Bitfield for up to 64bits in length
Package bitfield64 is a simple, quick stack-based bit-field manipulator package of 64 bits (or less) in length. If you need more bits you either need to create an array of bitfield64-s (and stay on the stack) or need to switch to the heap-based bitfield package.
Methods are stateless and free from side-effects.
It was designed to be chainable. Range for position must be [0, 63]. position outside this range will get the modulo treatment, so 64 will point to the 0th element, -1 will address the last element (i.e. 63rd), -2 the one before (i.e. 62nd), etc.
For usage see test file.