Parses Section 7.2's uncompressed prefix (counts + block_lengths), growing the read like readHeaderAndDirectory does, since its size depends on country_count/region_counts which aren't known up front.
Parses Section 7.2's uncompressed prefix (counts + block_lengths), growing the read like readHeaderAndDirectory does, since its size depends on country_count/region_counts which aren't known up front.