X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/puzzles/blobdiff_plain/ab53eb64790d5bee44525c3a50a420a6816e2495..acc7c231cc4a80bd0d2e2e9bad66a4b2bf3e7f49:/midend.c

diff --git a/midend.c b/midend.c
index b6b1720..e0e9cb0 100644
--- a/midend.c
+++ b/midend.c
@@ -15,9 +15,14 @@
 
 enum { DEF_PARAMS, DEF_SEED, DEF_DESC };   /* for midend_game_id_int */
 
+enum { NEWGAME, MOVE, SOLVE, RESTART };/* for midend_state_entry.movetype */
+
+#define special(type) ( (type) != MOVE )
+
 struct midend_state_entry {
     game_state *state;
-    int special;                       /* created by solve or restart */
+    char *movestr;
+    int movetype;
 };
 
 struct midend_data {
@@ -25,20 +30,44 @@ struct midend_data {
     random_state *random;
     const game *ourgame;
 
-    char *desc, *seedstr;
-    game_aux_info *aux_info;
-    enum { GOT_SEED, GOT_DESC, GOT_NOTHING } genmode;
-    int nstates, statesize, statepos;
-
     game_params **presets;
     char **preset_names;
     int npresets, presetsize;
 
-    game_params *params, *curparams;
+    /*
+     * `desc' and `privdesc' deserve a comment.
+     * 
+     * `desc' is the game description as presented to the user when
+     * they ask for Game -> Specific. `privdesc', if non-NULL, is a
+     * different game description used to reconstruct the initial
+     * game_state when de-serialising. If privdesc is NULL, `desc'
+     * is used for both.
+     * 
+     * For almost all games, `privdesc' is NULL and never used. The
+     * exception (as usual) is Mines: the initial game state has no
+     * squares open at all, but after the first click `desc' is
+     * rewritten to describe a game state with an initial click and
+     * thus a bunch of squares open. If we used that desc to
+     * serialise and deserialise, then the initial game state after
+     * deserialisation would look unlike the initial game state
+     * beforehand, and worse still execute_move() might fail on the
+     * attempted first click. So `privdesc' is also used in this
+     * case, to provide a game description describing the same
+     * fixed mine layout _but_ no initial click. (These game IDs
+     * may also be typed directly into Mines if you like.)
+     */
+    char *desc, *privdesc, *seedstr;
+    char *aux_info;
+    enum { GOT_SEED, GOT_DESC, GOT_NOTHING } genmode;
+
+    int nstates, statesize, statepos;
     struct midend_state_entry *states;
+
+    game_params *params, *curparams;
     game_drawstate *drawstate;
-    game_state *oldstate;
     game_ui *ui;
+
+    game_state *oldstate;
     float anim_time, anim_pos;
     float flash_time, flash_pos;
     int dir;
@@ -48,6 +77,8 @@ struct midend_data {
     char *laststatus;
 
     int pressed_mouse_button;
+
+    int winwidth, winheight;
 };
 
 #define ensure(me) do { \
@@ -73,7 +104,7 @@ midend_data *midend_new(frontend *fe, const game *ourgame)
     me->states = NULL;
     me->params = ourgame->default_params();
     me->curparams = NULL;
-    me->desc = NULL;
+    me->desc = me->privdesc = NULL;
     me->seedstr = NULL;
     me->aux_info = NULL;
     me->genmode = GOT_NOTHING;
@@ -90,6 +121,7 @@ midend_data *midend_new(frontend *fe, const game *ourgame)
     me->laststatus = NULL;
     me->timing = FALSE;
     me->elapsed = 0.0F;
+    me->winwidth = me->winheight = 0;
 
     sfree(randseed);
 
@@ -98,8 +130,11 @@ midend_data *midend_new(frontend *fe, const game *ourgame)
 
 static void midend_free_game(midend_data *me)
 {
-    while (me->nstates > 0)
-	me->ourgame->free_game(me->states[--me->nstates].state);
+    while (me->nstates > 0) {
+        me->nstates--;
+	me->ourgame->free_game(me->states[me->nstates].state);
+	sfree(me->states[me->nstates].movestr);
+    }
 
     if (me->drawstate)
         me->ourgame->free_drawstate(me->drawstate);
@@ -115,8 +150,7 @@ void midend_free(midend_data *me)
     sfree(me->states);
     sfree(me->desc);
     sfree(me->seedstr);
-    if (me->aux_info)
-	me->ourgame->free_aux_info(me->aux_info);
+    sfree(me->aux_info);
     me->ourgame->free_params(me->params);
     if (me->npresets) {
 	for (i = 0; i < me->npresets; i++) {
@@ -134,9 +168,11 @@ void midend_free(midend_data *me)
     sfree(me);
 }
 
-void midend_size(midend_data *me, int *x, int *y)
+void midend_size(midend_data *me, int *x, int *y, int expand)
 {
-    me->ourgame->size(me->params, x, y);
+    me->ourgame->size(me->params, me->drawstate, x, y, expand);
+    me->winwidth = *x;
+    me->winheight = *y;
 }
 
 void midend_set_params(midend_data *me, game_params *params)
@@ -155,11 +191,18 @@ static void midend_set_timer(midend_data *me)
 	deactivate_timer(me->frontend);
 }
 
+static void midend_size_new_drawstate(midend_data *me)
+{
+    me->ourgame->size(me->params, me->drawstate, &me->winwidth, &me->winheight,
+                      TRUE);
+}
+
 void midend_force_redraw(midend_data *me)
 {
     if (me->drawstate)
         me->ourgame->free_drawstate(me->drawstate);
     me->drawstate = me->ourgame->new_drawstate(me->states[0].state);
+    midend_size_new_drawstate(me);
     midend_redraw(me);
 }
 
@@ -200,23 +243,26 @@ void midend_new_game(midend_data *me)
         }
 
 	sfree(me->desc);
-	if (me->aux_info)
-	    me->ourgame->free_aux_info(me->aux_info);
+	sfree(me->privdesc);
+        sfree(me->aux_info);
 	me->aux_info = NULL;
 
         rs = random_init(me->seedstr, strlen(me->seedstr));
         me->desc = me->ourgame->new_desc(me->curparams, rs,
 					 &me->aux_info, TRUE);
+	me->privdesc = NULL;
         random_free(rs);
     }
 
     ensure(me);
     me->states[me->nstates].state =
 	me->ourgame->new_game(me, me->params, me->desc);
-    me->states[me->nstates].special = TRUE;
+    me->states[me->nstates].movestr = NULL;
+    me->states[me->nstates].movetype = NEWGAME;
     me->nstates++;
     me->statepos = 1;
     me->drawstate = me->ourgame->new_drawstate(me->states[0].state);
+    midend_size_new_drawstate(me);
     me->elapsed = 0.0F;
     midend_set_timer(me);
     if (me->ui)
@@ -228,6 +274,10 @@ void midend_new_game(midend_data *me)
 static int midend_undo(midend_data *me)
 {
     if (me->statepos > 1) {
+        if (me->ui)
+            me->ourgame->changed_state(me->ui,
+                                       me->states[me->statepos-1].state,
+                                       me->states[me->statepos-2].state);
 	me->statepos--;
         me->dir = -1;
         return 1;
@@ -238,6 +288,10 @@ static int midend_undo(midend_data *me)
 static int midend_redo(midend_data *me)
 {
     if (me->statepos < me->nstates) {
+        if (me->ui)
+            me->ourgame->changed_state(me->ui,
+                                       me->states[me->statepos-1].state,
+                                       me->states[me->statepos].state);
 	me->statepos++;
         me->dir = +1;
         return 1;
@@ -255,9 +309,9 @@ static void midend_finish_move(midend_data *me)
      * Restart moves.
      */
     if ((me->oldstate || me->statepos > 1) &&
-        ((me->dir > 0 && !me->states[me->statepos-1].special) ||
+        ((me->dir > 0 && !special(me->states[me->statepos-1].movetype)) ||
          (me->dir < 0 && me->statepos < me->nstates &&
-          !me->states[me->statepos].special))) {
+          !special(me->states[me->statepos].movetype)))) {
 	flashtime = me->ourgame->flash_length(me->oldstate ? me->oldstate :
 					      me->states[me->statepos-2].state,
 					      me->states[me->statepos-1].state,
@@ -296,7 +350,14 @@ void midend_restart_game(midend_data *me)
     if (me->statepos == 1)
         return;                        /* no point doing anything at all! */
 
-    s = me->ourgame->dup_game(me->states[0].state);
+    /*
+     * During restart, we reconstruct the game from the (public)
+     * game description rather than from states[0], because that
+     * way Mines gets slightly more sensible behaviour (restart
+     * goes to _after_ the first click so you don't have to
+     * remember where you clicked).
+     */
+    s = me->ourgame->new_game(me, me->params, me->desc);
 
     /*
      * Now enter the restarted state as the next move.
@@ -306,8 +367,13 @@ void midend_restart_game(midend_data *me)
 	me->ourgame->free_game(me->states[--me->nstates].state);
     ensure(me);
     me->states[me->nstates].state = s;
-    me->states[me->nstates].special = TRUE;   /* we just restarted */
+    me->states[me->nstates].movestr = dupstr(me->desc);
+    me->states[me->nstates].movetype = RESTART;
     me->statepos = ++me->nstates;
+    if (me->ui)
+        me->ourgame->changed_state(me->ui,
+                                   me->states[me->statepos-2].state,
+                                   me->states[me->statepos-1].state);
     me->anim_time = 0.0;
     midend_finish_move(me);
     midend_redraw(me);
@@ -329,7 +395,7 @@ static int midend_really_process_key(midend_data *me, int x, int y, int button)
     } else if (button == 'u' || button == 'u' ||
                button == '\x1A' || button == '\x1F') {
 	midend_stop_anim(me);
-        special = me->states[me->statepos-1].special;
+        special = special(me->states[me->statepos-1].movetype);
         gotspecial = TRUE;
 	if (!midend_undo(me))
 	    goto done;
@@ -342,9 +408,21 @@ static int midend_really_process_key(midend_data *me, int x, int y, int button)
 	ret = 0;
 	goto done;
     } else {
-        game_state *s =
-            me->ourgame->make_move(me->states[me->statepos-1].state,
-                                   me->ui, me->drawstate, x, y, button);
+        game_state *s;
+	char *movestr;
+	
+	movestr =
+            me->ourgame->interpret_move(me->states[me->statepos-1].state,
+					me->ui, me->drawstate, x, y, button);
+	if (!movestr)
+	    s = NULL;
+	else if (!*movestr)
+	    s = me->states[me->statepos-1].state;
+	else {
+	    s = me->ourgame->execute_move(me->states[me->statepos-1].state,
+					  movestr);
+	    assert(s != NULL);
+	}
 
         if (s == me->states[me->statepos-1].state) {
             /*
@@ -359,17 +437,19 @@ static int midend_really_process_key(midend_data *me, int x, int y, int button)
             while (me->nstates > me->statepos)
                 me->ourgame->free_game(me->states[--me->nstates].state);
             ensure(me);
+            assert(movestr != NULL);
             me->states[me->nstates].state = s;
-            me->states[me->nstates].special = FALSE;   /* normal move */
+            me->states[me->nstates].movestr = movestr;
+            me->states[me->nstates].movetype = MOVE;
             me->statepos = ++me->nstates;
             me->dir = +1;
         } else {
-          goto done;
+            goto done;
         }
     }
 
     if (!gotspecial)
-        special = me->states[me->statepos-1].special;
+        special = special(me->states[me->statepos-1].movetype);
 
     /*
      * See if this move requires an animation.
@@ -565,13 +645,12 @@ float *midend_colours(midend_data *me, int *ncolours)
     float *ret;
 
     if (me->nstates == 0) {
-	game_aux_info *aux = NULL;
+	char *aux = NULL;
         char *desc = me->ourgame->new_desc(me->params, me->random,
 					   &aux, TRUE);
         state = me->ourgame->new_game(me, me->params, desc);
         sfree(desc);
-	if (aux)
-	    me->ourgame->free_aux_info(aux);
+        sfree(aux);
     } else
         state = me->states[0].state;
 
@@ -699,10 +778,12 @@ int midend_wants_statusbar(midend_data *me)
     return me->ourgame->wants_statusbar();
 }
 
-void midend_supersede_game_desc(midend_data *me, char *desc)
+void midend_supersede_game_desc(midend_data *me, char *desc, char *privdesc)
 {
     sfree(me->desc);
+    sfree(me->privdesc);
     me->desc = dupstr(desc);
+    me->privdesc = privdesc ? dupstr(privdesc) : NULL;
 }
 
 config_item *midend_get_config(midend_data *me, int which, char **wintitle)
@@ -842,7 +923,8 @@ static char *midend_game_id_int(midend_data *me, char *id, int defmode)
     }
 
     sfree(me->desc);
-    me->desc = NULL;
+    sfree(me->privdesc);
+    me->desc = me->privdesc = NULL;
     sfree(me->seedstr);
     me->seedstr = NULL;
 
@@ -853,8 +935,7 @@ static char *midend_game_id_int(midend_data *me, char *id, int defmode)
 
         me->desc = dupstr(desc);
         me->genmode = GOT_DESC;
-	if (me->aux_info)
-	    me->ourgame->free_aux_info(me->aux_info);
+        sfree(me->aux_info);
 	me->aux_info = NULL;
     }
 
@@ -913,7 +994,7 @@ char *midend_text_format(midend_data *me)
 char *midend_solve(midend_data *me)
 {
     game_state *s;
-    char *msg;
+    char *msg, *movestr;
 
     if (!me->ourgame->can_solve)
 	return "This game does not support the Solve operation";
@@ -922,9 +1003,13 @@ char *midend_solve(midend_data *me)
 	return "No game set up to solve";   /* _shouldn't_ happen! */
 
     msg = "Solve operation failed";    /* game _should_ overwrite on error */
-    s = me->ourgame->solve(me->states[0].state, me->aux_info, &msg);
-    if (!s)
+    movestr = me->ourgame->solve(me->states[0].state,
+				 me->states[me->statepos-1].state,
+				 me->aux_info, &msg);
+    if (!movestr)
 	return msg;
+    s = me->ourgame->execute_move(me->states[me->statepos-1].state, movestr);
+    assert(s);
 
     /*
      * Now enter the solved state as the next move.
@@ -934,8 +1019,13 @@ char *midend_solve(midend_data *me)
 	me->ourgame->free_game(me->states[--me->nstates].state);
     ensure(me);
     me->states[me->nstates].state = s;
-    me->states[me->nstates].special = TRUE;   /* created using solve */
+    me->states[me->nstates].movestr = movestr;
+    me->states[me->nstates].movetype = SOLVE;
     me->statepos = ++me->nstates;
+    if (me->ui)
+        me->ourgame->changed_state(me->ui,
+                                   me->states[me->statepos-2].state,
+                                   me->states[me->statepos-1].state);
     me->anim_time = 0.0;
     midend_finish_move(me);
     midend_redraw(me);
@@ -972,3 +1062,487 @@ char *midend_rewrite_statusbar(midend_data *me, char *text)
 	return dupstr(text);
     }
 }
+
+#define SERIALISE_MAGIC "Simon Tatham's Portable Puzzle Collection"
+#define SERIALISE_VERSION "1"
+
+void midend_serialise(midend_data *me,
+                      void (*write)(void *ctx, void *buf, int len),
+                      void *wctx)
+{
+    int i;
+
+    /*
+     * Each line of the save file contains three components. First
+     * exactly 8 characters of header word indicating what type of
+     * data is contained on the line; then a colon followed by a
+     * decimal integer giving the length of the main string on the
+     * line; then a colon followed by the string itself (exactly as
+     * many bytes as previously specified, no matter what they
+     * contain). Then a newline (of reasonably flexible form).
+     */
+#define wr(h,s) do { \
+    char hbuf[80]; \
+    char *str = (s); \
+    sprintf(hbuf, "%-8.8s:%d:", (h), strlen(str)); \
+    write(wctx, hbuf, strlen(hbuf)); \
+    write(wctx, str, strlen(str)); \
+    write(wctx, "\n", 1); \
+} while (0)
+
+    /*
+     * Magic string identifying the file, and version number of the
+     * file format.
+     */
+    wr("SAVEFILE", SERIALISE_MAGIC);
+    wr("VERSION", SERIALISE_VERSION);
+
+    /*
+     * The game name. (Copied locally to avoid const annoyance.)
+     */
+    {
+        char *s = dupstr(me->ourgame->name);
+        wr("GAME", s);
+        sfree(s);
+    }
+
+    /*
+     * The current long-term parameters structure, in full.
+     */
+    if (me->params) {
+        char *s = me->ourgame->encode_params(me->params, TRUE);
+        wr("PARAMS", s);
+        sfree(s);
+    }
+
+    /*
+     * The current short-term parameters structure, in full.
+     */
+    if (me->curparams) {
+        char *s = me->ourgame->encode_params(me->curparams, TRUE);
+        wr("CPARAMS", s);
+        sfree(s);
+    }
+
+    /*
+     * The current game description, the privdesc, and the random seed.
+     */
+    if (me->seedstr)
+        wr("SEED", me->seedstr);
+    if (me->desc)
+        wr("DESC", me->desc);
+    if (me->privdesc)
+        wr("PRIVDESC", me->privdesc);
+
+    /*
+     * The game's aux_info. We obfuscate this to prevent spoilers
+     * (people are likely to run `head' or similar on a saved game
+     * file simply to find out what it is, and don't necessarily
+     * want to be told the answer to the puzzle!)
+     */
+    if (me->aux_info) {
+        unsigned char *s1;
+        char *s2;
+        int len;
+
+        len = strlen(me->aux_info);
+        s1 = snewn(len, unsigned char);
+        memcpy(s1, me->aux_info, len);
+        obfuscate_bitmap(s1, len*8, FALSE);
+        s2 = bin2hex(s1, len);
+
+        wr("AUXINFO", s2);
+
+        sfree(s2);
+        sfree(s1);
+    }
+
+    /*
+     * Any required serialisation of the game_ui.
+     */
+    if (me->ui) {
+        char *s = me->ourgame->encode_ui(me->ui);
+        if (s) {
+            wr("UI", s);
+            sfree(s);
+        }
+    }
+
+    /*
+     * The game time, if it's a timed game.
+     */
+    if (me->ourgame->is_timed) {
+        char buf[80];
+        sprintf(buf, "%g", me->elapsed);
+        wr("TIME", buf);
+    }
+
+    /*
+     * The length of, and position in, the states list.
+     */
+    {
+        char buf[80];
+        sprintf(buf, "%d", me->nstates);
+        wr("NSTATES", buf);
+        sprintf(buf, "%d", me->statepos);
+        wr("STATEPOS", buf);
+    }
+
+    /*
+     * For each state after the initial one (which we know is
+     * constructed from either privdesc or desc), enough
+     * information for execute_move() to reconstruct it from the
+     * previous one.
+     */
+    for (i = 1; i < me->nstates; i++) {
+        assert(me->states[i].movetype != NEWGAME);   /* only state 0 */
+        switch (me->states[i].movetype) {
+          case MOVE:
+            wr("MOVE", me->states[i].movestr);
+            break;
+          case SOLVE:
+            wr("SOLVE", me->states[i].movestr);
+            break;
+          case RESTART:
+            wr("RESTART", me->states[i].movestr);
+            break;
+        }
+    }
+
+#undef wr
+}
+
+/*
+ * This function returns NULL on success, or an error message.
+ */
+char *midend_deserialise(midend_data *me,
+                         int (*read)(void *ctx, void *buf, int len),
+                         void *rctx)
+{
+    int nstates = 0, statepos = -1, gotstates = 0;
+    int started = FALSE;
+    int i;
+
+    char *val = NULL;
+    /* Initially all errors give the same report */
+    char *ret = "Data does not appear to be a saved game file";
+
+    /*
+     * We construct all the new state in local variables while we
+     * check its sanity. Only once we have finished reading the
+     * serialised data and detected no errors at all do we start
+     * modifying stuff in the midend_data passed in.
+     */
+    char *seed = NULL, *parstr = NULL, *desc = NULL, *privdesc = NULL;
+    char *auxinfo = NULL, *uistr = NULL, *cparstr = NULL;
+    float elapsed = 0.0F;
+    game_params *params = NULL, *cparams = NULL;
+    game_ui *ui = NULL;
+    struct midend_state_entry *states = NULL;
+
+    /*
+     * Loop round and round reading one key/value pair at a time
+     * from the serialised stream, until we have enough game states
+     * to finish.
+     */
+    while (nstates <= 0 || statepos < 0 || gotstates < nstates-1) {
+        char key[9], c;
+        int len;
+
+        do {
+            if (!read(rctx, key, 1)) {
+                /* unexpected EOF */
+                goto cleanup;
+            }
+        } while (key[0] == '\r' || key[0] == '\n');
+
+        if (!read(rctx, key+1, 8)) {
+            /* unexpected EOF */
+            goto cleanup;
+        }
+
+        if (key[8] != ':') {
+            if (started)
+                ret = "Data was incorrectly formatted for a saved game file";
+        }
+        len = strcspn(key, ": ");
+        assert(len <= 8);
+        key[len] = '\0';
+
+        len = 0;
+        while (1) {
+            if (!read(rctx, &c, 1)) {
+                /* unexpected EOF */
+                goto cleanup;
+            }
+
+            if (c == ':') {
+                break;
+            } else if (c >= '0' && c <= '9') {
+                len = (len * 10) + (c - '0');
+            } else {
+                if (started)
+                    ret = "Data was incorrectly formatted for a"
+                    " saved game file";
+                goto cleanup;
+            }
+        }
+
+        val = snewn(len+1, char);
+        if (!read(rctx, val, len)) {
+            if (started)
+            goto cleanup;
+        }
+        val[len] = '\0';
+
+        if (!started) {
+            if (strcmp(key, "SAVEFILE") || strcmp(val, SERIALISE_MAGIC)) {
+                /* ret already has the right message in it */
+                goto cleanup;
+            }
+            /* Now most errors are this one, unless otherwise specified */
+            ret = "Saved data ended unexpectedly";
+            started = TRUE;
+        } else {
+            if (!strcmp(key, "VERSION")) {
+                if (strcmp(val, SERIALISE_VERSION)) {
+                    ret = "Cannot handle this version of the saved game"
+                        " file format";
+                    goto cleanup;
+                }
+            } else if (!strcmp(key, "GAME")) {
+                if (strcmp(val, me->ourgame->name)) {
+                    ret = "Save file is from a different game";
+                    goto cleanup;
+                }
+            } else if (!strcmp(key, "PARAMS")) {
+                sfree(parstr);
+                parstr = val;
+                val = NULL;
+            } else if (!strcmp(key, "CPARAMS")) {
+                sfree(cparstr);
+                cparstr = val;
+                val = NULL;
+            } else if (!strcmp(key, "SEED")) {
+                sfree(seed);
+                seed = val;
+                val = NULL;
+            } else if (!strcmp(key, "DESC")) {
+                sfree(desc);
+                desc = val;
+                val = NULL;
+            } else if (!strcmp(key, "PRIVDESC")) {
+                sfree(privdesc);
+                privdesc = val;
+                val = NULL;
+            } else if (!strcmp(key, "AUXINFO")) {
+                unsigned char *tmp;
+                int len = strlen(val) / 2;   /* length in bytes */
+                tmp = hex2bin(val, len);
+                obfuscate_bitmap(tmp, len*8, TRUE);
+
+                sfree(auxinfo);
+                auxinfo = snewn(len + 1, char);
+                memcpy(auxinfo, tmp, len);
+                auxinfo[len] = '\0';
+                sfree(tmp);
+            } else if (!strcmp(key, "UI")) {
+                sfree(uistr);
+                uistr = val;
+                val = NULL;
+            } else if (!strcmp(key, "TIME")) {
+                elapsed = strtod(val, NULL);
+            } else if (!strcmp(key, "NSTATES")) {
+                nstates = atoi(val);
+                if (nstates <= 0) {
+                    ret = "Number of states in save file was negative";
+                    goto cleanup;
+                }
+                if (states) {
+                    ret = "Two state counts provided in save file";
+                    goto cleanup;
+                }
+                states = snewn(nstates, struct midend_state_entry);
+                for (i = 0; i < nstates; i++) {
+                    states[i].state = NULL;
+                    states[i].movestr = NULL;
+                    states[i].movetype = NEWGAME;
+                }
+            } else if (!strcmp(key, "STATEPOS")) {
+                statepos = atoi(val);
+            } else if (!strcmp(key, "MOVE")) {
+                gotstates++;
+                states[gotstates].movetype = MOVE;
+                states[gotstates].movestr = val;
+                val = NULL;
+            } else if (!strcmp(key, "SOLVE")) {
+                gotstates++;
+                states[gotstates].movetype = SOLVE;
+                states[gotstates].movestr = val;
+                val = NULL;
+            } else if (!strcmp(key, "RESTART")) {
+                gotstates++;
+                states[gotstates].movetype = RESTART;
+                states[gotstates].movestr = val;
+                val = NULL;
+            }
+        }
+
+        sfree(val);
+        val = NULL;
+    }
+
+    params = me->ourgame->default_params();
+    me->ourgame->decode_params(params, parstr);
+    if (me->ourgame->validate_params(params)) {
+        ret = "Long-term parameters in save file are invalid";
+        goto cleanup;
+    }
+    cparams = me->ourgame->default_params();
+    me->ourgame->decode_params(cparams, cparstr);
+    if (me->ourgame->validate_params(cparams)) {
+        ret = "Short-term parameters in save file are invalid";
+        goto cleanup;
+    }
+    if (!desc) {
+        ret = "Game description in save file is missing";
+        goto cleanup;
+    } else if (me->ourgame->validate_desc(params, desc)) {
+        ret = "Game description in save file is invalid";
+        goto cleanup;
+    }
+    if (privdesc && me->ourgame->validate_desc(params, privdesc)) {
+        ret = "Game private description in save file is invalid";
+        goto cleanup;
+    }
+    if (statepos < 0 || statepos >= nstates) {
+        ret = "Game position in save file is out of range";
+    }
+
+    states[0].state = me->ourgame->new_game(me, params,
+                                            privdesc ? privdesc : desc);
+    for (i = 1; i < nstates; i++) {
+        assert(states[i].movetype != NEWGAME);
+        switch (states[i].movetype) {
+          case MOVE:
+          case SOLVE:
+            states[i].state = me->ourgame->execute_move(states[i-1].state,
+                                                        states[i].movestr);
+            if (states[i].state == NULL) {
+                ret = "Save file contained an invalid move";
+                goto cleanup;
+            }
+            break;
+          case RESTART:
+            if (me->ourgame->validate_desc(params, states[i].movestr)) {
+                ret = "Save file contained an invalid restart move";
+                goto cleanup;
+            }
+            states[i].state = me->ourgame->new_game(me, params,
+                                                    states[i].movestr);
+            break;
+        }
+    }
+
+    ui = me->ourgame->new_ui(states[0].state);
+    me->ourgame->decode_ui(ui, uistr);
+
+    /*
+     * Now we've run out of possible error conditions, so we're
+     * ready to start overwriting the real data in the current
+     * midend. We'll do this by swapping things with the local
+     * variables, so that the same cleanup code will free the old
+     * stuff.
+     */
+    {
+        char *tmp;
+
+        tmp = me->desc;
+        me->desc = desc;
+        desc = tmp;
+
+        tmp = me->privdesc;
+        me->privdesc = privdesc;
+        privdesc = tmp;
+
+        tmp = me->seedstr;
+        me->seedstr = seed;
+        seed = tmp;
+
+        tmp = me->aux_info;
+        me->aux_info = auxinfo;
+        auxinfo = tmp;
+    }
+
+    me->genmode = GOT_NOTHING;
+
+    me->statesize = nstates;
+    nstates = me->nstates;
+    me->nstates = me->statesize;
+    {
+        struct midend_state_entry *tmp;
+        tmp = me->states;
+        me->states = states;
+        states = tmp;
+    }
+    me->statepos = statepos;
+
+    {
+        game_params *tmp;
+
+        tmp = me->params;
+        me->params = params;
+        params = tmp;
+
+        tmp = me->curparams;
+        me->curparams = cparams;
+        cparams = tmp;
+    }
+
+    me->oldstate = NULL;
+    me->anim_time = me->anim_pos = me->flash_time = me->flash_pos = 0.0F;
+    me->dir = 0;
+
+    {
+        game_ui *tmp;
+
+        tmp = me->ui;
+        me->ui = ui;
+        ui = tmp;
+    }
+
+    me->elapsed = elapsed;
+    me->pressed_mouse_button = 0;
+
+    midend_set_timer(me);
+
+    ret = NULL;                        /* success! */
+
+    cleanup:
+    sfree(val);
+    sfree(seed);
+    sfree(parstr);
+    sfree(cparstr);
+    sfree(desc);
+    sfree(privdesc);
+    sfree(auxinfo);
+    sfree(uistr);
+    if (params)
+        me->ourgame->free_params(params);
+    if (cparams)
+        me->ourgame->free_params(cparams);
+    if (ui)
+        me->ourgame->free_ui(ui);
+    if (states) {
+        int i;
+
+        for (i = 0; i < nstates; i++) {
+            if (states[i].state)
+                me->ourgame->free_game(states[i].state);
+            sfree(states[i].movestr);
+        }
+        sfree(states);
+    }
+
+    return ret;
+}