[Scummvm-tracker] [ScummVM] #10758: QFG4: Autosave SCI Script Deletes Manual Savegames...

[Vhati]

#10758: QFG4: Autosave SCI Script Deletes Manual Savegames...
--------------------------------+-------------------------
  Reporter:  Vhati              |      Owner:  (none)
      Type:  defect             |     Status:  new
  Priority:  high               |  Component:  Engine: SCI
Resolution:                     |   Keywords:  SCI32
      Game:  Quest for Glory 4  |
--------------------------------+-------------------------

Comment (by Vhati):

 @digitall:
 > I wonder if the original forced you to have only 10 savegames

 I think you are correct.

 https://github.com/scummvm/scummvm/blob/master/engines/sci/engine/kfile.cpp
 bp_kernel GetSaveFiles break
 bp_kernel FileIOOpen break
 bp_kernel FileIOClose break
 bp_kernel FileIOUnlink break
 bp_kernel MakeSaveFileName break
 \\
 \\
 Script 0, Glory::save() calls kGetSaveFiles() and localproc_21c5()
 procedure in a loop. The procedure is responsible for deleting everything.
 Looks like kCheckFreeSpace() is the loop's condition?

 {{{
 (procedure (localproc_21c5 param1 param2 param3 param4 &tmp temp0 temp1
 newFile temp3 newStr)
         (= newStr (Str new:))
         (MakeSaveCatName (newStr data?) (global1 name?))
         # kFileIO(Open): 000f:08b8 ('fake.cat'), 2 = 32100
         ((= newFile (File new:)) name: (newStr data?) open: 2)
         (= temp1 0)
         # Loop calls kFileIO(WriteRaw) to write every slot's title to the
 catalog.
         (while (< temp1 param3)
                 (if (!= temp1 param1)
                         (= temp3 (param4 at: temp1))
                         (newStr
                                 at: 0 (& temp3 $00ff)
                                 at: 1 (& (>> temp3 $0008) $00ff)
                                 at: 2 0
                         )
                         (newFile write: (newStr data?) 2)
                         (= temp0 (Str new: 36))
                         (temp0 copyToFrom: 0 param2 (* temp1 36) 36)
                         (newFile write: (temp0 data?) 36)
                         (temp0 dispose:)
                         (= temp0 0)
                 )
                 (++ temp1)
         )
         (newStr at: 0 255 at: 1 255)
         # kFileIO(Close): 32100 = 1
         (newFile write: (newStr data?) 2 close: dispose:)
         # kMakeSaveFileName: 000f:08b8 ('sci.033'), 0001:4c0d ('Glory'),
 32 = 000f:08b8
         (MakeSaveFileName
                 (newStr data?)
                 (global1 name?)
                 (param4 at: param1)
         )
         # kFileIO(Unlink): 000f:08b8 ('sci.033') = 1
         (FileIO fiUNLINK (newStr data?))
         (newStr dispose:)
 )
 }}}

 Throughout the loop, my breakpoint reports "kCheckFreeSpace: 000f:0000
 ('') = 1"

 Save has a couple of loops. This might be it?
 {{{
                                         (while
                                                 (and
                                                         (> temp9 0)
                                                         (or
                                                                 (not
 (CheckFreeSpace (global29 data?)))
                                                                 (>= temp9
 20)
                                                         )
                                                 )
                                                 (localproc_21c5 (- temp9
 1) newStr temp9 temp1)
                                                 (= temp9
                                                         (GetSaveFiles
                                                                 (global1
 name?)
                                                                 (newStr
 data?)
                                                                 (temp1
 data?)
                                                         )
                                                 )
                                         )
 }}}

 The loop has another condition "(>= temp9 20)". That looks suspicious.
 After all the deletions, I'm left with 20 files.
 \\
 \\
 A 20 slot cap has been patched away in two other places.

 https://github.com/scummvm/scummvm/blob/b749116cbe1f710caa6fa225eef49af33e769e79/engines/sci/engine/script_patches.cpp#L254

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Ticket URL: <https://bugs.scummvm.org/ticket/10758#comment:14>
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