001/*
002 * $RCSfile: RandomAccessIO.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:16 $
005 * $State: Exp $
006 *
007 * Interface:           RandomAccessIO.java
008 *
009 * Description:         Interface definition for random access I/O.
010 *
011 *
012 *
013 * COPYRIGHT:
014 *
015 * This software module was originally developed by Raphaël Grosbois and
016 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
017 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
018 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
019 * Centre France S.A) in the course of development of the JPEG2000
020 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
021 * software module is an implementation of a part of the JPEG 2000
022 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
023 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
024 * Partners) agree not to assert against ISO/IEC and users of the JPEG
025 * 2000 Standard (Users) any of their rights under the copyright, not
026 * including other intellectual property rights, for this software module
027 * with respect to the usage by ISO/IEC and Users of this software module
028 * or modifications thereof for use in hardware or software products
029 * claiming conformance to the JPEG 2000 Standard. Those intending to use
030 * this software module in hardware or software products are advised that
031 * their use may infringe existing patents. The original developers of
032 * this software module, JJ2000 Partners and ISO/IEC assume no liability
033 * for use of this software module or modifications thereof. No license
034 * or right to this software module is granted for non JPEG 2000 Standard
035 * conforming products. JJ2000 Partners have full right to use this
036 * software module for his/her own purpose, assign or donate this
037 * software module to any third party and to inhibit third parties from
038 * using this software module for non JPEG 2000 Standard conforming
039 * products. This copyright notice must be included in all copies or
040 * derivative works of this software module.
041 *
042 * Copyright (c) 1999/2000 JJ2000 Partners.
043 */
044
045package jj2000.j2k.io;
046
047import java.io.*;
048
049/**
050 * This abstract class defines the interface to perform random access I/O. It
051 * implements the <tt>BinaryDataInput</tt> and <tt>BinaryDataOutput</tt>
052 * interfaces so that binary data input/output can be performed.
053 *
054 * <P>This interface supports streams of up to 2 GB in length.
055 *
056 * @see BinaryDataInput
057 * @see BinaryDataOutput
058 * */
059public interface RandomAccessIO
060    extends BinaryDataInput, BinaryDataOutput {
061
062    /**
063     * Closes the I/O stream. Prior to closing the stream, any buffered data
064     * (at the bit and byte level) should be written.
065     *
066     * @exception IOException If an I/O error ocurred.
067     * */
068    public void close() throws IOException;
069
070    /**
071     * Returns the current position in the stream, which is the position from
072     * where the next byte of data would be read. The first byte in the stream
073     * is in position <tt>0</tt>.
074     *
075     * @return The offset of the current position, in bytes.
076     *
077     * @exception IOException If an I/O error ocurred.
078     * */
079    public int getPos() throws IOException;
080
081    /**
082     * Returns the current length of the stream, in bytes, taking into account
083     * any buffering.
084     *
085     * @return The length of the stream, in bytes.
086     *
087     * @exception IOException If an I/O error ocurred.
088     * */
089    public int length() throws IOException;
090
091    /**
092     * Moves the current position for the next read or write operation to
093     * offset. The offset is measured from the beginning of the stream. The
094     * offset may be set beyond the end of the file, if in write mode. Setting
095     * the offset beyond the end of the file does not change the file
096     * length. The file length will change only by writing after the offset
097     * has been set beyond the end of the file.
098     *
099     * @param off The offset where to move to.
100     *
101     * @exception EOFException If in read-only and seeking beyond EOF.
102     *
103     * @exception IOException If an I/O error ocurred.
104     * */
105    public void seek(int off) throws IOException;
106
107    /**
108     * Reads a byte of data from the stream. Prior to reading, the stream is
109     * realigned at the byte level.
110     *
111     * @return The byte read, as an int.
112     *
113     * @exception EOFException If the end-of file was reached.
114     *
115     * @exception IOException If an I/O error ocurred.
116     * */
117    public int read() throws EOFException, IOException;
118
119    /**
120     * Reads up to len bytes of data from this file into an array of
121     * bytes. This method reads repeatedly from the stream until all the bytes
122     * are read. This method blocks until all the bytes are read, the end of
123     * the stream is detected, or an exception is thrown.
124     *
125     * @param b The buffer into which the data is to be read. It must be long
126     * enough.
127     *
128     * @param off The index in 'b' where to place the first byte read.
129     *
130     * @param len The number of bytes to read.
131     *
132     * @exception EOFException If the end-of file was reached before
133     * getting all the necessary data.
134     *
135     * @exception IOException If an I/O error ocurred.
136     * */
137    public void readFully(byte b[], int off, int len) throws IOException;
138
139    /**
140     * Writes a byte to the stream. Prior to writing, the stream is realigned
141     * at the byte level.
142     *
143     * @param b The byte to write. The lower 8 bits of <tt>b</tt> are
144     * written.
145     *
146     * @exception IOException If an I/O error ocurred.
147     * */
148    public void write(int b) throws IOException;
149}