[Freeciv-Dev] Re: Reproducable core dump (PR#1051)

[Petr Baudis <pasky@xxxxxxxxxxx>]

> Index: server/gotohand.c
> ===================================================================
> RCS file: /home/freeciv/CVS/freeciv/server/gotohand.c,v
> retrieving revision 1.122
> diff -u -r1.122 gotohand.c
> --- server/gotohand.c 2001/10/08 12:11:17     1.122
> +++ server/gotohand.c 2001/11/30 20:12:27
> @@ -38,6 +38,15 @@
>  /* These are used for airplane GOTOs with waypoints */
>  #define MAXFUEL 100
>  
> +/* These should be either true or false.  They are used for finding routes
> +    for airplanes - the airplane doesn't want to fly through occupied
> +    territory, but most territory will be either fogged or unknown entirely.
> +    See airspace_looks_usable().  Note that this is currently only used
> +    by the move-counting function air_can_move_between(), not by
> +    the path-finding function (whatever that may be). */
This comment's format looks odd. But never mind ;-).
> +#define AIR_ASSUMES_UNKNOWN_SAFE     TRUE
> +#define AIR_ASSUMES_FOGGED_SAFE      TRUE
> +
>  enum refuel_type {
>    FUEL_START = 0, FUEL_GOAL, FUEL_CITY, FUEL_AIRBASE
>  };
> @@ -1429,6 +1438,38 @@
>  }
>  
>  /**************************************************************************
> + Returns true if the given map position has airspace that _looks_
> + usable to the player.  The airspace is unusable if the player
> + believes there is an enemy unit on it.  This is tricky, since we have to
> + consider what the player knows/doesn't know.
> +**************************************************************************/
> +int airspace_looks_usable(int x, int y, struct player *pplayer)
> +{
> +  struct tile * ptile = map_get_tile(x, y);
> +
> +  /* If the tile's unknown, we (may) assume it's empty. */
> +  if (ai_handicap(pplayer, H_MAP) &&
This is odd. If pplayer is not AI, ai_handicap() will return -1, which is
nonzero so it will always return AIR_ASSUMES_UNKNOWN_SAFE for human players.
If it's an intent, it should be stated some comment clearly, otherwise you
should first test if the player is AI-controlled.
> +       !map_get_known(x, y, pplayer)) {
> +    return AIR_ASSUMES_UNKNOWN_SAFE;
> +  }
> +
> +  /* This is bad: there could be a city there that the player doesn't
> +      know about.  How can we check that? */
> +  if (is_non_allied_city_tile(ptile, pplayer)) {
> +    return 0;
> +  }
> +
> +  /* If the tile's fogged we again (may) assume it's empty. */
> +  if (ai_handicap(pplayer, H_FOG) &&
Again.
> +      !map_get_known_and_seen(x, y, pplayer)) {
> +    return AIR_ASSUMES_FOGGED_SAFE;
> +  }
> +
> +  /* Finally, we check to see if there's an enemy unit on the tile. */
> +  return !is_non_allied_unit_tile(ptile, pplayer);
> +}
> +
> +/**************************************************************************
>   Returns #moves left when player playerid is moving a unit from src_x,src_y 
> to
>   dest_x,dest_y in moves moves. [Kero]
>   If there was no way to move between returns -1.

-- 

                                Petr "Pasky" Baudis

UN*X programmer, UN*X administrator, hobbies = IPv6, IRC, FreeCiv hacking
.
  "A common mistake that people make, when trying to design
   something completely foolproof is to underestimate the
   ingenuity of complete fools."
     -- Douglas Adams in Mostly Harmless
.
Public PGP key, geekcode and stuff: http://pasky.ji.cz/~pasky/