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:
045: package jj2000.j2k.io;
046:
047: import 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: * */
059: public interface RandomAccessIO extends BinaryDataInput,
060: 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)
138: 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: }
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