org.mapdb

Class DataIO

java.lang.Object

org.mapdb.DataIO

public final class DataIO
extends Object

Various IO classes and utilities..

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DataIO.DataInputByteArray DataInput on top of byte[]
static class	DataIO.DataInputByteBuffer Wraps ByteBuffer and provides DataInput
static interface	DataIO.DataInputInternal Give access to internal byte[] or ByteBuffer in DataInput2..
static class	DataIO.DataInputToStream Wraps DataInput into InputStream
static class	DataIO.DataOutputByteArray Provides DataOutput implementation on top of growable byte[] ByteArrayOutputStream is not used as it requires byte[] copying
static class	DataIO.HeartbeatFileLock File locking mechanism.

Field Summary

Fields

Modifier and Type	Field and Description
static long	PACK_LONG_RESULT_MASK

Method Summary

Methods

Modifier and Type	Method and Description
static long	fillLowBits(int bitCount)
static byte[]	fromHexa(String s) Converts hexadecimal string into binary data
static long	getLong(byte[] buf, int pos)
static long	getSixLong(byte[] buf, int pos)
static long	hash(byte[] buf, int off, int len, long seed) Calculates XXHash64 from given byte[] buffer.
static long	hash(char[] buf, int off, int len, long seed) Calculates XXHash64 from given char[] buffer.
static int	intHash(int h)
static int	longHash(long h)
static int	nextPowTwo(int a)
static long	nextPowTwo(long a)
static void	packInt(DataOutput out, int value) Pack int into an output stream.
static void	packIntBigger(DataOutput out, int value) Pack int into an output stream.
static void	packLong(DataOutput out, long value) Pack long into output.
static void	packLong(OutputStream out, long value) Pack long into output.
static int	packLongBidi(byte[] b, int pos, long value) Pack long into output.
static int	packLongSize(long value) Calculate how much bytes packed long consumes.
static void	packRecid(DataOutput out, long value) Pack RECID into output stream with 3 bit checksum.
static long	parity16Get(long i)
static long	parity16Set(long i)
static long	parity1Get(long i)
static long	parity1Set(long i)
static long	parity3Get(long i)
static long	parity3Set(long i)
static long	parity4Get(long i)
static long	parity4Set(long i)
static void	putLong(byte[] buf, int pos, long v)
static void	putSixLong(byte[] buf, int pos, long value)
static void	readFully(InputStream in, byte[] data)
static void	skipFully(InputStream in, long length)
static String	toHexa(byte[] bb) Converts binary array into its hexadecimal representation.
static int	unpackInt(DataInput is) Unpack int value from the input stream.
static long	unpackLong(DataInput in) Unpack long value from the input stream.
static long	unpackLong(InputStream in) Unpack long value from the input stream.
static long	unpackLongBidi(byte[] b, int pos) Unpack long value.
static long	unpackLongBidiReverse(byte[] bb, int pos, int limit)
static long	unpackRecid(DataInput in) Unpack RECID value from the input stream with 3 bit checksum.

Methods inherited from class java.lang.Object

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

Field Detail

PACK_LONG_RESULT_MASK

public static final long PACK_LONG_RESULT_MASK

See Also:

Constant Field Values

Method Detail

unpackInt

public static int unpackInt(DataInput is)
                     throws IOException

Unpack int value from the input stream.

Parameters:

is - The input stream.

Returns:

The long value.

Throws:

IOException - in case of IO error

unpackLong

public static long unpackLong(DataInput in)
                       throws IOException

Unpack long value from the input stream.

Parameters:

in - The input stream.

Returns:

The long value.

Throws:

IOException - in case of IO error

unpackLong

public static long unpackLong(InputStream in)
                       throws IOException

Unpack long value from the input stream.

Parameters:

in - The input stream.

Returns:

The long value.

Throws:

IOException - in case of IO error

packLong

public static void packLong(DataOutput out,
            long value)
                     throws IOException

Pack long into output. It will occupy 1-10 bytes depending on value (lower values occupy smaller space)

Parameters:

out - DataOutput to put value into

value - to be serialized, must be non-negative

Throws:

IOException - in case of IO error

packLong

public static void packLong(OutputStream out,
            long value)
                     throws IOException

Pack long into output. It will occupy 1-10 bytes depending on value (lower values occupy smaller space)

Parameters:

out - OutputStream to put value into

value - to be serialized, must be non-negative

Throws:

IOException - in case of IO error

packLongSize

public static int packLongSize(long value)

Calculate how much bytes packed long consumes.

Parameters:

value - to calculate

Returns:

number of bytes used in packed form

unpackRecid

public static long unpackRecid(DataInput in)
                        throws IOException

Unpack RECID value from the input stream with 3 bit checksum.

Parameters:

in - The input stream.

Returns:

The long value.

Throws:

IOException - in case of IO error

packRecid

public static void packRecid(DataOutput out,
             long value)
                      throws IOException

Pack RECID into output stream with 3 bit checksum. It will occupy 1-10 bytes depending on value (lower values occupy smaller space)

Parameters:

out - DataOutput to put value into

value - to be serialized, must be non-negative

Throws:

IOException - in case of IO error

packInt

public static void packInt(DataOutput out,
           int value)
                    throws IOException

Pack int into an output stream. It will occupy 1-5 bytes depending on value (lower values occupy smaller space)

Parameters:

out - DataOutput to put value into

value - to be serialized, must be non-negative

Throws:

IOException - in case of IO error

packIntBigger

public static void packIntBigger(DataOutput out,
                 int value)
                          throws IOException

Pack int into an output stream. It will occupy 1-5 bytes depending on value (lower values occupy smaller space) This method is same as packInt(DataOutput, int), but is optimized for values larger than 127. Usually it is recids.

Parameters:

out - DataOutput to put value into

value - to be serialized, must be non-negative

Throws:

IOException - in case of IO error

longHash

public static int longHash(long h)

intHash

public static int intHash(int h)

packLongBidi

public static int packLongBidi(byte[] b,
               int pos,
               long value)

Pack long into output. It will occupy 1-10 bytes depending on value (lower values occupy smaller space)

Parameters:

b - byte[] to put value into

pos - array index where value will start

value - to be serialized, must be non-negative

Returns:

number of bytes written

unpackLongBidi

public static long unpackLongBidi(byte[] b,
                  int pos)

Unpack long value. Highest 4 bits sed to indicate number of bytes read. One can use result & DataIO.PACK_LONG_RESULT_MASK to remove size. This method uses reverse bit flag, which is not compatible with other methods.

Parameters:

b - byte[] to get data from

pos - position to get data from

Returns:

long value with highest 4 bits used to indicate number of bytes read

unpackLongBidiReverse

public static long unpackLongBidiReverse(byte[] bb,
                         int pos,
                         int limit)

getLong

public static long getLong(byte[] buf,
           int pos)

putLong

public static void putLong(byte[] buf,
           int pos,
           long v)

getSixLong

public static long getSixLong(byte[] buf,
              int pos)

putSixLong

public static void putSixLong(byte[] buf,
              int pos,
              long value)

nextPowTwo

public static long nextPowTwo(long a)

nextPowTwo

public static int nextPowTwo(int a)

readFully

public static void readFully(InputStream in,
             byte[] data)
                      throws IOException

Throws:

IOException

skipFully

public static void skipFully(InputStream in,
             long length)
                      throws IOException

Throws:

IOException

fillLowBits

public static long fillLowBits(int bitCount)

parity1Set

public static long parity1Set(long i)

parity1Get

public static long parity1Get(long i)

parity3Set

public static long parity3Set(long i)

parity3Get

public static long parity3Get(long i)

parity4Set

public static long parity4Set(long i)

parity4Get

public static long parity4Get(long i)

parity16Set

public static long parity16Set(long i)

parity16Get

public static long parity16Get(long i)

toHexa

public static String toHexa(byte[] bb)

Converts binary array into its hexadecimal representation.

Parameters:

bb - binary data

Returns:

hexadecimal string

fromHexa

public static byte[] fromHexa(String s)

Converts hexadecimal string into binary data

Parameters:

s - hexadecimal string

Returns:

binary data

Throws:

NumberFormatException - in case of string format error

hash

public static long hash(byte[] buf,
        int off,
        int len,
        long seed)

Calculates XXHash64 from given byte[] buffer.

This code comes from LZ4-Java created by Adrien Grand.

Parameters:

buf - to calculate hash from

off - offset to start calculation from

len - length of data to calculate hash

seed - hash seed

Returns:

XXHash.

hash

public static long hash(char[] buf,
        int off,
        int len,
        long seed)

Calculates XXHash64 from given char[] buffer.

This code comes from LZ4-Java created by Adrien Grand.

Parameters:

buf - to calculate hash from

off - offset to start calculation from

len - length of data to calculate hash

seed - hash seed

Returns:

XXHash.