X-Git-Url: http://git.pond.sub.org/?p=empserver;a=blobdiff_plain;f=src%2Flib%2Fsubs%2Flndsub.c;h=2dd7f388252e58b0917d4d5006f7f6b91b19b7bc;hp=e789009e0734ac20130cf7250eca5d42d1527ef7;hb=beedf8dce;hpb=52a40481cb93d3fa8359df7a43fc2583308b42e0

diff --git a/src/lib/subs/lndsub.c b/src/lib/subs/lndsub.c
index e789009e0..2dd7f3882 100644
--- a/src/lib/subs/lndsub.c
+++ b/src/lib/subs/lndsub.c
@@ -1,6 +1,6 @@
 /*
  *  Empire - A multi-player, client/server Internet based war game.
- *  Copyright (C) 1986-2014, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *  Copyright (C) 1986-2015, Dave Pare, Jeff Bailey, Thomas Ruschak,
  *                Ken Stevens, Steve McClure, Markus Armbruster
  *
  *  Empire is free software: you can redistribute it and/or modify
@@ -29,7 +29,7 @@
  *  Known contributors to this file:
  *     Ken Stevens, 1995
  *     Steve McClure, 1998-2000
- *     Markus Armbruster, 2004-2012
+ *     Markus Armbruster, 2004-2015
  */
 
 #include <config.h>
@@ -52,10 +52,25 @@
 #include "unit.h"
 #include "xy.h"
 
-static void lnd_stays(natid, char *, struct ulist *);
+static void lnd_mar_put_one(struct ulist *);
+static int lnd_check_one_mines(struct ulist *, int);
 static int lnd_hit_mine(struct lndstr *);
 static int has_helpful_engineer(coord, coord, natid);
 
+static struct ulist *
+lnd_find_capable(struct emp_qelem *list, int flags)
+{
+    struct emp_qelem *qp;
+    struct ulist *llp;
+
+    for (qp = list->q_back; qp != list; qp = qp->q_back) {
+	llp = (struct ulist *)qp;
+	if (lchr[llp->unit.land.lnd_type].l_flags & flags)
+	    return llp;
+    }
+    return NULL;
+}
+
 double
 attack_val(int combat_mode, struct lndstr *lp)
 {
@@ -145,14 +160,6 @@ lnd_print(natid actor, struct ulist *llp, char *s)
 	wu(0, actor, "%s %s\n", prland(&llp->unit.land), s);
 }
 
-void
-lnd_delete(struct ulist *llp)
-{
-    putland(llp->unit.land.lnd_uid, &llp->unit.land);
-    emp_remque(&llp->queue);
-    free(llp);
-}
-
 int
 lnd_take_casualty(int combat_mode, struct ulist *llp, int cas)
 			/* attacking or assaulting or paratrooping? */
@@ -175,11 +182,11 @@ lnd_take_casualty(int combat_mode, struct ulist *llp, int cas)
 
     taken = llp->unit.land.lnd_item[I_MILIT];
     /* Spies always die */
-    if (((struct lchrstr *)llp->chrp)->l_flags & L_SPY)
+    if (lchr[llp->unit.land.lnd_type].l_flags & L_SPY)
 	llp->unit.land.lnd_effic = 0;
     else {
 	eff_eq = ldround(cas * 100.0 /
-	    ((struct lchrstr *)llp->chrp)->l_item[I_MILIT], 1);
+	    lchr[llp->unit.land.lnd_type].l_item[I_MILIT], 1);
 	llp->unit.land.lnd_effic -= eff_eq;
 	lnd_submil(&llp->unit.land, cas);
     }
@@ -190,7 +197,7 @@ lnd_take_casualty(int combat_mode, struct ulist *llp, int cas)
 		xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y,
 		     llp->unit.land.lnd_own));
 	lnd_print(llp->unit.land.lnd_own, llp, buf);
-	lnd_delete(llp);
+	lnd_put_one(llp);
 	/* Since we killed the unit, we killed all the mil on it */
 	return taken;
     } else {
@@ -264,7 +271,7 @@ lnd_take_casualty(int combat_mode, struct ulist *llp, int cas)
 			llp->unit.land.lnd_effic,
 			xyas(bx, by, llp->unit.land.lnd_own));
 		lnd_print(llp->unit.land.lnd_own, llp, buf);
-		lnd_delete(llp);
+		lnd_put_one(llp);
 	    }
 	} else {		/* attacking from a sector */
 	    sprintf(buf, "leaves the battlefield at %d%% efficiency",
@@ -275,18 +282,18 @@ lnd_take_casualty(int combat_mode, struct ulist *llp, int cas)
 		llp->unit.land.lnd_mobil -= (int)llp->mobil;
 	    llp->mobil = 0.0;
 	    lnd_print(llp->unit.land.lnd_own, llp, buf);
-	    lnd_delete(llp);
+	    lnd_put_one(llp);
 	}
     }
     if (nowhere_to_go) {
 	/* nowhere to go.. take more casualties */
 	llp->unit.land.lnd_effic -= 10;
 	lnd_submil(&llp->unit.land,
-		   ((struct lchrstr *)llp->chrp)->l_item[I_MILIT] / 10);
+		   lchr[llp->unit.land.lnd_type].l_item[I_MILIT] / 10);
 	if (llp->unit.land.lnd_effic < LAND_MINEFF) {
 	    lnd_print(llp->unit.land.lnd_own, llp,
 		      "has nowhere to retreat, and dies!");
-	    lnd_delete(llp);
+	    lnd_put_one(llp);
 	} else
 	    lnd_print(llp->unit.land.lnd_own, llp,
 		      "has nowhere to retreat and takes extra losses!");
@@ -392,14 +399,95 @@ intelligence_report(int destination, struct lndstr *lp, int spy,
     }
 }
 
+int
+lnd_may_mar(struct lndstr *lp, struct lndstr *ldr, char *suffix)
+{
+    struct sctstr sect;
+    int mobtype;
+
+    if (!lp->lnd_own || !getsect(lp->lnd_x, lp->lnd_y, &sect)) {
+	CANT_REACH();
+	return 0;
+    }
+
+    if (opt_MARKET && ontradingblock(EF_LAND, lp)) {
+	mpr(lp->lnd_own, "%s is on the trading block%s\n",
+	    prland(lp), suffix);
+	return 0;
+    }
+
+    if (lp->lnd_ship >= 0) {
+	mpr(lp->lnd_own, "%s is on a ship%s\n", prland(lp), suffix);
+	return 0;
+    }
+    if (lp->lnd_land >= 0) {
+	mpr(lp->lnd_own, "%s is on a unit%s\n", prland(lp), suffix);
+	return 0;
+    }
+
+    if (!(lchr[lp->lnd_type].l_flags & L_SPY) &&
+	!(lchr[lp->lnd_type].l_flags & L_TRAIN) &&
+	lp->lnd_item[I_MILIT] == 0) {
+	mpr(lp->lnd_own, "%s has no mil on it to guide it%s\n",
+	    prland(lp), suffix);
+	return 0;
+    }
+
+    switch (lnd_check_mar(lp, &sect)) {
+    case LND_STUCK_NOT:
+	break;
+    case LND_STUCK_NO_RAIL:
+	mpr(lp->lnd_own, "%s is stuck off the rail system%s\n",
+	    prland(lp), suffix);
+	return 0;
+    default:
+	CANT_REACH();
+	/* fall through */
+    case LND_STUCK_IMPASSABLE:
+	mpr(lp->lnd_own, "%s is stuck%s\n", prland(lp), suffix);
+	return 0;
+    }
+
+    if (relations_with(sect.sct_own, lp->lnd_own) != ALLIED &&
+	!(lchr[lp->lnd_type].l_flags & L_SPY) &&
+	sect.sct_own) {
+	mpr(lp->lnd_own, "%s has been kidnapped by %s%s\n",
+	    prland(lp), cname(sect.sct_own), suffix);
+	return 0;
+    }
+
+    if (ldr && (lp->lnd_x != ldr->lnd_x || lp->lnd_y != ldr->lnd_y)) {
+	mpr(lp->lnd_own, "%s is not with the leader%s\n",
+	    prland(lp), suffix);
+	return 0;
+    }
+
+    /*
+     * The marching code gets confused when trains and non-trains
+     * march together.  Disallow for now.
+     */
+    mobtype = lnd_mobtype(lp);
+    if (!ldr || mobtype == lnd_mobtype(ldr))
+	;
+    else if (mobtype == MOB_RAIL) {
+	mpr(lp->lnd_own,
+	    "%s is a train and can't march with the leader%s\n",
+	    prland(lp), suffix);
+	return 0;
+    } else {
+	mpr(lp->lnd_own, "%s can't rail-march with the leading train%s\n",
+	    prland(lp), suffix);
+	return 0;
+    }
+
+    return 1;
+}
+
 void
 lnd_sel(struct nstr_item *ni, struct emp_qelem *list)
 {
-    struct lndstr land;
-    struct lchrstr *lcp;
+    struct lndstr land, *ldr = NULL;
     struct ulist *llp;
-    int this_mot;
-    int mobtype = MOB_MOVE;	/* indeterminate */
 
     emp_initque(list);
     while (nxtitem(ni, &land)) {
@@ -410,69 +498,49 @@ lnd_sel(struct nstr_item *ni, struct emp_qelem *list)
 	 */
 	if (!land.lnd_own || land.lnd_own != player->cnum)
 	    continue;
-	if (opt_MARKET) {
-	    if (ontradingblock(EF_LAND, &land)) {
-		pr("unit #%d inelligible - it's for sale.\n",
-		   land.lnd_uid);
-		continue;
-	    }
-	}
-	/*
-	 * The marching code gets confused when trains and non-trains
-	 * march together.  Disallow for now.
-	 */
-	this_mot = lnd_mobtype(&land);
-	if (this_mot != mobtype) {
-	    if (mobtype == MOB_MOVE)
-		mobtype = this_mot;
-	    else if (mobtype == MOB_MARCH) {
-		pr("%s is a train and can't march with the leader.\n",
-		   prland(&land));
-		continue;
-	    } else {
-		pr("%s can't rail-march with the leading train.\n",
-		   prland(&land));
-		continue;
-	    }
-	}
+	if (!lnd_may_mar(&land, ldr, ""))
+	    continue;
 
-	lcp = &lchr[(int)land.lnd_type];
 	land.lnd_mission = 0;
 	land.lnd_rflags = 0;
-	land.lnd_harden = 0;
 	memset(land.lnd_rpath, 0, sizeof(land.lnd_rpath));
 	putland(land.lnd_uid, &land);
-	llp = malloc(sizeof(struct ulist));
-	llp->chrp = (struct empobj_chr *)lcp;
-	llp->unit.land = land;
-	llp->mobil = land.lnd_mobil;
-	emp_insque(&llp->queue, list);
+	llp = lnd_insque(&land, list);
+	if (!ldr)
+	    ldr = &llp->unit.land;
     }
 }
 
-/* This function assumes that the list was created by lnd_sel */
+/*
+ * Append LP to LIST.
+ * Return the new list link.
+ */
+struct ulist *
+lnd_insque(struct lndstr *lp, struct emp_qelem *list)
+{
+    struct ulist *mlp = malloc(sizeof(struct ulist));
+
+    mlp->unit.land = *lp;
+    mlp->mobil = lp->lnd_mobil;
+    emp_insque(&mlp->queue, list);
+    return mlp;
+}
+
 void
-lnd_mar(struct emp_qelem *list, double *minmobp, double *maxmobp,
-	int *togetherp, natid actor)
+lnd_mar_stay_behind(struct emp_qelem *list, natid actor)
 {
     struct emp_qelem *qp;
     struct emp_qelem *next;
     struct ulist *llp;
-    struct lndstr *lp;
-    struct sctstr sect;
-    coord allx;
-    coord ally;
-    int first = 1;
-    char mess[128];
-
-    *minmobp = 9876.0;
-    *maxmobp = -9876.0;
-    *togetherp = 1;
+    struct lndstr *lp, *ldr = NULL;
+    char and_stays[32];
+
     for (qp = list->q_back; qp != list; qp = next) {
 	next = qp->q_back;
 	llp = (struct ulist *)qp;
 	lp = &llp->unit.land;
 	getland(lp->lnd_uid, lp);
+
 	if (lp->lnd_own != actor) {
 	    mpr(actor, "%s was disbanded at %s\n",
 		prland(lp), xyas(lp->lnd_x, lp->lnd_y, actor));
@@ -480,55 +548,76 @@ lnd_mar(struct emp_qelem *list, double *minmobp, double *maxmobp,
 	    free(llp);
 	    continue;
 	}
-	if (lp->lnd_ship >= 0) {
-	    lnd_stays(actor, "is on a ship", llp);
-	    continue;
-	}
-	if (lp->lnd_land >= 0) {
-	    lnd_stays(actor, "is on a unit", llp);
-	    continue;
-	}
-	if (!getsect(lp->lnd_x, lp->lnd_y, &sect)) {
-	    lnd_stays(actor, "was sucked into the sky by a strange looking spaceland", llp);	/* heh -KHS */
-	    continue;
-	}
-	if (!(lchr[lp->lnd_type].l_flags & L_SPY) &&
-	    !(lchr[lp->lnd_type].l_flags & L_TRAIN) &&
-	    lp->lnd_item[I_MILIT] == 0) {
-	    lnd_stays(actor, "has no mil on it to guide it", llp);
-	    continue;
-	}
-	if (relations_with(sect.sct_own, actor) != ALLIED &&
-	    !(lchr[lp->lnd_type].l_flags & L_SPY) &&
-	    sect.sct_own) {
-	    sprintf(mess, "has been kidnapped by %s", cname(sect.sct_own));
-	    lnd_stays(actor, mess, llp);
+
+	snprintf(and_stays, sizeof(and_stays), " & stays in %s",
+		 xyas(lp->lnd_x, lp->lnd_y, actor));
+	if (!lnd_may_mar(lp, ldr, and_stays)) {
+	    lnd_mar_put_one(llp);
 	    continue;
 	}
-	if (first) {
-	    allx = lp->lnd_x;
-	    ally = lp->lnd_y;
-	    first = 0;
-	}
-	if (lp->lnd_x != allx || lp->lnd_y != ally)
-	    *togetherp = 0;
+
+	if (!ldr)
+	    ldr = lp;
 	if (lp->lnd_mobil + 1 < (int)llp->mobil) {
 	    llp->mobil = lp->lnd_mobil;
 	}
-	if (llp->mobil < *minmobp)
-	    *minmobp = llp->mobil;
-	if (llp->mobil > *maxmobp)
-	    *maxmobp = llp->mobil;
     }
 }
 
+static void
+lnd_mar_put_one(struct ulist *llp)
+{
+    if (llp->mobil < -127)
+	llp->mobil = -127;
+    llp->unit.land.lnd_mobil = llp->mobil;
+    lnd_put_one(llp);
+}
+
+void
+lnd_mar_put(struct emp_qelem *list, natid actor)
+{
+    struct emp_qelem *qp, *next;
+    struct ulist *llp;
+    struct lndstr *lp;
+
+    for (qp = list->q_back; qp != list; qp = next) {
+	next = qp->q_back;
+	llp = (struct ulist *)qp;
+	lp = &llp->unit.land;
+	mpr(actor, "%s stopped at %s\n",
+	    prland(lp), xyas(lp->lnd_x, lp->lnd_y, actor));
+	lnd_mar_put_one(llp);
+    }
+}
+
+void
+lnd_put(struct emp_qelem *list)
+{
+    struct emp_qelem *qp, *next;
+
+    for (qp = list->q_back; qp != list; qp = next) {
+	next = qp->q_back;
+	lnd_put_one((struct ulist *)qp);
+    }
+}
+
+void
+lnd_put_one(struct ulist *llp)
+{
+    putland(llp->unit.land.lnd_uid, &llp->unit.land);
+    emp_remque(&llp->queue);
+    free(llp);
+}
+
 /*
  * Sweep landmines with engineers in LAND_LIST for ACTOR.
+ * All land units in LAND_LIST must be in the same sector.
  * If EXPLICIT is non-zero, this is for an explicit sweep command from
  * a player.  Else it's an automatic "on the move" sweep.
  * If TAKEMOB is non-zero, require and charge mobility.
+ * Return non-zero when the land units should stop.
  */
-void
+int
 lnd_sweep(struct emp_qelem *land_list, int explicit, int takemob,
 	  natid actor)
 {
@@ -537,43 +626,57 @@ lnd_sweep(struct emp_qelem *land_list, int explicit, int takemob,
     struct ulist *llp;
     struct sctstr sect;
     int mines, m, max, sshells, lshells;
+    int stopping = 0, first = 1;
+
+    llp = lnd_find_capable(land_list, L_ENGINEER);
+    if (!llp) {
+	if (explicit)
+	    mpr(actor, "No engineers!\n");
+	return 0;
+    }
+
+    getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
+    if (!explicit
+	&& relations_with(sect.sct_oldown, actor) == ALLIED)
+	return 0;
+    if (SCT_MINES_ARE_SEAMINES(&sect)) {
+	if (explicit)
+	    mpr(actor, "%s is a %s.  No landmines there!\n",
+		xyas(sect.sct_x, sect.sct_y, actor),
+		dchr[sect.sct_type].d_name);
+	return 0;
+    }
 
     for (qp = land_list->q_back; qp != land_list; qp = next) {
 	next = qp->q_back;
 	llp = (struct ulist *)qp;
-	if (!(((struct lchrstr *)llp->chrp)->l_flags & L_ENGINEER)) {
-	    if (explicit)
-		mpr(actor, "%s is not an engineer!\n",
-		    prland(&llp->unit.land));
-	    continue;
-	}
-	if (takemob && llp->mobil < 0.0) {
-	    if (explicit)
-		lnd_stays(actor, "is out of mobility", llp);
-	    continue;
-	}
-	getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
-	if (!explicit && relations_with(sect.sct_oldown, actor) == ALLIED)
+	if (!(lchr[llp->unit.land.lnd_type].l_flags & L_ENGINEER))
 	    continue;
-	if (SCT_MINES_ARE_SEAMINES(&sect)) {
-	    if (explicit)
-		mpr(actor, "%s is in a %s sector.  No landmines there!\n",
-		    prland(&llp->unit.land), dchr[sect.sct_type].d_name);
-	    continue;
-	}
 	if (takemob) {
+	    if (llp->mobil <= 0.0) {
+		if (explicit)
+		    mpr(actor, "%s is out of mobility!\n",
+			prland(&llp->unit.land));
+		continue;
+	    }
 	    llp->mobil -= lnd_pathcost(&llp->unit.land, 0.2);
 	    llp->unit.land.lnd_mobil = (int)llp->mobil;
 	    llp->unit.land.lnd_harden = 0;
 	}
 	putland(llp->unit.land.lnd_uid, &llp->unit.land);
+	getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
 	if (!(mines = sect.sct_mines))
 	    continue;
-	max = ((struct lchrstr *)llp->chrp)->l_item[I_SHELL];
+	max = lchr[llp->unit.land.lnd_type].l_item[I_SHELL];
 	lshells = llp->unit.land.lnd_item[I_SHELL];
 	sshells = sect.sct_item[I_SHELL];
 	for (m = 0; mines > 0 && m < max * 2; m++) {
-	    if (chance(0.5 * ((struct lchrstr *)llp->chrp)->l_att)) {
+	    if (chance(0.5 * lchr[llp->unit.land.lnd_type].l_att)) {
+		if (first) {
+		    mpr(actor, "Approaching minefield at %s...\n",
+			xyas(sect.sct_x, sect.sct_y, actor));
+		    first = 0;
+		}
 		mpr(actor, "Sweep...\n");
 		mines--;
 		if (lshells < max)
@@ -587,21 +690,31 @@ lnd_sweep(struct emp_qelem *land_list, int explicit, int takemob,
 	sect.sct_item[I_SHELL] = sshells;
 	putland(llp->unit.land.lnd_uid, &llp->unit.land);
 	putsect(&sect);
+	stopping |= lnd_check_one_mines(llp, 1);
     }
+    return stopping;
 }
 
 static int
-contains_engineer(struct emp_qelem *list)
+lnd_check_one_mines(struct ulist *llp, int with_eng)
 {
-    struct emp_qelem *qp;
-    struct emp_qelem *next;
-    struct ulist *llp;
+    struct sctstr sect;
 
-    for (qp = list->q_back; qp != list; qp = next) {
-	next = qp->q_back;
-	llp = (struct ulist *)qp;
-	if (((struct lchrstr *)llp->chrp)->l_flags & L_ENGINEER)
-	    return 1;
+    getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
+    if (SCT_LANDMINES(&sect) == 0)
+	return 0;
+    if (relations_with(sect.sct_oldown, llp->unit.land.lnd_own) == ALLIED)
+	return 0;
+    if (chance(DMINE_LHITCHANCE(sect.sct_mines) / (1 + 2 * with_eng))) {
+	lnd_hit_mine(&llp->unit.land);
+	sect.sct_mines--;
+	putsect(&sect);
+	putland(llp->unit.land.lnd_uid, &llp->unit.land);
+	if (!llp->unit.land.lnd_own) {
+	    emp_remque(&llp->queue);
+	    free(llp);
+	}
+	return 1;
     }
     return 0;
 }
@@ -611,59 +724,25 @@ lnd_check_mines(struct emp_qelem *land_list)
 {
     struct emp_qelem *qp;
     struct emp_qelem *next;
-    struct ulist *llp;
-    struct sctstr sect;
     int stopping = 0;
-    int with_eng = contains_engineer(land_list);
+    int with_eng = !!lnd_find_capable(land_list, L_ENGINEER);
 
     for (qp = land_list->q_back; qp != land_list; qp = next) {
 	next = qp->q_back;
-	llp = (struct ulist *)qp;
-	getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
-	if (SCT_LANDMINES(&sect) == 0)
-	    continue;
-	if (relations_with(sect.sct_oldown, llp->unit.land.lnd_own)
-	    == ALLIED)
-	    continue;
-	if (chance(DMINE_LHITCHANCE(sect.sct_mines) / (1 + 2 * with_eng))) {
-	    lnd_hit_mine(&llp->unit.land);
-	    sect.sct_mines--;
-	    putsect(&sect);
-	    putland(llp->unit.land.lnd_uid, &llp->unit.land);
-	    if (!llp->unit.land.lnd_own) {
-		stopping = 1;
-		emp_remque(qp);
-		free(qp);
-	    }
-	}
+	stopping |= lnd_check_one_mines((struct ulist *)qp, with_eng);
     }
     return stopping;
 }
 
-static void
-lnd_stays(natid actor, char *str, struct ulist *llp)
+/* Return whether and why SP would be stuck in SECTP.  */
+enum lnd_stuck
+lnd_check_mar(struct lndstr *lp, struct sctstr *sectp)
 {
-    mpr(actor, "%s %s & stays in %s\n",
-	prland(&llp->unit.land), str,
-	xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y, actor));
-    if (llp->mobil < -127)
-	llp->mobil = -127;
-    llp->unit.land.lnd_mobil = llp->mobil;
-    lnd_delete(llp);
-}
-
-static int
-lnd_count(struct emp_qelem *list)
-{
-    struct emp_qelem *qp;
-    struct emp_qelem *next;
-    int count = 0;
-
-    for (qp = list->q_back; qp != list; qp = next) {
-	next = qp->q_back;
-	++count;
-    }
-    return count;
+    if (dchr[sectp->sct_type].d_mob0 < 0)
+	return LND_STUCK_IMPASSABLE;
+    if (lnd_mobtype(lp) == MOB_RAIL && !SCT_HAS_RAIL(sectp))
+	return LND_STUCK_NO_RAIL;
+    return LND_STUCK_NOT;
 }
 
 static int
@@ -675,7 +754,7 @@ lnd_damage(struct emp_qelem *list, int totdam)
     int dam;
     int count;
 
-    if (!totdam || !(count = lnd_count(list)))
+    if (!totdam || !(count = emp_quelen(list)))
 	return 0;
     dam = ldround((double)totdam / count, 1);
     for (qp = list->q_back; qp != list; qp = next) {
@@ -718,7 +797,7 @@ static int
 lnd_missile_interdiction(struct emp_qelem *list, coord newx, coord newy,
 			 natid victim)
 {
-    int mindam = lnd_count(list) * 20;
+    int mindam = emp_quelen(list) * 20;
     int hardtarget = lnd_easiest_target(list);
     int dam, newdam, sublaunch;
     int stopping = 0;
@@ -896,92 +975,114 @@ lnd_mobcost(struct lndstr *lp, struct sctstr *sp)
     return lnd_pathcost(lp, sector_mcost(sp, lnd_mobtype(lp)));
 }
 
+/*
+ * Ask user to confirm sector abandonment, if any.
+ * All land units in LIST must be in the same sector.
+ * If removing the land units in LIST would abandon their sector, ask
+ * the user to confirm.
+ * Return zero when abandonment was declined, else non-zero.
+ */
+int lnd_abandon_askyn(struct emp_qelem *list)
+{
+    struct ulist *llp;
+    struct sctstr sect;
+    struct emp_qelem *qp;
+
+    if (QEMPTY(list))
+	return 1;
+    llp = (struct ulist *)list->q_back;
+    getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
+    if (!abandon_askyn(&sect, I_CIVIL, 0, llp))
+	return 0;
+    if (!check_sect_ok(&sect))
+	return 0;
+    for (qp = list->q_back; qp != list; qp = qp->q_back) {
+	if (!check_land_ok(&((struct ulist *)qp)->unit.land))
+	    return 0;
+    }
+    return 1;
+}
+
 int
-lnd_mar_one_sector(struct emp_qelem *list, int dir, natid actor,
-		   int together)
+lnd_mar_dir(struct emp_qelem *list, int dir, natid actor)
 {
     struct sctstr sect, osect;
     struct emp_qelem *qp;
-    struct emp_qelem *qp2;
     struct emp_qelem *next;
     struct ulist *llp;
-    struct emp_qelem cur, done;
     coord dx;
     coord dy;
     coord newx;
     coord newy;
-    int stopping = 0;
-    int visible;
-    int stop;
-    char dp[80];
+    int move;
     int rel;
     int oldown;
 
-    if (dir <= DIR_STOP || dir >= DIR_VIEW) {
-	unit_put(list, actor);
+    if (CANT_HAPPEN(QEMPTY(list)))
+	return 1;
+
+    if (dir <= DIR_STOP || dir > DIR_LAST) {
+	CANT_HAPPEN(dir != DIR_STOP);
+	lnd_mar_put(list, actor);
 	return 1;
     }
     dx = diroff[dir][0];
     dy = diroff[dir][1];
+
+    llp = (struct ulist *)list->q_back;
+    getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &osect);
+    oldown = osect.sct_own;
+    newx = xnorm(llp->unit.land.lnd_x + dx);
+    newy = ynorm(llp->unit.land.lnd_y + dy);
+    getsect(newx, newy, &sect);
+    rel = sect.sct_own ? relations_with(sect.sct_own, actor) : ALLIED;
+
+    move = 0;
     for (qp = list->q_back; qp != list; qp = next) {
 	next = qp->q_back;
 	llp = (struct ulist *)qp;
-	getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &osect);
-	oldown = osect.sct_own;
-	newx = xnorm(llp->unit.land.lnd_x + dx);
-	newy = ynorm(llp->unit.land.lnd_y + dy);
-	getsect(newx, newy, &sect);
-	rel = relations_with(sect.sct_own, actor);
-	if ((rel != ALLIED &&
-	     !(lchr[(int)llp->unit.land.lnd_type].l_flags & L_SPY) &&
-	     sect.sct_own) || (sect.sct_type == SCT_WATER ||
-			       sect.sct_type == SCT_SANCT ||
-			       sect.sct_type == SCT_WASTE)) {
-	    if (together) {
-		mpr(actor, "can't go to %s\n", xyas(newx, newy, actor));
-		return 1;
-	    } else {
-		sprintf(dp, "can't go to %s", xyas(newx, newy, actor));
-		lnd_stays(actor, dp, llp);
-		continue;
-	    }
-	}
-	if (!SCT_HAS_RAIL(&sect)
-	    && lnd_mobtype(&llp->unit.land) == MOB_RAIL) {
-	    if (together) {
+	switch (lnd_check_mar(&llp->unit.land, &sect)) {
+	case LND_STUCK_NOT:
+	    if (rel == ALLIED
+		|| (lchr[llp->unit.land.lnd_type].l_flags & L_SPY))
+		move = 1;
+	    break;
+	case LND_STUCK_NO_RAIL:
+	    if (rel == ALLIED)
 		mpr(actor, "no rail system in %s\n",
 		    xyas(newx, newy, actor));
-		return 1;
-	    } else {
-		sprintf(dp, "has no rail system in %s",
-			xyas(newx, newy, actor));
-		lnd_stays(actor, dp, llp);
-		continue;
-	    }
+	    else
+		mpr(actor, "can't go to %s\n", xyas(newx, newy, actor));
+	    return 1;
+	default:
+	    CANT_REACH();
+	    /* fall through */
+	case LND_STUCK_IMPASSABLE:
+	    mpr(actor, "can't go to %s\n", xyas(newx, newy, actor));
+	    return 1;
 	}
-	/* Note we check would_abandon first because we don't want
-	   to always have to do these checks */
-	if (would_abandon(&osect, I_CIVIL, 0, &llp->unit.land)) {
-	    stop = 0;
-	    if (!want_to_abandon(&osect, I_CIVIL, 0, &llp->unit.land)) {
-		stop = 1;
-	    }
-	    /* now check stuff */
-	    if (!check_sect_ok(&sect))
-		return 1;
-	    if (!check_sect_ok(&osect))
-		return 1;
-	    for (qp2 = list->q_back; qp2 != list; qp2 = qp2->q_back) {
-		if (!check_land_ok(&((struct ulist *)qp2)->unit.land))
-		    return 1;
-	    }
-	    if (stop) {
-		lnd_stays(actor, "stops", llp);
-		continue;
-	    }
+    }
+    if (!move) {
+	mpr(actor, "can't go to %s\n", xyas(newx, newy, actor));
+	return 1;
+    }
+
+    for (qp = list->q_back; qp != list; qp = next) {
+	next = qp->q_back;
+	llp = (struct ulist *)qp;
+	if (rel != ALLIED
+	    && !(lchr[llp->unit.land.lnd_type].l_flags & L_SPY)) {
+	    mpr(actor, "%s can't go to %s & stays in %s\n",
+		prland(&llp->unit.land), xyas(newx, newy, actor),
+		xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y, actor));
+	    lnd_mar_put_one(llp);
+	    continue;
 	}
 	if (llp->mobil <= 0.0) {
-	    lnd_stays(actor, "is out of mobility", llp);
+	    mpr(actor, "%s is out of mobility & stays in %s\n",
+		prland(&llp->unit.land),
+		xyas(llp->unit.land.lnd_x, llp->unit.land.lnd_y, actor));
+	    lnd_mar_put_one(llp);
 	    continue;
 	}
 	llp->unit.land.lnd_x = newx;
@@ -997,7 +1098,8 @@ lnd_mar_one_sector(struct emp_qelem *list, int dir, natid actor,
 	    mpr(actor, "You no longer own %s\n",
 		xyas(osect.sct_x, osect.sct_y, actor));
 	}
-	if (rel != ALLIED && sect.sct_own) {	/* must be a spy */
+	if (rel != ALLIED) {
+	    /* must be a spy */
 	    /* Always a 10% chance of getting caught. */
 	    if (chance(LND_SPY_DETECT_CHANCE(llp->unit.land.lnd_effic))) {
 		if (rel == NEUTRAL || rel == FRIENDLY) {
@@ -1013,50 +1115,41 @@ lnd_mar_one_sector(struct emp_qelem *list, int dir, natid actor,
 			prland(&llp->unit.land));
 		    llp->unit.land.lnd_effic = 0;
 		    putland(llp->unit.land.lnd_uid, &llp->unit.land);
-		    lnd_delete(llp);
+		    lnd_put_one(llp);
 		}
 	    }
 	}
     }
+
+    return 0;
+}
+
+int
+lnd_mar_gauntlet(struct emp_qelem *list, int interdict, natid actor)
+{
+    struct ulist *mlp = (struct ulist *)list->q_back;
+    coord newx = mlp->unit.land.lnd_x;
+    coord newy = mlp->unit.land.lnd_y;
+    int stopping, visible;
+    struct emp_qelem *qp, *next;
+    struct ulist *llp;
+
+    stopping = lnd_sweep(list, 0, 1, actor);
     if (QEMPTY(list))
 	return stopping;
-    lnd_sweep(list, 0, 1, actor);
     stopping |= lnd_check_mines(list);
     if (QEMPTY(list))
 	return stopping;
 
-    /* interdict land units sector by sector */
-    emp_initque(&cur);
-    emp_initque(&done);
-    while (!QEMPTY(list)) {
-	llp = (struct ulist *)list->q_back;
-	newx = llp->unit.land.lnd_x;
-	newy = llp->unit.land.lnd_y;
-	/* move units in NEWX,NEWY to cur */
-	visible = 0;
-	for (qp = list->q_back; qp != list; qp = next) {
-	    next = qp->q_back;
-	    llp = (struct ulist *)qp;
-	    if (llp->unit.land.lnd_x == newx && llp->unit.land.lnd_y == newy) {
-		emp_remque(qp);
-		emp_insque(qp, &cur);
-		if (!(lchr[(int)llp->unit.land.lnd_type].l_flags & L_SPY))
-		    visible = 1;
-	    }
-	}
-	/* interdict them */
-	if (visible)
-	    stopping |= lnd_interdict(&cur, newx, newy, actor);
-	/* move survivors to done */
-	for (qp = cur.q_back; qp != &cur; qp = next) {
-	    next = qp->q_back;
-	    emp_remque(qp);
-	    emp_insque(qp, &done);
-	}
+    visible = 0;
+    for (qp = list->q_back; qp != list; qp = next) {
+	next = qp->q_back;
+	llp = (struct ulist *)qp;
+	if (!(lchr[(int)llp->unit.land.lnd_type].l_flags & L_SPY))
+	    visible = 1;
     }
-    /* assign surviving land units back to list */
-    emp_insque(list, &done);
-    emp_remque(&done);
+    if (visible && interdict)
+	stopping |= lnd_interdict(list, newx, newy, actor);
 
     return stopping;
 }