Module: PDUTools::Helpers

Included in:
Decoder, Encoder
Defined in:
lib/pdu_tools/helpers.rb

Constant Summary collapse

GSM_03_38_ESCAPES = 
{
    "@" => "\x00",
    "$" => "\x02",
    "_" => "\x11",
    "^" => "\x1B\x14",
    "{" => "\x1B\x28",
    "}" => "\x1B\x29",
    "\\" => "\x1B\x2F",
    "[" => "\x1B\x3C",
    "~" => "\x1B\x3D",
    "]" => "\x1B\x3E",
    "|" => "\x1B\x40"
    # "\x80" => "\x1B\x65"
}

Instance Method Summary collapse

Instance Method Details

#dec2hexbyte(dec) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 33

def dec2hexbyte dec
  "%02X" % dec
end

#decode16bit(data, length) ⇒ Object

Decodes 16bit UTF-16 string into UTF-8 string



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# File 'lib/pdu_tools/helpers.rb', line 118

def decode16bit data, length
  data.split('').in_groups_of(4).collect()
  double_octets = data.split('').in_groups_of(4).map(&:join).map{|x| x.to_i(16) }[0, length / 2] # integer values
  double_octets.collect do |o|
    [o].pack('S')
  end.join.force_encoding('utf-16le').encode('utf-8')
end

#decode7bit(textdata, length = nil, offset = 1) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 76

def decode7bit textdata, length = nil, offset = 1
  ret = ""
  bytes = []
  textdata.split('').each_slice(2) do |s|
    bytes << "%08b" % s.join.to_i(16)
  end

  cur_septet = ""
  next_septet = ""
  last_char = ""

  bytes.each_with_index do |byte, index|
    to_take = ([0,1].include? offset) ? 7 : 8-offset
    cur_septet.prepend byte[offset, to_take]
    next_septet = byte[0,offset] if offset > 0
    ret << cur_septet.to_i(2).chr

    if offset == 7
      offset = 1
      ret << next_septet.to_i(2).chr
      cur_septet = ""
    else
      offset += 1
      cur_septet = next_septet
    end
    next_septet = nil
  end
  if length
    ret[0..length - 1]
  else
    ret
  end
end

#decode8bit(data, length) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 110

def decode8bit data, length
  octets = data.split('').in_groups_of(2).collect(&:join)[0, length]
  octets.collect do |o|
    o.to_i(16).chr
  end.join
end

#encode7bit(string, padding = 0) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 37

def encode7bit string, padding=0
  current_byte = 0
  offset = padding
  packed = []
  string.chars.to_a.each_with_index do |char, i|
    # cap off any excess bytes
    septet = char.ord & 0x7F
    # append the septet and then cap off excess bytes
    current_byte |= (septet << offset) & 0xFF
    offset += 7
    if offset > 7
      # the current byte is full, add it to the encoded data.
      packed << current_byte
      # shift left and append the left shifted septet to the current byte
      septet = septet >> (7 - (offset - 8 ))
      current_byte = septet
      # update offset
      offset -= 8
    end
  end
  packed << current_byte if offset > 0 # append the last byte
  packed.collect{|c| "%02X" % c }.join
end

#encode8bit(string) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 61

def encode8bit string
  string.chars.to_a.collect do |char|
    "%04X" % char.ord
  end.join
end

#gsm0338_to_utf8(string) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 25

def gsm0338_to_utf8 string
  GSM_03_38_ESCAPES.each do |replace, find|
    string.gsub! find, replace
  end
  string
end

#normal2swapped(string) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 67

def normal2swapped string
  string << "F" if string.length.odd?
  string.scan(/../).collect(&:reverse).join
end

#swapped2normal(string) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 72

def swapped2normal string
  string.scan(/../).collect(&:reverse).join.gsub(/F$/,'')
end

#utf8_to_gsm0338(string) ⇒ Object 



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# File 'lib/pdu_tools/helpers.rb', line 18

def utf8_to_gsm0338 string
  GSM_03_38_ESCAPES.each do |find, replace|
    string.gsub! find, replace
  end
  string
end