1 files changed, 241 insertions, 0 deletions
diff --git a/crypto/src/math/ec/abc/SimpleBigDecimal.cs b/crypto/src/math/ec/abc/SimpleBigDecimal.cs
new file mode 100644
index 000000000..d5664dbfd
--- /dev/null
+++ b/crypto/src/math/ec/abc/SimpleBigDecimal.cs
@@ -0,0 +1,241 @@
+using System;
+using System.Text;
+
+namespace Org.BouncyCastle.Math.EC.Abc
+{
+	/**
+	* Class representing a simple version of a big decimal. A
+	* <code>SimpleBigDecimal</code> is basically a
+	* {@link java.math.BigInteger BigInteger} with a few digits on the right of
+	* the decimal point. The number of (binary) digits on the right of the decimal
+	* point is called the <code>scale</code> of the <code>SimpleBigDecimal</code>.
+	* Unlike in {@link java.math.BigDecimal BigDecimal}, the scale is not adjusted
+	* automatically, but must be set manually. All <code>SimpleBigDecimal</code>s
+	* taking part in the same arithmetic operation must have equal scale. The
+	* result of a multiplication of two <code>SimpleBigDecimal</code>s returns a
+	* <code>SimpleBigDecimal</code> with double scale.
+	*/
+	internal class SimpleBigDecimal
+		//	: Number
+	{
+		//	private static final long serialVersionUID = 1L;
+
+		private readonly BigInteger	bigInt;
+		private readonly int		scale;
+
+		/**
+		* Returns a <code>SimpleBigDecimal</code> representing the same numerical
+		* value as <code>value</code>.
+		* @param value The value of the <code>SimpleBigDecimal</code> to be
+		* created. 
+		* @param scale The scale of the <code>SimpleBigDecimal</code> to be
+		* created. 
+		* @return The such created <code>SimpleBigDecimal</code>.
+		*/
+		public static SimpleBigDecimal GetInstance(BigInteger val, int scale)
+		{
+			return new SimpleBigDecimal(val.ShiftLeft(scale), scale);
+		}
+
+		/**
+		* Constructor for <code>SimpleBigDecimal</code>. The value of the
+		* constructed <code>SimpleBigDecimal</code> Equals <code>bigInt / 
+		* 2<sup>scale</sup></code>.
+		* @param bigInt The <code>bigInt</code> value parameter.
+		* @param scale The scale of the constructed <code>SimpleBigDecimal</code>.
+		*/
+		public SimpleBigDecimal(BigInteger bigInt, int scale)
+		{
+			if (scale < 0)
+				throw new ArgumentException("scale may not be negative");
+
+			this.bigInt = bigInt;
+			this.scale = scale;
+		}
+
+		private SimpleBigDecimal(SimpleBigDecimal limBigDec)
+		{
+			bigInt = limBigDec.bigInt;
+			scale = limBigDec.scale;
+		}
+
+		private void CheckScale(SimpleBigDecimal b)
+		{
+			if (scale != b.scale)
+				throw new ArgumentException("Only SimpleBigDecimal of same scale allowed in arithmetic operations");
+		}
+
+		public SimpleBigDecimal AdjustScale(int newScale)
+		{
+			if (newScale < 0)
+				throw new ArgumentException("scale may not be negative");
+
+			if (newScale == scale)
+				return this;
+
+			return new SimpleBigDecimal(bigInt.ShiftLeft(newScale - scale), newScale);
+		}
+
+		public SimpleBigDecimal Add(SimpleBigDecimal b)
+		{
+			CheckScale(b);
+			return new SimpleBigDecimal(bigInt.Add(b.bigInt), scale);
+		}
+
+		public SimpleBigDecimal Add(BigInteger b)
+		{
+			return new SimpleBigDecimal(bigInt.Add(b.ShiftLeft(scale)), scale);
+		}
+
+		public SimpleBigDecimal Negate()
+		{
+			return new SimpleBigDecimal(bigInt.Negate(), scale);
+		}
+
+		public SimpleBigDecimal Subtract(SimpleBigDecimal b)
+		{
+			return Add(b.Negate());
+		}
+
+		public SimpleBigDecimal Subtract(BigInteger b)
+		{
+			return new SimpleBigDecimal(bigInt.Subtract(b.ShiftLeft(scale)), scale);
+		}
+
+		public SimpleBigDecimal Multiply(SimpleBigDecimal b)
+		{
+			CheckScale(b);
+			return new SimpleBigDecimal(bigInt.Multiply(b.bigInt), scale + scale);
+		}
+
+		public SimpleBigDecimal Multiply(BigInteger b)
+		{
+			return new SimpleBigDecimal(bigInt.Multiply(b), scale);
+		}
+
+		public SimpleBigDecimal Divide(SimpleBigDecimal b)
+		{
+			CheckScale(b);
+			BigInteger dividend = bigInt.ShiftLeft(scale);
+			return new SimpleBigDecimal(dividend.Divide(b.bigInt), scale);
+		}
+
+		public SimpleBigDecimal Divide(BigInteger b)
+		{
+			return new SimpleBigDecimal(bigInt.Divide(b), scale);
+		}
+
+		public SimpleBigDecimal ShiftLeft(int n)
+		{
+			return new SimpleBigDecimal(bigInt.ShiftLeft(n), scale);
+		}
+
+		public int CompareTo(SimpleBigDecimal val)
+		{
+			CheckScale(val);
+			return bigInt.CompareTo(val.bigInt);
+		}
+
+		public int CompareTo(BigInteger val)
+		{
+			return bigInt.CompareTo(val.ShiftLeft(scale));
+		}
+
+		public BigInteger Floor()
+		{
+			return bigInt.ShiftRight(scale);
+		}
+
+		public BigInteger Round()
+		{
+			SimpleBigDecimal oneHalf = new SimpleBigDecimal(BigInteger.One, 1);
+			return Add(oneHalf.AdjustScale(scale)).Floor();
+		}
+
+		public int IntValue
+		{
+			get { return Floor().IntValue; }
+		}
+
+		public long LongValue
+		{
+			get { return Floor().LongValue; }
+		}
+
+//		public double doubleValue()
+//		{
+//			return new Double(ToString()).doubleValue();
+//		}
+//
+//		public float floatValue()
+//		{
+//			return new Float(ToString()).floatValue();
+//		}
+
+		public int Scale
+		{
+			get { return scale; }
+		}
+
+		public override string ToString()
+		{
+			if (scale == 0)
+				return bigInt.ToString();
+
+			BigInteger floorBigInt = Floor();
+	        
+			BigInteger fract = bigInt.Subtract(floorBigInt.ShiftLeft(scale));
+			if (bigInt.SignValue < 0)
+			{
+				fract = BigInteger.One.ShiftLeft(scale).Subtract(fract);
+			}
+
+			if ((floorBigInt.SignValue == -1) && (!(fract.Equals(BigInteger.Zero))))
+			{
+				floorBigInt = floorBigInt.Add(BigInteger.One);
+			}
+			string leftOfPoint = floorBigInt.ToString();
+
+			char[] fractCharArr = new char[scale];
+				string fractStr = fract.ToString(2);
+			int fractLen = fractStr.Length;
+			int zeroes = scale - fractLen;
+			for (int i = 0; i < zeroes; i++)
+			{
+				fractCharArr[i] = '0';
+			}
+			for (int j = 0; j < fractLen; j++)
+			{
+				fractCharArr[zeroes + j] = fractStr[j];
+			}
+			string rightOfPoint = new string(fractCharArr);
+
+			StringBuilder sb = new StringBuilder(leftOfPoint);
+			sb.Append(".");
+			sb.Append(rightOfPoint);
+
+			return sb.ToString();
+		}
+
+		public override bool Equals(
+			object obj)
+		{
+			if (this == obj)
+				return true;
+
+			SimpleBigDecimal other = obj as SimpleBigDecimal;
+
+			if (other == null)
+				return false;
+
+			return bigInt.Equals(other.bigInt)
+				&& scale == other.scale;
+		}
+
+		public override int GetHashCode()
+		{
+			return bigInt.GetHashCode() ^ scale;
+		}
+
+	}
+}