Long file names - short file names

Problem/Question/Abstract:

Long file names - short file names

Answer:

Here's a way to convert between short (8.3 DOS file names) and long file names:


{$APPTYPE console}

program LongShrt;

uses
  Windows, SysUtils;

function GetShortName(sLongName: string): string;
var
  sShortName: string;
  nShortNameLen: integer;
begin
  SetLength(sShortName, MAX_PATH);

  nShortNameLen := GetShortPathName(PChar(sLongName),
    PChar(sShortName), MAX_PATH - 1);

  if nShortNameLen = 0 then
  begin
    { handle errors... }
  end;

  SetLength(sShortName, nShortNameLen);

  Result := sShortName;
end;

function GetLongName(sShortName: string; var bError: boolean): string;
var
  bAddSlash: boolean;
  SearchRec: TSearchRec;
  nStrLen: integer;
begin
  bError := False;
  Result := sShortName;
  nStrLen := Length(sShortName);
  bAddSlash := False;

  if sShortName[nStrLen] = '\' then
  begin
    bAddSlash := True;
    SetLength(sShortName, nStrLen - 1);
    dec(nStrLen);
  end;

  if ((nStrLen - Length(ExtractFileDrive(sShortName))) > 0) then
  begin
    if FindFirst(sShortName, faAnyFile, SearchRec) = 0 then
    begin
      Result := ExtractFilePath(sShortName) + SearchRec.name;
      if bAddSlash then
      begin
        Result := Result + '\';
      end;
    end
    else
    begin
      // handle errors...       bError := True;
    end;
    FindClose(SearchRec);
  end;
end;

function GetLongName(sShortName: string): string;
var
  s: string;
  p: integer;
  bError: boolean;
begin
  Result := sShortName;

  s := '';
  p := Pos('\', sShortName);
  while (p > 0) do
  begin
    s := GetLongName(s + Copy(sShortName, 1, p), bError);
    Delete(sShortName, 1, p);
    p := Pos('\', sShortName);

    if (bError) then
      Exit;
  end;
  if sShortName <> '' then
  begin
    s := GetLongName(s + sShortName, bError);
    if bError then
      Exit;
  end;
  Result := s;
end;

const
  csTest = 'C:\program Files';

var
  sShort,
    sLong: string;

begin
  sShort := GetShortName(csTest);
  WriteLn('Short name for "' + csTest +
    '" is "' + sShort + '"');

  WriteLn;

  sLong := GetLongName(sShort);
  WriteLn('Long name for "' + sShort + '" is "' + sLong + '"');
end.