class SourceMap::Map

def self.decode_vlq_mappings(str, sources = [], names = [])
  mappings = []
  source_id       = 0
  original_line   = 1
  original_column = 0
  name_id         = 0
  VLQ.decode_mappings(str).each_with_index do |group, index|
    generated_column = 0
    generated_line   = index + 1
    group.each do |segment|
      generated_column += segment[0]
      generated = Offset.new(generated_line, generated_column)
      if segment.size >= 4
        source_id        += segment[1]
        original_line    += segment[2]
        original_column  += segment[3]
        source   = sources[source_id]
        original = Offset.new(original_line, original_column)
      else
        # TODO: Research this case
        next
      end
      if segment[4]
        name_id += segment[4]
        name     = names[name_id]
      end
      mappings << Mapping.new(source, generated, original, name)
    end
  end
  mappings
end