tachyon.util.io

Class BufferUtils

java.lang.Object

tachyon.util.io.BufferUtils

public final class BufferUtils
extends Object

Utilities related to buffers, not only ByteBuffer.

Method Summary

Methods

Modifier and Type	Method and Description
static int	byteToInt(byte b)
static void	cleanDirectBuffer(ByteBuffer buffer) Forces to unmap a direct buffer if this buffer is no longer used.
static ByteBuffer	cloneByteBuffer(ByteBuffer buf) Clones a bytebuffer.
static List<ByteBuffer>	cloneByteBufferList(List<ByteBuffer> source) Clones a list of ByteBuffers.
static boolean	equalIncreasingByteArray(int len, byte[] arr) Checks if the given byte array starts with an increasing sequence of bytes starting at zero of length equal to or greater than the given length.
static boolean	equalIncreasingByteArray(int start, int len, byte[] arr) Checks if the given byte array starts with an increasing sequence of bytes starting at the given value of length equal to or greater than the given length.
static boolean	equalIncreasingByteBuffer(int start, int len, ByteBuffer buf) Checks if the given ByteBuffer starts with an increasing sequence of bytes starting at the given value of length equal to or greater than the given length.
static void	fastCopy(ReadableByteChannel src, WritableByteChannel dest) An efficient copy between two channels with a fixed-size buffer.
static ByteBuffer	generateNewByteBufferFromThriftRPCResults(ByteBuffer data) Extracts a correct ByteBuffer from Thrift RPC result.
static byte[]	getIncreasingByteArray(int len) Gets an increasing sequence of bytes starting at zero.
static byte[]	getIncreasingByteArray(int start, int len) Gets an increasing sequence of bytes starting with the given value.
static ByteBuffer	getIncreasingByteBuffer(int len) Gets a ByteBuffer containing an increasing sequence of bytes starting at zero.
static ByteBuffer	getIncreasingByteBuffer(int start, int len) Gets a ByteBuffer containing an increasing sequence of bytes starting at the given value.
static ByteBuffer	getIncreasingIntBuffer(int len) Gets a ByteBuffer containing an increasing sequence of integers starting at zero.
static ByteBuffer	getIncreasingIntBuffer(int start, int len) Get a ByteBuffer containing an increasing sequence of integers starting at the given value.
static void	putIntByteBuffer(ByteBuffer buf, int b) Puts a byte (the first byte of an integer) into a ByteBuffer.
static void	writeBufferToFile(String path, byte[] buffer) Writes buffer to the given file path.

Methods inherited from class java.lang.Object

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

Method Detail

byteToInt

public static int byteToInt(byte b)

cleanDirectBuffer

public static void cleanDirectBuffer(ByteBuffer buffer)

Forces to unmap a direct buffer if this buffer is no longer used. After calling this method, this direct buffer should be discarded. This is unsafe operation and currently a walk-around to avoid huge memory occupation caused by memory map.

NOTE: DirectByteBuffers are not guaranteed to be garbage-collected immediately after their references are released and may lead to OutOfMemoryError. This function helps by calling the Cleaner method of a DirectByteBuffer explicitly. See more discussion.

Parameters:

buffer - the byte buffer to be unmapped, this must be a direct buffer

cloneByteBuffer

public static ByteBuffer cloneByteBuffer(ByteBuffer buf)

Clones a bytebuffer.

The new bytebuffer will have the same content, but the type of the bytebuffer may not be the same.

Parameters:

buf - The ByteBuffer to clone

Returns:

The new ByteBuffer

cloneByteBufferList

public static List<ByteBuffer> cloneByteBufferList(List<ByteBuffer> source)

Clones a list of ByteBuffers.

Parameters:

source - the list of ByteBuffers to clone

Returns:

the new list of ByteBuffers

generateNewByteBufferFromThriftRPCResults

public static ByteBuffer generateNewByteBufferFromThriftRPCResults(ByteBuffer data)

Extracts a correct ByteBuffer from Thrift RPC result.

Parameters:

data - result of Thrift RPC

Returns:

ByteBuffer with data extracted from the Thrift RPC result

putIntByteBuffer

public static void putIntByteBuffer(ByteBuffer buf,
                    int b)

Puts a byte (the first byte of an integer) into a ByteBuffer.

Parameters:

buf - ByteBuffer to use

b - byte to put into the ByteBuffer

getIncreasingByteArray

public static byte[] getIncreasingByteArray(int len)

Gets an increasing sequence of bytes starting at zero.

Parameters:

len - the target length of the sequence

Returns:

an increasing sequence of bytes

getIncreasingByteArray

public static byte[] getIncreasingByteArray(int start,
                            int len)

Gets an increasing sequence of bytes starting with the given value.

Parameters:

start - the starting value to use

len - the target length of the sequence

Returns:

an increasing sequence of bytes

equalIncreasingByteArray

public static boolean equalIncreasingByteArray(int len,
                               byte[] arr)

Checks if the given byte array starts with an increasing sequence of bytes starting at zero of length equal to or greater than the given length.

Parameters:

len - the target length of the sequence

arr - the byte array to check

Returns:

true if the byte array has a prefix of length len that is an increasing sequence of bytes starting at zero

equalIncreasingByteArray

public static boolean equalIncreasingByteArray(int start,
                               int len,
                               byte[] arr)

Checks if the given byte array starts with an increasing sequence of bytes starting at the given value of length equal to or greater than the given length.

Parameters:

start - the starting value to use

len - the target length of the sequence

arr - the byte array to check

Returns:

true if the byte array has a prefix of length len that is an increasing sequence of bytes starting at start

getIncreasingByteBuffer

public static ByteBuffer getIncreasingByteBuffer(int len)

Gets a ByteBuffer containing an increasing sequence of bytes starting at zero.

Parameters:

len - the target length of the sequence

Returns:

ByteBuffer containing an increasing sequence of bytes

getIncreasingByteBuffer

public static ByteBuffer getIncreasingByteBuffer(int start,
                                 int len)

Gets a ByteBuffer containing an increasing sequence of bytes starting at the given value.

Parameters:

len - the target length of the sequence

start - the starting value to use

Returns:

ByteBuffer containing an increasing sequence of bytes

equalIncreasingByteBuffer

public static boolean equalIncreasingByteBuffer(int start,
                                int len,
                                ByteBuffer buf)

Checks if the given ByteBuffer starts with an increasing sequence of bytes starting at the given value of length equal to or greater than the given length.

Parameters:

start - the starting value to use

len - the target length of the sequence

buf - the ByteBuffer to check

Returns:

true if the ByteBuffer has a prefix of length len that is an increasing sequence of bytes starting at start

getIncreasingIntBuffer

public static ByteBuffer getIncreasingIntBuffer(int len)

Gets a ByteBuffer containing an increasing sequence of integers starting at zero.

Parameters:

len - the target length of the sequence

Returns:

ByteBuffer containing an increasing sequence of integers

getIncreasingIntBuffer

public static ByteBuffer getIncreasingIntBuffer(int start,
                                int len)

Get a ByteBuffer containing an increasing sequence of integers starting at the given value.

Parameters:

start - the starting value to use

len - the target length of the sequence

Returns:

ByteBuffer containing an increasing sequence of integers

writeBufferToFile

public static void writeBufferToFile(String path,
                     byte[] buffer)
                              throws IOException

Writes buffer to the given file path.

Parameters:

path - file path to write the data

buffer - raw data

Throws:

IOException - if the operation fails

fastCopy

public static void fastCopy(ReadableByteChannel src,
            WritableByteChannel dest)
                     throws IOException

An efficient copy between two channels with a fixed-size buffer.

Parameters:

src - the source channel

dest - the destination channel

Throws:

IOException - if the copy fails