Initial Commit

iTechSharp/srcbc/asn1/x9/X9IntegerConverter.cs

@@ -0,0 +1,46 @@
+using System;
+
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Math.EC;
+
+namespace Org.BouncyCastle.Asn1.X9
+{
+    public sealed class X9IntegerConverter
+    {
+		private X9IntegerConverter()
+		{
+		}
+
+		public static int GetByteLength(
+            ECFieldElement fe)
+        {
+			return (fe.FieldSize + 7) / 8;
+        }
+
+		public static int GetByteLength(
+			ECCurve c)
+		{
+			return (c.FieldSize + 7) / 8;
+		}
+
+		public static byte[] IntegerToBytes(
+            BigInteger	s,
+            int			qLength)
+        {
+			// TODO Add methods to allow writing BigInteger to existing byte array?
+			byte[] bytes = s.ToByteArrayUnsigned();
+
+			if (bytes.Length > qLength)
+				throw new ArgumentException("s does not fit in specified number of bytes", "s");
+
+			if (qLength > bytes.Length)
+            {
+                byte[] tmp = new byte[qLength];
+                Array.Copy(bytes, 0, tmp, tmp.Length - bytes.Length, bytes.Length);
+                return tmp;
+            }
+
+			return bytes;
+        }
+    }
+}