This is the second of a series of changes related to save/restore.
No EDITLEVEL bump has been included, because although the code
is changed extensively by this, the content of the savefiles have
not been changed.
Push the use of the structlevel bwrite() and mread() function use
out of the core and into sfstruct.c. This is groundwork for upcoming
changes.
In the core, replace the bwrite() and mread() calls with the
use of type-specific savefile output (Sfo) and savefile
input (Sfi) macros. The macros are defined in a new header file
savefile.h, which also contains the prototypes for the sfo_* and
sfi_* functions that the macros ultimately expand to. The functions
themselves are in src/sfbase.c.
On C99, each Sfo or Sfi macro expansion refers directly to the
corresponding type-specific sfo_* or sfi_* function.
If C23 or later is is use, the majority (all but 3 types) of the
macros refer to a single _Generic output routine sfo(nhfp, dt, tag),
and a single _Generic input routine sfi(nhfp, dt, tag), which handles
the dispatch of the type-specific underlying functions. This was
somewhat experimental, but turned out to be practical because the
compiler would gripe if the type for a variable was not included in
the _Generic when passed as an argument, so it could be fixed.
This alters the savefile verication process by having a common set
return values for the related functions such as uptodate(),
check_version(), etc. The new return values return more information
about savefile incompatibilities, beyond failure/sucess. The
additional information will be useful for an upcoming addition.
The expanded return values are:
SF_UPTODATE (0) everything matched and looks good
SF_OUTDATED (1) savefile is outdated
SF_CRITICAL_BYTE_COUNT_MISMATCH (2) critical size count mismatch
SF_DM_IL32LLP64_ON_ILP32LL64 (3) Windows x64 savefile on x86
SF_DM_I32LP64_ON_ILP32LL64 (4) Unix 64 savefile on x86
SF_DM_ILP32LL64_ON_I32LP64 (5) x86 savefile on Unix 64
SF_DM_ILP32LL64_ON_IL32LLP64 (6) x86 savefile on Windows x64
SF_DM_I32LP64_ON_IL32LLP64 (7) Unix 64 savefile on Windows x64
SF_DM_IL32LLP64_ON_I32LP64 (8) Windows x64 savefile on Unix 64
SF_DM_MISMATCH (9) some other mismatch
The callers in the core have been adjusted to deal with the expanded
return values.
Other miscellaneous inclusions:
- go.oracle_loc -> svo.oracle_loc.
- add a bit (1UL << 30) to called SFCTOOL_BIT as groundwork
for changes to follow.
Make some progress on a couple of next minor release checklist
items, hopefully without introducing too many new bugs. This
is just the initial commit, and work continues.
Checklist items:
Savefiles compatible between Windows versions, whether 64-bit
or 32-bit in little-endian field format.
Selection of file formats:
historical (structlevel saves),
lendian (little-endian, fieldlevel saves),
and just for proof-of-concept, ascii fieldlevel saves
(the ascii is huge! 10x bigger than little-endian).
For the fieldlevel save, all complex data structures recursively
get broken down until until it is one of the simple types that
can't be broken down any further, and that gets when it gets
written to the output file.
New files needed for this build:
hand-coded:
include/sfprocs.h
src/sfbase.c - really a dispatcher to one of the
output/input format routines.
src/sflendian.c - little-endian output writer/reader.
src/sfascii.c - ascii text output writer/reader.
auto-coded (generated):
include/sfproto.h
src/sfdata.c
This is just one approach. I'm sure there are countless others
and they have different pros and cons.
For producing the auto-coded files a utility called
universal-ctags, that is actively maintained and evolving,
was used to do all the heavy-lifting of parsing the
NetHack C sources to tabulate the data fields, and store
them in an intermediate file called util/nethack.tags
(not required for building NetHack if you already have a
generated include/sfproto.h and src/sfdata.c)
util/readtags (also not required for building NetHack
itself) will decipher the nethack.tags file and produce
the functions that can deal with the NetHack struct data
fields.
You can obtain the source for universal-ctags by cloning it
from here:
https://github.com/universal-ctags/ctags.git
The combination universal-ctags + util/readtags has been
tried and tested under both Windows and Linux, so it is
not tied to a particular platform.
Note: util/readtags will work only with universal-ctags
output, so other ctags are unlikely to work as-is.
Universal-ctags can be build from source very easily
under Linux, or under Windows using visual studio.
