uk.ac.starlink.oldfits

Class MultiMappedFile

java.lang.Object

uk.ac.starlink.oldfits.AbstractArrayDataIO

uk.ac.starlink.oldfits.MultiMappedFile

All Implemented Interfaces:

DataInput, DataOutput, ArrayDataInput, ArrayDataOutput, RandomAccess

public class MultiMappedFile
extends AbstractArrayDataIO
implements RandomAccess

ArrayDataIO implementation which works by mapping but is capable of splitting a file up into multiple mapped sections. This will be necessary if it's larger than Integer.MAX_VALUE bytes, though note that doing this is only going to be a good idea on a 64-bit OS.

Since:

9 Jan 2007

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
MultiMappedFile(FileChannel chan, FileChannel.MapMode mode, int blockBytes) Constructs a MultiMappedFile from a channel.
MultiMappedFile(File file, FileChannel.MapMode mode, int blockBytes) Constructs a MultiMappedFile from a file.

Method Summary

Modifier and Type	Method and Description
void	close()
void	flush()
protected byte	get() Reads one byte from the current position.
protected void	get(byte[] buf, int offset, int length) Reads bytes into a buffer from the current position.
long	getFilePointer() Get the current position in the stream
long	length() Returns the size of this buffer.
void	mark(int readlimit)
boolean	markSupported()
protected void	put(byte b) Writes a single byte at the current position.
protected void	put(byte[] buf, int offset, int length) Writes bytes from a buffer to the current position.
protected long	remaining() Returns the number of bytes remaining between the current position and the end of the file.
void	reset()
void	seek(long offsetFromStart) Move to a specified location in the stream.
long	skip(long nskip)
void	skipAllBytes(int toSkip)
void	skipAllBytes(long nskip)
int	skipBytes(int toSkip)

Methods inherited from class uk.ac.starlink.oldfits.AbstractArrayDataIO

read, read, read, read, read, read, read, read, read, read, read, read, read, read, read, read, readArray, readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLArray, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, write, writeArray, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods inherited from class java.lang.Object

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

Methods inherited from interface nom.tam.util.ArrayDataInput

read, read, read, read, read, read, read, read, read, read, read, read, read, read, read, read, readArray

Methods inherited from interface java.io.DataInput

readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF

Constructor Detail

MultiMappedFile

public MultiMappedFile(FileChannel chan,
                       FileChannel.MapMode mode,
                       int blockBytes)
                throws IOException

Constructs a MultiMappedFile from a channel.

Parameters:

chan - file channel

mode - mapping mode

blockBytes - number of bytes per mapped block (though the final one may have fewer)

Throws:

IOException

MultiMappedFile

public MultiMappedFile(File file,
                       FileChannel.MapMode mode,
                       int blockBytes)
                throws IOException

Constructs a MultiMappedFile from a file.

Parameters:

file - file

mode - mapping mode

blockBytes - number of bytes per mapped block (though the final one may have fewer)

Throws:

IOException

Method Detail

seek

public void seek(long offsetFromStart)
          throws IOException

Description copied from interface: RandomAccess

Move to a specified location in the stream.

Specified by:

seek in interface RandomAccess

Throws:

IOException

skip

public long skip(long nskip)
          throws IOException

Specified by:

skip in interface ArrayDataInput

Throws:

IOException

skipAllBytes

public void skipAllBytes(long nskip)
                  throws IOException

Throws:

IOException

skipAllBytes

public void skipAllBytes(int toSkip)
                  throws IOException

Throws:

IOException

getFilePointer

public long getFilePointer()

Description copied from interface: RandomAccess

Get the current position in the stream

Specified by:

getFilePointer in interface RandomAccess

skipBytes

public int skipBytes(int toSkip)
              throws IOException

Specified by:

skipBytes in interface DataInput

Throws:

IOException

markSupported

public boolean markSupported()

mark

public void mark(int readlimit)

reset

public void reset()
           throws IOException

Throws:

IOException

get

protected byte get()
            throws IOException

Description copied from class: AbstractArrayDataIO

Reads one byte from the current position.

Specified by:

get in class AbstractArrayDataIO

Returns:

next byte

Throws:

IOException

get

protected void get(byte[] buf,
                   int offset,
                   int length)
            throws IOException

Description copied from class: AbstractArrayDataIO

Reads bytes into a buffer from the current position.

Specified by:

get in class AbstractArrayDataIO

Parameters:

buf - destination buffer

offset - offset of first byte in buf to be written

length - maximum number of bytes to be written to buf

Throws:

IOException

put

protected void put(byte b)
            throws IOException

Description copied from class: AbstractArrayDataIO

Writes a single byte at the current position.

Specified by:

put in class AbstractArrayDataIO

Parameters:

b - output byte

Throws:

IOException

put

protected void put(byte[] buf,
                   int offset,
                   int length)
            throws IOException

Description copied from class: AbstractArrayDataIO

Writes bytes from a buffer to the current position.

Specified by:

put in class AbstractArrayDataIO

Parameters:

buf - source buffer

offset - offset of first byte in buf to be read

length - number of bytes from buf to be read

Throws:

IOException

length

public long length()

Description copied from class: AbstractArrayDataIO

Returns the size of this buffer. May be -1 if not known/unlimited.

Specified by:

length in class AbstractArrayDataIO

Returns:

length or -1

remaining

protected long remaining()

Description copied from class: AbstractArrayDataIO

Returns the number of bytes remaining between the current position and the end of the file. If there is no end to the file, it is permissible to return Long.MAX_VALUE;

Specified by:

remaining in class AbstractArrayDataIO

Returns:

number of bytes left in file

close

public void close()
           throws IOException

Specified by:

close in interface ArrayDataInput

Specified by:

close in interface ArrayDataOutput

Throws:

IOException

flush

public void flush()

Specified by:

flush in interface ArrayDataOutput