1 files changed, 71 insertions, 0 deletions
diff --git a/server/src/main/java/com/vaadin/util/EncodeUtil.java b/server/src/main/java/com/vaadin/util/EncodeUtil.java
new file mode 100644
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+++ b/server/src/main/java/com/vaadin/util/EncodeUtil.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed 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 com.vaadin.util;
+
+import java.nio.charset.Charset;
+
+/**
+ * Utilities related to various encoding schemes.
+ *
+ * @author Vaadin Ltd
+ * @since
+ */
+public final class EncodeUtil {
+    private static final Charset UTF8 = Charset.forName("UTF-8");
+
+    private EncodeUtil() {
+        // Static utils only
+    }
+
+    /**
+     * Encodes the given string to UTF-8 <code>value-chars</code> as defined in
+     * RFC5987 for use in e.g. the <code>Content-Disposition</code> HTTP header.
+     *
+     * @param value
+     *            the string to encode, not <code>null</code>
+     * @return the encoded string
+     */
+    public static String rfc5987Encode(String value) {
+        StringBuilder builder = new StringBuilder();
+
+        for (int i = 0; i < value.length();) {
+            int cp = value.codePointAt(i);
+            if (cp < 127 && (Character.isLetterOrDigit(cp) || cp == '.')) {
+                builder.append((char) cp);
+            } else {
+                // Create string from a single code point
+                String cpAsString = new String(new int[] { cp }, 0, 1);
+
+                appendHexBytes(builder, cpAsString.getBytes(UTF8));
+            }
+
+            // Advance to the next code point
+            i += Character.charCount(cp);
+        }
+
+        return builder.toString();
+    }
+
+    private static void appendHexBytes(StringBuilder builder, byte[] bytes) {
+        for (byte byteValue : bytes) {
+            // mask with 0xFF to compensate for "negative" values
+            int intValue = byteValue & 0xFF;
+            String hexCode = Integer.toString(intValue, 16);
+            builder.append('%').append(hexCode);
+        }
+    }
+
+}