Package org.apache.drill.exec.util

Class ByteBufUtil.HadoopWritables

java.lang.Object
org.apache.drill.exec.util.ByteBufUtil.HadoopWritables
Enclosing class:
ByteBufUtil
public static class ByteBufUtil.HadoopWritables extends Object
Modeled after org.apache.hadoop.io.WritableUtils. We copy the code to avoid wrapping DrillBuf to/from DataInput.

  • Constructor Summary

    Constructors
    Constructor
    Description
    HadoopWritables()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    decodeVIntSize(byte value)
    Parse the first byte of a vint/vlong to determine the number of bytes
    static int
    getVIntSize(long i)
    Get the encoded length if an integer is stored in a variable-length format
    static boolean
    isNegativeVInt(byte value)
    Given the first byte of a vint/vlong, determine the sign
    static int
    readVInt(DrillBuf buffer, int start, int end)
    Reads a zero-compressed encoded integer from input stream and returns it.
    static long
    readVLong(DrillBuf buffer, int start, int end)
    Reads a zero-compressed encoded long from input stream and returns it.
    static void
    writeVInt(DrillBuf buffer, int start, int end, int i)
    Serializes an integer to a binary stream with zero-compressed encoding.
    static void
    writeVLong(DrillBuf buffer, int start, int end, long i)
    Serializes a long to a binary stream with zero-compressed encoding.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • HadoopWritables

      public HadoopWritables()

  • Method Details

    • writeVInt

      public static void writeVInt(DrillBuf buffer, int start, int end, int i)
      Serializes an integer to a binary stream with zero-compressed encoding. For -120 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the integer is positive or negative, and the number of bytes that follow. If the first byte value v is between -121 and -124, the following integer is positive, with number of bytes that follow are -(v+120). If the first byte value v is between -125 and -128, the following integer is negative, with number of bytes that follow are -(v+124). Bytes are stored in the high-non-zero-byte-first order.
      Parameters:
      buffer - DrillBuf to read from
      i - Integer to be serialized

    • writeVLong

      public static void writeVLong(DrillBuf buffer, int start, int end, long i)
      Serializes a long to a binary stream with zero-compressed encoding. For -112 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the long is positive or negative, and the number of bytes that follow. If the first byte value v is between -113 and -120, the following long is positive, with number of bytes that follow are -(v+112). If the first byte value v is between -121 and -128, the following long is negative, with number of bytes that follow are -(v+120). Bytes are stored in the high-non-zero-byte-first order.
      Parameters:
      buffer - DrillBuf to write to
      i - Long to be serialized

    • readVInt

      public static int readVInt(DrillBuf buffer, int start, int end)
      Reads a zero-compressed encoded integer from input stream and returns it.
      Parameters:
      buffer - DrillBuf to read from
      Returns:
      deserialized integer from stream.

    • readVLong

      public static long readVLong(DrillBuf buffer, int start, int end)
      Reads a zero-compressed encoded long from input stream and returns it.
      Parameters:
      buffer - DrillBuf to read from
      Returns:
      deserialized long from stream.

    • decodeVIntSize

      public static int decodeVIntSize(byte value)
      Parse the first byte of a vint/vlong to determine the number of bytes
      Parameters:
      value - the first byte of the vint/vlong
      Returns:
      the total number of bytes (1 to 9)

    • getVIntSize

      public static int getVIntSize(long i)
      Get the encoded length if an integer is stored in a variable-length format
      Returns:
      the encoded length

    • isNegativeVInt

      public static boolean isNegativeVInt(byte value)
      Given the first byte of a vint/vlong, determine the sign
      Parameters:
      value - the first byte
      Returns:
      is the value negative