CADI.Common.io
Class BufferedDataIOStream

java.lang.Object
  CADI.Common.io.BufferedDataIOStream

All Implemented Interfaces:

java.io.DataInput, java.io.DataOutput

public class BufferedDataIOStream
extends java.lang.Object
implements java.io.DataInput, java.io.DataOutput

Version:

beta 0.1 2007/12/22

Author:

Group on Interactive Coding of Images (GICI)

Field Summary

private byte[]	buf An array of bytes used to buffer the input/output data.
private int	count The index one greater than the last valid byte in the buffer.
private static int	DEFAULT_BUFFER_SIZE It is the default size for the buffer when this was not passed
private boolean	EOFInBuffer Indicates, when data source is a file, if the End Of File mark is reached.
private java.io.RandomAccessFile	file
private long	filePos Indicates the offset of the file where data are from.
(package private) boolean	isChangedBuf Indicates if the buf has been changed since the last time it was written in the file.
(package private) boolean	isResizeAllowed Indicates if the buffer size can be resized.
private int	mode It is the buffer access.
private static int	MODE_R
private static int	MODE_RW
private static int	MODE_RWU
private int	offset Indicates the first available data in the buffer.
private int	pos The index of the next byte to read/write from/to the buffer.
private boolean	useFile Indicates the data source, whether data is readed from file or no.

Constructor Summary

BufferedDataIOStream(java.io.File file, java.lang.String mode)

BufferedDataIOStream(int sz, java.lang.String mode)
Constructor.

BufferedDataIOStream(java.io.RandomAccessFile file)

BufferedDataIOStream(java.lang.String name, java.lang.String mode)

Method Summary

long	available() Returns the number of bytes that can be read from this buffer without blocking.
void	close()
void	flush() Data stored in the buff must be written in a file.
int	getCapacity()
long	getPos()
long	length() Returns the number of bytes that can be read from this buffer, taking into account any buffering.
int	read() Reads the next byte of data from the input stream.
private int	read1() Reads the next byte of data from this input stream.
boolean	readBoolean()
private void	readBuffer()
byte	readByte() See the general contract of the readByte method of DataInput.
char	readChar()
double	readDouble() See the general contract of the readDouble method of DataInput.
float	readFloat() See the general contract of the readFloat method of DataInput.
void	readFully(byte[] b) See the general contract of the readFully method of DataInput.
void	readFully(byte[] b, int off, int len) See the general contract of the readFully method of DataInput.
int	readInt()
java.lang.String	readLine()
long	readLong()
short	readShort() Reads two input bytes and returns a short value.
int	readUnsignedByte() Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
int	readUnsignedShort()
java.lang.String	readUTF()
private void	resizeBuffer(int newSize)
void	seek(long pos)
private void	setMode(java.lang.String mode)
void	setResizable(boolean isResizeAllowed) Sets if buffer can be resized or not.
int	skipBytes(int n)
long	skipBytes(long n)
java.lang.String	toString() For debugging purpose.
void	write(byte[] b) Writes to the output stream all the bytes in array b.
void	write(byte[] b, int off, int len) Writes len bytes from array b, in order, to the output stream.
void	write(int b) Writes to the output stream the eight low-order bits of the argument b.
void	writeBoolean(boolean v) Writes a boolean to the underlying output stream as a 1-byte value.
void	writeByte(int v)
void	writeBytes(java.lang.String s)
void	writeChar(int v)
void	writeChars(java.lang.String s)
void	writeDouble(double v)
void	writeFloat(float v)
void	writeInt(int v)
void	writeLong(long v)
void	writeShort(int v)
void	writeUTF(java.lang.String s)

Methods inherited from class java.lang.Object

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

Field Detail

buf

private volatile byte[] buf

An array of bytes used to buffer the input/output data. Elements buf[0] through buf[count-1] are the only bytes that can ever be read/write from/to the buffer; element buf[pos] is the next byte to be read/write.

pos

private int pos

The index of the next byte to read/write from/to the buffer. This value should always be nonnegative and not shorter than offset and not larger than the value of count. The next byte to be read/write from/to the buffer will be buf[pos].

count

private int count

The index one greater than the last valid byte in the buffer. This value should always be nonnegative and not larger than the length of buf. It is one greater than the position of the last byte within buf that can ever be read/write from/to the buffer.

offset

private int offset

Indicates the first available data in the buffer.

file

private java.io.RandomAccessFile file

filePos

private long filePos

Indicates the offset of the file where data are from.

EOFInBuffer

private boolean EOFInBuffer

Indicates, when data source is a file, if the End Of File mark is reached. Then, the buf contains the last bytes of the file.

mode

private int mode

It is the buffer access. Allowed values are: "r" read "rw" read & write (if file/buffer exists, removes it before) "rw+" read & write (if file/buffer exists, updates it)

MODE_R

private static int MODE_R

MODE_RW

private static int MODE_RW

MODE_RWU

private static int MODE_RWU

useFile

private boolean useFile

Indicates the data source, whether data is readed from file or no.

isChangedBuf

boolean isChangedBuf

Indicates if the buf has been changed since the last time it was written in the file.

isResizeAllowed

boolean isResizeAllowed

Indicates if the buffer size can be resized. This attribute will only be taken into account whe data are stored in the buffer, i.e., writeToFile is false.

DEFAULT_BUFFER_SIZE

private static int DEFAULT_BUFFER_SIZE

It is the default size for the buffer when this was not passed

Constructor Detail

BufferedDataIOStream

public BufferedDataIOStream(int sz,
                            java.lang.String mode)

Constructor.

Parameters:

sz - buffer size

BufferedDataIOStream

public BufferedDataIOStream(java.lang.String name,
                            java.lang.String mode)
                     throws java.io.FileNotFoundException

Parameters:

name -

Throws:

java.io.FileNotFoundException

BufferedDataIOStream

public BufferedDataIOStream(java.io.File file,
                            java.lang.String mode)
                     throws java.io.FileNotFoundException

Parameters:

file -

Throws:

java.io.FileNotFoundException

BufferedDataIOStream

public BufferedDataIOStream(java.io.RandomAccessFile file)
                     throws java.io.FileNotFoundException

Parameters:

file -

Throws:

java.io.FileNotFoundException

Method Detail

setResizable

public void setResizable(boolean isResizeAllowed)

Sets if buffer can be resized or not.

Parameters:

isResizeAllowed -

write

public void write(int b)
           throws java.io.IOException

Writes to the output stream the eight low-order bits of the argument b. The 24 high-order bits of b are ignored.

Specified by:

write in interface java.io.DataOutput

Parameters:

b - the byte to be written.

Throws:

java.io.IOException - if an I/O error occurs.

read

public int read()
         throws java.io.EOFException,
                java.io.IOException

Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

A subclass must provide an implementation of this method.

Returns:

the next byte of data, or -1 if the end of the stream is reached.

Throws:

java.io.IOException

java.io.EOFException

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b)
           throws java.io.IOException

Writes to the output stream all the bytes in array b. If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are written. Otherwise, the byte b[0] is written first, then b[1], and so on; the last byte written is b[b.length-1].

Specified by:

write in interface java.io.DataOutput

Parameters:

b - the data.

Throws:

java.io.IOException - if an I/O error occurs.

readFully

public void readFully(byte[] b)
               throws java.io.IOException

See the general contract of the readFully method of DataInput.

Bytes for this operation are read from the contained input stream.

Specified by:

readFully in interface java.io.DataInput

Parameters:

b - the buffer into which the data is read.

Throws:

java.io.EOFException - if this input stream reaches the end before reading all the bytes.

java.io.IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException

Writes len bytes from array b, in order, to the output stream. If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are written. Otherwise, the byte b[off] is written first, then b[off+1], and so on; the last byte written is b[off+len-1].

Specified by:

write in interface java.io.DataOutput

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

java.io.IOException - if an I/O error occurs.

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws java.io.EOFException,
                      java.io.IOException

See the general contract of the readFully method of DataInput.

Bytes for this operation are read from the contained input stream.

Specified by:

readFully in interface java.io.DataInput

Parameters:

b - the buffer into which the data is read.

off - the start offset of the data.

len - the number of bytes to read.

Throws:

java.io.EOFException

java.io.EOFException - if this input stream reaches the end before reading all the bytes.

java.io.IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

skipBytes

public int skipBytes(int n)
              throws java.io.IOException

Specified by:

skipBytes in interface java.io.DataInput

Throws:

java.io.IOException

writeBoolean

public void writeBoolean(boolean v)
                  throws java.io.IOException

Writes a boolean to the underlying output stream as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0. If no exception is thrown, the counter written is incremented by 1.

Specified by:

writeBoolean in interface java.io.DataOutput

Parameters:

v - a boolean value to be written.

Throws:

java.io.IOException - if an I/O error occurs.

See Also:

FilterOutputStream.out

readBoolean

public boolean readBoolean()
                    throws java.io.IOException

Specified by:

readBoolean in interface java.io.DataInput

Throws:

java.io.IOException

writeByte

public void writeByte(int v)
               throws java.io.IOException

Specified by:

writeByte in interface java.io.DataOutput

Throws:

java.io.IOException

readByte

public byte readByte()
              throws java.io.EOFException,
                     java.io.IOException

See the general contract of the readByte method of DataInput.

Bytes for this operation are read from the contained stream.

Specified by:

readByte in interface java.io.DataInput

Returns:

the next byte of this input stream as a signed 8-bit byte.

Throws:

java.io.IOException

java.io.IOException - if an I/O error occurs.

java.io.EOFException

readUnsignedByte

public int readUnsignedByte()
                     throws java.io.EOFException,
                            java.io.IOException

Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.

Specified by:

readUnsignedByte in interface java.io.DataInput

Returns:

the unsigned 8-bit value read.

Throws:

java.io.EOFException - if this stream reaches the end before reading all the bytes.

java.io.IOException - if an I/O error occurs.

writeShort

public void writeShort(int v)
                throws java.io.IOException

Specified by:

writeShort in interface java.io.DataOutput

Throws:

java.io.IOException

readShort

public short readShort()
                throws java.io.EOFException,
                       java.io.IOException

Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte. The value returned is:

(short)((a << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput.

Specified by:

readShort in interface java.io.DataInput

Returns:

the 16-bit value read.

Throws:

java.io.EOFException - if this stream reaches the end before reading all the bytes.

java.io.IOException - if an I/O error occurs.

readUnsignedShort

public int readUnsignedShort()
                      throws java.io.EOFException,
                             java.io.IOException

Specified by:

readUnsignedShort in interface java.io.DataInput

Throws:

java.io.EOFException

java.io.IOException

writeChar

public void writeChar(int v)
               throws java.io.IOException

Specified by:

writeChar in interface java.io.DataOutput

Throws:

java.io.IOException

readChar

public char readChar()
              throws java.io.EOFException,
                     java.io.IOException

Specified by:

readChar in interface java.io.DataInput

Throws:

java.io.EOFException

java.io.IOException

writeInt

public void writeInt(int v)
              throws java.io.IOException

Specified by:

writeInt in interface java.io.DataOutput

Throws:

java.io.IOException

readInt

public int readInt()
            throws java.io.EOFException,
                   java.io.IOException

Specified by:

readInt in interface java.io.DataInput

Throws:

java.io.EOFException

java.io.IOException

writeLong

public void writeLong(long v)
               throws java.io.IOException

Specified by:

writeLong in interface java.io.DataOutput

Throws:

java.io.IOException

readLong

public long readLong()
              throws java.io.EOFException,
                     java.io.IOException

Specified by:

readLong in interface java.io.DataInput

Throws:

java.io.EOFException

java.io.IOException

writeFloat

public void writeFloat(float v)
                throws java.io.IOException

Specified by:

writeFloat in interface java.io.DataOutput

Throws:

java.io.IOException

readFloat

public float readFloat()
                throws java.io.IOException

See the general contract of the readFloat method of DataInput.

Bytes for this operation are read from the contained input stream.

Specified by:

readFloat in interface java.io.DataInput

Returns:

the next four bytes of this input stream, interpreted as a float.

Throws:

java.io.EOFException - if this input stream reaches the end before reading four bytes.

java.io.IOException - if an I/O error occurs.

See Also:

DataInputStream.readInt(), Float.intBitsToFloat(int)

writeDouble

public void writeDouble(double v)
                 throws java.io.IOException

Specified by:

writeDouble in interface java.io.DataOutput

Throws:

java.io.IOException

readDouble

public double readDouble()
                  throws java.io.IOException

See the general contract of the readDouble method of DataInput.

Bytes for this operation are read from the contained input stream.

Specified by:

readDouble in interface java.io.DataInput

Returns:

the next eight bytes of this input stream, interpreted as a double.

Throws:

java.io.EOFException - if this input stream reaches the end before reading eight bytes.

java.io.IOException - if an I/O error occurs.

See Also:

DataInputStream.readLong(), Double.longBitsToDouble(long)

writeBytes

public void writeBytes(java.lang.String s)
                throws java.io.IOException

Specified by:

writeBytes in interface java.io.DataOutput

Throws:

java.io.IOException

writeChars

public void writeChars(java.lang.String s)
                throws java.io.IOException

Specified by:

writeChars in interface java.io.DataOutput

Throws:

java.io.IOException

writeUTF

public void writeUTF(java.lang.String s)
              throws java.io.IOException

Specified by:

writeUTF in interface java.io.DataOutput

Throws:

java.io.IOException

readLine

public java.lang.String readLine()
                          throws java.io.IOException

Specified by:

readLine in interface java.io.DataInput

Throws:

java.io.IOException

readUTF

public java.lang.String readUTF()
                         throws java.io.IOException

Specified by:

readUTF in interface java.io.DataInput

Throws:

java.io.IOException

seek

public void seek(long pos)
          throws java.io.IOException

Parameters:

pos -

Throws:

java.io.IOException

getPos

public long getPos()

Returns:

a long integer that the current postion inside the file or stream

skipBytes

public long skipBytes(long n)
               throws java.io.IOException

Parameters:

n -

Returns:

a long intger that indicates the number od bits skipped

Throws:

java.io.EOFException

java.io.IOException

getCapacity

public int getCapacity()

Returns:

an integer that indicates the capacity of the buffer

available

public long available()
               throws java.io.IOException

Returns the number of bytes that can be read from this buffer without blocking. The value returned is count - pos, which is the number of bytes remaining to be read from the input buffer.

Returns:

the number of bytes that can be read from the buffer without blocking.

Throws:

java.io.IOException

length

public long length()

Returns the number of bytes that can be read from this buffer, taking into account any buffering.

Returns:

The length of the stream, in bytes, or -1 if an I/O error ocurrs.

flush

public final void flush()
                 throws java.io.IOException

Data stored in the buff must be written in a file. Buffer is reseted to its initial state.

Throws:

java.io.IOException - If an I/O error ocurred.

close

public void close()
           throws java.io.IOException

Throws:

java.io.IOException

toString

public java.lang.String toString()

For debugging purpose.

Overrides:

toString in class java.lang.Object

setMode

private void setMode(java.lang.String mode)

read1

private final int read1()
                 throws java.io.IOException,
                        java.io.EOFException

Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned.

This read method cannot block.

Returns:

the next byte of this input stream as a int.

Throws:

java.io.EOFException - if this input stream has reached the end.

java.io.IOException - if an I/O error occurs.

readBuffer

private void readBuffer()
                 throws java.io.EOFException,
                        java.io.IOException

Throws:

java.io.EOFException

java.io.IOException

resizeBuffer

private void resizeBuffer(int newSize)