String length

:strlen [%1 -string, %2 variable to store result in]
setlocal
set string=%~1
rem if the string contains double quotes it will harm the IF checks
set string=%string:"=.%
set var=%~2
set /a counter=0
if "%string%" equ "" goto :return
:loop
    rem counter will hold the 1/2 of the string lenght
    set /a counter=%counter%+1
    set string=%string:~1,-1%
    if "%string%" equ "" (
        goto :endloop
    )

goto :loop
:endloop

set string=%~1
set string=%string:"=.%

set /a counter=2*%counter%-1
rem checking  if the string is with even or with uneven lenght
call set string=%%string:~%counter%%%
if "%string%" neq "" set /a counter=%counter%+1
echo %counter%
:return
endlocal & set %var%=%counter% >nul  2>&1