/*
  Copyright Lutz Eymers <ixtab@polzin.com>, 1997
  Polzin GmbH, Duesseldorf
*/

function isDigit( ch )
{
 if ( (ch >= '0') && (ch <= '9') )
   return true;
 else
   return false;
}


function isAlpha( ch )
{
 if ( ((ch >= 'a') && (ch <= 'z')) || ((ch >= 'A') && (ch <= 'Z')) )
   return true;
 else
   return false;
}


function isAlnum( ch )
{
 if ( isAlpha( ch ) || isDigit( ch ) )
   return true;
 else
   return false;
}


function notIn( str1, str2 )
{
 var i = 0;
 var j = str2.length;
 for( ; i<j; i++ )
 {
   var str3 =  str2.charAt(i);
   if( str1.indexOf( str3 ) != -1 )
     return false;
 }
 return true;
}


function checkUsername( username, mustBeQuoted )
{
 var i = 0;
 var j = username.length;
 if ( username.charAt(0) != '"' )
 {
   if ( (username.charAt(0) <  ' ') || (username.charAt(0) >  '~')
         || !notIn( mustBeQuoted, username.charAt(0) ) )
     return false;
   for( i=1; i<j; i++ )
   {
     if ( ( (username.charAt(i) < ' ') || (username.charAt(i) >  '~')
           || !notIn ( mustBeQuoted, username.charAt(i) ) )
          && ( username.charAt(i-1) != '\\' ) )
       return false;
   }
 }
 else
 {
   if ( username.charAt( j-1 ) != '"' )
     return false;
   for( i=1; i<j-1; i++ )
   {
     if ( ( (username.charAt(i) == '\n') || (username.charAt(i) == '\r')
           || (username.charAt(i) == '\"') )
         && (username.charAt(i-1) != '\\') )
       return false;
   }

 }
 return true;
}


function checkNr ( nr )
{
 var i=0;
 var j=nr.length;

 if( j < 1 )
   return false;

 for( ; i<j; i++ )
   if( ( nr.charAt(i) < '0' ) || ( nr.charAt(i) > '9' ) )
     return false;

 return true;
}


function checkIpnr( ipnr )
{
 var iL=0;
 var iC=0;
 var i=0;
 var sNr = "";

 for( ; i< ipnr.length; i++ )
 {
   if ( ipnr.charAt(i) == '.' )
   {
     if ( !iL || (iL> 3) || parseInt( sNr,10 ) > 255 )
       return false;
     iC++;
     iL = 0;
     sNr = "";
     continue;
   }
   if ( isDigit ( ipnr.charAt(i) ) )
   {
     iL++;
     sNr = sNr + ipnr.charAt(i);
     continue;
   }
   return false;
 }

 if ( parseInt( sNr,10 ) > 255 )
   return false;
 if ( ( (iC==3) && (iL>=1) && (iL<=3) ) || ( (iC==4) && (!iL) )  )
   return true;
 else
   return false;
}


function checkFqdn( fqdn )
{
 var iL=0;
 var iC=0;
 var i=fqdn.length-1;

 if ( (fqdn.charAt(0) == '.') || (fqdn.charAt(0) == '-') )
   return false;
 if ( fqdn.charAt(i) == '.' )
   i=i-1;

 for( ; i>=0; i-- )
 {
   if ( fqdn.charAt(i) == '.' )
   {
     if ( iL < 2 && iC < 2 )
       return false;
     if ( fqdn.charAt(i-1) == '-' )
       return false;
     iC++;
     iL = 0;
     continue;
   }
   if ( isAlnum ( fqdn.charAt(i) ) )
   {
     iL++;
     continue;
   }
   if ( fqdn.charAt(i) == '-' )
   {
     if ( !iL )
       return false;
     iL++;
     continue;
   }
   return false;
 }

 if ( !iC || ( iL == 1 && iC < 2 ) || ( !iL && iC==1 ) ) {
   return false;
 }

 return true;

}


function checkHostname( hostname )
{
 if ( hostname.charAt(0) == '[' )
 {
   if ( hostname.charAt(hostname.length-1) != ']' )
     return false;
   var ipnr = hostname.substring( 1, hostname.length -1 );
     return checkIpnr( ipnr );
 }

 if ( hostname.charAt(0) == '#' )
 {
   var nr = hostname.substring( 1, hostname.length );
     return checkNr( nr );
 }

 return checkFqdn( hostname );
}


function checkEmailAdr( address )
{
 var status = true;
 var username = "";
 var hostname = "";

 if ( address.length < 8 )
   return false;

 var seperate = address.lastIndexOf("@");
 if ( seperate == -1 )
   return false;

 username = address.substring(0, seperate );
 if ( ! checkUsername( username, "<>()[],;:@\" " ) )
   return false;

 hostname = address.substring(seperate+1, address.length );
 if ( ! checkHostname( hostname ) )
   return false;

 return true;
}


function checkEmail( email, allowFullname )
{
 var existFullname = false;
 var status = true;
 var fullname = "";
 var adress = "";
 if ( email.length < 8 )
   return false;
 var emailBegin = email.indexOf("<");
 var emailEnd = email.lastIndexOf(">");

 if ( (emailBegin == -1) && (emailEnd == -1) )
   return checkEmailAdr( email );

 if ( ( (emailBegin == -1) && (emailEnd != -1) )
     || ( (emailBegin != -1) && (emailEnd == -1) ) )
   return false;

 adress = email.substring( emailBegin+1, emailEnd );

 if ( ! checkEmailAdr( adress ) )
   return false;

 if ( email.length == adress.length + 2 )
   return true;
 else
   if ( ! allowFullname )
     return false;

 if ( emailEnd == email.length - 1 )
 {
   if ( emailBegin == 0 )
     return true;
   if ( email.charAt( emailBegin -1 ) != ' ' )
     return false;
   fullname = email.substring( 0, emailBegin-1 );
   return checkUsername ( fullname, "<>()[],;:@\"" );
 }

 return false ;

}