org.xbill.DNS

Class DNSInput

java.lang.Object

org.xbill.DNS.DNSInput

public class DNSInput
extends Object

An class for parsing DNS messages.

Author:

Brian Wellington

Constructor Summary

Constructors

Constructor and Description
DNSInput(byte[] input) Creates a new DNSInput
DNSInput(ByteBuffer byteBuffer) Creates a new DNSInput from the given ByteBuffer

Method Summary

Modifier and Type	Method and Description
void	clearActive() Clears the active region of the string.
int	current() Returns the current position.
void	jump(int index) Resets the current position of the input stream to the specified index, and clears the active region.
byte[]	readByteArray() Reads a byte array consisting of the remainder of the stream (or the active region, if one is set.
void	readByteArray(byte[] b, int off, int len) Reads a byte array of a specified length from the stream into an existing array.
byte[]	readByteArray(int len) Reads a byte array of a specified length from the stream.
byte[]	readCountedString() Reads a counted string from the stream.
int	readU16() Reads an unsigned 16 bit value from the stream, as an int.
long	readU32() Reads an unsigned 32 bit value from the stream, as a long.
int	readU8() Reads an unsigned 8 bit value from the stream, as an int.
int	remaining() Returns the number of bytes that can be read from this stream before reaching the end.
void	restore() Restores the input stream to its state before the call to save().
void	restoreActive(int pos) Restores the previously set active region.
void	save() Saves the current state of the input stream.
int	saveActive() Returns the position of the end of the current active region.
void	setActive(int len) Marks the following bytes in the stream as active.

Methods inherited from class java.lang.Object

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

Constructor Detail

DNSInput

public DNSInput(byte[] input)

Creates a new DNSInput

Parameters:

input - The byte array to read from

DNSInput

public DNSInput(ByteBuffer byteBuffer)

Creates a new DNSInput from the given ByteBuffer

Parameters:

byteBuffer - The ByteBuffer

Method Detail

current

public int current()

Returns the current position.

remaining

public int remaining()

Returns the number of bytes that can be read from this stream before reaching the end.

setActive

public void setActive(int len)

Marks the following bytes in the stream as active.

Parameters:

len - The number of bytes in the active region.

Throws:

IllegalArgumentException - The number of bytes in the active region is longer than the remainder of the input.

clearActive

public void clearActive()

Clears the active region of the string. Further operations are not restricted to part of the input.

saveActive

public int saveActive()

Returns the position of the end of the current active region.

restoreActive

public void restoreActive(int pos)

Restores the previously set active region. This differs from setActive() in that restoreActive() takes an absolute position, and setActive takes an offset from the current location.

Parameters:

pos - The end of the active region.

jump

public void jump(int index)

Resets the current position of the input stream to the specified index, and clears the active region.

Parameters:

index - The position to continue parsing at.

Throws:

IllegalArgumentException - The index is not within the input.

save

public void save()

Saves the current state of the input stream. Both the current position and the end of the active region are saved.

Throws:

IllegalArgumentException - The index is not within the input.

restore

public void restore()

Restores the input stream to its state before the call to save().

readU8

public int readU8()
           throws WireParseException

Reads an unsigned 8 bit value from the stream, as an int.

Returns:

An unsigned 8 bit value.

Throws:

WireParseException - The end of the stream was reached.

readU16

public int readU16()
            throws WireParseException

Reads an unsigned 16 bit value from the stream, as an int.

Returns:

An unsigned 16 bit value.

Throws:

WireParseException - The end of the stream was reached.

readU32

public long readU32()
             throws WireParseException

Reads an unsigned 32 bit value from the stream, as a long.

Returns:

An unsigned 32 bit value.

Throws:

WireParseException - The end of the stream was reached.

readByteArray

public void readByteArray(byte[] b,
                          int off,
                          int len)
                   throws WireParseException

Reads a byte array of a specified length from the stream into an existing array.

Parameters:

b - The array to read into.

off - The offset of the array to start copying data into.

len - The number of bytes to copy.

Throws:

WireParseException - The end of the stream was reached.

readByteArray

public byte[] readByteArray(int len)
                     throws WireParseException

Reads a byte array of a specified length from the stream.

Returns:

The byte array.

Throws:

WireParseException - The end of the stream was reached.

readByteArray

public byte[] readByteArray()

Reads a byte array consisting of the remainder of the stream (or the active region, if one is set.

Returns:

The byte array.

readCountedString

public byte[] readCountedString()
                         throws WireParseException

Reads a counted string from the stream. A counted string is a one byte value indicating string length, followed by bytes of data.

Returns:

A byte array containing the string.

Throws:

WireParseException - The end of the stream was reached.