private long ComputeMagic(long length, FileEnvelopeId id)
{
// HashCodeHelper performs a stable hash code computation.
// We take into account the other header fields, and the file length.
return(HashCodeHelper.Combine(
HashCodeHelper.GetOrdinalHashCode64(m_name),
HashCodeHelper.GetOrdinalHashCode64(id.Value),
Version | (long)(((ulong)(uint)m_version) << 32),
length));
}
