From d5afd757a948ea2281cea06078fbc55405cfaa82 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@pond.sub.org>
Date: Sun, 4 Nov 2007 15:07:43 +0000
Subject: [PATCH] (carrier_planes): New. (pln_onewaymission): Use it.  No
 functional change. (pln_airbase_ok): Use it to enforce capabilities.  Before,
 a plane could fly once it got on the ship.  Because ships can load only
 planes that can fly from them, this has no effect other than make that sanity
 check redundant; remove it.

(pln_airbase_ok): Update land unit case to keep it similar to the ship
case.
---
 src/lib/subs/plnsub.c | 54 +++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 22 deletions(-)

diff --git a/src/lib/subs/plnsub.c b/src/lib/subs/plnsub.c
index c7a6a047..76b51407 100644
--- a/src/lib/subs/plnsub.c
+++ b/src/lib/subs/plnsub.c
@@ -55,6 +55,7 @@
 #include "ship.h"
 #include "xy.h"
 
+static int carrier_planes(struct shpstr *);
 static int pln_equip(struct plist *, struct ichrstr *, int, char);
 static int fit_plane_on_ship(struct plnstr *, struct shpstr *);
 
@@ -104,7 +105,7 @@ pln_onewaymission(struct sctstr *target, int *shipno, int *flagp)
 {
     int nships;
     int cno;
-    int flags;
+    int flags, fl;
     struct shpstr ship;
     char buf[1024];
     char *p;
@@ -132,22 +133,14 @@ pln_onewaymission(struct sctstr *target, int *shipno, int *flagp)
 		   xyas(target->sct_x, target->sct_y, player->cnum));
 		continue;
 	    }
-	    if ((!(mchr[(int)ship.shp_type].m_flags & M_FLY)
-		 && !(mchr[(int)ship.shp_type].m_flags & M_XLIGHT)
-		 && !(mchr[(int)ship.shp_type].m_flags & M_CHOPPER))
-		|| ship.shp_effic < SHP_AIROPS_EFF) {
+	    fl = carrier_planes(&ship);
+	    if (fl == 0) {
 		pr("Can't land on %s.\n", prship(&ship));
 		continue;
 	    }
-
 	    /* clear to land on ship#CNO */
 	    pr("landing on carrier %d\n", cno);
-	    if (mchr[(int)ship.shp_type].m_flags & M_FLY)
-		flags |= P_L;
-	    if (mchr[(int)ship.shp_type].m_flags & M_CHOPPER)
-		flags |= P_K;
-	    if (mchr[(int)ship.shp_type].m_flags & M_XLIGHT)
-		flags |= P_E;
+	    flags |= fl;
 	    *shipno = cno;
 	    *flagp = flags;
 	    return 0;
@@ -385,6 +378,31 @@ pln_capable(struct plnstr *pp, int wantflags, int nowantflags)
     return 1;
 }
 
+/*
+ * Find non-missile plane types that can operate from carrier SP.
+ * Return a combination of P_L, P_K, P_E.
+ * It's zero if SP can't support air operations due to its type or
+ * state (low efficiency).
+ */
+static int
+carrier_planes(struct shpstr *sp)
+{
+    struct mchrstr *mcp = mchr + sp->shp_type;
+    int res;
+
+    if (sp->shp_effic < SHP_AIROPS_EFF)
+	return 0;
+
+    res = 0;
+    if (mcp->m_flags & M_FLY)
+	res |= P_L;
+    if (mcp->m_flags & M_CHOPPER)
+	res |= P_K;
+    if (mcp->m_flags & M_XLIGHT)
+	res |= P_E;
+    return res;
+}
+
 int
 pln_airbase_ok(struct plnstr *pp, int oneway, int noisy)
 {
@@ -402,10 +420,6 @@ pln_airbase_ok(struct plnstr *pp, int oneway, int noisy)
 	    CANT_REACH();
 	    return 0;
 	}
-	if (CANT_HAPPEN(ship.shp_effic < SHIP_MINEFF
-			|| !could_be_on_ship(pp, &ship)))
-	    return 0;
-
 	if (ship.shp_own != pp->pln_own
 	    && getrel(getnatp(ship.shp_own), pp->pln_own) != ALLIED) {
 	    if (noisy)
@@ -413,7 +427,7 @@ pln_airbase_ok(struct plnstr *pp, int oneway, int noisy)
 		   prplane(pp));
 	    return 0;
 	}
-	if (ship.shp_effic < SHP_AIROPS_EFF)
+	if ((carrier_planes(&ship) & pcp->pl_flags) == 0)
 	    return 0;
 
     } else if (pp->pln_land >= 0) {
@@ -422,10 +436,6 @@ pln_airbase_ok(struct plnstr *pp, int oneway, int noisy)
 	    CANT_REACH();
 	    return 0;
 	}
-	if (CANT_HAPPEN(land.lnd_effic < LAND_MINEFF
-			|| !(pcp->pl_flags & P_E)))
-	    return 0;
-
 	if (land.lnd_own != pp->pln_own
 	    && getrel(getnatp(land.lnd_own), pp->pln_own) != ALLIED) {
 	    if (noisy)
@@ -433,7 +443,7 @@ pln_airbase_ok(struct plnstr *pp, int oneway, int noisy)
 		   prplane(pp));
 	    return 0;
 	}
-	if (land.lnd_effic < LND_AIROPS_EFF)
+	if (land.lnd_effic < LND_AIROPS_EFF || !(pcp->pl_flags & P_E))
 	    return 0;
 	if (land.lnd_ship >= 0 || land.lnd_land >= 0)
 	    return 0;