Mod user bad name or minimum and maximum username

[jotabonfim]

Hello boys, I would like to know if a module where I can control the amount of letters that the user types in time to make him the register on the site.
Example: the user would have to enter at least 5 letters to make the register and no more than 12 letters.

[V@no]

in register.php find
      $sql = "SELECT ".get_user_table_field("", "user_name")."
              FROM ".USERS_TABLE."
              WHERE ".get_user_table_field("", "user_name")." = '".strtolower($user_name)."'";


Insert below:
$lang['username_too_long'] = "Username is too long";
$lang['username_too_short'] = "Username is too short";
      if (strlen($user_name) > 12)
      {
        $msg .= (($msg != "") ? "<br />" : "").$lang['username_too_long'];
        $error = 1;
      }
      elseif (strlen($user_name) < 4)
      {
        $msg .= (($msg != "") ? "<br />" : "").$lang['username_too_short'];
        $error = 1;
      }
      else

[jotabonfim]

Hello Vano thanks for your help!
Tackling the mine site with your help.

In the same module is possible I use a function that validate the user's character?
Example 1: ok paulobrasil can record in the database
Example 2: paulo&brasil (& invalid characters) do not let record in the database

[V@no]

Lets assume you know REGEX a little

$lang['username_too_long'] = "Username is too long";
$lang['username_too_short'] = "Username is too short";
$lang['username_illegal_characters'] = "Username can only contein latin letters and numbers";
      if (preg_match("/[^a-zA-Z0-9]/", $user_name))
      {
        $msg .= (($msg != "") ? "<br />" : "").$lang['username_illegal_characters'];
        $error = 1;
      }
      if (strlen($user_name) > 12)
      {
        $msg .= (($msg != "") ? "<br />" : "").$lang['username_too_long'];
        $error = 1;
      }
      elseif (strlen($user_name) < 4)
      {
        $msg .= (($msg != "") ? "<br />" : "").$lang['username_too_short'];
        $error = 1;
      }

[jotabonfim]

Thank you for your Vano always help. 

It was great!!

[niad]

Hi V@no,
How about adding this mod for the guest names in comments?
Sometimes they put very long names and the structure of the comments area is getting very bad

[V@no]

insert that code in details.php above
    if ($user_name == "")  {