README.md
# Kmp
[](https://travis-ci.org/tanvir002700/kmp)
[](https://codeclimate.com/github/tanvir002700/kmp/maintainability)
[](https://coveralls.io/github/tanvir002700/kmp?branch=master)
[](https://badge.fury.io/rb/kmp)
[](https://rubygems.org/gems/kmp)
[](https://github.com/tanvir002700/kmp)
[](https://github.com/tanvir002700/kmp/blob/master/LICENSE)
This gem is KMP (Knuth–Morris–Pratt algorithm) implemantation with c Extension.
A super first substring find technique in a big string.
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'kmp'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install kmp
## Usage
``` ruby
require 'kmp'
k = Kmp::String.new 'abcdeab'
k.match 'ab' #=> [0, 5]
k.length #=> 7
k.replace 'ab', 'X' #=> 'XcdeX'
```
## Complexity
- match function complexity O(N+M), N original text string length, M match string length
- replace function complexity O(N+M)
- length complexity O(1)
## Benchmark
This benchmark between kmp implementation in c-extenstion vs pure ruby. [Benchmark](http://ruby-doc.org/stdlib-2.0.0/libdoc/benchmark/rdoc/Benchmark.html) module use for comparison.
```
lenght of string: 500
Rehearsal -----------------------------------------------
c-extension 0.000000 0.000000 0.000000 ( 0.000028)
ruby 0.000000 0.000000 0.000000 ( 0.001067)
-------------------------------------- total: 0.000000sec
user system total real
c-extension 0.000000 0.000000 0.000000 ( 0.000019)
ruby 0.000000 0.000000 0.000000 ( 0.000731)
lenght of string: 5000
Rehearsal -----------------------------------------------
c-extension 0.000000 0.000000 0.000000 ( 0.000074)
ruby 0.000000 0.000000 0.000000 ( 0.006990)
-------------------------------------- total: 0.000000sec
user system total real
c-extension 0.000000 0.000000 0.000000 ( 0.000059)
ruby 0.000000 0.000000 0.000000 ( 0.003058)
lenght of string: 50000
Rehearsal -----------------------------------------------
c-extension 0.000000 0.000000 0.000000 ( 0.000276)
ruby 0.030000 0.000000 0.030000 ( 0.022061)
-------------------------------------- total: 0.030000sec
user system total real
c-extension 0.000000 0.000000 0.000000 ( 0.000117)
ruby 0.010000 0.000000 0.010000 ( 0.014624)
lenght of string: 500000
Rehearsal -----------------------------------------------
c-extension 0.000000 0.000000 0.000000 ( 0.001346)
ruby 0.140000 0.000000 0.140000 ( 0.147500)
-------------------------------------- total: 0.140000sec
user system total real
c-extension 0.000000 0.000000 0.000000 ( 0.001188)
ruby 0.140000 0.000000 0.140000 ( 0.146642)
lenght of string: 5000000
Rehearsal -----------------------------------------------
c-extension 0.010000 0.000000 0.010000 ( 0.013171)
ruby 1.480000 0.010000 1.490000 ( 1.482893)
-------------------------------------- total: 1.500000sec
user system total real
c-extension 0.010000 0.000000 0.010000 ( 0.013098)
ruby 1.510000 0.000000 1.510000 ( 1.508361)
lenght of string: 50000000
Rehearsal -----------------------------------------------
c-extension 0.120000 0.020000 0.140000 ( 0.143160)
ruby 16.320000 0.020000 16.340000 ( 16.356332)
------------------------------------- total: 16.480000sec
user system total real
c-extension 0.120000 0.010000 0.130000 ( 0.143203)
ruby 15.130000 0.050000 15.180000 ( 15.191924)
lenght of string: 500000000
Rehearsal -----------------------------------------------
c-extension 1.190000 0.200000 1.390000 ( 1.491211)
ruby 159.510000 0.210000 159.720000 (159.723059)
------------------------------------ total: 161.110000sec
user system total real
c-extension 1.270000 0.200000 1.470000 ( 1.568321)
ruby 161.190000 0.250000 161.440000 (161.449839)
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment. For compile c extension run `rake compile`.
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/tanvir002700/kmp. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.
## License
The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
## Code of Conduct
Everyone interacting in the Kmp project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/tanvir002700/kmp/blob/master/CODE_OF_CONDUCT.md).