1BRC in Swift ( ~ 1.7 Sec on Mac Studio)

[pfy]

I I made a version in swift that runs in ~ 1.7 seconds on a mac studio (the best time observed was 1.633).
The idea is more or less the same as in the other solutions

1. mmap the file
2. split into blocks per core, align to newlines
3. run each block on a core, parse the name first, then the number
   a. while parsing the name, accumulate the hash for the hashtable as well
   b. while parsing, safe the first 8 bytes of the name, since a lot of names are short, we can implement equality for these by a single compare
   c. while parsing the number, save it as int, convert it to float, and divide it by 10 later
4. use a custom hash table, which can use the predefined hash and expose the index, to save some lookups

the code is available on https://github.com/pfy/1brc/tree/main