I'm struggling with this one. I'm getting these errors exclusively in the app I'm trying to use it with:

(gdb) backtrace
#0 0x00007fff81f63616 in __kill ()
#1 0x00007fff82003cca in abort ()
#2 0x00007fff81f1b6f5 in free ()
#3 0x00000001007b855a in bitset_free (bs=0x10756b280) at bitset.c:28
#4 0x000000010003aead in run_final (obj=4384258840) at gc.c:1955
#5 0x000000010003aede in finalize_list (p=0x105527b18) at gc.c:1097

...

I've been starting at the code for an hour and bashing it from every angle, but it refuses to die under any spec I write.

Any ideas?

As of 2/23/2016, this version no longer builds on the latest Ruby, and it has a couple bugs I am aware of. I invite people to use my version at https://github.com/ericboesch/bitset . Thanks again to Tyler for creating this!

b = Bitset.new(16000)
[5343, 15661, 1500, 6225].each {|i| b[i] = true }
b.to_s.count("1") # => 8 (instead of 4)
b.cardinality # => 36 (instead of 4)
(0...16000).select{|x| b[x]} # => [1500, 1532, 5343, 5375, 6225, 6257, 15629, 15661]

If you have a Bitset of size 64, you get an incorrect cardinality value (always 0).

bits = Bitset.new(64)
bits.set(13,23)
puts bits.cardinality

Results in the value of 0, when it should be 2.

a = Bitset.new(7)
b = ~Bitset.new(7)
a.hamming(b) #=> 64

The problem is that internally the representation is always some number of 64-bit integers, and so unless we explicitly mask out the bits that exist above the actual content bits, it's easy for them to affect operations.

I would like to see bit shifting operators supported (>> and <<)