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.EOFException;
048import java.io.IOException;
049
050/**
051 * This abstract class defines the interface to perform random access I/O. It
052 * implements the <tt>BinaryDataInput</tt> and <tt>BinaryDataOutput</tt>
053 * interfaces so that binary data input/output can be performed.
054 *
055 * <P>This interface supports streams of up to 2 GB in length.
056 *
057 * @see BinaryDataInput
058 * @see BinaryDataOutput
059 * */
060public interface RandomAccessIO
061    extends BinaryDataInput, BinaryDataOutput {
062
063    /**
064     * Closes the I/O stream. Prior to closing the stream, any buffered data
065     * (at the bit and byte level) should be written.
066     *
067     * @exception IOException If an I/O error ocurred.
068     * */
069    public void close() throws IOException;
070
071    /**
072     * Returns the current position in the stream, which is the position from
073     * where the next byte of data would be read. The first byte in the stream
074     * is in position <tt>0</tt>.
075     *
076     * @return The offset of the current position, in bytes.
077     *
078     * @exception IOException If an I/O error ocurred.
079     * */
080    public int getPos() throws IOException;
081
082    /**
083     * Returns the current length of the stream, in bytes, taking into account
084     * any buffering.
085     *
086     * @return The length of the stream, in bytes.
087     *
088     * @exception IOException If an I/O error ocurred.
089     * */
090    public int length() throws IOException;
091
092    /**
093     * Moves the current position for the next read or write operation to
094     * offset. The offset is measured from the beginning of the stream. The
095     * offset may be set beyond the end of the file, if in write mode. Setting
096     * the offset beyond the end of the file does not change the file
097     * length. The file length will change only by writing after the offset
098     * has been set beyond the end of the file.
099     *
100     * @param off The offset where to move to.
101     *
102     * @exception EOFException If in read-only and seeking beyond EOF.
103     *
104     * @exception IOException If an I/O error ocurred.
105     * */
106    public void seek(int off) throws IOException;
107
108    /**
109     * Reads a byte of data from the stream. Prior to reading, the stream is
110     * realigned at the byte level.
111     *
112     * @return The byte read, as an int.
113     *
114     * @exception EOFException If the end-of file was reached.
115     *
116     * @exception IOException If an I/O error ocurred.
117     * */
118    public int read() throws EOFException, IOException;
119
120    /**
121     * Reads up to len bytes of data from this file into an array of
122     * bytes. This method reads repeatedly from the stream until all the bytes
123     * are read. This method blocks until all the bytes are read, the end of
124     * the stream is detected, or an exception is thrown.
125     *
126     * @param b The buffer into which the data is to be read. It must be long
127     * enough.
128     *
129     * @param off The index in 'b' where to place the first byte read.
130     *
131     * @param len The number of bytes to read.
132     *
133     * @exception EOFException If the end-of file was reached before
134     * getting all the necessary data.
135     *
136     * @exception IOException If an I/O error ocurred.
137     * */
138    public void readFully(byte b[], int off, int len) throws IOException;
139
140    /**
141     * Writes a byte to the stream. Prior to writing, the stream is realigned
142     * at the byte level.
143     *
144     * @param b The byte to write. The lower 8 bits of <tt>b</tt> are
145     * written.
146     *
147     * @exception IOException If an I/O error ocurred.
148     * */
149    public void write(int b) throws IOException;
150}