/*******************************************************************************
* This file is part of logisim-evolution.
*
* logisim-evolution is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* logisim-evolution is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with logisim-evolution. If not, see <http://www.gnu.org/licenses/>.
*
* Original code by Carl Burch (http://www.cburch.com), 2011.
* Subsequent modifications by :
* + Haute École Spécialisée Bernoise
* http://www.bfh.ch
* + Haute École du paysage, d'ingénierie et d'architecture de Genève
* http://hepia.hesge.ch/
* + Haute École d'Ingénierie et de Gestion du Canton de Vaud
* http://www.heig-vd.ch/
* The project is currently maintained by :
* + REDS Institute - HEIG-VD
* Yverdon-les-Bains, Switzerland
* http://reds.heig-vd.ch
*******************************************************************************/
package com.cburch.logisim.file;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
/**
* Adapts a <code>Reader</code> as an <code>InputStream</code>. Adapted from
* <CODE>StringInputStream</CODE>.
*
*/
public class ReaderInputStream extends InputStream {
/** Source Reader */
private Reader in;
private String encoding = System.getProperty("file.encoding");
private byte[] slack;
private int begin;
/**
* Construct a <CODE>ReaderInputStream</CODE> for the specified
* <CODE>Reader</CODE>.
*
* @param reader
* <CODE>Reader</CODE>. Must not be <code>null</code>.
*/
public ReaderInputStream(Reader reader) {
in = reader;
}
/**
* Construct a <CODE>ReaderInputStream</CODE> for the specified
* <CODE>Reader</CODE>, with the specified encoding.
*
* @param reader
* non-null <CODE>Reader</CODE>.
* @param encoding
* non-null <CODE>String</CODE> encoding.
*/
public ReaderInputStream(Reader reader, String encoding) {
this(reader);
if (encoding == null) {
throw new IllegalArgumentException("encoding must not be null");
} else {
this.encoding = encoding;
}
}
/**
* @return the current number of bytes ready for reading
* @exception IOException
* if an error occurs
*/
@Override
public synchronized int available() throws IOException {
if (in == null) {
throw new IOException("Stream Closed");
}
if (slack != null) {
return slack.length - begin;
}
if (in.ready()) {
return 1;
} else {
return 0;
}
}
/**
* Closes the Stringreader.
*
* @exception IOException
* if the original StringReader fails to be closed
*/
@Override
public synchronized void close() throws IOException {
if (in != null) {
in.close();
slack = null;
in = null;
}
}
/**
* Marks the read limit of the StringReader.
*
* @param limit
* the maximum limit of bytes that can be read before the mark
* position becomes invalid
*/
@Override
public synchronized void mark(final int limit) {
try {
in.mark(limit);
} catch (IOException ioe) {
throw new RuntimeException(ioe.getMessage());
}
}
/**
* @return false - mark is not supported
*/
@Override
public boolean markSupported() {
return false; // would be imprecise
}
/**
* Reads from the <CODE>Reader</CODE>, returning the same value.
*
* @return the value of the next character in the <CODE>Reader</CODE>.
*
* @exception IOException
* if the original <code>Reader</code> fails to be read
*/
@Override
public synchronized int read() throws IOException {
if (in == null) {
throw new IOException("Stream Closed");
}
byte result;
if (slack != null && begin < slack.length) {
result = slack[begin];
if (++begin == slack.length) {
slack = null;
}
} else {
byte[] buf = new byte[1];
if (read(buf, 0, 1) <= 0) {
result = -1;
}
result = buf[0];
}
if (result < -1) {
result += 256;
}
return result;
}
/**
* Reads from the <code>Reader</code> into a byte array
*
* @param b
* the byte array to read into
* @param off
* the offset in the byte array
* @param len
* the length in the byte array to fill
* @return the actual number read into the byte array, -1 at the end of the
* stream
* @exception IOException
* if an error occurs
*/
@Override
public synchronized int read(byte[] b, int off, int len) throws IOException {
if (in == null) {
throw new IOException("Stream Closed");
}
while (slack == null) {
char[] buf = new char[len]; // might read too much
int n = in.read(buf);
if (n == -1) {
return -1;
}
if (n > 0) {
slack = new String(buf, 0, n).getBytes(encoding);
begin = 0;
}
}
if (len > slack.length - begin) {
len = slack.length - begin;
}
System.arraycopy(slack, begin, b, off, len);
if ((begin += len) >= slack.length) {
slack = null;
}
return len;
}
/**
* Resets the StringReader.
*
* @exception IOException
* if the StringReader fails to be reset
*/
@Override
public synchronized void reset() throws IOException {
if (in == null) {
throw new IOException("Stream Closed");
}
slack = null;
in.reset();
}
}