Initial commit.

PerfectNumbers.Core/RationalHelper.cs

@@ -0,0 +1,35 @@
+using System.Numerics;
+using PeterO.Numbers;
+
+namespace PerfectNumbers.Core;
+
+public static class RationalHelper
+{
+    public static ERational FromDoubleRounded(double value, int scale = 100)
+    {
+        long numerator = checked((long)Math.Round(value * scale));
+        long denominator = scale;
+        long gcd = (long)BigInteger.GreatestCommonDivisor(numerator, denominator);
+        return ERational.Create(EInteger.FromInt64(numerator / gcd), EInteger.FromInt64(denominator / gcd));
+    }
+
+    public static EInteger ToEInteger(BigInteger value)
+    {
+        return EInteger.FromBytes(value.ToByteArray(), true);
+    }
+
+    public static ulong FloorToUInt64(ERational value)
+    {
+        EInteger ei = value.ToEInteger();
+        return ei.ToUInt64Checked();
+    }
+
+    public static ulong CeilingToUInt64(ERational value)
+    {
+        EInteger ei = value.ToEInteger();
+        if (value.CompareTo(ERational.Create(ei, EInteger.One)) > 0)
+            ei += EInteger.One;
+        return ei.ToUInt64Checked();
+    }
+}
+