rust-csv

It's extremely simple. Even if you don't know Rust, this code should be readable: https://github.com/BurntSushi/rust-csv/blob/master/src/index... Basically, it writes a 64 bit byte offset (big endian) for the start of each record. The very last byte is then the total number of records. (I forget why I'm doing this, since the count should be computable from the size of the index file.) The "start of each record" means "if you point a CSV parser at this byte offset, then it will successfully read a record." So when you want to read record `i`, seek the index to byte offset `i * 8`, read 8 bytes (big endian) into a 64 bit integer, then seek to that byte offset in your CSV data. If the CSV data changes, then you're in trouble. One easy way to handle it (which isn't bulletproof) is to check the last modified times of the index and the CSV file

Looks like it's based on this CSV parser: https://github.com/BurntSushi/rust-csv and it claims to be RFC4180-compliant, which is a good thing.

CSV parsing: https://github.com/BurntSushi/rust-csv Arg parsing: https://github.com/docopt/docopt.rs