org.odftoolkit.odfdom.pkg.StreamHelper Maven / Gradle / Ivy
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package org.odftoolkit.odfdom.pkg;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* This class reads from an InputStream and writes to an OutputStream.
* No streams will be closed - calling classes must do this.
*/
class StreamHelper {
// 4096 is thought to be the minimum page size for most systems;
// change this for optimization
public static final int PAGE_SIZE = 4096;
private InputStream in;
private OutputStream out;
private boolean mStreamed;
/**
* Read from the input stream and write to the output. This method
* does not close any stream; calling methods must take care of that.
* @throws IOException when io error happens
*/
static void transformStream(InputStream in, OutputStream out) throws IOException {
StreamHelper s = new StreamHelper(in, out);
s.stream();
}
/**
* Create a new StreamHelper
* @param in the input stream used for reading
* @param out the output stream written to
*/
StreamHelper(InputStream in, OutputStream out) {
this.in = in;
this.out = out;
mStreamed = false;
}
/**
* Read from the input stream and write to the output. This method can only
* be called once. A second call will result in an IOException. This method
* does not close any stream; calling methods must take care of that.
* @throws IOException when io error happens
*/
void stream() throws IOException {
if (mStreamed) throw new IOException();
byte[] buf = new byte[PAGE_SIZE];
int r = 0;
// let npe happen if one of the streams is null
while ((r = in.read(buf, 0, PAGE_SIZE)) > -1) {
out.write(buf, 0, r);
}
// free the references
in = null;
out = null;
mStreamed = true;
}
}