Local high scores¶

Local score files under scores5/ contain a sequence of independently encoded records. There is no file header. Each record has a 0x48-byte payload followed by a little-endian u32 checksum, for a 0x4c-byte wire record.

For byte index i, encoding adds (i * 5 + 1) * i + 6, modulo 256. The checksum is the sum of (i + 3) * decoded_byte * 7, modulo 2³². Readers skip invalid checksums and ignore an incomplete trailing record.

The name occupies the first 0x20 bytes. Time at offset 0x20 is a signed 32-bit millisecond value: quest bonuses can make it negative. The score field at 0x24 is also compared as a signed native integer. Survival/Typ-o rank by score descending; Rush ranks by time descending; quests rank by time ascending with zero last. Equal scores keep their existing order in the port.

Date bytes at 0x40–0x43 hold day, native dateWeek, month, and year minus 2000. Month/week/day filters use the local calendar and run before the 100-row display limit. The week filter compares the stored native week and year, not Python's ISO week number. Saving a qualifying score retains historical records outside the selected table. Port writes atomically replace the file.

Normal quest files use questhcM_N.hi; hardcore uses questM_N.hi. That apparent inversion is native behavior. The port adds _2, _3, or _4 before .hi for separate local co-op tables. Other modes use survival.hi, rush.hi, and typo.hi.

Names are trimmed in the stored copy before encoding. Native trimming preserves character zero even for an all-space name; the name-entry UI requires a non-space character. A failed score write leaves name entry available for retry.

Implementations: src/crimson/persistence/highscores.py and crimson-zig/src/persistence/highscores.zig. Native evidence is maintained in the highscore_save_record, highscore_load_table, and highscore_compare_* matching sources under tools/match/scratches/.