Initial Commit

iTechSharp/srcbc/util/encoders/HexEncoder.cs

@@ -0,0 +1,164 @@
+using System;
+using System.IO;
+
+namespace Org.BouncyCastle.Utilities.Encoders
+{
+	public class HexEncoder
+		: IEncoder
+	{
+		private static readonly byte[] encodingTable =
+		{
+			(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
+			(byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'
+		};
+
+		/*
+		* set up the decoding table.
+		*/
+		internal static readonly byte[] decodingTable = new byte[128];
+
+		static HexEncoder()
+		{
+			for (int i = 0; i < encodingTable.Length; i++)
+			{
+				decodingTable[encodingTable[i]] = (byte)i;
+			}
+
+			decodingTable['A'] = decodingTable['a'];
+			decodingTable['B'] = decodingTable['b'];
+			decodingTable['C'] = decodingTable['c'];
+			decodingTable['D'] = decodingTable['d'];
+			decodingTable['E'] = decodingTable['e'];
+			decodingTable['F'] = decodingTable['f'];
+		}
+
+		/**
+		* encode the input data producing a Hex output stream.
+		*
+		* @return the number of bytes produced.
+		*/
+		public int Encode(
+			byte[]	data,
+			int		off,
+			int		length,
+			Stream	outStream)
+		{
+			for (int i = off; i < (off + length); i++)
+			{
+				int v = data[i];
+
+				outStream.WriteByte(encodingTable[v >> 4]);
+				outStream.WriteByte(encodingTable[v & 0xf]);
+			}
+
+			return length * 2;
+		}
+
+		private bool ignore(
+			char c)
+		{
+			return (c == '\n' || c =='\r' || c == '\t' || c == ' ');
+		}
+
+		/**
+		* decode the Hex encoded byte data writing it to the given output stream,
+		* whitespace characters will be ignored.
+		*
+		* @return the number of bytes produced.
+		*/
+		public int Decode(
+			byte[]	data,
+			int		off,
+			int		length,
+			Stream	outStream)
+		{
+			byte b1, b2;
+			int outLen = 0;
+			int end = off + length;
+
+			while (end > off)
+			{
+				if (!ignore((char)data[end - 1]))
+				{
+					break;
+				}
+
+				end--;
+			}
+
+			int i = off;
+			while (i < end)
+			{
+				while (i < end && ignore((char)data[i]))
+				{
+					i++;
+				}
+
+				b1 = decodingTable[data[i++]];
+
+				while (i < end && ignore((char)data[i]))
+				{
+					i++;
+				}
+
+				b2 = decodingTable[data[i++]];
+
+				outStream.WriteByte((byte)((b1 << 4) | b2));
+
+				outLen++;
+			}
+
+			return outLen;
+		}
+
+		/**
+		* decode the Hex encoded string data writing it to the given output stream,
+		* whitespace characters will be ignored.
+		*
+		* @return the number of bytes produced.
+		*/
+		public int DecodeString(
+			string	data,
+			Stream	outStream)
+		{
+			byte    b1, b2;
+			int     length = 0;
+
+			int     end = data.Length;
+
+			while (end > 0)
+			{
+				if (!ignore(data[end - 1]))
+				{
+					break;
+				}
+
+				end--;
+			}
+
+			int i = 0;
+			while (i < end)
+			{
+				while (i < end && ignore(data[i]))
+				{
+					i++;
+				}
+
+				b1 = decodingTable[data[i++]];
+
+				while (i < end && ignore(data[i]))
+				{
+					i++;
+				}
+
+				b2 = decodingTable[data[i++]];
+
+				outStream.WriteByte((byte)((b1 << 4) | b2));
+
+				length++;
+			}
+
+			return length;
+		}
+	}
+}