GSMEncoder encodes and decodes Ruby Strings to and from the SMS default alphabet. It also supports the default extension table. The default alphabet and it's extension table is defined in GSM 03.38

This is port of Twitter's Java implementation

NOTE: ruby >= 1.9.2 is required

gem install gsm_encoder

require 'gsm_encoder'

# encoding
GSMEncoder.encode 'hello @ world' # => binary string

# decoding
GSMEncoder.decode(GSMEncoder.encode('hi')) # => 'hi'

# can encode?
GSMEncoder.can_encode?('`') # => false

# replaces unsupported chars with '?'
GSMEncoder.encode('`') # => '?'

# replaces unsupported chars with a provided value ' '
GSMEncoder.encode('`', ' ') # => ' '

Added support for Spanish shift

Fixed bug when encoding line feed & carriage return

Adds the ability to provide the character used when encoding unsupported strings

Code cleanup and speedup

Even faster. About 4 times. Many thanks to @dlarrabee