This bug existed in SSCI and was pulled in carelessly during
initial implementation of SciArray. Closer examination of SCI3
reveals that this only happened to work in SSCI because it would
always allocate on the first resize, and would always allocate 25
extra elements per allocation.
In GK2, restoring a save game causes the segment manager to reset
in the middle of a kListFirstTrue call, which invalidates all
pointers and reg_ts to stored data. This means that when
kListFirstTrue tries to decrement the list recursion counter at
the end of iteration, it is writing to freed memory, potentially
resulting in heap corruption.
SCI3 added checks to prevent this from happening, but these checks
seem like they should have also been applied to some SCI2.1 games
as well (like GK2).
Since there should be no negative side-effect to this check, it
is applied universally to all SCI32 games.
This fixes the crash in PQ2 1.002.011. There is another workaround
for the same problem from ticket Trac#5223, but it uses a different
method name that does not match in this version of PQ2.
Fixes Trac#9670.
In SSCI, all files opened through kFileIO are writable. Most of
the time this does not matter and the engine can get away with
using read-only streams, but when chase.dat is opened by Phant1
from the retry dialogue during the chase, it needs to be writable
because game code puts a '98' marker in the chase data. If this
write does not occur, the game gets stuck in a loop looking for
the marker.
Transition timings were originally chosen largely by feel in SQ6,
as there was little other evidence to determine the correct speed.
As additional games started being playable in ScummVM, it became
apparent that these speeds were not quite right.
Additional adjustments may be needed in the future, but these new
timings seem to be somewhat closer to expectations than before.
Learning the bytecode for file op is necessary when creating
workaround signatures, as the signature-finding mechanism does not
currently ignore line/file instructions.
1. pushi opcode now displays decimal value and selector value (if
one exists) in-line
2. lofsa, lofss, and super opcodes now display resolved
object/class names
3. Opcode arguments are visually aligned
Silently returning zero values can cause games to break. e.g.
Shivers 1 room 35170 has a script bug where vJoystick::handleEvent
makes a super call which causes doVerb to be called a second time
with no arguments. In the original game this happened to work
because the value already on the stack happened to be 1. In ScummVM
this silently (unless VM debug messages were enabled) failed
because the uninitialised read value was forced to 0.
KQ7 1.51 writes int16s from the save game catalogue into a Str
object, then retrieves byte 0 from the string and compares it to
-1. This happens to work out because (1) characters were treated
as signed in SCI2.1early and earlier, and (2) int16s in the save
game catalogue were little-endian.
In SCI2.1mid and later, this trick no longer works because
characters are treated as unsigned and get zero-extended instead.
Fixes Trac#9632.
In SSCI, strchr is called against a hex string with a duplicate 0
("01234567890abcdef") to determine the decimal value of hex digits,
which means the values A-F are incorrectly interpreted as 11-16
instead of 10-15.
All versions of SSCI with support for hexadecimal escape sequences
in messages (starting somewhere around Feb 1993) are buggy.
The native save/load dialog of SCI32 relies on this defect to
render the up and down arrows of the game selector.
Fixes Trac#9582.
Willem Jan Palenstijn
Colin Snover
Martin Kiewitz
Omer Mor