Package org.apache.derby.iapi.services.io

Class CompressedNumber

  • public abstract class CompressedNumber
extends java.lang.Object
    Static methods to write and read compressed forms of numbers to DataOut and DataIn interfaces. Format written is platform independent like the Data* interfaces and must remain fixed once a product is shipped. If a different format is required then write a new set of methods, e.g. writeInt2. The formats defined by stored format identifiers are implicitly dependent on these formats not changing.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static int readInt​(byte[] data, int offset)  
      static int readInt​(java.io.DataInput in)
      Read an integer previously written by writeInt().
      static int readInt​(java.io.InputStream in)
      Read an integer previously written by writeInt().
      static long readLong​(byte[] data, int offset)  
      static long readLong​(java.io.DataInput in)
      Read a long previously written by writeLong().
      static long readLong​(java.io.InputStream in)
      Read a long previously written by writeLong().
      static int sizeInt​(int value)
      Return the number of bytes that would be written by a writeInt call
      static int sizeLong​(long value)  
      static int writeInt​(java.io.DataOutput out, int value)
      Write a compressed integer only supporting signed values.
      static int writeInt​(java.io.OutputStream out, int value)
      Write a compressed integer directly to an OutputStream.
      static int writeLong​(java.io.DataOutput out, long value)
      Write a compressed long only supporting signed values.
      static int writeLong​(java.io.OutputStream out, long value)
      Write a compressed integer only supporting signed values.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • CompressedNumber

        public CompressedNumber()

    • Method Detail

      • writeInt

        public static final int writeInt​(java.io.DataOutput out,
                                 int value)
                          throws java.io.IOException
        Write a compressed integer only supporting signed values. Formats are (with x representing value bits): 
                        1 Byte - 00xxxxxx                              Represents the value <= 63 (0x3f)
                2 Byte - 01xxxxxx xxxxxxxx                     Represents the value > 63 && <= 16383 (0x3fff)
                4 byte - 1xxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx   Represents the value > 16383 && <= MAX_INT
        Throws:
        java.io.IOException - value is negative or an exception was thrown by a method on out.

      • writeInt

        public static final int writeInt​(java.io.OutputStream out,
                                 int value)
                          throws java.io.IOException
        Write a compressed integer directly to an OutputStream.
        Throws:
        java.io.IOException - an exception was thrown by a method on in.

      • readInt

        public static final int readInt​(java.io.DataInput in)
                         throws java.io.IOException
        Read an integer previously written by writeInt().
        Throws:
        java.io.IOException - an exception was thrown by a method on in.

      • readInt

        public static final int readInt​(java.io.InputStream in)
                         throws java.io.IOException
        Read an integer previously written by writeInt().
        Throws:
        java.io.IOException - an exception was thrown by a method on in.

      • readInt

        public static final int readInt​(byte[] data,
                                int offset)

      • sizeInt

        public static final int sizeInt​(int value)
        Return the number of bytes that would be written by a writeInt call

      • writeLong

        public static final int writeLong​(java.io.DataOutput out,
                                  long value)
                           throws java.io.IOException
        Write a compressed long only supporting signed values. Formats are (with x representing value bits): 
                        2 byte - 00xxxxxx xxxxxxxx                     Represents the value <= 16383 (0x3fff)
                4 byte - 01xxxxxx xxxxxxxx xxxxxxxx xxxxxxxx   Represents the value > 16383  && <= 0x3fffffff
                8 byte - 1xxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx   Represents the value > 0x3fffffff && <= MAX_LONG
        Throws:
        java.io.IOException - value is negative or an exception was thrown by a method on out.

      • writeLong

        public static final int writeLong​(java.io.OutputStream out,
                                  long value)
                           throws java.io.IOException
        Write a compressed integer only supporting signed values.
        Throws:
        java.io.IOException - value is negative or an exception was thrown by a method on out.

      • readLong

        public static final long readLong​(java.io.DataInput in)
                           throws java.io.IOException
        Read a long previously written by writeLong().
        Throws:
        java.io.IOException - an exception was thrown by a method on in.

      • readLong

        public static final long readLong​(java.io.InputStream in)
                           throws java.io.IOException
        Read a long previously written by writeLong().
        Throws:
        java.io.IOException - an exception was thrown by a method on in.

      • readLong

        public static final long readLong​(byte[] data,
                                  int offset)

      • sizeLong

        public static final int sizeLong​(long value)