--- /dev/null
+/*
+ * loopy.c: An implementation of the Nikoli game 'Loop the loop'.
+ * (c) Mike Pinna, 2005
+ *
+ * vim: set shiftwidth=4 :set textwidth=80:
+ */
+
+/*
+ * TODO:
+ *
+ * - setting very high recursion depth seems to cause memory
+ * munching: are we recursing before checking completion, by any
+ * chance?
+ *
+ * - there's an interesting deductive technique which makes use of
+ * topology rather than just graph theory. Each _square_ in the
+ * grid is either inside or outside the loop; you can tell that
+ * two squares are on the same side of the loop if they're
+ * separated by an x (or, more generally, by a path crossing no
+ * LINE_UNKNOWNs and an even number of LINE_YESes), and on the
+ * opposite side of the loop if they're separated by a line (or
+ * an odd number of LINE_YESes and no LINE_UNKNOWNs). Oh, and
+ * any square separated from the outside of the grid by a
+ * LINE_YES or a LINE_NO is on the inside or outside
+ * respectively. So if you can track this for all squares, you
+ * can occasionally spot that two squares are separated by a
+ * LINE_UNKNOWN but their relative insideness is known, and
+ * therefore deduce the state of the edge between them.
+ * + An efficient way to track this would be by augmenting the
+ * disjoint set forest data structure. Each element, along
+ * with a pointer to a parent member of its equivalence
+ * class, would also carry a one-bit field indicating whether
+ * it was equal or opposite to its parent. Then you could
+ * keep flipping a bit as you ascended the tree during
+ * dsf_canonify(), and hence you'd be able to return the
+ * relationship of the input value to its ultimate parent
+ * (and also you could then get all those bits right when you
+ * went back up the tree rewriting). So you'd be able to
+ * query whether any two elements were known-equal,
+ * known-opposite, or not-known, and you could add new
+ * equalities or oppositenesses to increase your knowledge.
+ * (Of course the algorithm would have to fail an assertion
+ * if you tried to tell it two things it already knew to be
+ * opposite were equal, or vice versa!)
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+#include <math.h>
+
+#include "puzzles.h"
+#include "tree234.h"
+
+#define PREFERRED_TILE_SIZE 32
+#define TILE_SIZE (ds->tilesize)
+#define LINEWIDTH TILE_SIZE / 16
+#define BORDER (TILE_SIZE / 2)
+
+#define FLASH_TIME 0.4F
+
+#define HL_COUNT(state) ((state)->w * ((state)->h + 1))
+#define VL_COUNT(state) (((state)->w + 1) * (state)->h)
+#define DOT_COUNT(state) (((state)->w + 1) * ((state)->h + 1))
+#define SQUARE_COUNT(state) ((state)->w * (state)->h)
+
+#define ABOVE_SQUARE(state, i, j) ((state)->hl[(i) + (state)->w * (j)])
+#define BELOW_SQUARE(state, i, j) ABOVE_SQUARE(state, i, (j)+1)
+
+#define LEFTOF_SQUARE(state, i, j) ((state)->vl[(i) + ((state)->w + 1) * (j)])
+#define RIGHTOF_SQUARE(state, i, j) LEFTOF_SQUARE(state, (i)+1, j)
+
+#define LEGAL_DOT(state, i, j) ((i) >= 0 && (j) >= 0 && \
+ (i) <= (state)->w && (j) <= (state)->h)
+
+/*
+ * These macros return rvalues only, but can cope with being passed
+ * out-of-range coordinates.
+ */
+#define ABOVE_DOT(state, i, j) ((!LEGAL_DOT(state, i, j) || j <= 0) ? \
+ LINE_NO : LV_ABOVE_DOT(state, i, j))
+#define BELOW_DOT(state, i, j) ((!LEGAL_DOT(state, i, j) || j >= (state)->h) ? \
+ LINE_NO : LV_BELOW_DOT(state, i, j))
+
+#define LEFTOF_DOT(state, i, j) ((!LEGAL_DOT(state, i, j) || i <= 0) ? \
+ LINE_NO : LV_LEFTOF_DOT(state, i, j))
+#define RIGHTOF_DOT(state, i, j) ((!LEGAL_DOT(state, i, j) || i >= (state)->w)?\
+ LINE_NO : LV_RIGHTOF_DOT(state, i, j))
+
+/*
+ * These macros expect to be passed valid coordinates, and return
+ * lvalues.
+ */
+#define LV_BELOW_DOT(state, i, j) ((state)->vl[(i) + ((state)->w + 1) * (j)])
+#define LV_ABOVE_DOT(state, i, j) LV_BELOW_DOT(state, i, (j)-1)
+
+#define LV_RIGHTOF_DOT(state, i, j) ((state)->hl[(i) + (state)->w * (j)])
+#define LV_LEFTOF_DOT(state, i, j) LV_RIGHTOF_DOT(state, (i)-1, j)
+
+#define CLUE_AT(state, i, j) ((i < 0 || i >= (state)->w || \
+ j < 0 || j >= (state)->h) ? \
+ ' ' : LV_CLUE_AT(state, i, j))
+
+#define LV_CLUE_AT(state, i, j) ((state)->clues[(i) + (state)->w * (j)])
+
+#define OPP(dir) (dir == LINE_UNKNOWN ? LINE_UNKNOWN : \
+ dir == LINE_YES ? LINE_NO : LINE_YES)
+
+static char *game_text_format(game_state *state);
+
+enum {
+ COL_BACKGROUND,
+ COL_FOREGROUND,
+ COL_HIGHLIGHT,
+ NCOLOURS
+};
+
+enum line_state { LINE_UNKNOWN, LINE_YES, LINE_NO };
+
+enum direction { UP, DOWN, LEFT, RIGHT };
+
+struct game_params {
+ int w, h, rec;
+};
+
+struct game_state {
+ int w, h;
+
+ /* Put ' ' in a square that doesn't get a clue */
+ char *clues;
+
+ /* Arrays of line states, stored left-to-right, top-to-bottom */
+ char *hl, *vl;
+
+ int solved;
+ int cheated;
+
+ int recursion_depth;
+};
+
+static game_state *dup_game(game_state *state)
+{
+ game_state *ret = snew(game_state);
+
+ ret->h = state->h;
+ ret->w = state->w;
+ ret->solved = state->solved;
+ ret->cheated = state->cheated;
+
+ ret->clues = snewn(SQUARE_COUNT(state), char);
+ memcpy(ret->clues, state->clues, SQUARE_COUNT(state));
+
+ ret->hl = snewn(HL_COUNT(state), char);
+ memcpy(ret->hl, state->hl, HL_COUNT(state));
+
+ ret->vl = snewn(VL_COUNT(state), char);
+ memcpy(ret->vl, state->vl, VL_COUNT(state));
+
+ ret->recursion_depth = state->recursion_depth;
+
+ return ret;
+}
+
+static void free_game(game_state *state)
+{
+ if (state) {
+ sfree(state->clues);
+ sfree(state->hl);
+ sfree(state->vl);
+ sfree(state);
+ }
+}
+
+enum solver_status {
+ SOLVER_SOLVED, /* This is the only solution the solver could find */
+ SOLVER_MISTAKE, /* This is definitely not a solution */
+ SOLVER_AMBIGUOUS, /* This _might_ be an ambiguous solution */
+ SOLVER_INCOMPLETE /* This may be a partial solution */
+};
+
+typedef struct solver_state {
+ game_state *state;
+ /* XXX dot_atleastone[i,j, dline] is equivalent to */
+ /* dot_atmostone[i,j,OPP_DLINE(dline)] */
+ char *dot_atleastone;
+ char *dot_atmostone;
+/* char *dline_identical; */
+ int recursion_remaining;
+ enum solver_status solver_status;
+ int *dotdsf, *looplen;
+} solver_state;
+
+static solver_state *new_solver_state(game_state *state) {
+ solver_state *ret = snew(solver_state);
+ int i;
+
+ ret->state = dup_game(state);
+
+ ret->dot_atmostone = snewn(DOT_COUNT(state), char);
+ memset(ret->dot_atmostone, 0, DOT_COUNT(state));
+ ret->dot_atleastone = snewn(DOT_COUNT(state), char);
+ memset(ret->dot_atleastone, 0, DOT_COUNT(state));
+
+#if 0
+ dline_identical = snewn(DOT_COUNT(state), char);
+ memset(dline_identical, 0, DOT_COUNT(state));
+#endif
+
+ ret->recursion_remaining = state->recursion_depth;
+ ret->solver_status = SOLVER_INCOMPLETE; /* XXX This may be a lie */
+
+ ret->dotdsf = snewn(DOT_COUNT(state), int);
+ ret->looplen = snewn(DOT_COUNT(state), int);
+ for (i = 0; i < DOT_COUNT(state); i++) {
+ ret->dotdsf[i] = i;
+ ret->looplen[i] = 1;
+ }
+
+ return ret;
+}
+
+static void free_solver_state(solver_state *sstate) {
+ if (sstate) {
+ free_game(sstate->state);
+ sfree(sstate->dot_atleastone);
+ sfree(sstate->dot_atmostone);
+ /* sfree(sstate->dline_identical); */
+ }
+}
+
+static solver_state *dup_solver_state(solver_state *sstate) {
+ game_state *state = dup_game(sstate->state);
+
+ solver_state *ret = snew(solver_state);
+
+ ret->state = dup_game(state);
+
+ ret->dot_atmostone = snewn(DOT_COUNT(state), char);
+ memcpy(ret->dot_atmostone, sstate->dot_atmostone, DOT_COUNT(state));
+
+ ret->dot_atleastone = snewn(DOT_COUNT(state), char);
+ memcpy(ret->dot_atleastone, sstate->dot_atleastone, DOT_COUNT(state));
+
+#if 0
+ ret->dline_identical = snewn((state->w + 1) * (state->h + 1), char);
+ memcpy(ret->dline_identical, state->dot_atmostone,
+ (state->w + 1) * (state->h + 1));
+#endif
+
+ ret->recursion_remaining = sstate->recursion_remaining;
+ ret->solver_status = sstate->solver_status;
+
+ ret->dotdsf = snewn(DOT_COUNT(state), int);
+ ret->looplen = snewn(DOT_COUNT(state), int);
+ memcpy(ret->dotdsf, sstate->dotdsf, DOT_COUNT(state) * sizeof(int));
+ memcpy(ret->looplen, sstate->looplen, DOT_COUNT(state) * sizeof(int));
+
+ return ret;
+}
+
+/*
+ * Merge two dots due to the existence of an edge between them.
+ * Updates the dsf tracking equivalence classes, and keeps track of
+ * the length of path each dot is currently a part of.
+ */
+static void merge_dots(solver_state *sstate, int x1, int y1, int x2, int y2)
+{
+ int i, j, len;
+
+ i = y1 * (sstate->state->w + 1) + x1;
+ j = y2 * (sstate->state->w + 1) + x2;
+
+ i = dsf_canonify(sstate->dotdsf, i);
+ j = dsf_canonify(sstate->dotdsf, j);
+
+ if (i != j) {
+ len = sstate->looplen[i] + sstate->looplen[j];
+ dsf_merge(sstate->dotdsf, i, j);
+ i = dsf_canonify(sstate->dotdsf, i);
+ sstate->looplen[i] = len;
+ }
+}
+
+/* Count the number of lines of a particular type currently going into the
+ * given dot. Lines going off the edge of the board are assumed fixed no. */
+static int dot_order(const game_state* state, int i, int j, char line_type)
+{
+ int n = 0;
+
+ if (i > 0) {
+ if (LEFTOF_DOT(state, i, j) == line_type)
+ ++n;
+ } else {
+ if (line_type == LINE_NO)
+ ++n;
+ }
+ if (i < state->w) {
+ if (RIGHTOF_DOT(state, i, j) == line_type)
+ ++n;
+ } else {
+ if (line_type == LINE_NO)
+ ++n;
+ }
+ if (j > 0) {
+ if (ABOVE_DOT(state, i, j) == line_type)
+ ++n;
+ } else {
+ if (line_type == LINE_NO)
+ ++n;
+ }
+ if (j < state->h) {
+ if (BELOW_DOT(state, i, j) == line_type)
+ ++n;
+ } else {
+ if (line_type == LINE_NO)
+ ++n;
+ }
+
+ return n;
+}
+/* Count the number of lines of a particular type currently surrounding the
+ * given square */
+static int square_order(const game_state* state, int i, int j, char line_type)
+{
+ int n = 0;
+
+ if (ABOVE_SQUARE(state, i, j) == line_type)
+ ++n;
+ if (BELOW_SQUARE(state, i, j) == line_type)
+ ++n;
+ if (LEFTOF_SQUARE(state, i, j) == line_type)
+ ++n;
+ if (RIGHTOF_SQUARE(state, i, j) == line_type)
+ ++n;
+
+ return n;
+}
+
+/* Set all lines bordering a dot of type old_type to type new_type */
+static void dot_setall(game_state *state, int i, int j,
+ char old_type, char new_type)
+{
+/* printf("dot_setall([%d,%d], %d, %d)\n", i, j, old_type, new_type); */
+ if (i > 0 && LEFTOF_DOT(state, i, j) == old_type)
+ LV_LEFTOF_DOT(state, i, j) = new_type;
+ if (i < state->w && RIGHTOF_DOT(state, i, j) == old_type)
+ LV_RIGHTOF_DOT(state, i, j) = new_type;
+ if (j > 0 && ABOVE_DOT(state, i, j) == old_type)
+ LV_ABOVE_DOT(state, i, j) = new_type;
+ if (j < state->h && BELOW_DOT(state, i, j) == old_type)
+ LV_BELOW_DOT(state, i, j) = new_type;
+}
+/* Set all lines bordering a square of type old_type to type new_type */
+static void square_setall(game_state *state, int i, int j,
+ char old_type, char new_type)
+{
+ if (ABOVE_SQUARE(state, i, j) == old_type)
+ ABOVE_SQUARE(state, i, j) = new_type;
+ if (BELOW_SQUARE(state, i, j) == old_type)
+ BELOW_SQUARE(state, i, j) = new_type;
+ if (LEFTOF_SQUARE(state, i, j) == old_type)
+ LEFTOF_SQUARE(state, i, j) = new_type;
+ if (RIGHTOF_SQUARE(state, i, j) == old_type)
+ RIGHTOF_SQUARE(state, i, j) = new_type;
+}
+
+static game_params *default_params(void)
+{
+ game_params *ret = snew(game_params);
+
+ ret->h = 10;
+ ret->w = 10;
+ ret->rec = 0;
+
+ return ret;
+}
+
+static game_params *dup_params(game_params *params)
+{
+ game_params *ret = snew(game_params);
+ *ret = *params; /* structure copy */
+ return ret;
+}
+
+static const struct {
+ char *desc;
+ game_params params;
+} loopy_presets[] = {
+ { "4x4 Easy", { 4, 4, 0 } },
+ { "4x4 Hard", { 4, 4, 2 } },
+ { "7x7 Easy", { 7, 7, 0 } },
+ { "7x7 Hard", { 7, 7, 0 } },
+ { "10x10 Easy", { 10, 10, 0 } },
+ { "10x10 Hard", { 10, 10, 2 } },
+ { "15x15 Easy", { 15, 15, 0 } },
+ { "20x30 Easy", { 20, 30, 0 } }
+};
+
+static int game_fetch_preset(int i, char **name, game_params **params)
+{
+ game_params tmppar;
+
+ if (i < 0 || i >= lenof(loopy_presets))
+ return FALSE;
+
+ tmppar = loopy_presets[i].params;
+ *params = dup_params(&tmppar);
+ *name = dupstr(loopy_presets[i].desc);
+
+ return TRUE;
+}
+
+static void free_params(game_params *params)
+{
+ sfree(params);
+}
+
+static void decode_params(game_params *params, char const *string)
+{
+ params->h = params->w = atoi(string);
+ params->rec = 0;
+ while (*string && isdigit((unsigned char)*string)) string++;
+ if (*string == 'x') {
+ string++;
+ params->h = atoi(string);
+ while (*string && isdigit((unsigned char)*string)) string++;
+ }
+ if (*string == 'r') {
+ string++;
+ params->rec = atoi(string);
+ while (*string && isdigit((unsigned char)*string)) string++;
+ }
+}
+
+static char *encode_params(game_params *params, int full)
+{
+ char str[80];
+ sprintf(str, "%dx%d", params->w, params->h);
+ if (full)
+ sprintf(str + strlen(str), "r%d", params->rec);
+ return dupstr(str);
+}
+
+static config_item *game_configure(game_params *params)
+{
+ config_item *ret;
+ char buf[80];
+
+ ret = snewn(4, 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 = "Recursion depth";
+ ret[2].type = C_STRING;
+ sprintf(buf, "%d", params->rec);
+ ret[2].sval = dupstr(buf);
+ ret[2].ival = 0;
+
+ ret[3].name = NULL;
+ ret[3].type = C_END;
+ ret[3].sval = NULL;
+ ret[3].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->rec = atoi(cfg[2].sval);
+
+ return ret;
+}
+
+static char *validate_params(game_params *params, int full)
+{
+ if (params->w < 4 || params->h < 4)
+ return "Width and height must both be at least 4";
+ if (params->rec < 0)
+ return "Recursion depth can't be negative";
+ return NULL;
+}
+
+/* We're going to store a list of current candidate squares for lighting.
+ * Each square gets a 'score', which tells us how adding that square right
+ * now would affect the length of the solution loop. We're trying to
+ * maximise that quantity so will bias our random selection of squares to
+ * light towards those with high scores */
+struct square {
+ int score;
+ int random;
+ int x, y;
+};
+
+static int get_square_cmpfn(void *v1, void *v2)
+{
+ struct square *s1 = (struct square *)v1;
+ struct square *s2 = (struct square *)v2;
+ int r;
+
+ r = s1->x - s2->x;
+ if (r)
+ return r;
+
+ r = s1->y - s2->y;
+ if (r)
+ return r;
+
+ return 0;
+}
+
+static int square_sort_cmpfn(void *v1, void *v2)
+{
+ struct square *s1 = (struct square *)v1;
+ struct square *s2 = (struct square *)v2;
+ int r;
+
+ r = s2->score - s1->score;
+ if (r) {
+ return r;
+ }
+
+ r = s1->random - s2->random;
+ if (r) {
+ return r;
+ }
+
+ /*
+ * It's _just_ possible that two squares might have been given
+ * the same random value. In that situation, fall back to
+ * comparing based on the coordinates. This introduces a tiny
+ * directional bias, but not a significant one.
+ */
+ return get_square_cmpfn(v1, v2);
+}
+
+static void print_tree(tree234 *tree)
+{
+#if 0
+ int i = 0;
+ struct square *s;
+ printf("Print tree:\n");
+ while (i < count234(tree)) {
+ s = (struct square *)index234(tree, i);
+ assert(s);
+ printf(" [%d,%d], %d, %d\n", s->x, s->y, s->score, s->random);
+ ++i;
+ }
+#endif
+}
+
+enum { SQUARE_LIT, SQUARE_UNLIT };
+
+#define SQUARE_STATE(i, j) \
+ (((i) < 0 || (i) >= params->w || \
+ (j) < 0 || (j) >= params->h) ? \
+ SQUARE_UNLIT : LV_SQUARE_STATE(i,j))
+
+#define LV_SQUARE_STATE(i, j) board[(i) + params->w * (j)]
+
+static void print_board(const game_params *params, const char *board)
+{
+#if 0
+ int i,j;
+
+ printf(" ");
+ for (i = 0; i < params->w; i++) {
+ printf("%d", i%10);
+ }
+ printf("\n");
+ for (j = 0; j < params->h; j++) {
+ printf("%d", j%10);
+ for (i = 0; i < params->w; i++) {
+ printf("%c", SQUARE_STATE(i, j) ? ' ' : 'O');
+ }
+ printf("\n");
+ }
+#endif
+}
+
+static char *new_fullyclued_board(game_params *params, random_state *rs)
+{
+ char *clues;
+ char *board;
+ int i, j, a, b, c;
+ game_state s;
+ game_state *state = &s;
+ int board_area = SQUARE_COUNT(params);
+ int t;
+
+ struct square *square, *tmpsquare, *sq;
+ struct square square_pos;
+
+ /* These will contain exactly the same information, sorted into different
+ * orders */
+ tree234 *lightable_squares_sorted, *lightable_squares_gettable;
+
+#define SQUARE_REACHABLE(i,j) \
+ (t = (SQUARE_STATE(i-1, j) == SQUARE_LIT || \
+ SQUARE_STATE(i+1, j) == SQUARE_LIT || \
+ SQUARE_STATE(i, j-1) == SQUARE_LIT || \
+ SQUARE_STATE(i, j+1) == SQUARE_LIT), \
+/* printf("SQUARE_REACHABLE(%d,%d) = %d\n", i, j, t), */ \
+ t)
+
+
+ /* One situation in which we may not light a square is if that'll leave one
+ * square above/below and one left/right of us unlit, separated by a lit
+ * square diagnonal from us */
+#define SQUARE_DIAGONAL_VIOLATION(i, j, h, v) \
+ (t = (SQUARE_STATE((i)+(h), (j)) == SQUARE_UNLIT && \
+ SQUARE_STATE((i), (j)+(v)) == SQUARE_UNLIT && \
+ SQUARE_STATE((i)+(h), (j)+(v)) == SQUARE_LIT), \
+/* t ? printf("SQUARE_DIAGONAL_VIOLATION(%d, %d, %d, %d)\n",
+ i, j, h, v) : 0,*/ \
+ t)
+
+ /* We also may not light a square if it will form a loop of lit squares
+ * around some unlit squares, as then the game soln won't have a single
+ * loop */
+#define SQUARE_LOOP_VIOLATION(i, j, lit1, lit2) \
+ (SQUARE_STATE((i)+1, (j)) == lit1 && \
+ SQUARE_STATE((i)-1, (j)) == lit1 && \
+ SQUARE_STATE((i), (j)+1) == lit2 && \
+ SQUARE_STATE((i), (j)-1) == lit2)
+
+#define CAN_LIGHT_SQUARE(i, j) \
+ (SQUARE_REACHABLE(i, j) && \
+ !SQUARE_DIAGONAL_VIOLATION(i, j, -1, -1) && \
+ !SQUARE_DIAGONAL_VIOLATION(i, j, +1, -1) && \
+ !SQUARE_DIAGONAL_VIOLATION(i, j, -1, +1) && \
+ !SQUARE_DIAGONAL_VIOLATION(i, j, +1, +1) && \
+ !SQUARE_LOOP_VIOLATION(i, j, SQUARE_LIT, SQUARE_UNLIT) && \
+ !SQUARE_LOOP_VIOLATION(i, j, SQUARE_UNLIT, SQUARE_LIT))
+
+#define IS_LIGHTING_CANDIDATE(i, j) \
+ (SQUARE_STATE(i, j) == SQUARE_UNLIT && \
+ CAN_LIGHT_SQUARE(i,j))
+
+ /* The 'score' of a square reflects its current desirability for selection
+ * as the next square to light. We want to encourage moving into uncharted
+ * areas so we give scores according to how many of the square's neighbours
+ * are currently unlit. */
+
+ /* UNLIT SCORE
+ * 3 2
+ * 2 0
+ * 1 -2
+ */
+#define SQUARE_SCORE(i,j) \
+ (2*((SQUARE_STATE(i-1, j) == SQUARE_UNLIT) + \
+ (SQUARE_STATE(i+1, j) == SQUARE_UNLIT) + \
+ (SQUARE_STATE(i, j-1) == SQUARE_UNLIT) + \
+ (SQUARE_STATE(i, j+1) == SQUARE_UNLIT)) - 4)
+
+ /* When a square gets lit, this defines how far away from that square we
+ * need to go recomputing scores */
+#define SCORE_DISTANCE 1
+
+ board = snewn(board_area, char);
+ clues = snewn(board_area, char);
+
+ state->h = params->h;
+ state->w = params->w;
+ state->clues = clues;
+
+ /* Make a board */
+ memset(board, SQUARE_UNLIT, board_area);
+
+ /* Seed the board with a single lit square near the middle */
+ i = params->w / 2;
+ j = params->h / 2;
+ if (params->w & 1 && random_bits(rs, 1))
+ ++i;
+ if (params->h & 1 && random_bits(rs, 1))
+ ++j;
+
+ LV_SQUARE_STATE(i, j) = SQUARE_LIT;
+
+ /* We need a way of favouring squares that will increase our loopiness.
+ * We do this by maintaining a list of all candidate squares sorted by
+ * their score and choose randomly from that with appropriate skew.
+ * In order to avoid consistently biasing towards particular squares, we
+ * need the sort order _within_ each group of scores to be completely
+ * random. But it would be abusing the hospitality of the tree234 data
+ * structure if our comparison function were nondeterministic :-). So with
+ * each square we associate a random number that does not change during a
+ * particular run of the generator, and use that as a secondary sort key.
+ * Yes, this means we will be biased towards particular random squares in
+ * any one run but that doesn't actually matter. */
+
+ lightable_squares_sorted = newtree234(square_sort_cmpfn);
+ lightable_squares_gettable = newtree234(get_square_cmpfn);
+#define ADD_SQUARE(s) \
+ do { \
+/* printf("ADD SQUARE: [%d,%d], %d, %d\n",
+ s->x, s->y, s->score, s->random);*/ \
+ sq = add234(lightable_squares_sorted, s); \
+ assert(sq == s); \
+ sq = add234(lightable_squares_gettable, s); \
+ assert(sq == s); \
+ } while (0)
+
+#define REMOVE_SQUARE(s) \
+ do { \
+/* printf("DELETE SQUARE: [%d,%d], %d, %d\n",
+ s->x, s->y, s->score, s->random);*/ \
+ sq = del234(lightable_squares_sorted, s); \
+ assert(sq); \
+ sq = del234(lightable_squares_gettable, s); \
+ assert(sq); \
+ } while (0)
+
+#define HANDLE_DIR(a, b) \
+ square = snew(struct square); \
+ square->x = (i)+(a); \
+ square->y = (j)+(b); \
+ square->score = 2; \
+ square->random = random_bits(rs, 31); \
+ ADD_SQUARE(square);
+ HANDLE_DIR(-1, 0);
+ HANDLE_DIR( 1, 0);
+ HANDLE_DIR( 0,-1);
+ HANDLE_DIR( 0, 1);
+#undef HANDLE_DIR
+
+ /* Light squares one at a time until the board is interesting enough */
+ while (TRUE)
+ {
+ /* We have count234(lightable_squares) possibilities, and in
+ * lightable_squares_sorted they are sorted with the most desirable
+ * first. */
+ c = count234(lightable_squares_sorted);
+ if (c == 0)
+ break;
+ assert(c == count234(lightable_squares_gettable));
+
+ /* Check that the best square available is any good */
+ square = (struct square *)index234(lightable_squares_sorted, 0);
+ assert(square);
+
+ if (square->score <= 0)
+ break;
+
+ print_tree(lightable_squares_sorted);
+ assert(square->score == SQUARE_SCORE(square->x, square->y));
+ assert(SQUARE_STATE(square->x, square->y) == SQUARE_UNLIT);
+ assert(square->x >= 0 && square->x < params->w);
+ assert(square->y >= 0 && square->y < params->h);
+/* printf("LIGHT SQUARE: [%d,%d], score = %d\n", square->x, square->y, square->score); */
+
+ /* Update data structures */
+ LV_SQUARE_STATE(square->x, square->y) = SQUARE_LIT;
+ REMOVE_SQUARE(square);
+
+ print_board(params, board);
+
+ /* We might have changed the score of any squares up to 2 units away in
+ * any direction */
+ for (b = -SCORE_DISTANCE; b <= SCORE_DISTANCE; b++) {
+ for (a = -SCORE_DISTANCE; a <= SCORE_DISTANCE; a++) {
+ if (!a && !b)
+ continue;
+ square_pos.x = square->x + a;
+ square_pos.y = square->y + b;
+/* printf("Refreshing score for [%d,%d]:\n", square_pos.x, square_pos.y); */
+ if (square_pos.x < 0 || square_pos.x >= params->w ||
+ square_pos.y < 0 || square_pos.y >= params->h) {
+/* printf(" Out of bounds\n"); */
+ continue;
+ }
+ tmpsquare = find234(lightable_squares_gettable, &square_pos,
+ NULL);
+ if (tmpsquare) {
+/* printf(" Removing\n"); */
+ assert(tmpsquare->x == square_pos.x);
+ assert(tmpsquare->y == square_pos.y);
+ assert(SQUARE_STATE(tmpsquare->x, tmpsquare->y) ==
+ SQUARE_UNLIT);
+ REMOVE_SQUARE(tmpsquare);
+ } else {
+/* printf(" Creating\n"); */
+ tmpsquare = snew(struct square);
+ tmpsquare->x = square_pos.x;
+ tmpsquare->y = square_pos.y;
+ tmpsquare->random = random_bits(rs, 31);
+ }
+ tmpsquare->score = SQUARE_SCORE(tmpsquare->x, tmpsquare->y);
+
+ if (IS_LIGHTING_CANDIDATE(tmpsquare->x, tmpsquare->y)) {
+/* printf(" Adding\n"); */
+ ADD_SQUARE(tmpsquare);
+ } else {
+/* printf(" Destroying\n"); */
+ sfree(tmpsquare);
+ }
+ }
+ }
+/* printf("\n\n"); */
+ }
+
+ while ((square = delpos234(lightable_squares_gettable, 0)) != NULL)
+ sfree(square);
+ freetree234(lightable_squares_gettable);
+ freetree234(lightable_squares_sorted);
+
+ /* Copy out all the clues */
+ for (j = 0; j < params->h; ++j) {
+ for (i = 0; i < params->w; ++i) {
+ c = SQUARE_STATE(i, j);
+ LV_CLUE_AT(state, i, j) = '0';
+ if (SQUARE_STATE(i-1, j) != c) ++LV_CLUE_AT(state, i, j);
+ if (SQUARE_STATE(i+1, j) != c) ++LV_CLUE_AT(state, i, j);
+ if (SQUARE_STATE(i, j-1) != c) ++LV_CLUE_AT(state, i, j);
+ if (SQUARE_STATE(i, j+1) != c) ++LV_CLUE_AT(state, i, j);
+ }
+ }
+
+ sfree(board);
+ return clues;
+}
+
+static solver_state *solve_game_rec(const solver_state *sstate);
+
+static int game_has_unique_soln(const game_state *state)
+{
+ int ret;
+ solver_state *sstate_new;
+ solver_state *sstate = new_solver_state((game_state *)state);
+
+ sstate_new = solve_game_rec(sstate);
+
+ ret = (sstate_new->solver_status == SOLVER_SOLVED);
+
+ free_solver_state(sstate_new);
+ free_solver_state(sstate);
+
+ return ret;
+}
+
+/* Remove clues one at a time at random. */
+static game_state *remove_clues(game_state *state, random_state *rs)
+{
+ int *square_list, squares;
+ game_state *ret = dup_game(state), *saved_ret;
+ int n;
+
+ /* We need to remove some clues. We'll do this by forming a list of all
+ * available equivalence classes, shuffling it, then going along one at a
+ * time clearing every member of each equivalence class, where removing a
+ * class doesn't render the board unsolvable. */
+ squares = state->w * state->h;
+ square_list = snewn(squares, int);
+ for (n = 0; n < squares; ++n) {
+ square_list[n] = n;
+ }
+
+ shuffle(square_list, squares, sizeof(int), rs);
+
+ for (n = 0; n < squares; ++n) {
+ saved_ret = dup_game(ret);
+ LV_CLUE_AT(ret, square_list[n] % state->w,
+ square_list[n] / state->w) = ' ';
+ if (game_has_unique_soln(ret)) {
+ free_game(saved_ret);
+ } else {
+ free_game(ret);
+ ret = saved_ret;
+ }
+ }
+
+ return ret;
+}
+
+static char *validate_desc(game_params *params, char *desc);
+
+static char *new_game_desc(game_params *params, random_state *rs,
+ char **aux, int interactive)
+{
+ /* solution and description both use run-length encoding in obvious ways */
+ char *retval;
+ char *description = snewn(SQUARE_COUNT(params) + 1, char);
+ char *dp = description;
+ int i, j;
+ int empty_count;
+ game_state *state = snew(game_state), *state_new;
+
+ state->h = params->h;
+ state->w = params->w;
+
+ state->hl = snewn(HL_COUNT(params), char);
+ state->vl = snewn(VL_COUNT(params), char);
+ memset(state->hl, LINE_UNKNOWN, HL_COUNT(params));
+ memset(state->vl, LINE_UNKNOWN, VL_COUNT(params));
+
+ state->solved = state->cheated = FALSE;
+ state->recursion_depth = params->rec;
+
+ /* Get a new random solvable board with all its clues filled in. Yes, this
+ * can loop for ever if the params are suitably unfavourable, but
+ * preventing games smaller than 4x4 seems to stop this happening */
+ do {
+ state->clues = new_fullyclued_board(params, rs);
+ } while (!game_has_unique_soln(state));
+
+ state_new = remove_clues(state, rs);
+ free_game(state);
+ state = state_new;
+
+ empty_count = 0;
+ for (j = 0; j < params->h; ++j) {
+ for (i = 0; i < params->w; ++i) {
+ if (CLUE_AT(state, i, j) == ' ') {
+ if (empty_count > 25) {
+ dp += sprintf(dp, "%c", empty_count + 'a' - 1);
+ empty_count = 0;
+ }
+ empty_count++;
+ } else {
+ if (empty_count) {
+ dp += sprintf(dp, "%c", empty_count + 'a' - 1);
+ empty_count = 0;
+ }
+ dp += sprintf(dp, "%c", CLUE_AT(state, i, j));
+ }
+ }
+ }
+ if (empty_count)
+ dp += sprintf(dp, "%c", empty_count + 'a' - 1);
+
+ sfree(state);
+ retval = dupstr(description);
+ sfree(description);
+
+ assert(!validate_desc(params, retval));
+
+ return retval;
+}
+
+/* We require that the params pass the test in validate_params and that the
+ * description fills the entire game area */
+static char *validate_desc(game_params *params, char *desc)
+{
+ int count = 0;
+
+ for (; *desc; ++desc) {
+ if (*desc >= '0' && *desc <= '9') {
+ count++;
+ continue;
+ }
+ if (*desc >= 'a') {
+ count += *desc - 'a' + 1;
+ continue;
+ }
+ return "Unknown character in description";
+ }
+
+ if (count < SQUARE_COUNT(params))
+ return "Description too short for board size";
+ if (count > SQUARE_COUNT(params))
+ return "Description too long for board size";
+
+ return NULL;
+}
+
+static game_state *new_game(midend *me, game_params *params, char *desc)
+{
+ int i,j;
+ game_state *state = snew(game_state);
+ int empties_to_make = 0;
+ int n;
+ const char *dp = desc;
+
+ state->recursion_depth = params->rec;
+
+ state->h = params->h;
+ state->w = params->w;
+
+ state->clues = snewn(SQUARE_COUNT(params), char);
+ state->hl = snewn(HL_COUNT(params), char);
+ state->vl = snewn(VL_COUNT(params), char);
+
+ state->solved = state->cheated = FALSE;
+
+ for (j = 0 ; j < params->h; ++j) {
+ for (i = 0 ; i < params->w; ++i) {
+ if (empties_to_make) {
+ empties_to_make--;
+ LV_CLUE_AT(state, i, j) = ' ';
+ continue;
+ }
+
+ assert(*dp);
+ n = *dp - '0';
+ if (n >=0 && n < 10) {
+ LV_CLUE_AT(state, i, j) = *dp;
+ } else {
+ n = *dp - 'a' + 1;
+ assert(n > 0);
+ LV_CLUE_AT(state, i, j) = ' ';
+ empties_to_make = n - 1;
+ }
+ ++dp;
+ }
+ }
+
+ memset(state->hl, LINE_UNKNOWN, HL_COUNT(params));
+ memset(state->vl, LINE_UNKNOWN, VL_COUNT(params));
+
+ return state;
+}
+
+enum { LOOP_NONE=0, LOOP_SOLN, LOOP_NOT_SOLN };
+
+/* Starting at dot [i,j] moves around 'state' removing lines until it's clear
+ * whether or not the starting dot was on a loop. Returns boolean specifying
+ * whether a loop was found. loop_status calls this and assumes that if state
+ * has any lines set, this function will always remove at least one. */
+static int destructively_find_loop(game_state *state)
+{
+ int a, b, i, j, new_i, new_j, n;
+ char *lp;
+
+ lp = (char *)memchr(state->hl, LINE_YES, HL_COUNT(state));
+ if (!lp) {
+ /* We know we're going to return false but we have to fulfil our
+ * contract */
+ lp = (char *)memchr(state->vl, LINE_YES, VL_COUNT(state));
+ if (lp)
+ *lp = LINE_NO;
+
+ return FALSE;
+ }
+
+ n = lp - state->hl;
+
+ i = n % state->w;
+ j = n / state->w;
+
+ assert(i + j * state->w == n); /* because I'm feeling stupid */
+ /* Save start position */
+ a = i;
+ b = j;
+
+ /* Delete one line from the potential loop */
+ if (LEFTOF_DOT(state, i, j) == LINE_YES) {
+ LV_LEFTOF_DOT(state, i, j) = LINE_NO;
+ i--;
+ } else if (ABOVE_DOT(state, i, j) == LINE_YES) {
+ LV_ABOVE_DOT(state, i, j) = LINE_NO;
+ j--;
+ } else if (RIGHTOF_DOT(state, i, j) == LINE_YES) {
+ LV_RIGHTOF_DOT(state, i, j) = LINE_NO;
+ i++;
+ } else if (BELOW_DOT(state, i, j) == LINE_YES) {
+ LV_BELOW_DOT(state, i, j) = LINE_NO;
+ j++;
+ } else {
+ return FALSE;
+ }
+
+ do {
+ /* From the current position of [i,j] there needs to be exactly one
+ * line */
+ new_i = new_j = -1;
+
+#define HANDLE_DIR(dir_dot, x, y) \
+ if (dir_dot(state, i, j) == LINE_YES) { \
+ if (new_i != -1 || new_j != -1) \
+ return FALSE; \
+ new_i = (i)+(x); \
+ new_j = (j)+(y); \
+ LV_##dir_dot(state, i, j) = LINE_NO; \
+ }
+ HANDLE_DIR(ABOVE_DOT, 0, -1);
+ HANDLE_DIR(BELOW_DOT, 0, +1);
+ HANDLE_DIR(LEFTOF_DOT, -1, 0);
+ HANDLE_DIR(RIGHTOF_DOT, +1, 0);
+#undef HANDLE_DIR
+ if (new_i == -1 || new_j == -1) {
+ return FALSE;
+ }
+
+ i = new_i;
+ j = new_j;
+ } while (i != a || j != b);
+
+ return TRUE;
+}
+
+static int loop_status(game_state *state)
+{
+ int i, j, n;
+ game_state *tmpstate;
+ int loop_found = FALSE, non_loop_found = FALSE, any_lines_found = FALSE;
+
+#define BAD_LOOP_FOUND \
+ do { free_game(tmpstate); return LOOP_NOT_SOLN; } while(0)
+
+ /* Repeatedly look for loops until we either run out of lines to consider
+ * or discover for sure that the board fails on the grounds of having no
+ * loop */
+ tmpstate = dup_game(state);
+
+ while (TRUE) {
+ if (!memchr(tmpstate->hl, LINE_YES, HL_COUNT(tmpstate)) &&
+ !memchr(tmpstate->vl, LINE_YES, VL_COUNT(tmpstate))) {
+ break;
+ }
+ any_lines_found = TRUE;
+
+ if (loop_found)
+ BAD_LOOP_FOUND;
+ if (destructively_find_loop(tmpstate)) {
+ loop_found = TRUE;
+ if (non_loop_found)
+ BAD_LOOP_FOUND;
+ } else {
+ non_loop_found = TRUE;
+ }
+ }
+
+ free_game(tmpstate);
+
+ if (!any_lines_found)
+ return LOOP_NONE;
+
+ if (non_loop_found) {
+ assert(!loop_found); /* should have dealt with this already */
+ return LOOP_NONE;
+ }
+
+ /* Check that every clue is satisfied */
+ for (j = 0; j < state->h; ++j) {
+ for (i = 0; i < state->w; ++i) {
+ n = CLUE_AT(state, i, j);
+ if (n != ' ') {
+ if (square_order(state, i, j, LINE_YES) != n - '0') {
+ return LOOP_NOT_SOLN;
+ }
+ }
+ }
+ }
+
+ return LOOP_SOLN;
+}
+
+/* Sums the lengths of the numbers in range [0,n) */
+/* See equivalent function in solo.c for justification of this. */
+int len_0_to_n(int n)
+{
+ int len = 1; /* Counting 0 as a bit of a special case */
+ int i;
+
+ for (i = 1; i < n; i *= 10) {
+ len += max(n - i, 0);
+ }
+
+ return len;
+}
+
+static char *encode_solve_move(const game_state *state)
+{
+ int len, i, j;
+ char *ret, *p;
+ /* This is going to return a string representing the moves needed to set
+ * every line in a grid to be the same as the ones in 'state'. The exact
+ * length of this string is predictable. */
+
+ len = 1; /* Count the 'S' prefix */
+ /* Numbers in horizontal lines */
+ /* Horizontal lines, x position */
+ len += len_0_to_n(state->w) * (state->h + 1);
+ /* Horizontal lines, y position */
+ len += len_0_to_n(state->h + 1) * (state->w);
+ /* Vertical lines, y position */
+ len += len_0_to_n(state->h) * (state->w + 1);
+ /* Vertical lines, x position */
+ len += len_0_to_n(state->w + 1) * (state->h);
+ /* For each line we also have two letters and a comma */
+ len += 3 * (HL_COUNT(state) + VL_COUNT(state));
+
+ ret = snewn(len + 1, char);
+ p = ret;
+
+ p += sprintf(p, "S");
+
+ for (j = 0; j < state->h + 1; ++j) {
+ for (i = 0; i < state->w; ++i) {
+ switch (RIGHTOF_DOT(state, i, j)) {
+ case LINE_YES:
+ p += sprintf(p, "%d,%dhy", i, j);
+ break;
+ case LINE_NO:
+ p += sprintf(p, "%d,%dhn", i, j);
+ break;
+/* default: */
+ /* I'm going to forgive this because I think the results
+ * are cute. */
+/* assert(!"Solver produced incomplete solution!"); */
+ }
+ }
+ }
+
+ for (j = 0; j < state->h; ++j) {
+ for (i = 0; i < state->w + 1; ++i) {
+ switch (BELOW_DOT(state, i, j)) {
+ case LINE_YES:
+ p += sprintf(p, "%d,%dvy", i, j);
+ break;
+ case LINE_NO:
+ p += sprintf(p, "%d,%dvn", i, j);
+ break;
+/* default: */
+ /* I'm going to forgive this because I think the results
+ * are cute. */
+/* assert(!"Solver produced incomplete solution!"); */
+ }
+ }
+ }
+
+ /* No point in doing sums like that if they're going to be wrong */
+ assert(strlen(ret) <= (size_t)len);
+ return dupstr(ret);
+}
+
+/* BEGIN SOLVER IMPLEMENTATION */
+
+ /* For each pair of lines through each dot we store a bit for whether
+ * exactly one of those lines is ON, and in separate arrays we store whether
+ * at least one is on and whether at most 1 is on. (If we know both or
+ * neither is on that's already stored more directly.) That's six bits per
+ * dot. Bit number n represents the lines shown in dot_type_dirs[n]. */
+
+enum dline {
+ DLINE_VERT = 0,
+ DLINE_HORIZ = 1,
+ DLINE_UL = 2,
+ DLINE_DR = 3,
+ DLINE_UR = 4,
+ DLINE_DL = 5
+};
+
+#define OPP_DLINE(dline) (dline ^ 1)
+
+
+#define SQUARE_DLINES \
+ HANDLE_DLINE(DLINE_UL, RIGHTOF_SQUARE, BELOW_SQUARE, 1, 1); \
+ HANDLE_DLINE(DLINE_UR, LEFTOF_SQUARE, BELOW_SQUARE, 0, 1); \
+ HANDLE_DLINE(DLINE_DL, RIGHTOF_SQUARE, ABOVE_SQUARE, 1, 0); \
+ HANDLE_DLINE(DLINE_DR, LEFTOF_SQUARE, ABOVE_SQUARE, 0, 0);
+
+#define DOT_DLINES \
+ HANDLE_DLINE(DLINE_VERT, ABOVE_DOT, BELOW_DOT); \
+ HANDLE_DLINE(DLINE_HORIZ, LEFTOF_DOT, RIGHTOF_DOT); \
+ HANDLE_DLINE(DLINE_UL, ABOVE_DOT, LEFTOF_DOT); \
+ HANDLE_DLINE(DLINE_UR, ABOVE_DOT, RIGHTOF_DOT); \
+ HANDLE_DLINE(DLINE_DL, BELOW_DOT, LEFTOF_DOT); \
+ HANDLE_DLINE(DLINE_DR, BELOW_DOT, RIGHTOF_DOT);
+
+static void array_setall(char *array, char from, char to, int len)
+{
+ char *p = array, *p_old = p;
+ int len_remaining = len;
+
+ while ((p = memchr(p, from, len_remaining))) {
+ *p = to;
+ len_remaining -= p - p_old;
+ p_old = p;
+ }
+}
+
+
+static int game_states_equal(const game_state *state1,
+ const game_state *state2)
+{
+ /* This deliberately doesn't check _all_ fields, just the ones that make a
+ * game state 'interesting' from the POV of the solver */
+ /* XXX review this */
+ if (state1 == state2)
+ return 1;
+
+ if (!state1 || !state2)
+ return 0;
+
+ if (state1->w != state2->w || state1->h != state2->h)
+ return 0;
+
+ if (memcmp(state1->hl, state2->hl, HL_COUNT(state1)))
+ return 0;
+
+ if (memcmp(state1->vl, state2->vl, VL_COUNT(state1)))
+ return 0;
+
+ return 1;
+}
+
+static int solver_states_equal(const solver_state *sstate1,
+ const solver_state *sstate2)
+{
+ if (!sstate1) {
+ if (!sstate2)
+ return TRUE;
+ else
+ return FALSE;
+ }
+
+ if (!game_states_equal(sstate1->state, sstate2->state)) {
+ return 0;
+ }
+
+ /* XXX fields missing, needs review */
+ /* XXX we're deliberately not looking at solver_state as it's only a cache */
+
+ if (memcmp(sstate1->dot_atleastone, sstate2->dot_atleastone,
+ DOT_COUNT(sstate1->state))) {
+ return 0;
+ }
+
+ if (memcmp(sstate1->dot_atmostone, sstate2->dot_atmostone,
+ DOT_COUNT(sstate1->state))) {
+ return 0;
+ }
+
+ /* handle dline_identical here */
+
+ return 1;
+}
+
+static void dot_setall_dlines(solver_state *sstate, enum dline dl, int i, int j,
+ enum line_state line_old, enum line_state line_new)
+{
+ game_state *state = sstate->state;
+
+ /* First line in dline */
+ switch (dl) {
+ case DLINE_UL:
+ case DLINE_UR:
+ case DLINE_VERT:
+ if (j > 0 && ABOVE_DOT(state, i, j) == line_old)
+ LV_ABOVE_DOT(state, i, j) = line_new;
+ break;
+ case DLINE_DL:
+ case DLINE_DR:
+ if (j <= (state)->h && BELOW_DOT(state, i, j) == line_old)
+ LV_BELOW_DOT(state, i, j) = line_new;
+ break;
+ case DLINE_HORIZ:
+ if (i > 0 && LEFTOF_DOT(state, i, j) == line_old)
+ LV_LEFTOF_DOT(state, i, j) = line_new;
+ break;
+ }
+
+ /* Second line in dline */
+ switch (dl) {
+ case DLINE_UL:
+ case DLINE_DL:
+ if (i > 0 && LEFTOF_DOT(state, i, j) == line_old)
+ LV_LEFTOF_DOT(state, i, j) = line_new;
+ break;
+ case DLINE_UR:
+ case DLINE_DR:
+ case DLINE_HORIZ:
+ if (i <= (state)->w && RIGHTOF_DOT(state, i, j) == line_old)
+ LV_RIGHTOF_DOT(state, i, j) = line_new;
+ break;
+ case DLINE_VERT:
+ if (j <= (state)->h && BELOW_DOT(state, i, j) == line_old)
+ LV_BELOW_DOT(state, i, j) = line_new;
+ break;
+ }
+}
+
+static void update_solver_status(solver_state *sstate)
+{
+ if (sstate->solver_status == SOLVER_INCOMPLETE) {
+ switch (loop_status(sstate->state)) {
+ case LOOP_NONE:
+ sstate->solver_status = SOLVER_INCOMPLETE;
+ break;
+ case LOOP_SOLN:
+ if (sstate->solver_status != SOLVER_AMBIGUOUS)
+ sstate->solver_status = SOLVER_SOLVED;
+ break;
+ case LOOP_NOT_SOLN:
+ sstate->solver_status = SOLVER_MISTAKE;
+ break;
+ }
+ }
+}
+
+
+/* This will return a dynamically allocated solver_state containing the (more)
+ * solved grid */
+static solver_state *solve_game_rec(const solver_state *sstate_start)
+{
+ int i, j;
+ int current_yes, current_no, desired;
+ solver_state *sstate, *sstate_saved, *sstate_tmp;
+ int t;
+/* char *text; */
+ solver_state *sstate_rec_solved;
+ int recursive_soln_count;
+
+#if 0
+ printf("solve_game_rec: recursion_remaining = %d\n",
+ sstate_start->recursion_remaining);
+#endif
+
+ sstate = dup_solver_state((solver_state *)sstate_start);
+
+#if 0
+ text = game_text_format(sstate->state);
+ printf("%s\n", text);
+ sfree(text);
+#endif
+
+#define RETURN_IF_SOLVED \
+ do { \
+ update_solver_status(sstate); \
+ if (sstate->solver_status != SOLVER_INCOMPLETE) { \
+ free_solver_state(sstate_saved); \
+ return sstate; \
+ } \
+ } while (0)
+
+ sstate_saved = NULL;
+ RETURN_IF_SOLVED;
+
+nonrecursive_solver:
+
+ while (1) {
+ sstate_saved = dup_solver_state(sstate);
+
+ /* First we do the 'easy' work, that might cause concrete results */
+
+ /* Per-square deductions */
+ for (j = 0; j < sstate->state->h; ++j) {
+ for (i = 0; i < sstate->state->w; ++i) {
+ /* Begin rules that look at the clue (if there is one) */
+ desired = CLUE_AT(sstate->state, i, j);
+ if (desired == ' ')
+ continue;
+ desired = desired - '0';
+ current_yes = square_order(sstate->state, i, j, LINE_YES);
+ current_no = square_order(sstate->state, i, j, LINE_NO);
+
+ if (desired <= current_yes) {
+ square_setall(sstate->state, i, j, LINE_UNKNOWN, LINE_NO);
+ continue;
+ }
+
+ if (4 - desired <= current_no) {
+ square_setall(sstate->state, i, j, LINE_UNKNOWN, LINE_YES);
+ }
+ }
+ }
+
+ RETURN_IF_SOLVED;
+
+ /* Per-dot deductions */
+ for (j = 0; j < sstate->state->h + 1; ++j) {
+ for (i = 0; i < sstate->state->w + 1; ++i) {
+ switch (dot_order(sstate->state, i, j, LINE_YES)) {
+ case 0:
+ if (dot_order(sstate->state, i, j, LINE_NO) == 3) {
+ dot_setall(sstate->state, i, j, LINE_UNKNOWN, LINE_NO);
+ }
+ break;
+ case 1:
+ switch (dot_order(sstate->state, i, j, LINE_NO)) {
+#define H1(dline, dir1_dot, dir2_dot, dot_howmany) \
+ if (dir1_dot(sstate->state, i, j) == LINE_UNKNOWN) { \
+ if (dir2_dot(sstate->state, i, j) == LINE_UNKNOWN){ \
+ sstate->dot_howmany \
+ [i + (sstate->state->w + 1) * j] |= 1<<dline; \
+ } \
+ }
+ case 1:
+#define HANDLE_DLINE(dline, dir1_dot, dir2_dot) \
+ H1(dline, dir1_dot, dir2_dot, dot_atleastone)
+ /* 1 yes, 1 no, so exactly one of unknowns is yes */
+ DOT_DLINES;
+#undef HANDLE_DLINE
+ /* fall through */
+ case 0:
+#define HANDLE_DLINE(dline, dir1_dot, dir2_dot) \
+ H1(dline, dir1_dot, dir2_dot, dot_atmostone)
+ /* 1 yes, fewer than 2 no, so at most one of
+ * unknowns is yes */
+ DOT_DLINES;
+#undef HANDLE_DLINE
+#undef H1
+ break;
+ case 2: /* 1 yes, 2 no */
+ dot_setall(sstate->state, i, j,
+ LINE_UNKNOWN, LINE_YES);
+ break;
+ }
+ break;
+ case 2:
+ case 3:
+ dot_setall(sstate->state, i, j, LINE_UNKNOWN, LINE_NO);
+ }
+#define HANDLE_DLINE(dline, dir1_dot, dir2_dot) \
+ if (sstate->dot_atleastone \
+ [i + (sstate->state->w + 1) * j] & 1<<dline) { \
+ sstate->dot_atmostone \
+ [i + (sstate->state->w + 1) * j] |= 1<<OPP_DLINE(dline); \
+ }
+ /* If at least one of a dline in a dot is YES, at most one of
+ * the opposite dline to that dot must be YES. */
+ DOT_DLINES;
+#undef HANDLE_DLINE
+ }
+ }
+
+ /* More obscure per-square operations */
+ for (j = 0; j < sstate->state->h; ++j) {
+ for (i = 0; i < sstate->state->w; ++i) {
+#define H1(dline, dir1_sq, dir2_sq, a, b, dot_howmany, line_query, line_set) \
+ if (sstate->dot_howmany[i+a + (sstate->state->w + 1) * (j+b)] &\
+ 1<<dline) { \
+ t = dir1_sq(sstate->state, i, j); \
+ if (t == line_query) \
+ dir2_sq(sstate->state, i, j) = line_set; \
+ else { \
+ t = dir2_sq(sstate->state, i, j); \
+ if (t == line_query) \
+ dir1_sq(sstate->state, i, j) = line_set; \
+ } \
+ }
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ H1(dline, dir1_sq, dir2_sq, a, b, dot_atmostone, \
+ LINE_YES, LINE_NO)
+ /* If at most one of the DLINE is on, and one is definitely on,
+ * set the other to definitely off */
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ H1(dline, dir1_sq, dir2_sq, a, b, dot_atleastone, \
+ LINE_NO, LINE_YES)
+ /* If at least one of the DLINE is on, and one is definitely
+ * off, set the other to definitely on */
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+#undef H1
+
+ switch (CLUE_AT(sstate->state, i, j)) {
+ case '0':
+ case '1':
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ /* At most one of any DLINE can be set */ \
+ sstate->dot_atmostone \
+ [i+a + (sstate->state->w + 1) * (j+b)] |= 1<<dline; \
+ /* This DLINE provides enough YESes to solve the clue */\
+ if (sstate->dot_atleastone \
+ [i+a + (sstate->state->w + 1) * (j+b)] & \
+ 1<<dline) { \
+ dot_setall_dlines(sstate, OPP_DLINE(dline), \
+ i+(1-a), j+(1-b), \
+ LINE_UNKNOWN, LINE_NO); \
+ }
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+ break;
+ case '2':
+#define H1(dline, dot_at1one, dot_at2one, a, b) \
+ if (sstate->dot_at1one \
+ [i+a + (sstate->state->w + 1) * (j+b)] & \
+ 1<<dline) { \
+ sstate->dot_at2one \
+ [i+(1-a) + (sstate->state->w + 1) * (j+(1-b))] |= \
+ 1<<OPP_DLINE(dline); \
+ }
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ H1(dline, dot_atleastone, dot_atmostone, a, b); \
+ H1(dline, dot_atmostone, dot_atleastone, a, b);
+ /* If at least one of one DLINE is set, at most one of
+ * the opposing one is and vice versa */
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+#undef H1
+ break;
+ case '3':
+ case '4':
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ /* At least one of any DLINE can be set */ \
+ sstate->dot_atleastone \
+ [i+a + (sstate->state->w + 1) * (j+b)] |= 1<<dline; \
+ /* This DLINE provides enough NOs to solve the clue */ \
+ if (sstate->dot_atmostone \
+ [i+a + (sstate->state->w + 1) * (j+b)] & \
+ 1<<dline) { \
+ dot_setall_dlines(sstate, OPP_DLINE(dline), \
+ i+(1-a), j+(1-b), \
+ LINE_UNKNOWN, LINE_YES); \
+ }
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+ break;
+ }
+ }
+ }
+
+ if (solver_states_equal(sstate, sstate_saved)) {
+ int edgecount = 0, clues = 0, satclues = 0, sm1clues = 0;
+ int d;
+
+ /*
+ * Go through the grid and update for all the new edges.
+ * Since merge_dots() is idempotent, the simplest way to
+ * do this is just to update for _all_ the edges.
+ *
+ * Also, while we're here, we count the edges, count the
+ * clues, count the satisfied clues, and count the
+ * satisfied-minus-one clues.
+ */
+ for (j = 0; j <= sstate->state->h; ++j) {
+ for (i = 0; i <= sstate->state->w; ++i) {
+ if (RIGHTOF_DOT(sstate->state, i, j) == LINE_YES) {
+ merge_dots(sstate, i, j, i+1, j);
+ edgecount++;
+ }
+ if (BELOW_DOT(sstate->state, i, j) == LINE_YES) {
+ merge_dots(sstate, i, j, i, j+1);
+ edgecount++;
+ }
+
+ if (CLUE_AT(sstate->state, i, j) != ' ') {
+ int c = CLUE_AT(sstate->state, i, j) - '0';
+ int o = square_order(sstate->state, i, j, LINE_YES);
+ if (o == c)
+ satclues++;
+ else if (o == c-1)
+ sm1clues++;
+ clues++;
+ }
+ }
+ }
+
+ /*
+ * Now go through looking for LINE_UNKNOWN edges which
+ * connect two dots that are already in the same
+ * equivalence class. If we find one, test to see if the
+ * loop it would create is a solution.
+ */
+ for (j = 0; j <= sstate->state->h; ++j) {
+ for (i = 0; i <= sstate->state->w; ++i) {
+ for (d = 0; d < 2; d++) {
+ int i2, j2, eqclass, val;
+
+ if (d == 0) {
+ if (RIGHTOF_DOT(sstate->state, i, j) !=
+ LINE_UNKNOWN)
+ continue;
+ i2 = i+1;
+ j2 = j;
+ } else {
+ if (BELOW_DOT(sstate->state, i, j) !=
+ LINE_UNKNOWN)
+ continue;
+ i2 = i;
+ j2 = j+1;
+ }
+
+ eqclass = dsf_canonify(sstate->dotdsf,
+ j * (sstate->state->w+1) + i);
+ if (eqclass != dsf_canonify(sstate->dotdsf,
+ j2 * (sstate->state->w+1) +
+ i2))
+ continue;
+
+ val = LINE_NO; /* loop is bad until proven otherwise */
+
+ /*
+ * This edge would form a loop. Next
+ * question: how long would the loop be?
+ * Would it equal the total number of edges
+ * (plus the one we'd be adding if we added
+ * it)?
+ */
+ if (sstate->looplen[eqclass] == edgecount + 1) {
+ int sm1_nearby;
+ int cx, cy;
+
+ /*
+ * This edge would form a loop which
+ * took in all the edges in the entire
+ * grid. So now we need to work out
+ * whether it would be a valid solution
+ * to the puzzle, which means we have to
+ * check if it satisfies all the clues.
+ * This means that every clue must be
+ * either satisfied or satisfied-minus-
+ * 1, and also that the number of
+ * satisfied-minus-1 clues must be at
+ * most two and they must lie on either
+ * side of this edge.
+ */
+ sm1_nearby = 0;
+ cx = i - (j2-j);
+ cy = j - (i2-i);
+ if (CLUE_AT(sstate->state, cx,cy) != ' ' &&
+ square_order(sstate->state, cx,cy, LINE_YES) ==
+ CLUE_AT(sstate->state, cx,cy) - '0' - 1)
+ sm1_nearby++;
+ if (CLUE_AT(sstate->state, i, j) != ' ' &&
+ square_order(sstate->state, i, j, LINE_YES) ==
+ CLUE_AT(sstate->state, i, j) - '0' - 1)
+ sm1_nearby++;
+ if (sm1clues == sm1_nearby &&
+ sm1clues + satclues == clues)
+ val = LINE_YES; /* loop is good! */
+ }
+
+ /*
+ * Right. Now we know that adding this edge
+ * would form a loop, and we know whether
+ * that loop would be a viable solution or
+ * not.
+ *
+ * If adding this edge produces a solution,
+ * then we know we've found _a_ solution but
+ * we don't know that it's _the_ solution -
+ * if it were provably the solution then
+ * we'd have deduced this edge some time ago
+ * without the need to do loop detection. So
+ * in this state we return SOLVER_AMBIGUOUS,
+ * which has the effect that hitting Solve
+ * on a user-provided puzzle will fill in a
+ * solution but using the solver to
+ * construct new puzzles won't consider this
+ * a reasonable deduction for the user to
+ * make.
+ */
+ if (d == 0)
+ LV_RIGHTOF_DOT(sstate->state, i, j) = val;
+ else
+ LV_BELOW_DOT(sstate->state, i, j) = val;
+ if (val == LINE_YES) {
+ sstate->solver_status = SOLVER_AMBIGUOUS;
+ goto finished_loop_checking;
+ }
+ }
+ }
+ }
+
+ finished_loop_checking:
+
+ RETURN_IF_SOLVED;
+ }
+
+ if (solver_states_equal(sstate, sstate_saved)) {
+ /* Solver has stopped making progress so we terminate */
+ free_solver_state(sstate_saved);
+ break;
+ }
+
+ free_solver_state(sstate_saved);
+ }
+
+ if (sstate->solver_status == SOLVER_SOLVED ||
+ sstate->solver_status == SOLVER_AMBIGUOUS) {
+ /* s/LINE_UNKNOWN/LINE_NO/g */
+ array_setall(sstate->state->hl, LINE_UNKNOWN, LINE_NO,
+ HL_COUNT(sstate->state));
+ array_setall(sstate->state->vl, LINE_UNKNOWN, LINE_NO,
+ VL_COUNT(sstate->state));
+ return sstate;
+ }
+
+ /* Perform recursive calls */
+ if (sstate->recursion_remaining) {
+ sstate->recursion_remaining--;
+
+ sstate_saved = dup_solver_state(sstate);
+
+ recursive_soln_count = 0;
+ sstate_rec_solved = NULL;
+
+ /* Memory management:
+ * sstate_saved won't be modified but needs to be freed when we have
+ * finished with it.
+ * sstate is expected to contain our 'best' solution by the time we
+ * finish this section of code. It's the thing we'll try adding lines
+ * to, seeing if they make it more solvable.
+ * If sstate_rec_solved is non-NULL, it will supersede sstate
+ * eventually. sstate_tmp should not hold a value persistently.
+ */
+
+ /* NB SOLVER_AMBIGUOUS is like SOLVER_SOLVED except the solver is aware
+ * of the possibility of additional solutions. So as soon as we have a
+ * SOLVER_AMBIGUOUS we can safely propagate it back to our caller, but
+ * if we get a SOLVER_SOLVED we want to keep trying in case we find
+ * further solutions and have to mark it ambiguous.
+ */
+
+#define DO_RECURSIVE_CALL(dir_dot) \
+ if (dir_dot(sstate->state, i, j) == LINE_UNKNOWN) { \
+ debug(("Trying " #dir_dot " at [%d,%d]\n", i, j)); \
+ LV_##dir_dot(sstate->state, i, j) = LINE_YES; \
+ sstate_tmp = solve_game_rec(sstate); \
+ switch (sstate_tmp->solver_status) { \
+ case SOLVER_AMBIGUOUS: \
+ debug(("Solver ambiguous, returning\n")); \
+ sstate_rec_solved = sstate_tmp; \
+ goto finished_recursion; \
+ case SOLVER_SOLVED: \
+ switch (++recursive_soln_count) { \
+ case 1: \
+ debug(("One solution found\n")); \
+ sstate_rec_solved = sstate_tmp; \
+ break; \
+ case 2: \
+ debug(("Ambiguous solutions found\n")); \
+ free_solver_state(sstate_tmp); \
+ sstate_rec_solved->solver_status = SOLVER_AMBIGUOUS;\
+ goto finished_recursion; \
+ default: \
+ assert(!"recursive_soln_count out of range"); \
+ break; \
+ } \
+ break; \
+ case SOLVER_MISTAKE: \
+ debug(("Non-solution found\n")); \
+ free_solver_state(sstate_tmp); \
+ free_solver_state(sstate_saved); \
+ LV_##dir_dot(sstate->state, i, j) = LINE_NO; \
+ goto nonrecursive_solver; \
+ case SOLVER_INCOMPLETE: \
+ debug(("Recursive step inconclusive\n")); \
+ free_solver_state(sstate_tmp); \
+ break; \
+ } \
+ free_solver_state(sstate); \
+ sstate = dup_solver_state(sstate_saved); \
+ }
+
+ for (j = 0; j < sstate->state->h + 1; ++j) {
+ for (i = 0; i < sstate->state->w + 1; ++i) {
+ /* Only perform recursive calls on 'loose ends' */
+ if (dot_order(sstate->state, i, j, LINE_YES) == 1) {
+ if (LEFTOF_DOT(sstate->state, i, j) == LINE_UNKNOWN)
+ DO_RECURSIVE_CALL(LEFTOF_DOT);
+ if (RIGHTOF_DOT(sstate->state, i, j) == LINE_UNKNOWN)
+ DO_RECURSIVE_CALL(RIGHTOF_DOT);
+ if (ABOVE_DOT(sstate->state, i, j) == LINE_UNKNOWN)
+ DO_RECURSIVE_CALL(ABOVE_DOT);
+ if (BELOW_DOT(sstate->state, i, j) == LINE_UNKNOWN)
+ DO_RECURSIVE_CALL(BELOW_DOT);
+ }
+ }
+ }
+
+finished_recursion:
+
+ if (sstate_rec_solved) {
+ free_solver_state(sstate);
+ sstate = sstate_rec_solved;
+ }
+ }
+
+ return sstate;
+}
+
+/* XXX bits of solver that may come in handy one day */
+#if 0
+#define HANDLE_DLINE(dline, dir1_dot, dir2_dot) \
+ /* dline from this dot that's entirely unknown must have
+ * both lines identical */ \
+ if (dir1_dot(sstate->state, i, j) == LINE_UNKNOWN && \
+ dir2_dot(sstate->state, i, j) == LINE_UNKNOWN) { \
+ sstate->dline_identical[i + (sstate->state->w + 1) * j] |= \
+ 1<<dline; \
+ } else if (sstate->dline_identical[i +
+ (sstate->state->w + 1) * j] &\
+ 1<<dline) { \
+ /* If they're identical and one is known do the obvious
+ * thing */ \
+ t = dir1_dot(sstate->state, i, j); \
+ if (t != LINE_UNKNOWN) \
+ dir2_dot(sstate->state, i, j) = t; \
+ else { \
+ t = dir2_dot(sstate->state, i, j); \
+ if (t != LINE_UNKNOWN) \
+ dir1_dot(sstate->state, i, j) = t; \
+ } \
+ } \
+ DOT_DLINES;
+#undef HANDLE_DLINE
+#endif
+
+#if 0
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ if (sstate->dline_identical[i+a + \
+ (sstate->state->w + 1) * (j+b)] &\
+ 1<<dline) { \
+ dir1_sq(sstate->state, i, j) = LINE_YES; \
+ dir2_sq(sstate->state, i, j) = LINE_YES; \
+ }
+ /* If two lines are the same they must be on */
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+#endif
+
+
+#if 0
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ if (sstate->dot_atmostone[i+a + (sstate->state->w + 1) * (j+b)] & \
+ 1<<dline) { \
+ if (square_order(sstate->state, i, j, LINE_UNKNOWN) - 1 == \
+ CLUE_AT(sstate->state, i, j) - '0') { \
+ square_setall(sstate->state, i, j, LINE_UNKNOWN, LINE_YES); \
+ /* XXX the following may overwrite known data! */ \
+ dir1_sq(sstate->state, i, j) = LINE_UNKNOWN; \
+ dir2_sq(sstate->state, i, j) = LINE_UNKNOWN; \
+ } \
+ }
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+#endif
+
+#if 0
+#define HANDLE_DLINE(dline, dir1_sq, dir2_sq, a, b) \
+ if (sstate->dline_identical[i+a +
+ (sstate->state->w + 1) * (j+b)] &\
+ 1<<dline) { \
+ dir1_sq(sstate->state, i, j) = LINE_NO; \
+ dir2_sq(sstate->state, i, j) = LINE_NO; \
+ }
+ /* If two lines are the same they must be off */
+ SQUARE_DLINES;
+#undef HANDLE_DLINE
+#endif
+
+static char *solve_game(game_state *state, game_state *currstate,
+ char *aux, char **error)
+{
+ char *soln = NULL;
+ solver_state *sstate, *new_sstate;
+
+ sstate = new_solver_state(state);
+ new_sstate = solve_game_rec(sstate);
+
+ if (new_sstate->solver_status == SOLVER_SOLVED) {
+ soln = encode_solve_move(new_sstate->state);
+ } else if (new_sstate->solver_status == SOLVER_AMBIGUOUS) {
+ soln = encode_solve_move(new_sstate->state);
+ /**error = "Solver found ambiguous solutions"; */
+ } else {
+ soln = encode_solve_move(new_sstate->state);
+ /**error = "Solver failed"; */
+ }
+
+ free_solver_state(new_sstate);
+ free_solver_state(sstate);
+
+ return soln;
+}
+
+static char *game_text_format(game_state *state)
+{
+ int i, j;
+ int len;
+ char *ret, *rp;
+
+ len = (2 * state->w + 2) * (2 * state->h + 1);
+ rp = ret = snewn(len + 1, char);
+
+#define DRAW_HL \
+ switch (ABOVE_SQUARE(state, i, j)) { \
+ case LINE_YES: \
+ rp += sprintf(rp, " -"); \
+ break; \
+ case LINE_NO: \
+ rp += sprintf(rp, " x"); \
+ break; \
+ case LINE_UNKNOWN: \
+ rp += sprintf(rp, " "); \
+ break; \
+ default: \
+ assert(!"Illegal line state for HL");\
+ }
+
+#define DRAW_VL \
+ switch (LEFTOF_SQUARE(state, i, j)) {\
+ case LINE_YES: \
+ rp += sprintf(rp, "|"); \
+ break; \
+ case LINE_NO: \
+ rp += sprintf(rp, "x"); \
+ break; \
+ case LINE_UNKNOWN: \
+ rp += sprintf(rp, " "); \
+ break; \
+ default: \
+ assert(!"Illegal line state for VL");\
+ }
+
+ for (j = 0; j < state->h; ++j) {
+ for (i = 0; i < state->w; ++i) {
+ DRAW_HL;
+ }
+ rp += sprintf(rp, " \n");
+ for (i = 0; i < state->w; ++i) {
+ DRAW_VL;
+ rp += sprintf(rp, "%c", CLUE_AT(state, i, j));
+ }
+ DRAW_VL;
+ rp += sprintf(rp, "\n");
+ }
+ for (i = 0; i < state->w; ++i) {
+ DRAW_HL;
+ }
+ rp += sprintf(rp, " \n");
+
+ assert(strlen(ret) == len);
+ return ret;
+}
+
+static game_ui *new_ui(game_state *state)
+{
+ return NULL;
+}
+
+static void free_ui(game_ui *ui)
+{
+}
+
+static char *encode_ui(game_ui *ui)
+{
+ return NULL;
+}
+
+static void decode_ui(game_ui *ui, char *encoding)
+{
+}
+
+static void game_changed_state(game_ui *ui, game_state *oldstate,
+ game_state *newstate)
+{
+}
+
+struct game_drawstate {
+ int started;
+ int tilesize;
+ int flashing;
+ char *hl, *vl;
+};
+
+static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
+ int x, int y, int button)
+{
+ int hl_selected;
+ int i, j, p, q;
+ char *ret, buf[80];
+ char button_char = ' ';
+ enum line_state old_state;
+
+ button &= ~MOD_MASK;
+
+ /* Around each line is a diamond-shaped region where points within that
+ * region are closer to this line than any other. We assume any click
+ * within a line's diamond was meant for that line. It would all be a lot
+ * simpler if the / and % operators respected modulo arithmetic properly
+ * for negative numbers. */
+
+ x -= BORDER;
+ y -= BORDER;
+
+ /* Get the coordinates of the square the click was in */
+ i = (x + TILE_SIZE) / TILE_SIZE - 1;
+ j = (y + TILE_SIZE) / TILE_SIZE - 1;
+
+ /* Get the precise position inside square [i,j] */
+ p = (x + TILE_SIZE) % TILE_SIZE;
+ q = (y + TILE_SIZE) % TILE_SIZE;
+
+ /* After this bit of magic [i,j] will correspond to the point either above
+ * or to the left of the line selected */
+ if (p > q) {
+ if (TILE_SIZE - p > q) {
+ hl_selected = TRUE;
+ } else {
+ hl_selected = FALSE;
+ ++i;
+ }
+ } else {
+ if (TILE_SIZE - q > p) {
+ hl_selected = FALSE;
+ } else {
+ hl_selected = TRUE;
+ ++j;
+ }
+ }
+
+ if (i < 0 || j < 0)
+ return NULL;
+
+ if (hl_selected) {
+ if (i >= state->w || j >= state->h + 1)
+ return NULL;
+ } else {
+ if (i >= state->w + 1 || j >= state->h)
+ return NULL;
+ }
+
+ /* I think it's only possible to play this game with mouse clicks, sorry */
+ /* Maybe will add mouse drag support some time */
+ if (hl_selected)
+ old_state = RIGHTOF_DOT(state, i, j);
+ else
+ old_state = BELOW_DOT(state, i, j);
+
+ switch (button) {
+ case LEFT_BUTTON:
+ switch (old_state) {
+ case LINE_UNKNOWN:
+ button_char = 'y';
+ break;
+ case LINE_YES:
+ case LINE_NO:
+ button_char = 'u';
+ break;
+ }
+ break;
+ case MIDDLE_BUTTON:
+ button_char = 'u';
+ break;
+ case RIGHT_BUTTON:
+ switch (old_state) {
+ case LINE_UNKNOWN:
+ button_char = 'n';
+ break;
+ case LINE_NO:
+ case LINE_YES:
+ button_char = 'u';
+ break;
+ }
+ break;
+ default:
+ return NULL;
+ }
+
+
+ sprintf(buf, "%d,%d%c%c", i, j, hl_selected ? 'h' : 'v', button_char);
+ ret = dupstr(buf);
+
+ return ret;
+}
+
+static game_state *execute_move(game_state *state, char *move)
+{
+ int i, j;
+ game_state *newstate = dup_game(state);
+
+ if (move[0] == 'S') {
+ move++;
+ newstate->cheated = TRUE;
+ }
+
+ while (*move) {
+ i = atoi(move);
+ move = strchr(move, ',');
+ if (!move)
+ goto fail;
+ j = atoi(++move);
+ move += strspn(move, "1234567890");
+ switch (*(move++)) {
+ case 'h':
+ if (i >= newstate->w || j > newstate->h)
+ goto fail;
+ switch (*(move++)) {
+ case 'y':
+ LV_RIGHTOF_DOT(newstate, i, j) = LINE_YES;
+ break;
+ case 'n':
+ LV_RIGHTOF_DOT(newstate, i, j) = LINE_NO;
+ break;
+ case 'u':
+ LV_RIGHTOF_DOT(newstate, i, j) = LINE_UNKNOWN;
+ break;
+ default:
+ goto fail;
+ }
+ break;
+ case 'v':
+ if (i > newstate->w || j >= newstate->h)
+ goto fail;
+ switch (*(move++)) {
+ case 'y':
+ LV_BELOW_DOT(newstate, i, j) = LINE_YES;
+ break;
+ case 'n':
+ LV_BELOW_DOT(newstate, i, j) = LINE_NO;
+ break;
+ case 'u':
+ LV_BELOW_DOT(newstate, i, j) = LINE_UNKNOWN;
+ break;
+ default:
+ goto fail;
+ }
+ break;
+ default:
+ goto fail;
+ }
+ }
+
+ /*
+ * Check for completion.
+ */
+ for (j = 0; j <= newstate->h; j++) {
+ for (i = 0; i < newstate->w; i++)
+ if (LV_RIGHTOF_DOT(newstate, i, j) == LINE_YES)
+ break;
+ if (i < newstate->w)
+ break;
+ }
+ if (j <= newstate->h) {
+ int prevdir = 'R';
+ int x = i, y = j;
+ int looplen, count;
+
+ /*
+ * We've found a horizontal edge at (i,j). Follow it round
+ * to see if it's part of a loop.
+ */
+ looplen = 0;
+ while (1) {
+ int order = dot_order(newstate, x, y, LINE_YES);
+ if (order != 2)
+ goto completion_check_done;
+
+ if (LEFTOF_DOT(newstate, x, y) == LINE_YES && prevdir != 'L') {
+ x--;
+ prevdir = 'R';
+ } else if (RIGHTOF_DOT(newstate, x, y) == LINE_YES &&
+ prevdir != 'R') {
+ x++;
+ prevdir = 'L';
+ } else if (ABOVE_DOT(newstate, x, y) == LINE_YES &&
+ prevdir != 'U') {
+ y--;
+ prevdir = 'D';
+ } else if (BELOW_DOT(newstate, x, y) == LINE_YES &&
+ prevdir != 'D') {
+ y++;
+ prevdir = 'U';
+ } else {
+ assert(!"Can't happen"); /* dot_order guarantees success */
+ }
+
+ looplen++;
+
+ if (x == i && y == j)
+ break;
+ }
+
+ if (x != i || y != j || looplen == 0)
+ goto completion_check_done;
+
+ /*
+ * We've traced our way round a loop, and we know how many
+ * line segments were involved. Count _all_ the line
+ * segments in the grid, to see if the loop includes them
+ * all.
+ */
+ count = 0;
+ for (j = 0; j <= newstate->h; j++)
+ for (i = 0; i <= newstate->w; i++)
+ count += ((RIGHTOF_DOT(newstate, i, j) == LINE_YES) +
+ (BELOW_DOT(newstate, i, j) == LINE_YES));
+ assert(count >= looplen);
+ if (count != looplen)
+ goto completion_check_done;
+
+ /*
+ * The grid contains one closed loop and nothing else.
+ * Check that all the clues are satisfied.
+ */
+ for (j = 0; j < newstate->h; ++j) {
+ for (i = 0; i < newstate->w; ++i) {
+ int n = CLUE_AT(newstate, i, j);
+ if (n != ' ') {
+ if (square_order(newstate, i, j, LINE_YES) != n - '0') {
+ goto completion_check_done;
+ }
+ }
+ }
+ }
+
+ /*
+ * Completed!
+ */
+ newstate->solved = TRUE;
+ }
+
+completion_check_done:
+ return newstate;
+
+fail:
+ free_game(newstate);
+ return NULL;
+}
+
+/* ----------------------------------------------------------------------
+ * Drawing routines.
+ */
+
+#define SIZE(d) ((d) * TILE_SIZE + 2 * BORDER + 1)
+
+static void game_compute_size(game_params *params, int tilesize,
+ int *x, int *y)
+{
+ struct { int tilesize; } ads, *ds = &ads;
+ ads.tilesize = tilesize;
+
+ *x = SIZE(params->w);
+ *y = SIZE(params->h);
+}
+
+static void game_set_size(drawing *dr, game_drawstate *ds,
+ game_params *params, int tilesize)
+{
+ ds->tilesize = tilesize;
+}
+
+static float *game_colours(frontend *fe, game_state *state, int *ncolours)
+{
+ float *ret = snewn(4 * NCOLOURS, float);
+
+ frontend_default_colour(fe, &ret[COL_BACKGROUND * 3]);
+
+ ret[COL_FOREGROUND * 3 + 0] = 0.0F;
+ ret[COL_FOREGROUND * 3 + 1] = 0.0F;
+ ret[COL_FOREGROUND * 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;
+
+ *ncolours = NCOLOURS;
+ return ret;
+}
+
+static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
+{
+ struct game_drawstate *ds = snew(struct game_drawstate);
+
+ ds->tilesize = 0;
+ ds->started = 0;
+ ds->hl = snewn(HL_COUNT(state), char);
+ ds->vl = snewn(VL_COUNT(state), char);
+ ds->flashing = 0;
+
+ memset(ds->hl, LINE_UNKNOWN, HL_COUNT(state));
+ memset(ds->vl, LINE_UNKNOWN, VL_COUNT(state));
+
+ return ds;
+}
+
+static void game_free_drawstate(drawing *dr, game_drawstate *ds)
+{
+ sfree(ds->hl);
+ sfree(ds->vl);
+ sfree(ds);
+}
+
+static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
+ game_state *state, int dir, game_ui *ui,
+ float animtime, float flashtime)
+{
+ int i, j;
+ int w = state->w, h = state->h;
+ char c[2];
+ int line_colour, flash_changed;
+
+ if (!ds->started) {
+ /*
+ * The initial contents of the window are not guaranteed and
+ * can vary with front ends. To be on the safe side, all games
+ * should start by drawing a big background-colour rectangle
+ * covering the whole window.
+ */
+ draw_rect(dr, 0, 0, SIZE(state->w), SIZE(state->h), COL_BACKGROUND);
+
+ /* Draw dots */
+ for (j = 0; j < h + 1; ++j) {
+ for (i = 0; i < w + 1; ++i) {
+ draw_rect(dr,
+ BORDER + i * TILE_SIZE - LINEWIDTH/2,
+ BORDER + j * TILE_SIZE - LINEWIDTH/2,
+ LINEWIDTH, LINEWIDTH, COL_FOREGROUND);
+ }
+ }
+
+ /* Draw clues */
+ for (j = 0; j < h; ++j) {
+ for (i = 0; i < w; ++i) {
+ c[0] = CLUE_AT(state, i, j);
+ c[1] = '\0';
+ draw_text(dr,
+ BORDER + i * TILE_SIZE + TILE_SIZE/2,
+ BORDER + j * TILE_SIZE + TILE_SIZE/2,
+ FONT_VARIABLE, TILE_SIZE/2,
+ ALIGN_VCENTRE | ALIGN_HCENTRE, COL_FOREGROUND, c);
+ }
+ }
+ draw_update(dr, 0, 0,
+ state->w * TILE_SIZE + 2*BORDER + 1,
+ state->h * TILE_SIZE + 2*BORDER + 1);
+ ds->started = TRUE;
+ }
+
+ if (flashtime > 0 &&
+ (flashtime <= FLASH_TIME/3 ||
+ flashtime >= FLASH_TIME*2/3)) {
+ flash_changed = !ds->flashing;
+ ds->flashing = TRUE;
+ line_colour = COL_HIGHLIGHT;
+ } else {
+ flash_changed = ds->flashing;
+ ds->flashing = FALSE;
+ line_colour = COL_FOREGROUND;
+ }
+
+#define CROSS_SIZE (3 * LINEWIDTH / 2)
+
+#define CLEAR_VL(i, j) do { \
+ draw_rect(dr, \
+ BORDER + i * TILE_SIZE - CROSS_SIZE, \
+ BORDER + j * TILE_SIZE + LINEWIDTH/2, \
+ CROSS_SIZE * 2, \
+ TILE_SIZE - LINEWIDTH, \
+ COL_BACKGROUND); \
+ draw_update(dr, \
+ BORDER + i * TILE_SIZE - CROSS_SIZE, \
+ BORDER + j * TILE_SIZE - CROSS_SIZE, \
+ CROSS_SIZE*2, \
+ TILE_SIZE + CROSS_SIZE*2); \
+ } while (0)
+
+#define CLEAR_HL(i, j) do { \
+ draw_rect(dr, \
+ BORDER + i * TILE_SIZE + LINEWIDTH/2, \
+ BORDER + j * TILE_SIZE - CROSS_SIZE, \
+ TILE_SIZE - LINEWIDTH, \
+ CROSS_SIZE * 2, \
+ COL_BACKGROUND); \
+ draw_update(dr, \
+ BORDER + i * TILE_SIZE - CROSS_SIZE, \
+ BORDER + j * TILE_SIZE - CROSS_SIZE, \
+ TILE_SIZE + CROSS_SIZE*2, \
+ CROSS_SIZE*2); \
+ } while (0)
+
+ /* Vertical lines */
+ for (j = 0; j < h; ++j) {
+ for (i = 0; i < w + 1; ++i) {
+ switch (BELOW_DOT(state, i, j)) {
+ case LINE_UNKNOWN:
+ if (ds->vl[i + (w + 1) * j] != BELOW_DOT(state, i, j)) {
+ CLEAR_VL(i, j);
+ }
+ break;
+ case LINE_YES:
+ if (ds->vl[i + (w + 1) * j] != BELOW_DOT(state, i, j) ||
+ flash_changed) {
+ CLEAR_VL(i, j);
+ draw_rect(dr,
+ BORDER + i * TILE_SIZE - LINEWIDTH/2,
+ BORDER + j * TILE_SIZE + LINEWIDTH/2,
+ LINEWIDTH, TILE_SIZE - LINEWIDTH,
+ line_colour);
+ }
+ break;
+ case LINE_NO:
+ if (ds->vl[i + (w + 1) * j] != BELOW_DOT(state, i, j)) {
+ CLEAR_VL(i, j);
+ draw_line(dr,
+ BORDER + i * TILE_SIZE - CROSS_SIZE,
+ BORDER + j * TILE_SIZE + TILE_SIZE/2 - CROSS_SIZE,
+ BORDER + i * TILE_SIZE + CROSS_SIZE - 1,
+ BORDER + j * TILE_SIZE + TILE_SIZE/2 + CROSS_SIZE - 1,
+ COL_FOREGROUND);
+ draw_line(dr,
+ BORDER + i * TILE_SIZE + CROSS_SIZE - 1,
+ BORDER + j * TILE_SIZE + TILE_SIZE/2 - CROSS_SIZE,
+ BORDER + i * TILE_SIZE - CROSS_SIZE,
+ BORDER + j * TILE_SIZE + TILE_SIZE/2 + CROSS_SIZE - 1,
+ COL_FOREGROUND);
+ }
+ break;
+ }
+ ds->vl[i + (w + 1) * j] = BELOW_DOT(state, i, j);
+ }
+ }
+
+ /* Horizontal lines */
+ for (j = 0; j < h + 1; ++j) {
+ for (i = 0; i < w; ++i) {
+ switch (RIGHTOF_DOT(state, i, j)) {
+ case LINE_UNKNOWN:
+ if (ds->hl[i + w * j] != RIGHTOF_DOT(state, i, j)) {
+ CLEAR_HL(i, j);
+ }
+ break;
+ case LINE_YES:
+ if (ds->hl[i + w * j] != RIGHTOF_DOT(state, i, j) ||
+ flash_changed) {
+ CLEAR_HL(i, j);
+ draw_rect(dr,
+ BORDER + i * TILE_SIZE + LINEWIDTH/2,
+ BORDER + j * TILE_SIZE - LINEWIDTH/2,
+ TILE_SIZE - LINEWIDTH, LINEWIDTH,
+ line_colour);
+ break;
+ }
+ case LINE_NO:
+ if (ds->hl[i + w * j] != RIGHTOF_DOT(state, i, j)) {
+ CLEAR_HL(i, j);
+ draw_line(dr,
+ BORDER + i * TILE_SIZE + TILE_SIZE/2 - CROSS_SIZE,
+ BORDER + j * TILE_SIZE + CROSS_SIZE - 1,
+ BORDER + i * TILE_SIZE + TILE_SIZE/2 + CROSS_SIZE - 1,
+ BORDER + j * TILE_SIZE - CROSS_SIZE,
+ COL_FOREGROUND);
+ draw_line(dr,
+ BORDER + i * TILE_SIZE + TILE_SIZE/2 - CROSS_SIZE,
+ BORDER + j * TILE_SIZE - CROSS_SIZE,
+ BORDER + i * TILE_SIZE + TILE_SIZE/2 + CROSS_SIZE - 1,
+ BORDER + j * TILE_SIZE + CROSS_SIZE - 1,
+ COL_FOREGROUND);
+ break;
+ }
+ }
+ ds->hl[i + w * j] = RIGHTOF_DOT(state, i, j);
+ }
+ }
+}
+
+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 (!oldstate->solved && newstate->solved &&
+ !oldstate->cheated && !newstate->cheated) {
+ return FLASH_TIME;
+ }
+
+ return 0.0F;
+}
+
+static int game_wants_statusbar(void)
+{
+ return FALSE;
+}
+
+static int game_timing_state(game_state *state, game_ui *ui)
+{
+ return TRUE;
+}
+
+static void game_print_size(game_params *params, float *x, float *y)
+{
+ int pw, ph;
+
+ /*
+ * I'll use 7mm squares by default.
+ */
+ game_compute_size(params, 700, &pw, &ph);
+ *x = pw / 100.0F;
+ *y = ph / 100.0F;
+}
+
+static void game_print(drawing *dr, game_state *state, int tilesize)
+{
+ int w = state->w, h = state->h;
+ int ink = print_mono_colour(dr, 0);
+ int x, y;
+ game_drawstate ads, *ds = &ads;
+ ds->tilesize = tilesize;
+
+ /*
+ * Dots. I'll deliberately make the dots a bit wider than the
+ * lines, so you can still see them. (And also because it's
+ * annoyingly tricky to make them _exactly_ the same size...)
+ */
+ for (y = 0; y <= h; y++)
+ for (x = 0; x <= w; x++)
+ draw_circle(dr, BORDER + x * TILE_SIZE, BORDER + y * TILE_SIZE,
+ LINEWIDTH, ink, ink);
+
+ /*
+ * Clues.
+ */
+ for (y = 0; y < h; y++)
+ for (x = 0; x < w; x++)
+ if (CLUE_AT(state, x, y) != ' ') {
+ char c[2];
+
+ c[0] = CLUE_AT(state, x, y);
+ c[1] = '\0';
+ draw_text(dr,
+ BORDER + x * TILE_SIZE + TILE_SIZE/2,
+ BORDER + y * TILE_SIZE + TILE_SIZE/2,
+ FONT_VARIABLE, TILE_SIZE/2,
+ ALIGN_VCENTRE | ALIGN_HCENTRE, ink, c);
+ }
+
+ /*
+ * Lines. (At the moment, I'm not bothering with crosses.)
+ */
+ for (y = 0; y <= h; y++)
+ for (x = 0; x < w; x++)
+ if (RIGHTOF_DOT(state, x, y) == LINE_YES)
+ draw_rect(dr, BORDER + x * TILE_SIZE,
+ BORDER + y * TILE_SIZE - LINEWIDTH/2,
+ TILE_SIZE, (LINEWIDTH/2) * 2 + 1, ink);
+ for (y = 0; y < h; y++)
+ for (x = 0; x <= w; x++)
+ if (BELOW_DOT(state, x, y) == LINE_YES)
+ draw_rect(dr, BORDER + x * TILE_SIZE - LINEWIDTH/2,
+ BORDER + y * TILE_SIZE,
+ (LINEWIDTH/2) * 2 + 1, TILE_SIZE, ink);
+}
+
+#ifdef COMBINED
+#define thegame loopy
+#endif
+
+const struct game thegame = {
+ "Loopy", "games.loopy",
+ default_params,
+ game_fetch_preset,
+ decode_params,
+ encode_params,
+ free_params,
+ dup_params,
+ TRUE, game_configure, custom_params,
+ validate_params,
+ new_game_desc,
+ validate_desc,
+ new_game,
+ dup_game,
+ free_game,
+ 1, solve_game,
+ TRUE, game_text_format,
+ new_ui,
+ free_ui,
+ encode_ui,
+ decode_ui,
+ game_changed_state,
+ interpret_move,
+ execute_move,
+ PREFERRED_TILE_SIZE, game_compute_size, game_set_size,
+ game_colours,
+ game_new_drawstate,
+ game_free_drawstate,
+ game_redraw,
+ game_anim_length,
+ game_flash_length,
+ TRUE, FALSE, game_print_size, game_print,
+ game_wants_statusbar,
+ FALSE, game_timing_state,
+ 0, /* mouse_priorities */
+};
~mdw / sgt / puzzles / commitdiff