Fix strlcpy

src/LibHac/Util/StringUtils.cs

@@ -38,14 +38,15 @@ public static class StringUtils
         return i;
     }
 
-    public static int Strlcpy(Span<byte> dest, ReadOnlySpan<byte> source, int maxLen)
+    public static int Strlcpy(Span<byte> dest, ReadOnlySpan<byte> source, int size)
     {
-        int maxLenLocal = Math.Min(Math.Min(dest.Length, source.Length), maxLen);
+        int destSize = Math.Min(dest.Length, size);
 
         int i = 0;
-        if (maxLenLocal > 0)
+        if (destSize > 0)
         {
-            for (; i < maxLenLocal - 1 && source[i] != 0; i++)
+            int maxCopySize = Math.Min(destSize - 1, source.Length);
+            for (; i < maxCopySize && source[i] != 0; i++)
             {
                 dest[i] = source[i];
             }

tests/LibHac.Tests/Util/StringUtilTests.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Text;
+using LibHac.Util;
+using Xunit;
+
+namespace LibHac.Tests.Util;
+
+public class StringUtilTests
+{
+    [Theory]
+    [InlineData("abcdef", 3, 1, "", 6)]
+    [InlineData("abcdef", 3, 3, "ab", 6)]
+    [InlineData("abcdef", 3, 6, "ab", 6)]
+    [InlineData("abcdef", 6, 6, "abcde", 6)]
+    [InlineData("abcdef", 7, 6, "abcde", 6)]
+    [InlineData("abcdef", 7, 7, "abcdef", 6)]
+    [InlineData("abcdef", 10, 10, "abcdef", 6)]
+    public void Strlcpy_TestKnownInputs(string source, int destBufferSize, int size, string expected, int expectedReturnValue)
+    {
+        const byte paddingValue = (byte)'X';
+
+        byte[] src = Encoding.ASCII.GetBytes(source);
+        byte[] expectedBytes = Encoding.ASCII.GetBytes(expected);
+        byte[] dest = new byte[destBufferSize];
+        dest.AsSpan().Fill(paddingValue);
+
+        int returnValue = StringUtils.Strlcpy(dest, src, size);
+
+        Assert.Equal(expectedReturnValue, returnValue);
+
+        for (int i = 0; i < expectedBytes.Length; i++)
+        {
+            Assert.Equal(expectedBytes[i], dest[i]);
+        }
+
+        Assert.Equal(0, dest[expectedBytes.Length]);
+
+        for (int i = expectedBytes.Length + 1; i < dest.Length; i++)
+        {
+            Assert.Equal(paddingValue, dest[i]);
+        }
+    }
+}