gsm_texting

GSM-7 is a character encoding standard which packs the most commonly used letters and symbols in many languages into 7 bits each for usage on GSM networks.
As SMS messages are transmitted 140 8-bit octets at a time, GSM-7 encoded SMS messages can carry up to 160 characters.

Unfortunately, GSM-7 is not a supported character encoding in many text editors. Even setting encoding to ASCII (or US_ASCII, or UTF-8) will not guarantee that text you write will be limited to GSM-7.

If you are writing in an editor with Unicode support you'll need to be particularly careful. Text editors designed for writing might automatically add angled smart quotes, non-standard spaces, or punctuation which looks similar to GSM-7 but is a different Unicode character.

When messages include 1 or more non-GSM characters they will be limited to 70 characters as Unicode chars require 16 bits each.

This lib will transliterate your text to GSM-7 compatible chars so you can send as much characters as possible into a single SMS segment.

Resources: https://en.wikipedia.org/wiki/GSM_03.38 https://www.twilio.com/docs/glossary/what-is-gsm-7-character-encoding https://www.twilio.com/docs/sms/services/smart-encoding-char-list

methods

# Checks if a string can be encoded in GSM-7
def can_encode?(str); end

# Encodes string in GSM-7 characters
#
# :replace_char, use this char as replacement for those characters that cannot
# be encoded. If none is provied, "?" will be used.
#
# :transliterate, if true characters with accents, cedilla and other unique
# attributes will be transformed to a GSM-7 compatible char that look alike
#
# :truncate, if true, string will be truncated to fit in a single SMS Segment 
def encode(str, replace_char: nil, transliterate: false, truncate: false); end

# Returns true if string can be encoded in GSM-7 and fits in a single segment.
def single_segment?(str); end 

usage

require 'gsm_texting'
GSMTexting.can_encode?("àáàáèéìíòóùú") 
=> false

GSMTexting.encode("àáàáèéìíòóùú")
=> "à?à?èéì?ò?ù?"

GSMTexting.encode("àáàáèéìíòóùú", replace_char: "*")
=> "à*à*èéì*ò*ù*"

GSMTexting.encode("àáàáèéìíòóùú", transliterate: true)
=> "àaàaèéìiòoùu"

GSMTexting.single_segment?("hi there")
=> true