Package org.apache.cassandra.utils

Class ByteBufferUtil

java.lang.Object

org.apache.cassandra.utils.ByteBufferUtil

public class ByteBufferUtil
extends Object

Utility methods to make ByteBuffers less painful The following should illustrate the different ways byte buffers can be used public void testArrayOffet() { byte[] b = "test_slice_array".getBytes(); ByteBuffer bb = ByteBuffer.allocate(1024); assert bb.position() == 0; assert bb.limit() == 1024; assert bb.capacity() == 1024; bb.put(b); assert bb.position() == b.length; assert bb.remaining() == bb.limit() - bb.position(); ByteBuffer bb2 = bb.slice(); assert bb2.position() == 0; //slice should begin at other buffers current position assert bb2.arrayOffset() == bb.position(); //to match the position in the underlying array one needs to //track arrayOffset assert bb2.limit()+bb2.arrayOffset() == bb.limit(); assert bb2.remaining() == bb.remaining(); } }

Field Summary

Fields

Modifier and Type	Field	Description
static final ByteBuffer[]	EMPTY_ARRAY
static final ByteBuffer	EMPTY_BYTE_BUFFER
static final ByteBuffer	UNSET_BYTE_BUFFER	Represents an unset value in bound variables

Constructor Summary

Constructors

Constructor	Description
ByteBufferUtil()

Method Summary

Modifier and Type	Method	Description
static ByteBuffer	bytes(byte b)
static ByteBuffer	bytes(double d)
static ByteBuffer	bytes(float f)
static ByteBuffer	bytes(int i)
static ByteBuffer	bytes(long n)
static ByteBuffer	bytes(short s)
static ByteBuffer	bytes(String s)	Encode a String in a ByteBuffer using UTF_8.
static ByteBuffer	bytes(String s, Charset charset)	Encode a String in a ByteBuffer using the provided charset.
static ByteBuffer	bytes(InetAddress address)
static ByteBuffer	bytes(UUID uuid)
static ByteBuffer	bytes(TimeUUID uuid)
static String	bytesToHex(ByteBuffer bytes)
static boolean	canMinimize(ByteBuffer buf)
static boolean	canMinimize(ByteBuffer[] src)
static ByteBuffer	clone(ByteBuffer buffer)
static int	compare(byte[] o1, ByteBuffer o2)
static int	compare(byte[] o1, ByteBuffer o2, int s2, int l2)
static int	compare(ByteBuffer o1, byte[] o2)
static int	compare(ByteBuffer o1, int s1, int l1, byte[] o2)
static int	compareSubArrays(ByteBuffer bytes1, int offset1, ByteBuffer bytes2, int offset2, int length)	Compare two ByteBuffer at specified offsets for length.
static int	compareUnsigned(ByteBuffer o1, ByteBuffer o2)
static boolean	contains(ByteBuffer buffer, ByteBuffer subBuffer)	Check is the given buffer contains a given sub-buffer.
static void	copyBytes(ByteBuffer src, int srcPos, byte[] dst, int dstPos, int length)	Transfer bytes from a ByteBuffer to byte array.
static void	copyBytes(ByteBuffer src, int srcPos, ByteBuffer dst, int dstPos, int length)	Transfer bytes from one ByteBuffer to another.
static boolean	endsWith(ByteBuffer src, ByteBuffer suffix)
static ByteBuffer	ensureCapacity(ByteBuffer buf, int outputLength, boolean allowBufferResize)	Ensure buf is large enough for outputLength.
static ByteBuffer	ensureCapacity(ByteBuffer buf, int outputLength, boolean allowBufferResize, BufferType bufferType)	Ensure buf is large enough for outputLength.
static boolean	equalsWithShortLength(DataInput in, ByteBuffer toMatch)	Returns true if the buffer at the current position in the input matches given buffer.
static byte[]	getArray(ByteBuffer buffer)	You should almost never use this.
static byte[]	getArray(ByteBuffer buffer, int position, int length)	You should almost never use this.
static float	getFloat(ByteBuffer bytes, int offset)
static int	getShortLength(ByteBuffer bb, int position)
static int	getUnsignedShort(ByteBuffer bb, int position)
static ByteBuffer	hexToBytes(String str)
static InputStream	inputStream(ByteBuffer bytes)
static boolean	isPrefix(ByteBuffer prefix, ByteBuffer value)
static int	lastIndexOf(ByteBuffer buffer, byte valueToFind, int startIndex)	ByteBuffer adaptation of org.apache.commons.lang3.ArrayUtils.lastIndexOf method
static ByteBuffer	minimalBufferFor(ByteBuffer buf)	trims size of bytebuffer to exactly number of bytes in it, to do not hold too much memory
static ByteBuffer[]	minimizeBuffers(ByteBuffer[] src)
static ByteBuffer	objectToBytes(Object obj)
static int	put(ByteBuffer src, ByteBuffer trg)
static ByteBuffer	read(DataInput in, int length)
static byte[]	readBytes(DataInput in, int length)
static ByteBuffer	readBytes(ByteBuffer bb, int length)
static byte[]	readBytesWithLength(DataInput in)
static ByteBuffer	readBytesWithShortLength(ByteBuffer bb)
static void	readFully(FileChannel channel, ByteBuffer dst, long position)
static int	readShortLength(DataInput in)
static int	readShortLength(ByteBuffer bb)
static ByteBuffer	readWithLength(DataInput in)
static ByteBuffer	readWithShortLength(DataInput in)
static ByteBuffer	readWithVIntLength(DataInputPlus in)
static int	serializedSizeWithLength(ByteBuffer buffer)
static int	serializedSizeWithShortLength(ByteBuffer buffer)
static int	serializedSizeWithVIntLength(ByteBuffer buffer)
static void	skipShortLength(DataInputPlus in)
static void	skipWithVIntLength(DataInputPlus in)
static boolean	startsWith(ByteBuffer src, ByteBuffer prefix)
static String	string(ByteBuffer buffer)	Decode a String representation.
static String	string(ByteBuffer buffer, int position, int length)	Decode a String representation.
static String	string(ByteBuffer buffer, int position, int length, Charset charset)	Decode a String representation.
static String	string(ByteBuffer buffer, Charset charset)	Decode a String representation.
static byte	toByte(ByteBuffer bytes)	Convert a byte buffer to a short.
static double	toDouble(ByteBuffer bytes)
static float	toFloat(ByteBuffer bytes)
static int	toInt(ByteBuffer bytes)	Convert a byte buffer to an integer.
static long	toLong(ByteBuffer bytes)
static short	toShort(ByteBuffer bytes)	Convert a byte buffer to a short.
static void	writeShortLength(ByteBuffer bb, int length)
static void	writeWithLength(ByteBuffer bytes, DataOutputPlus out)
static void	writeWithShortLength(ByteBuffer buffer, DataOutputPlus out)
static void	writeWithVIntLength(ByteBuffer bytes, DataOutputPlus out)
static void	writeZeroes(ByteBuffer dest, int count)

Methods inherited from class java.lang.Object

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

Field Details

EMPTY_BYTE_BUFFER

public static final ByteBuffer EMPTY_BYTE_BUFFER

UNSET_BYTE_BUFFER

public static final ByteBuffer UNSET_BYTE_BUFFER

Represents an unset value in bound variables

EMPTY_ARRAY

public static final ByteBuffer[] EMPTY_ARRAY

Constructor Details

ByteBufferUtil

public ByteBufferUtil()

Method Details

compareUnsigned

@Inline
public static int compareUnsigned(ByteBuffer o1,
 ByteBuffer o2)

compare

@Inline
public static int compare(byte[] o1,
 ByteBuffer o2)

compare

@Inline
public static int compare(ByteBuffer o1,
 byte[] o2)

compare

public static int compare(ByteBuffer o1,
 int s1,
 int l1,
 byte[] o2)

compare

public static int compare(byte[] o1,
 ByteBuffer o2,
 int s2,
 int l2)

string

public static String string(ByteBuffer buffer)
                     throws CharacterCodingException

Decode a String representation. This method assumes that the encoding charset is UTF_8.

Parameters:

buffer - a byte buffer holding the string representation

Returns:

the decoded string

Throws:

CharacterCodingException

string

public static String string(ByteBuffer buffer,
 int position,
 int length)
                     throws CharacterCodingException

Decode a String representation. This method assumes that the encoding charset is UTF_8.

Parameters:

buffer - a byte buffer holding the string representation

position - the starting position in buffer to start decoding from

length - the number of bytes from buffer to use

Returns:

the decoded string

Throws:

CharacterCodingException

string

public static String string(ByteBuffer buffer,
 int position,
 int length,
 Charset charset)
                     throws CharacterCodingException

Decode a String representation.

Parameters:

buffer - a byte buffer holding the string representation

position - the starting position in buffer to start decoding from

length - the number of bytes from buffer to use

charset - the String encoding charset

Returns:

the decoded string

Throws:

CharacterCodingException

string

public static String string(ByteBuffer buffer,
 Charset charset)
                     throws CharacterCodingException

Decode a String representation.

Parameters:

buffer - a byte buffer holding the string representation

charset - the String encoding charset

Returns:

the decoded string

Throws:

CharacterCodingException

getArray

public static byte[] getArray(ByteBuffer buffer)

You should almost never use this. Instead, use the write* methods to avoid copies.

getArray

public static byte[] getArray(ByteBuffer buffer,
 int position,
 int length)

You should almost never use this. Instead, use the write* methods to avoid copies.

lastIndexOf

public static int lastIndexOf(ByteBuffer buffer,
 byte valueToFind,
 int startIndex)

ByteBuffer adaptation of org.apache.commons.lang3.ArrayUtils.lastIndexOf method

Parameters:

buffer - the array to traverse for looking for the object, may be null

valueToFind - the value to find

startIndex - the start index (i.e. BB position) to travers backwards from

Returns:

the last index (i.e. BB position) of the value within the array [between buffer.position() and buffer.limit()]; -1 if not found.

bytes

public static ByteBuffer bytes(String s)

Encode a String in a ByteBuffer using UTF_8.

Parameters:

s - the string to encode

Returns:

the encoded string

bytes

public static ByteBuffer bytes(String s,
 Charset charset)

Encode a String in a ByteBuffer using the provided charset.

Parameters:

s - the string to encode

charset - the String encoding charset to use

Returns:

the encoded string

clone

public static ByteBuffer clone(ByteBuffer buffer)

Returns:

a new copy of the data in @param buffer USUALLY YOU SHOULD USE ByteBuffer.duplicate() INSTEAD, which creates a new Buffer (so you can mutate its position without affecting the original) without copying the underlying array.

copyBytes

public static void copyBytes(ByteBuffer src,
 int srcPos,
 byte[] dst,
 int dstPos,
 int length)

Transfer bytes from a ByteBuffer to byte array.

Parameters:

src - the source ByteBuffer

srcPos - starting position in the source ByteBuffer

dst - the destination byte array

dstPos - starting position in the destination byte array

length - the number of bytes to copy

copyBytes

public static void copyBytes(ByteBuffer src,
 int srcPos,
 ByteBuffer dst,
 int dstPos,
 int length)

Transfer bytes from one ByteBuffer to another. This function acts as System.arrayCopy() but for ByteBuffers, and operates safely on direct memory.

Parameters:

src - the source ByteBuffer

srcPos - starting position in the source ByteBuffer

dst - the destination ByteBuffer

dstPos - starting position in the destination ByteBuffer

length - the number of bytes to copy

put

public static int put(ByteBuffer src,
 ByteBuffer trg)

writeZeroes

public static void writeZeroes(ByteBuffer dest,
 int count)

writeWithLength

public static void writeWithLength(ByteBuffer bytes,
 DataOutputPlus out)
                            throws IOException

Throws:

IOException

writeWithVIntLength

public static void writeWithVIntLength(ByteBuffer bytes,
 DataOutputPlus out)
                                throws IOException

Throws:

IOException

writeWithShortLength

public static void writeWithShortLength(ByteBuffer buffer,
 DataOutputPlus out)
                                 throws IOException

Throws:

IOException

readWithLength

public static ByteBuffer readWithLength(DataInput in)
                                 throws IOException

Throws:

IOException

readWithVIntLength

public static ByteBuffer readWithVIntLength(DataInputPlus in)
                                     throws IOException

Throws:

IOException

serializedSizeWithLength

public static int serializedSizeWithLength(ByteBuffer buffer)

serializedSizeWithVIntLength

public static int serializedSizeWithVIntLength(ByteBuffer buffer)

skipWithVIntLength

public static void skipWithVIntLength(DataInputPlus in)
                               throws IOException

Throws:

IOException

readShortLength

public static int readShortLength(DataInput in)
                           throws IOException

Throws:

IOException

readWithShortLength

public static ByteBuffer readWithShortLength(DataInput in)
                                      throws IOException

Parameters:

in - data input

Returns:

An unsigned short in an integer.

Throws:

IOException - if an I/O error occurs.

serializedSizeWithShortLength

public static int serializedSizeWithShortLength(ByteBuffer buffer)

skipShortLength

public static void skipShortLength(DataInputPlus in)
                            throws IOException

Parameters:

in - data input

Throws:

IOException - if an I/O error occurs.

read

public static ByteBuffer read(DataInput in,
 int length)
                       throws IOException

Throws:

IOException

readBytes

public static byte[] readBytes(DataInput in,
 int length)
                        throws IOException

Throws:

IOException

readBytesWithLength

public static byte[] readBytesWithLength(DataInput in)
                                  throws IOException

Throws:

IOException

toInt

public static int toInt(ByteBuffer bytes)

Convert a byte buffer to an integer. Does not change the byte buffer position.

Parameters:

bytes - byte buffer to convert to integer

Returns:

int representation of the byte buffer

toShort

public static short toShort(ByteBuffer bytes)

Convert a byte buffer to a short. Does not change the byte buffer position.

Parameters:

bytes - byte buffer to convert to short

Returns:

short representation of the byte buffer

toByte

public static byte toByte(ByteBuffer bytes)

Convert a byte buffer to a short. Does not change the byte buffer position.

Parameters:

bytes - byte buffer to convert to byte

Returns:

byte representation of the byte buffer

toLong

public static long toLong(ByteBuffer bytes)

toFloat

public static float toFloat(ByteBuffer bytes)

getFloat

public static float getFloat(ByteBuffer bytes,
 int offset)

toDouble

public static double toDouble(ByteBuffer bytes)

objectToBytes

public static ByteBuffer objectToBytes(Object obj)

bytes

public static ByteBuffer bytes(byte b)

bytes

public static ByteBuffer bytes(short s)

bytes

public static ByteBuffer bytes(int i)

bytes

public static ByteBuffer bytes(long n)

bytes

public static ByteBuffer bytes(float f)

bytes

public static ByteBuffer bytes(double d)

inputStream

public static InputStream inputStream(ByteBuffer bytes)

bytesToHex

public static String bytesToHex(ByteBuffer bytes)

hexToBytes

public static ByteBuffer hexToBytes(String str)

compareSubArrays

public static int compareSubArrays(ByteBuffer bytes1,
 int offset1,
 ByteBuffer bytes2,
 int offset2,
 int length)

Compare two ByteBuffer at specified offsets for length. Compares the non equal bytes as unsigned.

Parameters:

bytes1 - First byte buffer to compare.

offset1 - Position to start the comparison at in the first array.

bytes2 - Second byte buffer to compare.

offset2 - Position to start the comparison at in the second array.

length - How many bytes to compare?

Returns:

-1 if byte1 is less than byte2, 1 if byte2 is less than byte1 or 0 if equal.

bytes

public static ByteBuffer bytes(InetAddress address)

bytes

public static ByteBuffer bytes(UUID uuid)

bytes

public static ByteBuffer bytes(TimeUUID uuid)

isPrefix

public static boolean isPrefix(ByteBuffer prefix,
 ByteBuffer value)

canMinimize

public static boolean canMinimize(ByteBuffer buf)

minimalBufferFor

public static ByteBuffer minimalBufferFor(ByteBuffer buf)

trims size of bytebuffer to exactly number of bytes in it, to do not hold too much memory

minimizeBuffers

public static ByteBuffer[] minimizeBuffers(ByteBuffer[] src)

canMinimize

public static boolean canMinimize(ByteBuffer[] src)

getUnsignedShort

public static int getUnsignedShort(ByteBuffer bb,
 int position)

getShortLength

public static int getShortLength(ByteBuffer bb,
 int position)

readShortLength

public static int readShortLength(ByteBuffer bb)

writeShortLength

public static void writeShortLength(ByteBuffer bb,
 int length)

readBytes

public static ByteBuffer readBytes(ByteBuffer bb,
 int length)

readBytesWithShortLength

public static ByteBuffer readBytesWithShortLength(ByteBuffer bb)

ensureCapacity

public static ByteBuffer ensureCapacity(ByteBuffer buf,
 int outputLength,
 boolean allowBufferResize)

Ensure buf is large enough for outputLength. If not, it is cleaned up and a new buffer is allocated; else; buffer has it's position/limit set appropriately.

Parameters:

buf - buffer to test the size of; may be null, in which case, a new buffer is allocated.

outputLength - the minimum target size of the buffer

allowBufferResize - true if resizing (reallocating) the buffer is allowed

Returns:

buf if it was large enough, else a newly allocated buffer.

ensureCapacity

public static ByteBuffer ensureCapacity(ByteBuffer buf,
 int outputLength,
 boolean allowBufferResize,
 BufferType bufferType)

Ensure buf is large enough for outputLength. If not, it is cleaned up and a new buffer is allocated; else; buffer has it's position/limit set appropriately.

Parameters:

buf - buffer to test the size of; may be null, in which case, a new buffer is allocated.

outputLength - the minimum target size of the buffer

allowBufferResize - true if resizing (reallocating) the buffer is allowed

bufferType - on- or off- heap byte buffer

Returns:

buf if it was large enough, else a newly allocated buffer.

contains

public static boolean contains(ByteBuffer buffer,
 ByteBuffer subBuffer)

Check is the given buffer contains a given sub-buffer.

Parameters:

buffer - The buffer to search for sequence of bytes in.

subBuffer - The buffer to match.

Returns:

true if buffer contains sub-buffer, false otherwise.

startsWith

public static boolean startsWith(ByteBuffer src,
 ByteBuffer prefix)

endsWith

public static boolean endsWith(ByteBuffer src,
 ByteBuffer suffix)

equalsWithShortLength

public static boolean equalsWithShortLength(DataInput in,
 ByteBuffer toMatch)
                                     throws IOException

Returns true if the buffer at the current position in the input matches given buffer. If true, the input is positioned at the end of the consumed buffer. If false, the position of the input is undefined.

The matched buffer is unchanged

Throws:

IOException

readFully

public static void readFully(FileChannel channel,
 ByteBuffer dst,
 long position)
                      throws IOException

Throws:

IOException