init

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

@@ -0,0 +1,167 @@
+/*
+ *  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.charset.StandardCharsets;
+import java.util.BitSet;
+
+/**
+ * Efficient implementation of an UTF-8 encoder.
+ * This class is not thread safe - you need one encoder per thread.
+ * The encoder will save and recycle the internal objects, avoiding
+ * garbage.
+ *
+ * You can add extra characters that you want preserved, for example
+ * while encoding a URL you can add "/".
+ *
+ * @author Costin Manolache
+ */
+public final class UEncoder {
+
+    public enum SafeCharsSet {
+        WITH_SLASH("/"), DEFAULT("");
+        private final BitSet safeChars;
+
+        private BitSet getSafeChars() {
+            return this.safeChars;
+        }
+
+        private SafeCharsSet(String additionalSafeChars) {
+            safeChars = initialSafeChars();
+            for (char c : additionalSafeChars.toCharArray()) {
+                safeChars.set(c);
+            }
+        }
+    }
+
+    // Not static - the set may differ ( it's better than adding
+    // an extra check for "/", "+", etc
+    private BitSet safeChars=null;
+    private C2BConverter c2b=null;
+    private ByteChunk bb=null;
+    private CharChunk cb=null;
+    private CharChunk output=null;
+
+    /**
+     * Create a UEncoder with an unmodifiable safe character set.
+     *
+     * @param safeCharsSet safe characters for this encoder
+     */
+    public UEncoder(SafeCharsSet safeCharsSet) {
+        this.safeChars = safeCharsSet.getSafeChars();
+    }
+
+   /**
+    * URL Encode string, using a specified encoding.
+    *
+    * @param s string to be encoded
+    * @param start the beginning index, inclusive
+    * @param end the ending index, exclusive
+    *
+    * @return A new CharChunk contained the URL encoded string
+    *
+    * @throws IOException If an I/O error occurs
+    */
+   public CharChunk encodeURL(String s, int start, int end)
+       throws IOException {
+       if (c2b == null) {
+           bb = new ByteChunk(8); // small enough.
+           cb = new CharChunk(2); // small enough.
+           output = new CharChunk(64); // small enough.
+           c2b = new C2BConverter(StandardCharsets.UTF_8);
+       } else {
+           bb.recycle();
+           cb.recycle();
+           output.recycle();
+       }
+
+       for (int i = start; i < end; i++) {
+           char c = s.charAt(i);
+           if (safeChars.get(c)) {
+               output.append(c);
+           } else {
+               cb.append(c);
+               c2b.convert(cb, bb);
+
+               // "surrogate" - UTF is _not_ 16 bit, but 21 !!!!
+               // ( while UCS is 31 ). Amazing...
+               if (c >= 0xD800 && c <= 0xDBFF) {
+                   if ((i+1) < end) {
+                       char d = s.charAt(i+1);
+                       if (d >= 0xDC00 && d <= 0xDFFF) {
+                           cb.append(d);
+                           c2b.convert(cb, bb);
+                           i++;
+                       }
+                   }
+               }
+
+               urlEncode(output, bb);
+               cb.recycle();
+               bb.recycle();
+           }
+       }
+
+       return output;
+   }
+
+   protected void urlEncode(CharChunk out, ByteChunk bb)
+       throws IOException {
+       byte[] bytes = bb.getBuffer();
+       for (int j = bb.getStart(); j < bb.getEnd(); j++) {
+           out.append('%');
+           char ch = Character.forDigit((bytes[j] >> 4) & 0xF, 16);
+           out.append(ch);
+           ch = Character.forDigit(bytes[j] & 0xF, 16);
+           out.append(ch);
+       }
+   }
+
+    // -------------------- Internal implementation --------------------
+
+    private static BitSet initialSafeChars() {
+        BitSet initialSafeChars=new BitSet(128);
+        int i;
+        for (i = 'a'; i <= 'z'; i++) {
+            initialSafeChars.set(i);
+        }
+        for (i = 'A'; i <= 'Z'; i++) {
+            initialSafeChars.set(i);
+        }
+        for (i = '0'; i <= '9'; i++) {
+            initialSafeChars.set(i);
+        }
+        //safe
+        initialSafeChars.set('$');
+        initialSafeChars.set('-');
+        initialSafeChars.set('_');
+        initialSafeChars.set('.');
+
+        // Dangerous: someone may treat this as " "
+        // RFC1738 does allow it, it's not reserved
+        //    initialSafeChars.set('+');
+        //extra
+        initialSafeChars.set('!');
+        initialSafeChars.set('*');
+        initialSafeChars.set('\'');
+        initialSafeChars.set('(');
+        initialSafeChars.set(')');
+        initialSafeChars.set(',');
+        return initialSafeChars;
+    }
+}