com.phloc.web.fileupload.MultipartStream Maven / Gradle / Ivy
/**
* Copyright (C) 2006-2015 phloc systems
* http://www.phloc.com
* office[at]phloc[dot]com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.phloc.web.fileupload;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.phloc.commons.ValueEnforcer;
import com.phloc.commons.charset.CharsetManager;
import com.phloc.commons.io.streams.NonBlockingByteArrayOutputStream;
import com.phloc.commons.system.SystemHelper;
import com.phloc.web.fileupload.util.ICloseable;
import com.phloc.web.fileupload.util.Streams;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
*
* Low level API for processing file uploads.
*
* This class can be used to process data streams conforming to MIME 'multipart'
* format as defined in RFC
* 1867. Arbitrarily large amounts of data in the stream can be processed
* under constant memory usage.
*
* The format of the stream is defined in the following way:
*
* multipart-body := preamble 1*encapsulation close-delimiter epilogue
* encapsulation := delimiter body CRLF
* delimiter := "--" boundary CRLF
* close-delimiter := "--" boudary "--"
* preamble := <ignore>
* epilogue := <ignore>
* body := header-part CRLF body-part
* header-part := 1*header CRLF
* header := header-name ":" header-value
* header-name := <printable ascii characters except ":">
* header-value := <any ascii characters except CR & LF>
* body-data := <arbitrary data>
*
*
* Note that body-data can contain another mulipart entity. There is limited
* support for single pass processing of such nested streams. The nested stream
* is required to have a boundary token of the same length as
* the parent stream (see {@link #setBoundary(byte[])}).
*
* Here is an example of usage of this class.
*
*
* try
* {
* MultipartStream multipartStream = new MultipartStream (input, boundary);
* boolean nextPart = multipartStream.skipPreamble ();
* OutputStream output;
* while (nextPart)
* {
* String header = multipartStream.readHeaders ();
* // process headers
* // create some output stream
* multipartStream.readBodyData (output);
* nextPart = multipartStream.readBoundary ();
* }
* }
* catch (MultipartStream.MalformedStreamException e)
* {
* // the stream failed to follow required syntax
* }
* catch (IOException e)
* {
* // a read or write error occurred
* }
*
*
* @author Rafal Krzewski
* @author Martin Cooper
* @author Sean C. Sullivan
* @version $Id: MultipartStream.java 735374 2009-01-18 02:18:45Z jochen $
*/
public final class MultipartStream
{
/**
* Internal class, which is used to invoke the {@link IProgressListener}.
*/
public static final class ProgressNotifier
{
private static final Logger s_aLogger = LoggerFactory.getLogger (MultipartStream.ProgressNotifier.class);
/**
* The listener to invoke.
*/
private final IProgressListener m_aListener;
/**
* Number of expected bytes, if known, or -1.
*/
private final long m_nContentLength;
/**
* Number of bytes, which have been read so far.
*/
private long m_nBytesRead;
/**
* Number of items, which have been read so far.
*/
private int m_nItems;
/**
* Creates a new instance with the given listener and content length.
*
* @param pListener
* The listener to invoke.
* @param pContentLength
* The expected content length.
*/
ProgressNotifier (@Nullable final IProgressListener pListener, final long pContentLength)
{
if (pListener != null)
s_aLogger.info ("setting listener " + pListener.getClass ().getName ());
this.m_aListener = pListener;
this.m_nContentLength = pContentLength;
}
/**
* Called to indicate that bytes have been read.
*
* @param pBytes
* Number of bytes, which have been read.
*/
void noteBytesRead (@Nonnegative final int pBytes)
{
ValueEnforcer.isGE0 (pBytes, "Bytes");
/*
* Indicates, that the given number of bytes have been read from the input
* stream.
*/
this.m_nBytesRead += pBytes;
_notifyListener ();
}
/**
* Called to indicate, that a new file item has been detected.
*/
void noteItem ()
{
++this.m_nItems;
_notifyListener ();
}
/**
* Called for notifying the listener.
*/
private void _notifyListener ()
{
if (this.m_aListener != null)
{
this.m_aListener.update (this.m_nBytesRead, this.m_nContentLength, this.m_nItems);
}
}
}
// ----------------------------------------------------- Manifest constants
/**
* The Carriage Return ASCII character value.
*/
public static final byte CR = 0x0D;
/**
* The Line Feed ASCII character value.
*/
public static final byte LF = 0x0A;
/**
* The dash (-) ASCII character value.
*/
public static final byte DASH = 0x2D;
/**
* The maximum length of header-part that will be processed (10
* kilobytes = 10240 bytes.).
*/
public static final int HEADER_PART_SIZE_MAX = 10240;
/**
* The default length of the buffer used for processing a request.
*/
private static final int DEFAULT_BUFSIZE = 4096;
/**
* A byte sequence that marks the end of header-part (
* CRLFCRLF).
*/
private static final byte [] HEADER_SEPARATOR = { CR, LF, CR, LF };
/**
* A byte sequence that that follows a delimiter that will be followed by an
* encapsulation (CRLF).
*/
private static final byte [] FIELD_SEPARATOR = { CR, LF };
/**
* A byte sequence that that follows a delimiter of the last encapsulation in
* the stream (--).
*/
private static final byte [] STREAM_TERMINATOR = { DASH, DASH };
/**
* A byte sequence that precedes a boundary (CRLF--).
*/
private static final byte [] BOUNDARY_PREFIX = { CR, LF, DASH, DASH };
// ----------------------------------------------------------- Data members
/**
* The input stream from which data is read.
*/
private final InputStream m_aInput;
/**
* The length of the boundary token plus the leading CRLF--.
*/
private int m_nBoundaryLength;
/**
* The amount of data, in bytes, that must be kept in the buffer in order to
* detect delimiters reliably.
*/
private final int m_nKeepRegion;
/**
* The byte sequence that partitions the stream.
*/
private final byte [] m_aBoundary;
/**
* The length of the buffer used for processing the request.
*/
private final int m_nBufSize;
/**
* The buffer used for processing the request.
*/
private final byte [] m_aBuffer;
/**
* The index of first valid character in the buffer.
* 0 <= head < bufSize
*/
private int m_nHead;
/**
* The index of last valid character in the buffer + 1.
* 0 <= tail <= bufSize
*/
private int m_nTail;
/**
* The content encoding to use when reading headers.
*/
private String m_sHeaderEncoding;
/**
* The progress notifier, if any, or null.
*/
private final ProgressNotifier m_aNotifier;
// ----------------------------------------------------------- Constructors
/**
*
* Constructs a MultipartStream with a custom size buffer.
*
* Note that the buffer must be at least big enough to contain the boundary
* string, plus 4 characters for CR/LF and double dash, plus at least one byte
* of data. Too small a buffer size setting will degrade performance.
*
* @param input
* The InputStream to serve as a data source.
* @param boundary
* The token used for dividing the stream into
* encapsulations.
* @param bufSize
* The size of the buffer to be used, in bytes.
* @param pNotifier
* The notifier, which is used for calling the progress listener, if
* any.
* @see #MultipartStream(InputStream, byte[],
* MultipartStream.ProgressNotifier)
*/
MultipartStream (final InputStream input, final byte [] boundary, final int bufSize, final ProgressNotifier pNotifier)
{
this.m_aInput = input;
this.m_nBufSize = bufSize;
this.m_aBuffer = new byte [bufSize];
this.m_aNotifier = pNotifier;
// We prepend CR/LF to the boundary to chop trailng CR/LF from
// body-data tokens.
this.m_aBoundary = new byte [boundary.length + BOUNDARY_PREFIX.length];
this.m_nBoundaryLength = boundary.length + BOUNDARY_PREFIX.length;
this.m_nKeepRegion = this.m_aBoundary.length;
System.arraycopy (BOUNDARY_PREFIX, 0, this.m_aBoundary, 0, BOUNDARY_PREFIX.length);
System.arraycopy (boundary, 0, this.m_aBoundary, BOUNDARY_PREFIX.length, boundary.length);
this.m_nHead = 0;
this.m_nTail = 0;
}
/**
*
* Constructs a MultipartStream with a default size buffer.
*
* @param input
* The InputStream to serve as a data source.
* @param boundary
* The token used for dividing the stream into
* encapsulations.
* @param pNotifier
* An object for calling the progress listener, if any.
* @see #MultipartStream(InputStream, byte[], int,
* MultipartStream.ProgressNotifier)
*/
MultipartStream (final InputStream input, final byte [] boundary, final ProgressNotifier pNotifier)
{
this (input, boundary, DEFAULT_BUFSIZE, pNotifier);
}
// --------------------------------------------------------- Public methods
/**
* Retrieves the character encoding used when reading the headers of an
* individual part. When not specified, or null, the platform
* default encoding is used.
*
* @return The encoding used to read part headers.
*/
@Nullable
public String getHeaderEncoding ()
{
return this.m_sHeaderEncoding;
}
/**
* Specifies the character encoding to be used when reading the headers of
* individual parts. When not specified, or null, the platform
* default encoding is used.
*
* @param encoding
* The encoding used to read part headers.
*/
public void setHeaderEncoding (@Nullable final String encoding)
{
this.m_sHeaderEncoding = encoding;
}
/**
* Reads a byte from the buffer, and refills it as necessary.
*
* @return The next byte from the input stream.
* @throws IOException
* if there is no more data available.
*/
public byte readByte () throws IOException
{
// Buffer depleted ?
if (this.m_nHead == this.m_nTail)
{
this.m_nHead = 0;
// Refill.
this.m_nTail = this.m_aInput.read (this.m_aBuffer, this.m_nHead, this.m_nBufSize);
if (this.m_nTail == -1)
{
// No more data available.
throw new IOException ("No more data is available");
}
if (this.m_aNotifier != null)
{
this.m_aNotifier.noteBytesRead (this.m_nTail);
}
}
return this.m_aBuffer[this.m_nHead++];
}
/**
* Skips a boundary token, and checks whether more
* encapsulations are contained in the stream.
*
* @return true if there are more encapsulations in this stream;
* false otherwise.
* @throws MalformedStreamException
* if the stream ends unexpecetedly or fails to follow required
* syntax.
*/
public boolean readBoundary () throws MalformedStreamException
{
final byte [] marker = new byte [2];
boolean nextChunk = false;
this.m_nHead += this.m_nBoundaryLength;
try
{
marker[0] = readByte ();
if (marker[0] == LF)
{
// Work around IE5 Mac bug with input type=image.
// Because the boundary delimiter, not including the trailing
// CRLF, must not appear within any file (RFC 2046, section
// 5.1.1), we know the missing CR is due to a buggy browser
// rather than a file containing something similar to a
// boundary.
return true;
}
marker[1] = readByte ();
if (arrayequals (marker, STREAM_TERMINATOR, 2))
{
nextChunk = false;
}
else
if (arrayequals (marker, FIELD_SEPARATOR, 2))
{
nextChunk = true;
}
else
{
throw new MalformedStreamException ("Unexpected characters follow a boundary");
}
}
catch (final IOException e)
{
throw new MalformedStreamException ("Stream ended unexpectedly", e);
}
return nextChunk;
}
/**
*
* Changes the boundary token used for partitioning the stream.
*
* This method allows single pass processing of nested multipart streams.
*
* The boundary token of the nested stream is required to be of
* the same length as the boundary token in parent stream.
*
* Restoring the parent stream boundary token after processing of a nested
* stream is left to the application.
*
* @param boundary
* The boundary to be used for parsing of the nested stream.
* @throws IllegalBoundaryException
* if the boundary has a different length than the one
* being currently parsed.
*/
public void setBoundary (final byte [] boundary) throws IllegalBoundaryException
{
if (boundary.length != this.m_nBoundaryLength - BOUNDARY_PREFIX.length)
{
throw new IllegalBoundaryException ("The length of a boundary token can not be changed");
}
System.arraycopy (boundary, 0, this.m_aBoundary, BOUNDARY_PREFIX.length, boundary.length);
}
/**
*
* Reads the header-part of the current
* encapsulation.
*
* Headers are returned verbatim to the input stream, including the trailing
* CRLF marker. Parsing is left to the application.
*
* TODO allow limiting maximum header size to protect against
* abuse.
*
* @return The header-part of the current encapsulation.
* @throws MalformedStreamException
* if the stream ends unexpectedly.
*/
public String readHeaders () throws MalformedStreamException
{
int i = 0;
byte b;
// to support multi-byte characters
final NonBlockingByteArrayOutputStream baos = new NonBlockingByteArrayOutputStream ();
try
{
int size = 0;
while (i < HEADER_SEPARATOR.length)
{
try
{
b = readByte ();
}
catch (final IOException e)
{
throw new MalformedStreamException ("Stream ended unexpectedly", e);
}
if (++size > HEADER_PART_SIZE_MAX)
{
throw new MalformedStreamException ("Header section has more than " +
HEADER_PART_SIZE_MAX +
" bytes (maybe it is not properly terminated)");
}
if (b == HEADER_SEPARATOR[i])
{
i++;
}
else
{
i = 0;
}
baos.write (b);
}
String headers = null;
if (this.m_sHeaderEncoding != null)
{
headers = baos.getAsString (CharsetManager.getCharsetFromName (this.m_sHeaderEncoding));
}
else
{
headers = baos.getAsString (SystemHelper.getSystemCharset ());
}
return headers;
}
finally
{
baos.close ();
}
}
/**
*
* Reads body-data from the current encapsulation
* and writes its contents into the output Stream.
*
* Arbitrary large amounts of data can be processed by this method using a
* constant size buffer. (see
* {@link #MultipartStream(InputStream,byte[],int, MultipartStream.ProgressNotifier)
* constructor}).
*
* @param output
* The Stream to write data into. May be null, in which
* case this method is equivalent to {@link #discardBodyData()}.
* @return the amount of data written.
* @throws MalformedStreamException
* if the stream ends unexpectedly.
* @throws IOException
* if an i/o error occurs.
*/
public int readBodyData (final OutputStream output) throws MalformedStreamException, IOException
{
final InputStream istream = newInputStream ();
return (int) Streams.copy (istream, output, false);
}
/**
* Creates a new {@link ItemInputStream}.
*
* @return A new instance of {@link ItemInputStream}.
*/
@Nonnull
ItemInputStream newInputStream ()
{
return new ItemInputStream ();
}
/**
*
* Reads body-data from the current encapsulation
* and discards it.
*
* Use this method to skip encapsulations you don't need or don't understand.
*
* @return The amount of data discarded.
* @throws MalformedStreamException
* if the stream ends unexpectedly.
* @throws IOException
* if an i/o error occurs.
*/
public int discardBodyData () throws MalformedStreamException, IOException
{
return readBodyData (null);
}
/**
* Finds the beginning of the first encapsulation.
*
* @return true if an encapsulation was found in the
* stream.
* @throws IOException
* if an i/o error occurs.
*/
public boolean skipPreamble () throws IOException
{
// First delimiter may be not preceeded with a CRLF.
System.arraycopy (this.m_aBoundary, 2, this.m_aBoundary, 0, this.m_aBoundary.length - 2);
this.m_nBoundaryLength = this.m_aBoundary.length - 2;
try
{
// Discard all data up to the delimiter.
discardBodyData ();
// Read boundary - if succeded, the stream contains an
// encapsulation.
return readBoundary ();
}
catch (final MalformedStreamException e)
{
return false;
}
finally
{
// Restore delimiter.
System.arraycopy (this.m_aBoundary, 0, this.m_aBoundary, 2, this.m_aBoundary.length - 2);
this.m_nBoundaryLength = this.m_aBoundary.length;
this.m_aBoundary[0] = CR;
this.m_aBoundary[1] = LF;
}
}
/**
* Compares count first bytes in the arrays a and
* b.
*
* @param a
* The first array to compare.
* @param b
* The second array to compare.
* @param count
* How many bytes should be compared.
* @return true if count first bytes in arrays
* a and b are equal.
*/
public static boolean arrayequals (final byte [] a, final byte [] b, final int count)
{
for (int i = 0; i < count; i++)
{
if (a[i] != b[i])
{
return false;
}
}
return true;
}
/**
* Searches for a byte of specified value in the buffer, starting
* at the specified position.
*
* @param value
* The value to find.
* @param pos
* The starting position for searching.
* @return The position of byte found, counting from beginning of the
* buffer, or -1 if not found.
*/
protected int findByte (final byte value, final int pos)
{
for (int i = pos; i < this.m_nTail; i++)
{
if (this.m_aBuffer[i] == value)
{
return i;
}
}
return -1;
}
/**
* Searches for the boundary in the buffer region
* delimited by head and tail.
*
* @return The position of the boundary found, counting from the beginning of
* the buffer, or -1 if not found.
*/
protected int findSeparator ()
{
int first;
int match = 0;
final int maxpos = this.m_nTail - this.m_nBoundaryLength;
for (first = this.m_nHead; first <= maxpos && match != this.m_nBoundaryLength; first++)
{
first = findByte (this.m_aBoundary[0], first);
if (first == -1 || first > maxpos)
{
return -1;
}
for (match = 1; match < this.m_nBoundaryLength; match++)
{
if (this.m_aBuffer[first + match] != this.m_aBoundary[match])
{
break;
}
}
}
if (match == this.m_nBoundaryLength)
{
return first - 1;
}
return -1;
}
/**
* Thrown to indicate that the input stream fails to follow the required
* syntax.
*/
public static final class MalformedStreamException extends IOException
{
/**
* Constructs a MalformedStreamException with no detail
* message.
*/
public MalformedStreamException ()
{
super ();
}
/**
* Constructs an MalformedStreamException with the specified
* detail message.
*
* @param message
* The detail message.
*/
public MalformedStreamException (final String message)
{
super (message);
}
/**
* Constructs an MalformedStreamException with the specified
* detail message.
*
* @param message
* The detail message.
* @param aCause
* The cause of the exception
*/
public MalformedStreamException (final String message, final Throwable aCause)
{
super (message, aCause);
}
}
/**
* Thrown upon attempt of setting an invalid boundary token.
*/
public static final class IllegalBoundaryException extends IOException
{
/**
* Constructs an IllegalBoundaryException with no detail
* message.
*/
public IllegalBoundaryException ()
{
super ();
}
/**
* Constructs an IllegalBoundaryException with the specified
* detail message.
*
* @param message
* The detail message.
*/
public IllegalBoundaryException (final String message)
{
super (message);
}
}
/**
* An {@link InputStream} for reading an items contents.
*/
public final class ItemInputStream extends InputStream implements ICloseable
{
/**
* The number of bytes, which have been read so far.
*/
private long m_nTotal;
/**
* The number of bytes, which must be hold, because they might be a part of
* the boundary.
*/
private int m_nPad;
/**
* The current offset in the buffer.
*/
private int m_nPos;
/**
* Whether the stream is already closed.
*/
private boolean m_bClosed;
/**
* Creates a new instance.
*/
ItemInputStream ()
{
_findSeparator ();
}
/**
* Called for finding the separator.
*/
private void _findSeparator ()
{
this.m_nPos = MultipartStream.this.findSeparator ();
if (this.m_nPos == -1)
{
if (MultipartStream.this.m_nTail - MultipartStream.this.m_nHead > MultipartStream.this.m_nKeepRegion)
this.m_nPad = MultipartStream.this.m_nKeepRegion;
else
this.m_nPad = MultipartStream.this.m_nTail - MultipartStream.this.m_nHead;
}
}
/**
* Returns the number of bytes, which have been read by the stream.
*
* @return Number of bytes, which have been read so far.
*/
public long getBytesRead ()
{
return this.m_nTotal;
}
/**
* Returns the number of bytes, which are currently available, without
* blocking.
*
* @throws IOException
* An I/O error occurs.
* @return Number of bytes in the buffer.
*/
@Override
public int available () throws IOException
{
if (this.m_nPos == -1)
return MultipartStream.this.m_nTail - MultipartStream.this.m_nHead - this.m_nPad;
return this.m_nPos - MultipartStream.this.m_nHead;
}
/**
* Offset when converting negative bytes to integers.
*/
private static final int BYTE_POSITIVE_OFFSET = 256;
/**
* Returns the next byte in the stream.
*
* @return The next byte in the stream, as a non-negative integer, or -1 for
* EOF.
* @throws IOException
* An I/O error occurred.
*/
@Override
public int read () throws IOException
{
if (this.m_bClosed)
throw new IFileItemStream.ItemSkippedException ();
if (available () == 0)
if (_makeAvailable () == 0)
return -1;
++this.m_nTotal;
final int b = MultipartStream.this.m_aBuffer[MultipartStream.this.m_nHead++];
if (b >= 0)
return b;
return b + BYTE_POSITIVE_OFFSET;
}
/**
* Reads bytes into the given buffer.
*
* @param b
* The destination buffer, where to write to.
* @param off
* Offset of the first byte in the buffer.
* @param len
* Maximum number of bytes to read.
* @return Number of bytes, which have been actually read, or -1 for EOF.
* @throws IOException
* An I/O error occurred.
*/
@Override
public int read (final byte [] b, final int off, final int len) throws IOException
{
if (this.m_bClosed)
throw new IFileItemStream.ItemSkippedException ();
if (len == 0)
return 0;
int res = available ();
if (res == 0)
{
res = _makeAvailable ();
if (res == 0)
return -1;
}
res = Math.min (res, len);
System.arraycopy (MultipartStream.this.m_aBuffer, MultipartStream.this.m_nHead, b, off, res);
MultipartStream.this.m_nHead += res;
this.m_nTotal += res;
return res;
}
/**
* Closes the input stream.
*
* @throws IOException
* An I/O error occurred.
*/
@Override
public void close () throws IOException
{
close (false);
}
/**
* Closes the input stream.
*
* @param pCloseUnderlying
* Whether to close the underlying stream (hard close)
* @throws IOException
* An I/O error occurred.
*/
@SuppressFBWarnings ("SR_NOT_CHECKED")
public void close (final boolean pCloseUnderlying) throws IOException
{
if (this.m_bClosed)
return;
if (pCloseUnderlying)
{
this.m_bClosed = true;
MultipartStream.this.m_aInput.close ();
}
else
{
while (true)
{
int av = available ();
if (av == 0)
{
av = _makeAvailable ();
if (av == 0)
break;
}
skip (av);
}
}
this.m_bClosed = true;
}
/**
* Skips the given number of bytes.
*
* @param bytes
* Number of bytes to skip.
* @return The number of bytes, which have actually been skipped.
* @throws IOException
* An I/O error occurred.
*/
@Override
public long skip (final long bytes) throws IOException
{
if (this.m_bClosed)
throw new IFileItemStream.ItemSkippedException ();
int av = available ();
if (av == 0)
{
av = _makeAvailable ();
if (av == 0)
return 0;
}
final long res = Math.min (av, bytes);
MultipartStream.this.m_nHead += res;
return res;
}
/**
* Attempts to read more data.
*
* @return Number of available bytes
* @throws IOException
* An I/O error occurred.
*/
private int _makeAvailable () throws IOException
{
if (this.m_nPos != -1)
return 0;
// Move the data to the beginning of the buffer.
this.m_nTotal += MultipartStream.this.m_nTail - MultipartStream.this.m_nHead - this.m_nPad;
System.arraycopy (MultipartStream.this.m_aBuffer,
MultipartStream.this.m_nTail - this.m_nPad,
MultipartStream.this.m_aBuffer,
0,
this.m_nPad);
// Refill buffer with new data.
MultipartStream.this.m_nHead = 0;
MultipartStream.this.m_nTail = this.m_nPad;
while (true)
{
final int nBytesRead = MultipartStream.this.m_aInput.read (MultipartStream.this.m_aBuffer,
MultipartStream.this.m_nTail,
MultipartStream.this.m_nBufSize -
MultipartStream.this.m_nTail);
if (nBytesRead == -1)
{
// The last pad amount is left in the buffer.
// Boundary can't be in there so signal an error
// condition.
throw new MalformedStreamException ("Stream ended unexpectedly");
}
if (MultipartStream.this.m_aNotifier != null)
{
MultipartStream.this.m_aNotifier.noteBytesRead (nBytesRead);
}
MultipartStream.this.m_nTail += nBytesRead;
_findSeparator ();
final int av = available ();
if (av > 0 || this.m_nPos != -1)
return av;
}
}
/**
* Returns, whether the stream is closed.
*
* @return True, if the stream is closed, otherwise false.
*/
@Override
public boolean isClosed ()
{
return this.m_bClosed;
}
}
}