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* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
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/*
* $RCSfile: ByteInputBuffer.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:05 $
* $State: Exp $
*
* Class: ByteInputBuffer
*
* Description: Provides buffering for byte based input, similar
* to the standard class ByteArrayInputStream
*
* the old jj2000.j2k.io.ByteArrayInput class by
* Diego SANTA CRUZ, Apr-26-1999
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
*
*
*
*/
package jj2000.j2k.entropy.decoder;
import java.io.*;
/**
* This class provides a byte input facility from byte buffers. It is similar
* to the ByteArrayInputStream class, but adds the possibility to add data to
* the stream after the creation of the object.
*
* <P>Unlike the ByteArrayInputStream this class is not thread safe (i.e. no
* two threads can use the same object at the same time, but different objects
* may be used in different threads).
*
* <P>This class can modify the contents of the buffer given to the
* constructor, when the addByteArray() method is called.
*
* @see InputStream
* */
public class ByteInputBuffer {
/** The byte array containing the data */
private byte buf[];
/** The index one greater than the last valid character in the input
* stream buffer */
private int count;
/** The index of the next character to read from the input stream buffer
* */
private int pos;
/**
* Creates a new byte array input stream that reads data from the
* specified byte array. The byte array is not copied.
*
* @param buf the input buffer.
*/
public ByteInputBuffer(byte buf[]){
this.buf = buf;
count = buf.length;
}
/**
* Creates a new byte array input stream that reads data from the
* specified byte array. Up to length characters are to be read
* from the byte array, starting at the indicated offset.
*
* <P>The byte array is not copied.
*
* @param buf the input buffer.
*
* @param offset the offset in the buffer of the first byte to
* read.
*
* @param length the maximum number of bytes to read from the
* buffer.
*/
public ByteInputBuffer(byte buf[], int offset, int length) {
this.buf = buf;
pos = offset;
count = offset+length;
}
/**
* Sets the underlying buffer byte array to the given one, with the given
* offset and length. If 'buf' is null then the current byte buffer is
* assumed. If 'offset' is negative, then it will be assumed to be
* 'off+len', where 'off' and 'len' are the offset and length of the
* current byte buffer.
*
* <P>The byte array is not copied.
*
* @param buf the input buffer. If null it is the current input buffer.
*
* @param offset the offset in the buffer of the first byte to read. If
* negative it is assumed to be the byte just after the end of the current
* input buffer, only permitted if 'buf' is null.
*
* @param length the maximum number of bytes to read frmo the buffer.
*/
public void setByteArray(byte buf[], int offset, int length) {
// In same buffer?
if (buf == null) {
if (length < 0 || count+length>this.buf.length) {
throw new IllegalArgumentException();
}
if (offset < 0) {
pos = count;
count += length;
} else {
count = offset+length;
pos = offset;
}
} else { // New input buffer
if (offset < 0 || length < 0 || offset+length > buf.length) {
throw new IllegalArgumentException();
}
this.buf = buf;
count = offset+length;
pos = offset;
}
}
/**
* Adds the specified data to the end of the byte array stream. This
* method modifies the byte array buffer. It can also discard the already
* read input.
*
* @param data The data to add. The data is copied.
*
* @param off The index, in data, of the first element to add to
* the stream.
*
* @param len The number of elements to add to the array.
*
*
* */
public synchronized void addByteArray(byte data[], int off, int len) {
// Check integrity
if (len < 0 || off < 0 || len+off > buf.length) {
throw new IllegalArgumentException();
}
// Copy new data
if (count+len <= buf.length) { // Enough place in 'buf'
System.arraycopy(data,off,buf,count,len);
count += len;
} else {
if (count-pos+len <= buf.length) {
// Enough place in 'buf' if we move input data
// Move buffer
System.arraycopy(buf,pos,buf,0,count-pos);
} else { // Not enough place in 'buf', use new buffer
byte [] oldbuf = buf;
buf = new byte[count-pos+len];
// Copy buffer
System.arraycopy(oldbuf,count,buf,0,count-pos);
}
count -= pos;
pos = 0;
// Copy new data
System.arraycopy(data,off,buf,count,len);
count += len;
}
}
/**
* Reads the next byte of data from this input stream. The value
* byte 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
* EOFException exception is thrown.
*
* <P>This method is not synchronized, so it is not thread safe.
*
* @return The byte read in the range 0-255.
*
* @exception EOFException If the end of the stream is reached.
*
*
* */
public int readChecked() throws IOException {
if (pos < count) {
return (int)buf[pos++] & 0xFF;
} else {
throw new EOFException();
}
}
/**
* Reads the next byte of data from this input stream. The value byte 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, -1 is returned.
*
* <P>This method is not synchronized, so it is not thread safe.
*
* @return The byte read in the range 0-255, or -1 if the end of stream
* has been reached.
*
*
* */
public int read() {
if (pos < count) {
return (int)buf[pos++] & 0xFF;
} else {
return -1;
}
}
}