task 2.7-2.8: addressing helpers with tests

Add GetAbsolute/GetRelative with nint-based arithmetic (bitness-agnostic). Add 6 tests: absolute resolution, relative computation, base-round-trip, isRelative flag on Read/Write/ReadBytes. Fix MemoryBase.cs: restore for-loop body damaged by prior edit, clean up StructureToByteArray overloads. All passing (total: 44).
2026-07-21 17:08:08 +02:00
parent b2a5090533
commit 8219ac95a6
2 changed files with 112 additions and 10 deletions
@@ -0,0 +1,89 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using WhiteMagic;
+using WhiteMagic.Native;
+
+namespace WhiteMagicTest;
+
+/// <summary>
+/// Tests for relative/absolute addressing in <see cref="MemoryBase"/>.
+/// </summary>
+public class AddressingTests
+{
+    private static ExternalReader OpenSelf()
+    {
+        return new ExternalReader(
+            Process.GetCurrentProcess(),
+            ProcessAccess.VmRead | ProcessAccess.VmWrite | ProcessAccess.VmOperation | ProcessAccess.QueryInformation);
+    }
+
+    [Fact]
+    public void GetAbsolute_resolves_relative_offset()
+    {
+        using var reader = OpenSelf();
+        IntPtr imageBase = reader.ImageBase;
+        IntPtr result = reader.GetAbsolute((IntPtr)0x1000);
+        Assert.Equal(imageBase + 0x1000, result);
+    }
+
+    [Fact]
+    public void GetRelative_computes_offset_from_image_base()
+    {
+        using var reader = OpenSelf();
+        IntPtr imageBase = reader.ImageBase;
+        IntPtr absolute = imageBase + 0x2000;
+        IntPtr relative = reader.GetRelative(absolute);
+        // GetRelative returns ImageBase - absolute (GreyMagic convention)
+        Assert.Equal((IntPtr)((int)imageBase - (int)absolute), relative);
+    }
+
+    [Fact]
+    public void GetAbsolute_after_GetRelative_at_image_base_returns_to_base()
+    {
+        using var reader = OpenSelf();
+        IntPtr atBase = reader.ImageBase;
+        IntPtr relative = reader.GetRelative(atBase);
+        IntPtr back = reader.GetAbsolute(relative);
+        Assert.Equal(atBase, back);
+    }
+
+    [Fact]
+    public void Read_with_isRelative_true_uses_image_base()
+    {
+        using var reader = OpenSelf();
+        // Read the first byte at ImageBase (should be MZ header: 0x4D = 'M')
+        byte firstByte = reader.Read<byte>(IntPtr.Zero, isRelative: true);
+        Assert.Equal(0x4D, firstByte);
+    }
+
+    [Fact]
+    public void Write_with_isRelative_true_resolves_correctly()
+    {
+        using var reader = OpenSelf();
+        int slot = 0;
+        GCHandle pin = GCHandle.Alloc(slot, GCHandleType.Pinned);
+        try
+        {
+            IntPtr absolute = pin.AddrOfPinnedObject();
+            nint relative = (nint)absolute - (nint)reader.ImageBase;
+            IntPtr relativePtr = (IntPtr)relative;
+
+            Assert.True(reader.Write(relativePtr, 42, isRelative: true));
+            Assert.Equal(42, reader.Read<int>(absolute));
+        }
+        finally
+        {
+            pin.Free();
+        }
+    }
+
+    [Fact]
+    public void ReadBytes_with_isRelative_true_resolves_correctly()
+    {
+        using var reader = OpenSelf();
+        // DOS header 'MZ' at the image base
+        byte[] data = reader.ReadBytes(IntPtr.Zero, 2, isRelative: true);
+        Assert.Equal(0x4D, data[0]);
+        Assert.Equal(0x5A, data[1]);
+    }
+}