package be.nikiroo.utils.streams; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; /** * A simple {@link OutputStream} that is buffered with a bytes array. *
* It is mostly intended to be used as a base class to create new * {@link OutputStream}s with special operation modes, and to give some default * methods. * * @author niki */ public class BufferedOutputStream extends OutputStream { /** The current position in the buffer. */ protected int start; /** The index of the last usable position of the buffer. */ protected int stop; /** The buffer itself. */ protected byte[] buffer; /** An End-Of-File (or buffer, here) marker. */ protected boolean eof; /** The actual under-laying stream. */ protected OutputStream out; /** The number of bytes written to the under-laying stream. */ protected long bytesWritten; /** * Can bypass the flush process for big writes (will directly write to the * under-laying buffer if the array to write is > the internal buffer * size). *
* By default, this is true. */ protected boolean bypassFlush = true; private boolean closed; private int openCounter; private byte[] b1; /** * Create a new {@link BufferedInputStream} that wraps the given * {@link InputStream}. * * @param out * the {@link OutputStream} to wrap */ public BufferedOutputStream(OutputStream out) { this.out = out; this.buffer = new byte[4096]; this.b1 = new byte[1]; this.start = 0; this.stop = 0; } @Override public void write(int b) throws IOException { b1[0] = (byte) b; write(b1, 0, 1); } @Override public void write(byte[] b) throws IOException { write(b, 0, b.length); } @Override public void write(byte[] source, int sourceOffset, int sourceLength) throws IOException { checkClose(); if (source == null) { throw new NullPointerException(); } else if ((sourceOffset < 0) || (sourceOffset > source.length) || (sourceLength < 0) || ((sourceOffset + sourceLength) > source.length) || ((sourceOffset + sourceLength) < 0)) { throw new IndexOutOfBoundsException(); } else if (sourceLength == 0) { return; } if (bypassFlush && sourceLength >= buffer.length) { /* * If the request length exceeds the size of the output buffer, * flush the output buffer and then write the data directly. In this * way buffered streams will cascade harmlessly. */ flush(false); out.write(source, sourceOffset, sourceLength); bytesWritten += (sourceLength - sourceOffset); return; } int done = 0; while (done < sourceLength) { if (available() <= 0) { flush(false); } int now = Math.min(sourceLength - done, available()); System.arraycopy(source, sourceOffset + done, buffer, stop, now); stop += now; done += now; } } /** * The available space in the buffer. * * @return the space in bytes */ private int available() { if (closed) { return 0; } return Math.max(0, buffer.length - stop - 1); } /** * The number of bytes written to the under-laying {@link OutputStream}. * * @return the number of bytes */ public long getBytesWritten() { return bytesWritten; } /** * Return this very same {@link BufferedInputStream}, but keep a counter of * how many streams were open this way. When calling * {@link BufferedInputStream#close()}, decrease this counter if it is not * already zero instead of actually closing the stream. *
* You are now responsible for it — you must close it. *
* This method allows you to use a wrapping stream around this one and still * close the wrapping stream. * * @return the same stream, but you are now responsible for closing it * * @throws IOException * in case of I/O error or if the stream is closed */ public synchronized OutputStream open() throws IOException { checkClose(); openCounter++; return this; } /** * Check that the stream was not closed, and throw an {@link IOException} if * it was. * * @throws IOException * if it was closed */ protected void checkClose() throws IOException { if (closed) { throw new IOException( "This BufferedInputStream was closed, you cannot use it anymore."); } } @Override public void flush() throws IOException { flush(true); } /** * Flush the {@link BufferedOutputStream}, write the current buffered data * to (and optionally also flush) the under-laying stream. *
* If {@link BufferedOutputStream#bypassFlush} is false, all writes to the * under-laying stream are done in this method. *
* This can be used if you want to write some data in the under-laying * stream yourself (in that case, flush this {@link BufferedOutputStream} * with or without flushing the under-laying stream, then you can write to * the under-laying stream). * * @param includingSubStream * also flush the under-laying stream * @throws IOException * in case of I/O error */ public void flush(boolean includingSubStream) throws IOException { if (stop > start) { out.write(buffer, start, stop - start); bytesWritten += (stop - start); } start = 0; stop = 0; if (includingSubStream) { out.flush(); } } /** * Closes this stream and releases any system resources associated with the * stream. *
* Including the under-laying {@link InputStream}. *
* Note: if you called the {@link BufferedInputStream#open()} method * prior to this one, it will just decrease the internal count of how many * open streams it held and do nothing else. The stream will actually be * closed when you have called {@link BufferedInputStream#close()} once more * than {@link BufferedInputStream#open()}. * * @exception IOException * in case of I/O error */ @Override public synchronized void close() throws IOException { close(true); } /** * Closes this stream and releases any system resources associated with the * stream. *
* Including the under-laying {@link InputStream} if * incudingSubStream is true. *
* You can call this method multiple times, it will not cause an * {@link IOException} for subsequent calls. *
* Note: if you called the {@link BufferedInputStream#open()} method * prior to this one, it will just decrease the internal count of how many * open streams it held and do nothing else. The stream will actually be * closed when you have called {@link BufferedInputStream#close()} once more * than {@link BufferedInputStream#open()}. * * @param includingSubStream * also close the under-laying stream * * @exception IOException * in case of I/O error */ public synchronized void close(boolean includingSubStream) throws IOException { if (!closed) { if (openCounter > 0) { openCounter--; } else { closed = true; flush(includingSubStream); if (includingSubStream && out != null) { out.close(); } } } } }