nethermindeth / int256 Goto Github PK

At first let's look to contructor from byte[] in litle endian mode:

                    u0 = BinaryPrimitives.ReadUInt64LittleEndian(bytes.Slice(0, 8));
                    u1 = BinaryPrimitives.ReadUInt64LittleEndian(bytes.Slice(8, 8));
                    u2 = BinaryPrimitives.ReadUInt64LittleEndian(bytes.Slice(16, 8));
                    u3 = BinaryPrimitives.ReadUInt64LittleEndian(bytes.Slice(24, 8));

And now to ToLittleEndian itself:

                BinaryPrimitives.WriteUInt64LittleEndian(target.Slice(0, 8), u3);
                BinaryPrimitives.WriteUInt64LittleEndian(target.Slice(8, 8), u2);
                BinaryPrimitives.WriteUInt64LittleEndian(target.Slice(16, 8), u1);
                BinaryPrimitives.WriteUInt64LittleEndian(target.Slice(24, 8), u0);

In constuctor we read u0 from first 8 bytes, but in ToLittleEndian we write in first 8 bytes u3 value.
So if we trying make UInt256 from ToLittleEndian we get different value.

        [Test]
        public virtual void CheckToLittleEndian()
        {
            var v = UInt256.Parse("0xfb5764948f29b38f6f4456eff35caab6741b5a19292862ff4d376a570cd473d7");
            var v2 = new UInt256(v.ToLittleEndian());
            v2.Should().Be(v);
        }

After it get out from preview features.

https://docs.microsoft.com/en-us/dotnet/api/system.inumber-1?view=net-7.0

Issue can be easily tested with this snippet:

double d = 1E+20d;
UInt256 u = (UInt256)d; 
Console.WriteLine(u);   // 0

When NM client parses something like a Dictionary from JSON where input keys look like: "0x0000000000000000000000000000000000000000000000000000000000000000" we currently fail.

This leads to dirty hacks like re-implementing dictionary parser like they do here with explicit (UInt256)BigInteger.Parse(skey.Substring(2), NumberStyles.HexNumber); in it.