/// <summary>Marshals data from a managed object to an unmanaged block of memory that is allocated using <paramref name="memAlloc"/>.</summary>
/// <typeparam name="T">The type of the managed object.</typeparam>
/// <param name="value">
/// A managed object that holds the data to be marshaled. The object must be a structure or an instance of a formatted class.
/// </param>
/// <param name="memAlloc">
/// The function that allocates the memory for the structure (typically <see cref="Marshal.AllocCoTaskMem(int)"/> or <see cref="Marshal.AllocHGlobal(int)"/>.
/// </param>
/// <param name="bytesAllocated">The bytes allocated by the <paramref name="memAlloc"/> method.</param>
/// <param name="prefixBytes">Number of bytes preceding the trailing strings.</param>
/// <returns>A pointer to the memory allocated by <paramref name="memAlloc"/>.</returns>
public static IntPtr MarshalToPtr <T>(this T value, Func <int, IntPtr> memAlloc, out int bytesAllocated, int prefixBytes = 0)
{
if (VanaraMarshaler.CanMarshal(typeof(T), out var marshaler))
{
using var mem = marshaler.MarshalManagedToNative(value);
var ret = memAlloc(bytesAllocated = mem.Size + prefixBytes);
mem.DangerousGetHandle().CopyTo(ret.Offset(prefixBytes), mem.Size);
return(ret);
}
else
{
var newVal = TrueValue(value, out bytesAllocated);
bytesAllocated += prefixBytes;
var ret = memAlloc(bytesAllocated);
Write(ret, newVal, prefixBytes, bytesAllocated);
return(ret);
}
}
/// <summary>Determines whether this type is marshalable.</summary>
/// <param name="type">The type to check.</param>
/// <returns><see langword="true"/> if the specified type is marshalable; otherwise, <see langword="false"/>.</returns>
public static bool IsMarshalable(this Type type)
{
var t = type.IsNullable() ? type.GetGenericArguments()[0] : type;
return(t.IsSerializable || VanaraMarshaler.CanMarshal(t, out _) || t.IsBlittable());
}
