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java/org/apache/tomcat/util/buf/C2BConverter.java

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+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.apache.tomcat.util.buf;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.CodingErrorAction;
+
+/**
+ * NIO based character encoder.
+ */
+public final class C2BConverter {
+
+    private final CharsetEncoder encoder;
+    private ByteBuffer bb = null;
+    private CharBuffer cb = null;
+
+    /**
+     * Leftover buffer used for multi-characters characters.
+     */
+    private final CharBuffer leftovers;
+
+    public C2BConverter(Charset charset) {
+        encoder = charset.newEncoder();
+        encoder.onUnmappableCharacter(CodingErrorAction.REPLACE)
+                .onMalformedInput(CodingErrorAction.REPLACE);
+        char[] left = new char[4];
+        leftovers = CharBuffer.wrap(left);
+    }
+
+    /**
+     * Reset the encoder state.
+     */
+    public void recycle() {
+        encoder.reset();
+        leftovers.position(0);
+    }
+
+    public boolean isUndeflow() {
+        return (leftovers.position() > 0);
+    }
+
+    /**
+     * Convert the given characters to bytes.
+     *
+     * @param cc char input
+     * @param bc byte output
+     * @throws IOException An encoding error occurred
+     */
+    public void convert(CharChunk cc, ByteChunk bc) throws IOException {
+        if ((bb == null) || (bb.array() != bc.getBuffer())) {
+            // Create a new byte buffer if anything changed
+            bb = ByteBuffer.wrap(bc.getBuffer(), bc.getEnd(), bc.getBuffer().length - bc.getEnd());
+        } else {
+            // Initialize the byte buffer
+            bb.limit(bc.getBuffer().length);
+            bb.position(bc.getEnd());
+        }
+        if ((cb == null) || (cb.array() != cc.getBuffer())) {
+            // Create a new char buffer if anything changed
+            cb = CharBuffer.wrap(cc.getBuffer(), cc.getStart(), cc.getLength());
+        } else {
+            // Initialize the char buffer
+            cb.limit(cc.getEnd());
+            cb.position(cc.getStart());
+        }
+        CoderResult result = null;
+        // Parse leftover if any are present
+        if (leftovers.position() > 0) {
+            int pos = bb.position();
+            // Loop until one char is encoded or there is a encoder error
+            do {
+                leftovers.put((char) cc.substract());
+                leftovers.flip();
+                result = encoder.encode(leftovers, bb, false);
+                leftovers.position(leftovers.limit());
+                leftovers.limit(leftovers.array().length);
+            } while (result.isUnderflow() && (bb.position() == pos));
+            if (result.isError() || result.isMalformed()) {
+                result.throwException();
+            }
+            cb.position(cc.getStart());
+            leftovers.position(0);
+        }
+        // Do the decoding and get the results into the byte chunk and the char
+        // chunk
+        result = encoder.encode(cb, bb, false);
+        if (result.isError() || result.isMalformed()) {
+            result.throwException();
+        } else if (result.isOverflow()) {
+            // Propagate current positions to the byte chunk and char chunk
+            bc.setEnd(bb.position());
+            cc.setOffset(cb.position());
+        } else if (result.isUnderflow()) {
+            // Propagate current positions to the byte chunk and char chunk
+            bc.setEnd(bb.position());
+            cc.setOffset(cb.position());
+            // Put leftovers in the leftovers char buffer
+            if (cc.getLength() > 0) {
+                leftovers.limit(leftovers.array().length);
+                leftovers.position(cc.getLength());
+                cc.substract(leftovers.array(), 0, cc.getLength());
+            }
+        }
+    }
+
+    /**
+     * Convert the given characters to bytes.
+     *
+     * @param cc char input
+     * @param bc byte output
+     * @throws IOException An encoding error occurred
+     */
+    public void convert(CharBuffer cc, ByteBuffer bc) throws IOException {
+        if ((bb == null) || (bb.array() != bc.array())) {
+            // Create a new byte buffer if anything changed
+            bb = ByteBuffer.wrap(bc.array(), bc.limit(), bc.capacity() - bc.limit());
+        } else {
+            // Initialize the byte buffer
+            bb.limit(bc.capacity());
+            bb.position(bc.limit());
+        }
+        if ((cb == null) || (cb.array() != cc.array())) {
+            // Create a new char buffer if anything changed
+            cb = CharBuffer.wrap(cc.array(), cc.arrayOffset() + cc.position(), cc.remaining());
+        } else {
+            // Initialize the char buffer
+            cb.limit(cc.limit());
+            cb.position(cc.position());
+        }
+        CoderResult result = null;
+        // Parse leftover if any are present
+        if (leftovers.position() > 0) {
+            int pos = bb.position();
+            // Loop until one char is encoded or there is a encoder error
+            do {
+                leftovers.put(cc.get());
+                leftovers.flip();
+                result = encoder.encode(leftovers, bb, false);
+                leftovers.position(leftovers.limit());
+                leftovers.limit(leftovers.array().length);
+            } while (result.isUnderflow() && (bb.position() == pos));
+            if (result.isError() || result.isMalformed()) {
+                result.throwException();
+            }
+            cb.position(cc.position());
+            leftovers.position(0);
+        }
+        // Do the decoding and get the results into the byte chunk and the char
+        // chunk
+        result = encoder.encode(cb, bb, false);
+        if (result.isError() || result.isMalformed()) {
+            result.throwException();
+        } else if (result.isOverflow()) {
+            // Propagate current positions to the byte chunk and char chunk
+            bc.limit(bb.position());
+            cc.position(cb.position());
+        } else if (result.isUnderflow()) {
+            // Propagate current positions to the byte chunk and char chunk
+            bc.limit(bb.position());
+            cc.position(cb.position());
+            // Put leftovers in the leftovers char buffer
+            if (cc.remaining() > 0) {
+                leftovers.limit(leftovers.array().length);
+                leftovers.position(cc.remaining());
+                cc.get(leftovers.array(), 0, cc.remaining());
+            }
+        }
+    }
+
+    public Charset getCharset() {
+        return encoder.charset();
+    }
+}