sylpheed-port reports that a record's loop length is on no public ref at all
(example, test and docs/re/ only), so their screen.rs parses the four bytes with
its own RATC guard. That is my field to publish.
One function serves both levels, since a nested .rat leaf is itself a RATC bundle
with the same header shape. Returns None for a non-RATC or short slice so callers
need no guard of their own.
Verified against the disc, controls first: rejects a non-RATC slice, rejects one
too short for the field, reads big-endian at +0x08 -- then reproduces every
published value (ptbtn00f 120, ptloop01 600, ptloop02 720) over 65 GP_TITLE
records with 0 violations of +0x08 >= largest keyframe time.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
b5df02a4f7