+static game_params *dup_params(game_params *params)
+{
+ game_params *ret = snew(game_params);
+ *ret = *params; /* structure copy */
+ return ret;
+}
+
+static game_params *decode_params(char const *string)
+{
+ game_params *ret = default_params();
+ char const *p = string;
+
+ ret->width = atoi(p);
+ while (*p && isdigit(*p)) p++;
+ if (*p == 'x') {
+ p++;
+ ret->height = atoi(p);
+ while (*p && isdigit(*p)) p++;
+ if ( (ret->wrapping = (*p == 'w')) != 0 )
+ p++;
+ if (*p == 'b')
+ ret->barrier_probability = atof(p+1);
+ } else {
+ ret->height = ret->width;
+ }
+
+ return ret;
+}
+
+static char *encode_params(game_params *params)
+{
+ char ret[400];
+ int len;
+
+ len = sprintf(ret, "%dx%d", params->width, params->height);
+ if (params->wrapping)
+ ret[len++] = 'w';
+ if (params->barrier_probability)
+ len += sprintf(ret+len, "b%g", params->barrier_probability);
+ assert(len < lenof(ret));
+ ret[len] = '\0';
+
+ return dupstr(ret);
+}
+
+static config_item *game_configure(game_params *params)
+{
+ config_item *ret;
+ char buf[80];
+
+ ret = snewn(5, config_item);
+
+ ret[0].name = "Width";
+ ret[0].type = C_STRING;
+ sprintf(buf, "%d", params->width);
+ ret[0].sval = dupstr(buf);
+ ret[0].ival = 0;
+
+ ret[1].name = "Height";
+ ret[1].type = C_STRING;
+ sprintf(buf, "%d", params->height);
+ ret[1].sval = dupstr(buf);
+ ret[1].ival = 0;
+
+ ret[2].name = "Walls wrap around";
+ ret[2].type = C_BOOLEAN;
+ ret[2].sval = NULL;
+ ret[2].ival = params->wrapping;
+
+ ret[3].name = "Barrier probability";
+ ret[3].type = C_STRING;
+ sprintf(buf, "%g", params->barrier_probability);
+ ret[3].sval = dupstr(buf);
+ ret[3].ival = 0;
+
+ ret[4].name = NULL;
+ ret[4].type = C_END;
+ ret[4].sval = NULL;
+ ret[4].ival = 0;
+
+ return ret;
+}
+
+static game_params *custom_params(config_item *cfg)
+{
+ game_params *ret = snew(game_params);
+
+ ret->width = atoi(cfg[0].sval);
+ ret->height = atoi(cfg[1].sval);
+ ret->wrapping = cfg[2].ival;
+ ret->barrier_probability = (float)atof(cfg[3].sval);
+
+ return ret;
+}
+
+static char *validate_params(game_params *params)
+{
+ if (params->width <= 0 && params->height <= 0)
+ return "Width and height must both be greater than zero";
+ if (params->width <= 0)
+ return "Width must be greater than zero";
+ if (params->height <= 0)
+ return "Height must be greater than zero";
+ if (params->width <= 1 && params->height <= 1)
+ return "At least one of width and height must be greater than one";
+ if (params->barrier_probability < 0)
+ return "Barrier probability may not be negative";
+ if (params->barrier_probability > 1)
+ return "Barrier probability may not be greater than 1";
+ return NULL;
+}
+