diff --git a/crypto/src/util/encoders/BufferedDecoder.cs b/crypto/src/util/encoders/BufferedDecoder.cs
new file mode 100644
index 000000000..633cf1e97
--- /dev/null
+++ b/crypto/src/util/encoders/BufferedDecoder.cs
@@ -0,0 +1,117 @@
+using System;
+
+namespace Org.BouncyCastle.Utilities.Encoders
+{
+ /// <summary>
+ /// A buffering class to allow translation from one format to another to
+ /// be done in discrete chunks.
+ /// </summary>
+ public class BufferedDecoder
+ {
+ internal byte[] buffer;
+ internal int bufOff;
+
+ internal ITranslator translator;
+
+ /// <summary>
+ /// Create a buffered Decoder.
+ /// </summary>
+ /// <param name="translator">The translater to use.</param>
+ /// <param name="bufferSize">The size of the buffer.</param>
+ public BufferedDecoder(
+ ITranslator translator,
+ int bufferSize)
+ {
+ this.translator = translator;
+
+ if ((bufferSize % translator.GetEncodedBlockSize()) != 0)
+ {
+ throw new ArgumentException("buffer size not multiple of input block size");
+ }
+
+ buffer = new byte[bufferSize];
+// bufOff = 0;
+ }
+
+ /// <summary>
+ /// Process one byte of data.
+ /// </summary>
+ /// <param name="input">Data in.</param>
+ /// <param name="output">Byte array for the output.</param>
+ /// <param name="outOff">The offset in the output byte array to start writing from.</param>
+ /// <returns>The amount of output bytes.</returns>
+ public int ProcessByte(
+ byte input,
+ byte[] output,
+ int outOff)
+ {
+ int resultLen = 0;
+
+ buffer[bufOff++] = input;
+
+ if (bufOff == buffer.Length)
+ {
+ resultLen = translator.Decode(buffer, 0, buffer.Length, output, outOff);
+ bufOff = 0;
+ }
+
+ return resultLen;
+ }
+
+
+ /// <summary>
+ /// Process data from a byte array.
+ /// </summary>
+ /// <param name="input">The input data.</param>
+ /// <param name="inOff">Start position within input data array.</param>
+ /// <param name="len">Amount of data to process from input data array.</param>
+ /// <param name="outBytes">Array to store output.</param>
+ /// <param name="outOff">Position in output array to start writing from.</param>
+ /// <returns>The amount of output bytes.</returns>
+ public int ProcessBytes(
+ byte[] input,
+ int inOff,
+ int len,
+ byte[] outBytes,
+ int outOff)
+ {
+ if (len < 0)
+ {
+ throw new ArgumentException("Can't have a negative input length!");
+ }
+
+ int resultLen = 0;
+ int gapLen = buffer.Length - bufOff;
+
+ if (len > gapLen)
+ {
+ Array.Copy(input, inOff, buffer, bufOff, gapLen);
+
+ resultLen += translator.Decode(buffer, 0, buffer.Length, outBytes, outOff);
+
+ bufOff = 0;
+
+ len -= gapLen;
+ inOff += gapLen;
+ outOff += resultLen;
+
+ int chunkSize = len - (len % buffer.Length);
+
+ resultLen += translator.Decode(input, inOff, chunkSize, outBytes, outOff);
+
+ len -= chunkSize;
+ inOff += chunkSize;
+ }
+
+ if (len != 0)
+ {
+ Array.Copy(input, inOff, buffer, bufOff, len);
+
+ bufOff += len;
+ }
+
+ return resultLen;
+ }
+ }
+
+}
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