104 Commits

Author SHA1 Message Date
87e98e6715 Distinguish MOVE_UNUSED from MOVE_NO_EFFECT in Mines 2023-06-11 00:33:27 +01:00
a9af3fda1d Rename UI_UPDATE as MOVE_UI_UPDATE
All the other constants named UI_* are special key names that can be
passed to midend_process_key(), but UI_UPDATE is a special return value
from the back-end interpret_move() function instead.  This renaming
makes the distinction clear and provides a naming convention for future
special return values from interpret_move().
2023-06-11 00:33:27 +01:00
b08c13f5f4 Update a comment in Mines to reflect that we have user prefs now 2023-06-11 00:32:40 +01:00
0058331aeb New backend functions: get_prefs and set_prefs.
These are similar to the existing pair configure() and custom_params()
in that get_prefs() returns an array of config_item describing a set
of dialog-box controls to present to the user, and set_prefs()
receives the same array with answers filled in and implements the
answers. But where configure() and custom_params() operate on a
game_params structure, the new pair operate on a game_ui, and are
intended to permit GUI configuration of all the settings I just moved
into that structure.

However, nothing actually _calls_ these routines yet. All I've done in
this commit is to add them to 'struct game' and implement them for the
functions that need them.

Also, config_item has new fields, permitting each config option to
define a machine-readable identifying keyword as well as the
user-facing description. For options of type C_CHOICES, each choice
also has a keyword. These keyword fields are only defined at all by
the new get_prefs() function - they're left uninitialised in existing
uses of the dialog system. The idea is to use them when writing out
the user's preferences into a configuration file on disk, although I
haven't actually done any of that work in this commit.
2023-04-23 13:25:06 +01:00
a4fca3286f Pass a game_ui to compute_size, print_size and print.
I'm about to move some of the bodgy getenv-based options so that they
become fields in game_ui. So these functions, which could previously
access those options directly via getenv, will now need to be given a
game_ui where they can look them up.
2023-04-21 16:18:04 +01:00
0d86fe4b74 Move obfuscator tests into obfusc.c.
I just found these self-tests lying around in mines.c under an #ifdef
that nobody ever enables. Let's put them somewhere more sensible! We
already have a separate tool for working with the obfuscation system
in a puzzle-independent way, and it seems reasonable to put them in
there.
2023-04-16 08:44:33 +01:00
9be7db547a Add a game_state argument to decode_ui()
Some games would like a way to check that the parameters in the encoded
UI string are consistent with the game parameters.  Since this might
depend on the current state of the game (this being what changed_state()
is for), implement this by adding a game_state parameter to decode_ui().
Nothing currently uses it, though Guess usefully could.
2023-04-08 20:08:16 +01:00
3b9cafa09f Fall back to <math.h> if <tgmath.h> doesn't work.
This fixes a build failure introduced by commit 2e48ce132e011e8
yesterday.

When I saw that commit I expected the most likely problem would be in
the NestedVM build, which is currently the thing with the most most
out-of-date C implementation. And indeed the NestedVM toolchain
doesn't have <tgmath.h> - but much more surprisingly, our _Windows_
builds failed too, with a compile error inside <tgmath.h> itself!

I haven't looked closely into the problem yet. Our Windows builds are
done with clang, which comes with its own <tgmath.h> superseding the
standard Windows one. So you'd _hope_ that clang could make sense of
its own header! But perhaps the problem is that this is an unusual
compile mode and hasn't been tested.

My fix is to simply add a cmake check for <tgmath.h> - which doesn't
just check the file's existence, it actually tries compiling a file
that #includes it, so it will detect 'file exists but is mysteriously
broken' just as easily as 'not there at all'. So this makes the builds
start working again, precisely on Ben's theory of opportunistically
using <tgmath.h> where possible and falling back to <math.h>
otherwise.

It looks ugly, though! I'm half tempted to make a new header file
whose job is to include a standard set of system headers, just so that
that nasty #ifdef doesn't have to sit at the top of almost all the
source files. But for the moment this at least gets the build working
again.
2023-04-06 07:08:04 +01:00
2e48ce132e Replace <math.h> with <tgmath.h> throughout
C89 provided only double-precision mathematical functions (sin() etc),
and so despite using single-precision elsewhere, those are what Puzzles
has traditionally used.  C99 introduced single-precision equivalents
(sinf() etc), and I hope it's been long enough that we can safely use
them.  Maybe they'll even be faster.

Rather than directly use the single-precision functions, though, we use
the magic macros from <tgmath.h> that automatically choose the precision
of mathematical functions based on their arguments.  This has the
advantage that we only need to change which header we include, and thus
that we can switch back again if some platform has trouble with the new
header.
2023-04-04 21:43:25 +01:00
6dac51795e Add an environment variable to control initial cursor visibility
If you define PUZZLES_INITIAL_CURSOR=y, puzzles that have a keyboard
cursor will default to making it visible rather than invisible at the
start of a new game.  Behaviour is otherwise the same, so mouse actions
will cause the cursor to vanish and keyboard actions will cause it to
appear.  It's just the default that has changed.

The purpose of this is for use on devices and platforms where the
primary or only means of interaction is keyboard-based.  In those cases,
starting with the keyboard cursor invisible is weird and a bit
confusing.
2023-03-22 16:58:22 +00:00
9394e9c74b Tighten grid-size limit in Mines
Mines uses random_upto() to decide where to place mines, and
random_upto() takes a maximum limit of 2^28-1, so limit the number of
grid squares to that (or INT_MAX if someone's still trying to build on
a 16-bit system).

This avoids an assertion failure: "random_upto: Assertion `bits < 32'
failed." which can be demonstrated by this save file:

SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
VERSION :1:1
GAME    :5:Mines
PARAMS  :5:18090
CPARAMS :5:18090
DESC    :11:r9,u,MEdff6
UI      :2:D0
TIME    :1:0
NSTATES :1:2
STATEPOS:1:2
MOVE    :4:O2,1
2023-02-15 14:07:59 +00:00
49841bd0fc Mines: Add assertions to range-check conversions to short
I think these should be adequately guarded by the new restrictions on
grid size, but I'd prefer to be sure.
2023-02-05 21:00:00 +00:00
c0e08f3087 Limit width and height to SHRT_MAX in Mines
Mines' "struct set" stores co-ordinates within the grid in a pair of
shorts, which leads to very bad behaviour (including heap-based buffer
overruns) if the grid is bigger than SHRT_MAX in either dimension.  So
now we don't allow that.

The overrun can be demonstrated by loading this save file, though the
precise crash is quite variable.  In particular, you seem to get
better crashes if the file doesn't have a trailing newline.

SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
PARAMS  :5:06000
CPARAMS :7:6x60000
NSTATES :1:3
STATEPOS:1:2
MOVE    :5:C0,00
GAME    :5:Mines
DESC    :22:r8,u,00000000000000000
MOVE    ::
2023-02-05 20:59:59 +00:00
2a9be2b89d Mines: Don't check if the player has won if they've already lost
It can't happen in normal play, but if a save file had a "C" (clear
around) move that set off a mine, Mines could end up hitting an
assertion failure, "ncovered >= nmines".  This was because it would
check if the player had won by counting covered squares and mines, and
of course an uncovered mine is no longer a covered square but is still a
mine.

Since winning after you're dead isn't possible (at least in Mines), we
now skip the check entirely if the player has already died.

This save file demonstrates the problem:

SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
GAME    :5:Mines
PARAMS  :1:7
CPARAMS :1:7
DESC    :22:r31,u,0000C000d0000020
NSTATES :1:2
STATEPOS:1:1
MOVE    :4:C6,2
2023-02-01 20:32:26 +00:00
1736445518 Mines: forbid moves that flag or unflag an exposed square
interpret_move() couldn't generate them, but execute_move() also needs
to forbid them to defend against corrupt save files.  I don't think this
actually caused any crashes, but it did cause unexpected "1" squares not
adjacent to mines.
2023-02-01 20:29:45 +00:00
789e11f8f8 Remove various unused game functions
If can_configure is false, then the game's configure() and
custom_params() functions will never be called.  If can_solve is false,
solve() will never be called.  If can_format_as_text_ever is false,
can_format_as_text_now() and text_format() will never be called.  If
can_print is false, print_size() and print() will never be called.  If
is_timed is false, timing_state() will never be called.

In each case, almost all puzzles provided a function nonetheless.  I
think this is because in Puzzles' early history there was no "game"
structure, so the functions had to be present for linking to work.  But
now that everything indirects through the "game" structure, unused
functions can be left unimplemented and the corresponding pointers set
to NULL.

So now where the flags mentioned above are false, the corresponding
functions are omitted and the function pointers in the "game" structures
are NULL.
2023-01-31 23:25:05 +00:00
75e8a1a9ca Limit number of mines in Mines game description
Without this, it's possible to specify a description that has more
mines than there are places on the board to place them, which
eventually leads to a division by zero.  This can be demonstrated by
entering a game description of "3:r8,u," and then clicking anywhere on
the board.
2023-01-28 23:12:52 +00:00
28671e76b7 Don't segfault on premature solve moves in Mines
If a save file contained a solve move as the first move, Mines would
dereference a null pointer trying to look up the (at that point
undetermined) mine locations.  Now execute_move() politely returns
NULL instead.

This save file demonstrates the problem:

SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
VERSION :1:1
GAME    :5:Mines
PARAMS  :5:3x3n0
CPARAMS :5:3x3n0
DESC    :127:r0,u,7a142789cabddc3fc4dcb7d2baa4a4937b33c9613ea870ac098e217981ad339930af585557d62048ea745d05b01475d9699596b394cc0adeebf0440a02
UI      :2:D0
TIME    :1:0
NSTATES :1:2
STATEPOS:1:2
SOLVE   :1:S
2023-01-28 19:34:28 +00:00
5bd02f982a Mines: No moving once you're dead!
If a Mines save file contains a move after the player has already
died, this can lead to an assertion failure once there are more mines
that covered squares.  Better to just reject any move after the
player's died.
2023-01-15 16:24:27 +00:00
9e2e0692ed Also check for tiny grids in Mines
A zero-size grid isn't acceptable even if someone has generated it for
us.
2023-01-15 16:24:27 +00:00
5cc9bfb811 Last-ditch maximum size limit for Mines
This makes sure that width * height <= INT_MAX, which it rather needs
to be.  Also a similar check in decode_params when defaulting the
number of mines.
2023-01-15 16:24:27 +00:00
a3310ab857 New backend function: current_key_label()
This provides a way for the front end to ask how a particular key should
be labelled right now (specifically, for a given game_state and
game_ui).  This is useful on feature phones where it's conventional to
put a small caption above each soft key indicating what it currently
does.

The function currently provides labels only for CURSOR_SELECT and
CURSOR_SELECT2.  This is because these are the only keys that need
labelling on KaiOS.

The concept of labelling keys also turns up in the request_keys() call,
but there are quite a few differences.  The labels returned by
current_key_label() are dynamic and likely to vary with each move, while
the labels provided by request_keys() are constant for a given
game_params.  Also, the keys returned by request_keys() don't generally
include CURSOR_SELECT and CURSOR_SELECT2, because those aren't necessary
on platforms with pointing devices.  It might be possible to provide a
unified API covering both of this, but I think it would be quite
difficult to work with.

Where a key is to be unlabelled, current_key_label() is expected to
return an empty string.  This leaves open the possibility of NULL
indicating a fallback to button2label or the label specified by
request_keys() in the future.

It's tempting to try to implement current_key_label() by calling
interpret_move() and parsing its output.  This doesn't work for two
reasons.  One is that interpret_move() is entitled to modify the
game_ui, and there isn't really a practical way to back those changes
out.  The other is that the information returned by interpret_move()
isn't sufficient to generate a label.  For instance, in many puzzles it
generates moves that toggle the state of a square, but we want the label
to reflect which state the square will be toggled to.  The result is
that I've generally ended up pulling bits of code from interpret_move()
and execute_move() together to implement current_key_label().

Alongside the back-end function, there's a midend_current_key_label()
that's a thin wrapper around the back-end function.  It just adds an
assertion about which key's being requested and a default null
implementation so that back-ends can avoid defining the function if it
will do nothing useful.
2022-12-09 20:48:30 +00:00
0b36c01639 mines: Ensure highlights don't vanish at small tile sizes
The highlights for covered squares now have a minimum width of 1 pixel,
which means that Mines is comfortably playabale down to about 8 pixel
tilesize, below which the numbers become unreadable.
2022-11-25 13:29:04 +00:00
387d323dd8 Mines: fix a typo in a comment.
A sharp-eyed user just pointed it out.
2022-06-12 08:00:08 +01:00
c0da615a93 Centralise initial clearing of the puzzle window.
I don't know how I've never thought of this before! Pretty much every
game in this collection has to have a mechanism for noticing when
game_redraw is called for the first time on a new drawstate, and if
so, start by covering the whole window with a filled rectangle of the
background colour. This is a pain for implementers, and also awkward
because the drawstate often has to _work out_ its own pixel size (or
else remember it from when its size method was called).

The backends all do that so that the frontends don't have to guarantee
anything about the initial window contents. But that's a silly
tradeoff to begin with (there are way more backends than frontends, so
this _adds_ work rather than saving it), and also, in this code base
there's a standard way to handle things you don't want to have to do
in every backend _or_ every frontend: do them just once in the midend!

So now that rectangle-drawing operation happens in midend_redraw, and
I've been able to remove it from almost every puzzle. (A couple of
puzzles have other approaches: Slant didn't have a rectangle-draw
because it handles even the game borders using its per-tile redraw
function, and Untangle clears the whole window on every redraw
_anyway_ because it would just be too confusing not to.)

In some cases I've also been able to remove the 'started' flag from
the drawstate. But in many cases that has to stay because it also
triggers drawing of static display furniture other than the
background.
2021-04-25 13:07:59 +01:00
78bc9ea7f7 Add method for frontends to query the backend's cursor location.
The Rockbox frontend allows games to be displayed in a "zoomed-in"
state targets with small displays. Currently we use a modal interface
-- a "viewing" mode in which the cursor keys are used to pan around
the rendered bitmap; and an "interaction" mode that actually sends
keys to the game.

This commit adds a midend_get_cursor_location() function to allow the
frontend to retrieve the backend's cursor location or other "region of
interest" -- such as the player location in Cube or Inertia.

With this information, the Rockbox frontend can now intelligently
follow the cursor around in the zoomed-in state, eliminating the need
for a modal interface.
2020-12-07 19:40:06 +00:00
d71ac73d8a Mines: add validation for negative mine count.
If this gets through validation, it causes an infinite loop after
gameplay begins.
2020-03-17 18:12:33 +00:00
5f5b284c0b Use C99 bool within source modules.
This is the main bulk of this boolification work, but although it's
making the largest actual change, it should also be the least
disruptive to anyone interacting with this code base downstream of me,
because it doesn't modify any interface between modules: all the
inter-module APIs were updated one by one in the previous commits.
This just cleans up the code within each individual source file to use
bool in place of int where I think that makes things clearer.
2018-11-13 21:48:24 +00:00
a550ea0a47 Replace TRUE/FALSE with C99 true/false throughout.
This commit removes the old #defines of TRUE and FALSE from puzzles.h,
and does a mechanical search-and-replace throughout the code to
replace them with the C99 standard lowercase spellings.
2018-11-13 21:48:24 +00:00
a76d269cf2 Adopt C99 bool in the game backend API.
encode_params, validate_params and new_desc now take a bool parameter;
fetch_preset, can_format_as_text_now and timing_state all return bool;
and the data fields is_timed, wants_statusbar and can_* are all bool.
All of those were previously typed as int, but semantically boolean.

This commit changes the API declarations in puzzles.h, updates all the
games to match (including the unfinisheds), and updates the developer
docs as well.
2018-11-13 21:34:42 +00:00
60a929a250 Add a request_keys() function with a midend wrapper.
This function gives the front end a way to find out what keys the back
end requires; and as such it is mostly useful for ports without a
keyboard. It is based on changes originally found in Chris Boyle's
Android port, though some modifications were needed to make it more
flexible.
2018-04-22 17:04:50 +01:00
a58c1b216b Make the code base clean under -Wwrite-strings.
I've also added that warning option and -Werror to the build script,
so that I'll find out if I break this property in future.
2017-10-01 16:35:40 +01:00
b3243d7504 Return error messages as 'const char *', not 'char *'.
They're never dynamically allocated, and are almost always string
literals, so const is more appropriate.
2017-10-01 16:34:41 +01:00
de67801b0f Use a proper union in struct config_item.
This allows me to use different types for the mutable, dynamically
allocated string value in a C_STRING control and the fixed constant
list of option names in a C_CHOICES.
2017-10-01 16:34:41 +01:00
eeb2db283d New name UI_UPDATE for interpret_move's return "".
Now midend.c directly tests the returned pointer for equality to this
value, instead of checking whether it's the empty string.

A minor effect of this is that games may now return a dynamically
allocated empty string from interpret_move() and treat it as just
another legal move description. But I don't expect anyone to be
perverse enough to actually do that! The main purpose is that it
avoids returning a string literal from a function whose return type is
a pointer to _non-const_ char, i.e. we are now one step closer to
being able to make this code base clean under -Wwrite-strings.
2017-10-01 15:18:14 +01:00
afc2134d26 Mines: show the number of safe squares left, if it's small.
This is intended to make life easier for the _really_ dense grids in
which the generator algorithm falls back to a bare clearing, a tightly
packed section round the edges, and a fringe of deductions required in
between.

In that situation, you can deduce _in principle_ from the remaining-
mines counter that there are (say) one, or two, squares left to be
uncovered before everything remaining has to be a mine. And often the
game will require that deduction in order to solve it all by pure
logic. But actually doing it requires counting up the huge number of
covered squares in an irregularly shaped area and subtracting the mine
count in the status line, which is a real pain.

In fact, people failing to do that are the biggest source of (wrong)
bug reports about Mines games having no solution, so with any luck
this will make my own life easier.
2017-09-04 19:50:43 +01:00
a7dc17c425 Rework the preset menu system to permit submenus.
To do this, I've completely replaced the API between mid-end and front
end, so any downstream front end maintainers will have to do some
rewriting of their own (sorry). I've done the necessary work in all
five of the front ends I keep in-tree here - Windows, GTK, OS X,
Javascript/Emscripten, and Java/NestedVM - and I've done it in various
different styles (as each front end found most convenient), so that
should provide a variety of sample code to show downstreams how, if
they should need it.

I've left in the old puzzle back-end API function to return a flat
list of presets, so for the moment, all the puzzle backends are
unchanged apart from an extra null pointer appearing in their
top-level game structure. In a future commit I'll actually use the new
feature in a puzzle; perhaps in the further future it might make sense
to migrate all the puzzles to the new API and stop providing back ends
with two alternative ways of doing things, but this seemed like enough
upheaval for one day.
2017-04-26 21:51:23 +01:00
251b21c418 Giant const patch of doom: add a 'const' to every parameter in every
puzzle backend function which ought to have it, and propagate those
consts through to per-puzzle subroutines as needed.

I've recently had to do that to a few specific parameters which were
being misused by particular puzzles (r9657, r9830), which suggests
that it's probably a good idea to do the whole lot pre-emptively
before the next such problem shows up.

[originally from svn r9832]
[r9657 == 3b250baa02a7332510685948bf17576c397b8ceb]
[r9830 == 0b93de904a98f119b1a95d3a53029f1ed4bfb9b3]
2013-04-13 10:37:32 +00:00
0b93de904a Add 'const' to the game_params arguments in validate_desc and
new_desc. Oddities in the 'make test' output brought to my attention
that a few puzzles have been modifying their input game_params for
various reasons; they shouldn't do that, because that's the
game_params held permanently by the midend and it will affect
subsequent game generations if they modify it. So now those arguments
are const, and all the games which previously modified their
game_params now take a copy and modify that instead.

[originally from svn r9830]
2013-04-12 17:11:49 +00:00
3b250baa02 New rule: interpret_move() is passed a pointer to the game_drawstate
basically just so that it can divide mouse coordinates by the tile
size, but is definitely not expected to _write_ to it, and it hadn't
previously occurred to me that anyone might try. Therefore,
interpret_move() now gets a pointer to a _const_ game_drawstate
instead of a writable one.

All existing puzzles cope fine with this API change (as long as the
new const qualifier is also added to a couple of subfunctions to which
interpret_move delegates work), except for the just-committed Undead,
which somehow had ds->ascii and ui->ascii the wrong way round but is
otherwise unproblematic.

[originally from svn r9657]
2012-09-09 18:40:12 +00:00
6567260eb0 Vary the behaviour of Mines's solve function depending on whether the
user is already in the 'dead' state when they press it. If so, we
reveal the rest of the mines in the grid as if it were the Windows
Minesweeper 'you lose' display, which provides information showing
what the user got wrong. (Otherwise they have to repeatedly flick back
and forth between Solve and Undo if they want to work out which flag
they placed wrongly.)

If you press Solve while alive, however, the existing behaviour
remains unchanged.

(This feature was suggested by Clive Jones a couple of weeks after I
first wrote Mines, and I've finally got round to doing it!)

[originally from svn r9561]
2012-06-10 07:20:18 +00:00
73daff3937 Changed my mind about midend_is_solved: I've now reprototyped it as
midend_status(), and given it three return codes for win, (permanent)
loss and game-still-in-play. Depending on what the front end wants to
use it for, it may find any or all of these three states worth
distinguishing from each other.

(I suppose a further enhancement might be to add _non_-permanent loss
as a fourth distinct status, to describe situations in which you can't
play further without pressing Undo but doing so is not completely
pointless. That might reasonably include dead-end situations in Same
Game and Pegs, and blown-self-up situations in Mines and Inertia.
However, I haven't done this at present.)

[originally from svn r9179]
2011-06-19 13:43:35 +00:00
2efc77d2fd Fix warnings generated by gcc 4.6.0 about variables set but not
thereafter read. Most of these changes are just removal of pointless
stuff or trivial reorganisations; one change is actually substantive,
and fixes a bug in Keen's clue selection (the variable 'bad' was
unreferenced not because I shouldn't have set it, but because I
_should_ have referenced it!).

[originally from svn r9164]
2011-05-04 18:22:14 +00:00
980880be1f Add a function to every game backend which indicates whether a game
state is in a solved position, and a midend function wrapping it.

(Or, at least, a situation in which further play is pointless. The
point is, given that game state, would it be a good idea for a front
end that does that sort of thing to proactively provide the option to
start a fresh game?)

[originally from svn r9140]
2011-04-02 16:19:12 +00:00
dfb8fa2e92 Redo Mines and Inertia's mine graphics using an actual circle rather
than an approximating octagon, to improve the look when zoomed to
high resolution.

[originally from svn r8646]
2009-09-13 13:08:34 +00:00
f20847354c Patches from James H to add or improve arrow-key-driven cursors for
some puzzles. (Light Up's and Net's are merely polished a bit, but
Mines acquires a new one.)

[originally from svn r8402]
2009-01-08 18:28:32 +00:00
a7431c0b7c New infrastructure feature. Games are now permitted to be
_conditionally_ able to format the current puzzle as text to be sent
to the clipboard. For instance, if a game were to support playing on
a square grid and on other kinds of grid such as hexagonal, then it
might reasonably feel that only the former could be sensibly
rendered in ASCII art; so it can now arrange for the "Copy" menu
item to be greyed out depending on the game_params.

To do this I've introduced a new backend function
(can_format_as_text_now()), and renamed the existing static backend
field "can_format_as_text" to "can_format_as_text_ever". The latter
will cause compile errors for anyone maintaining a third-party front
end; if any such person is reading this, I apologise to them for the
inconvenience, but I did do it deliberately so that they'd know to
update their front end.

As yet, no checked-in game actually uses this feature; all current
games can still either copy always or copy never.

[originally from svn r8161]
2008-09-06 09:27:56 +00:00
15f70f527a Dariusz Olszewski's changes to support compiling for PocketPC. This
is mostly done with ifdefs in windows.c; so mkfiles.pl generates a
new makefile (Makefile.wce) and Recipe enables it, but it's hardly
any different from Makefile.vc apart from a few definitions at the
top of the files.

Currently the PocketPC build is not enabled in the build script, but
with any luck I'll be able to do so reasonably soon.

[originally from svn r7337]
2007-02-26 20:35:47 +00:00
7b1f7d3e01 HTML Help support for Puzzles, with the same kind of automatic
fallback behaviour as PuTTY's support.

[originally from svn r7009]
2006-12-24 15:56:47 +00:00
fe514e9374 Mines's error signalling is highly asymmetric: if you erroneously
believe a square to be empty, you find out instantly and lethally,
but if you erroneously believe a square to be full you can
occasionally (when it doesn't cause a complementary square to be
assumed empty) not notice until you find at the very end of the game
that you're one mine heavy. To help with this, here's an error
highlighting patch: any number square surrounded by an excess of
flags will now light up red. This should be an unintrusive change,
because it will never happen unless you make a mistake.

[originally from svn r6580]
2006-02-20 19:51:50 +00:00