InetAddressValidator.pas

(*
   Copyright 2013 - Leonardo Herrera (leonardo.herrera@gmail.com)

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*)
unit InetAddressValidator;

interface

uses RegularExpressions;

const
  IPV4_REGEX = '^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$';

type

  TInetAddressValidator = class
  private
    ipv4Validator: TRegEx;
  public
    constructor Create; overload;
    function isValid(const inetAddress: String): Boolean;
    function isValidInet4Address(const inet4Address: String): Boolean;
  end;

implementation

uses SysUtils;

constructor TInetAddressValidator.Create;
begin
  inherited;
  ipv4Validator := TRegEx.Create(IPV4_REGEX);
end;

function TInetAddressValidator.isValid(const inetAddress: String): Boolean;
begin
  Result := isValidInet4Address(inetAddress);
end;

function TInetAddressValidator.isValidInet4Address(const inet4Address
  : String): Boolean;
var
  Match: TMatch;
  IpSegment: Integer;
  i: Integer;
begin
  Match := ipv4Validator.Match(inet4Address);

  if not Match.Success then
    Exit(false);

  IpSegment := 0;
  for i := 1 to Match.Groups.Count - 1 do
  begin
    try
      IpSegment := StrToInt(Match.Groups[i].Value);
    except
      Exit(false);
    end;

    if IpSegment > 255 then
      Exit(false);
  end;
  Result := true;
end;

end.