module SimpleCov::RawCoverage

def merge_file_coverage(file1, file2)
  return (file1 || file2).dup unless file1 && file2
  file1.map.with_index do |count1, index|
    count2 = file2[index]
    merge_line_coverage(count1, count2)
  end
end

def merge_line_coverage(count1, count2)
  sum = count1.to_i + count2.to_i
  if sum.zero? && (count1.nil? || count2.nil?)
    nil
  else
    sum
  end
end

def merge_results(*results)
  results.reduce({}) do |result, merged|
    merge_resultsets(result, merged)
  end
end

def merge_resultsets(result1, result2)
  (result1.keys | result2.keys).each_with_object({}) do |filename, merged|
    file1 = result1[filename]
    file2 = result2[filename]
    merged[filename] = merge_file_coverage(file1, file2)
  end
end