Welcome to Data Crystal's new home! Data Crystal is now part of the TCRF family (sort of).
The wiki has recently moved; please report any issues in Discord. Pardon the dust.
The wiki has recently moved; please report any issues in Discord. Pardon the dust.
Sega Ages 2500 Series Vol. 17: Phantasy Star generation:2/Notes
Jump to navigation
Jump to search
Compression
CUE found out the coding algorithm. It's a Lempel-Ziv related one, called Lempel-Ziv Renau.
Structure of files :
- Bytes $0000 to $000a : header
- 2 bytes : signature, always "CM"
- 4 bytes: decoded data length, low endian
- 4 bytes: encoded data length, low endian
- From $000a : ENCODED_DATA
- Then FLAGS. Flags are read bit per bit :
- if bit = 0, then put one byte from ENCODED_DATA and put into DECODED_STREAM
- if bit = 1, then the corresponding half-word in ENCODED_DATA is of the form lllloooooooooooo, where l = length and o = offset. Copy then 'length + 3' bytes from DECODED_STREAM[current_position - offset + 1] to DECODED_STREAM[curent_position].
- Fill the file with $00, up to have a file size dividible by $800.