strlen2.5

:strlen2.5  StrVar  [RtnVar]
:: http://ss64.org/viewtopic.php?id=424
  setlocal enableDelayedExpansion
  set "s=!%~1!"
  set len=0
  if defined s for /l %%N in (1,1,8192) do if "!s:~%%N,-%%N!" equ "" (
      set len=%%N
    goto :break
  )
  :break
  set /a len=2*!len!-1
  for %%E in (!len!) do (
    set s=!s:~%%E!
  )
  if "!s!" neq "" set /a len=!len!+1
  endlocal & if "%~2" neq "" (set %~2=%len%) else echo %len%
exit /b