[cp-patches] FYI: ChannelReader

[Robert Schuster]

Hi
Code is unchanged but fixed block comments.

cu
Robert

Michael Koch wrote:

On Fri, Feb 18, 2005 at 03:43:33AM +0100, Robert Schuster wrote:
  

Hi.
I think I have fixed the remaining bits in the ChannelReader. This patch 
adds support for the two missing constructors in 
java.io.InputStreamReader and implements both variants of 
java.nio.newChannel correctly (not being stubs anymore).

2005-02-18  Robert Schuster  <address@hidden>

       * java/nio/channels/Channels: Added FIXMEs about
       stub method implementation.
       (newReader): Implemented.
       * java/io/InputStreamReader:
       (InputStreamReader(InputStream, Charset)): Implemented.
       (InputStreamReader(InputStream, CharsetDecoder)): Implemented.
       * gnu/java/nio/ChannelReader: New class.

If no one objects I want to have this in for 0.14
    

Can you please use "//" for inline comments and not "/* ... */".
This is afaik much easier to read.


Michael


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Index: java/io/InputStreamReader.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/io/InputStreamReader.java,v
retrieving revision 1.18
diff -u -r1.18 InputStreamReader.java
--- java/io/InputStreamReader.java      16 Feb 2005 11:18:37 -0000      1.18
+++ java/io/InputStreamReader.java      18 Feb 2005 02:32:14 -0000
@@ -38,8 +38,11 @@
 
 package java.io;
 
+import java.nio.channels.Channels;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+
 import gnu.java.io.EncodingManager;
-import gnu.java.io.decode.Decoder;
 
 /**
  * This class reads characters from a byte input stream.   The characters
@@ -92,7 +95,7 @@
    * This is the byte-character decoder class that does the reading and
    * translation of bytes from the underlying stream.
    */
-  private Decoder in;
+  private Reader in;
 
   /**
    * This method initializes a new instance of <code>InputStreamReader</code>
@@ -130,6 +133,29 @@
   }
 
   /**
+   * Creates an InputStreamReader that uses a decoder of the given
+   * charset to decode the bytes in the InputStream into
+   * characters.
+   */
+  public InputStreamReader(InputStream in, Charset charset) {
+    /* FIXME: InputStream is wrapped in Channel which is read by a
+     * Reader-implementation for channels. However to fix this we
+     * need to completely move to NIO-style character
+     * encoding/decoding.
+     */
+    this.in = Channels.newReader(Channels.newChannel(in), 
charset.newDecoder(), -1);
+  }
+
+  /**
+   * Creates an InputStreamReader that uses the given charset decoder
+   * to decode the bytes in the InputStream into characters.
+   */
+  public InputStreamReader(InputStream in, CharsetDecoder decoder) {
+    // FIXME: see address@hidden InputStreamReader(InputStream, Charset)
+    this.in = Channels.newReader(Channels.newChannel(in), decoder, -1);
+  }
+  
+  /**
    * This method closes this stream, as well as the underlying 
    * <code>InputStream</code>.
    *
Index: java/nio/channels/Channels.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/nio/channels/Channels.java,v
retrieving revision 1.10
diff -u -r1.10 Channels.java
--- java/nio/channels/Channels.java     12 Jan 2005 10:08:13 -0000      1.10
+++ java/nio/channels/Channels.java     18 Feb 2005 02:32:15 -0000
@@ -38,6 +38,7 @@
 
 package java.nio.channels;
 
+import gnu.java.nio.ChannelReader;
 import gnu.java.nio.InputStreamChannel;
 import gnu.java.nio.OutputStreamChannel;
 
@@ -102,7 +103,7 @@
   public static Reader newReader(ReadableByteChannel ch, CharsetDecoder dec,
                                  int minBufferCap)
   {
-    throw new Error("not implemented");
+    return new ChannelReader(ch, dec, minBufferCap);
   }
 
   /**
@@ -124,6 +125,7 @@
   public static Writer newWriter(WritableByteChannel ch, CharsetEncoder enc,
                                  int minBufferCap)
   {
+    // FIXME: implement 
java.nio.channels.Channel.newWriter(WritableByteChannel, CharsetEncoder, int) 
     throw new Error("not implemented");
   }
 
Index: gnu/java/nio/ChannelReader.java
===================================================================
RCS file: gnu/java/nio/ChannelReader.java
diff -N gnu/java/nio/ChannelReader.java
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ gnu/java/nio/ChannelReader.java     18 Feb 2005 02:32:15 -0000
@@ -0,0 +1,239 @@
+/* ChannelReader.java -- 
+ Copyright (C) 2005 Free Software Foundation, Inc.
+
+ This file is part of GNU Classpath.
+
+ GNU Classpath 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 2, or (at your option)
+ any later version.
+
+ GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA.
+
+ Linking this library statically or dynamically with other modules is
+ making a combined work based on this library.  Thus, the terms and
+ conditions of the GNU General Public License cover the whole
+ combination.
+
+ As a special exception, the copyright holders of this library give you
+ permission to link this library with independent modules to produce an
+ executable, regardless of the license terms of these independent
+ modules, and to copy and distribute the resulting executable under
+ terms of your choice, provided that you also meet, for each linked
+ independent module, the terms and conditions of the license of that
+ module.  An independent module is a module which is not derived from
+ or based on this library.  If you modify this library, you may extend
+ this exception to your version of the library, but you are not
+ obligated to do so.  If you do not wish to do so, delete this
+ exception statement from your version. */
+
+
+package gnu.java.nio;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.channels.ReadableByteChannel;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.CodingErrorAction;
+
+/**
+ * A Reader implementation that works using a ReadableByteChannel and a
+ * CharsetDecoder.
+ * 
+ * <p>
+ * This is a bridge between NIO <->IO character decoding.
+ * </p>
+ * 
+ * @author Robert Schuster
+ */
+public class ChannelReader extends Reader
+{
+
+  private static final int DEFAULT_BUFFER_CAP = 8192;
+
+  private ReadableByteChannel channel;
+
+  private CharsetDecoder decoder;
+
+  private ByteBuffer byteBuffer;
+
+  private CharBuffer charBuffer;
+
+  public ChannelReader(ReadableByteChannel channel, CharsetDecoder decoder,
+                       int minBufferCap)
+  {
+    this.channel = channel;
+    this.decoder = decoder;
+
+    // JDK reports errors, so we do the same.
+    decoder.onMalformedInput(CodingErrorAction.REPORT);
+    decoder.onUnmappableCharacter(CodingErrorAction.REPORT);
+    decoder.reset();
+
+    int size = (minBufferCap == -1) ? DEFAULT_BUFFER_CAP : minBufferCap;
+
+    /*
+     * Allocates the buffers and prepares them for reading, because that is the
+     * first operation being done on them.
+     */
+    byteBuffer = ByteBuffer.allocate(size);
+    byteBuffer.flip();
+    charBuffer = CharBuffer.allocate((int) (size * 
decoder.averageCharsPerByte()));
+  }
+
+  public int read(char[] buf, int offset, int count) throws IOException
+  {
+    /*
+     * I declared channel being null meaning that the reader is closed.
+     */
+    if (!channel.isOpen())
+      throw new IOException("Reader was already closed.");
+
+    /*
+     * I declared decoder being null meaning that there is no more data to read
+     * and convert.
+     */
+    if (decoder == null)
+      return -1;
+
+    /*
+     * Stores the amount of character being read. It -1 so that if no 
conversion
+     * occured the caller will see this as an 'end of file'.
+     */
+    int sum = -1;
+
+    /*
+     * Copies any characters which may be left from the last invocation into 
the
+     * destination array.
+     */
+    if (charBuffer.remaining() > 0)
+      {
+        sum = Math.min(count, charBuffer.remaining());
+        charBuffer.get(buf, offset, sum);
+
+        /*
+         * Updates the control variables according to the latest copy 
operation.
+         */
+        offset += sum;
+        count -= sum;
+      }
+
+    /*
+     * Copies the character which have not been put in the destination array to
+     * the beginning. If data is actually copied count will be 0. If no data is
+     * copied count is >0 and we can now convert some more characters.
+     */
+    charBuffer.compact();
+
+    int converted = 0;
+    boolean last = false;
+
+    while (count != 0)
+      {
+        /*
+         * Tries to convert some bytes (Which will intentionally fail in the
+         * first place because we have not read any bytes yet.)
+         */
+        CoderResult result = decoder.decode(byteBuffer, charBuffer, last);
+        if(result.isMalformed() || result.isUnmappable()) {
+            /* JDK throws exception when bytes are malformed for sure.
+             * FIXME: Unsure what happens when a character is simply
+             * unmappable.
+             */
+            result.throwException();   
+        }
+
+        /*
+         * Marks that we should end this loop regardless whether the caller
+         * wants more chars or not, when this was the last conversion.
+         */
+        if (last)
+          {
+            decoder = null;
+          }
+        else if (result.isUnderflow())
+          {
+            // We need more bytes to do the conversion.
+
+            /*
+             * Copies the not yet converted bytes to the beginning making it
+             * being able to receive more bytes.
+             */
+            byteBuffer.compact();
+
+            // Reads in another bunch of bytes for being converted.
+            if (channel.read(byteBuffer) == -1)
+              {
+                /*
+                 * If there is no more data available in the channel we mark
+                 * that state for the final character conversion run which is
+                 * done in the next loop iteration.
+                 */
+                last = true;
+              }
+
+            // Prepares the byteBuffer for the next character conversion run.
+            byteBuffer.flip();
+          }
+
+        // Prepares the charBuffer for being drained.
+        charBuffer.flip();
+
+        converted = Math.min(count, charBuffer.remaining());
+        charBuffer.get(buf, offset, converted);
+
+        /*
+         * Copies characters which have not yet being copied into the 
char-Array
+         * to the beginning making it possible to read them later (If data is
+         * really copied here, then the caller has received enough characters 
so
+         * far.).
+         */
+        charBuffer.compact();
+
+        /*
+         * Updates the control variables according to the latest copy 
operation.
+         */
+        offset += converted;
+        count -= converted;
+
+        // Updates the amount of transferred characters
+        sum += converted;
+
+        if (decoder == null)
+          {
+            break;
+          }
+
+        /*
+         * Now that more characters have been transfered we let the loop decide
+         * what to do next.
+         */
+      }
+
+    // Makes the charBuffer ready for reading on the next invocation.
+    charBuffer.flip();
+
+    return sum;
+  }
+
+  public void close() throws IOException
+  {
+    channel.close();
+
+    // Makes sure all intermediate data is released by the decoder.
+    if (decoder != null)
+      decoder.reset();
+  }
+
+}
Index: java/io/InputStreamReader.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/io/InputStreamReader.java,v
retrieving revision 1.18
diff -u -r1.18 InputStreamReader.java
--- java/io/InputStreamReader.java      16 Feb 2005 11:18:37 -0000      1.18
+++ java/io/InputStreamReader.java      21 Feb 2005 18:02:59 -0000
@@ -38,8 +38,11 @@
 
 package java.io;
 
+import java.nio.channels.Channels;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+
 import gnu.java.io.EncodingManager;
-import gnu.java.io.decode.Decoder;
 
 /**
  * This class reads characters from a byte input stream.   The characters
@@ -92,7 +95,7 @@
    * This is the byte-character decoder class that does the reading and
    * translation of bytes from the underlying stream.
    */
-  private Decoder in;
+  private Reader in;
 
   /**
    * This method initializes a new instance of <code>InputStreamReader</code>
@@ -130,6 +133,29 @@
   }
 
   /**
+   * Creates an InputStreamReader that uses a decoder of the given
+   * charset to decode the bytes in the InputStream into
+   * characters.
+   */
+  public InputStreamReader(InputStream in, Charset charset) {
+    /* FIXME: InputStream is wrapped in Channel which is read by a
+     * Reader-implementation for channels. However to fix this we
+     * need to completely move to NIO-style character
+     * encoding/decoding.
+     */
+    this.in = Channels.newReader(Channels.newChannel(in), 
charset.newDecoder(), -1);
+  }
+
+  /**
+   * Creates an InputStreamReader that uses the given charset decoder
+   * to decode the bytes in the InputStream into characters.
+   */
+  public InputStreamReader(InputStream in, CharsetDecoder decoder) {
+    // FIXME: see address@hidden InputStreamReader(InputStream, Charset)
+    this.in = Channels.newReader(Channels.newChannel(in), decoder, -1);
+  }
+  
+  /**
    * This method closes this stream, as well as the underlying 
    * <code>InputStream</code>.
    *
Index: java/nio/channels/Channels.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/nio/channels/Channels.java,v
retrieving revision 1.10
diff -u -r1.10 Channels.java
--- java/nio/channels/Channels.java     12 Jan 2005 10:08:13 -0000      1.10
+++ java/nio/channels/Channels.java     21 Feb 2005 18:02:59 -0000
@@ -38,6 +38,7 @@
 
 package java.nio.channels;
 
+import gnu.java.nio.ChannelReader;
 import gnu.java.nio.InputStreamChannel;
 import gnu.java.nio.OutputStreamChannel;
 
@@ -102,7 +103,7 @@
   public static Reader newReader(ReadableByteChannel ch, CharsetDecoder dec,
                                  int minBufferCap)
   {
-    throw new Error("not implemented");
+    return new ChannelReader(ch, dec, minBufferCap);
   }
 
   /**
@@ -124,6 +125,7 @@
   public static Writer newWriter(WritableByteChannel ch, CharsetEncoder enc,
                                  int minBufferCap)
   {
+    // FIXME: implement 
java.nio.channels.Channel.newWriter(WritableByteChannel, CharsetEncoder, int) 
     throw new Error("not implemented");
   }
 
Index: gnu/java/nio/ChannelReader.java
===================================================================
RCS file: gnu/java/nio/ChannelReader.java
diff -N gnu/java/nio/ChannelReader.java
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ gnu/java/nio/ChannelReader.java     21 Feb 2005 18:03:00 -0000
@@ -0,0 +1,239 @@
+/* ChannelReader.java -- 
+ Copyright (C) 2005 Free Software Foundation, Inc.
+
+ This file is part of GNU Classpath.
+
+ GNU Classpath 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 2, or (at your option)
+ any later version.
+
+ GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA.
+
+ Linking this library statically or dynamically with other modules is
+ making a combined work based on this library.  Thus, the terms and
+ conditions of the GNU General Public License cover the whole
+ combination.
+
+ As a special exception, the copyright holders of this library give you
+ permission to link this library with independent modules to produce an
+ executable, regardless of the license terms of these independent
+ modules, and to copy and distribute the resulting executable under
+ terms of your choice, provided that you also meet, for each linked
+ independent module, the terms and conditions of the license of that
+ module.  An independent module is a module which is not derived from
+ or based on this library.  If you modify this library, you may extend
+ this exception to your version of the library, but you are not
+ obligated to do so.  If you do not wish to do so, delete this
+ exception statement from your version. */
+
+
+package gnu.java.nio;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.channels.ReadableByteChannel;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.CodingErrorAction;
+
+/**
+ * A Reader implementation that works using a ReadableByteChannel and a
+ * CharsetDecoder.
+ * 
+ * <p>
+ * This is a bridge between NIO <->IO character decoding.
+ * </p>
+ * 
+ * @author Robert Schuster
+ */
+public class ChannelReader extends Reader
+{
+
+  private static final int DEFAULT_BUFFER_CAP = 8192;
+
+  private ReadableByteChannel channel;
+
+  private CharsetDecoder decoder;
+
+  private ByteBuffer byteBuffer;
+
+  private CharBuffer charBuffer;
+
+  public ChannelReader(ReadableByteChannel channel, CharsetDecoder decoder,
+                       int minBufferCap)
+  {
+    this.channel = channel;
+    this.decoder = decoder;
+
+    // JDK reports errors, so we do the same.
+    decoder.onMalformedInput(CodingErrorAction.REPORT);
+    decoder.onUnmappableCharacter(CodingErrorAction.REPORT);
+    decoder.reset();
+
+    int size = (minBufferCap == -1) ? DEFAULT_BUFFER_CAP : minBufferCap;
+
+    /*
+     * Allocates the buffers and prepares them for reading, because that is the
+     * first operation being done on them.
+     */
+    byteBuffer = ByteBuffer.allocate(size);
+    byteBuffer.flip();
+    charBuffer = CharBuffer.allocate((int) (size * 
decoder.averageCharsPerByte()));
+  }
+
+  public int read(char[] buf, int offset, int count) throws IOException
+  {
+    /*
+     * I declared channel being null meaning that the reader is closed.
+     */
+    if (!channel.isOpen())
+      throw new IOException("Reader was already closed.");
+
+    /*
+     * I declared decoder being null meaning that there is no more data to read
+     * and convert.
+     */
+    if (decoder == null)
+      return -1;
+
+    /*
+     * Stores the amount of character being read. It -1 so that if no 
conversion
+     * occured the caller will see this as an 'end of file'.
+     */
+    int sum = -1;
+
+    /*
+     * Copies any characters which may be left from the last invocation into 
the
+     * destination array.
+     */
+    if (charBuffer.remaining() > 0)
+      {
+        sum = Math.min(count, charBuffer.remaining());
+        charBuffer.get(buf, offset, sum);
+
+        /*
+         * Updates the control variables according to the latest copy 
operation.
+         */
+        offset += sum;
+        count -= sum;
+      }
+
+    /*
+     * Copies the character which have not been put in the destination array to
+     * the beginning. If data is actually copied count will be 0. If no data is
+     * copied count is >0 and we can now convert some more characters.
+     */
+    charBuffer.compact();
+
+    int converted = 0;
+    boolean last = false;
+
+    while (count != 0)
+      {
+        /*
+         * Tries to convert some bytes (Which will intentionally fail in the
+         * first place because we have not read any bytes yet.)
+         */
+        CoderResult result = decoder.decode(byteBuffer, charBuffer, last);
+        if(result.isMalformed() || result.isUnmappable()) {
+            /* JDK throws exception when bytes are malformed for sure.
+             * FIXME: Unsure what happens when a character is simply
+             * unmappable.
+             */
+            result.throwException();   
+        }
+
+        /*
+         * Marks that we should end this loop regardless whether the caller
+         * wants more chars or not, when this was the last conversion.
+         */
+        if (last)
+          {
+            decoder = null;
+          }
+        else if (result.isUnderflow())
+          {
+            // We need more bytes to do the conversion.
+
+            /*
+             * Copies the not yet converted bytes to the beginning making it
+             * being able to receive more bytes.
+             */
+            byteBuffer.compact();
+
+            // Reads in another bunch of bytes for being converted.
+            if (channel.read(byteBuffer) == -1)
+              {
+                /*
+                 * If there is no more data available in the channel we mark
+                 * that state for the final character conversion run which is
+                 * done in the next loop iteration.
+                 */
+                last = true;
+              }
+
+            // Prepares the byteBuffer for the next character conversion run.
+            byteBuffer.flip();
+          }
+
+        // Prepares the charBuffer for being drained.
+        charBuffer.flip();
+
+        converted = Math.min(count, charBuffer.remaining());
+        charBuffer.get(buf, offset, converted);
+
+        /*
+         * Copies characters which have not yet being copied into the 
char-Array
+         * to the beginning making it possible to read them later (If data is
+         * really copied here, then the caller has received enough characters 
so
+         * far.).
+         */
+        charBuffer.compact();
+
+        /*
+         * Updates the control variables according to the latest copy 
operation.
+         */
+        offset += converted;
+        count -= converted;
+
+        // Updates the amount of transferred characters
+        sum += converted;
+
+        if (decoder == null)
+          {
+            break;
+          }
+
+        /*
+         * Now that more characters have been transfered we let the loop decide
+         * what to do next.
+         */
+      }
+
+    // Makes the charBuffer ready for reading on the next invocation.
+    charBuffer.flip();
+
+    return sum;
+  }
+
+  public void close() throws IOException
+  {
+    channel.close();
+
+    // Makes sure all intermediate data is released by the decoder.
+    if (decoder != null)
+      decoder.reset();
+  }
+
+}