static SafeHGlobalHandle AllocHGlobal(int cb)
{
if (cb < 0)
{
throw new ArgumentOutOfRangeException(nameof(cb), "The value of this argument must be non-negative");
}
var result = new SafeHGlobalHandle();
//
// CER
//
RuntimeHelpers.PrepareConstrainedRegions();
result._pointer = Marshal.AllocHGlobal(cb);
return(result);
}
/// <summary>
/// Allocates from unmanaged memory to represent a structure with a
/// variable length array at the end and marshal these structure
/// elements. It is the callers responsibility to marshal what preceeds
/// the trailinh array into the unmanaged memory. ONLY structures with
/// attribute StructLayout of LayoutKind.Sequential are supported.
/// </summary>
/// <typeparam name="T">Type of the trailing array of structures</typeparam>
/// <param name="prefixBytes">Number of bytes preceeding the trailing array of structures</param>
/// <param name="values">Collection of structure objects</param>
/// <param name="count"></param>
/// <returns>SafeHGlobalHandle object to an native (unmanaged) structure
/// with a trail array of structures</returns>
public static SafeHGlobalHandle AllocHGlobal <T>(int prefixBytes, IEnumerable <T> values, int count) where T
: struct
{
var structLayoutAttribute = typeof(T).StructLayoutAttribute;
Debug.Assert(structLayoutAttribute != null && structLayoutAttribute.Value == LayoutKind.Sequential);
SafeHGlobalHandle result = AllocHGlobal(prefixBytes + Marshal.SizeOf(typeof(T)) * count);
IntPtr ptr = result._pointer + prefixBytes;
foreach (var value in values)
{
Marshal.StructureToPtr(value, ptr, false);
ptr += Marshal.SizeOf(typeof(T));
}
return(result);
}