1 /* -*- tab-width: 8; indent-tabs-mode: t -*-
2  * filling.c: An implementation of the Nikoli game fillomino.
3  * Copyright (C) 2007 Jonas Kölker.  See LICENSE for the license.
4  */
5 
6 /* TODO:
7  *
8  *  - use a typedef instead of int for numbers on the board
9  *     + replace int with something else (signed short?)
10  *        - the type should be signed (for -board[i] and -SENTINEL)
11  *        - the type should be somewhat big: board[i] = i
12  *        - Using shorts gives us 181x181 puzzles as upper bound.
13  *
14  *  - in board generation, after having merged regions such that no
15  *    more merges are necessary, try splitting (big) regions.
16  *     + it seems that smaller regions make for better puzzles; see
17  *       for instance the 7x7 puzzle in this file (grep for 7x7:).
18  *
19  *  - symmetric hints (solo-style)
20  *     + right now that means including _many_ hints, and the puzzles
21  *       won't look any nicer.  Not worth it (at the moment).
22  *
23  *  - make the solver do recursion/backtracking.
24  *     + This is for user-submitted puzzles, not for puzzle
25  *       generation (on the other hand, never say never).
26  *
27  *  - prove that only w=h=2 needs a special case
28  *
29  *  - solo-like pencil marks?
30  *
31  *  - a user says that the difficulty is unevenly distributed.
32  *     + partition into levels?  Will they be non-crap?
33  *
34  *  - Allow square contents > 9?
35  *     + I could use letters for digits (solo does this), but
36  *       letters don't have numeric significance (normal people hate
37  *       base36), which is relevant here (much more than in solo).
38  *     + [click, 1, 0, enter] => [10 in clicked square]?
39  *     + How much information is needed to solve?  Does one need to
40  *       know the algorithm by which the largest number is set?
41  *
42  *  - eliminate puzzle instances with done chunks (1's in particular)?
43  *     + that's what the qsort call is all about.
44  *     + the 1's don't bother me that much.
45  *     + but this takes a LONG time (not always possible)?
46  *        - this may be affected by solver (lack of) quality.
47  *        - weed them out by construction instead of post-cons check
48  *           + but that interleaves make_board and new_game_desc: you
49  *             have to alternate between changing the board and
50  *             changing the hint set (instead of just creating the
51  *             board once, then changing the hint set once -> done).
52  *
53  *  - use binary search when discovering the minimal sovable point
54  *     + profile to show a need (but when the solver gets slower...)
55  *     + 7x9 @ .011s, 9x13 @ .075s, 17x13 @ .661s (all avg with n=100)
56  *     + but the hints are independent, not linear, so... what?
57  */
58 
59 #include <assert.h>
60 #include <ctype.h>
61 #include <math.h>
62 #include <stdarg.h>
63 #include <stdio.h>
64 #include <stdlib.h>
65 #include <string.h>
66 
67 #include "puzzles.h"
68 
69 static bool verbose;
70 
printv(const char * fmt,...)71 static void printv(const char *fmt, ...) {
72 #ifndef PALM
73     if (verbose) {
74 	va_list va;
75 	va_start(va, fmt);
76 	vprintf(fmt, va);
77 	va_end(va);
78     }
79 #endif
80 }
81 
82 /*****************************************************************************
83  * GAME CONFIGURATION AND PARAMETERS                                         *
84  *****************************************************************************/
85 
86 struct game_params {
87     int w, h;
88 };
89 
90 struct shared_state {
91     struct game_params params;
92     int *clues;
93     int refcnt;
94 };
95 
96 struct game_state {
97     int *board;
98     struct shared_state *shared;
99     bool completed, cheated;
100 };
101 
102 static const struct game_params filling_defaults[3] = {
103     {9, 7}, {13, 9}, {17, 13}
104 };
105 
default_params(void)106 static game_params *default_params(void)
107 {
108     game_params *ret = snew(game_params);
109 
110     *ret = filling_defaults[1]; /* struct copy */
111 
112     return ret;
113 }
114 
game_fetch_preset(int i,char ** name,game_params ** params)115 static bool game_fetch_preset(int i, char **name, game_params **params)
116 {
117     char buf[64];
118 
119     if (i < 0 || i >= lenof(filling_defaults)) return false;
120     *params = snew(game_params);
121     **params = filling_defaults[i]; /* struct copy */
122     sprintf(buf, "%dx%d", filling_defaults[i].w, filling_defaults[i].h);
123     *name = dupstr(buf);
124 
125     return true;
126 }
127 
free_params(game_params * params)128 static void free_params(game_params *params)
129 {
130     sfree(params);
131 }
132 
dup_params(const game_params * params)133 static game_params *dup_params(const game_params *params)
134 {
135     game_params *ret = snew(game_params);
136     *ret = *params; /* struct copy */
137     return ret;
138 }
139 
decode_params(game_params * ret,char const * string)140 static void decode_params(game_params *ret, char const *string)
141 {
142     ret->w = ret->h = atoi(string);
143     while (*string && isdigit((unsigned char) *string)) ++string;
144     if (*string == 'x') ret->h = atoi(++string);
145 }
146 
encode_params(const game_params * params,bool full)147 static char *encode_params(const game_params *params, bool full)
148 {
149     char buf[64];
150     sprintf(buf, "%dx%d", params->w, params->h);
151     return dupstr(buf);
152 }
153 
game_configure(const game_params * params)154 static config_item *game_configure(const game_params *params)
155 {
156     config_item *ret;
157     char buf[64];
158 
159     ret = snewn(3, config_item);
160 
161     ret[0].name = "Width";
162     ret[0].type = C_STRING;
163     sprintf(buf, "%d", params->w);
164     ret[0].u.string.sval = dupstr(buf);
165 
166     ret[1].name = "Height";
167     ret[1].type = C_STRING;
168     sprintf(buf, "%d", params->h);
169     ret[1].u.string.sval = dupstr(buf);
170 
171     ret[2].name = NULL;
172     ret[2].type = C_END;
173 
174     return ret;
175 }
176 
custom_params(const config_item * cfg)177 static game_params *custom_params(const config_item *cfg)
178 {
179     game_params *ret = snew(game_params);
180 
181     ret->w = atoi(cfg[0].u.string.sval);
182     ret->h = atoi(cfg[1].u.string.sval);
183 
184     return ret;
185 }
186 
validate_params(const game_params * params,bool full)187 static const char *validate_params(const game_params *params, bool full)
188 {
189     if (params->w < 1) return "Width must be at least one";
190     if (params->h < 1) return "Height must be at least one";
191 
192     return NULL;
193 }
194 
195 /*****************************************************************************
196  * STRINGIFICATION OF GAME STATE                                             *
197  *****************************************************************************/
198 
199 #define EMPTY 0
200 
201 /* Example of plaintext rendering:
202  *  +---+---+---+---+---+---+---+
203  *  | 6 |   |   | 2 |   |   | 2 |
204  *  +---+---+---+---+---+---+---+
205  *  |   | 3 |   | 6 |   | 3 |   |
206  *  +---+---+---+---+---+---+---+
207  *  | 3 |   |   |   |   |   | 1 |
208  *  +---+---+---+---+---+---+---+
209  *  |   | 2 | 3 |   | 4 | 2 |   |
210  *  +---+---+---+---+---+---+---+
211  *  | 2 |   |   |   |   |   | 3 |
212  *  +---+---+---+---+---+---+---+
213  *  |   | 5 |   | 1 |   | 4 |   |
214  *  +---+---+---+---+---+---+---+
215  *  | 4 |   |   | 3 |   |   | 3 |
216  *  +---+---+---+---+---+---+---+
217  *
218  * This puzzle instance is taken from the nikoli website
219  * Encoded (unsolved and solved), the strings are these:
220  * 7x7:6002002030603030000010230420200000305010404003003
221  * 7x7:6662232336663232331311235422255544325413434443313
222  */
board_to_string(int * board,int w,int h)223 static char *board_to_string(int *board, int w, int h) {
224     const int sz = w * h;
225     const int chw = (4*w + 2); /* +2 for trailing '+' and '\n' */
226     const int chh = (2*h + 1); /* +1: n fence segments, n+1 posts */
227     const int chlen = chw * chh;
228     char *repr = snewn(chlen + 1, char);
229     int i;
230 
231     assert(board);
232 
233     /* build the first line ("^(\+---){n}\+$") */
234     for (i = 0; i < w; ++i) {
235         repr[4*i + 0] = '+';
236         repr[4*i + 1] = '-';
237         repr[4*i + 2] = '-';
238         repr[4*i + 3] = '-';
239     }
240     repr[4*i + 0] = '+';
241     repr[4*i + 1] = '\n';
242 
243     /* ... and copy it onto the odd-numbered lines */
244     for (i = 0; i < h; ++i) memcpy(repr + (2*i + 2) * chw, repr, chw);
245 
246     /* build the second line ("^(\|\t){n}\|$") */
247     for (i = 0; i < w; ++i) {
248         repr[chw + 4*i + 0] = '|';
249         repr[chw + 4*i + 1] = ' ';
250         repr[chw + 4*i + 2] = ' ';
251         repr[chw + 4*i + 3] = ' ';
252     }
253     repr[chw + 4*i + 0] = '|';
254     repr[chw + 4*i + 1] = '\n';
255 
256     /* ... and copy it onto the even-numbered lines */
257     for (i = 1; i < h; ++i) memcpy(repr + (2*i + 1) * chw, repr + chw, chw);
258 
259     /* fill in the numbers */
260     for (i = 0; i < sz; ++i) {
261         const int x = i % w;
262 	const int y = i / w;
263 	if (board[i] == EMPTY) continue;
264 	repr[chw*(2*y + 1) + (4*x + 2)] = board[i] + '0';
265     }
266 
267     repr[chlen] = '\0';
268     return repr;
269 }
270 
game_can_format_as_text_now(const game_params * params)271 static bool game_can_format_as_text_now(const game_params *params)
272 {
273     return true;
274 }
275 
game_text_format(const game_state * state)276 static char *game_text_format(const game_state *state)
277 {
278     const int w = state->shared->params.w;
279     const int h = state->shared->params.h;
280     return board_to_string(state->board, w, h);
281 }
282 
283 /*****************************************************************************
284  * GAME GENERATION AND SOLVER                                                *
285  *****************************************************************************/
286 
287 static const int dx[4] = {-1, 1, 0, 0};
288 static const int dy[4] = {0, 0, -1, 1};
289 
290 struct solver_state
291 {
292     int *dsf;
293     int *board;
294     int *connected;
295     int nempty;
296 
297     /* Used internally by learn_bitmap_deductions; kept here to avoid
298      * mallocing/freeing them every time that function is called. */
299     int *bm, *bmdsf, *bmminsize;
300 };
301 
print_board(int * board,int w,int h)302 static void print_board(int *board, int w, int h) {
303     if (verbose) {
304 	char *repr = board_to_string(board, w, h);
305 	printv("%s\n", repr);
306 	free(repr);
307     }
308 }
309 
310 static game_state *new_game(midend *, const game_params *, const char *);
311 static void free_game(game_state *);
312 
313 #define SENTINEL (sz+1)
314 
mark_region(int * board,int w,int h,int i,int n,int m)315 static bool mark_region(int *board, int w, int h, int i, int n, int m) {
316     int j;
317 
318     board[i] = -1;
319 
320     for (j = 0; j < 4; ++j) {
321         const int x = (i % w) + dx[j], y = (i / w) + dy[j], ii = w*y + x;
322         if (x < 0 || x >= w || y < 0 || y >= h) continue;
323         if (board[ii] == m) return false;
324         if (board[ii] != n) continue;
325         if (!mark_region(board, w, h, ii, n, m)) return false;
326     }
327     return true;
328 }
329 
region_size(int * board,int w,int h,int i)330 static int region_size(int *board, int w, int h, int i) {
331     const int sz = w * h;
332     int j, size, copy;
333     if (board[i] == 0) return 0;
334     copy = board[i];
335     mark_region(board, w, h, i, board[i], SENTINEL);
336     for (size = j = 0; j < sz; ++j) {
337         if (board[j] != -1) continue;
338         ++size;
339         board[j] = copy;
340     }
341     return size;
342 }
343 
merge_ones(int * board,int w,int h)344 static void merge_ones(int *board, int w, int h)
345 {
346     const int sz = w * h;
347     const int maxsize = min(max(max(w, h), 3), 9);
348     int i, j, k;
349     bool change;
350     do {
351         change = false;
352         for (i = 0; i < sz; ++i) {
353             if (board[i] != 1) continue;
354 
355             for (j = 0; j < 4; ++j, board[i] = 1) {
356                 const int x = (i % w) + dx[j], y = (i / w) + dy[j];
357                 int oldsize, newsize, ii = w*y + x;
358 		bool ok;
359 
360                 if (x < 0 || x >= w || y < 0 || y >= h) continue;
361                 if (board[ii] == maxsize) continue;
362 
363                 oldsize = board[ii];
364                 board[i] = oldsize;
365                 newsize = region_size(board, w, h, i);
366 
367                 if (newsize > maxsize) continue;
368 
369                 ok = mark_region(board, w, h, i, oldsize, newsize);
370 
371                 for (k = 0; k < sz; ++k)
372                     if (board[k] == -1)
373                         board[k] = ok ? newsize : oldsize;
374 
375                 if (ok) break;
376             }
377             if (j < 4) change = true;
378         }
379     } while (change);
380 }
381 
382 /* generate a random valid board; uses validate_board. */
make_board(int * board,int w,int h,random_state * rs)383 static void make_board(int *board, int w, int h, random_state *rs) {
384     const int sz = w * h;
385 
386     /* w=h=2 is a special case which requires a number > max(w, h) */
387     /* TODO prove that this is the case ONLY for w=h=2. */
388     const int maxsize = min(max(max(w, h), 3), 9);
389 
390     /* Note that if 1 in {w, h} then it's impossible to have a region
391      * of size > w*h, so the special case only affects w=h=2. */
392 
393     int i, *dsf;
394     bool change;
395 
396     assert(w >= 1);
397     assert(h >= 1);
398     assert(board);
399 
400     /* I abuse the board variable: when generating the puzzle, it
401      * contains a shuffled list of numbers {0, ..., sz-1}. */
402     for (i = 0; i < sz; ++i) board[i] = i;
403 
404     dsf = snewn(sz, int);
405 retry:
406     dsf_init(dsf, sz);
407     shuffle(board, sz, sizeof (int), rs);
408 
409     do {
410         change = false; /* as long as the board potentially has errors */
411         for (i = 0; i < sz; ++i) {
412             const int square = dsf_canonify(dsf, board[i]);
413             const int size = dsf_size(dsf, square);
414             int merge = SENTINEL, min = maxsize - size + 1;
415 	    bool error = false;
416             int neighbour, neighbour_size, j;
417 	    int directions[4];
418 
419             for (j = 0; j < 4; ++j)
420 		directions[j] = j;
421 	    shuffle(directions, 4, sizeof(int), rs);
422 
423             for (j = 0; j < 4; ++j) {
424                 const int x = (board[i] % w) + dx[directions[j]];
425                 const int y = (board[i] / w) + dy[directions[j]];
426                 if (x < 0 || x >= w || y < 0 || y >= h) continue;
427 
428                 neighbour = dsf_canonify(dsf, w*y + x);
429                 if (square == neighbour) continue;
430 
431                 neighbour_size = dsf_size(dsf, neighbour);
432                 if (size == neighbour_size) error = true;
433 
434                 /* find the smallest neighbour to merge with, which
435                  * wouldn't make the region too large.  (This is
436                  * guaranteed by the initial value of `min'.) */
437                 if (neighbour_size < min && random_upto(rs, 10)) {
438                     min = neighbour_size;
439                     merge = neighbour;
440                 }
441             }
442 
443             /* if this square is not in error, leave it be */
444             if (!error) continue;
445 
446             /* if it is, but we can't fix it, retry the whole board.
447              * Maybe we could fix it by merging the conflicting
448              * neighbouring region(s) into some of their neighbours,
449              * but just restarting works out fine. */
450             if (merge == SENTINEL) goto retry;
451 
452             /* merge with the smallest neighbouring workable region. */
453             dsf_merge(dsf, square, merge);
454             change = true;
455         }
456     } while (change);
457 
458     for (i = 0; i < sz; ++i) board[i] = dsf_size(dsf, i);
459     merge_ones(board, w, h);
460 
461     sfree(dsf);
462 }
463 
merge(int * dsf,int * connected,int a,int b)464 static void merge(int *dsf, int *connected, int a, int b) {
465     int c;
466     assert(dsf);
467     assert(connected);
468     a = dsf_canonify(dsf, a);
469     b = dsf_canonify(dsf, b);
470     if (a == b) return;
471     dsf_merge(dsf, a, b);
472     c = connected[a];
473     connected[a] = connected[b];
474     connected[b] = c;
475 }
476 
memdup(const void * ptr,size_t len,size_t esz)477 static void *memdup(const void *ptr, size_t len, size_t esz) {
478     void *dup = smalloc(len * esz);
479     assert(ptr);
480     memcpy(dup, ptr, len * esz);
481     return dup;
482 }
483 
expand(struct solver_state * s,int w,int h,int t,int f)484 static void expand(struct solver_state *s, int w, int h, int t, int f) {
485     int j;
486     assert(s);
487     assert(s->board[t] == EMPTY); /* expand to empty square */
488     assert(s->board[f] != EMPTY); /* expand from non-empty square */
489     printv(
490 	"learn: expanding %d from (%d, %d) into (%d, %d)\n",
491 	s->board[f], f % w, f / w, t % w, t / w);
492     s->board[t] = s->board[f];
493     for (j = 0; j < 4; ++j) {
494         const int x = (t % w) + dx[j];
495         const int y = (t / w) + dy[j];
496         const int idx = w*y + x;
497         if (x < 0 || x >= w || y < 0 || y >= h) continue;
498         if (s->board[idx] != s->board[t]) continue;
499         merge(s->dsf, s->connected, t, idx);
500     }
501     --s->nempty;
502 }
503 
clear_count(int * board,int sz)504 static void clear_count(int *board, int sz) {
505     int i;
506     for (i = 0; i < sz; ++i) {
507         if (board[i] >= 0) continue;
508         else if (board[i] == -SENTINEL) board[i] = EMPTY;
509         else board[i] = -board[i];
510     }
511 }
512 
flood_count(int * board,int w,int h,int i,int n,int * c)513 static void flood_count(int *board, int w, int h, int i, int n, int *c) {
514     const int sz = w * h;
515     int k;
516 
517     if (board[i] == EMPTY) board[i] = -SENTINEL;
518     else if (board[i] == n) board[i] = -board[i];
519     else return;
520 
521     if (--*c == 0) return;
522 
523     for (k = 0; k < 4; ++k) {
524         const int x = (i % w) + dx[k];
525         const int y = (i / w) + dy[k];
526         const int idx = w*y + x;
527         if (x < 0 || x >= w || y < 0 || y >= h) continue;
528         flood_count(board, w, h, idx, n, c);
529 	if (*c == 0) return;
530     }
531 }
532 
check_capacity(int * board,int w,int h,int i)533 static bool check_capacity(int *board, int w, int h, int i) {
534     int n = board[i];
535     flood_count(board, w, h, i, board[i], &n);
536     clear_count(board, w * h);
537     return n == 0;
538 }
539 
expandsize(const int * board,int * dsf,int w,int h,int i,int n)540 static int expandsize(const int *board, int *dsf, int w, int h, int i, int n) {
541     int j;
542     int nhits = 0;
543     int hits[4];
544     int size = 1;
545     for (j = 0; j < 4; ++j) {
546         const int x = (i % w) + dx[j];
547         const int y = (i / w) + dy[j];
548         const int idx = w*y + x;
549         int root;
550         int m;
551         if (x < 0 || x >= w || y < 0 || y >= h) continue;
552         if (board[idx] != n) continue;
553         root = dsf_canonify(dsf, idx);
554         for (m = 0; m < nhits && root != hits[m]; ++m);
555         if (m < nhits) continue;
556 	printv("\t  (%d, %d) contrib %d to size\n", x, y, dsf[root] >> 2);
557         size += dsf_size(dsf, root);
558         assert(dsf_size(dsf, root) >= 1);
559         hits[nhits++] = root;
560     }
561     return size;
562 }
563 
564 /*
565  *  +---+---+---+---+---+---+---+
566  *  | 6 |   |   | 2 |   |   | 2 |
567  *  +---+---+---+---+---+---+---+
568  *  |   | 3 |   | 6 |   | 3 |   |
569  *  +---+---+---+---+---+---+---+
570  *  | 3 |   |   |   |   |   | 1 |
571  *  +---+---+---+---+---+---+---+
572  *  |   | 2 | 3 |   | 4 | 2 |   |
573  *  +---+---+---+---+---+---+---+
574  *  | 2 |   |   |   |   |   | 3 |
575  *  +---+---+---+---+---+---+---+
576  *  |   | 5 |   | 1 |   | 4 |   |
577  *  +---+---+---+---+---+---+---+
578  *  | 4 |   |   | 3 |   |   | 3 |
579  *  +---+---+---+---+---+---+---+
580  */
581 
582 /* Solving techniques:
583  *
584  * CONNECTED COMPONENT FORCED EXPANSION (too big):
585  * When a CC can only be expanded in one direction, because all the
586  * other ones would make the CC too big.
587  *  +---+---+---+---+---+
588  *  | 2 | 2 |   | 2 | _ |
589  *  +---+---+---+---+---+
590  *
591  * CONNECTED COMPONENT FORCED EXPANSION (too small):
592  * When a CC must include a particular square, because otherwise there
593  * would not be enough room to complete it.  This includes squares not
594  * adjacent to the CC through learn_critical_square.
595  *  +---+---+
596  *  | 2 | _ |
597  *  +---+---+
598  *
599  * DROPPING IN A ONE:
600  * When an empty square has no neighbouring empty squares and only a 1
601  * will go into the square (or other CCs would be too big).
602  *  +---+---+---+
603  *  | 2 | 2 | _ |
604  *  +---+---+---+
605  *
606  * TODO: generalise DROPPING IN A ONE: find the size of the CC of
607  * empty squares and a list of all adjacent numbers.  See if only one
608  * number in {1, ..., size} u {all adjacent numbers} is possible.
609  * Probably this is only effective for a CC size < n for some n (4?)
610  *
611  * TODO: backtracking.
612  */
613 
filled_square(struct solver_state * s,int w,int h,int i)614 static void filled_square(struct solver_state *s, int w, int h, int i) {
615     int j;
616     for (j = 0; j < 4; ++j) {
617 	const int x = (i % w) + dx[j];
618 	const int y = (i / w) + dy[j];
619 	const int idx = w*y + x;
620 	if (x < 0 || x >= w || y < 0 || y >= h) continue;
621 	if (s->board[i] == s->board[idx])
622 	    merge(s->dsf, s->connected, i, idx);
623     }
624 }
625 
init_solver_state(struct solver_state * s,int w,int h)626 static void init_solver_state(struct solver_state *s, int w, int h) {
627     const int sz = w * h;
628     int i;
629     assert(s);
630 
631     s->nempty = 0;
632     for (i = 0; i < sz; ++i) s->connected[i] = i;
633     for (i = 0; i < sz; ++i)
634         if (s->board[i] == EMPTY) ++s->nempty;
635         else filled_square(s, w, h, i);
636 }
637 
learn_expand_or_one(struct solver_state * s,int w,int h)638 static bool learn_expand_or_one(struct solver_state *s, int w, int h) {
639     const int sz = w * h;
640     int i;
641     bool learn = false;
642 
643     assert(s);
644 
645     for (i = 0; i < sz; ++i) {
646 	int j;
647 	bool one = true;
648 
649 	if (s->board[i] != EMPTY) continue;
650 
651 	for (j = 0; j < 4; ++j) {
652 	    const int x = (i % w) + dx[j];
653 	    const int y = (i / w) + dy[j];
654 	    const int idx = w*y + x;
655 	    if (x < 0 || x >= w || y < 0 || y >= h) continue;
656 	    if (s->board[idx] == EMPTY) {
657 		one = false;
658 		continue;
659 	    }
660 	    if (one &&
661 		(s->board[idx] == 1 ||
662 		 (s->board[idx] >= expandsize(s->board, s->dsf, w, h,
663 					      i, s->board[idx]))))
664 		one = false;
665 	    if (dsf_size(s->dsf, idx) == s->board[idx]) continue;
666 	    assert(s->board[i] == EMPTY);
667 	    s->board[i] = -SENTINEL;
668 	    if (check_capacity(s->board, w, h, idx)) continue;
669 	    assert(s->board[i] == EMPTY);
670 	    printv("learn: expanding in one\n");
671 	    expand(s, w, h, i, idx);
672 	    learn = true;
673 	    break;
674 	}
675 
676 	if (j == 4 && one) {
677 	    printv("learn: one at (%d, %d)\n", i % w, i / w);
678 	    assert(s->board[i] == EMPTY);
679 	    s->board[i] = 1;
680 	    assert(s->nempty);
681 	    --s->nempty;
682 	    learn = true;
683 	}
684     }
685     return learn;
686 }
687 
learn_blocked_expansion(struct solver_state * s,int w,int h)688 static bool learn_blocked_expansion(struct solver_state *s, int w, int h) {
689     const int sz = w * h;
690     int i;
691     bool learn = false;
692 
693     assert(s);
694     /* for every connected component */
695     for (i = 0; i < sz; ++i) {
696         int exp = SENTINEL;
697         int j;
698 
699 	if (s->board[i] == EMPTY) continue;
700         j = dsf_canonify(s->dsf, i);
701 
702         /* (but only for each connected component) */
703         if (i != j) continue;
704 
705         /* (and not if it's already complete) */
706         if (dsf_size(s->dsf, j) == s->board[j]) continue;
707 
708         /* for each square j _in_ the connected component */
709         do {
710             int k;
711             printv("  looking at (%d, %d)\n", j % w, j / w);
712 
713             /* for each neighbouring square (idx) */
714             for (k = 0; k < 4; ++k) {
715                 const int x = (j % w) + dx[k];
716                 const int y = (j / w) + dy[k];
717                 const int idx = w*y + x;
718                 int size;
719                 /* int l;
720                    int nhits = 0;
721                    int hits[4]; */
722                 if (x < 0 || x >= w || y < 0 || y >= h) continue;
723                 if (s->board[idx] != EMPTY) continue;
724                 if (exp == idx) continue;
725                 printv("\ttrying to expand onto (%d, %d)\n", x, y);
726 
727                 /* find out the would-be size of the new connected
728                  * component if we actually expanded into idx */
729                 /*
730                 size = 1;
731                 for (l = 0; l < 4; ++l) {
732                     const int lx = x + dx[l];
733                     const int ly = y + dy[l];
734                     const int idxl = w*ly + lx;
735                     int root;
736                     int m;
737                     if (lx < 0 || lx >= w || ly < 0 || ly >= h) continue;
738                     if (board[idxl] != board[j]) continue;
739                     root = dsf_canonify(dsf, idxl);
740                     for (m = 0; m < nhits && root != hits[m]; ++m);
741                     if (m != nhits) continue;
742                     // printv("\t  (%d, %d) contributed %d to size\n", lx, ly, dsf[root] >> 2);
743                     size += dsf_size(dsf, root);
744                     assert(dsf_size(dsf, root) >= 1);
745                     hits[nhits++] = root;
746                 }
747                 */
748 
749                 size = expandsize(s->board, s->dsf, w, h, idx, s->board[j]);
750 
751                 /* ... and see if that size is too big, or if we
752                  * have other expansion candidates.  Otherwise
753                  * remember the (so far) only candidate. */
754 
755                 printv("\tthat would give a size of %d\n", size);
756                 if (size > s->board[j]) continue;
757                 /* printv("\tnow knowing %d expansions\n", nexpand + 1); */
758                 if (exp != SENTINEL) goto next_i;
759                 assert(exp != idx);
760                 exp = idx;
761             }
762 
763             j = s->connected[j]; /* next square in the same CC */
764             assert(s->board[i] == s->board[j]);
765         } while (j != i);
766         /* end: for each square j _in_ the connected component */
767 
768 	if (exp == SENTINEL) continue;
769 	printv("learning to expand\n");
770 	expand(s, w, h, exp, i);
771 	learn = true;
772 
773         next_i:
774         ;
775     }
776     /* end: for each connected component */
777     return learn;
778 }
779 
learn_critical_square(struct solver_state * s,int w,int h)780 static bool learn_critical_square(struct solver_state *s, int w, int h) {
781     const int sz = w * h;
782     int i;
783     bool learn = false;
784     assert(s);
785 
786     /* for each connected component */
787     for (i = 0; i < sz; ++i) {
788 	int j, slack;
789 	if (s->board[i] == EMPTY) continue;
790 	if (i != dsf_canonify(s->dsf, i)) continue;
791 	slack = s->board[i] - dsf_size(s->dsf, i);
792 	if (slack == 0) continue;
793 	assert(s->board[i] != 1);
794 	/* for each empty square */
795 	for (j = 0; j < sz; ++j) {
796 	    if (s->board[j] == EMPTY) {
797 		/* if it's too far away from the CC, don't bother */
798 		int k = i, jx = j % w, jy = j / w;
799 		do {
800 		    int kx = k % w, ky = k / w;
801 		    if (abs(kx - jx) + abs(ky - jy) <= slack) break;
802 		    k = s->connected[k];
803 		} while (i != k);
804 		if (i == k) continue; /* not within range */
805 	    } else continue;
806 	    s->board[j] = -SENTINEL;
807 	    if (check_capacity(s->board, w, h, i)) continue;
808 	    /* if not expanding s->board[i] to s->board[j] implies
809 	     * that s->board[i] can't reach its full size, ... */
810 	    assert(s->nempty);
811 	    printv(
812 		"learn: ds %d at (%d, %d) blocking (%d, %d)\n",
813 		s->board[i], j % w, j / w, i % w, i / w);
814 	    --s->nempty;
815 	    s->board[j] = s->board[i];
816 	    filled_square(s, w, h, j);
817 	    learn = true;
818 	}
819     }
820     return learn;
821 }
822 
823 #if 0
824 static void print_bitmap(int *bitmap, int w, int h) {
825     if (verbose) {
826 	int x, y;
827 	for (y = 0; y < h; y++) {
828 	    for (x = 0; x < w; x++) {
829 		printv(" %03x", bm[y*w+x]);
830 	    }
831 	    printv("\n");
832 	}
833     }
834 }
835 #endif
836 
learn_bitmap_deductions(struct solver_state * s,int w,int h)837 static bool learn_bitmap_deductions(struct solver_state *s, int w, int h)
838 {
839     const int sz = w * h;
840     int *bm = s->bm;
841     int *dsf = s->bmdsf;
842     int *minsize = s->bmminsize;
843     int x, y, i, j, n;
844     bool learn = false;
845 
846     /*
847      * This function does deductions based on building up a bitmap
848      * which indicates the possible numbers that can appear in each
849      * grid square. If we can rule out all but one possibility for a
850      * particular square, then we've found out the value of that
851      * square. In particular, this is one of the few forms of
852      * deduction capable of inferring the existence of a 'ghost
853      * region', i.e. a region which has none of its squares filled in
854      * at all.
855      *
856      * The reasoning goes like this. A currently unfilled square S can
857      * turn out to contain digit n in exactly two ways: either S is
858      * part of an n-region which also includes some currently known
859      * connected component of squares with n in, or S is part of an
860      * n-region separate from _all_ currently known connected
861      * components. If we can rule out both possibilities, then square
862      * S can't contain digit n at all.
863      *
864      * The former possibility: if there's a region of size n
865      * containing both S and some existing component C, then that
866      * means the distance from S to C must be small enough that C
867      * could be extended to include S without becoming too big. So we
868      * can do a breadth-first search out from all existing components
869      * with n in them, to identify all the squares which could be
870      * joined to any of them.
871      *
872      * The latter possibility: if there's a region of size n that
873      * doesn't contain _any_ existing component, then it also can't
874      * contain any square adjacent to an existing component either. So
875      * we can identify all the EMPTY squares not adjacent to any
876      * existing square with n in, and group them into connected
877      * components; then any component of size less than n is ruled
878      * out, because there wouldn't be room to create a completely new
879      * n-region in it.
880      *
881      * In fact we process these possibilities in the other order.
882      * First we find all the squares not adjacent to an existing
883      * square with n in; then we winnow those by removing too-small
884      * connected components, to get the set of squares which could
885      * possibly be part of a brand new n-region; and finally we do the
886      * breadth-first search to add in the set of squares which could
887      * possibly be added to some existing n-region.
888      */
889 
890     /*
891      * Start by initialising our bitmap to 'all numbers possible in
892      * all squares'.
893      */
894     for (y = 0; y < h; y++)
895 	for (x = 0; x < w; x++)
896 	    bm[y*w+x] = (1 << 10) - (1 << 1); /* bits 1,2,...,9 now set */
897 #if 0
898     printv("initial bitmap:\n");
899     print_bitmap(bm, w, h);
900 #endif
901 
902     /*
903      * Now completely zero out the bitmap for squares that are already
904      * filled in (we aren't interested in those anyway). Also, for any
905      * filled square, eliminate its number from all its neighbours
906      * (because, as discussed above, the neighbours couldn't be part
907      * of a _new_ region with that number in it, and that's the case
908      * we consider first).
909      */
910     for (y = 0; y < h; y++) {
911 	for (x = 0; x < w; x++) {
912 	    i = y*w+x;
913 	    n = s->board[i];
914 
915 	    if (n != EMPTY) {
916 		bm[i] = 0;
917 
918 		if (x > 0)
919 		    bm[i-1] &= ~(1 << n);
920 		if (x+1 < w)
921 		    bm[i+1] &= ~(1 << n);
922 		if (y > 0)
923 		    bm[i-w] &= ~(1 << n);
924 		if (y+1 < h)
925 		    bm[i+w] &= ~(1 << n);
926 	    }
927 	}
928     }
929 #if 0
930     printv("bitmap after filled squares:\n");
931     print_bitmap(bm, w, h);
932 #endif
933 
934     /*
935      * Now, for each n, we separately find the connected components of
936      * squares for which n is still a possibility. Then discard any
937      * component of size < n, because that component is too small to
938      * have a completely new n-region in it.
939      */
940     for (n = 1; n <= 9; n++) {
941 	dsf_init(dsf, sz);
942 
943 	/* Build the dsf */
944 	for (y = 0; y < h; y++)
945 	    for (x = 0; x+1 < w; x++)
946 		if (bm[y*w+x] & bm[y*w+(x+1)] & (1 << n))
947 		    dsf_merge(dsf, y*w+x, y*w+(x+1));
948 	for (y = 0; y+1 < h; y++)
949 	    for (x = 0; x < w; x++)
950 		if (bm[y*w+x] & bm[(y+1)*w+x] & (1 << n))
951 		    dsf_merge(dsf, y*w+x, (y+1)*w+x);
952 
953 	/* Query the dsf */
954 	for (i = 0; i < sz; i++)
955 	    if ((bm[i] & (1 << n)) && dsf_size(dsf, i) < n)
956 		bm[i] &= ~(1 << n);
957     }
958 #if 0
959     printv("bitmap after winnowing small components:\n");
960     print_bitmap(bm, w, h);
961 #endif
962 
963     /*
964      * Now our bitmap includes every square which could be part of a
965      * completely new region, of any size. Extend it to include
966      * squares which could be part of an existing region.
967      */
968     for (n = 1; n <= 9; n++) {
969 	/*
970 	 * We're going to do a breadth-first search starting from
971 	 * existing connected components with cell value n, to find
972 	 * all cells they might possibly extend into.
973 	 *
974 	 * The quantity we compute, for each square, is 'minimum size
975 	 * that any existing CC would have to have if extended to
976 	 * include this square'. So squares already _in_ an existing
977 	 * CC are initialised to the size of that CC; then we search
978 	 * outwards using the rule that if a square's score is j, then
979 	 * its neighbours can't score more than j+1.
980 	 *
981 	 * Scores are capped at n+1, because if a square scores more
982 	 * than n then that's enough to know it can't possibly be
983 	 * reached by extending an existing region - we don't need to
984 	 * know exactly _how far_ out of reach it is.
985 	 */
986 	for (i = 0; i < sz; i++) {
987 	    if (s->board[i] == n) {
988 		/* Square is part of an existing CC. */
989 		minsize[i] = dsf_size(s->dsf, i);
990 	    } else {
991 		/* Otherwise, initialise to the maximum score n+1;
992 		 * we'll reduce this later if we find a neighbouring
993 		 * square with a lower score. */
994 		minsize[i] = n+1;
995 	    }
996 	}
997 
998 	for (j = 1; j < n; j++) {
999 	    /*
1000 	     * Find neighbours of cells scoring j, and set their score
1001 	     * to at most j+1.
1002 	     *
1003 	     * Doing the BFS this way means we need n passes over the
1004 	     * grid, which isn't entirely optimal but it seems to be
1005 	     * fast enough for the moment. This could probably be
1006 	     * improved by keeping a linked-list queue of cells in
1007 	     * some way, but I think you'd have to be a bit careful to
1008 	     * insert things into the right place in the queue; this
1009 	     * way is easier not to get wrong.
1010 	     */
1011 	    for (y = 0; y < h; y++) {
1012 		for (x = 0; x < w; x++) {
1013 		    i = y*w+x;
1014 		    if (minsize[i] == j) {
1015 			if (x > 0 && minsize[i-1] > j+1)
1016 			    minsize[i-1] = j+1;
1017 			if (x+1 < w && minsize[i+1] > j+1)
1018 			    minsize[i+1] = j+1;
1019 			if (y > 0 && minsize[i-w] > j+1)
1020 			    minsize[i-w] = j+1;
1021 			if (y+1 < h && minsize[i+w] > j+1)
1022 			    minsize[i+w] = j+1;
1023 		    }
1024 		}
1025 	    }
1026 	}
1027 
1028 	/*
1029 	 * Now, every cell scoring at most n should have its 1<<n bit
1030 	 * in the bitmap reinstated, because we've found that it's
1031 	 * potentially reachable by extending an existing CC.
1032 	 */
1033 	for (i = 0; i < sz; i++)
1034 	    if (minsize[i] <= n)
1035 		bm[i] |= 1<<n;
1036     }
1037 #if 0
1038     printv("bitmap after bfs:\n");
1039     print_bitmap(bm, w, h);
1040 #endif
1041 
1042     /*
1043      * Now our bitmap is complete. Look for entries with only one bit
1044      * set; those are squares with only one possible number, in which
1045      * case we can fill that number in.
1046      */
1047     for (i = 0; i < sz; i++) {
1048 	if (bm[i] && !(bm[i] & (bm[i]-1))) { /* is bm[i] a power of two? */
1049 	    int val = bm[i];
1050 
1051 	    /* Integer log2, by simple binary search. */
1052 	    n = 0;
1053 	    if (val >> 8) { val >>= 8; n += 8; }
1054 	    if (val >> 4) { val >>= 4; n += 4; }
1055 	    if (val >> 2) { val >>= 2; n += 2; }
1056 	    if (val >> 1) { val >>= 1; n += 1; }
1057 
1058 	    /* Double-check that we ended up with a sensible
1059 	     * answer. */
1060 	    assert(1 <= n);
1061 	    assert(n <= 9);
1062 	    assert(bm[i] == (1 << n));
1063 
1064 	    if (s->board[i] == EMPTY) {
1065 		printv("learn: %d is only possibility at (%d, %d)\n",
1066 		       n, i % w, i / w);
1067 		s->board[i] = n;
1068 		filled_square(s, w, h, i);
1069 		assert(s->nempty);
1070 		--s->nempty;
1071 		learn = true;
1072 	    }
1073 	}
1074     }
1075 
1076     return learn;
1077 }
1078 
solver(const int * orig,int w,int h,char ** solution)1079 static bool solver(const int *orig, int w, int h, char **solution) {
1080     const int sz = w * h;
1081 
1082     struct solver_state ss;
1083     ss.board = memdup(orig, sz, sizeof (int));
1084     ss.dsf = snew_dsf(sz); /* eqv classes: connected components */
1085     ss.connected = snewn(sz, int); /* connected[n] := n.next; */
1086     /* cyclic disjoint singly linked lists, same partitioning as dsf.
1087      * The lists lets you iterate over a partition given any member */
1088     ss.bm = snewn(sz, int);
1089     ss.bmdsf = snew_dsf(sz);
1090     ss.bmminsize = snewn(sz, int);
1091 
1092     printv("trying to solve this:\n");
1093     print_board(ss.board, w, h);
1094 
1095     init_solver_state(&ss, w, h);
1096     do {
1097 	if (learn_blocked_expansion(&ss, w, h)) continue;
1098 	if (learn_expand_or_one(&ss, w, h)) continue;
1099 	if (learn_critical_square(&ss, w, h)) continue;
1100 	if (learn_bitmap_deductions(&ss, w, h)) continue;
1101 	break;
1102     } while (ss.nempty);
1103 
1104     printv("best guess:\n");
1105     print_board(ss.board, w, h);
1106 
1107     if (solution) {
1108         int i;
1109         *solution = snewn(sz + 2, char);
1110         **solution = 's';
1111         for (i = 0; i < sz; ++i) (*solution)[i + 1] = ss.board[i] + '0';
1112         (*solution)[sz + 1] = '\0';
1113         /* We don't need the \0 for execute_move (the only user)
1114          * I'm just being printf-friendly in case I wanna print */
1115     }
1116 
1117     sfree(ss.dsf);
1118     sfree(ss.board);
1119     sfree(ss.connected);
1120     sfree(ss.bm);
1121     sfree(ss.bmdsf);
1122     sfree(ss.bmminsize);
1123 
1124     return !ss.nempty;
1125 }
1126 
make_dsf(int * dsf,int * board,const int w,const int h)1127 static int *make_dsf(int *dsf, int *board, const int w, const int h) {
1128     const int sz = w * h;
1129     int i;
1130 
1131     if (!dsf)
1132         dsf = snew_dsf(w * h);
1133     else
1134         dsf_init(dsf, w * h);
1135 
1136     for (i = 0; i < sz; ++i) {
1137         int j;
1138         for (j = 0; j < 4; ++j) {
1139             const int x = (i % w) + dx[j];
1140             const int y = (i / w) + dy[j];
1141             const int k = w*y + x;
1142             if (x < 0 || x >= w || y < 0 || y >= h) continue;
1143             if (board[i] == board[k]) dsf_merge(dsf, i, k);
1144         }
1145     }
1146     return dsf;
1147 }
1148 
minimize_clue_set(int * board,int w,int h,random_state * rs)1149 static void minimize_clue_set(int *board, int w, int h, random_state *rs)
1150 {
1151     const int sz = w * h;
1152     int *shuf = snewn(sz, int), i;
1153     int *dsf, *next;
1154 
1155     for (i = 0; i < sz; ++i) shuf[i] = i;
1156     shuffle(shuf, sz, sizeof (int), rs);
1157 
1158     /*
1159      * First, try to eliminate an entire region at a time if possible,
1160      * because inferring the existence of a completely unclued region
1161      * is a particularly good aspect of this puzzle type and we want
1162      * to encourage it to happen.
1163      *
1164      * Begin by identifying the regions as linked lists of cells using
1165      * the 'next' array.
1166      */
1167     dsf = make_dsf(NULL, board, w, h);
1168     next = snewn(sz, int);
1169     for (i = 0; i < sz; ++i) {
1170 	int j = dsf_canonify(dsf, i);
1171 	if (i == j) {
1172 	    /* First cell of a region; set next[i] = -1 to indicate
1173 	     * end-of-list. */
1174 	    next[i] = -1;
1175 	} else {
1176 	    /* Add this cell to a region which already has a
1177 	     * linked-list head, by pointing the canonical element j
1178 	     * at this one, and pointing this one in turn at wherever
1179 	     * j previously pointed. (This should end up with the
1180 	     * elements linked in the order 1,n,n-1,n-2,...,2, which
1181 	     * is a bit weird-looking, but any order is fine.)
1182 	     */
1183 	    assert(j < i);
1184 	    next[i] = next[j];
1185 	    next[j] = i;
1186 	}
1187     }
1188 
1189     /*
1190      * Now loop over the grid cells in our shuffled order, and each
1191      * time we encounter a region for the first time, try to remove it
1192      * all. Then we set next[canonical index] to -2 rather than -1, to
1193      * mark it as already tried.
1194      *
1195      * Doing this in a loop over _cells_, rather than extracting and
1196      * shuffling a list of _regions_, is intended to skew the
1197      * probabilities towards trying to remove larger regions first
1198      * (but without anything as crudely predictable as enforcing that
1199      * we _always_ process regions in descending size order). Region
1200      * removals might well be mutually exclusive, and larger ghost
1201      * regions are more interesting, so we want to bias towards them
1202      * if we can.
1203      */
1204     for (i = 0; i < sz; ++i) {
1205 	int j = dsf_canonify(dsf, shuf[i]);
1206 	if (next[j] != -2) {
1207 	    int tmp = board[j];
1208 	    int k;
1209 
1210 	    /* Blank out the whole thing. */
1211 	    for (k = j; k >= 0; k = next[k])
1212 		board[k] = EMPTY;
1213 
1214 	    if (!solver(board, w, h, NULL)) {
1215 		/* Wasn't still solvable; reinstate it all */
1216 		for (k = j; k >= 0; k = next[k])
1217 		    board[k] = tmp;
1218 	    }
1219 
1220 	    /* Either way, don't try this region again. */
1221 	    next[j] = -2;
1222 	}
1223     }
1224     sfree(next);
1225     sfree(dsf);
1226 
1227     /*
1228      * Now go through individual cells, in the same shuffled order,
1229      * and try to remove each one by itself.
1230      */
1231     for (i = 0; i < sz; ++i) {
1232         int tmp = board[shuf[i]];
1233         board[shuf[i]] = EMPTY;
1234         if (!solver(board, w, h, NULL)) board[shuf[i]] = tmp;
1235     }
1236 
1237     sfree(shuf);
1238 }
1239 
encode_run(char * buffer,int run)1240 static int encode_run(char *buffer, int run)
1241 {
1242     int i = 0;
1243     for (; run > 26; run -= 26)
1244 	buffer[i++] = 'z';
1245     if (run)
1246 	buffer[i++] = 'a' - 1 + run;
1247     return i;
1248 }
1249 
new_game_desc(const game_params * params,random_state * rs,char ** aux,bool interactive)1250 static char *new_game_desc(const game_params *params, random_state *rs,
1251                            char **aux, bool interactive)
1252 {
1253     const int w = params->w, h = params->h, sz = w * h;
1254     int *board = snewn(sz, int), i, j, run;
1255     char *description = snewn(sz + 1, char);
1256 
1257     make_board(board, w, h, rs);
1258     minimize_clue_set(board, w, h, rs);
1259 
1260     for (run = j = i = 0; i < sz; ++i) {
1261         assert(board[i] >= 0);
1262         assert(board[i] < 10);
1263 	if (board[i] == 0) {
1264 	    ++run;
1265 	} else {
1266 	    j += encode_run(description + j, run);
1267 	    run = 0;
1268 	    description[j++] = board[i] + '0';
1269 	}
1270     }
1271     j += encode_run(description + j, run);
1272     description[j++] = '\0';
1273 
1274     sfree(board);
1275 
1276     return sresize(description, j, char);
1277 }
1278 
validate_desc(const game_params * params,const char * desc)1279 static const char *validate_desc(const game_params *params, const char *desc)
1280 {
1281     const int sz = params->w * params->h;
1282     const char m = '0' + max(max(params->w, params->h), 3);
1283     int area;
1284 
1285     for (area = 0; *desc; ++desc) {
1286 	if (*desc >= 'a' && *desc <= 'z') area += *desc - 'a' + 1;
1287 	else if (*desc >= '0' && *desc <= m) ++area;
1288 	else {
1289 	    static char s[] =  "Invalid character '%""' in game description";
1290 	    int n = sprintf(s, "Invalid character '%1c' in game description",
1291 			    *desc);
1292 	    assert(n + 1 <= lenof(s)); /* +1 for the terminating NUL */
1293 	    return s;
1294 	}
1295 	if (area > sz) return "Too much data to fit in grid";
1296     }
1297     return (area < sz) ? "Not enough data to fill grid" : NULL;
1298 }
1299 
game_request_keys(const game_params * params,int * nkeys)1300 static key_label *game_request_keys(const game_params *params, int *nkeys)
1301 {
1302     int i;
1303     key_label *keys = snewn(11, key_label);
1304 
1305     *nkeys = 11;
1306 
1307     for(i = 0; i < 10; ++i)
1308     {
1309 	keys[i].button = '0' + i;
1310 	keys[i].label = NULL;
1311     }
1312     keys[10].button = '\b';
1313     keys[10].label = NULL;
1314 
1315     return keys;
1316 }
1317 
new_game(midend * me,const game_params * params,const char * desc)1318 static game_state *new_game(midend *me, const game_params *params,
1319                             const char *desc)
1320 {
1321     game_state *state = snew(game_state);
1322     int sz = params->w * params->h;
1323     int i;
1324 
1325     state->cheated = false;
1326     state->completed = false;
1327     state->shared = snew(struct shared_state);
1328     state->shared->refcnt = 1;
1329     state->shared->params = *params; /* struct copy */
1330     state->shared->clues = snewn(sz, int);
1331 
1332     for (i = 0; *desc; ++desc) {
1333 	if (*desc >= 'a' && *desc <= 'z') {
1334 	    int j = *desc - 'a' + 1;
1335 	    assert(i + j <= sz);
1336 	    for (; j; --j) state->shared->clues[i++] = 0;
1337 	} else state->shared->clues[i++] = *desc - '0';
1338     }
1339     state->board = memdup(state->shared->clues, sz, sizeof (int));
1340 
1341     return state;
1342 }
1343 
dup_game(const game_state * state)1344 static game_state *dup_game(const game_state *state)
1345 {
1346     const int sz = state->shared->params.w * state->shared->params.h;
1347     game_state *ret = snew(game_state);
1348 
1349     ret->board = memdup(state->board, sz, sizeof (int));
1350     ret->shared = state->shared;
1351     ret->cheated = state->cheated;
1352     ret->completed = state->completed;
1353     ++ret->shared->refcnt;
1354 
1355     return ret;
1356 }
1357 
free_game(game_state * state)1358 static void free_game(game_state *state)
1359 {
1360     assert(state);
1361     sfree(state->board);
1362     if (--state->shared->refcnt == 0) {
1363         sfree(state->shared->clues);
1364         sfree(state->shared);
1365     }
1366     sfree(state);
1367 }
1368 
solve_game(const game_state * state,const game_state * currstate,const char * aux,const char ** error)1369 static char *solve_game(const game_state *state, const game_state *currstate,
1370                         const char *aux, const char **error)
1371 {
1372     if (aux == NULL) {
1373         const int w = state->shared->params.w;
1374         const int h = state->shared->params.h;
1375 	char *new_aux;
1376         if (!solver(state->board, w, h, &new_aux))
1377             *error = "Sorry, I couldn't find a solution";
1378 	return new_aux;
1379     }
1380     return dupstr(aux);
1381 }
1382 
1383 /*****************************************************************************
1384  * USER INTERFACE STATE AND ACTION                                           *
1385  *****************************************************************************/
1386 
1387 struct game_ui {
1388     bool *sel; /* w*h highlighted squares, or NULL */
1389     int cur_x, cur_y;
1390     bool cur_visible, keydragging;
1391 };
1392 
new_ui(const game_state * state)1393 static game_ui *new_ui(const game_state *state)
1394 {
1395     game_ui *ui = snew(game_ui);
1396 
1397     ui->sel = NULL;
1398     ui->cur_x = ui->cur_y = 0;
1399     ui->cur_visible = false;
1400     ui->keydragging = false;
1401 
1402     return ui;
1403 }
1404 
free_ui(game_ui * ui)1405 static void free_ui(game_ui *ui)
1406 {
1407     if (ui->sel)
1408         sfree(ui->sel);
1409     sfree(ui);
1410 }
1411 
encode_ui(const game_ui * ui)1412 static char *encode_ui(const game_ui *ui)
1413 {
1414     return NULL;
1415 }
1416 
decode_ui(game_ui * ui,const char * encoding)1417 static void decode_ui(game_ui *ui, const char *encoding)
1418 {
1419 }
1420 
game_changed_state(game_ui * ui,const game_state * oldstate,const game_state * newstate)1421 static void game_changed_state(game_ui *ui, const game_state *oldstate,
1422                                const game_state *newstate)
1423 {
1424     /* Clear any selection */
1425     if (ui->sel) {
1426         sfree(ui->sel);
1427         ui->sel = NULL;
1428     }
1429     ui->keydragging = false;
1430 }
1431 
1432 #define PREFERRED_TILE_SIZE 32
1433 #define TILE_SIZE (ds->tilesize)
1434 #define BORDER (TILE_SIZE / 2)
1435 #define BORDER_WIDTH (max(TILE_SIZE / 32, 1))
1436 
1437 struct game_drawstate {
1438     struct game_params params;
1439     int tilesize;
1440     bool started;
1441     int *v, *flags;
1442     int *dsf_scratch, *border_scratch;
1443 };
1444 
interpret_move(const game_state * state,game_ui * ui,const game_drawstate * ds,int x,int y,int button)1445 static char *interpret_move(const game_state *state, game_ui *ui,
1446                             const game_drawstate *ds,
1447                             int x, int y, int button)
1448 {
1449     const int w = state->shared->params.w;
1450     const int h = state->shared->params.h;
1451 
1452     const int tx = (x + TILE_SIZE - BORDER) / TILE_SIZE - 1;
1453     const int ty = (y + TILE_SIZE - BORDER) / TILE_SIZE - 1;
1454 
1455     char *move = NULL;
1456     int i;
1457 
1458     assert(ui);
1459     assert(ds);
1460 
1461     button &= ~MOD_MASK;
1462 
1463     if (button == LEFT_BUTTON || button == LEFT_DRAG) {
1464         /* A left-click anywhere will clear the current selection. */
1465         if (button == LEFT_BUTTON) {
1466             if (ui->sel) {
1467                 sfree(ui->sel);
1468                 ui->sel = NULL;
1469             }
1470         }
1471         if (tx >= 0 && tx < w && ty >= 0 && ty < h) {
1472             if (!ui->sel) {
1473                 ui->sel = snewn(w*h, bool);
1474                 memset(ui->sel, 0, w*h*sizeof(bool));
1475             }
1476             if (!state->shared->clues[w*ty+tx])
1477                 ui->sel[w*ty+tx] = true;
1478         }
1479         ui->cur_visible = false;
1480         return UI_UPDATE;
1481     }
1482 
1483     if (IS_CURSOR_MOVE(button)) {
1484         ui->cur_visible = true;
1485         move_cursor(button, &ui->cur_x, &ui->cur_y, w, h, false);
1486 	if (ui->keydragging) goto select_square;
1487         return UI_UPDATE;
1488     }
1489     if (button == CURSOR_SELECT) {
1490         if (!ui->cur_visible) {
1491             ui->cur_visible = true;
1492             return UI_UPDATE;
1493         }
1494 	ui->keydragging = !ui->keydragging;
1495 	if (!ui->keydragging) return UI_UPDATE;
1496 
1497       select_square:
1498         if (!ui->sel) {
1499             ui->sel = snewn(w*h, bool);
1500             memset(ui->sel, 0, w*h*sizeof(bool));
1501         }
1502 	if (!state->shared->clues[w*ui->cur_y + ui->cur_x])
1503 	    ui->sel[w*ui->cur_y + ui->cur_x] = true;
1504 	return UI_UPDATE;
1505     }
1506     if (button == CURSOR_SELECT2) {
1507 	if (!ui->cur_visible) {
1508 	    ui->cur_visible = true;
1509 	    return UI_UPDATE;
1510 	}
1511         if (!ui->sel) {
1512             ui->sel = snewn(w*h, bool);
1513             memset(ui->sel, 0, w*h*sizeof(bool));
1514         }
1515 	ui->keydragging = false;
1516 	if (!state->shared->clues[w*ui->cur_y + ui->cur_x])
1517 	    ui->sel[w*ui->cur_y + ui->cur_x] ^= 1;
1518 	for (i = 0; i < w*h && !ui->sel[i]; i++);
1519 	if (i == w*h) {
1520 	    sfree(ui->sel);
1521 	    ui->sel = NULL;
1522 	}
1523 	return UI_UPDATE;
1524     }
1525 
1526     if (button == '\b' || button == 27) {
1527 	sfree(ui->sel);
1528 	ui->sel = NULL;
1529 	ui->keydragging = false;
1530 	return UI_UPDATE;
1531     }
1532 
1533     if (button < '0' || button > '9') return NULL;
1534     button -= '0';
1535     if (button > (w == 2 && h == 2 ? 3 : max(w, h))) return NULL;
1536     ui->keydragging = false;
1537 
1538     for (i = 0; i < w*h; i++) {
1539         char buf[32];
1540         if ((ui->sel && ui->sel[i]) ||
1541             (!ui->sel && ui->cur_visible && (w*ui->cur_y+ui->cur_x) == i)) {
1542             if (state->shared->clues[i] != 0) continue; /* in case cursor is on clue */
1543             if (state->board[i] != button) {
1544                 sprintf(buf, "%s%d", move ? "," : "", i);
1545                 if (move) {
1546                     move = srealloc(move, strlen(move)+strlen(buf)+1);
1547                     strcat(move, buf);
1548                 } else {
1549                     move = smalloc(strlen(buf)+1);
1550                     strcpy(move, buf);
1551                 }
1552             }
1553         }
1554     }
1555     if (move) {
1556         char buf[32];
1557         sprintf(buf, "_%d", button);
1558         move = srealloc(move, strlen(move)+strlen(buf)+1);
1559         strcat(move, buf);
1560     }
1561     if (!ui->sel) return move ? move : NULL;
1562     sfree(ui->sel);
1563     ui->sel = NULL;
1564     /* Need to update UI at least, as we cleared the selection */
1565     return move ? move : UI_UPDATE;
1566 }
1567 
execute_move(const game_state * state,const char * move)1568 static game_state *execute_move(const game_state *state, const char *move)
1569 {
1570     game_state *new_state = NULL;
1571     const int sz = state->shared->params.w * state->shared->params.h;
1572 
1573     if (*move == 's') {
1574         int i = 0;
1575         new_state = dup_game(state);
1576         for (++move; i < sz; ++i) new_state->board[i] = move[i] - '0';
1577         new_state->cheated = true;
1578     } else {
1579         int value;
1580         char *endptr, *delim = strchr(move, '_');
1581         if (!delim) goto err;
1582         value = strtol(delim+1, &endptr, 0);
1583         if (*endptr || endptr == delim+1) goto err;
1584         if (value < 0 || value > 9) goto err;
1585         new_state = dup_game(state);
1586         while (*move) {
1587             const int i = strtol(move, &endptr, 0);
1588             if (endptr == move) goto err;
1589             if (i < 0 || i >= sz) goto err;
1590             new_state->board[i] = value;
1591             if (*endptr == '_') break;
1592             if (*endptr != ',') goto err;
1593             move = endptr + 1;
1594         }
1595     }
1596 
1597     /*
1598      * Check for completion.
1599      */
1600     if (!new_state->completed) {
1601         const int w = new_state->shared->params.w;
1602         const int h = new_state->shared->params.h;
1603         const int sz = w * h;
1604         int *dsf = make_dsf(NULL, new_state->board, w, h);
1605         int i;
1606         for (i = 0; i < sz && new_state->board[i] == dsf_size(dsf, i); ++i);
1607         sfree(dsf);
1608         if (i == sz)
1609             new_state->completed = true;
1610     }
1611 
1612     return new_state;
1613 
1614 err:
1615     if (new_state) free_game(new_state);
1616     return NULL;
1617 }
1618 
1619 /* ----------------------------------------------------------------------
1620  * Drawing routines.
1621  */
1622 
1623 #define FLASH_TIME 0.4F
1624 
1625 #define COL_CLUE COL_GRID
1626 enum {
1627     COL_BACKGROUND,
1628     COL_GRID,
1629     COL_HIGHLIGHT,
1630     COL_CORRECT,
1631     COL_ERROR,
1632     COL_USER,
1633     COL_CURSOR,
1634     NCOLOURS
1635 };
1636 
game_compute_size(const game_params * params,int tilesize,int * x,int * y)1637 static void game_compute_size(const game_params *params, int tilesize,
1638                               int *x, int *y)
1639 {
1640     *x = (params->w + 1) * tilesize;
1641     *y = (params->h + 1) * tilesize;
1642 }
1643 
game_set_size(drawing * dr,game_drawstate * ds,const game_params * params,int tilesize)1644 static void game_set_size(drawing *dr, game_drawstate *ds,
1645                           const game_params *params, int tilesize)
1646 {
1647     ds->tilesize = tilesize;
1648 }
1649 
game_colours(frontend * fe,int * ncolours)1650 static float *game_colours(frontend *fe, int *ncolours)
1651 {
1652     float *ret = snewn(3 * NCOLOURS, float);
1653 
1654     frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
1655 
1656     ret[COL_GRID * 3 + 0] = 0.0F;
1657     ret[COL_GRID * 3 + 1] = 0.0F;
1658     ret[COL_GRID * 3 + 2] = 0.0F;
1659 
1660     ret[COL_HIGHLIGHT * 3 + 0] = 0.85F * ret[COL_BACKGROUND * 3 + 0];
1661     ret[COL_HIGHLIGHT * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1];
1662     ret[COL_HIGHLIGHT * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2];
1663 
1664     ret[COL_CORRECT * 3 + 0] = 0.9F * ret[COL_BACKGROUND * 3 + 0];
1665     ret[COL_CORRECT * 3 + 1] = 0.9F * ret[COL_BACKGROUND * 3 + 1];
1666     ret[COL_CORRECT * 3 + 2] = 0.9F * ret[COL_BACKGROUND * 3 + 2];
1667 
1668     ret[COL_CURSOR * 3 + 0] = 0.5F * ret[COL_BACKGROUND * 3 + 0];
1669     ret[COL_CURSOR * 3 + 1] = 0.5F * ret[COL_BACKGROUND * 3 + 1];
1670     ret[COL_CURSOR * 3 + 2] = 0.5F * ret[COL_BACKGROUND * 3 + 2];
1671 
1672     ret[COL_ERROR * 3 + 0] = 1.0F;
1673     ret[COL_ERROR * 3 + 1] = 0.85F * ret[COL_BACKGROUND * 3 + 1];
1674     ret[COL_ERROR * 3 + 2] = 0.85F * ret[COL_BACKGROUND * 3 + 2];
1675 
1676     ret[COL_USER * 3 + 0] = 0.0F;
1677     ret[COL_USER * 3 + 1] = 0.6F * ret[COL_BACKGROUND * 3 + 1];
1678     ret[COL_USER * 3 + 2] = 0.0F;
1679 
1680     *ncolours = NCOLOURS;
1681     return ret;
1682 }
1683 
game_new_drawstate(drawing * dr,const game_state * state)1684 static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
1685 {
1686     struct game_drawstate *ds = snew(struct game_drawstate);
1687     int i;
1688 
1689     ds->tilesize = PREFERRED_TILE_SIZE;
1690     ds->started = false;
1691     ds->params = state->shared->params;
1692     ds->v = snewn(ds->params.w * ds->params.h, int);
1693     ds->flags = snewn(ds->params.w * ds->params.h, int);
1694     for (i = 0; i < ds->params.w * ds->params.h; i++)
1695 	ds->v[i] = ds->flags[i] = -1;
1696     ds->border_scratch = snewn(ds->params.w * ds->params.h, int);
1697     ds->dsf_scratch = NULL;
1698 
1699     return ds;
1700 }
1701 
game_free_drawstate(drawing * dr,game_drawstate * ds)1702 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
1703 {
1704     sfree(ds->v);
1705     sfree(ds->flags);
1706     sfree(ds->border_scratch);
1707     sfree(ds->dsf_scratch);
1708     sfree(ds);
1709 }
1710 
1711 #define BORDER_U   0x001
1712 #define BORDER_D   0x002
1713 #define BORDER_L   0x004
1714 #define BORDER_R   0x008
1715 #define BORDER_UR  0x010
1716 #define BORDER_DR  0x020
1717 #define BORDER_UL  0x040
1718 #define BORDER_DL  0x080
1719 #define HIGH_BG    0x100
1720 #define CORRECT_BG 0x200
1721 #define ERROR_BG   0x400
1722 #define USER_COL   0x800
1723 #define CURSOR_SQ 0x1000
1724 
draw_square(drawing * dr,game_drawstate * ds,int x,int y,int n,int flags)1725 static void draw_square(drawing *dr, game_drawstate *ds, int x, int y,
1726                         int n, int flags)
1727 {
1728     assert(dr);
1729     assert(ds);
1730 
1731     /*
1732      * Clip to the grid square.
1733      */
1734     clip(dr, BORDER + x*TILE_SIZE, BORDER + y*TILE_SIZE,
1735 	 TILE_SIZE, TILE_SIZE);
1736 
1737     /*
1738      * Clear the square.
1739      */
1740     draw_rect(dr,
1741               BORDER + x*TILE_SIZE,
1742               BORDER + y*TILE_SIZE,
1743               TILE_SIZE,
1744               TILE_SIZE,
1745               (flags & HIGH_BG ? COL_HIGHLIGHT :
1746                flags & ERROR_BG ? COL_ERROR :
1747                flags & CORRECT_BG ? COL_CORRECT : COL_BACKGROUND));
1748 
1749     /*
1750      * Draw the grid lines.
1751      */
1752     draw_line(dr, BORDER + x*TILE_SIZE, BORDER + y*TILE_SIZE,
1753 	      BORDER + (x+1)*TILE_SIZE, BORDER + y*TILE_SIZE, COL_GRID);
1754     draw_line(dr, BORDER + x*TILE_SIZE, BORDER + y*TILE_SIZE,
1755 	      BORDER + x*TILE_SIZE, BORDER + (y+1)*TILE_SIZE, COL_GRID);
1756 
1757     /*
1758      * Draw the number.
1759      */
1760     if (n) {
1761         char buf[2];
1762         buf[0] = n + '0';
1763         buf[1] = '\0';
1764         draw_text(dr,
1765                   (x + 1) * TILE_SIZE,
1766                   (y + 1) * TILE_SIZE,
1767                   FONT_VARIABLE,
1768                   TILE_SIZE / 2,
1769                   ALIGN_VCENTRE | ALIGN_HCENTRE,
1770                   flags & USER_COL ? COL_USER : COL_CLUE,
1771                   buf);
1772     }
1773 
1774     /*
1775      * Draw bold lines around the borders.
1776      */
1777     if (flags & BORDER_L)
1778         draw_rect(dr,
1779                   BORDER + x*TILE_SIZE + 1,
1780                   BORDER + y*TILE_SIZE + 1,
1781                   BORDER_WIDTH,
1782                   TILE_SIZE - 1,
1783                   COL_GRID);
1784     if (flags & BORDER_U)
1785         draw_rect(dr,
1786                   BORDER + x*TILE_SIZE + 1,
1787                   BORDER + y*TILE_SIZE + 1,
1788                   TILE_SIZE - 1,
1789                   BORDER_WIDTH,
1790                   COL_GRID);
1791     if (flags & BORDER_R)
1792         draw_rect(dr,
1793                   BORDER + (x+1)*TILE_SIZE - BORDER_WIDTH,
1794                   BORDER + y*TILE_SIZE + 1,
1795                   BORDER_WIDTH,
1796                   TILE_SIZE - 1,
1797                   COL_GRID);
1798     if (flags & BORDER_D)
1799         draw_rect(dr,
1800                   BORDER + x*TILE_SIZE + 1,
1801                   BORDER + (y+1)*TILE_SIZE - BORDER_WIDTH,
1802                   TILE_SIZE - 1,
1803                   BORDER_WIDTH,
1804                   COL_GRID);
1805     if (flags & BORDER_UL)
1806         draw_rect(dr,
1807                   BORDER + x*TILE_SIZE + 1,
1808                   BORDER + y*TILE_SIZE + 1,
1809                   BORDER_WIDTH,
1810                   BORDER_WIDTH,
1811                   COL_GRID);
1812     if (flags & BORDER_UR)
1813         draw_rect(dr,
1814                   BORDER + (x+1)*TILE_SIZE - BORDER_WIDTH,
1815                   BORDER + y*TILE_SIZE + 1,
1816                   BORDER_WIDTH,
1817                   BORDER_WIDTH,
1818                   COL_GRID);
1819     if (flags & BORDER_DL)
1820         draw_rect(dr,
1821                   BORDER + x*TILE_SIZE + 1,
1822                   BORDER + (y+1)*TILE_SIZE - BORDER_WIDTH,
1823                   BORDER_WIDTH,
1824                   BORDER_WIDTH,
1825                   COL_GRID);
1826     if (flags & BORDER_DR)
1827         draw_rect(dr,
1828                   BORDER + (x+1)*TILE_SIZE - BORDER_WIDTH,
1829                   BORDER + (y+1)*TILE_SIZE - BORDER_WIDTH,
1830                   BORDER_WIDTH,
1831                   BORDER_WIDTH,
1832                   COL_GRID);
1833 
1834     if (flags & CURSOR_SQ) {
1835         int coff = TILE_SIZE/8;
1836         draw_rect_outline(dr,
1837                           BORDER + x*TILE_SIZE + coff,
1838                           BORDER + y*TILE_SIZE + coff,
1839                           TILE_SIZE - coff*2,
1840                           TILE_SIZE - coff*2,
1841                           COL_CURSOR);
1842     }
1843 
1844     unclip(dr);
1845 
1846     draw_update(dr,
1847 		BORDER + x*TILE_SIZE,
1848 		BORDER + y*TILE_SIZE,
1849 		TILE_SIZE,
1850 		TILE_SIZE);
1851 }
1852 
draw_grid(drawing * dr,game_drawstate * ds,const game_state * state,const game_ui * ui,bool flashy,bool borders,bool shading)1853 static void draw_grid(
1854     drawing *dr, game_drawstate *ds, const game_state *state,
1855     const game_ui *ui, bool flashy, bool borders, bool shading)
1856 {
1857     const int w = state->shared->params.w;
1858     const int h = state->shared->params.h;
1859     int x;
1860     int y;
1861 
1862     /*
1863      * Build a dsf for the board in its current state, to use for
1864      * highlights and hints.
1865      */
1866     ds->dsf_scratch = make_dsf(ds->dsf_scratch, state->board, w, h);
1867 
1868     /*
1869      * Work out where we're putting borders between the cells.
1870      */
1871     for (y = 0; y < w*h; y++)
1872 	ds->border_scratch[y] = 0;
1873 
1874     for (y = 0; y < h; y++)
1875         for (x = 0; x < w; x++) {
1876             int dx, dy;
1877             int v1, s1, v2, s2;
1878 
1879             for (dx = 0; dx <= 1; dx++) {
1880                 bool border = false;
1881 
1882                 dy = 1 - dx;
1883 
1884                 if (x+dx >= w || y+dy >= h)
1885                     continue;
1886 
1887                 v1 = state->board[y*w+x];
1888                 v2 = state->board[(y+dy)*w+(x+dx)];
1889                 s1 = dsf_size(ds->dsf_scratch, y*w+x);
1890                 s2 = dsf_size(ds->dsf_scratch, (y+dy)*w+(x+dx));
1891 
1892                 /*
1893                  * We only ever draw a border between two cells if
1894                  * they don't have the same contents.
1895                  */
1896                 if (v1 != v2) {
1897                     /*
1898                      * But in that situation, we don't always draw
1899                      * a border. We do if the two cells both
1900                      * contain actual numbers...
1901                      */
1902                     if (v1 && v2)
1903                         border = true;
1904 
1905                     /*
1906                      * ... or if at least one of them is a
1907                      * completed or overfull omino.
1908                      */
1909                     if (v1 && s1 >= v1)
1910                         border = true;
1911                     if (v2 && s2 >= v2)
1912                         border = true;
1913                 }
1914 
1915                 if (border)
1916                     ds->border_scratch[y*w+x] |= (dx ? 1 : 2);
1917             }
1918         }
1919 
1920     /*
1921      * Actually do the drawing.
1922      */
1923     for (y = 0; y < h; ++y)
1924         for (x = 0; x < w; ++x) {
1925             /*
1926              * Determine what we need to draw in this square.
1927              */
1928             int i = y*w+x, v = state->board[i];
1929             int flags = 0;
1930 
1931             if (flashy || !shading) {
1932                 /* clear all background flags */
1933             } else if (ui && ui->sel && ui->sel[i]) {
1934                 flags |= HIGH_BG;
1935             } else if (v) {
1936                 int size = dsf_size(ds->dsf_scratch, i);
1937                 if (size == v)
1938                     flags |= CORRECT_BG;
1939                 else if (size > v)
1940                     flags |= ERROR_BG;
1941 		else {
1942 		    int rt = dsf_canonify(ds->dsf_scratch, i), j;
1943 		    for (j = 0; j < w*h; ++j) {
1944 			int k;
1945 			if (dsf_canonify(ds->dsf_scratch, j) != rt) continue;
1946 			for (k = 0; k < 4; ++k) {
1947 			    const int xx = j % w + dx[k], yy = j / w + dy[k];
1948 			    if (xx >= 0 && xx < w && yy >= 0 && yy < h &&
1949 				state->board[yy*w + xx] == EMPTY)
1950 				goto noflag;
1951 			}
1952 		    }
1953 		    flags |= ERROR_BG;
1954 		  noflag:
1955 		    ;
1956 		}
1957             }
1958             if (ui && ui->cur_visible && x == ui->cur_x && y == ui->cur_y)
1959               flags |= CURSOR_SQ;
1960 
1961             /*
1962              * Borders at the very edges of the grid are
1963              * independent of the `borders' flag.
1964              */
1965             if (x == 0)
1966                 flags |= BORDER_L;
1967             if (y == 0)
1968                 flags |= BORDER_U;
1969             if (x == w-1)
1970                 flags |= BORDER_R;
1971             if (y == h-1)
1972                 flags |= BORDER_D;
1973 
1974             if (borders) {
1975                 if (x == 0 || (ds->border_scratch[y*w+(x-1)] & 1))
1976                     flags |= BORDER_L;
1977                 if (y == 0 || (ds->border_scratch[(y-1)*w+x] & 2))
1978                     flags |= BORDER_U;
1979                 if (x == w-1 || (ds->border_scratch[y*w+x] & 1))
1980                     flags |= BORDER_R;
1981                 if (y == h-1 || (ds->border_scratch[y*w+x] & 2))
1982                     flags |= BORDER_D;
1983 
1984                 if (y > 0 && x > 0 && (ds->border_scratch[(y-1)*w+(x-1)]))
1985                     flags |= BORDER_UL;
1986                 if (y > 0 && x < w-1 &&
1987                     ((ds->border_scratch[(y-1)*w+x] & 1) ||
1988                      (ds->border_scratch[(y-1)*w+(x+1)] & 2)))
1989                     flags |= BORDER_UR;
1990                 if (y < h-1 && x > 0 &&
1991                     ((ds->border_scratch[y*w+(x-1)] & 2) ||
1992                      (ds->border_scratch[(y+1)*w+(x-1)] & 1)))
1993                     flags |= BORDER_DL;
1994                 if (y < h-1 && x < w-1 &&
1995                     ((ds->border_scratch[y*w+(x+1)] & 2) ||
1996                      (ds->border_scratch[(y+1)*w+x] & 1)))
1997                     flags |= BORDER_DR;
1998             }
1999 
2000             if (!state->shared->clues[y*w+x])
2001                 flags |= USER_COL;
2002 
2003             if (ds->v[y*w+x] != v || ds->flags[y*w+x] != flags) {
2004                 draw_square(dr, ds, x, y, v, flags);
2005                 ds->v[y*w+x] = v;
2006                 ds->flags[y*w+x] = flags;
2007             }
2008         }
2009 }
2010 
game_redraw(drawing * dr,game_drawstate * ds,const game_state * oldstate,const game_state * state,int dir,const game_ui * ui,float animtime,float flashtime)2011 static void game_redraw(drawing *dr, game_drawstate *ds,
2012                         const game_state *oldstate, const game_state *state,
2013                         int dir, const game_ui *ui,
2014                         float animtime, float flashtime)
2015 {
2016     const int w = state->shared->params.w;
2017     const int h = state->shared->params.h;
2018 
2019     const bool flashy =
2020         flashtime > 0 &&
2021         (flashtime <= FLASH_TIME/3 || flashtime >= FLASH_TIME*2/3);
2022 
2023     if (!ds->started) {
2024 	/*
2025 	 * Black rectangle which is the main grid.
2026 	 */
2027 	draw_rect(dr, BORDER - BORDER_WIDTH, BORDER - BORDER_WIDTH,
2028 		  w*TILE_SIZE + 2*BORDER_WIDTH + 1,
2029 		  h*TILE_SIZE + 2*BORDER_WIDTH + 1,
2030 		  COL_GRID);
2031 
2032         draw_update(dr, 0, 0, w*TILE_SIZE + 2*BORDER, h*TILE_SIZE + 2*BORDER);
2033 
2034         ds->started = true;
2035     }
2036 
2037     draw_grid(dr, ds, state, ui, flashy, true, true);
2038 }
2039 
game_anim_length(const game_state * oldstate,const game_state * newstate,int dir,game_ui * ui)2040 static float game_anim_length(const game_state *oldstate,
2041                               const game_state *newstate, int dir, game_ui *ui)
2042 {
2043     return 0.0F;
2044 }
2045 
game_flash_length(const game_state * oldstate,const game_state * newstate,int dir,game_ui * ui)2046 static float game_flash_length(const game_state *oldstate,
2047                                const game_state *newstate, int dir, game_ui *ui)
2048 {
2049     assert(oldstate);
2050     assert(newstate);
2051     assert(newstate->shared);
2052     assert(oldstate->shared == newstate->shared);
2053     if (!oldstate->completed && newstate->completed &&
2054 	!oldstate->cheated && !newstate->cheated)
2055         return FLASH_TIME;
2056     return 0.0F;
2057 }
2058 
game_get_cursor_location(const game_ui * ui,const game_drawstate * ds,const game_state * state,const game_params * params,int * x,int * y,int * w,int * h)2059 static void game_get_cursor_location(const game_ui *ui,
2060                                      const game_drawstate *ds,
2061                                      const game_state *state,
2062                                      const game_params *params,
2063                                      int *x, int *y, int *w, int *h)
2064 {
2065     if(ui->cur_visible)
2066     {
2067 	*x = BORDER + ui->cur_x * TILE_SIZE;
2068 	*y = BORDER + ui->cur_y * TILE_SIZE;
2069 	*w = *h = TILE_SIZE;
2070     }
2071 }
2072 
game_status(const game_state * state)2073 static int game_status(const game_state *state)
2074 {
2075     return state->completed ? +1 : 0;
2076 }
2077 
game_timing_state(const game_state * state,game_ui * ui)2078 static bool game_timing_state(const game_state *state, game_ui *ui)
2079 {
2080     return true;
2081 }
2082 
game_print_size(const game_params * params,float * x,float * y)2083 static void game_print_size(const game_params *params, float *x, float *y)
2084 {
2085     int pw, ph;
2086 
2087     /*
2088      * I'll use 6mm squares by default.
2089      */
2090     game_compute_size(params, 600, &pw, &ph);
2091     *x = pw / 100.0F;
2092     *y = ph / 100.0F;
2093 }
2094 
game_print(drawing * dr,const game_state * state,int tilesize)2095 static void game_print(drawing *dr, const game_state *state, int tilesize)
2096 {
2097     const int w = state->shared->params.w;
2098     const int h = state->shared->params.h;
2099     int c, i;
2100     bool borders;
2101 
2102     /* Ick: fake up `ds->tilesize' for macro expansion purposes */
2103     game_drawstate *ds = game_new_drawstate(dr, state);
2104     game_set_size(dr, ds, NULL, tilesize);
2105 
2106     c = print_mono_colour(dr, 1); assert(c == COL_BACKGROUND);
2107     c = print_mono_colour(dr, 0); assert(c == COL_GRID);
2108     c = print_mono_colour(dr, 1); assert(c == COL_HIGHLIGHT);
2109     c = print_mono_colour(dr, 1); assert(c == COL_CORRECT);
2110     c = print_mono_colour(dr, 1); assert(c == COL_ERROR);
2111     c = print_mono_colour(dr, 0); assert(c == COL_USER);
2112 
2113     /*
2114      * Border.
2115      */
2116     draw_rect(dr, BORDER - BORDER_WIDTH, BORDER - BORDER_WIDTH,
2117               w*TILE_SIZE + 2*BORDER_WIDTH + 1,
2118               h*TILE_SIZE + 2*BORDER_WIDTH + 1,
2119               COL_GRID);
2120 
2121     /*
2122      * We'll draw borders between the ominoes iff the grid is not
2123      * pristine. So scan it to see if it is.
2124      */
2125     borders = false;
2126     for (i = 0; i < w*h; i++)
2127         if (state->board[i] && !state->shared->clues[i])
2128             borders = true;
2129 
2130     /*
2131      * Draw grid.
2132      */
2133     print_line_width(dr, TILE_SIZE / 64);
2134     draw_grid(dr, ds, state, NULL, false, borders, false);
2135 
2136     /*
2137      * Clean up.
2138      */
2139     game_free_drawstate(dr, ds);
2140 }
2141 
2142 #ifdef COMBINED
2143 #define thegame filling
2144 #endif
2145 
2146 const struct game thegame = {
2147     "Filling", "games.filling", "filling",
2148     default_params,
2149     game_fetch_preset, NULL,
2150     decode_params,
2151     encode_params,
2152     free_params,
2153     dup_params,
2154     true, game_configure, custom_params,
2155     validate_params,
2156     new_game_desc,
2157     validate_desc,
2158     new_game,
2159     dup_game,
2160     free_game,
2161     true, solve_game,
2162     true, game_can_format_as_text_now, game_text_format,
2163     new_ui,
2164     free_ui,
2165     encode_ui,
2166     decode_ui,
2167     game_request_keys,
2168     game_changed_state,
2169     interpret_move,
2170     execute_move,
2171     PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
2172     game_colours,
2173     game_new_drawstate,
2174     game_free_drawstate,
2175     game_redraw,
2176     game_anim_length,
2177     game_flash_length,
2178     game_get_cursor_location,
2179     game_status,
2180     true, false, game_print_size, game_print,
2181     false,				   /* wants_statusbar */
2182     false, game_timing_state,
2183     REQUIRE_NUMPAD,		       /* flags */
2184 };
2185 
2186 #ifdef STANDALONE_SOLVER /* solver? hah! */
2187 
main(int argc,char ** argv)2188 int main(int argc, char **argv) {
2189     while (*++argv) {
2190         game_params *params;
2191         game_state *state;
2192         char *par;
2193         char *desc;
2194 
2195         for (par = desc = *argv; *desc != '\0' && *desc != ':'; ++desc);
2196         if (*desc == '\0') {
2197             fprintf(stderr, "bad puzzle id: %s", par);
2198             continue;
2199         }
2200 
2201         *desc++ = '\0';
2202 
2203         params = snew(game_params);
2204         decode_params(params, par);
2205         state = new_game(NULL, params, desc);
2206         if (solver(state->board, params->w, params->h, NULL))
2207             printf("%s:%s: solvable\n", par, desc);
2208         else
2209             printf("%s:%s: not solvable\n", par, desc);
2210     }
2211     return 0;
2212 }
2213 
2214 #endif
2215 
2216 /* vim: set shiftwidth=4 tabstop=8: */
2217