Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.IdentityModel/System/IdentityModel/CanonicalFormWriter.cs

@@ -0,0 +1,95 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+
+namespace System.IdentityModel
+{
+    using System.IO;
+    using System.Security.Cryptography;
+    using System.Text;
+    using System.Xml;
+
+    abstract class CanonicalFormWriter
+    {
+        internal static readonly UTF8Encoding Utf8WithoutPreamble = new UTF8Encoding(false);
+
+        protected static void Base64EncodeAndWrite(Stream stream, byte[] workBuffer, char[] base64WorkBuffer, byte[] data)
+        {
+            if ((data.Length / 3) * 4 + 4 > base64WorkBuffer.Length)
+            {
+                EncodeAndWrite(stream, Convert.ToBase64String(data));
+                return;
+            }
+
+            int encodedLength = Convert.ToBase64CharArray(data, 0, data.Length, base64WorkBuffer, 0, Base64FormattingOptions.None);
+            EncodeAndWrite(stream, workBuffer, base64WorkBuffer, encodedLength);
+        }
+
+        protected static void EncodeAndWrite(Stream stream, byte[] workBuffer, string s)
+        {
+            if (s.Length > workBuffer.Length)
+            {
+                EncodeAndWrite(stream, s);
+                return;
+            }
+
+            for (int i = 0; i < s.Length; i++)
+            {
+                char c = s[i];
+                if (c < 127)
+                {
+                    workBuffer[i] = (byte) c;
+                }
+                else
+                {
+                    EncodeAndWrite(stream, s);
+                    return;
+                }
+            }
+
+            stream.Write(workBuffer, 0, s.Length);
+        }
+
+        protected static void EncodeAndWrite(Stream stream, byte[] workBuffer, char[] chars)
+        {
+            EncodeAndWrite(stream, workBuffer, chars, chars.Length);
+        }
+
+        protected static void EncodeAndWrite(Stream stream, byte[] workBuffer, char[] chars, int count)
+        {
+            if (count > workBuffer.Length)
+            {
+                EncodeAndWrite(stream, chars, count);
+                return;
+            }
+
+            for (int i = 0; i < count; i++)
+            {
+                char c = chars[i];
+                if (c < 127)
+                {
+                    workBuffer[i] = (byte) c;
+                }
+                else
+                {
+                    EncodeAndWrite(stream, chars, count);
+                    return;
+                }
+            }
+
+            stream.Write(workBuffer, 0, count);
+        }
+
+        static void EncodeAndWrite(Stream stream, string s)
+        {
+            byte[] buffer = CanonicalFormWriter.Utf8WithoutPreamble.GetBytes(s);
+            stream.Write(buffer, 0, buffer.Length);
+        }
+
+        static void EncodeAndWrite(Stream stream, char[] chars, int count)
+        {
+            byte[] buffer = CanonicalFormWriter.Utf8WithoutPreamble.GetBytes(chars, 0, count);
+            stream.Write(buffer, 0, buffer.Length);
+        }
+    }
+}