class GeoIP

# File lib/geoip.rb, line 176
def initialize(filename, options = {})
  if options[:preload] || !IO.respond_to?(:pread)
    @mutex = Mutex.new
  end

  @use_pread = IO.respond_to?(:pread) && !options[:preload]

  @options = options
  @database_type = GEOIP_COUNTRY_EDITION
  @record_length = STANDARD_RECORD_LENGTH
  @file = File.open(filename, 'rb')

  detect_database_type!

  preload_data if options[:preload]
end

# File lib/geoip.rb, line 374
def asn(hostname)
  ip = lookup_ip(hostname)

  # Convert numeric IP address to an integer
  ipnum = iptonum(ip)

  if (@database_type != GEOIP_ASNUM_EDITION)
    throw "Invalid GeoIP database type, can't look up ASN by IP"
  end

  pos = seek_record(ipnum)
  off = pos + (2*@record_length - 1) * @database_segments[0]

  record = atomic_read(MAX_ASN_RECORD_LENGTH, off)
  record = record.sub(/\000.*/n, '')

  # AS####, Description
  ASN.new($1, $2) if record =~ /^(AS\d+)\s(.*)$/
end

# File lib/geoip.rb, line 306
def city(hostname)
  ip = lookup_ip(hostname)

  if (@database_type == GEOIP_CITY_EDITION_REV0 ||
      @database_type == GEOIP_CITY_EDITION_REV1)
    # Convert numeric IP address to an integer
    ipnum = iptonum(ip)
    pos = seek_record(ipnum)
  elsif (@database_type == GEOIP_CITY_EDITION_REV1_V6)
    ipaddr = IPAddr.new ip
    pos = seek_record_v6(ipaddr.to_i)
  else
    throw "Invalid GeoIP database type, can't look up City by IP"
  end

  # This next statement was added to MaxMind's C version after it was
  # rewritten in Ruby. It prevents unassigned IP addresses from returning
  # bogus data.  There was concern over whether the changes to an
  # application's behaviour were always correct, but this has been tested
  # using an exhaustive search of the top 16 bits of the IP address space.
  # The records where the change takes effect contained *no* valid data. 
  # If you're concerned, email me, and I'll send you the test program so
  # you can test whatever IP range you think is causing problems,
  # as I don't care to undertake an exhaustive search of the 32-bit space.
  unless pos == @database_segments[0]
    read_city(pos, hostname, ip)
  end
end

# File lib/geoip.rb, line 212
def country(hostname)
  if (@database_type == GEOIP_CITY_EDITION_REV0 ||
      @database_type == GEOIP_CITY_EDITION_REV1 ||
      @database_type == GEOIP_CITY_EDITION_REV1_V6)
    return city(hostname)
  end

  if (@database_type == GEOIP_REGION_EDITION_REV0 ||
      @database_type == GEOIP_REGION_EDITION_REV1)
    return region(hostname)
  end

  ip = lookup_ip(hostname)
  if (@database_type == GEOIP_COUNTRY_EDITION ||
      @database_type == GEOIP_PROXY_EDITION ||
      @database_type == GEOIP_NETSPEED_EDITION)
      # Convert numeric IP address to an integer
      ipnum = iptonum(ip)
      code = (seek_record(ipnum) - COUNTRY_BEGIN)
  elsif @database_type == GEOIP_COUNTRY_EDITION_V6
    ipaddr = IPAddr.new ip
    code = (seek_record_v6(ipaddr.to_i) - COUNTRY_BEGIN)
  else
    throw "Invalid GeoIP database type, can't look up Country by IP"
  end

  Country.new(
    hostname,                   # Requested hostname
    ip,                         # Ip address as dotted quad
    code,                       # GeoIP's country code
    CountryCode[code],          # ISO3166-1 alpha-2 code
    CountryCode3[code],         # ISO3166-2 alpha-3 code
    CountryName[code],          # Country name, per ISO 3166
    CountryContinent[code]      # Continent code.
  )
end

# File lib/geoip.rb, line 405
def each
  return enum_for unless block_given?

  if (@database_type != GEOIP_CITY_EDITION_REV0 &&
      @database_type != GEOIP_CITY_EDITION_REV1)
    throw "Invalid GeoIP database type, can't iterate thru non-City database"
  end

  @iter_pos = @database_segments[0] + 1
  num = 0

  until ((rec = read_city(@iter_pos)).nil?)
    yield rec
    print "#{num}: #{@iter_pos}\n" if((num += 1) % 1000 == 0)
  end

  @iter_pos = nil
  return self
end

# File lib/geoip.rb, line 344
def isp(hostname)
  ip = lookup_ip(hostname)

  # Convert numeric IP address to an integer
  ipnum = iptonum(ip)

  if (@database_type != GEOIP_ISP_EDITION &&
      @database_type != GEOIP_ORG_EDITION)
    throw "Invalid GeoIP database type, can't look up Organization/ISP by IP"
  end

  pos = seek_record(ipnum)
  off = pos + (2*@record_length - 1) * @database_segments[0]

  record = atomic_read(MAX_ORG_RECORD_LENGTH, off)
  record = record.sub(/\000.*/n, '')
  record.start_with?('*') ? nil : ISP.new(record)
end

# File lib/geoip.rb, line 264
def region(hostname)
  if (@database_type == GEOIP_CITY_EDITION_REV0 ||
      @database_type == GEOIP_CITY_EDITION_REV1 ||
      @database_type == GEOIP_CITY_EDITION_REV1_V6)
    return city(hostname)
  end

  if (@database_type == GEOIP_REGION_EDITION_REV0 ||
      @database_type == GEOIP_REGION_EDITION_REV1)
    ip = lookup_ip(hostname)
    ipnum = iptonum(ip)
    pos = seek_record(ipnum)
  else
    throw "Invalid GeoIP database type, can't look up Region by IP"
  end

  unless pos == @database_segments[0]
    read_region(pos, hostname, ip)
  end
end

# File lib/geoip.rb, line 735
def atomic_read_unguarded(length, offset)
  if @use_pread
    IO.pread(@file.fileno, length, offset)
  else
    io = @contents || @file
    io.seek(offset)
    io.read(length)
  end
end

# File lib/geoip.rb, line 526
def lookup_region_name(country_iso2, region_code)
  country_regions = RegionName[country_iso2]
  country_regions && country_regions[region_code]
end

# File lib/geoip.rb, line 428
def preload_data
  @file.seek(0)
  @contents = StringIO.new(@file.read)
  @file.close
end

# File lib/geoip.rb, line 681
def seek_record_v6(ipnum)

  # Binary search in the file.
  # Records are pairs of little-endian integers, each of @record_length.
  offset = 0
  mask = 1 << 127

  127.downto(0) do |depth|
    off = (@record_length * 2 * offset)
    buf = atomic_read(@record_length * 2, off)

    buf.slice!(0...@record_length) if ((ipnum & mask) != 0)
    offset = le_to_ui(buf[0...@record_length].unpack("C*"))

    if (offset >= @database_segments[0])
      return offset
    end

    mask >>= 1
  end

end