Dump load

[yegct]

What

This PR allows BitArray to be dumped to disk and subsequently loaded from disk. It also adds the ability to union two bitarrays. And there's a new class, BitArrayFile, allowing for read-only access to a dumped BitArray, providing a means to query the array without having to load it in to RAM.

Tests

$ ruby test/test_bit_array.rb 
Run options: --seed 52069

# Running:

.................

Finished in 0.007989s, 2127.8684 runs/s, 527461.0175 assertions/s.

17 runs, 4214 assertions, 0 failures, 0 errors, 0 skips


$ ruby test/test_bit_array_file.rb 
Run options: --seed 36015

# Running:

....

Finished in 0.003689s, 1084.2876 runs/s, 37950.0675 assertions/s.

4 runs, 140 assertions, 0 failures, 0 errors, 0 skips

Additionally, I tested this with a bitarray consisting of a little over 2 billion bits. I was able to dump, load, and use BitArrayFile to query the bits.

[yegct]

Changed from 1.3.0.

[yegct]

We don't use this here, but need it for BitArrayFile.

[yegct]

Added the ability to compare two BitArray objects. This makes it a bit easier to add tests.

[yegct]

I wrote this because it allows parallelising bloom filter creation. I don't personally need this method, but figured it might be useful for others.

[yegct]

The following two methods, dump and load, are new.

[yegct]

It's actually fairly easy to implement the rest of BitArray, allowing this to be read/write instead of read-only. But it's quite a bit slower, at least for large bitarrays and nobody's likely to care for small bitarrays. Seemed to be unnecessary bloat.

[yegct]

Note that I'm more familiar with rspec. Please excuse me if these tests aren't how most people would write Minitest tests.

[peterc]

In a way, Minitest is to RSpec as Sinatra is to Rails. Minitest is far less opinionated and freeform which has upsides and downsides, but a big upside is pretty much any approach that works and fits into a project's own style is all good! :)

[peterc]

I've merged the previous one but this will take a little bit more review - thanks for now though!

[yegct]

I've merged the previous one but this will take a little bit more review - thanks for now though!

Rebased off of main. If you don't like/want the union, let me know and I'll drop that (and associated tests). If you want me to do some cleanup, happy to do that too.