Re-architecting of the game backend interface. make_move() has been

split into two functions. The first, interpret_move(), takes all the
arguments that make_move() used to get and may have the usual side
effects of modifying the game_ui, but instead of returning a
modified game_state it instead returns a string description of the
move to be made. This string description is then passed to a second
function, execute_move(), together with an input game_state, which
is responsible for actually producing the new state. (solve_game()
also returns a string to be passed to execute_move().)

The point of this is to work towards being able to serialise the
whole of a game midend into a byte stream such as a disk file, which
will eventually support save and load functions in the desktop
puzzles, as well as restoring half-finished games after a quit and
restart in James Harvey's Palm port. Making each game supply a
convert-to-string function for its game_state format would have been
an unreliable way to do this, since those functions would not have
been used in normal play, so they'd only have been tested when you
actually tried to save and load - a recipe for latent bugs if ever I
heard one. This way, you won't even be able to _make_ a move if
execute_move() doesn't work properly, which means that if you can
play a game at all I can have pretty high confidence that
serialising it will work first time.

This is only the groundwork; there will be more checkins to come on
this theme. But the major upheaval should now be done, and as far as
I can tell everything's still working normally.

[originally from svn r6024]

1 files changed, 89 insertions, 44 deletions

diff --git a/guess.c b/guess.c
index 702a1ad..f3738c0 100644
--- a/guess.c
+++ b/guess.c
@@ -364,12 +364,10 @@ static void free_game(game_state *state)
     sfree(state);
 }
 
-static game_state *solve_game(game_state *state, game_state *currstate,
-                              game_aux_info *aux, char **error)
+static char *solve_game(game_state *state, game_state *currstate,
+			game_aux_info *aux, char **error)
 {
-    game_state *ret = dup_game(currstate);
-    ret->solved = 1;
-    return ret;
+    return dupstr("S");
 }
 
 static char *game_text_format(game_state *state)
@@ -548,47 +546,52 @@ static int mark_pegs(pegrow guess, pegrow solution, int ncols)
     return nc_place;
 }
 
-static game_state *mark_move(game_state *from, game_ui *ui)
+static char *encode_move(game_state *from, game_ui *ui)
 {
-    int i, ncleared = 0, nc_place;
-    game_state *to = dup_game(from);
-
-    for (i = 0; i < to->solution->npegs; i++) {
-        to->guesses[from->next_go]->pegs[i] = ui->curr_pegs->pegs[i];
-    }
-    nc_place = mark_pegs(to->guesses[from->next_go], to->solution, to->params.ncolours);
-
-    if (nc_place == to->solution->npegs) {
-        to->solved = 1; /* win! */
-    } else {
-        to->next_go = from->next_go + 1;
-        if (to->next_go >= to->params.nguesses)
-            to->solved = 1; /* 'lose' so we show the pegs. */
+    char *buf, *p, *sep;
+    int len, i, solved;
+    pegrow tmppegs;
+
+    len = ui->curr_pegs->npegs * 20 + 2;
+    buf = snewn(len, char);
+    p = buf;
+    *p++ = 'G';
+    sep = "";
+    for (i = 0; i < ui->curr_pegs->npegs; i++) {
+	p += sprintf(p, "%s%d", sep, ui->curr_pegs->pegs[i]);
+	sep = ",";
     }
-
-    for (i = 0; i < to->solution->npegs; i++) {
-        if (!ui->holds[i] || to->solved) {
-            ui->curr_pegs->pegs[i] = 0;
-            ncleared++;
-        }
-        if (to->solved) ui->holds[i] = 0;
+    *p++ = '\0';
+    assert(p - buf <= len);
+    buf = sresize(buf, len, char);
+
+    tmppegs = dup_pegrow(ui->curr_pegs);
+    solved = mark_pegs(tmppegs, from->solution, from->params.ncolours);
+    solved = (solved == from->params.ncolours);
+    free_pegrow(tmppegs);
+
+    for (i = 0; i < from->solution->npegs; i++) {
+	if (!ui->holds[i] || solved) {
+	    ui->curr_pegs->pegs[i] = 0;
+	}
+	if (solved) ui->holds[i] = 0;
     }
     ui->markable = is_markable(&from->params, ui->curr_pegs);
-    if (!ui->markable && ui->peg_cur == to->solution->npegs)
-        ui->peg_cur--;
+    if (!ui->markable && ui->peg_cur == from->solution->npegs)
+	ui->peg_cur--;
 
-    return to;
+    return buf;
 }
 
-static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
-                             int x, int y, int button)
+static char *interpret_move(game_state *from, game_ui *ui, game_drawstate *ds,
+			    int x, int y, int button)
 {
     int over_col = 0;           /* one-indexed */
     int over_guess = -1;        /* zero-indexed */
     int over_past_guess_y = -1; /* zero-indexed */
     int over_past_guess_x = -1; /* zero-indexed */
     int over_hint = 0;          /* zero or one */
-    game_state *ret = NULL;
+    char *ret = NULL;
 
     int guess_ox = GUESS_X(from->next_go, 0);
     int guess_oy = GUESS_Y(from->next_go, 0);
@@ -643,13 +646,13 @@ static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
             ui->drag_y = y;
             debug(("Start dragging, col = %d, (%d,%d)",
                    ui->drag_col, ui->drag_x, ui->drag_y));
-            ret = from;
+            ret = "";
         }
     } else if (button == LEFT_DRAG && ui->drag_col) {
         ui->drag_x = x;
         ui->drag_y = y;
         debug(("Keep dragging, (%d,%d)", ui->drag_x, ui->drag_y));
-        ret = from;
+        ret = "";
     } else if (button == LEFT_RELEASE && ui->drag_col) {
         if (over_guess > -1) {
             debug(("Dropping colour %d onto guess peg %d",
@@ -666,18 +669,18 @@ static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
         ui->drag_opeg = -1;
         ui->display_cur = 0;
         debug(("Stop dragging."));
-        ret = from;
+        ret = "";
     } else if (button == RIGHT_BUTTON) {
         if (over_guess > -1) {
             /* we use ths feedback in the game_ui to signify
              * 'carry this peg to the next guess as well'. */
             ui->holds[over_guess] = 1 - ui->holds[over_guess];
-            ret = from;
+            ret = "";
         }
     } else if (button == LEFT_RELEASE && over_hint && ui->markable) {
         /* NB this won't trigger if on the end of a drag; that's on
          * purpose, in case you drop by mistake... */
-        ret = mark_move(from, ui);
+        ret = encode_move(from, ui);
     }
 
     /* keyboard input */
@@ -687,7 +690,7 @@ static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
             ui->colour_cur++;
         if (button == CURSOR_UP && ui->colour_cur > 0)
             ui->colour_cur--;
-        ret = from;
+        ret = "";
     } else if (button == CURSOR_LEFT || button == CURSOR_RIGHT) {
         int maxcur = from->params.npegs;
         if (ui->markable) maxcur++;
@@ -697,24 +700,65 @@ static game_state *make_move(game_state *from, game_ui *ui, game_drawstate *ds,
             ui->peg_cur++;
         if (button == CURSOR_LEFT && ui->peg_cur > 0)
             ui->peg_cur--;
-        ret = from;
+        ret = "";
     } else if (button == CURSOR_SELECT || button == ' ' || button == '\r' ||
                button == '\n') {
         ui->display_cur = 1;
         if (ui->peg_cur == from->params.npegs) {
-            ret = mark_move(from, ui);
+            ret = encode_move(from, ui);
         } else {
             set_peg(&from->params, ui, ui->peg_cur, ui->colour_cur+1);
-            ret = from;
+            ret = "";
         }
     } else if (button == 'H' || button == 'h') {
         ui->display_cur = 1;
         ui->holds[ui->peg_cur] = 1 - ui->holds[ui->peg_cur];
-        ret = from;
+        ret = "";
     }
     return ret;
 }
 
+static game_state *execute_move(game_state *from, char *move)
+{
+    int i, nc_place;
+    game_state *ret;
+    char *p;
+
+    if (!strcmp(move, "S")) {
+	ret = dup_game(from);
+	ret->solved = 1;
+	return ret;
+    } else if (move[0] == 'G') {
+	p = move+1;
+
+	ret = dup_game(from);
+
+	for (i = 0; i < from->solution->npegs; i++) {
+	    int val = atoi(p);
+	    if (val <= 0 || val > from->params.ncolours) {
+		free_game(ret);
+		return NULL;
+	    }
+	    ret->guesses[from->next_go]->pegs[i] = atoi(p);
+	    while (*p && isdigit((unsigned char)*p)) p++;
+	    if (*p == ',') p++;
+	}
+
+	nc_place = mark_pegs(ret->guesses[from->next_go], ret->solution, ret->params.ncolours);
+
+	if (nc_place == ret->solution->npegs) {
+	    ret->solved = 1; /* win! */
+	} else {
+	    ret->next_go = from->next_go + 1;
+	    if (ret->next_go >= ret->params.nguesses)
+		ret->solved = 1; /* 'lose' so we show the pegs. */
+	}
+
+	return ret;
+    } else
+	return NULL;
+}
+
 /* ----------------------------------------------------------------------
  * Drawing routines.
  */
@@ -1217,7 +1261,8 @@ const struct game thegame = {
     new_ui,
     free_ui,
     game_changed_state,
-    make_move,
+    interpret_move,
+    execute_move,
     game_size,
     game_colours,
     game_new_drawstate,