(s_commod): Clarify and comment the trickery required to make the

recursion work.  By the way, resuppling from supply units in unit id
order is a greedy algorithm, which is quite inappropriate for the
problem.

diff --git a/src/lib/subs/supply.c b/src/lib/subs/supply.c
index 514c7eb2d84f13af4ce6f81f71feffa9c889c1e3..34d4b1490d5d2b4aab2f87b1df4b3e9ba7e6080b 100644 (file)
--- a/src/lib/subs/supply.c
+++ b/src/lib/subs/supply.c
@@ -390,22 +390,28 @@ s_commod(int own, int x, int y, int type, int total_wanted,
 
        if ((vec[type] - wanted) < get_minimum(&land, type)) {
            int hold;
-           struct lndstr l2;
+           struct lndstr save;
 
-           l2 = land;
+           /*
+            * Temporarily zap this unit's store, so the recursion
+            * avoids it.
+            */
+           save = land;
            hold = vec[type];
            vec[type] = 0;
            putvec(VT_ITEM, vec, (s_char *)&land, EF_LAND);
            land.lnd_fuel = 0;
            putland(land.lnd_uid, &land);
-           hold +=
-               s_commod(own, land.lnd_x, land.lnd_y, type, wanted,
-                        actually_doit);
+
+           hold += s_commod(own, land.lnd_x, land.lnd_y, type, wanted,
+                            actually_doit);
+
            vec[type] = hold;
-           putvec(VT_ITEM, vec, (s_char *)&land, EF_LAND);
-           putland(land.lnd_uid, &land);
-           if (!actually_doit)
-               putland(l2.lnd_uid, &l2);
+           if (actually_doit) {
+               putvec(VT_ITEM, vec, (s_char *)&land, EF_LAND);
+               putland(land.lnd_uid, &land);
+           } else
+               putland(save.lnd_uid, &save);
        }
 
        getvec(VT_ITEM, vec, (s_char *)&land, EF_LAND);