Testing for invalid chars

[AP81]

Hi,

I have made a small utility for my work which tests hard drives (FAT32) for corruption.

Some of the corrupt hard drives contain filenames with invalid characters. I basically want to compare a string to a list of invalid characters to assess whether a file is invalid or not.

e.g.
Filename = '?#n120.mp3';
List of invalid characters = '/,\,:,#,?,",<,>,|';

if filename <> contain invalid character then passed := true
else passed = false.

This is the way I'm doing it (which seems pretty hack). Is there a better way?

  private
    { Private declarations }
    function isValidFile(name:string):boolean;  
...
var
invalid_chars : TStringList; //global

...

function TfrmCorruptionTest.isValidFile(name:string):boolean;
var
 i,j : integer;
 CharToCheck : ShortString;
begin
  i:=Length(name);
  for j := 0 to i do
    begin
      CharToCheck := Copy(name,j,1);
      if invalid_chars.IndexOf(CharToCheck) <> -1 then
        begin
          result := false;  //filename is invalid
          exit;
        end;
    end;
  result := true;           //filename is valid
end;

procedure TfrmCorruptionTest.Button1Click(Sender: TObject);
var
 FileNameToCheck : string;
begin
  FileNameToCheck := '?#n120.mp3';
  //FileNameToCheck := 'aaacccdd';
  if IsValidFile(FileNameToCheck) then showMessage('Valid')
  else ShowMessage('Invalid');
end;


procedure TfrmCorruptionTest.FormCreate(Sender: TObject);
begin
  //create list
  invalid_chars := TStringList.Create;
  //add invalid chars
  invalid_chars.Add('\');
  invalid_chars.Add('\');
  invalid_chars.Add('/');
  invalid_chars.Add(':');
  invalid_chars.Add('#');
  invalid_chars.Add('?');
  invalid_chars.Add('"');
  invalid_chars.Add('<');
  invalid_chars.Add('>');
  invalid_chars.Add('|');
end;

procedure TfrmCorruptionTest.FormDestroy(Sender: TObject);
begin
  invalid_Chars.Free;
end;

Any help or tips are appreciated.
Thanks.




------------------------------------
There's no place like 127.0.0.1
------------------------------------

 

[Glenn9999]

Actually the perfect tool for this would be to create a set for the task.

Then something like (if my memory serves me right):

var
invalid_char_list: set of char;

function valid_file(instr: string): boolean;
var
i: integer;
tag: boolean;
begin
tag := true;
for i := 1 to length(instr) do
if instr in invalid_char_list then
tag := false;
valid_file := tag;
end.