I am working at the moment making masks v3 + 3 ways compression with Inno support.
Method 1
With that said, Inno setup has isdone.dll which has these parameters,
""
if not ISArcExtract ( 0, 0, ExpandConstant('{src}\Setup-1.arc'), ExpandConstant('{app}'), '', false, '', ExpandConstant('{tmp}\arc.ini'), ExpandConstant('{app}'), False) then break; ""
the second 0 is the progress bar, if you leave it to 0 the setup will create a records.inf which you can then use to smoothen out your progress bar.
Method 2
if you have 3 Freearc files however and you want to manually put a progress bar here is how
if not ISArcExtract ( 0, 30, ExpandConstant('{src}\data1.bin'), ExpandConstant('{app}'), '', false, 'yourpassword', ExpandConstant('{tmp}\arc.ini'), ExpandConstant('{app}'), False) then break;
if not ISArcExtract ( 0, 30, ExpandConstant('{src}\data2.bin'), ExpandConstant('{app}'), '', false, 'yourpassword', ExpandConstant('{tmp}\arc.ini'), ExpandConstant('{app}'), False) then break;
if not ISArcExtract ( 0, 40, ExpandConstant('{src}\data3.bin'), ExpandConstant('{app}'), '', false, 'yourpassword', ExpandConstant('{tmp}\arc.ini'), ExpandConstant('{app}'), False) then break;
the sum of all second column must be 100!!!!
I officially MOVE here:
https://fileforums.com/showthread.php?t=102689
This is no longer a valid space to talk about Masks
enjoy v3 and hope you suggest more to go