From: Niki Roo <niki@nikiroo.be>
Date: Fri, 26 Apr 2019 21:09:29 +0000 (+0200)
Subject: NextableInputStream: separate base behaviour from nextable
X-Git-Tag: fanfix-swing-0.0.1~21^2~120
X-Git-Url: https://git.nikiroo.be/?a=commitdiff_plain;h=33895a7b06d1a8a7c3555da06b215ab1085ac4df;p=fanfix-swing.git

NextableInputStream: separate base behaviour from nextable
---

diff --git a/src/be/nikiroo/utils/BufferedInputStream.java b/src/be/nikiroo/utils/BufferedInputStream.java
new file mode 100644
index 00000000..4a8a8c39
--- /dev/null
+++ b/src/be/nikiroo/utils/BufferedInputStream.java
@@ -0,0 +1,400 @@
+package be.nikiroo.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+
+/**
+ * A simple {@link InputStream} that is buffered with a bytes array.
+ * <p>
+ * It is mostly intended to be used as a base class to create new
+ * {@link InputStream}s with special operation modes, and to give some default
+ * methods.
+ * 
+ * @author niki
+ */
+public class BufferedInputStream extends InputStream {
+	protected int pos;
+	protected int len;
+	protected byte[] buffer;
+	protected boolean eof;
+
+	private boolean closed;
+	private InputStream in;
+	private int openCounter;
+
+	// special use, prefetched next buffer
+	private byte[] buffer2;
+	private int pos2;
+	private int len2;
+	private byte[] originalBuffer;
+
+	private long bytesRead;
+
+	/**
+	 * Create a new {@link BufferedInputStream} that wraps the given
+	 * {@link InputStream}.
+	 * 
+	 * @param in
+	 *            the {@link InputStream} to wrap
+	 */
+	public BufferedInputStream(InputStream in) {
+		this.in = in;
+
+		this.buffer = new byte[4096];
+		this.originalBuffer = this.buffer;
+		this.pos = 0;
+		this.len = 0;
+	}
+
+	/**
+	 * Create a new {@link BufferedInputStream} that wraps the given bytes array
+	 * as a data source.
+	 * 
+	 * @param in
+	 *            the array to wrap, cannot be NULL
+	 */
+	public BufferedInputStream(byte[] in) {
+		this(in, 0, in.length);
+	}
+
+	/**
+	 * Create a new {@link BufferedInputStream} that wraps the given bytes array
+	 * as a data source.
+	 * 
+	 * @param in
+	 *            the array to wrap, cannot be NULL
+	 * @param offset
+	 *            the offset to start the reading at
+	 * @param length
+	 *            the number of bytes to take into account in the array,
+	 *            starting from the offset
+	 * 
+	 * @throws NullPointerException
+	 *             if the array is NULL
+	 * @throws IndexOutOfBoundsException
+	 *             if the offset and length do not correspond to the given array
+	 */
+	public BufferedInputStream(byte[] in, int offset, int length) {
+		if (in == null) {
+			throw new NullPointerException();
+		} else if (offset < 0 || length < 0 || length > in.length - offset) {
+			throw new IndexOutOfBoundsException();
+		}
+
+		this.in = null;
+
+		this.buffer = in;
+		this.originalBuffer = this.buffer;
+		this.pos = offset;
+		this.len = length;
+	}
+
+	/**
+	 * 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.
+	 * <p>
+	 * You are now responsible for it &mdash; you <b>must</b> close it.
+	 * <p>
+	 * 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 InputStream open() throws IOException {
+		checkClose();
+		openCounter++;
+		return this;
+	}
+
+	// max is buffer.size !
+	public boolean startsWiths(String search) throws IOException {
+		return startsWith(search.getBytes("UTF-8"));
+	}
+
+	// max is buffer.size !
+	public boolean startsWith(byte[] search) throws IOException {
+		if (search.length > originalBuffer.length) {
+			throw new IOException(
+					"This stream does not support searching for more than "
+							+ buffer.length + " bytes");
+		}
+
+		checkClose();
+
+		if (available() < search.length) {
+			preRead();
+		}
+
+		if (available() >= search.length) {
+			// Easy path
+			return startsWith(search, buffer, pos);
+		} else if (!eof) {
+			// Harder path
+			if (buffer2 == null && buffer.length == originalBuffer.length) {
+				buffer2 = Arrays.copyOf(buffer, buffer.length * 2);
+
+				pos2 = buffer.length;
+				len2 = in.read(buffer2, pos2, buffer.length);
+				if (len2 > 0) {
+					bytesRead += len2;
+				}
+
+				// Note: here, len/len2 = INDEX of last good byte
+				len2 += pos2;
+			}
+
+			if (available() + (len2 - pos2) >= search.length) {
+				return startsWith(search, buffer2, pos2);
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * The number of bytes read from the under-laying {@link InputStream}.
+	 * 
+	 * @return the number of bytes
+	 */
+	public long getBytesRead() {
+		return bytesRead;
+	}
+
+	/**
+	 * Check if this stream is totally spent (no more data to read or to
+	 * process).
+	 * <p>
+	 * Note: an empty stream that is still not started will return FALSE, as we
+	 * don't know yet if it is empty.
+	 * 
+	 * @return TRUE if it is
+	 */
+	public boolean eof() {
+		return closed || (len < 0 && !hasMoreData());
+	}
+
+	@Override
+	public int read() throws IOException {
+		checkClose();
+
+		preRead();
+		if (eof) {
+			return -1;
+		}
+
+		return buffer[pos++];
+	}
+
+	@Override
+	public int read(byte[] b) throws IOException {
+		return read(b, 0, b.length);
+	}
+
+	@Override
+	public int read(byte[] b, int boff, int blen) throws IOException {
+		checkClose();
+
+		if (b == null) {
+			throw new NullPointerException();
+		} else if (boff < 0 || blen < 0 || blen > b.length - boff) {
+			throw new IndexOutOfBoundsException();
+		} else if (blen == 0) {
+			return 0;
+		}
+
+		int done = 0;
+		while (hasMoreData() && done < blen) {
+			preRead();
+			if (hasMoreData()) {
+				int now = Math.min(blen, len) - pos;
+				if (now > 0) {
+					System.arraycopy(buffer, pos, b, boff, now);
+					pos += now;
+					done += now;
+				}
+			}
+		}
+
+		return done > 0 ? done : -1;
+	}
+
+	@Override
+	public long skip(long n) throws IOException {
+		if (n <= 0) {
+			return 0;
+		}
+
+		long skipped = 0;
+		while (hasMoreData() && n > 0) {
+			preRead();
+
+			long inBuffer = Math.min(n, available());
+			pos += inBuffer;
+			n -= inBuffer;
+			skipped += inBuffer;
+		}
+
+		return skipped;
+	}
+
+	@Override
+	public int available() {
+		if (closed) {
+			return 0;
+		}
+
+		return Math.max(0, len - pos);
+	}
+
+	/**
+	 * Closes this stream and releases any system resources associated with the
+	 * stream.
+	 * <p>
+	 * Including the under-laying {@link InputStream}.
+	 * <p>
+	 * <b>Note:</b> 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.
+	 * <p>
+	 * Including the under-laying {@link InputStream} if
+	 * <tt>incudingSubStream</tt> is true.
+	 * <p>
+	 * You can call this method multiple times, it will not cause an
+	 * {@link IOException} for subsequent calls.
+	 * <p>
+	 * <b>Note:</b> 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
+	 */
+	public synchronized void close(boolean includingSubStream)
+			throws IOException {
+		if (!closed) {
+			if (openCounter > 0) {
+				openCounter--;
+			} else {
+				closed = true;
+				if (includingSubStream && in != null) {
+					in.close();
+				}
+			}
+		}
+	}
+
+	/**
+	 * Check if we still have some data in the buffer and, if not, fetch some.
+	 * 
+	 * @return TRUE if we fetched some data, FALSE if there are still some in
+	 *         the buffer
+	 * 
+	 * @throws IOException
+	 *             in case of I/O error
+	 */
+	protected boolean preRead() throws IOException {
+		boolean hasRead = false;
+		if (!eof && in != null && pos >= len) {
+			pos = 0;
+			if (buffer2 != null) {
+				buffer = buffer2;
+				pos = pos2;
+				len = len2;
+
+				buffer2 = null;
+				pos2 = 0;
+				len2 = 0;
+			} else {
+				buffer = originalBuffer;
+
+				len = read(in, buffer);
+				if (len > 0) {
+					bytesRead += len;
+				}
+			}
+
+			hasRead = true;
+		}
+
+		if (pos >= len) {
+			eof = true;
+		}
+
+		return hasRead;
+	}
+
+	/**
+	 * Read the under-laying stream into the local buffer.
+	 * 
+	 * @param in
+	 *            the under-laying {@link InputStream}
+	 * @param buffer
+	 *            the buffer we use in this {@link BufferedInputStream}
+	 * 
+	 * @return the number of bytes read
+	 * 
+	 * @throws IOException
+	 *             in case of I/O error
+	 */
+	protected int read(InputStream in, byte[] buffer) throws IOException {
+		return in.read(buffer);
+	}
+
+	/**
+	 * We have more data available in the buffer or we can fetch more.
+	 * 
+	 * @return TRUE if it is the case, FALSE if not
+	 */
+	protected boolean hasMoreData() {
+		return !closed && !(eof && pos >= len);
+	}
+
+	/**
+	 * 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 NextableInputStream was closed, you cannot use it anymore.");
+		}
+	}
+
+	// buffer must be > search
+	static private boolean startsWith(byte[] search, byte[] buffer, int offset) {
+		boolean same = true;
+		for (int i = 0; i < search.length; i++) {
+			if (search[i] != buffer[offset + i]) {
+				same = false;
+				break;
+			}
+		}
+
+		return same;
+	}
+}
diff --git a/src/be/nikiroo/utils/NextableInputStream.java b/src/be/nikiroo/utils/NextableInputStream.java
index d9f27cef..37322c9e 100644
--- a/src/be/nikiroo/utils/NextableInputStream.java
+++ b/src/be/nikiroo/utils/NextableInputStream.java
@@ -2,7 +2,6 @@ package be.nikiroo.utils;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.util.Arrays;
 
 /**
  * This {@link InputStream} can be separated into sub-streams (you can process
@@ -13,26 +12,10 @@ import java.util.Arrays;
  * 
  * @author niki
  */
-public class NextableInputStream extends InputStream {
+public class NextableInputStream extends BufferedInputStream {
 	private NextableInputStreamStep step;
 	private boolean started;
 	private boolean stopped;
-	private boolean closed;
-
-	private InputStream in;
-	private int openCounter;
-	private boolean eof;
-	private int pos;
-	private int len;
-	private byte[] buffer;
-
-	// special use, prefetched next buffer
-	private byte[] buffer2;
-	private int pos2;
-	private int len2;
-	private byte[] originalBuffer;
-
-	private long bytesRead;
 
 	/**
 	 * Create a new {@link NextableInputStream} that wraps the given
@@ -45,13 +28,8 @@ public class NextableInputStream extends InputStream {
 	 *            case it will behave as a normal {@link InputStream})
 	 */
 	public NextableInputStream(InputStream in, NextableInputStreamStep step) {
-		this.in = in;
+		super(in);
 		this.step = step;
-
-		this.buffer = new byte[4096];
-		this.originalBuffer = this.buffer;
-		this.pos = 0;
-		this.len = 0;
 	}
 
 	/**
@@ -90,45 +68,11 @@ public class NextableInputStream extends InputStream {
 	 */
 	public NextableInputStream(byte[] in, NextableInputStreamStep step,
 			int offset, int length) {
-		if (in == null) {
-			throw new NullPointerException();
-		} else if (offset < 0 || length < 0 || length > in.length - offset) {
-			throw new IndexOutOfBoundsException();
-		}
-
-		this.in = null;
+		super(in, offset, length);
 		this.step = step;
-
-		this.buffer = in;
-		this.originalBuffer = this.buffer;
-		this.pos = offset;
-		this.len = length;
-
 		checkBuffer(true);
 	}
 
-	/**
-	 * Return this very same {@link NextableInputStream}, but keep a counter of
-	 * how many streams were open this way. When calling
-	 * {@link NextableInputStream#close()}, decrease this counter if it is not
-	 * already zero instead of actually closing the stream.
-	 * <p>
-	 * You are now responsible for it &mdash; you <b>must</b> close it.
-	 * <p>
-	 * 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 InputStream open() throws IOException {
-		checkClose();
-		openCounter++;
-		return this;
-	}
-
 	/**
 	 * Unblock the processing of the next sub-stream.
 	 * <p>
@@ -167,199 +111,6 @@ public class NextableInputStream extends InputStream {
 		return next(true);
 	}
 
-	// max is buffer.size !
-	public boolean startsWiths(String search) throws IOException {
-		return startsWith(search.getBytes("UTF-8"));
-	}
-
-	// max is buffer.size !
-	public boolean startsWith(byte[] search) throws IOException {
-		if (search.length > originalBuffer.length) {
-			throw new IOException(
-					"This stream does not support searching for more than "
-							+ buffer.length + " bytes");
-		}
-
-		checkClose();
-
-		if (available() < search.length) {
-			preRead();
-		}
-
-		if (available() >= search.length) {
-			// Easy path
-			return startsWith(search, buffer, pos);
-		} else if (!eof) {
-			// Harder path
-			if (buffer2 == null && buffer.length == originalBuffer.length) {
-				buffer2 = Arrays.copyOf(buffer, buffer.length * 2);
-
-				pos2 = buffer.length;
-				len2 = in.read(buffer2, pos2, buffer.length);
-				if (len2 > 0) {
-					bytesRead += len2;
-				}
-
-				// Note: here, len/len2 = INDEX of last good byte
-				len2 += pos2;
-			}
-
-			if (available() + (len2 - pos2) >= search.length) {
-				return startsWith(search, buffer2, pos2);
-			}
-		}
-
-		return false;
-	}
-
-	/**
-	 * The number of bytes read from the under-laying {@link InputStream}.
-	 * 
-	 * @return the number of bytes
-	 */
-	public long getBytesRead() {
-		return bytesRead;
-	}
-
-	/**
-	 * Check if this stream is totally spent (no more data to read or to
-	 * process).
-	 * <p>
-	 * Note: an empty stream that is still not started will return FALSE, as we
-	 * don't know yet if it is empty.
-	 * 
-	 * @return TRUE if it is
-	 */
-	public boolean eof() {
-		return closed || (len < 0 && !hasMoreData());
-	}
-
-	@Override
-	public int read() throws IOException {
-		checkClose();
-
-		preRead();
-		if (eof) {
-			return -1;
-		}
-
-		return buffer[pos++];
-	}
-
-	@Override
-	public int read(byte[] b) throws IOException {
-		return read(b, 0, b.length);
-	}
-
-	@Override
-	public int read(byte[] b, int boff, int blen) throws IOException {
-		checkClose();
-
-		if (b == null) {
-			throw new NullPointerException();
-		} else if (boff < 0 || blen < 0 || blen > b.length - boff) {
-			throw new IndexOutOfBoundsException();
-		} else if (blen == 0) {
-			return 0;
-		}
-
-		int done = 0;
-		while (hasMoreData() && done < blen) {
-			preRead();
-			if (hasMoreData()) {
-				int now = Math.min(blen, len) - pos;
-				if (now > 0) {
-					System.arraycopy(buffer, pos, b, boff, now);
-					pos += now;
-					done += now;
-				}
-			}
-		}
-
-		return done > 0 ? done : -1;
-	}
-
-	@Override
-	public long skip(long n) throws IOException {
-		if (n <= 0) {
-			return 0;
-		}
-
-		long skipped = 0;
-		while (hasMoreData() && n > 0) {
-			preRead();
-
-			long inBuffer = Math.min(n, available());
-			pos += inBuffer;
-			n -= inBuffer;
-			skipped += inBuffer;
-		}
-
-		return skipped;
-	}
-
-	@Override
-	public int available() {
-		if (closed) {
-			return 0;
-		}
-
-		return Math.max(0, len - pos);
-	}
-
-	/**
-	 * Closes this stream and releases any system resources associated with the
-	 * stream.
-	 * <p>
-	 * Including the under-laying {@link InputStream}.
-	 * <p>
-	 * <b>Note:</b> if you called the {@link NextableInputStream#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 NextableInputStream#close()} once more
-	 * than {@link NextableInputStream#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.
-	 * <p>
-	 * Including the under-laying {@link InputStream} if
-	 * <tt>incudingSubStream</tt> is true.
-	 * <p>
-	 * You can call this method multiple times, it will not cause an
-	 * {@link IOException} for subsequent calls.
-	 * <p>
-	 * <b>Note:</b> if you called the {@link NextableInputStream#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 NextableInputStream#close()} once more
-	 * than {@link NextableInputStream#open()}.
-	 * 
-	 * @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;
-				if (includingSubStream && in != null) {
-					in.close();
-				}
-			}
-		}
-	}
-
 	/**
 	 * Check if we still have some data in the buffer and, if not, fetch some.
 	 * 
@@ -369,35 +120,19 @@ public class NextableInputStream extends InputStream {
 	 * @throws IOException
 	 *             in case of I/O error
 	 */
-	private boolean preRead() throws IOException {
-		boolean hasRead = false;
-		if (!eof && in != null && pos >= len && !stopped) {
-			pos = 0;
-			if (buffer2 != null) {
-				buffer = buffer2;
-				pos = pos2;
-				len = len2;
-
-				buffer2 = null;
-				pos2 = 0;
-				len2 = 0;
-			} else {
-				buffer = originalBuffer;
-				len = in.read(buffer);
-				if (len > 0) {
-					bytesRead += len;
-				}
-			}
-
+	@Override
+	protected boolean preRead() throws IOException {
+		if (!stopped) {
+			boolean bufferChanged = super.preRead();
 			checkBuffer(true);
-			hasRead = true;
+			return bufferChanged;
 		}
 
 		if (pos >= len) {
 			eof = true;
 		}
 
-		return hasRead;
+		return false;
 	}
 
 	/**
@@ -405,8 +140,9 @@ public class NextableInputStream extends InputStream {
 	 * 
 	 * @return TRUE if it is the case, FALSE if not
 	 */
-	private boolean hasMoreData() {
-		return !closed && started && !(eof && pos >= len);
+	@Override
+	protected boolean hasMoreData() {
+		return started && super.hasMoreData();
 	}
 
 	/**
@@ -482,31 +218,4 @@ public class NextableInputStream extends InputStream {
 
 		return false;
 	}
-
-	/**
-	 * Check that the stream was not closed, and throw an {@link IOException} if
-	 * it was.
-	 * 
-	 * @throws IOException
-	 *             if it was closed
-	 */
-	private void checkClose() throws IOException {
-		if (closed) {
-			throw new IOException(
-					"This NextableInputStream was closed, you cannot use it anymore.");
-		}
-	}
-
-	// buffer must be > search
-	static private boolean startsWith(byte[] search, byte[] buffer, int offset) {
-		boolean same = true;
-		for (int i = 0; i < search.length; i++) {
-			if (search[i] != buffer[offset + i]) {
-				same = false;
-				break;
-			}
-		}
-
-		return same;
-	}
 }