com.jn.langx.codec.BaseNCodecOutputStream Maven / Gradle / Ivy
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Java lang extensions for java6+, a supplement to , replacement of a Guava, commons-lang.
Core utilities, Collection utilities, IO utilities, Cache, Configuration library ...
package com.jn.langx.codec;
import com.jn.langx.util.Preconditions;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import static com.jn.langx.codec.BaseNCodec.EOF;
/**
* Abstract superclass for Base-N output streams.
*/
public class BaseNCodecOutputStream extends FilterOutputStream {
private final boolean doEncode;
private final BaseNCodec baseNCodec;
private final byte[] singleByte = new byte[1];
private final BaseNCodec.Context context = new BaseNCodec.Context();
public BaseNCodecOutputStream(final OutputStream out, final BaseNCodec basedCodec, final boolean doEncode) {
super(out);
this.baseNCodec = basedCodec;
this.doEncode = doEncode;
}
/**
* Writes the specified byte
to this output stream.
*
* @param i source byte
* @throws IOException if an I/O error occurs.
*/
@Override
public void write(final int i) throws IOException {
singleByte[0] = (byte) i;
write(singleByte, 0, 1);
}
/**
* Writes len
bytes from the specified b
array starting at offset
to this
* output stream.
*
* @param b source byte array
* @param offset where to start reading the bytes
* @param len maximum number of bytes to write
* @throws IOException if an I/O error occurs.
* @throws NullPointerException if the byte array parameter is null
* @throws IndexOutOfBoundsException if offset, len or buffer size are invalid
*/
@Override
public void write(final byte b[], final int offset, final int len) throws IOException {
Preconditions.checkNotNull(b);
if (offset < 0 || len < 0) {
throw new IndexOutOfBoundsException();
} else if (offset > b.length || offset + len > b.length) {
throw new IndexOutOfBoundsException();
} else if (len > 0) {
if (doEncode) {
baseNCodec.encode(b, offset, len, context);
} else {
baseNCodec.decode(b, offset, len, context);
}
flush(false);
}
}
/**
* Flushes this output stream and forces any buffered output bytes to be written out to the stream. If propagate is
* true, the wrapped stream will also be flushed.
*
* @param propagate boolean flag to indicate whether the wrapped OutputStream should also be flushed.
* @throws IOException if an I/O error occurs.
*/
private void flush(final boolean propagate) throws IOException {
final int avail = baseNCodec.available(context);
if (avail > 0) {
final byte[] buf = new byte[avail];
final int c = baseNCodec.readResults(buf, 0, avail, context);
if (c > 0) {
out.write(buf, 0, c);
}
}
if (propagate) {
out.flush();
}
}
/**
* Flushes this output stream and forces any buffered output bytes to be written out to the stream.
*
* @throws IOException if an I/O error occurs.
*/
@Override
public void flush() throws IOException {
flush(true);
}
/**
* Closes this output stream and releases any system resources associated with the stream.
*
* To write the EOF marker without closing the stream, call {@link #eof()} or use an
* Apache Commons IO CloseShieldOutputStream.
*
*
* @throws IOException if an I/O error occurs.
*/
@Override
public void close() throws IOException {
eof();
flush();
out.close();
}
/**
* Writes EOF.
*
* @throws IOException if an I/O error occurs.
*/
public void eof() throws IOException {
// Notify encoder of EOF (-1).
if (doEncode) {
baseNCodec.encode(singleByte, 0, EOF, context);
} else {
baseNCodec.decode(singleByte, 0, EOF, context);
}
}
}