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puzzles/mines.c
Simon Tatham 6b9e690c89 Initial checkin of my Minesweeper clone, which uses a solver during 
grid generation to arrange a mine layout that never requires guessing.

[originally from svn r5859]
2005-05-30 10:08:27 +00:00

2649 lines
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/*
* mines.c: Minesweeper clone with sophisticated grid generation.
*
* Still TODO:
*
* - possibly disable undo? Or alternatively mark game states as
* `cheated', although that's horrid.
* + OK. Rather than _disabling_ undo, we have a hook callable
* in the game backend which is called before we do an undo.
* That hook can talk to the game_ui and set the cheated flag,
* and then make_move can avoid setting the `won' flag after that.
*
* - delay game description generation until first click
* + do we actually _need_ to do this? Hmm.
* + it's a perfectly good puzzle game without
* + but it might be useful when we start timing, since it
* ensures the user is really paying attention.
*
* - timer
*
* - question marks (arrgh, preferences?)
*
* - sensible parameter constraints
* + 30x16: 191 mines just about works if rather slowly, 192 is
* just about doom (the latter corresponding to a density of
* exactly 1 in 2.5)
* + 9x9: 45 mines works - over 1 in 2! 50 seems a bit slow.
* + it might not be feasible to work out the exact limit
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include "tree234.h"
#include "puzzles.h"
enum {
COL_BACKGROUND,
COL_1, COL_2, COL_3, COL_4, COL_5, COL_6, COL_7, COL_8,
COL_MINE, COL_BANG, COL_CROSS, COL_FLAG, COL_FLAGBASE, COL_QUERY,
COL_HIGHLIGHT, COL_LOWLIGHT,
NCOLOURS
};
#define TILE_SIZE 20
#define BORDER (TILE_SIZE * 3 / 2)
#define HIGHLIGHT_WIDTH 2
#define OUTER_HIGHLIGHT_WIDTH 3
#define COORD(x) ( (x) * TILE_SIZE + BORDER )
#define FROMCOORD(x) ( ((x) - BORDER + TILE_SIZE) / TILE_SIZE - 1 )
#define FLASH_FRAME 0.13F
struct game_params {
int w, h, n;
int unique;
};
struct game_state {
int w, h, n, dead, won;
char *mines; /* real mine positions */
char *grid; /* player knowledge */
/*
* Each item in the `grid' array is one of the following values:
*
* - 0 to 8 mean the square is open and has a surrounding mine
* count.
*
* - -1 means the square is marked as a mine.
*
* - -2 means the square is unknown.
*
* - -3 means the square is marked with a question mark
* (FIXME: do we even want to bother with this?).
*
* - 64 means the square has had a mine revealed when the game
* was lost.
*
* - 65 means the square had a mine revealed and this was the
* one the player hits.
*
* - 66 means the square has a crossed-out mine because the
* player had incorrectly marked it.
*/
};
static game_params *default_params(void)
{
game_params *ret = snew(game_params);
ret->w = ret->h = 9;
ret->n = 10;
ret->unique = TRUE;
return ret;
}
static int game_fetch_preset(int i, char **name, game_params **params)
{
game_params *ret;
char str[80];
static const struct { int w, h, n; } values[] = {
{9, 9, 10},
{16, 16, 40},
{30, 16, 99},
};
if (i < 0 || i >= lenof(values))
return FALSE;
ret = snew(game_params);
ret->w = values[i].w;
ret->h = values[i].h;
ret->n = values[i].n;
ret->unique = TRUE;
sprintf(str, "%dx%d, %d mines", ret->w, ret->h, ret->n);
*name = dupstr(str);
*params = ret;
return TRUE;
}
static void free_params(game_params *params)
{
sfree(params);
}
static game_params *dup_params(game_params *params)
{
game_params *ret = snew(game_params);
*ret = *params; /* structure copy */
return ret;
}
static void decode_params(game_params *params, char const *string)
{
char const *p = string;
params->w = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
if (*p == 'x') {
p++;
params->h = atoi(p);
while (*p && isdigit((unsigned char)*p)) p++;
} else {
params->h = params->w;
}
if (*p == 'n') {
p++;
params->n = atoi(p);
while (*p && (*p == '.' || isdigit((unsigned char)*p))) p++;
} else {
params->n = params->w * params->h / 10;
}
while (*p) {
if (*p == 'a') {
p++;
params->unique = FALSE;
} else
p++; /* skip any other gunk */
}
}
static char *encode_params(game_params *params, int full)
{
char ret[400];
int len;
len = sprintf(ret, "%dx%d", params->w, params->h);
/*
* Mine count is a generation-time parameter, since it can be
* deduced from the mine bitmap!
*/
if (full)
len += sprintf(ret+len, "n%d", params->n);
if (full && !params->unique)
ret[len++] = 'a';
assert(len < lenof(ret));
ret[len] = '\0';
return dupstr(ret);
}
static config_item *game_configure(game_params *params)
{
config_item *ret;
char buf[80];
ret = snewn(5, config_item);
ret[0].name = "Width";
ret[0].type = C_STRING;
sprintf(buf, "%d", params->w);
ret[0].sval = dupstr(buf);
ret[0].ival = 0;
ret[1].name = "Height";
ret[1].type = C_STRING;
sprintf(buf, "%d", params->h);
ret[1].sval = dupstr(buf);
ret[1].ival = 0;
ret[2].name = "Mines";
ret[2].type = C_STRING;
sprintf(buf, "%d", params->n);
ret[2].sval = dupstr(buf);
ret[2].ival = 0;
ret[3].name = "Ensure solubility";
ret[3].type = C_BOOLEAN;
ret[3].sval = NULL;
ret[3].ival = params->unique;
ret[4].name = NULL;
ret[4].type = C_END;
ret[4].sval = NULL;
ret[4].ival = 0;
return ret;
}
static game_params *custom_params(config_item *cfg)
{
game_params *ret = snew(game_params);
ret->w = atoi(cfg[0].sval);
ret->h = atoi(cfg[1].sval);
ret->n = atoi(cfg[2].sval);
ret->unique = cfg[3].ival;
return ret;
}
static char *validate_params(game_params *params)
{
if (params->w <= 0 && params->h <= 0)
return "Width and height must both be greater than zero";
if (params->w <= 0)
return "Width must be greater than zero";
if (params->h <= 0)
return "Height must be greater than zero";
/*
* FIXME: Need more constraints here. Not sure what the
* sensible limits for Minesweeper actually are. The limits
* probably ought to change, however, depending on uniqueness.
*/
return NULL;
}
/* ----------------------------------------------------------------------
* Minesweeper solver, used to ensure the generated grids are
* solvable without having to take risks.
*/
/*
* Count the bits in a word. Only needs to cope with 16 bits.
*/
static int bitcount16(int word)
{
word = ((word & 0xAAAA) >> 1) + (word & 0x5555);
word = ((word & 0xCCCC) >> 2) + (word & 0x3333);
word = ((word & 0xF0F0) >> 4) + (word & 0x0F0F);
word = ((word & 0xFF00) >> 8) + (word & 0x00FF);
return word;
}
/*
* We use a tree234 to store a large number of small localised
* sets, each with a mine count. We also keep some of those sets
* linked together into a to-do list.
*/
struct set {
short x, y, mask, mines;
int todo;
struct set *prev, *next;
};
static int setcmp(void *av, void *bv)
{
struct set *a = (struct set *)av;
struct set *b = (struct set *)bv;
if (a->y < b->y)
return -1;
else if (a->y > b->y)
return +1;
else if (a->x < b->x)
return -1;
else if (a->x > b->x)
return +1;
else if (a->mask < b->mask)
return -1;
else if (a->mask > b->mask)
return +1;
else
return 0;
}
struct setstore {
tree234 *sets;
struct set *todo_head, *todo_tail;
};
static struct setstore *ss_new(void)
{
struct setstore *ss = snew(struct setstore);
ss->sets = newtree234(setcmp);
ss->todo_head = ss->todo_tail = NULL;
return ss;
}
/*
* Take two input sets, in the form (x,y,mask). Munge the first by
* taking either its intersection with the second or its difference
* with the second. Return the new mask part of the first set.
*/
static int setmunge(int x1, int y1, int mask1, int x2, int y2, int mask2,
int diff)
{
/*
* Adjust the second set so that it has the same x,y
* coordinates as the first.
*/
if (abs(x2-x1) >= 3 || abs(y2-y1) >= 3) {
mask2 = 0;
} else {
while (x2 > x1) {
mask2 &= ~(4|32|256);
mask2 <<= 1;
x2--;
}
while (x2 < x1) {
mask2 &= ~(1|8|64);
mask2 >>= 1;
x2++;
}
while (y2 > y1) {
mask2 &= ~(64|128|256);
mask2 <<= 3;
y2--;
}
while (y2 < y1) {
mask2 &= ~(1|2|4);
mask2 >>= 3;
y2++;
}
}
/*
* Invert the second set if `diff' is set (we're after A &~ B
* rather than A & B).
*/
if (diff)
mask2 ^= 511;
/*
* Now all that's left is a logical AND.
*/
return mask1 & mask2;
}
static void ss_add_todo(struct setstore *ss, struct set *s)
{
if (s->todo)
return; /* already on it */
#ifdef SOLVER_DIAGNOSTICS
printf("adding set on todo list: %d,%d %03x %d\n",
s->x, s->y, s->mask, s->mines);
#endif
s->prev = ss->todo_tail;
if (s->prev)
s->prev->next = s;
else
ss->todo_head = s;
ss->todo_tail = s;
s->next = NULL;
s->todo = TRUE;
}
static void ss_add(struct setstore *ss, int x, int y, int mask, int mines)
{
struct set *s;
assert(mask != 0);
/*
* Normalise so that x and y are genuinely the bounding
* rectangle.
*/
while (!(mask & (1|8|64)))
mask >>= 1, x++;
while (!(mask & (1|2|4)))
mask >>= 3, y++;
/*
* Create a set structure and add it to the tree.
*/
s = snew(struct set);
s->x = x;
s->y = y;
s->mask = mask;
s->mines = mines;
s->todo = FALSE;
if (add234(ss->sets, s) != s) {
/*
* This set already existed! Free it and return.
*/
sfree(s);
return;
}
/*
* We've added a new set to the tree, so put it on the todo
* list.
*/
ss_add_todo(ss, s);
}
static void ss_remove(struct setstore *ss, struct set *s)
{
struct set *next = s->next, *prev = s->prev;
#ifdef SOLVER_DIAGNOSTICS
printf("removing set %d,%d %03x\n", s->x, s->y, s->mask);
#endif
/*
* Remove s from the todo list.
*/
if (prev)
prev->next = next;
else if (s == ss->todo_head)
ss->todo_head = next;
if (next)
next->prev = prev;
else if (s == ss->todo_tail)
ss->todo_tail = prev;
s->todo = FALSE;
/*
* Remove s from the tree.
*/
del234(ss->sets, s);
/*
* Destroy the actual set structure.
*/
sfree(s);
}
/*
* Return a dynamically allocated list of all the sets which
* overlap a provided input set.
*/
static struct set **ss_overlap(struct setstore *ss, int x, int y, int mask)
{
struct set **ret = NULL;
int nret = 0, retsize = 0;
int xx, yy;
for (xx = x-3; xx < x+3; xx++)
for (yy = y-3; yy < y+3; yy++) {
struct set stmp, *s;
int pos;
/*
* Find the first set with these top left coordinates.
*/
stmp.x = xx;
stmp.y = yy;
stmp.mask = 0;
if (findrelpos234(ss->sets, &stmp, NULL, REL234_GE, &pos)) {
while ((s = index234(ss->sets, pos)) != NULL &&
s->x == xx && s->y == yy) {
/*
* This set potentially overlaps the input one.
* Compute the intersection to see if they
* really overlap, and add it to the list if
* so.
*/
if (setmunge(x, y, mask, s->x, s->y, s->mask, FALSE)) {
/*
* There's an overlap.
*/
if (nret >= retsize) {
retsize = nret + 32;
ret = sresize(ret, retsize, struct set *);
}
ret[nret++] = s;
}
pos++;
}
}
}
ret = sresize(ret, nret+1, struct set *);
ret[nret] = NULL;
return ret;
}
/*
* Get an element from the head of the set todo list.
*/
static struct set *ss_todo(struct setstore *ss)
{
if (ss->todo_head) {
struct set *ret = ss->todo_head;
ss->todo_head = ret->next;
if (ss->todo_head)
ss->todo_head->prev = NULL;
else
ss->todo_tail = NULL;
ret->next = ret->prev = NULL;
ret->todo = FALSE;
return ret;
} else {
return NULL;
}
}
struct squaretodo {
int *next;
int head, tail;
};
static void std_add(struct squaretodo *std, int i)
{
if (std->tail >= 0)
std->next[std->tail] = i;
else
std->head = i;
std->tail = i;
std->next[i] = -1;
}
static void known_squares(int w, int h, struct squaretodo *std, char *grid,
int (*open)(void *ctx, int x, int y), void *openctx,
int x, int y, int mask, int mine)
{
int xx, yy, bit;
bit = 1;
for (yy = 0; yy < 3; yy++)
for (xx = 0; xx < 3; xx++) {
if (mask & bit) {
int i = (y + yy) * w + (x + xx);
/*
* It's possible that this square is _already_
* known, in which case we don't try to add it to
* the list twice.
*/
if (grid[i] == -2) {
if (mine) {
grid[i] = -1; /* and don't open it! */
} else {
grid[i] = open(openctx, x + xx, y + yy);
assert(grid[i] != -1); /* *bang* */
}
std_add(std, i);
}
}
bit <<= 1;
}
}
/*
* This is data returned from the `perturb' function. It details
* which squares have become mines and which have become clear. The
* solver is (of course) expected to honourably not use that
* knowledge directly, but to efficently adjust its internal data
* structures and proceed based on only the information it
* legitimately has.
*/
struct perturbation {
int x, y;
int delta; /* +1 == become a mine; -1 == cleared */
};
struct perturbations {
int n;
struct perturbation *changes;
};
/*
* Main solver entry point. You give it a grid of existing
* knowledge (-1 for a square known to be a mine, 0-8 for empty
* squares with a given number of neighbours, -2 for completely
* unknown), plus a function which you can call to open new squares
* once you're confident of them. It fills in as much more of the
* grid as it can.
*
* Return value is:
*
* - -1 means deduction stalled and nothing could be done
* - 0 means deduction succeeded fully
* - >0 means deduction succeeded but some number of perturbation
* steps were required; the exact return value is the number of
* perturb calls.
*/
static int minesolve(int w, int h, int n, char *grid,
int (*open)(void *ctx, int x, int y),
struct perturbations *(*perturb)(void *ctx, char *grid,
int x, int y, int mask),
void *ctx, random_state *rs)
{
struct setstore *ss = ss_new();
struct set **list;
struct squaretodo astd, *std = &astd;
int x, y, i, j;
int nperturbs = 0;
/*
* Set up a linked list of squares with known contents, so that
* we can process them one by one.
*/
std->next = snewn(w*h, int);
std->head = std->tail = -1;
/*
* Initialise that list with all known squares in the input
* grid.
*/
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
i = y*w+x;
if (grid[i] != -2)
std_add(std, i);
}
}
/*
* Main deductive loop.
*/
while (1) {
int done_something = FALSE;
struct set *s;
/*
* If there are any known squares on the todo list, process
* them and construct a set for each.
*/
while (std->head != -1) {
i = std->head;
#ifdef SOLVER_DIAGNOSTICS
printf("known square at %d,%d [%d]\n", i%w, i/w, grid[i]);
#endif
std->head = std->next[i];
if (std->head == -1)
std->tail = -1;
x = i % w;
y = i / w;
if (grid[i] >= 0) {
int dx, dy, mines, bit, val;
#ifdef SOLVER_DIAGNOSTICS
printf("creating set around this square\n");
#endif
/*
* Empty square. Construct the set of non-known squares
* around this one, and determine its mine count.
*/
mines = grid[i];
bit = 1;
val = 0;
for (dy = -1; dy <= +1; dy++) {
for (dx = -1; dx <= +1; dx++) {
#ifdef SOLVER_DIAGNOSTICS
printf("grid %d,%d = %d\n", x+dx, y+dy, grid[i+dy*w+dx]);
#endif
if (x+dx < 0 || x+dx >= w || y+dy < 0 || y+dy >= h)
/* ignore this one */;
else if (grid[i+dy*w+dx] == -1)
mines--;
else if (grid[i+dy*w+dx] == -2)
val |= bit;
bit <<= 1;
}
}
if (val)
ss_add(ss, x-1, y-1, val, mines);
}
/*
* Now, whether the square is empty or full, we must
* find any set which contains it and replace it with
* one which does not.
*/
{
#ifdef SOLVER_DIAGNOSTICS
printf("finding sets containing known square %d,%d\n", x, y);
#endif
list = ss_overlap(ss, x, y, 1);
for (j = 0; list[j]; j++) {
int newmask, newmines;
s = list[j];
/*
* Compute the mask for this set minus the
* newly known square.
*/
newmask = setmunge(s->x, s->y, s->mask, x, y, 1, TRUE);
/*
* Compute the new mine count.
*/
newmines = s->mines - (grid[i] == -1);
/*
* Insert the new set into the collection,
* unless it's been whittled right down to
* nothing.
*/
if (newmask)
ss_add(ss, s->x, s->y, newmask, newmines);
/*
* Destroy the old one; it is actually obsolete.
*/
ss_remove(ss, s);
}
sfree(list);
}
/*
* Marking a fresh square as known certainly counts as
* doing something.
*/
done_something = TRUE;
}
/*
* Now pick a set off the to-do list and attempt deductions
* based on it.
*/
if ((s = ss_todo(ss)) != NULL) {
#ifdef SOLVER_DIAGNOSTICS
printf("set to do: %d,%d %03x %d\n", s->x, s->y, s->mask, s->mines);
#endif
/*
* Firstly, see if this set has a mine count of zero or
* of its own cardinality.
*/
if (s->mines == 0 || s->mines == bitcount16(s->mask)) {
/*
* If so, we can immediately mark all the squares
* in the set as known.
*/
#ifdef SOLVER_DIAGNOSTICS
printf("easy\n");
#endif
known_squares(w, h, std, grid, open, ctx,
s->x, s->y, s->mask, (s->mines != 0));
/*
* Having done that, we need do nothing further
* with this set; marking all the squares in it as
* known will eventually eliminate it, and will
* also permit further deductions about anything
* that overlaps it.
*/
continue;
}
/*
* Failing that, we now search through all the sets
* which overlap this one.
*/
list = ss_overlap(ss, s->x, s->y, s->mask);
for (j = 0; list[j]; j++) {
struct set *s2 = list[j];
int swing, s2wing, swc, s2wc;
/*
* Find the non-overlapping parts s2-s and s-s2,
* and their cardinalities.
*
* I'm going to refer to these parts as `wings'
* surrounding the central part common to both
* sets. The `s wing' is s-s2; the `s2 wing' is
* s2-s.
*/
swing = setmunge(s->x, s->y, s->mask, s2->x, s2->y, s2->mask,
TRUE);
s2wing = setmunge(s2->x, s2->y, s2->mask, s->x, s->y, s->mask,
TRUE);
swc = bitcount16(swing);
s2wc = bitcount16(s2wing);
/*
* If one set has more mines than the other, and
* the number of extra mines is equal to the
* cardinality of that set's wing, then we can mark
* every square in the wing as a known mine, and
* every square in the other wing as known clear.
*/
if (swc == s->mines - s2->mines ||
s2wc == s2->mines - s->mines) {
known_squares(w, h, std, grid, open, ctx,
s->x, s->y, swing,
(swc == s->mines - s2->mines));
known_squares(w, h, std, grid, open, ctx,
s2->x, s2->y, s2wing,
(s2wc == s2->mines - s->mines));
continue;
}
/*
* Failing that, see if one set is a subset of the
* other. If so, we can divide up the mine count of
* the larger set between the smaller set and its
* complement, even if neither smaller set ends up
* being immediately clearable.
*/
if (swc == 0 && s2wc != 0) {
/* s is a subset of s2. */
assert(s2->mines > s->mines);
ss_add(ss, s2->x, s2->y, s2wing, s2->mines - s->mines);
} else if (s2wc == 0 && swc != 0) {
/* s2 is a subset of s. */
assert(s->mines > s2->mines);
ss_add(ss, s->x, s->y, swing, s->mines - s2->mines);
}
}
sfree(list);
/*
* In this situation we have definitely done
* _something_, even if it's only reducing the size of
* our to-do list.
*/
done_something = TRUE;
} else if (n >= 0) {
/*
* We have nothing left on our todo list, which means
* all localised deductions have failed. Our next step
* is to resort to global deduction based on the total
* mine count. This is computationally expensive
* compared to any of the above deductions, which is
* why we only ever do it when all else fails, so that
* hopefully it won't have to happen too often.
*
* If you pass n<0 into this solver, that informs it
* that you do not know the total mine count, so it
* won't even attempt these deductions.
*/
int minesleft, squaresleft;
int nsets, setused[10], cursor;
/*
* Start by scanning the current grid state to work out
* how many unknown squares we still have, and how many
* mines are to be placed in them.
*/
squaresleft = 0;
minesleft = n;
for (i = 0; i < w*h; i++) {
if (grid[i] == -1)
minesleft--;
else if (grid[i] == -2)
squaresleft++;
}
#ifdef SOLVER_DIAGNOSTICS
printf("global deduction time: squaresleft=%d minesleft=%d\n",
squaresleft, minesleft);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
int v = grid[y*w+x];
if (v == -1)
putchar('*');
else if (v == -2)
putchar('?');
else if (v == 0)
putchar('-');
else
putchar('0' + v);
}
putchar('\n');
}
#endif
/*
* If there _are_ no unknown squares, we have actually
* finished.
*/
if (squaresleft == 0) {
assert(minesleft == 0);
break;
}
/*
* First really simple case: if there are no more mines
* left, or if there are exactly as many mines left as
* squares to play them in, then it's all easy.
*/
if (minesleft == 0 || minesleft == squaresleft) {
for (i = 0; i < w*h; i++)
if (grid[i] == -2)
known_squares(w, h, std, grid, open, ctx,
i % w, i / w, 1, minesleft != 0);
continue; /* now go back to main deductive loop */
}
/*
* Failing that, we have to do some _real_ work.
* Ideally what we do here is to try every single
* combination of the currently available sets, in an
* attempt to find a disjoint union (i.e. a set of
* squares with a known mine count between them) such
* that the remaining unknown squares _not_ contained
* in that union either contain no mines or are all
* mines.
*
* Actually enumerating all 2^n possibilities will get
* a bit slow for large n, so I artificially cap this
* recursion at n=10 to avoid too much pain.
*/
nsets = count234(ss->sets);
if (nsets <= lenof(setused)) {
/*
* Doing this with actual recursive function calls
* would get fiddly because a load of local
* variables from this function would have to be
* passed down through the recursion. So instead
* I'm going to use a virtual recursion within this
* function. The way this works is:
*
* - we have an array `setused', such that
* setused[n] is 0 or 1 depending on whether set
* n is currently in the union we are
* considering.
*
* - we have a value `cursor' which indicates how
* much of `setused' we have so far filled in.
* It's conceptually the recursion depth.
*
* We begin by setting `cursor' to zero. Then:
*
* - if cursor can advance, we advance it by one.
* We set the value in `setused' that it went
* past to 1 if that set is disjoint from
* anything else currently in `setused', or to 0
* otherwise.
*
* - If cursor cannot advance because it has
* reached the end of the setused list, then we
* have a maximal disjoint union. Check to see
* whether its mine count has any useful
* properties. If so, mark all the squares not
* in the union as known and terminate.
*
* - If cursor has reached the end of setused and
* the algorithm _hasn't_ terminated, back
* cursor up to the nearest 1, turn it into a 0
* and advance cursor just past it.
*
* - If we attempt to back up to the nearest 1 and
* there isn't one at all, then we have gone
* through all disjoint unions of sets in the
* list and none of them has been helpful, so we
* give up.
*/
struct set *sets[lenof(setused)];
for (i = 0; i < nsets; i++)
sets[i] = index234(ss->sets, i);
cursor = 0;
while (1) {
if (cursor < nsets) {
int ok = TRUE;
/* See if any existing set overlaps this one. */
for (i = 0; i < cursor; i++)
if (setused[i] &&
setmunge(sets[cursor]->x,
sets[cursor]->y,
sets[cursor]->mask,
sets[i]->x, sets[i]->y, sets[i]->mask,
FALSE)) {
ok = FALSE;
break;
}
if (ok) {
/*
* We're adding this set to our union,
* so adjust minesleft and squaresleft
* appropriately.
*/
minesleft -= sets[cursor]->mines;
squaresleft -= bitcount16(sets[cursor]->mask);
}
setused[cursor++] = ok;
} else {
#ifdef SOLVER_DIAGNOSTICS
printf("trying a set combination with %d %d\n",
squaresleft, minesleft);
#endif SOLVER_DIAGNOSTICS
/*
* We've reached the end. See if we've got
* anything interesting.
*/
if (squaresleft > 0 &&
(minesleft == 0 || minesleft == squaresleft)) {
/*
* We have! There is at least one
* square not contained within the set
* union we've just found, and we can
* deduce that either all such squares
* are mines or all are not (depending
* on whether minesleft==0). So now all
* we have to do is actually go through
* the grid, find those squares, and
* mark them.
*/
for (i = 0; i < w*h; i++)
if (grid[i] == -2) {
int outside = TRUE;
y = i / w;
x = i % w;
for (j = 0; j < nsets; j++)
if (setused[j] &&
setmunge(sets[j]->x, sets[j]->y,
sets[j]->mask, x, y, 1,
FALSE)) {
outside = FALSE;
break;
}
if (outside)
known_squares(w, h, std, grid,
open, ctx,
x, y, 1, minesleft != 0);
}
done_something = TRUE;
break; /* return to main deductive loop */
}
/*
* If we reach here, then this union hasn't
* done us any good, so move on to the
* next. Backtrack cursor to the nearest 1,
* change it to a 0 and continue.
*/
while (cursor-- >= 0 && !setused[cursor]);
if (cursor >= 0) {
assert(setused[cursor]);
/*
* We're removing this set from our
* union, so re-increment minesleft and
* squaresleft.
*/
minesleft += sets[cursor]->mines;
squaresleft += bitcount16(sets[cursor]->mask);
setused[cursor++] = 0;
} else {
/*
* We've backtracked all the way to the
* start without finding a single 1,
* which means that our virtual
* recursion is complete and nothing
* helped.
*/
break;
}
}
}
}
}
if (done_something)
continue;
#ifdef SOLVER_DIAGNOSTICS
/*
* Dump the current known state of the grid.
*/
printf("solver ran out of steam, ret=%d, grid:\n", nperturbs);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
int v = grid[y*w+x];
if (v == -1)
putchar('*');
else if (v == -2)
putchar('?');
else if (v == 0)
putchar('-');
else
putchar('0' + v);
}
putchar('\n');
}
{
struct set *s;
for (i = 0; (s = index234(ss->sets, i)) != NULL; i++)
printf("remaining set: %d,%d %03x %d\n", s->x, s->y, s->mask, s->mines);
}
#endif
/*
* Now we really are at our wits' end as far as solving
* this grid goes. Our only remaining option is to call
* a perturb function and ask it to modify the grid to
* make it easier.
*/
if (perturb) {
struct perturbations *ret;
struct set *s;
nperturbs++;
/*
* Choose a set at random from the current selection,
* and ask the perturb function to either fill or empty
* it.
*
* If we have no sets at all, we must give up.
*/
if (count234(ss->sets) == 0)
break;
s = index234(ss->sets, random_upto(rs, count234(ss->sets)));
#ifdef SOLVER_DIAGNOSTICS
printf("perturbing on set %d,%d %03x\n", s->x, s->y, s->mask);
#endif
ret = perturb(ctx, grid, s->x, s->y, s->mask);
if (ret) {
assert(ret->n > 0); /* otherwise should have been NULL */
/*
* A number of squares have been fiddled with, and
* the returned structure tells us which. Adjust
* the mine count in any set which overlaps one of
* those squares, and put them back on the to-do
* list.
*/
for (i = 0; i < ret->n; i++) {
#ifdef SOLVER_DIAGNOSTICS
printf("perturbation %s mine at %d,%d\n",
ret->changes[i].delta > 0 ? "added" : "removed",
ret->changes[i].x, ret->changes[i].y);
#endif
list = ss_overlap(ss,
ret->changes[i].x, ret->changes[i].y, 1);
for (j = 0; list[j]; j++) {
list[j]->mines += ret->changes[i].delta;
ss_add_todo(ss, list[j]);
}
sfree(list);
}
/*
* Now free the returned data.
*/
sfree(ret->changes);
sfree(ret);
#ifdef SOLVER_DIAGNOSTICS
/*
* Dump the current known state of the grid.
*/
printf("state after perturbation:\n", nperturbs);
for (y = 0; y < h; y++) {
for (x = 0; x < w; x++) {
int v = grid[y*w+x];
if (v == -1)
putchar('*');
else if (v == -2)
putchar('?');
else if (v == 0)
putchar('-');
else
putchar('0' + v);
}
putchar('\n');
}
{
struct set *s;
for (i = 0; (s = index234(ss->sets, i)) != NULL; i++)
printf("remaining set: %d,%d %03x %d\n", s->x, s->y, s->mask, s->mines);
}
#endif
/*
* And now we can go back round the deductive loop.
*/
continue;
}
}
/*
* If we get here, even that didn't work (either we didn't
* have a perturb function or it returned failure), so we
* give up entirely.
*/
break;
}
/*
* See if we've got any unknown squares left.
*/
for (y = 0; y < h; y++)
for (x = 0; x < w; x++)
if (grid[y*w+x] == -2) {
nperturbs = -1; /* failed to complete */
break;
}
/*
* Free the set list and square-todo list.
*/
{
struct set *s;
while ((s = delpos234(ss->sets, 0)) != NULL)
sfree(s);
freetree234(ss->sets);
sfree(ss);
sfree(std->next);
}
return nperturbs;
}
/* ----------------------------------------------------------------------
* Grid generator which uses the above solver.
*/
struct minectx {
char *grid;
int w, h;
int sx, sy;
random_state *rs;
};
static int mineopen(void *vctx, int x, int y)
{
struct minectx *ctx = (struct minectx *)vctx;
int i, j, n;
assert(x >= 0 && x < ctx->w && y >= 0 && y < ctx->h);
if (ctx->grid[y * ctx->w + x])
return -1; /* *bang* */
n = 0;
for (i = -1; i <= +1; i++) {
if (x + i < 0 || x + i >= ctx->w)
continue;
for (j = -1; j <= +1; j++) {
if (y + j < 0 || y + j >= ctx->h)
continue;
if (i == 0 && j == 0)
continue;
if (ctx->grid[(y+j) * ctx->w + (x+i)])
n++;
}
}
return n;
}
/* Structure used internally to mineperturb(). */
struct square {
int x, y, type, random;
};
static int squarecmp(const void *av, const void *bv)
{
const struct square *a = (const struct square *)av;
const struct square *b = (const struct square *)bv;
if (a->type < b->type)
return -1;
else if (a->type > b->type)
return +1;
else if (a->random < b->random)
return -1;
else if (a->random > b->random)
return +1;
else if (a->y < b->y)
return -1;
else if (a->y > b->y)
return +1;
else if (a->x < b->x)
return -1;
else if (a->x > b->x)
return +1;
return 0;
}
static struct perturbations *mineperturb(void *vctx, char *grid,
int setx, int sety, int mask)
{
struct minectx *ctx = (struct minectx *)vctx;
struct square *sqlist;
int x, y, dx, dy, i, n, nfull, nempty;
struct square *tofill[9], *toempty[9], **todo;
int ntofill, ntoempty, ntodo, dtodo, dset;
struct perturbations *ret;
/*
* Make a list of all the squares in the grid which we can
* possibly use. This list should be in preference order, which
* means
*
* - first, unknown squares on the boundary of known space
* - next, unknown squares beyond that boundary
* - as a very last resort, known squares, but not within one
* square of the starting position.
*
* Each of these sections needs to be shuffled independently.
* We do this by preparing list of all squares and then sorting
* it with a random secondary key.
*/
sqlist = snewn(ctx->w * ctx->h, struct square);
n = 0;
for (y = 0; y < ctx->h; y++)
for (x = 0; x < ctx->w; x++) {
/*
* If this square is too near the starting position,
* don't put it on the list at all.
*/
if (abs(y - ctx->sy) <= 1 && abs(x - ctx->sx) <= 1)
continue;
/*
* If this square is in the input set, also don't put
* it on the list!
*/
if (x >= setx && x < setx + 3 &&
y >= sety && y < sety + 3 &&
mask & (1 << ((y-sety)*3+(x-setx))))
continue;
sqlist[n].x = x;
sqlist[n].y = y;
if (grid[y*ctx->w+x] != -2) {
sqlist[n].type = 3; /* known square */
} else {
/*
* Unknown square. Examine everything around it and
* see if it borders on any known squares. If it
* does, it's class 1, otherwise it's 2.
*/
sqlist[n].type = 2;
for (dy = -1; dy <= +1; dy++)
for (dx = -1; dx <= +1; dx++)
if (x+dx >= 0 && x+dx < ctx->w &&
y+dy >= 0 && y+dy < ctx->h &&
grid[(y+dy)*ctx->w+(x+dx)] != -2) {
sqlist[n].type = 1;
break;
}
}
/*
* Finally, a random number to cause qsort to
* shuffle within each group.
*/
sqlist[n].random = random_bits(ctx->rs, 31);
n++;
}
qsort(sqlist, n, sizeof(struct square), squarecmp);
/*
* Now count up the number of full and empty squares in the set
* we've been provided.
*/
nfull = nempty = 0;
for (dy = 0; dy < 3; dy++)
for (dx = 0; dx < 3; dx++)
if (mask & (1 << (dy*3+dx))) {
assert(setx+dx <= ctx->w);
assert(sety+dy <= ctx->h);
if (ctx->grid[(sety+dy)*ctx->w+(setx+dx)])
nfull++;
else
nempty++;
}
/*
* Now go through our sorted list until we find either `nfull'
* empty squares, or `nempty' full squares; these will be
* swapped with the appropriate squares in the set to either
* fill or empty the set while keeping the same number of mines
* overall.
*/
ntofill = ntoempty = 0;
for (i = 0; i < n; i++) {
struct square *sq = &sqlist[i];
if (ctx->grid[sq->y * ctx->w + sq->x])
toempty[ntoempty++] = sq;
else
tofill[ntofill++] = sq;
if (ntofill == nfull || ntoempty == nempty)
break;
}
/*
* If this didn't work at all, I think we just give up.
*/
if (ntofill != nfull && ntoempty != nempty) {
sfree(sqlist);
return NULL;
}
/*
* Now we're pretty much there. We need to either
* (a) put a mine in each of the empty squares in the set, and
* take one out of each square in `toempty'
* (b) take a mine out of each of the full squares in the set,
* and put one in each square in `tofill'
* depending on which one we've found enough squares to do.
*
* So we start by constructing our list of changes to return to
* the solver, so that it can update its data structures
* efficiently rather than having to rescan the whole grid.
*/
ret = snew(struct perturbations);
if (ntofill == nfull) {
todo = tofill;
ntodo = ntofill;
dtodo = +1;
dset = -1;
} else {
todo = toempty;
ntodo = ntoempty;
dtodo = -1;
dset = +1;
}
ret->n = 2 * ntodo;
ret->changes = snewn(ret->n, struct perturbation);
for (i = 0; i < ntodo; i++) {
ret->changes[i].x = todo[i]->x;
ret->changes[i].y = todo[i]->y;
ret->changes[i].delta = dtodo;
}
/* now i == ntodo */
for (dy = 0; dy < 3; dy++)
for (dx = 0; dx < 3; dx++)
if (mask & (1 << (dy*3+dx))) {
int currval = (ctx->grid[(sety+dy)*ctx->w+(setx+dx)] ? +1 : -1);
if (dset == -currval) {
ret->changes[i].x = setx + dx;
ret->changes[i].y = sety + dy;
ret->changes[i].delta = dset;
i++;
}
}
assert(i == ret->n);
sfree(sqlist);
/*
* Having set up the precise list of changes we're going to
* make, we now simply make them and return.
*/
for (i = 0; i < ret->n; i++) {
int delta;
x = ret->changes[i].x;
y = ret->changes[i].y;
delta = ret->changes[i].delta;
/*
* Check we're not trying to add an existing mine or remove
* an absent one.
*/
assert((delta < 0) ^ (ctx->grid[y*ctx->w+x] == 0));
/*
* Actually make the change.
*/
ctx->grid[y*ctx->w+x] = (delta > 0);
/*
* Update any numbers already present in the grid.
*/
for (dy = -1; dy <= +1; dy++)
for (dx = -1; dx <= +1; dx++)
if (x+dx >= 0 && x+dx < ctx->w &&
y+dy >= 0 && y+dy < ctx->h &&
grid[(y+dy)*ctx->w+(x+dx)] != -2) {
if (dx == 0 && dy == 0) {
/*
* The square itself is marked as known in
* the grid. Mark it as a mine if it's a
* mine, or else work out its number.
*/
if (delta > 0) {
grid[y*ctx->w+x] = -1;
} else {
int dx2, dy2, minecount = 0;
for (dy2 = -1; dy2 <= +1; dy2++)
for (dx2 = -1; dx2 <= +1; dx2++)
if (x+dx2 >= 0 && x+dx2 < ctx->w &&
y+dy2 >= 0 && y+dy2 < ctx->h &&
ctx->grid[(y+dy2)*ctx->w+(x+dx2)])
minecount++;
grid[y*ctx->w+x] = minecount;
}
} else {
if (grid[(y+dy)*ctx->w+(x+dx)] >= 0)
grid[(y+dy)*ctx->w+(x+dx)] += delta;
}
}
}
#ifdef GENERATION_DIAGNOSTICS
{
int yy, xx;
printf("grid after perturbing:\n");
for (yy = 0; yy < ctx->h; yy++) {
for (xx = 0; xx < ctx->w; xx++) {
int v = ctx->grid[yy*ctx->w+xx];
if (yy == ctx->sy && xx == ctx->sx) {
assert(!v);
putchar('S');
} else if (v) {
putchar('*');
} else {
putchar('-');
}
}
putchar('\n');
}
printf("\n");
}
#endif
return ret;
}
static char *minegen(int w, int h, int n, int x, int y, int unique,
random_state *rs)
{
char *ret = snewn(w*h, char);
int success;
do {
success = FALSE;
memset(ret, 0, w*h);
/*
* Start by placing n mines, none of which is at x,y or within
* one square of it.
*/
{
int *tmp = snewn(w*h, int);
int i, j, k, nn;
/*
* Write down the list of possible mine locations.
*/
k = 0;
for (i = 0; i < h; i++)
for (j = 0; j < w; j++)
if (abs(i - y) > 1 || abs(j - x) > 1)
tmp[k++] = i*w+j;
/*
* Now pick n off the list at random.
*/
nn = n;
while (nn-- > 0) {
i = random_upto(rs, k);
ret[tmp[i]] = 1;
tmp[i] = tmp[--k];
}
sfree(tmp);
}
#ifdef GENERATION_DIAGNOSTICS
{
int yy, xx;
printf("grid after initial generation:\n");
for (yy = 0; yy < h; yy++) {
for (xx = 0; xx < w; xx++) {
int v = ret[yy*w+xx];
if (yy == y && xx == x) {
assert(!v);
putchar('S');
} else if (v) {
putchar('*');
} else {
putchar('-');
}
}
putchar('\n');
}
printf("\n");
}
#endif
/*
* Now set up a results grid to run the solver in, and a
* context for the solver to open squares. Then run the solver
* repeatedly; if the number of perturb steps ever goes up or
* it ever returns -1, give up completely.
*
* We bypass this bit if we're not after a unique grid.
*/
if (unique) {
char *solvegrid = snewn(w*h, char);
struct minectx actx, *ctx = &actx;
int solveret, prevret = -2;
ctx->grid = ret;
ctx->w = w;
ctx->h = h;
ctx->sx = x;
ctx->sy = y;
ctx->rs = rs;
while (1) {
memset(solvegrid, -2, w*h);
solvegrid[y*w+x] = mineopen(ctx, x, y);
assert(solvegrid[y*w+x] == 0); /* by deliberate arrangement */
solveret =
minesolve(w, h, n, solvegrid, mineopen, mineperturb, ctx, rs);
if (solveret < 0 || (prevret >= 0 && solveret >= prevret)) {
success = FALSE;
break;
} else if (solveret == 0) {
success = TRUE;
break;
}
}
sfree(solvegrid);
} else {
success = TRUE;
}
} while (!success);
return ret;
}
/*
* The Mines game descriptions contain the location of every mine,
* and can therefore be used to cheat.
*
* It would be pointless to attempt to _prevent_ this form of
* cheating by encrypting the description, since Mines is
* open-source so anyone can find out the encryption key. However,
* I think it is worth doing a bit of gentle obfuscation to prevent
* _accidental_ spoilers: if you happened to note that the game ID
* starts with an F, for example, you might be unable to put the
* knowledge of those mines out of your mind while playing. So,
* just as discussions of film endings are rot13ed to avoid
* spoiling it for people who don't want to be told, we apply a
* keyless, reversible, but visually completely obfuscatory masking
* function to the mine bitmap.
*/
static void obfuscate_bitmap(unsigned char *bmp, int bits, int decode)
{
int bytes, firsthalf, secondhalf;
struct step {
unsigned char *seedstart;
int seedlen;
unsigned char *targetstart;
int targetlen;
} steps[2];
int i, j;
/*
* My obfuscation algorithm is similar in concept to the OAEP
* encoding used in some forms of RSA. Here's a specification
* of it:
*
* + We have a `masking function' which constructs a stream of
* pseudorandom bytes from a seed of some number of input
* bytes.
*
* + We pad out our input bit stream to a whole number of
* bytes by adding up to 7 zero bits on the end. (In fact
* the bitmap passed as input to this function will already
* have had this done in practice.)
*
* + We divide the _byte_ stream exactly in half, rounding the
* half-way position _down_. So an 81-bit input string, for
* example, rounds up to 88 bits or 11 bytes, and then
* dividing by two gives 5 bytes in the first half and 6 in
* the second half.
*
* + We generate a mask from the second half of the bytes, and
* XOR it over the first half.
*
* + We generate a mask from the (encoded) first half of the
* bytes, and XOR it over the second half. Any null bits at
* the end which were added as padding are cleared back to
* zero even if this operation would have made them nonzero.
*
* To de-obfuscate, the steps are precisely the same except
* that the final two are reversed.
*
* Finally, our masking function. Given an input seed string of
* bytes, the output mask consists of concatenating the SHA-1
* hashes of the seed string and successive decimal integers,
* starting from 0.
*/
bytes = (bits + 7) / 8;
firsthalf = bytes / 2;
secondhalf = bytes - firsthalf;
steps[decode ? 1 : 0].seedstart = bmp + firsthalf;
steps[decode ? 1 : 0].seedlen = secondhalf;
steps[decode ? 1 : 0].targetstart = bmp;
steps[decode ? 1 : 0].targetlen = firsthalf;
steps[decode ? 0 : 1].seedstart = bmp;
steps[decode ? 0 : 1].seedlen = firsthalf;
steps[decode ? 0 : 1].targetstart = bmp + firsthalf;
steps[decode ? 0 : 1].targetlen = secondhalf;
for (i = 0; i < 2; i++) {
SHA_State base, final;
unsigned char digest[20];
char numberbuf[80];
int digestpos = 20, counter = 0;
SHA_Init(&base);
SHA_Bytes(&base, steps[i].seedstart, steps[i].seedlen);
for (j = 0; j < steps[i].targetlen; j++) {
if (digestpos >= 20) {
sprintf(numberbuf, "%d", counter++);
final = base;
SHA_Bytes(&final, numberbuf, strlen(numberbuf));
SHA_Final(&final, digest);
digestpos = 0;
}
steps[i].targetstart[j] ^= digest[digestpos]++;
}
/*
* Mask off the pad bits in the final byte after both steps.
*/
if (bits % 8)
bmp[bits / 8] &= 0xFF & (0xFF00 >> (bits % 8));
}
}
static char *new_game_desc(game_params *params, random_state *rs,
game_aux_info **aux)
{
char *grid, *ret, *p;
unsigned char *bmp;
int x, y, i, area;
/*
* FIXME: allow user to specify initial open square.
*/
x = random_upto(rs, params->w);
y = random_upto(rs, params->h);
grid = minegen(params->w, params->h, params->n, x, y, params->unique, rs);
/*
* Set up the mine bitmap and obfuscate it.
*/
area = params->w * params->h;
bmp = snewn((area + 7) / 8, unsigned char);
memset(bmp, 0, (area + 7) / 8);
for (i = 0; i < area; i++) {
if (grid[i])
bmp[i / 8] |= 0x80 >> (i % 8);
}
obfuscate_bitmap(bmp, area, FALSE);
/*
* Now encode the resulting bitmap in hex. We can work to
* nibble rather than byte granularity, since the obfuscation
* function guarantees to return a bit string of the same
* length as its input.
*/
ret = snewn((area+3)/4 + 100, char);
p = ret + sprintf(ret, "%d,%d,m", x, y); /* 'm' == masked */
for (i = 0; i < (area+3)/4; i++) {
int v = bmp[i/2];
if (i % 2 == 0)
v >>= 4;
*p++ = "0123456789abcdef"[v & 0xF];
}
*p = '\0';
sfree(bmp);
return ret;
}
static void game_free_aux_info(game_aux_info *aux)
{
assert(!"Shouldn't happen");
}
static char *validate_desc(game_params *params, char *desc)
{
int wh = params->w * params->h;
int x, y;
if (!*desc || !isdigit((unsigned char)*desc))
return "No initial x-coordinate in game description";
x = atoi(desc);
if (x < 0 || x >= params->w)
return "Initial x-coordinate was out of range";
while (*desc && isdigit((unsigned char)*desc))
desc++; /* skip over x coordinate */
if (*desc != ',')
return "No ',' after initial x-coordinate in game description";
desc++; /* eat comma */
if (!*desc || !isdigit((unsigned char)*desc))
return "No initial y-coordinate in game description";
y = atoi(desc);
if (y < 0 || y >= params->h)
return "Initial y-coordinate was out of range";
while (*desc && isdigit((unsigned char)*desc))
desc++; /* skip over y coordinate */
if (*desc != ',')
return "No ',' after initial y-coordinate in game description";
desc++; /* eat comma */
/* eat `m', meaning `masked', if present */
if (*desc == 'm')
desc++;
/* now just check length of remainder */
if (strlen(desc) != (wh+3)/4)
return "Game description is wrong length";
return NULL;
}
static int open_square(game_state *state, int x, int y)
{
int w = state->w, h = state->h;
int xx, yy, nmines, ncovered;
if (state->mines[y*w+x]) {
/*
* The player has landed on a mine. Bad luck. Expose all
* the mines.
*/
state->dead = TRUE;
for (yy = 0; yy < h; yy++)
for (xx = 0; xx < w; xx++) {
if (state->mines[yy*w+xx] &&
(state->grid[yy*w+xx] == -2 ||
state->grid[yy*w+xx] == -3)) {
state->grid[yy*w+xx] = 64;
}
if (!state->mines[yy*w+xx] &&
state->grid[yy*w+xx] == -1) {
state->grid[yy*w+xx] = 66;
}
}
state->grid[y*w+x] = 65;
return -1;
}
/*
* Otherwise, the player has opened a safe square. Mark it to-do.
*/
state->grid[y*w+x] = -10; /* `todo' value internal to this func */
/*
* Now go through the grid finding all `todo' values and
* opening them. Every time one of them turns out to have no
* neighbouring mines, we add all its unopened neighbours to
* the list as well.
*
* FIXME: We really ought to be able to do this better than
* using repeated N^2 scans of the grid.
*/
while (1) {
int done_something = FALSE;
for (yy = 0; yy < h; yy++)
for (xx = 0; xx < w; xx++)
if (state->grid[yy*w+xx] == -10) {
int dx, dy, v;
assert(!state->mines[yy*w+xx]);
v = 0;
for (dx = -1; dx <= +1; dx++)
for (dy = -1; dy <= +1; dy++)
if (xx+dx >= 0 && xx+dx < state->w &&
yy+dy >= 0 && yy+dy < state->h &&
state->mines[(yy+dy)*w+(xx+dx)])
v++;
state->grid[yy*w+xx] = v;
if (v == 0) {
for (dx = -1; dx <= +1; dx++)
for (dy = -1; dy <= +1; dy++)
if (xx+dx >= 0 && xx+dx < state->w &&
yy+dy >= 0 && yy+dy < state->h &&
state->grid[(yy+dy)*w+(xx+dx)] == -2)
state->grid[(yy+dy)*w+(xx+dx)] = -10;
}
done_something = TRUE;
}
if (!done_something)
break;
}
/*
* Finally, scan the grid and see if exactly as many squares
* are still covered as there are mines. If so, set the `won'
* flag and fill in mine markers on all covered squares.
*/
nmines = ncovered = 0;
for (yy = 0; yy < h; yy++)
for (xx = 0; xx < w; xx++) {
if (state->grid[yy*w+xx] < 0)
ncovered++;
if (state->mines[yy*w+xx])
nmines++;
}
assert(ncovered >= nmines);
if (ncovered == nmines) {
for (yy = 0; yy < h; yy++)
for (xx = 0; xx < w; xx++) {
if (state->grid[yy*w+xx] < 0)
state->grid[yy*w+xx] = -1;
}
state->won = TRUE;
}
return 0;
}
static game_state *new_game(game_params *params, char *desc)
{
game_state *state = snew(game_state);
int i, wh, x, y, ret, masked;
unsigned char *bmp;
state->w = params->w;
state->h = params->h;
state->n = params->n;
state->dead = state->won = FALSE;
wh = state->w * state->h;
state->mines = snewn(wh, char);
x = atoi(desc);
while (*desc && isdigit((unsigned char)*desc))
desc++; /* skip over x coordinate */
if (*desc) desc++; /* eat comma */
y = atoi(desc);
while (*desc && isdigit((unsigned char)*desc))
desc++; /* skip over y coordinate */
if (*desc) desc++; /* eat comma */
if (*desc == 'm') {
masked = TRUE;
desc++;
} else {
/*
* We permit game IDs to be entered by hand without the
* masking transformation.
*/
masked = FALSE;
}
bmp = snewn((wh + 7) / 8, unsigned char);
memset(bmp, 0, (wh + 7) / 8);
for (i = 0; i < (wh+3)/4; i++) {
int c = desc[i];
int v;
assert(c != 0); /* validate_desc should have caught */
if (c >= '0' && c <= '9')
v = c - '0';
else if (c >= 'a' && c <= 'f')
v = c - 'a' + 10;
else if (c >= 'A' && c <= 'F')
v = c - 'A' + 10;
else
v = 0;
bmp[i / 2] |= v << (4 * (1 - (i % 2)));
}
if (masked)
obfuscate_bitmap(bmp, wh, TRUE);
memset(state->mines, 0, wh);
for (i = 0; i < wh; i++) {
if (bmp[i / 8] & (0x80 >> (i % 8)))
state->mines[i] = 1;
}
state->grid = snewn(wh, char);
memset(state->grid, -2, wh);
ret = open_square(state, x, y);
/*
* FIXME: This shouldn't be an assert. Perhaps we actually
* ought to check it in validate_params! Alternatively, we can
* remove the assert completely and actually permit a game
* description to start you off dead.
*/
assert(ret != -1);
return state;
}
static game_state *dup_game(game_state *state)
{
game_state *ret = snew(game_state);
ret->w = state->w;
ret->h = state->h;
ret->n = state->n;
ret->dead = state->dead;
ret->won = state->won;
ret->mines = snewn(ret->w * ret->h, char);
memcpy(ret->mines, state->mines, ret->w * ret->h);
ret->grid = snewn(ret->w * ret->h, char);
memcpy(ret->grid, state->grid, ret->w * ret->h);
return ret;
}
static void free_game(game_state *state)
{
sfree(state->mines);
sfree(state->grid);
sfree(state);
}
static game_state *solve_game(game_state *state, game_aux_info *aux,
char **error)
{
return NULL;
}
static char *game_text_format(game_state *state)
{
return NULL;
}
struct game_ui {
int hx, hy, hradius; /* for mouse-down highlights */
int flash_is_death;
};
static game_ui *new_ui(game_state *state)
{
game_ui *ui = snew(game_ui);
ui->hx = ui->hy = -1;
ui->hradius = 0;
ui->flash_is_death = FALSE; /* *shrug* */
return ui;
}
static void free_ui(game_ui *ui)
{
sfree(ui);
}
static game_state *make_move(game_state *from, game_ui *ui, int x, int y,
int button)
{
game_state *ret;
int cx, cy;
if (from->dead || from->won)
return NULL; /* no further moves permitted */
if (!IS_MOUSE_DOWN(button) && !IS_MOUSE_DRAG(button) &&
!IS_MOUSE_RELEASE(button))
return NULL;
cx = FROMCOORD(x);
cy = FROMCOORD(y);
if (cx < 0 || cx >= from->w || cy < 0 || cy > from->h)
return NULL;
if (button == LEFT_BUTTON || button == LEFT_DRAG) {
/*
* Mouse-downs and mouse-drags just cause highlighting
* updates.
*/
ui->hx = cx;
ui->hy = cy;
ui->hradius = (from->grid[cy*from->w+cx] >= 0 ? 1 : 0);
return from;
}
if (button == RIGHT_BUTTON) {
/*
* Right-clicking only works on a covered square, and it
* toggles between -1 (marked as mine) and -2 (not marked
* as mine).
*
* FIXME: question marks.
*/
if (from->grid[cy * from->w + cx] != -2 &&
from->grid[cy * from->w + cx] != -1)
return NULL;
ret = dup_game(from);
ret->grid[cy * from->w + cx] ^= (-2 ^ -1);
return ret;
}
if (button == LEFT_RELEASE) {
ui->hx = ui->hy = -1;
ui->hradius = 0;
/*
* At this stage we must never return NULL: we have adjusted
* the ui, so at worst we return `from'.
*/
/*
* Left-clicking on a covered square opens a tile. Not
* permitted if the tile is marked as a mine, for safety.
* (Unmark it and _then_ open it.)
*/
if (from->grid[cy * from->w + cx] == -2 ||
from->grid[cy * from->w + cx] == -3) {
ret = dup_game(from);
open_square(ret, cx, cy);
return ret;
}
/*
* Left-clicking on an uncovered tile: first we check to see if
* the number of mine markers surrounding the tile is equal to
* its mine count, and if so then we open all other surrounding
* squares.
*/
if (from->grid[cy * from->w + cx] > 0) {
int dy, dx, n;
/* Count mine markers. */
n = 0;
for (dy = -1; dy <= +1; dy++)
for (dx = -1; dx <= +1; dx++)
if (cx+dx >= 0 && cx+dx < from->w &&
cy+dy >= 0 && cy+dy < from->h) {
if (from->grid[(cy+dy)*from->w+(cx+dx)] == -1)
n++;
}
if (n == from->grid[cy * from->w + cx]) {
ret = dup_game(from);
for (dy = -1; dy <= +1; dy++)
for (dx = -1; dx <= +1; dx++)
if (cx+dx >= 0 && cx+dx < ret->w &&
cy+dy >= 0 && cy+dy < ret->h &&
(ret->grid[(cy+dy)*ret->w+(cx+dx)] == -2 ||
ret->grid[(cy+dy)*ret->w+(cx+dx)] == -3))
open_square(ret, cx+dx, cy+dy);
return ret;
}
}
return from;
}
return NULL;
}
/* ----------------------------------------------------------------------
* Drawing routines.
*/
struct game_drawstate {
int w, h, started;
char *grid;
/*
* Items in this `grid' array have all the same values as in
* the game_state grid, and in addition:
*
* - -10 means the tile was drawn `specially' as a result of a
* flash, so it will always need redrawing.
*
* - -22 and -23 mean the tile is highlighted for a possible
* click.
*/
};
static void game_size(game_params *params, int *x, int *y)
{
*x = BORDER * 2 + TILE_SIZE * params->w;
*y = BORDER * 2 + TILE_SIZE * params->h;
}
static float *game_colours(frontend *fe, game_state *state, int *ncolours)
{
float *ret = snewn(3 * NCOLOURS, float);
frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
ret[COL_1 * 3 + 0] = 0.0F;
ret[COL_1 * 3 + 1] = 0.0F;
ret[COL_1 * 3 + 2] = 1.0F;
ret[COL_2 * 3 + 0] = 0.0F;
ret[COL_2 * 3 + 1] = 0.5F;
ret[COL_2 * 3 + 2] = 0.0F;
ret[COL_3 * 3 + 0] = 1.0F;
ret[COL_3 * 3 + 1] = 0.0F;
ret[COL_3 * 3 + 2] = 0.0F;
ret[COL_4 * 3 + 0] = 0.0F;
ret[COL_4 * 3 + 1] = 0.0F;
ret[COL_4 * 3 + 2] = 0.5F;
ret[COL_5 * 3 + 0] = 0.5F;
ret[COL_5 * 3 + 1] = 0.0F;
ret[COL_5 * 3 + 2] = 0.0F;
ret[COL_6 * 3 + 0] = 0.0F;
ret[COL_6 * 3 + 1] = 0.5F;
ret[COL_6 * 3 + 2] = 0.5F;
ret[COL_7 * 3 + 0] = 0.0F;
ret[COL_7 * 3 + 1] = 0.0F;
ret[COL_7 * 3 + 2] = 0.0F;
ret[COL_8 * 3 + 0] = 0.5F;
ret[COL_8 * 3 + 1] = 0.5F;
ret[COL_8 * 3 + 2] = 0.5F;
ret[COL_MINE * 3 + 0] = 0.0F;
ret[COL_MINE * 3 + 1] = 0.0F;
ret[COL_MINE * 3 + 2] = 0.0F;
ret[COL_BANG * 3 + 0] = 1.0F;
ret[COL_BANG * 3 + 1] = 0.0F;
ret[COL_BANG * 3 + 2] = 0.0F;
ret[COL_CROSS * 3 + 0] = 1.0F;
ret[COL_CROSS * 3 + 1] = 0.0F;
ret[COL_CROSS * 3 + 2] = 0.0F;
ret[COL_FLAG * 3 + 0] = 1.0F;
ret[COL_FLAG * 3 + 1] = 0.0F;
ret[COL_FLAG * 3 + 2] = 0.0F;
ret[COL_FLAGBASE * 3 + 0] = 0.0F;
ret[COL_FLAGBASE * 3 + 1] = 0.0F;
ret[COL_FLAGBASE * 3 + 2] = 0.0F;
ret[COL_QUERY * 3 + 0] = 0.0F;
ret[COL_QUERY * 3 + 1] = 0.0F;
ret[COL_QUERY * 3 + 2] = 0.0F;
ret[COL_HIGHLIGHT * 3 + 0] = 1.0F;
ret[COL_HIGHLIGHT * 3 + 1] = 1.0F;
ret[COL_HIGHLIGHT * 3 + 2] = 1.0F;
ret[COL_LOWLIGHT * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 2.0 / 3.0;
ret[COL_LOWLIGHT * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 2.0 / 3.0;
ret[COL_LOWLIGHT * 3 + 2] = ret[COL_BACKGROUND * 3 + 2] * 2.0 / 3.0;
*ncolours = NCOLOURS;
return ret;
}
static game_drawstate *game_new_drawstate(game_state *state)
{
struct game_drawstate *ds = snew(struct game_drawstate);
ds->w = state->w;
ds->h = state->h;
ds->started = FALSE;
ds->grid = snewn(ds->w * ds->h, char);
memset(ds->grid, -99, ds->w * ds->h);
return ds;
}
static void game_free_drawstate(game_drawstate *ds)
{
sfree(ds->grid);
sfree(ds);
}
static void draw_tile(frontend *fe, int x, int y, int v, int bg)
{
if (v < 0) {
int coords[12];
int hl = 0;
if (v == -22 || v == -23) {
v += 20;
/*
* Omit the highlights in this case.
*/
draw_rect(fe, x, y, TILE_SIZE, TILE_SIZE, bg);
draw_line(fe, x, y, x + TILE_SIZE - 1, y, COL_LOWLIGHT);
draw_line(fe, x, y, x, y + TILE_SIZE - 1, COL_LOWLIGHT);
} else {
/*
* Draw highlights to indicate the square is covered.
*/
coords[0] = x + TILE_SIZE - 1;
coords[1] = y + TILE_SIZE - 1;
coords[2] = x + TILE_SIZE - 1;
coords[3] = y;
coords[4] = x;
coords[5] = y + TILE_SIZE - 1;
draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT ^ hl);
draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT ^ hl);
coords[0] = x;
coords[1] = y;
draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT ^ hl);
draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT ^ hl);
draw_rect(fe, x + HIGHLIGHT_WIDTH, y + HIGHLIGHT_WIDTH,
TILE_SIZE - 2*HIGHLIGHT_WIDTH, TILE_SIZE - 2*HIGHLIGHT_WIDTH,
bg);
}
if (v == -1) {
/*
* Draw a flag.
*/
#define SETCOORD(n, dx, dy) do { \
coords[(n)*2+0] = x + TILE_SIZE * (dx); \
coords[(n)*2+1] = y + TILE_SIZE * (dy); \
} while (0)
SETCOORD(0, 0.6, 0.35);
SETCOORD(1, 0.6, 0.7);
SETCOORD(2, 0.8, 0.8);
SETCOORD(3, 0.25, 0.8);
SETCOORD(4, 0.55, 0.7);
SETCOORD(5, 0.55, 0.35);
draw_polygon(fe, coords, 6, TRUE, COL_FLAGBASE);
draw_polygon(fe, coords, 6, FALSE, COL_FLAGBASE);
SETCOORD(0, 0.6, 0.2);
SETCOORD(1, 0.6, 0.5);
SETCOORD(2, 0.2, 0.35);
draw_polygon(fe, coords, 3, TRUE, COL_FLAG);
draw_polygon(fe, coords, 3, FALSE, COL_FLAG);
#undef SETCOORD
} else if (v == -3) {
/*
* Draw a question mark.
*/
draw_text(fe, x + TILE_SIZE / 2, y + TILE_SIZE / 2,
FONT_VARIABLE, TILE_SIZE * 6 / 8,
ALIGN_VCENTRE | ALIGN_HCENTRE,
COL_QUERY, "?");
}
} else {
/*
* Clear the square to the background colour, and draw thin
* grid lines along the top and left.
*
* Exception is that for value 65 (mine we've just trodden
* on), we clear the square to COL_BANG.
*/
draw_rect(fe, x, y, TILE_SIZE, TILE_SIZE,
(v == 65 ? COL_BANG : bg));
draw_line(fe, x, y, x + TILE_SIZE - 1, y, COL_LOWLIGHT);
draw_line(fe, x, y, x, y + TILE_SIZE - 1, COL_LOWLIGHT);
if (v > 0 && v <= 8) {
/*
* Mark a number.
*/
char str[2];
str[0] = v + '0';
str[1] = '\0';
draw_text(fe, x + TILE_SIZE / 2, y + TILE_SIZE / 2,
FONT_VARIABLE, TILE_SIZE * 7 / 8,
ALIGN_VCENTRE | ALIGN_HCENTRE,
(COL_1 - 1) + v, str);
} else if (v >= 64) {
/*
* Mark a mine.
*
* FIXME: this could be done better!
*/
#if 0
draw_text(fe, x + TILE_SIZE / 2, y + TILE_SIZE / 2,
FONT_VARIABLE, TILE_SIZE * 7 / 8,
ALIGN_VCENTRE | ALIGN_HCENTRE,
COL_MINE, "*");
#else
{
int cx = x + TILE_SIZE / 2;
int cy = y + TILE_SIZE / 2;
int r = TILE_SIZE / 2 - 3;
int coords[4*5*2];
int xdx = 1, xdy = 0, ydx = 0, ydy = 1;
int tdx, tdy, i;
for (i = 0; i < 4*5*2; i += 5*2) {
coords[i+2*0+0] = cx - r/6*xdx + r*4/5*ydx;
coords[i+2*0+1] = cy - r/6*xdy + r*4/5*ydy;
coords[i+2*1+0] = cx - r/6*xdx + r*ydx;
coords[i+2*1+1] = cy - r/6*xdy + r*ydy;
coords[i+2*2+0] = cx + r/6*xdx + r*ydx;
coords[i+2*2+1] = cy + r/6*xdy + r*ydy;
coords[i+2*3+0] = cx + r/6*xdx + r*4/5*ydx;
coords[i+2*3+1] = cy + r/6*xdy + r*4/5*ydy;
coords[i+2*4+0] = cx + r*3/5*xdx + r*3/5*ydx;
coords[i+2*4+1] = cy + r*3/5*xdy + r*3/5*ydy;
tdx = ydx;
tdy = ydy;
ydx = xdx;
ydy = xdy;
xdx = -tdx;
xdy = -tdy;
}
draw_polygon(fe, coords, 5*4, TRUE, COL_MINE);
draw_polygon(fe, coords, 5*4, FALSE, COL_MINE);
draw_rect(fe, cx-r/3, cy-r/3, r/3, r/4, COL_HIGHLIGHT);
}
#endif
if (v == 66) {
/*
* Cross through the mine.
*/
int dx;
for (dx = -1; dx <= +1; dx++) {
draw_line(fe, x + 3 + dx, y + 2,
x + TILE_SIZE - 3 + dx,
y + TILE_SIZE - 2, COL_CROSS);
draw_line(fe, x + TILE_SIZE - 3 + dx, y + 2,
x + 3 + dx, y + TILE_SIZE - 2,
COL_CROSS);
}
}
}
}
draw_update(fe, x, y, TILE_SIZE, TILE_SIZE);
}
static void game_redraw(frontend *fe, game_drawstate *ds, game_state *oldstate,
game_state *state, int dir, game_ui *ui,
float animtime, float flashtime)
{
int x, y;
int mines, markers, bg;
if (flashtime) {
int frame = (flashtime / FLASH_FRAME);
if (frame % 2)
bg = (ui->flash_is_death ? COL_BACKGROUND : COL_LOWLIGHT);
else
bg = (ui->flash_is_death ? COL_BANG : COL_HIGHLIGHT);
} else
bg = COL_BACKGROUND;
if (!ds->started) {
int coords[6];
draw_rect(fe, 0, 0,
TILE_SIZE * state->w + 2 * BORDER,
TILE_SIZE * state->h + 2 * BORDER, COL_BACKGROUND);
draw_update(fe, 0, 0,
TILE_SIZE * state->w + 2 * BORDER,
TILE_SIZE * state->h + 2 * BORDER);
/*
* Recessed area containing the whole puzzle.
*/
coords[0] = COORD(state->w) + OUTER_HIGHLIGHT_WIDTH - 1;
coords[1] = COORD(state->h) + OUTER_HIGHLIGHT_WIDTH - 1;
coords[2] = COORD(state->w) + OUTER_HIGHLIGHT_WIDTH - 1;
coords[3] = COORD(0) - OUTER_HIGHLIGHT_WIDTH;
coords[4] = COORD(0) - OUTER_HIGHLIGHT_WIDTH;
coords[5] = COORD(state->h) + OUTER_HIGHLIGHT_WIDTH - 1;
draw_polygon(fe, coords, 3, TRUE, COL_HIGHLIGHT);
draw_polygon(fe, coords, 3, FALSE, COL_HIGHLIGHT);
coords[1] = COORD(0) - OUTER_HIGHLIGHT_WIDTH;
coords[0] = COORD(0) - OUTER_HIGHLIGHT_WIDTH;
draw_polygon(fe, coords, 3, TRUE, COL_LOWLIGHT);
draw_polygon(fe, coords, 3, FALSE, COL_LOWLIGHT);
ds->started = TRUE;
}
/*
* Now draw the tiles. Also in this loop, count up the number
* of mines and mine markers.
*/
mines = markers = 0;
for (y = 0; y < ds->h; y++)
for (x = 0; x < ds->w; x++) {
int v = state->grid[y*ds->w+x];
if (v == -1)
markers++;
if (state->mines[y*ds->w+x])
mines++;
if ((v == -2 || v == -3) &&
(abs(x-ui->hx) <= ui->hradius && abs(y-ui->hy) <= ui->hradius))
v -= 20;
if (ds->grid[y*ds->w+x] != v || bg != COL_BACKGROUND) {
draw_tile(fe, COORD(x), COORD(y), v, bg);
ds->grid[y*ds->w+x] = (bg == COL_BACKGROUND ? v : -10);
}
}
/*
* Update the status bar.
*/
{
char statusbar[512];
if (state->dead) {
sprintf(statusbar, "GAME OVER!");
} else if (state->won) {
sprintf(statusbar, "COMPLETED!");
} else {
sprintf(statusbar, "Mines marked: %d / %d", markers, mines);
}
status_bar(fe, statusbar);
}
}
static float game_anim_length(game_state *oldstate, game_state *newstate,
int dir, game_ui *ui)
{
return 0.0F;
}
static float game_flash_length(game_state *oldstate, game_state *newstate,
int dir, game_ui *ui)
{
if (dir > 0 && !oldstate->dead && !oldstate->won) {
if (newstate->dead) {
ui->flash_is_death = TRUE;
return 3 * FLASH_FRAME;
}
if (newstate->won) {
ui->flash_is_death = FALSE;
return 2 * FLASH_FRAME;
}
}
return 0.0F;
}
static int game_wants_statusbar(void)
{
return TRUE;
}
#ifdef COMBINED
#define thegame mines
#endif
const struct game thegame = {
"Mines", "games.mines",
default_params,
game_fetch_preset,
decode_params,
encode_params,
free_params,
dup_params,
TRUE, game_configure, custom_params,
validate_params,
new_game_desc,
game_free_aux_info,
validate_desc,
new_game,
dup_game,
free_game,
FALSE, solve_game,
FALSE, game_text_format,
new_ui,
free_ui,
make_move,
game_size,
game_colours,
game_new_drawstate,
game_free_drawstate,
game_redraw,
game_anim_length,
game_flash_length,
game_wants_statusbar,
};
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