fix: fix order of bytes in decimal write bytes methods

CHANGELOG.md

@@ -58,6 +58,7 @@ TypeInitializationException.
 
 ### Fixed
 
+- X10D: Fixed `decimal.TryWriteBigEndianBytes` and `decimal.TryWriteLittleEndianBytes`.
 - X10D.Hosting: Fixed `AddHostedSingleton` not accepting an interface as the service type.
 
 ## [3.3.0] - 2023-08-21

X10D.Tests/src/IO/DecimalTests.cs

@@ -0,0 +1,54 @@
+using NUnit.Framework;
+using X10D.IO;
+
+namespace X10D.Tests.IO;
+
+[TestFixture]
+internal class DecimalTests
+{
+    [Test]
+    public void GetBigEndianBytes_ShouldReturnBytes_InBigEndian()
+    {
+        const decimal value = 1234m;
+        byte[] expected = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 210];
+
+        byte[] bytes = value.GetBigEndianBytes();
+
+        CollectionAssert.AreEqual(expected, bytes);
+    }
+
+    [Test]
+    public void GetLittleEndianBytes_ShouldReturnBytes_InLittleEndian()
+    {
+        const decimal value = 1234m;
+        byte[] expected = [210, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+
+        byte[] bytes = value.GetLittleEndianBytes();
+
+        CollectionAssert.AreEqual(expected, bytes);
+    }
+
+    [Test]
+    public void TryWriteBigEndianBytes_ShouldWriteBytes_InBigEndian()
+    {
+        const decimal value = 1234m;
+        byte[] expected = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 210];
+
+        Span<byte> bytes = stackalloc byte[16];
+        value.TryWriteBigEndianBytes(bytes);
+
+        CollectionAssert.AreEqual(expected, bytes.ToArray());
+    }
+
+    [Test]
+    public void TryWriteLittleEndianBytes_ShouldWriteBytes_InLittleEndian()
+    {
+        const decimal value = 1234m;
+        byte[] expected = [210, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+
+        Span<byte> bytes = stackalloc byte[16];
+        value.TryWriteLittleEndianBytes(bytes);
+
+        CollectionAssert.AreEqual(expected, bytes.ToArray());
+    }
+}

X10D.Tests/src/IO/StreamTests.WriteDecimal.cs

@@ -48,9 +48,10 @@ internal partial class StreamTests
         Span<byte> actual = stackalloc byte[16];
         ReadOnlySpan<byte> expected = stackalloc byte[]
         {
-            0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x68, 0x10, 0x00, 0x00
+            0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x68
         };
         int read = stream.Read(actual);
+        Trace.WriteLine(string.Join(' ', actual.ToArray()));
 
         Assert.That(read, Is.EqualTo(16));
         CollectionAssert.AreEqual(expected.ToArray(), actual.ToArray());

X10D/src/IO/DecimalExtensions.cs

@@ -1,4 +1,3 @@
-using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.Runtime.InteropServices;
 
@@ -13,11 +12,11 @@ public static class DecimalExtensions
     ///     Converts the current decimal number into an array of bytes, as little endian.
     /// </summary>
     /// <param name="value">The <see cref="int" /> value.</param>
-    /// <returns>An array of bytes with length 4.</returns>
+    /// <returns>An array of bytes with length 16.</returns>
     [Pure]
     public static byte[] GetBigEndianBytes(this decimal value)
     {
-        Span<byte> buffer = stackalloc byte[4];
+        Span<byte> buffer = stackalloc byte[16];
         value.TryWriteBigEndianBytes(buffer);
         return buffer.ToArray();
     }
@@ -26,11 +25,11 @@ public static class DecimalExtensions
     ///     Converts the current decimal number into an array of bytes, as little endian.
     /// </summary>
     /// <param name="value">The <see cref="int" /> value.</param>
-    /// <returns>An array of bytes with length 4.</returns>
+    /// <returns>An array of bytes with length 16.</returns>
     [Pure]
     public static byte[] GetLittleEndianBytes(this decimal value)
     {
-        Span<byte> buffer = stackalloc byte[4];
+        Span<byte> buffer = stackalloc byte[16];
         value.TryWriteLittleEndianBytes(buffer);
         return buffer.ToArray();
     }
@@ -44,23 +43,17 @@ public static class DecimalExtensions
     public static bool TryWriteBigEndianBytes(this decimal value, Span<byte> destination)
     {
         Span<int> buffer = stackalloc int[4];
-        GetBits(value, buffer);
+        decimal.GetBits(value, buffer);
+
+        Span<byte> result = stackalloc byte[16];
+        MemoryMarshal.Cast<int, byte>(buffer).CopyTo(result);
 
-        if (buffer[0].TryWriteBigEndianBytes(destination[..4]) &&
-            buffer[1].TryWriteBigEndianBytes(destination[4..8]) &&
-            buffer[2].TryWriteBigEndianBytes(destination[8..12]) &&
-            buffer[3].TryWriteBigEndianBytes(destination[12..]))
-        {
         if (BitConverter.IsLittleEndian)
         {
-                destination.Reverse();
+            result.Reverse();
         }
 
-            return true;
+        return result.TryCopyTo(destination);
-        }
-
-        destination.Clear();
-        return false;
     }
 
     /// <summary>
@@ -72,44 +65,16 @@ public static class DecimalExtensions
     public static bool TryWriteLittleEndianBytes(this decimal value, Span<byte> destination)
     {
         Span<int> buffer = stackalloc int[4];
-        GetBits(value, buffer);
+        decimal.GetBits(value, buffer);
+
+        Span<byte> result = stackalloc byte[16];
+        MemoryMarshal.Cast<int, byte>(buffer).CopyTo(result);
 
-        if (buffer[0].TryWriteLittleEndianBytes(destination[..4]) &&
-            buffer[1].TryWriteLittleEndianBytes(destination[4..8]) &&
-            buffer[2].TryWriteLittleEndianBytes(destination[8..12]) &&
-            buffer[3].TryWriteLittleEndianBytes(destination[12..]))
-        {
         if (!BitConverter.IsLittleEndian)
         {
-                destination.Reverse();
+            result.Reverse();
         }
 
-            return true;
+        return result.TryCopyTo(destination);
     }
-
-        destination.Clear();
-        return false;
-    }
-
-    private static void GetBits(decimal value, Span<int> destination)
-    {
-        _ = decimal.GetBits(value, destination);
-    }
-
-#if !NET5_0_OR_GREATER
-    private static void WriteBits(Span<int> destination, Span<byte> buffer)
-    {
-        var flags = MemoryMarshal.Read<int>(buffer[..4]);
-        var hi = MemoryMarshal.Read<int>(buffer[4..8]);
-        var lo = MemoryMarshal.Read<long>(buffer[8..]);
-
-        var low = (uint)lo;
-        var mid = (uint)(lo >> 32);
-
-        destination[0] = (int)low;
-        destination[1] = (int)mid;
-        destination[2] = hi;
-        destination[3] = flags;
-    }
-#endif
 }