Add SkipPadding to BinaryWriterExtensions and fix missing guard in BinaryReaderExtensions

PowerKit.Tests/BinaryWriterExtensionsTests.cs

@@ -8,6 +8,38 @@ namespace PowerKit.Tests;
 
 public class BinaryWriterExtensionsTests
 {
+    [Fact]
+    public void SkipPadding_Test()
+    {
+        // Arrange
+        using var stream = new MemoryStream();
+        using var writer = new BinaryWriter(stream);
+
+        writer.Write((byte)0x01); // advance to position 1
+
+        // Act
+        writer.SkipPadding(boundaryBytes: 4);
+
+        // Assert
+        stream.Position.Should().Be(4);
+        stream.ToArray().Should().Equal(0x01, 0x00, 0x00, 0x00);
+    }
+
+    [Fact]
+    public void SkipPadding_AlreadyAligned_Test()
+    {
+        // Arrange
+        using var stream = new MemoryStream();
+        using var writer = new BinaryWriter(stream);
+
+        // Act (position 0 is already aligned to 4 bytes)
+        writer.SkipPadding(boundaryBytes: 4);
+
+        // Assert
+        stream.Position.Should().Be(0);
+        stream.ToArray().Should().BeEmpty();
+    }
+
     [Fact]
     public void WriteNullTerminatedString_Test()
     {

PowerKit/Extensions/BinaryReaderExtensions.cs

@@ -1,4 +1,5 @@
 #nullable enable
+using System;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Text;
@@ -25,6 +26,9 @@ internal static class BinaryReaderExtensions
         /// </summary>
         public void SkipPadding(int boundaryBytes = 4)
         {
+            if (boundaryBytes <= 0)
+                throw new ArgumentOutOfRangeException(nameof(boundaryBytes));
+
             while (!reader.IsEndOfStream && reader.BaseStream.Position % boundaryBytes != 0)
             {
                 _ = reader.ReadByte();

PowerKit/Extensions/BinaryWriterExtensions.cs

@@ -1,4 +1,5 @@
 #nullable enable
+using System;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 
@@ -11,6 +12,20 @@ internal static class BinaryWriterExtensions
 {
     extension(BinaryWriter writer)
     {
+        /// <summary>
+        /// Writes zero bytes until the current position is aligned to the specified byte boundary.
+        /// </summary>
+        public void SkipPadding(int boundaryBytes = 4)
+        {
+            if (boundaryBytes <= 0)
+                throw new ArgumentOutOfRangeException(nameof(boundaryBytes));
+
+            while (writer.BaseStream.Position % boundaryBytes != 0)
+            {
+                writer.Write((byte)0);
+            }
+        }
+
         /// <summary>
         /// Writes a null-terminated string to the binary writer.
         /// </summary>