--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/com/go/trove/io/InternedCharToByteBuffer.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,258 @@
+/* ====================================================================
+ * Trove - Copyright (c) 1999-2000 Walt Disney Internet Group
+ * ====================================================================
+ * The Tea Software License, Version 1.1
+ *
+ * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution,
+ *    if any, must include the following acknowledgment:
+ *       "This product includes software developed by the
+ *        Walt Disney Internet Group (http://opensource.go.com/)."
+ *    Alternately, this acknowledgment may appear in the software itself,
+ *    if and wherever such third-party acknowledgments normally appear.
+ *
+ * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must
+ *    not be used to endorse or promote products derived from this
+ *    software without prior written permission. For written
+ *    permission, please contact opensource@dig.com.
+ *
+ * 5. Products derived from this software may not be called "Tea",
+ *    "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet",
+ *    "Kettle", "Trove" or "BeanDoc" appear in their name, without prior
+ *    written permission of the Walt Disney Internet Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * For more information about Tea, please see http://opensource.go.com/.
+ */
+
+package com.go.trove.io;
+
+import java.io.*;
+import java.util.*;
+import com.go.trove.util.IdentityMap;
+
+/******************************************************************************
+ * A CharToByteBuffer that keeps track of interned strings (mainly string
+ * literals) and statically caches the results of those strings after applying
+ * a byte conversion. This can improve performance if many of the strings being
+ * passed to the append method have been converted before.
+ *
+ * @author Brian S O'Neill
+ * @version
+ * <!--$$Revision: 1.1 $-->, <!--$$JustDate:-->  7/31/01 <!-- $-->
+ */
+public class InternedCharToByteBuffer
+    implements CharToByteBuffer, Serializable
+{
+    private static final int CACHES_PER_ENCODING = 11;
+    private static final int MIN_LENGTH = 4;
+
+    private static final Object MARKER = new Object();
+
+    private static Map cEncodings = new HashMap(7);
+
+    private static Random cLastRandom = new Random();
+
+    /**
+     * Returns several caches for the given encoding. A character in the
+     * string key is used to select the correct cache. By breaking up the
+     * cache in this way, the synchronization required to access the caches
+     * is distributed.
+     */
+    private static Map[] getConvertedCaches(String encoding) {
+        synchronized (cEncodings) {
+            Map[] caches = (Map[])cEncodings.get(encoding);
+            if (caches == null) {
+                caches = new Map[CACHES_PER_ENCODING];
+                for (int i=0; i<CACHES_PER_ENCODING; i++) {
+                    caches[i] = Collections.synchronizedMap(new IdentityMap());
+                }
+                cEncodings.put(encoding, caches);
+            }
+            return caches;
+        }
+    }
+
+    private static Random getRandom() {
+        synchronized (cLastRandom) {
+            return cLastRandom = new Random(cLastRandom.nextLong());
+        }
+    }
+
+    private CharToByteBuffer mBuffer;
+    private Random mRandom;
+    private transient Map[] mConvertedCaches;
+
+    public InternedCharToByteBuffer(CharToByteBuffer buffer)
+        throws IOException
+    {
+        mBuffer = buffer;
+        mConvertedCaches = getConvertedCaches(buffer.getEncoding());
+    }
+
+    public void setEncoding(String enc) throws IOException {
+        mBuffer.setEncoding(enc);
+        mConvertedCaches = getConvertedCaches(mBuffer.getEncoding());
+    }
+
+    public String getEncoding() throws IOException {
+        return mBuffer.getEncoding();
+    }
+
+    public long getBaseByteCount() throws IOException {
+        return mBuffer.getBaseByteCount();
+    }
+
+    public long getByteCount() throws IOException {
+        return mBuffer.getByteCount();
+    }
+    
+    public void writeTo(OutputStream out) throws IOException {
+        mBuffer.writeTo(out);
+    }
+    
+    public void append(byte b) throws IOException {
+        mBuffer.append(b);
+    }
+    
+    public void append(byte[] bytes) throws IOException {
+        mBuffer.append(bytes);
+    }
+    
+    public void append(byte[] bytes, int offset, int length)
+        throws IOException {
+
+        mBuffer.append(bytes, offset, length);
+    }
+    
+    public void appendSurrogate(ByteData s) throws IOException {
+        mBuffer.appendSurrogate(s);
+    }
+
+    public void addCaptureBuffer(ByteBuffer buffer) throws IOException {
+        mBuffer.addCaptureBuffer(buffer);
+    }
+    
+    public void removeCaptureBuffer(ByteBuffer buffer) throws IOException {
+        mBuffer.removeCaptureBuffer(buffer);
+    }
+    
+    public void append(char c) throws IOException {
+        mBuffer.append(c);
+    }
+    
+    public void append(char[] chars) throws IOException {
+        mBuffer.append(chars);
+    }
+    
+    public void append(char[] chars, int offset, int length) 
+        throws IOException {
+
+        mBuffer.append(chars, offset, length);
+    }
+    
+    public void append(String str) throws IOException {
+        Map cache;
+        if ((cache = getConvertedCache(str)) == null) {
+            mBuffer.append(str);
+            return;
+        }
+
+        // Caching performed using a two pass technique. This is done to
+        // avoid the cost of String.getBytes() for strings that aren't
+        // actually interned.
+
+        Object value;
+
+        if ((value = cache.get(str)) != null) {
+            byte[] bytes;
+            if (value != MARKER) {
+                bytes = (byte[])value;
+            }
+            else {
+                // This is at least the second time the string has been seen,
+                // so assume it has been interned and call String.getBytes().
+                String enc = getEncoding();
+                if (enc != null) {
+                    bytes = str.getBytes(enc);
+                }
+                else { 
+                    // no encoding specified so use default.
+                    bytes = str.getBytes();
+                }
+                cache.put(str, bytes);
+            }
+
+            mBuffer.append(bytes);
+        }
+        else {
+            // Just put a marker at first to indicate that the string has been
+            // seen, but don't call String.getBytes() just yet.
+            if (mRandom == null) {
+                mRandom = getRandom();
+            }
+            if ((mRandom.nextInt() % 20) == 0) {
+                // Only mark sometimes in order to reduce the amount of times
+                // put is called for strings that will never be seen again.
+                // Calculating a random number is cheaper than putting into an
+                // IdentityMap because no objects are created. A consequence of
+                // this optimization is that it will take more iterations to
+                // discover the real string literals, but they will be
+                // discovered eventually.
+                cache.put(str, MARKER);
+            }
+            mBuffer.append(str);
+        }
+    }
+    
+    public void append(String str, int offset, int length) throws IOException {
+        mBuffer.append(str, offset, length);
+    }
+
+    public void reset() throws IOException {
+        mBuffer.reset();
+    }
+
+    public void drain() throws IOException {
+        mBuffer.drain();
+    }
+
+    private Map getConvertedCache(String str) {
+        if (str.length() < MIN_LENGTH) {
+            return null;
+        }
+        return mConvertedCaches[str.charAt(1) % CACHES_PER_ENCODING];
+    }
+
+    private void readObject(ObjectInputStream in)
+        throws IOException, ClassNotFoundException
+    {
+        in.defaultReadObject();
+        mConvertedCaches = getConvertedCaches(mBuffer.getEncoding());
+    }
+}