fc-solve-support-for-delta-states-planning.txt

Motivation:
-----------

This document will describe how we are planning to add support for delta
states (current "delta_states.c" in the Freecell Solver distribution) to
the main libfreecell-solver library, and how it will be implemented.

---------------

Encoded states will be stored instead of the currently decoded states in:

1. The states collection (the hash or tree used to store all traversed or
encountered states) - handled by check_and_add_state.c

2. In the Random-DFS stack, the Breadth-First-Search queue, and the
Best-First-Search priority queue.

The data type of a possibly encoded state will be fcs_stored_state_t which
will be an encoded state for FCS_DELTA_STATES and an unencoded state if
FCS_DELTA_STATES is off.

We will define two macros/inline-functions:

fcs_state_stored_to_expanded
fcs_state_expanded_to_stored