Contents

require 'sms_tools/gsm_encoding'

module SmsTools
  class EncodingDetection
    MAX_LENGTH_FOR_ENCODING = {
      ascii: {
        normal:       160,
        concatenated: 153,
      },
      gsm: {
        normal:       160,
        concatenated: 153,
      },
      unicode: {
        normal:       70,
        concatenated: 67,
      },
    }.freeze

    attr :text

    def initialize(text)
      @text = text
    end

    def encoding
      @encoding ||=
        if text.ascii_only?
          :ascii
        elsif SmsTools.use_gsm_encoding? and GsmEncoding.valid?(text)
          :gsm
        else
          :unicode
        end
    end

    def ascii?
      encoding == :ascii
    end

    def gsm?
      encoding == :gsm
    end

    def unicode?
      encoding == :unicode
    end

    def concatenated?
      concatenated_parts > 1
    end

    def concatenated_parts
      if length <= MAX_LENGTH_FOR_ENCODING[encoding][:normal]
        1
      else
        (length.to_f / MAX_LENGTH_FOR_ENCODING[encoding][:concatenated]).ceil
      end
    end

    def maximum_length_for(concatenated_parts)
      message_type = concatenated_parts > 1 ? :concatenated : :normal

      concatenated_parts * MAX_LENGTH_FOR_ENCODING[encoding][message_type]
    end

    # Returns the number of symbols which the given text will eat up in an SMS
    # message, taking into account any double-space symbols in the GSM 03.38
    # encoding.
    def length
      length = text.length
      length += text.chars.count { |char| GsmEncoding.double_byte?(char) } if gsm?

      length
    end
  end
end

Version data entries

3 entries across 3 versions & 1 rubygems

Version	Path
smstools-0.2.0	lib/sms_tools/encoding_detection.rb
smstools-0.1.1	lib/sms_tools/encoding_detection.rb
smstools-0.1.0	lib/sms_tools/encoding_detection.rb