Validar email (funcion en PAS)

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Código Delphi [-]
Unit validate_email;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

implementation

Function ValidEmail(email: String): Boolean;
  // Returns True if the email address is valid
  // Author: Ernesto D'Spirito
Const
  // Valid characters in an "atom"
  atom_chars = [#33..#255] - ['(', ')', '<', '>', '@', ',', ';', ':',
    '\', '/', '"', '.', '[', ']', #127];
  // Valid characters in a "quoted-string"
  quoted_string_chars = [#0..#255] - ['"', #13, '\'];
  // Valid characters in a subdomain
  letters = ['A'..'Z', 'a'..'z'];
  letters_digits = ['0'..'9', 'A'..'Z', 'a'..'z'];
  subdomain_chars = ['-', '0'..'9', 'A'..'Z', 'a'..'z'];
Type
  States = (STATE_BEGIN, STATE_ATOM, STATE_QTEXT, STATE_QCHAR,
    STATE_QUOTE, STATE_LOCAL_PERIOD, STATE_EXPECTING_SUBDOMAIN,
    STATE_SUBDOMAIN, STATE_HYPHEN);
Var
  State: States;
  i, n, subdomains: Integer;
  c: Char;
Begin
  State := STATE_BEGIN;
  n := Length(email);
  i := 1;
  subdomains := 1;
  While (i <= n) Do
  Begin
    c := email[i];
    Case State Of
      STATE_BEGIN:
        If c In atom_chars Then
          State := STATE_ATOM
        Else If c = '"' Then
          State := STATE_QTEXT
        Else
          break;
      STATE_ATOM:
        If c = '@' Then
          State := STATE_EXPECTING_SUBDOMAIN
        Else If c = '.' Then
          State := STATE_LOCAL_PERIOD
        Else If Not (c In atom_chars) Then
          break;
      STATE_QTEXT:
        If c = '\' Then
          State := STATE_QCHAR
        Else If c = '"' Then
          State := STATE_QUOTE
        Else If Not (c In quoted_string_chars) Then
          break;
      STATE_QCHAR:
        State := STATE_QTEXT;
      STATE_QUOTE:
        If c = '@' Then
          State := STATE_EXPECTING_SUBDOMAIN
        Else If c = '.' Then
          State := STATE_LOCAL_PERIOD
        Else
          break;
      STATE_LOCAL_PERIOD:
        If c In atom_chars Then
          State := STATE_ATOM
        Else If c = '"' Then
          State := STATE_QTEXT
        Else
          break;
      STATE_EXPECTING_SUBDOMAIN:
        If c In letters Then
          State := STATE_SUBDOMAIN
        Else
          break;
      STATE_SUBDOMAIN:
        If c = '.' Then
        Begin
          Inc(subdomains);
          State := STATE_EXPECTING_SUBDOMAIN;
        End
        Else If c = '-' Then
          State := STATE_HYPHEN
        Else If Not (c In letters_digits) Then
          break;
      STATE_HYPHEN:
        If c In letters_digits Then
          State := STATE_SUBDOMAIN
        Else If c <> '-' Then
          break;
    End;
    Inc(i);
  End;
  If i <= n Then
    Result := False
  Else
    Result := (State = STATE_SUBDOMAIN) And (subdomains >= 2);
End;
End.

hola....estoy intentando utilizar este archivo PAS en un proyecto C++ builder ya que la funcion esta en pascal (para validar email)


pero creo que me falta declarar la funcion en algun sitio porque me dice UNRESSOLVED EXTERNAL ValidEmail(System::UnicodeString)


alguien que pueda analizarlo??? compilar compila bien sin errores