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Save early, delete when you need

There’s one interesting tidbit missing here, which is how deletion (SCI1 and later) is implemented. Namely by manipulating the .DIR file in the script, and not – as any sane person would do – with a kernel call.

So wrote Iskovlun in a comment some time back. Let’s see exactly how insane it really is.

; First we open up the directory file.
; Confusing, I know, to call it a directory file. Perhaps
; "catalog" would be better considering a directory is
; already something else. And in SCI32, they did!
((= fd (File new:))
  name: (DeviceInfo diMAKESAVEDIRNAME @str (gGame name?))
  open: fCREATE
)
 
; The format of a save game directory is pretty straight-
; forward -- a word for the index, then the name, terminated
; with an $0A, repeat until done, end with $FFFF.
 
; (File write:) requires a pointer to the data it is to write,
; so we need to put values into variables, rather than just
; passing them immediately. Well, unless you have SCI11+ with
; the extra file kernel calls I nabbed from SCI32 and a matching
; File class, in which case you could just do (File writeByte:
; $0A) if you were so inclined!
(= ret $0A0A)
 
; Now we write the number and name of each saved game, EXCEPT
; for the one that was selected for deletion.
(for ((= i 0)) (< i numGames) ((++ i))
  (if (!= i selected)
    (fd write: @[nums i] 2)
    (fd writeString: @[names (* i COMMENTBUFF)])
    (fd write: @ret 1)
  )
)
 
; Now we write the terminating $FFFF to finish the catalog
; I mean directory off.
(= ret -1)
(fd
  write: @ret 2
  close:
  dispose:
)
 
; Now that that's done, we can safely delete the actual
; save game file.
(DeviceInfo diMAKESAVEFILENAME (gGame name?) [nums selected])
(FileIO fiUNLINK @str)

I almost feel like doing the so-called sane thing and adding a DeleteGame kernel call to SCI11+.

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