// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using CoreFXTestLibrary;

public struct someStruct
{
    public bool p;
    private int var;
}

[StructLayout(LayoutKind.Explicit)]
public class MySystemTime
{
    [FieldOffset(0)]
    public ushort wYear;
    [FieldOffset(2)]
    public ushort wMonth;
    [FieldOffset(4)]
    public ushort wDayOfWeek;
    [FieldOffset(6)]
    public ushort wDay;
    [FieldOffset(8)]
    public ushort wHour;
    [FieldOffset(10)]
    public ushort wMinute;
    [FieldOffset(12)]
    public ushort wSecond;
    [FieldOffset(14)]
    public ushort wMilliseconds;
}

[StructLayout(LayoutKind.Sequential)]
public class MyPoint
{
    public int x;
    public int y;
}

public class NoLayoutPoint
{
    public int x;
    public int y;
}

[StructLayout(LayoutKind.Sequential)]
public class NonExistField
{

}

[StructLayout(LayoutKind.Explicit)]
internal struct ExplicitLayoutTest
{
    [FieldOffset(0)]
    public short m_short1; // 2 bytes
    [FieldOffset(2)]
    public short m_short2; // 2 bytes

    [FieldOffset(4)]
    public byte union1_byte1; // 1 byte
    [FieldOffset(5)]
    public byte union1_byte2; // 1 byte
    [FieldOffset(6)]
    public short union1_short1; // 2 bytes
    [FieldOffset(8)]
    public Int32 union1_int1; // 4 bytes
    [FieldOffset(12)]
    public Int32 union1_int2; // 4 bytes
    [FieldOffset(16)]
    public double union1_double1; // 8 bytes

    [FieldOffset(4)]
    public ushort union2_ushort1; // 2 bytes
    [FieldOffset(6)]
    public ushort union2_ushort2; // 2 bytes
    [FieldOffset(8)]
    public Int32 union3_int1; // 4 bytes
    [FieldOffset(8)]
    public decimal union3_decimal1; // 16 bytes

    [FieldOffset(24)]
    public ushort m_ushort1; // 2 bytes
    // 6 bytes of padding

    [FieldOffset(32)]
    public decimal m_decimal1; // 16 bytes

    [FieldOffset(48)]
    public char m_char1; // 1 byte
    // 7 bytes of padding
}

internal struct FieldAlignementTest
{
    public byte m_byte1; // 1 byte
    // 1 byte of padding

    public short m_short1; // 2 bytes
    public short m_short2; // 2 bytes
    // 2 bytes of padding

    public Int32 m_int1; // 4 bytes
    public byte m_byte2; // 1 byte
    // 3 bytes of padding

    public Int32 m_int2; // 4 bytes
    // 4 bytes of padding

    public double m_double1; // 8 bytes
    public char m_char1; // 1 byte
    public char m_char2; // 1 byte
    public char m_char3; // 1 byte
    // 5 bytes of padding

    public double m_double2; // 8 bytes
    public byte m_byte3; // 1 byte
    public byte m_byte4; // 1 byte
    // 6 bytes of padding

    public decimal m_decimal1; // 16 bytes
    public char m_char4; // 1 byte
    // 7 bytes of padding
}

struct FieldAlignementTest_Decimal
{
    public byte b; // 1 byte
    // 7 bytes of padding

    // The largest field in below struct is decimal (16 bytes wide).
    // However, alignment requirement for the below struct should be only  8 bytes (not 16).
    // This is because unlike fields of other types well known to mcg (like long, char etc.)
    // which need to be aligned according to their byte size, decimal is really a struct
    // with 8 byte alignment requirement.
    public FieldAlignementTest p; // 80 bytes

    public short s; // 2 bytes
    // 6 bytes of padding
}

struct FieldAlignementTest_Guid
{
    public byte b; // 1 byte
    // 3 bytes of padding

    // Guid is really a struct with 4 byte alignment requirement (which is less than its byte size of 16 bytes).
    public Guid g; // 16 bytes

    public short s; // 2 bytes
    // 2 bytes of padding
}

struct FieldAlignementTest_Variant
{
    public byte b; // 1 byte
    // 7 bytes of padding

    // Using [MarshalAs(UnmanagedType.Struct)] means that the Variant type will be used for field 'v' on native side.
    // Variant is really a struct with 8 byte alignment requirement (which is less than its byte size of 24 / 16 bytes).
    [MarshalAs(UnmanagedType.Struct)]
    public object v; // 16 bytes on 32-bit, 24 bytes on 64-bit

    public short s; // 2 bytes
    // 6 bytes of padding
};

public class OffsetTest
{
    
    public static void NullParameter()
    {
        Assert.Throws<ArgumentNullException>(() => Marshal.OffsetOf(null, null));
        Assert.Throws<ArgumentNullException>(() => Marshal.OffsetOf(new object().GetType(), null));
        Assert.Throws<ArgumentNullException>(() => Marshal.OffsetOf(null, "abcd"));
    }

    
    public static void NonExistField()
    {
        Assert.Throws<ArgumentException>(() => Marshal.OffsetOf(typeof(NonExistField), "NonExistField"));
    }

    
    public static void NoLayoutClass()
    {
        Assert.Throws<ArgumentException>(() => Marshal.OffsetOf(typeof(NoLayoutPoint), "x"));
    }

    
    public static void StructField()
    {
        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(typeof(someStruct), "var"));
    }

    
    public static void ClassExplicitField()
    {
        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(typeof(MySystemTime), "wYear"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(typeof(MySystemTime), "wHour"));
        Assert.AreEqual(new IntPtr(14), Marshal.OffsetOf(typeof(MySystemTime), "wMilliseconds"));
    }

    
    public static void ClassSequentialField()
    {
        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(typeof(MyPoint), "x"));
        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(typeof(MyPoint), "y"));
    }

    
    public static void ProjectedType()
    {
#if BUG_1212387        
        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(typeof(Windows.Foundation.Point), "_x"));
        Assert.AreEqual(new IntPtr(1), Marshal.OffsetOf(typeof(Windows.UI.Color), "_R"));
#endif        
    }


    
    public static void TestExplicitLayout()
    {
        var t = typeof(ExplicitLayoutTest);
        Assert.AreEqual(56, Marshal.SizeOf(t));
        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(t, "m_short1"));
        Assert.AreEqual(new IntPtr(2), Marshal.OffsetOf(t, "m_short2"));

        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(t, "union1_byte1"));
        Assert.AreEqual(new IntPtr(5), Marshal.OffsetOf(t, "union1_byte2"));
        Assert.AreEqual(new IntPtr(6), Marshal.OffsetOf(t, "union1_short1"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "union1_int1"));
        Assert.AreEqual(new IntPtr(12), Marshal.OffsetOf(t, "union1_int2"));
        Assert.AreEqual(new IntPtr(16), Marshal.OffsetOf(t, "union1_double1"));

        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(t, "union2_ushort1"));
        Assert.AreEqual(new IntPtr(6), Marshal.OffsetOf(t, "union2_ushort2"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "union3_int1"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "union3_decimal1"));

        Assert.AreEqual(new IntPtr(24), Marshal.OffsetOf(t, "m_ushort1"));
        Assert.AreEqual(new IntPtr(32), Marshal.OffsetOf(t, "m_decimal1"));
        Assert.AreEqual(new IntPtr(48), Marshal.OffsetOf(t, "m_char1"));
    }

    
    public static void TestFieldAlignment()
    {
        var t = typeof(FieldAlignementTest);
        Assert.AreEqual(80, Marshal.SizeOf(t));

        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(t, "m_byte1"));
        Assert.AreEqual(new IntPtr(2), Marshal.OffsetOf(t, "m_short1"));
        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(t, "m_short2"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "m_int1"));
        Assert.AreEqual(new IntPtr(12), Marshal.OffsetOf(t, "m_byte2"));
        Assert.AreEqual(new IntPtr(16), Marshal.OffsetOf(t, "m_int2"));
        Assert.AreEqual(new IntPtr(24), Marshal.OffsetOf(t, "m_double1"));
        Assert.AreEqual(new IntPtr(32), Marshal.OffsetOf(t, "m_char1"));
        Assert.AreEqual(new IntPtr(33), Marshal.OffsetOf(t, "m_char2"));
        Assert.AreEqual(new IntPtr(34), Marshal.OffsetOf(t, "m_char3"));
        Assert.AreEqual(new IntPtr(40), Marshal.OffsetOf(t, "m_double2"));
        Assert.AreEqual(new IntPtr(48), Marshal.OffsetOf(t, "m_byte3"));
        Assert.AreEqual(new IntPtr(49), Marshal.OffsetOf(t, "m_byte4"));
        Assert.AreEqual(new IntPtr(56), Marshal.OffsetOf(t, "m_decimal1"));
        Assert.AreEqual(new IntPtr(72), Marshal.OffsetOf(t, "m_char4"));
    }

    
    public static void TestFieldAlignment_Decimal()
    {
        var t = typeof(FieldAlignementTest_Decimal);
        Assert.AreEqual(96, Marshal.SizeOf(t));

        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(t, "b"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "p"));
        Assert.AreEqual(new IntPtr(88), Marshal.OffsetOf(t, "s"));
    }

    
    public static void TestFieldAlignment_Guid()
    {
        var t = typeof(FieldAlignementTest_Guid);
        Assert.AreEqual(24, Marshal.SizeOf(t));

        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(t, "b"));
        Assert.AreEqual(new IntPtr(4), Marshal.OffsetOf(t, "g"));
        Assert.AreEqual(new IntPtr(20), Marshal.OffsetOf(t, "s"));
    }

    
    public static void TestFieldAlignment_Variant()
    {
        var t = typeof(FieldAlignementTest_Variant);

        Assert.AreEqual(new IntPtr(0), Marshal.OffsetOf(t, "b"));
        Assert.AreEqual(new IntPtr(8), Marshal.OffsetOf(t, "v"));

        if (IntPtr.Size == 4)
        {
            Assert.AreEqual(new IntPtr(24), Marshal.OffsetOf(t, "s"));
            Assert.AreEqual(32, Marshal.SizeOf(t));
        }
        else if (IntPtr.Size == 8)
        {
            Assert.AreEqual(new IntPtr(32), Marshal.OffsetOf(t, "s"));
            Assert.AreEqual(40, Marshal.SizeOf(t));
        }
        else
        {
            Assert.Fail(string.Format("Unexpected value '{0}' for IntPtr.Size", IntPtr.Size));
        }
    }

    public static int Main(String[] args)
    {
        //https://github.com/dotnet/coreclr/issues/2075  
        //TestFieldAlignment_Variant();
        TestFieldAlignment_Guid();
        TestFieldAlignment_Decimal();
        TestFieldAlignment();
        TestExplicitLayout();
        ClassSequentialField();
        NullParameter();
        NonExistField();
        NoLayoutClass();
        StructField();
        ClassExplicitField();
        return 100;
    }
}