The Windows RNG turns out to only give about 16 bits at a time. This

[sgt-puzzles.git] / fifteen.c

diff --git a/fifteen.c b/fifteen.c
index 04a8f759a2ec5f6c87d70ab3c4ac92d5b82f1c53..3965844da94baf8909d90101d12a44cd84a2d7c5 100644 (file)
--- a/fifteen.c
+++ b/fifteen.c
@@ -131,7 +131,7 @@ int perm_parity(int *perm, int n)
     return ret;
 }
 
-char *new_game_seed(game_params *params)
+char *new_game_seed(game_params *params, random_state *rs)
 {
     int gap, n, i, x;
     int x1, x2, p1, p2, parity;
@@ -149,7 +149,7 @@ char *new_game_seed(game_params *params)
         used[i] = FALSE;
     }
 
-    gap = rand_upto(n);
+    gap = random_upto(rs, n);
     tiles[gap] = 0;
     used[0] = TRUE;
 
@@ -157,7 +157,7 @@ char *new_game_seed(game_params *params)
      * Place everything else except the last two tiles.
      */
     for (x = 0, i = n-1; i > 2; i--) {
-        int k = rand_upto(i);
+        int k = random_upto(rs, i);
         int j;
 
         for (j = 0; j < n; j++)
@@ -246,6 +246,57 @@ char *new_game_seed(game_params *params)
     return ret;
 }
 
+char *validate_seed(game_params *params, char *seed)
+{
+    char *p, *err;
+    int i, area;
+    int *used;
+
+    area = params->w * params->h;
+    p = seed;
+    err = NULL;
+
+    used = snewn(area, int);
+    for (i = 0; i < area; i++)
+       used[i] = FALSE;
+
+    for (i = 0; i < area; i++) {
+       char *q = p;
+       int n;
+
+       if (*p < '0' || *p > '9') {
+           err = "Not enough numbers in string";
+           goto leave;
+       }
+       while (*p >= '0' && *p <= '9')
+           p++;
+       if (i < area-1 && *p != ',') {
+           err = "Expected comma after number";
+           goto leave;
+       }
+       else if (i == area-1 && *p) {
+           err = "Excess junk at end of string";
+           goto leave;
+       }
+       n = atoi(q);
+       if (n < 0 || n >= area) {
+           err = "Number out of range";
+           goto leave;
+       }
+       if (used[n]) {
+           err = "Number used twice";
+           goto leave;
+       }
+       used[n] = TRUE;
+
+       if (*p) p++;                   /* eat comma */
+    }
+
+    leave:
+    sfree(used);
+    return err;
+}
+
 game_state *new_game(game_params *params, char *seed)
 {
     game_state *state = snew(game_state);