Package org.apache.cassandra.utils.vint

Class VIntCoding

java.lang.Object

org.apache.cassandra.utils.vint.VIntCoding

public class VIntCoding
extends java.lang.Object

Borrows idea from https://developers.google.com/protocol-buffers/docs/encoding#varints

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	VIntCoding.VIntOutOfRangeException	Throw when attempting to decode a vint and the output type doesn't have enough space to fit the value that was decoded

Field Summary

Fields

Modifier and Type	Field	Description
protected static io.netty.util.concurrent.FastThreadLocal<byte[]>	encodingBuffer
static int	MAX_SIZE

Constructor Summary

Constructors

Constructor	Description
VIntCoding()

Method Summary

Modifier and Type	Method	Description
static int	checkedCast(long value)
static int	computeUnsignedVIntSize(long value)	Compute the number of bytes that would be needed to encode an unsigned varint.
static int	computeUnsignedVIntSize(java.nio.ByteBuffer input, int readerIndex)	Computes size of an unsigned vint that starts at readerIndex of the provided ByteBuf.
static int	computeUnsignedVIntSize(java.nio.ByteBuffer input, int readerIndex, int readerLimit)
static int	computeVIntSize(long param)	Compute the number of bytes that would be needed to encode a varint.
static long	decodeZigZag64(long n)	Decode a ZigZag-encoded 64-bit value.
static int	encodeExtraBytesToRead(int extraBytesToRead)
static long	encodeZigZag64(long n)	Encode a ZigZag-encoded 64-bit value.
static int	firstByteValueMask(int extraBytesToRead)
static long	getUnsignedVInt(java.nio.ByteBuffer input, int readerIndex)
static long	getUnsignedVInt(java.nio.ByteBuffer input, int readerIndex, int readerLimit)
static <V> long	getUnsignedVInt(V input, ValueAccessor<V> accessor, int readerIndex)
static <V> long	getUnsignedVInt(V input, ValueAccessor<V> accessor, int readerIndex, int readerLimit)
static int	getUnsignedVInt32(java.nio.ByteBuffer input, int readerIndex)	Read up to a 32-bit integer back, using the unsigned (no zigzag) encoding.
static <V> int	getUnsignedVInt32(V input, ValueAccessor<V> accessor, int readerIndex)
static long	getVInt(java.nio.ByteBuffer input, int readerIndex)
static <V> long	getVInt(V input, ValueAccessor<V> accessor, int readerIndex)
static int	getVInt32(java.nio.ByteBuffer input, int readerIndex)
static <V> int	getVInt32(V input, ValueAccessor<V> accessor, int readerIndex)
static int	numberOfExtraBytesToRead(int firstByte)
static long	readUnsignedVInt(java.io.DataInput input)
static int	readUnsignedVInt32(java.io.DataInput input)	Read up to a 32-bit integer.
static long	readVInt(java.io.DataInput input)
static int	readVInt32(java.io.DataInput input)	Read up to a signed 32-bit integer back.
static void	skipUnsignedVInt(DataInputPlus input)
static void	writeUnsignedVInt(int value, java.nio.ByteBuffer output)	Deprecated. See CASSANDRA-18099
static void	writeUnsignedVInt(int value, DataOutputPlus output)	Deprecated. See CASSANDRA-18099
static void	writeUnsignedVInt(long value, java.nio.ByteBuffer output)
static void	writeUnsignedVInt(long value, DataOutputPlus output)
static <V> int	writeUnsignedVInt(long value, V output, int offset, ValueAccessor<V> accessor)
static void	writeUnsignedVInt32(int value, java.nio.ByteBuffer output)
static void	writeUnsignedVInt32(int value, DataOutputPlus output)
static <V> int	writeUnsignedVInt32(int value, V output, int offset, ValueAccessor<V> accessor)
static void	writeVInt(int value, java.nio.ByteBuffer output)	Deprecated. See CASSANDRA-18099
static void	writeVInt(int value, DataOutputPlus output)	Deprecated. See CASSANDRA-18099
static void	writeVInt(long value, java.nio.ByteBuffer output)
static void	writeVInt(long value, DataOutputPlus output)
static <V> int	writeVInt(long value, V output, int offset, ValueAccessor<V> accessor)
static void	writeVInt32(int value, java.nio.ByteBuffer output)
static void	writeVInt32(int value, DataOutputPlus output)
static <V> int	writeVInt32(int value, V output, int offset, ValueAccessor<V> accessor)

Methods inherited from class java.lang.Object

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

Field Detail

encodingBuffer

protected static final io.netty.util.concurrent.FastThreadLocal<byte[]> encodingBuffer

MAX_SIZE

public static final int MAX_SIZE

See Also:

Constant Field Values

Constructor Detail

VIntCoding

public VIntCoding()

Method Detail

readUnsignedVInt

public static long readUnsignedVInt(java.io.DataInput input)
                             throws java.io.IOException

Throws:

java.io.IOException

skipUnsignedVInt

public static void skipUnsignedVInt(DataInputPlus input)
                             throws java.io.IOException

Throws:

java.io.IOException

getUnsignedVInt32

public static int getUnsignedVInt32(java.nio.ByteBuffer input,
                                    int readerIndex)

Read up to a 32-bit integer back, using the unsigned (no zigzag) encoding. Note this method is the same as readUnsignedVInt(DataInput), except that we do *not* block if there are not enough bytes in the buffer to reconstruct the value.

Throws:

VIntCoding.VIntOutOfRangeException - If the vint doesn't fit into a 32-bit integer

getVInt32

public static int getVInt32(java.nio.ByteBuffer input,
                            int readerIndex)

getVInt

public static long getVInt(java.nio.ByteBuffer input,
                           int readerIndex)

getUnsignedVInt

public static long getUnsignedVInt(java.nio.ByteBuffer input,
                                   int readerIndex)

getUnsignedVInt

public static long getUnsignedVInt(java.nio.ByteBuffer input,
                                   int readerIndex,
                                   int readerLimit)

getUnsignedVInt32

public static <V> int getUnsignedVInt32(V input,
                                        ValueAccessor<V> accessor,
                                        int readerIndex)

getVInt32

public static <V> int getVInt32(V input,
                                ValueAccessor<V> accessor,
                                int readerIndex)

getVInt

public static <V> long getVInt(V input,
                               ValueAccessor<V> accessor,
                               int readerIndex)

getUnsignedVInt

public static <V> long getUnsignedVInt(V input,
                                       ValueAccessor<V> accessor,
                                       int readerIndex)

getUnsignedVInt

public static <V> long getUnsignedVInt(V input,
                                       ValueAccessor<V> accessor,
                                       int readerIndex,
                                       int readerLimit)

computeUnsignedVIntSize

public static int computeUnsignedVIntSize(java.nio.ByteBuffer input,
                                          int readerIndex)

Computes size of an unsigned vint that starts at readerIndex of the provided ByteBuf.

Returns:

-1 if there are not enough bytes in the input to calculate the size; else, the vint unsigned value size in bytes.

computeUnsignedVIntSize

public static int computeUnsignedVIntSize(java.nio.ByteBuffer input,
                                          int readerIndex,
                                          int readerLimit)

readVInt

public static long readVInt(java.io.DataInput input)
                     throws java.io.IOException

Throws:

java.io.IOException

readVInt32

public static int readVInt32(java.io.DataInput input)
                      throws java.io.IOException

Read up to a signed 32-bit integer back. Assumes the vint was written using writeVInt32(int, DataOutputPlus) or similar that zigzag encodes the integer.

Throws:

VIntCoding.VIntOutOfRangeException - If the vint doesn't fit into a 32-bit integer

java.io.IOException

readUnsignedVInt32

public static int readUnsignedVInt32(java.io.DataInput input)
                              throws java.io.IOException

Read up to a 32-bit integer. This method assumes the original integer was written using writeUnsignedVInt32(int, DataOutputPlus) or similar that doesn't zigzag encodes the vint.

Throws:

VIntCoding.VIntOutOfRangeException - If the vint doesn't fit into a 32-bit integer

java.io.IOException

firstByteValueMask

public static int firstByteValueMask(int extraBytesToRead)

encodeExtraBytesToRead

public static int encodeExtraBytesToRead(int extraBytesToRead)

numberOfExtraBytesToRead

public static int numberOfExtraBytesToRead(int firstByte)

writeUnsignedVInt

@Deprecated(since="5.0")
public static void writeUnsignedVInt(int value,
                                     DataOutputPlus output)
                              throws java.io.IOException

Deprecated.

See CASSANDRA-18099

Throws:

java.io.IOException

writeUnsignedVInt

@Inline
public static void writeUnsignedVInt(long value,
                                     DataOutputPlus output)
                              throws java.io.IOException

Throws:

java.io.IOException

writeUnsignedVInt32

public static void writeUnsignedVInt32(int value,
                                       DataOutputPlus output)
                                throws java.io.IOException

Throws:

java.io.IOException

writeUnsignedVInt

@Deprecated(since="5.0")
public static void writeUnsignedVInt(int value,
                                     java.nio.ByteBuffer output)
                              throws java.io.IOException

Deprecated.

See CASSANDRA-18099

Throws:

java.io.IOException

writeUnsignedVInt

@Inline
public static void writeUnsignedVInt(long value,
                                     java.nio.ByteBuffer output)

writeVInt

@Inline
public static <V> int writeVInt(long value,
                                V output,
                                int offset,
                                ValueAccessor<V> accessor)

writeVInt32

@Inline
public static <V> int writeVInt32(int value,
                                  V output,
                                  int offset,
                                  ValueAccessor<V> accessor)

writeUnsignedVInt32

@Inline
public static <V> int writeUnsignedVInt32(int value,
                                          V output,
                                          int offset,
                                          ValueAccessor<V> accessor)

writeUnsignedVInt

@Inline
public static <V> int writeUnsignedVInt(long value,
                                        V output,
                                        int offset,
                                        ValueAccessor<V> accessor)

writeUnsignedVInt32

@Inline
public static void writeUnsignedVInt32(int value,
                                       java.nio.ByteBuffer output)

writeVInt

@Deprecated(since="5.0")
public static void writeVInt(int value,
                             DataOutputPlus output)
                      throws java.io.IOException

Deprecated.

See CASSANDRA-18099

Throws:

java.io.IOException

writeVInt

@Inline
public static void writeVInt(long value,
                             DataOutputPlus output)
                      throws java.io.IOException

Throws:

java.io.IOException

writeVInt32

@Inline
public static void writeVInt32(int value,
                               DataOutputPlus output)
                        throws java.io.IOException

Throws:

java.io.IOException

writeVInt

@Deprecated(since="5.0")
public static void writeVInt(int value,
                             java.nio.ByteBuffer output)

Deprecated.

See CASSANDRA-18099

writeVInt

@Inline
public static void writeVInt(long value,
                             java.nio.ByteBuffer output)

writeVInt32

@Inline
public static void writeVInt32(int value,
                               java.nio.ByteBuffer output)

decodeZigZag64

public static long decodeZigZag64(long n)

Decode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers into values that can be efficiently encoded with varint. (Otherwise, negative values must be sign-extended to 64 bits to be varint encoded, thus always taking 10 bytes on the wire.)

Parameters:

n - An unsigned 64-bit integer, stored in a signed int because Java has no explicit unsigned support.

Returns:

A signed 64-bit integer.

encodeZigZag64

public static long encodeZigZag64(long n)

Encode a ZigZag-encoded 64-bit value. ZigZag encodes signed integers into values that can be efficiently encoded with varint. (Otherwise, negative values must be sign-extended to 64 bits to be varint encoded, thus always taking 10 bytes on the wire.)

Parameters:

n - A signed 64-bit integer.

Returns:

An unsigned 64-bit integer, stored in a signed int because Java has no explicit unsigned support.

computeVIntSize

public static int computeVIntSize(long param)

Compute the number of bytes that would be needed to encode a varint.

computeUnsignedVIntSize

public static int computeUnsignedVIntSize(long value)

Compute the number of bytes that would be needed to encode an unsigned varint.

checkedCast

public static int checkedCast(long value)