This is a really great series of articles, and I used a number of the techniques mentioned in them for a program I made - https://www.chinesetextanalyser.com/

The files opened by the program are read-only, so I didn't need to look in to or worry about piece-chains, but it's nice to be able to open multi-gigabyte files, with highlighting, and scroll around instantly to anywhere in the file, and have very low CPU and memory usage.