Even though strcpy in SegManager isn't a problem, our forbidden symbols
list being defined at preprocessor level, we won't be able to use this
name anymore.
Passing overlapping buffers to C standard library memcpy, strcpy,
and strncpy is undefined behavior. In SSCI these operations would
perform a forward copy, and most stdlib implementations do the
same, but at least newer Linux glibc on x86 copies bytes in
reverse, so just using the standard library on this platform
results in broken output.
Because SSCI used a blind forward copy instead of memmove for
overlapping copy operations, this patch implements an explicit
forward copy to ensure that overlapping copies continue to operate
the same as in SSCI.
This fixes the Island of Dr. Brain v1.1 flamingo puzzle
(script 185, flamingos::init, localCall 4c3) on platforms that do
not perform forward copy in memcpy/strcpy/strncpy.
Thanks to @moralrecordings for research on this bug and an initial
patch using memmove.
Closes gh-1034.
When a game deletes a script and then loads the same script again
before it has been fully deallocated,
SegManager::instantiateScript tries to reuse the same script
& locals segments, but it was failing to reuse the old locals
segment because Script::freeScript would unconditionally clear
the old locals SegmentId, which meant the old locals segment would
just leak.
This patch does not fix old save games which may contain orphaned
locals segments, but should prevent the problem from occurring
going forward. (It is possible to clean up these old save games,
but this is not a big leak so it doesn't seem worth the extra
effort to do so.)
This change invalidates earlier SCI32 save games, which separated
arrays and strings in an incompatible manner. Old save games
contain invalid references to a string segment which no longer
exists, and contain incompatible array structures that lack
critical type information.
When objects are added to a SegmentObjTable, it may cause the
internal storage for the table to expand and move to a new
region of memory. When this happens, all pointers to objects held
by a SegmentObjTable of the same type would be invalidated, due
to an implementation detail that should not be exposed. To prevent
this, objects are now allocated separately on the heap, so even if
the table's storage moves due to insertions, the objects owned by
the table will not, so references remain valid for the lifetime of
the object.
When new bitmaps are added and the underlying Common::Array needs
to move to expand, this invalidates all pointers to bitmaps, which
makes it basically impossible to use the bitmap segment since you
never know if a reference is going to be invalidated due to an
array move.
To solve this, BitmapTable is changed to hold pointers to
SciBitmaps that are allocated separately on the heap instead, so
when those bitmaps are looked up, the resulting pointers are valid
for the lifetime of the bitmap, instead of the lifetime of the
Common::Array used internally by BitmapTable.
Bitmaps in ScrollWindow and Robot code are managed by the kernel
and not by game scripts, although they must be able to be
referenced through a reg_t. To prevent incorrect GC of bitmaps
that are in use but not referenced by any game script, explicit
memory management of hunk entries can be enabled.
It's perfectly normal behavior to have locals with a smaller segment ID
than the ID of their respective script, e.g. when scripts are
uninstantiated and then instantiated again
When resetting the segment manager, sometimes the locals block for a
script is placed in a segment smaller than the script itself. This
shouldn't be happening, but it isn't fatal, however it should be resolved
in a proper manner
No functionality change has been made with this commit. This avoids
setting and getting the reg_t members directly, and is the basis of any
future work on large SCI3 scripts (larger than 64KB)
find -name '*.h' -or -name '*.cpp' | xargs sed -r -i 's@\(([A-Za-z0-9]+)\*\)@(\1 *)@g'
This seems to have caught some params as well which is not undesirable IMO.
It also caught some strings containing this which is undesirable so I
excluded them manually. (engines/sci/engine/kernel_tables.h)
Le Philousophe
Eugene Sandulenko
Orgad Shaneh
sluicebox
Henrik "Henke37" Andersson
Filippos Karapetis
Colin Snover
Willem Jan Palenstijn
Johannes Schickel
Martin Kiewitz
Filippos Karapetis
Tarek Soliman
Max Horn
Matthew Hoops