A compression program targeting PICO-8, based on deflate, with the following characteristics:

• can decompress data from cart RAM, in cart code, or both.
• data is decompressed in Lua memory, allowing for up to 2 MiB of data to exist.
• the p8u decompressor code is optimised for storage size¹.

¹: this is slightly different from optimising for symbol count; p8u could use fewer symbols but at the cost of larger stored size, which is actually less desirable.

The p8z algorithm differs from zlib’s original deflate in the following incompatible ways:

• there is no zlib header or checksum (makes compressed data smaller)
• block headers are smaller (helps reduce decoder code size)
• the algorithm’s bit length code table was simplified (helps reduce decoder code size)
• stored (uncompressed) blocks have no length checksum and are not byte-aligned (makes compressed data smaller)

p8z uses code from zlib and zzlib.