edu.illinois.cs.cogcomp.lbjava.io

Class HexInputStream

java.lang.Object

java.io.InputStream

edu.illinois.cs.cogcomp.lbjava.io.HexInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class HexInputStream
extends InputStream

This class receives input from another InputStream assuming that data is little endian, hexidecimal text, converts that text to bytes, and makes those bytes available through its interface. The most common usage of this class will involve passing it to the constructor of another InputStream. For instance:

 ObjectInputStream ois = new ObjectInputStream(new GZIPInputStream(new HexInputStream(
         new FileInputStream(fileName))));
 

Author:

Nick Rizzolo

See Also:

HexOutputStream

Constructor Summary

Constructors

Constructor and Description
HexInputStream(InputStream i) Initializes this stream with another input stream.

Method Summary

Modifier and Type	Method and Description
int	available() Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
int	read() Reads the next byte of data from the input stream.
int	read(byte[] b) This method has the same effect as read(b, 0, b.length).
int	read(byte[] b, int off, int len) Reads up to len bytes of data from another input stream into an array of bytes.
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from this input stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

HexInputStream

public HexInputStream(InputStream i)

Initializes this stream with another input stream.

Parameters:

i - The input stream from which yet-to-be-converted input should be received.

Method Detail

read

public int read()
         throws IOException

Reads the next byte of data from the input stream. The value 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.

Specified by:

read in class InputStream

Returns:

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

Throws:

IOException

read

public int read(byte[] b)
         throws IOException

This method has the same effect as read(b, 0, b.length).

Overrides:

read in class InputStream

Parameters:

b - A buffer in which the converted input is stored.

Returns:

The total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream was previously reached.

Throws:

IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Reads up to len bytes of data from another input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

This method blocks until input data is available, end of file is detected, or an exception is thrown.

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 read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

The first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

In every case, elements b[0] through b[off-1] and elements b[off+len] through b[b.length-1] are unaffected.

If the first byte cannot be read for any reason other than end of file, then an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed.

Overrides:

read in class InputStream

Parameters:

b - A buffer into which the converted input is stored.

off - The offset in the buffer at which to begin writing.

len - The amount of bytes to be received and written into the buffer.

Returns:

The total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.

Overrides:

skip in class InputStream

Parameters:

n - The number of bytes to be skipped.

Returns:

The actual number of bytes skipped.

Throws:

IOException

available

public int available()
              throws IOException

Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or or another thread.

Overrides:

available in class InputStream

Returns:

The number of bytes that can be read from this input stream without blocking.

Throws:

IOException

close

public void close()
           throws IOException

Closes this input stream and releases any system resources associated with the stream.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

mark

public void mark(int readlimit)

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. The readlimit argument tells this input stream to allow that many bytes to be read before the mark position gets invalidated. The general contract of mark is that, if the method markSupported returns true, the stream somehow remembers all the bytes read after the call to mark and stands ready to supply those same bytes again if and whenever the method reset is called. However, the stream is not required to remember any data at all if more than readlimit bytes are read from the stream before reset is called.

Overrides:

mark in class InputStream

Parameters:

readlimit - The maximum limit of bytes that can be read before the mark position becomes invalid.

reset

public void reset()
           throws IOException

Repositions this stream to the position at the time the mark method was last called on this input stream.

Overrides:

reset in class InputStream

Throws:

IOException

markSupported

public boolean markSupported()

Tests if this input stream supports the mark and reset methods. Whether or not mark and reset are supported is an invariant property of the provided input stream instance.

Overrides:

markSupported in class InputStream

Returns:

true iff the provided input stream instance supports the mark and reset methods.