THRIFT-323. csharp: TJSONProtocol

This patch adds support for the JSON Protocol to the csharp library. 

Patch: Roger Meier

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@998539 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/csharp/src/Protocol/TBase64Utils.cs b/lib/csharp/src/Protocol/TBase64Utils.cs
new file mode 100644
index 0000000..f857d6f
--- /dev/null
+++ b/lib/csharp/src/Protocol/TBase64Utils.cs
@@ -0,0 +1,100 @@
+/**
+ * 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.
+ */
+
+using System;
+
+namespace Thrift.Protocol
+{
+	internal static class TBase64Utils
+	{
+		internal const string ENCODE_TABLE =
+			"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+		internal static void encode(byte[] src, int srcOff, int len, byte[] dst,
+								int dstOff)
+		{
+			dst[dstOff] = (byte)ENCODE_TABLE[(src[srcOff] >> 2) & 0x3F];
+			if (len == 3)
+			{
+				dst[dstOff + 1] =
+					(byte)ENCODE_TABLE[
+						((src[srcOff] << 4) + (src[srcOff + 1] >> 4)) & 0x3F];
+				dst[dstOff + 2] =
+					(byte)ENCODE_TABLE[
+						((src[srcOff + 1] << 2) + (src[srcOff + 2] >> 6)) & 0x3F];
+				dst[dstOff + 3] =
+					(byte)ENCODE_TABLE[src[srcOff + 2] & 0x3F];
+			}
+			else if (len == 2)
+			{
+				dst[dstOff + 1] =
+					(byte)ENCODE_TABLE[
+						((src[srcOff] << 4) + (src[srcOff + 1] >> 4)) & 0x3F];
+				dst[dstOff + 2] =
+					(byte)ENCODE_TABLE[(src[srcOff + 1] << 2) & 0x3F];
+
+			}
+			else
+			{ // len == 1) {
+				dst[dstOff + 1] =
+					(byte)ENCODE_TABLE[(src[srcOff] << 4) & 0x3F];
+			}
+		}
+
+		private static int[] DECODE_TABLE = {
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
+			52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1,
+			-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
+			15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
+			-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
+			41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+			-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+		};
+
+		internal static void decode(byte[] src, int srcOff, int len, byte[] dst,
+								 int dstOff)
+		{
+			dst[dstOff] = (byte)
+				((DECODE_TABLE[src[srcOff] & 0x0FF] << 2) |
+				(DECODE_TABLE[src[srcOff + 1] & 0x0FF] >> 4));
+			if (len > 2)
+			{
+				dst[dstOff + 1] = (byte)
+					(((DECODE_TABLE[src[srcOff + 1] & 0x0FF] << 4) & 0xF0) |
+					(DECODE_TABLE[src[srcOff + 2] & 0x0FF] >> 2));
+				if (len > 3)
+				{
+					dst[dstOff + 2] = (byte)
+						(((DECODE_TABLE[src[srcOff + 2] & 0x0FF] << 6) & 0xC0) |
+						DECODE_TABLE[src[srcOff + 3] & 0x0FF]);
+				}
+			}
+		}
+
+	}
+}