(InputStream in,
              int firstByte)

Make a BitReader. The first byte is passed in explicitly, the remaining bytes are obtained from the InputStream. This makes it possible to look at the first byte of a stream before deciding that it should be read as bits.

Parameters:

in - An InputStream

firstByte - The first byte, which was probably read from in.

Method Detail

bit

public boolean bit()
            throws IOException

Read one bit.

Specified by:

bit in interface BitReader

Returns:

true if it is a 1 bit.

Throws:

IOException

nrBits

public long nrBits()

Get the number of bits that have been read from this BitInputStream. This includes pad bits that have been skipped, but might not include bytes that have been read from the underlying InputStream that have not yet been delivered as bits.

Specified by:

nrBits in interface BitReader

Returns:

The number of bits read so far.

pad

public boolean pad(int factor)
            throws IOException

Check that the rest of the block has been padded with zeroes.

Specified by:

pad in interface BitReader

Parameters:

factor - The size of the block to pad. This will typically be 8, 16, 32, 64, 128, 256, etc.

Returns:

true if the block was zero padded, or false if the the padding contains any one bits.

Throws:

IOException

read

public int read(int width)
         throws IOException

Read some bits.

Specified by:

read in interface BitReader

Parameters:

width - The number of bits to read. (0..32)

Returns:

the bits

Throws:

IOException