/// <summary>
/// Marshal a managed object to an unmanaged chunk of memory. If <paramref name="structure"/> is not CustomMarshalable this
/// function is the same as <see cref="Marshal.StructureToPtr"/>.
/// </summary>
/// <param name="structure">A managed object to marshal to unmanaged memory.</param>
/// <param name="ptr">Pointer to unmanaged memory. This must be allocated before call</param>
/// <param name="fDeleteOld">Indicates whether to delete old memory first</param>
public static void StructureToPtr(object structure, IntPtr ptr, bool fDeleteOld)
{
if (!IsCustomMarshalObject(structure))
{
Marshal.StructureToPtr(structure, ptr, fDeleteOld);
return;
}
// first check that the struct has the struct layout attribute
StructLayoutAttribute sla = structure.GetType().StructLayoutAttribute;
if (sla.IsDefaultAttribute() || sla.Value == LayoutKind.Auto)
{
throw new ArgumentException("Structure must have StructLayoutAttribute with LayoutKind Explicit or Sequential", "structure");
}
// iterate through all struct fields, handling customs, and using Marshal.StructToPtr for others
uint extraDataOffset = 0;
uint structBase = (uint)ptr.ToInt32();
uint structSize = (uint)Marshal.SizeOf(structure);
foreach (FieldInfo field in structure.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance))
{
uint fieldLoc = structBase + (uint)Marshal.OffsetOf(structure.GetType(), field.Name);
if (field.IsDefined(typeof(CustomMarshalAsAttribute), true))
{
byte[] bytes;
CustomMarshalAsAttribute attr = (CustomMarshalAsAttribute)(field.GetCustomAttributes(typeof(CustomMarshalAsAttribute), true)[0]);
switch (attr.Value)
{
case CustomUnmanagedType.LPStr:
string val = (string)field.GetValue(structure) + '\0';
bytes = Encoding.ASCII.GetBytes(val);
break;
case CustomUnmanagedType.LPWStr:
val = (string)field.GetValue(structure) + '\0';
bytes = Encoding.Unicode.GetBytes(val);
break;
default:
throw new NotSupportedException("Operation not yet supported");
}
uint dataLoc = structBase + structSize + extraDataOffset;
Marshal.WriteIntPtr(new IntPtr(fieldLoc), new IntPtr(dataLoc));
// write the raw bytes to dataLoc
for (int i = 0; i < bytes.Length; i++, extraDataOffset++)
{
Marshal.WriteByte(new IntPtr(dataLoc + (uint)i), bytes[i]);
}
}
else
{
Marshal.StructureToPtr(field.GetValue(structure), new IntPtr(fieldLoc), fDeleteOld);
}
}
}
/// <summary>
/// Marshal an unmanaged to pointer to a managed object. If <paramref name="structureType"/> is not CustomMarshalable, this
/// function is the same as <see cref="Marshal.StructureToPtr"/>.
/// </summary>
/// <param name="ptr">Pointer to unmanaged memory</param>
/// <param name="structureType">Type of managed object to instantiate</param>
/// <returns>Managed instance of <paramref name="structureType"/> type</returns>
public static object PtrToStructure(IntPtr ptr, Type structureType)
{
if (ptr == IntPtr.Zero)
{
return(null);
}
if (structureType == null)
{
throw new ArgumentNullException("structureType");
}
if (structureType.IsGenericType)
{
throw new ArgumentException("Structure type must be non-generic", "structureType");
}
if (!IsCustomMarshalType(structureType))
{
return(Marshal.PtrToStructure(ptr, structureType));
}
StructLayoutAttribute sla = structureType.StructLayoutAttribute;
if (sla.IsDefaultAttribute() || sla.Value == LayoutKind.Auto)
{
throw new ArgumentException("Structure must have StructLayoutAttribute with LayoutKind Explicit or Sequential", "structure");
}
object structure = Activator.CreateInstance(structureType);
uint structBase = (uint)ptr.ToInt32();
uint structSize = (uint)Marshal.SizeOf(structure);
foreach (FieldInfo field in structureType.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance))
{
uint fieldLoc = structBase + (uint)Marshal.OffsetOf(structureType, field.Name);
if (field.IsDefined(typeof(CustomMarshalAsAttribute), true))
{
IntPtr extraDataLoc = Marshal.ReadIntPtr(new IntPtr(fieldLoc));
CustomMarshalAsAttribute attr = (CustomMarshalAsAttribute)(field.GetCustomAttributes(typeof(CustomMarshalAsAttribute), true)[0]);
switch (attr.Value)
{
case CustomUnmanagedType.LPStr:
field.SetValue(structure, Marshal.PtrToStringAnsi(extraDataLoc));
break;
case CustomUnmanagedType.LPWStr:
field.SetValue(structure, Marshal.PtrToStringUni(extraDataLoc));
break;
default:
throw new NotSupportedException("Operation not currently supported");
}
}
else
{
field.SetValue(structure, Marshal.PtrToStructure(new IntPtr(fieldLoc), field.FieldType));
}
}
return(structure);
}