module Zip5

# File lib/zip5.rb, line 30
def Zip5.zip4(input)
  input = input.to_s.gsub(/\.\d*\z/, '')
  memo = nil
  if input =~ /\A\d+\-(\d+)\z/
    memo = $1.to_i
  elsif zip5 = zip5(input)
    hunk = zip5.gsub /\A0*/, ''
    pat = /\A0*#{hunk}/
    memo = input.gsub(pat, '').to_i
  end
  if memo and memo > 0
    '%04d' % memo.to_i
  end
end

# File lib/zip5.rb, line 6
def Zip5.zip5(input)
  input = input.to_i.to_s.gsub('-', '')
  memo = case input.length
  when 9
    input[0,5]
  when 8
    '0' + input[0,4]
  when 7
    '00' + input[0,3]
  when 5
    input
  when 4
    '0' + input
  when 3
    '00' + input
  else
    nil
  end
  if ENV['VERBOSE'] == 'true' and not VALID.include?(memo.to_i)
    $stderr.puts "warning: looks like a bad zip5 (expected 00500..99950): #{memo}"
  end
  memo
end