Package org.xbill.DNS

Class DNSInput

java.lang.Object
org.xbill.DNS.DNSInput
public class DNSInput extends Object
A class for parsing DNS messages.
Author:
Brian Wellington

  • Constructor Summary

    Constructors
    Constructor
    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
    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 Details

    • 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 Details

    • 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.