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+# br-cnpj ![travis-ci build status](https://secure.travis-ci.org/bbcoimbra/br-cnpj.png?branch=master)
+
+Ruby native extension that calculates and validades CNPJ (Cadastro Nacional de
+Pessoas Jurídicas)
+
+## Install
+
+```bash
+sudo gem install br-cnpj
+```
+
+## Examples
+
+```ruby
+require 'rubygems'
+require 'br/cnpj'
+
+BR::CNPJ.valid? '00000000000191'
+ #> true
+
+BR::CNPJ.valid? 191
+ #> true
+
+BR::CNPJ.valid? 192
+ #> false
+
+radix = 0
+filial = 1
+BR::CNPJ.new(radix, filial).to_s
+ #> '00000000000191'
+
+BR::CNPJ.new(191).valid?
+ #> true
+
+BR::CNPJ.new(1234567891011).valid?
+ #> false
+
+BR::CNPJ.format(191)
+ #> '00.000.000/0001-91'
+
+BR::CNPJ.unformat('00.000.000/0001-91')
+ #> '00000000000191'
+```
+
+## Copyright
+
+Copyright (c) 2010 Bruno Coimbra. Veja o arquivo LICENSE para mais detalhes.