Factor feels_like_helping() out of quiet_bigdef(), sd(), dd()

include/prototypes.h

@@ -437,6 +437,7 @@ extern void ef_fin_srv(void);
 extern int sd(natid, natid, coord, coord, int, int, int);
 extern int dd(natid, natid, coord, coord, int, int);
 extern int shipdef(natid, natid, coord, coord);
+extern int feels_like_helping(natid, natid, natid);
 /* getbit.c */
 extern int emp_getbit(int, int, unsigned char *);
 extern void emp_setbit(int, int, unsigned char *);

src/lib/commands/mfir.c

@@ -588,7 +588,7 @@ quiet_bigdef(int type, struct emp_qelem *list, natid own, natid aown,
     struct shpstr ship;
     struct lndstr land;
     struct nstr_item ni;
-    int dam, dam2, rel, rel2;
+    int dam, dam2;
     struct sctstr firing;
     struct nstr_sect ns;
     struct flist *fp;
@@ -598,19 +598,12 @@ quiet_bigdef(int type, struct emp_qelem *list, natid own, natid aown,
     dam = 0;
     snxtitem_dist(&ni, EF_SHIP, ax, ay, 8);
     while (nxtitem(&ni, &ship)) {
-	if (ship.shp_own == 0)
+	if (!feels_like_helping(ship.shp_own, own, aown))
 	    continue;
 
 	if ((mchr[ship.shp_type].m_flags & M_SUB) && type != EF_SHIP)
 	    continue;
 
-	rel = getrel(getnatp(ship.shp_own), own);
-	rel2 = getrel(getnatp(ship.shp_own), aown);
-	if ((ship.shp_own != own) && ((rel != ALLIED) || (rel2 != AT_WAR)))
-	    continue;
-	/* Don't shoot yourself */
-	if (ship.shp_own == aown)
-	    continue;
 	if (mchr[(int)ship.shp_type].m_flags & M_SUB) {
 	    erange = torprange(&ship);
 	    if (roundrange(erange) < ni.curdist)
@@ -650,16 +643,7 @@ quiet_bigdef(int type, struct emp_qelem *list, natid own, natid aown,
     }
     snxtitem_dist(&ni, EF_LAND, ax, ay, 8);
     while (nxtitem(&ni, &land)) {
-	if (land.lnd_own == 0)
+	if (!feels_like_helping(land.lnd_own, own, aown))
-	    continue;
-	/* Don't shoot yourself */
-	if (land.lnd_own == aown)
-	    continue;
-
-	rel = getrel(getnatp(land.lnd_own), own);
-	rel2 = getrel(getnatp(land.lnd_own), aown);
-
-	if ((land.lnd_own != own) && ((rel != ALLIED) || (rel2 != AT_WAR)))
 	    continue;
 
 	erange = lnd_fire_range(&land);
@@ -697,17 +681,9 @@ quiet_bigdef(int type, struct emp_qelem *list, natid own, natid aown,
     if (!opt_NO_FORT_FIRE) {
 	snxtsct_dist(&ns, ax, ay, 8);
 	while (nxtsct(&ns, &firing)) {
-	    if (firing.sct_own == 0)
+	    if (!feels_like_helping(firing.sct_own, own, aown))
 		continue;
-	    rel = getrel(getnatp(firing.sct_own), own);
-	    rel2 = getrel(getnatp(firing.sct_own), aown);
 
-	    if ((firing.sct_own != own) &&
-		((rel != ALLIED) || (rel2 != AT_WAR)))
-		continue;
-	    /* Don't shoot yourself */
-	    if (firing.sct_own == aown)
-		continue;
 	    erange = fortrange(&firing);
 	    if (roundrange(erange) < ns.curdist)
 		continue;

src/lib/subs/fortdef.c

@@ -71,7 +71,7 @@ sd(natid att, natid own, coord x, coord y, int noisy, int defending,
     double eff;
     struct shpstr ship;
     struct nstr_item ni;
-    int dam, rel, rel2;
+    int dam;
 
     if (own == 0)
 	return 0;
@@ -80,15 +80,9 @@ sd(natid att, natid own, coord x, coord y, int noisy, int defending,
     eff = 1.0;
     snxtitem_dist(&ni, EF_SHIP, x, y, 8);
     while (nxtitem(&ni, &ship) && eff > 0.30) {
-	if (ship.shp_own == att)
+	if (!feels_like_helping(ship.shp_own, own, att))
-	    continue;
-	if (ship.shp_own == 0)
 	    continue;
 
-	rel = getrel(getnatp(ship.shp_own), own);
-	rel2 = getrel(getnatp(ship.shp_own), att);
-	if ((ship.shp_own != own) && ((rel != ALLIED) || (rel2 != AT_WAR)))
-	    continue;
 	if ((mchr[(int)ship.shp_type].m_flags & M_SUB) && !usesubs)
 	    continue;
 	range = roundrange(shp_fire_range(&ship));
@@ -131,7 +125,7 @@ sd(natid att, natid own, coord x, coord y, int noisy, int defending,
 int
 dd(natid att, natid def_own, coord ax, coord ay, int noisy, int defending)
 {
-    int dam, rel, rel2;
+    int dam;
     struct sctstr firing;
     struct nstr_sect ns;
 
@@ -144,13 +138,7 @@ dd(natid att, natid def_own, coord ax, coord ay, int noisy, int defending)
     dam = 0;
     snxtsct_dist(&ns, ax, ay, 8);
     while (nxtsct(&ns, &firing) && dam < 80) {
-	if (firing.sct_own == att)
+	if (!feels_like_helping(firing.sct_own, def_own, att))
-	    continue;
-	if (firing.sct_own == 0)
-	    continue;
-	rel = getrel(getnatp(firing.sct_own), def_own);
-	rel2 = getrel(getnatp(firing.sct_own), att);
-	if (firing.sct_own != def_own && (rel != ALLIED || rel2 != AT_WAR))
 	    continue;
 	/* XXX defdef damage is additive, but ship or land unit damage isn't */
 	dam += sb(att, def_own, &firing, ax, ay, noisy, defending);
@@ -158,6 +146,23 @@ dd(natid att, natid def_own, coord ax, coord ay, int noisy, int defending)
     return dam;
 }
 
+/*
+ * Shall CN attempt to help FRIEND against FOE?
+ */
+int
+feels_like_helping(natid cn, natid friend, natid foe)
+{
+    if (cn == 0)
+	return 0;		/* never helps anybody */
+    if (cn == foe)
+	return 0;		/* don't help anybody against self */
+    if (cn == friend)
+	return 1;		/* help self against anybody else */
+    /* third party helps ally if at war with foe: */
+    return getrel(getnatp(cn), friend) == ALLIED
+	&& getrel(getnatp(cn), foe) == AT_WAR;
+}
+
 /* Shoot back
  *
  * See if the sector being fired at will defend itself.