The counted content automaton clamped every occurrence counter to a single
inputLength + 1 ceiling, so a content model with nested occurrence bounds let
the epsilon-closure grow toward inputLength raised to the counter count. The
XSTS particlesQ005 instance (about 1000 elements against
sequence{1,1000}(e1{1,unbounded})) drove that to roughly 16M configurations per
closure and hundreds of millions of hash operations, so validation did not
terminate in reasonable time.
Each counter now saturates at min(maximum, inputLength + 1), and an unbounded
counter at its minimum: once the minimum is reached every higher count is
matching-equivalent, because canExit only tests the minimum and belowMaximum is
vacuous, so collapsing them is exact. The active-configuration set is then
bounded by the content model rather than by the input length.
particlesQ005 goes from a multi-minute near-hang to about two seconds with
identical results. The 1448 unit tests pass and the full XSTS suite still
settles at 0/43/0/31, and now completes instead of hanging.
Mihaela Mihaljevic
73ba9b1f38