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https://github.com/ruby/fiddle
A libffi wrapper for Ruby.
https://github.com/ruby/fiddle
fiddle libffi ruby
Last synced: about 1 month ago
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A libffi wrapper for Ruby.
- Host: GitHub
- URL: https://github.com/ruby/fiddle
- Owner: ruby
- License: bsd-2-clause
- Created: 2017-04-05T00:03:38.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2024-09-29T09:25:45.000Z (about 1 month ago)
- Last Synced: 2024-09-29T21:01:20.394Z (about 1 month ago)
- Topics: fiddle, libffi, ruby
- Language: Ruby
- Homepage:
- Size: 579 KB
- Stars: 156
- Watchers: 38
- Forks: 34
- Open Issues: 21
-
Metadata Files:
- Readme: README.md
- Changelog: NEWS.md
- License: LICENSE.txt
Awesome Lists containing this project
README
# Fiddle
[](https://github.com/ruby/fiddle/actions/workflows/ci.yml)
A libffi wrapper for Ruby.
Fiddle is an extension to translate a foreign function interface (FFI) with ruby.
It wraps [libffi](http://sourceware.org/libffi/), a popular C library which provides a portable interface that allows code written in one language to call code written in another language.
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'fiddle'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install fiddle
## Usage
Here we will use Fiddle::Function to wrap [floor(3) from libm](http://linux.die.net/man/3/floor)
```ruby
require 'fiddle'
libm = Fiddle.dlopen('/lib/libm.so.6')
floor = Fiddle::Function.new(
libm['floor'],
[Fiddle::TYPE_DOUBLE],
Fiddle::TYPE_DOUBLE
)
puts floor.call(3.14159) #=> 3.0
```
### Nested Structs
You can use hashes to create nested structs, where the hash keys are member names and the values are the nested structs:
```ruby
StudentCollegeDetail = struct [
'int college_id',
'char college_name[50]'
]
StudentDetail = struct [
'int id',
'char name[20]',
{ clg_data: StudentCollegeDetail }
]
```
You can also specify an anonymous nested struct, like so:
```ruby
StudentDetail = struct [
'int id',
'char name[20]',
{
clg_data: struct([
'int college_id',
'char college_name[50]'
])
}
]
```
The position of a hash (and the order of the keys in the hash, in the case of a hash with multiple entries), dictate the offsets of the nested struct in memory. The following examples are both syntactically valid but will lay out the structs differently in memory:
```ruby
# order of members in memory: position, id, dimensions
Rect = struct [ { position: struct(['float x', 'float y']) },
'int id',
{ dimensions: struct(['float w', 'float h']) }
]
# order of members in memory: id, position, dimensions
Rect = struct [ 'int id',
{
position: struct(['float x', 'float y']),
dimensions: struct(['float w', 'float h'])
}
]
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/fiddle.
## License
The gem is available as open source under the terms of the [BSD-2-Clause](https://opensource.org/licenses/BSD-2-Clause).