/// <summary>
/// Updates a structure that has already been written.
/// </summary>
/// <param name="index">The index of the structure to update</param>
/// <param name="rawStruct">The new data</param>
public void UpdateStruct(uint index, RawGffStruct rawStruct)
{
if (FileAccess.Write != access) throw new InvalidOperationException();
// Make sure that the index is valid.
int size = Marshal.SizeOf(typeof(RawGffStruct));
int count = (int) structsStream.Length / size;
if (index >= count) throw new ArgumentOutOfRangeException();
// Seek to the structure in the stream and update the struct.
structsStream.Seek(index * size, SeekOrigin.Begin);
rawStruct.Serialize(structsStream);
}
/// <summary>
/// Adds a new structure to the end of the structure stream. This method
/// is only valid for write access raw data.
/// </summary>
/// <param name="rawStruct">The structure to add</param>
/// <returns>The index of the addes structure, it is always added to the
/// end of the list</returns>
public uint AddStruct(RawGffStruct rawStruct)
{
if (FileAccess.Write != access) throw new InvalidOperationException();
// Seek to the end of the stream and add the struct.
structsStream.Seek(0, SeekOrigin.End);
rawStruct.Serialize(structsStream);
// Count the number of structs in the stream and return the index of
// the last one, which is the one we just added.
int count = (int) structsStream.Length / Marshal.SizeOf(typeof(RawGffStruct));
return (uint) (count - 1);
}