/base/Drivers/S3Trio64/BitmapFileHeader.cs

///////////////////////////////////////////////////////////////////////////////

//

//  Microsoft Research Singularity

//

//  Copyright (c) Microsoft Corporation.  All rights reserved.

//

//  File:    BitmapFileHeader.cs

//

//  Note:

//

#define BUG



using System;

using System.Runtime.InteropServices;



using Microsoft.SingSharp;

using Microsoft.Singularity;

using Microsoft.Singularity.Channels;



namespace Microsoft.Singularity.Io

{

#if BUG

    [CLSCompliant(false)]

    [StructLayout(LayoutKind.Explicit)]

    public pointerfree struct BITMAPFILEHEADER {

        [FieldOffset( 0)] public ushort bfType;

        [FieldOffset( 2)] public uint bfSize;

        [FieldOffset( 6)] public ushort bfReserved1;

        [FieldOffset( 8)] public ushort bfReserved2;

        [FieldOffset(10)] public int bfOffBits;

#else

    [CLSCompliant(false)]

    [StructLayout(LayoutKind.Sequential, Pack=2)]

    public pointerfree struct BITMAPFILEHEADER {

        public ushort bfType;

        public uint bfSize;

        public ushort bfReserved1;

        public ushort bfReserved2;

        public int bfOffBits;

#endif



        public static BITMAPFILEHEADER Read(byte[]! in ExHeap buffer,

                                            int offset, out int used)

        {

            if (buffer == null || offset < 0 ||

                offset + sizeof(BITMAPFILEHEADER) > buffer.Length) {

                unchecked {

                    Tracing.Log(Tracing.Error,

                                "BITMAPFILEHEADER Read(offset={0}, length={1})",

                                (UIntPtr)(uint)offset,

                                (UIntPtr)(uint)buffer.Length);

                }

                throw new OverflowException("Read source invalid.");

            }



            used = offset + /*sizeof(BITMAPFILEHEADER)*/ 14;



            ref BITMAPFILEHEADER bmfh = ref buffer[offset];

            return bmfh;

        }

    }

} // namespace Microsoft.Singularity.Io