org.jruby.embed.io.ReaderInputStream Maven / Gradle / Ivy
/**
* **** BEGIN LICENSE BLOCK *****
* Version: EPL 2.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* 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.eclipse.org/legal/epl-v20.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2009-2010 Yoko Harada
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the EPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the EPL, the GPL or the LGPL.
* **** END LICENSE BLOCK *****
*/
package org.jruby.embed.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import java.util.ArrayList;
import java.util.List;
/**
* A ReaderInputStream converts java.io.Reader to java.io.InputStream. The
* ReaderInputStream reads data in a given Reader object into its internal buffer
* so that users of this class can access the file that Reader read by using methods
* defined in java.io.InputStream.
*
* @author Yoko Harada
*/
public class ReaderInputStream extends InputStream {
private static final int DEFAULT_CHAR_BUFFER_SIZE = 8192;
private static final int DEFAULT_BYTE_BUFFER_SIZE = 8192;
private final Reader reader;
private byte[] bytes = null;
private int totalBytes = 0;
private int position = 0;
private int markedIndex = -1;
private int readlimit = 0;
private boolean isOpen = true;
private CharsetEncoder encoder;
private final Object lock = new Object();
/**
* Creates ReaderInputStream from a given Reader type object with a default encoding.
*
* @param reader java.io.Reader object to be read data from.
*/
public ReaderInputStream(Reader reader) {
this(reader, null);
}
/**
* Creates ReaderInputStream from a given Reader type object with a specifed encoding.
*
* @param reader java.io.Reader object to be read data from.
* @param encoding an encoding of the created stream.
*/
public ReaderInputStream(Reader reader, String encoding) {
this.reader = reader;
if (encoding == null) {
if (reader instanceof InputStreamReader) {
encoding = ((InputStreamReader) reader).getEncoding();
} else {
encoding = Charset.defaultCharset().name();
}
} else if (!Charset.isSupported(encoding)) {
throw new IllegalArgumentException(encoding + " is not supported");
}
encoder = Charset.forName(encoding).newEncoder();
encoder.onMalformedInput(CodingErrorAction.REPLACE);
encoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
try {
fillByteBuffer(reader);
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
private void fillByteBuffer(Reader reader) throws IOException {
CharBuffer cbuf = CharBuffer.allocate(DEFAULT_CHAR_BUFFER_SIZE);
ByteBuffer bbuf = ByteBuffer.allocate(DEFAULT_BYTE_BUFFER_SIZE);
List list = new ArrayList();
while (true) {
cbuf.clear();
int size = reader.read(cbuf);
if (size <= 0) {
break;
}
cbuf.limit(cbuf.position());
cbuf.rewind();
boolean eof = false;
while (!eof) {
CoderResult cr = encoder.encode(cbuf, bbuf, eof);
if (cr.isError()) {
cr.throwException();
} else if (cr.isUnderflow()) {
appendBytes(list, bbuf);
eof = true;
} else if (cr.isOverflow()) {
appendBytes(list, bbuf);
bbuf.clear();
}
}
}
getByteArray(list);
}
private void appendBytes(List list, ByteBuffer bb) {
bb.flip();
int length = bb.limit();
totalBytes += length;
byte[] dst = new byte[length];
System.arraycopy(bb.array(), bb.position(), dst, 0, length);
list.add(dst);
}
private void getByteArray(List list) {
bytes = new byte[totalBytes];
int index = 0;
for (byte[] bb : list) {
for (int i=0; i Note that while some implementations of {@code InputStream} will return
* the total number of bytes in the stream, many will not. It is
* never correct to use the return value of this method to allocate
* a buffer intended to hold all data in this stream.
*
* A subclass' implementation of this method may choose to throw an
* {@link IOException} if this input stream has been closed by
* invoking the {@link #close()} method.
*
*
The {@code available} method for class {@code InputStream} always
* returns {@code 0}.
*
* @return an estimate of the number of bytes that can be read (or skipped
* over) from this input stream without blocking or {@code 0} when
* it reaches the end of the input stream.
* @exception IOException if an I/O error occurs.
*/
@Override
public int available() throws IOException {
synchronized (lock) {
confirmOpen();
if (bytes == null) {
throw new IOException("This stream is not available.");
}
return totalBytes - position;
}
}
/**
* Closes this input stream and releases any system resources associated
* with the stream.
*
* @exception IOException if an I/O error occurs.
*/
@Override
public void close() throws IOException {
synchronized (lock) {
confirmOpen();
isOpen = false;
encoder = null;
bytes = null;
//reader.close();
}
}
/**
* Marks the current position in this input stream. A subsequent call to
* the reset method repositions this stream at the last marked
* position so that subsequent reads re-read the same bytes.
*
*
The readlimit arguments tells this input stream to
* allow that many bytes to be read before the mark position gets
* invalidated.
*
*
The general contract of mark is that, if the method
* markSupported returns true, the stream somehow
* remembers all the bytes read after the call to mark and
* stands ready to supply those same bytes again if and whenever the method
* reset is called. However, the stream is not required to
* remember any data at all if more than readlimit bytes are
* read from the stream before reset is called.
*
*
Marking a closed stream should not have any effect on the stream.
*
*
The mark method of InputStream does
* nothing.
*
* @param readlimit the maximum limit of bytes that can be read before
* the mark position becomes invalid.
* @see java.io.InputStream#reset()
*/
@Override
public synchronized void mark(int readlimit) {
if (readlimit < 0) {
throw new IllegalArgumentException("Read limit < 0");
}
synchronized (lock) {
if (isOpen) {
this.readlimit = readlimit;
markedIndex = position;
}
}
}
/**
* Tests if this input stream supports the mark and
* reset methods. Whether or not mark and
* reset are supported is an invariant property of a
* particular input stream instance.
*
* @return true if this stream instance supports the mark
* and reset methods; false otherwise.
* @see java.io.InputStream#mark(int)
* @see java.io.InputStream#reset()
*/
@Override
public boolean markSupported() {
return true;
}
/**
* Reads the next byte of data from the 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 value -1 is returned. This method
* blocks until input data is available, the end of the stream is detected,
* or an exception is thrown.
*
*
A subclass must provide an implementation of this method.
*
* @return the next byte of data, or -1 if the end of the
* stream is reached.
* @exception IOException if an I/O error occurs.
*/
@Override
public int read() throws IOException {
synchronized (lock) {
confirmOpen();
if (position >= totalBytes) {
return -1;
} else {
return bytes[position++];
}
}
}
/**
* Reads some number of bytes from the input stream and stores them into
* the buffer array b. The number of bytes actually read is
* returned as an integer. This method blocks until input data is
* available, end of file is detected, or an exception is thrown.
*
*
If the length of b is zero, then no bytes are read and
* 0 is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at the
* end of the file, the value -1 is returned; otherwise, at
* least one byte is read and stored into b.
*
*
The first byte read is stored into element b[0], the
* next one into b[1], and so on. The number of bytes read is,
* at most, equal to the length of b. Let k be the
* number of bytes actually read; these bytes will be stored in elements
* b[0] through b[k-1],
* leaving elements b[k] through
* b[b.length-1] unaffected.
*
*
The read(b) method for class InputStream
* has the same effect as:
read(b, 0, b.length)
*
* @param b the buffer into which the data is read.
* @return the total number of bytes read into the buffer, or
* -1 is there is no more data because the end of
* the stream has been reached.
* @exception IOException If the first byte cannot be read for any reason
* other than the end of the file, if the input stream has been closed, or
* if some other I/O error occurs.
* @exception NullPointerException if b is null.
* @see java.io.InputStream#read(byte[], int, int)
*/
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Reads up to len bytes of data from the input stream into
* an array of bytes. An attempt is made to read as many as
* len bytes, but a smaller number may be read.
* The number of bytes actually read is returned as an integer.
*
* This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
*
If len is zero, then no bytes are read and
* 0 is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at end of
* file, the value -1 is returned; otherwise, at least one
* byte is read and stored into b.
*
*
The first byte read is stored into element b[off], the
* next one into b[off+1], and so on. The number of bytes read
* is, at most, equal to len. Let k be the number of
* bytes actually read; these bytes will be stored in elements
* b[off] through b[off+k-1],
* leaving elements b[off+k] through
* b[off+len-1] unaffected.
*
*
In every case, elements b[0] through
* b[off] and elements b[off+len] through
* b[b.length-1] are unaffected.
*
*
The read(b, off, len) method
* for class InputStream simply calls the method
* read() repeatedly. If the first such call results in an
* IOException, that exception is returned from the call to
* the read(b, off, len) method. If
* any subsequent call to read() results in a
* IOException, the exception is caught and treated as if it
* were end of file; the bytes read up to that point are stored into
* b and the number of bytes read before the exception
* occurred is returned. The default implementation of this method blocks
* until the requested amount of input data len has been read,
* end of file is detected, or an exception is thrown. Subclasses are encouraged
* to provide a more efficient implementation of this method.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array b
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* -1 if there is no more data because the end of
* the stream has been reached.
* @exception IOException If the first byte cannot be read for any reason
* other than end of file, or if the input stream has been closed, or if
* some other I/O error occurs.
* @exception NullPointerException If b is null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* b.length - off
* @see java.io.InputStream#read()
*/
@Override
public int read(byte[] b, int off, int len) throws IOException {
synchronized (lock) {
confirmOpen();
if (len == 0) {
return 0;
}
if (position >= totalBytes) {
return -1;
}
if (off < 0 || off > totalBytes || len < 0) {
throw new IllegalArgumentException("Either one of, or both of off and len are invalid.");
}
int start = position + off;
start = start < totalBytes ? start : totalBytes - 1;
int end = start + len;
end = end < totalBytes ? end : totalBytes - 1;
int actuallyRead = Math.min((end - start) + 1, len);
System.arraycopy(bytes, start, b, 0, actuallyRead);
position += actuallyRead;
return actuallyRead;
}
}
/**
* Repositions this stream to the position at the time the
* mark method was last called on this input stream.
*
*
The general contract of reset is:
*
*
*
* - If the method
markSupported returns
* true, then:
*
* - If the method
mark has not been called since
* the stream was created, or the number of bytes read from the stream
* since mark was last called is larger than the argument
* to mark at that last call, then an
* IOException might be thrown.
*
* - If such an
IOException is not thrown, then the
* stream is reset to a state such that all the bytes read since the
* most recent call to mark (or since the start of the
* file, if mark has not been called) will be resupplied
* to subsequent callers of the read method, followed by
* any bytes that otherwise would have been the next input data as of
* the time of the call to reset.
*
* - If the method
markSupported returns
* false, then:
*
* - The call to
reset may throw an
* IOException.
*
* - If an
IOException is not thrown, then the stream
* is reset to a fixed state that depends on the particular type of the
* input stream and how it was created. The bytes that will be supplied
* to subsequent callers of the read method depend on the
* particular type of the input stream.
*
* @exception IOException if this stream has not been marked or if the
* mark has been invalidated.
* @see java.io.InputStream#mark(int)
* @see java.io.IOException
*/
@Override
public synchronized void reset() throws IOException {
synchronized (lock) {
if (!isOpen) {
throw new IOException("This stream has been closed.");
}
if (markedIndex < 0) {
throw new IOException("This stream is not marked.");
}
if ((position - markedIndex) > readlimit) {
throw new IOException("Mark is invalidated.");
}
position = markedIndex;
}
}
/**
* Skips over and discards n bytes of data from this input
* stream. The skip method may, for a variety of reasons, end
* up skipping over some smaller number of bytes, possibly 0.
* This may result from any of a number of conditions; reaching end of file
* before n bytes have been skipped is only one possibility.
* The actual number of bytes skipped is returned. If n is
* negative, no bytes are skipped.
*
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException if the stream does not support seek,
* or if some other I/O error occurs.
*/
@Override
public long skip(long n) throws IOException {
if (n < 0L) {
throw new IllegalArgumentException("Negarive skip");
}
synchronized (lock) {
if (!isOpen) {
throw new IOException("This stream has been closed.");
}
long skipped;
if ((totalBytes - position) < n) {
skipped = totalBytes - position;
position = totalBytes;
} else {
skipped = n;
position += n;
}
return skipped;
}
}
}