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bitarray

(★ 107)

Pure Ruby bit array/bitfield implementation

파일 탐색기

최종 버전 다운로드 (.zip)

- - bit_array.rb
- bitarray.rb
- test_bit_array.rb
.gitignore
bitarray.gemspec
Gemfile
LICENSE
memory-test.rb
Rakefile
README.md

# 설치 가이드

1. 코드 내려받기

git clone https://github.com/peterc/bitarray

깃허브에서 프로젝트 코드 전체를 내 컴퓨터로 내려받습니다.

cd bitarray

방금 내려받은 프로젝트 폴더 안으로 이동합니다.

2. Ruby

쉬움 추천

사전 준비물

Git GitHub에서 프로젝트 코드를 내려받으려면 필요합니다.
Ruby bundle 명령어를 쓰려면 Ruby가 필요합니다.

bundle add bitarray

이 명령어를 터미널에 그대로 입력해 실행하세요.

✅ bundle install이 에러 없이 끝나면 README에 안내된 실행 명령어(예: rails server)로 마저 실행해보세요.

이 레포의 README에 적힌 실제 명령어를 그대로 가져왔습니다.

// repository documentation

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# BitArray: Pure Ruby bit-array/bitfield library

A simple, pure-Ruby 'bit field' object.

Originally built to help power a bloom filter, although there are other higher level libraries for that task now (https://github.com/igrigorik/bloomfilter-rb is a popular one.)

BitArray has changed little over the years, but has been maintained to work within a typical, modern Ruby environment and works with Ruby 2.1+ through Ruby 3.x.

## Installation

```ruby
bundle add bitarray
```

## Examples

To use:

```ruby
require 'bitarray'
```

Create a bit array 1000 bits wide:

```ruby
ba = BitArray.new(1000)
```

Setting and reading bits:

```ruby
ba[100] = 1
ba[100]
#=> 1

ba[100] = 0
ba[100]
#=> 0
```

More:

```ruby
ba = BitArray.new(20)
[1,3,5,9,11,13,15].each { |i| ba[i] = 1 }
ba.to_s
#=> "01010100010101010000"
ba.total_set
#=> 7
```

Initializing `BitArray` with a custom field value:

```ruby
ba = BitArray.new(16, ["0000111111110000"].pack('B*'))
ba.to_s # "1111000000001111"
```

`BitArray` by default stores the bits in reverse order for each byte. If for example, you are initializing `BitArray` with Redis raw value manipulated with `setbit` / `getbit` operations, you will need to tell `BitArray` to not reverse the bits in each byte using the `reverse_byte: false` option:

```ruby
ba = BitArray.new(16, ["0000111111110000"].pack('B*'), reverse_byte: false)
ba.to_s # "0000111111110000"
```

## History
- 1.3.2 in 2026 (minor cleanup, faster total_set)
- 1.3.1 in 2024 (no changes other than adding license to gemspec)
- 1.3 in 2022 (cleanups and a minor perf tweak)
- 1.2 in 2018 (Added option to skip reverse the bits for each byte by @dalibor)
- 1.1 in 2018 (fixed a significant bug)
- 1.0 in 2017 (updated for modern Ruby, more efficient storage, and 10th birthday)
- 0.0.1 in 2012 (original v5 released on GitHub)
- v5 (added support for flags being on by default, instead of off)
- v4 (fixed bug where setting 0 bits to 0 caused a set to 1)
- v3 (supports dynamic bitwidths for array elements.. now doing 32 bit widths default)
- v2 (now uses 1 << y, rather than 2 ** y .. it's 21.8 times faster!)
- v1 (first release)

## Thanks

Thanks to Michael Slade for encouraging me to update this library on its 10th birthday and for suggesting finally using String's getbyte and setbyte methods now that we're all on 1.9+ compatible implementations.

Further thanks to @tdeo, @JoshuaSP, @dalibor, @yegct and @m1lt0n for pull requests.

## License

MIT licensed. Copyright 2007-2026 Peter Cooper.