Start Url Encode implementation

sdk/src/Core/Amazon.Util/AWSSDKUtils.cs

@@ -20,6 +20,7 @@
 
 using Amazon.Runtime.Internal.Util;
 using System;
+using System.Buffers;
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
@@ -1107,35 +1108,67 @@ public static string UrlEncode(string data, bool path)
  /// Currently recognised RFC versions are 1738 (Dec '94) and 3986 (Jan '05). 
  /// If the specified RFC is not recognised, 3986 is used by default.
  /// </remarks>
+ // TODO Add SkipsLocalsInit?
  public static string UrlEncode(int rfcNumber, string data, bool path)
  {
- StringBuilder encoded = new StringBuilder(data.Length * 2);
- string validUrlCharacters;
- if (!RFCEncodingSchemes.TryGetValue(rfcNumber, out validUrlCharacters))
- validUrlCharacters = ValidUrlCharacters;
+ byte[] sharedDataBuffer = null, sharedEncodedBuffer = null;
+ // Put this elsewhere?
+ const int MaxStackLimit = 256;
+ try
+ {
+ string validUrlCharacters;
+ if (!RFCEncodingSchemes.TryGetValue(rfcNumber, out validUrlCharacters))
+ validUrlCharacters = ValidUrlCharacters;
+
+ string unreservedChars = String.Concat(validUrlCharacters, (path ? ValidPathCharacters : ""));
+
+ var dataAsSpan = data.AsSpan();
+ var encoding = Encoding.UTF8;
+
+ var dataByteLength = encoding.GetMaxByteCount(dataAsSpan.Length);
+ var dataBuffer = dataByteLength <= MaxStackLimit
+ ? stackalloc byte[MaxStackLimit]
+ : sharedDataBuffer = ArrayPool<byte>.Shared.Rent(dataByteLength);
+ var bytesWritten = encoding.GetBytes(dataAsSpan, dataBuffer);
+
+ var encodedByteLength = dataByteLength * dataByteLength;
+ var encodedBuffer = encodedByteLength <= MaxStackLimit
+ ? stackalloc byte[MaxStackLimit]
+ : sharedEncodedBuffer = ArrayPool<byte>.Shared.Rent(encodedByteLength);
+ int index = 0;
+ foreach (byte symbol in dataBuffer.Slice(0, bytesWritten))
+ {
+ if (unreservedChars.IndexOf((char)symbol) != -1)
+ {
+ encodedBuffer[index++] = symbol;
+ }
+ else
+ {
+ encodedBuffer[index++] = (byte)'%';
+
+ // Break apart the byte into two four-bit components and
+ // then convert each into their hexadecimal equivalent.
+ int hiNibble = symbol >> 4;
+ int loNibble = symbol & 0xF;
+ encodedBuffer[index++] = (byte)ToUpperHex(hiNibble);
+ encodedBuffer[index++] = (byte)ToUpperHex(loNibble);
+ }
+ }
 
- string unreservedChars = String.Concat(validUrlCharacters, (path ? ValidPathCharacters : ""));
- foreach (char symbol in System.Text.Encoding.UTF8.GetBytes(data))
+ return encoding.GetString(encodedBuffer.Slice(index));
+ }
+ finally
  {
- if (unreservedChars.IndexOf(symbol) != -1)
+ if (sharedDataBuffer != null)
  {
- encoded.Append(symbol);
+ ArrayPool<byte>.Shared.Return(sharedDataBuffer);
  }
- else
+
+ if (sharedEncodedBuffer != null)
  {
- encoded.Append('%');
-
- // Break apart the byte into two four-bit components and
- // then convert each into their hexadecimal equivalent.
- byte b = (byte)symbol;
- int hiNibble = b >> 4;
- int loNibble = b & 0xF;
- encoded.Append(ToUpperHex(hiNibble));
- encoded.Append(ToUpperHex(loNibble));
+ ArrayPool<byte>.Shared.Return(sharedEncodedBuffer);
  }
  }
-
- return encoded.ToString();
  }
 
  private static char ToUpperHex(int value)