pub fn parse_source_header(content: &[u8]) -> Option<SourceHeader>Expand description
Parse the HEADER section of content.
Returns None when no recognisable header record is present (a non-STEP
input), which is the caller’s signal to fall back to its own defaults rather
than to write empty fields. Cheap: only the first MAX_HEADER_BYTES are
examined, truncated at the first ENDSEC so DATA is never scanned.