Package it.unimi.dsi.io

Class SegmentedInputStream

java.lang.Object

java.io.InputStream

it.unimi.dsi.fastutil.io.MeasurableInputStream

it.unimi.dsi.io.SegmentedInputStream

All Implemented Interfaces:

MeasurableStream, Closeable, AutoCloseable

public class SegmentedInputStream
extends MeasurableInputStream

Exhibits a single InputStream as a number of streams divided into reset()-separated segments.

An instance of this class wraps a given input stream (usually a replicable one, such as a FileInputStream) and exposes its contents as a number of separated input streams. Each such stream, called a block, is defined by a start and a stop position (gaps between blocks are possible). Inside each block we can have one or more segments: each segment is again a separate input stream, but calling reset() moves from one segment to the following one, whereas calling close() moves from a block to the following one.

An instance of this class is enriched with blocks by calling addBlock(long[]). This can also be done on-the-fly, while the underlying input stream is being scanned.

Author:

Alessio Orlandi, Luca Natali, Sebastiano Vigna

Constructor Summary

Constructors

Constructor	Description
SegmentedInputStream(InputStream in)	Creates a segmented input stream with no markers.
SegmentedInputStream(InputStream in, long... delimiter)	Creats a stream with one marker in.

Method Summary

Modifier and Type	Method	Description
void	addBlock(long... delimiter)	Adds a new block defined by its array of segment delimiters.
int	available()
void	close()	Skips to the next block, closing this segmented input stream if there are no more blocks.
boolean	hasMoreBlocks()	Checks whether there are more blocks.
long	length()
void	nextBlock()	Skips to the first segment of the next block, if any.
long	position()
int	read()
int	read(byte[] b, int off, int len)
void	reset()	Moves into the next segment of the current block.
long	skip(long n)

Methods inherited from class java.io.InputStream

mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Methods inherited from class java.lang.Object

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

Constructor Details

SegmentedInputStream

public SegmentedInputStream(InputStream in)

Creates a segmented input stream with no markers.

Parameters:

in - the underlying input stream.

SegmentedInputStream

public SegmentedInputStream(InputStream in,
 long... delimiter)
                     throws NullPointerException,
IOException,
IllegalStateException

Creats a stream with one marker in.

Parameters:

in - the underlying input stream.

delimiter - an array of segment delimiters.

Throws:

NullPointerException

IOException

IllegalStateException

Method Details

nextBlock

public void nextBlock()
               throws IOException

Skips to the first segment of the next block, if any. In such case, it returns true, or false otherwise.

Throws:

IOException

hasMoreBlocks

public boolean hasMoreBlocks()

Checks whether there are more blocks.

Returns:

true if we there are more blocks.

addBlock

public void addBlock(long... delimiter)
              throws IllegalArgumentException,
IOException

Adds a new block defined by its array of segment delimiters.

The block has length defined by the difference between the last and first delimiter.

This method performs the initial call to nextBlock() when the first marker is put in.

Parameters:

delimiter - a list of segment delimiters.

Throws:

IllegalArgumentException - if the elements of delimiter are negative or not increasing.

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

read

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

Overrides:

read in class InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class InputStream

Throws:

IOException

available

public int available()
              throws IOException

Overrides:

available in class InputStream

Throws:

IOException

length

public long length()
            throws IOException

Throws:

IOException

position

public long position()
              throws IOException

Throws:

IOException

close

public void close()
           throws IOException

Skips to the next block, closing this segmented input stream if there are no more blocks.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class InputStream

Throws:

IOException

reset

public void reset()
           throws IOException

Moves into the next segment of the current block.

Overrides:

reset in class InputStream

Throws:

IOException