From: Eric S. Raymond <esr@thyrsus.com>
Date: Fri, 22 Sep 2006 11:38:54 +0000 (+0000)
Subject: Abstract away the operations involving a sentinel value for coordinates.
X-Git-Tag: 2.0~203
X-Git-Url: https://jxself.org/git/?p=super-star-trek.git;a=commitdiff_plain;h=4207ce95e80fe7e2d5114079fa4255e0ad506618

Abstract away the operations involving a sentinel value for coordinates.

Besides making the code more readable, the sentinel may change someday
if we go zero-origin everywhere.
---

diff --git a/src/battle.c b/src/battle.c
index 9fc6082..f4c6e90 100644
--- a/src/battle.c
+++ b/src/battle.c
@@ -387,7 +387,7 @@ void torpedo(double course, double r, coord in, double *hit, int i, int n)
 	    q->planet = NOPLANET;
 	    DESTROY(&game.state.plnets[game.iplnet]);
 	    game.iplnet = 0;
-	    game.plnet.x = game.plnet.y = 0;
+	    invalidate(game.plnet);
 	    game.quad[w.x][w.y] = IHDOT;
 	    if (game.landed) {
 		/* captain perishes on planet */
@@ -401,7 +401,7 @@ void torpedo(double course, double r, coord in, double *hit, int i, int n)
 	    q->planet = NOPLANET;
 	    DESTROY(&game.state.plnets[game.iplnet]);
 	    game.iplnet = 0;
-	    game.plnet.x = game.plnet.y = 0;
+	    invalidate(game.plnet);
 	    game.quad[w.x][w.y] = IHDOT;
 	    if (game.landed) {
 		/* captain perishes on planet */
@@ -719,7 +719,7 @@ void deadkl(coord w, feature type, coord mv)
     else if (type == IHQUEST) {
 	/* Killed a Thingy */
 	iqhere = iqengry = false;
-	thing.x =thing.y = 0;
+	invalidate(thing);
     }
     else {
 	/* Some type of a Klingon */
diff --git a/src/events.c b/src/events.c
index b4d4658..7acb042 100644
--- a/src/events.c
+++ b/src/events.c
@@ -317,7 +317,7 @@ void events(void)
 		if (i > game.state.remcom || game.state.rembase == 0 ||
 		    !game.state.galaxy[game.battle.x][game.battle.y].starbase) {
 		    /* No action to take after all */
-		    game.battle.x = game.battle.y = 0;
+		    invalidate(game.battle);
 		    break;
 		}
 	    }
@@ -358,9 +358,8 @@ void events(void)
 		game.battle = hold;
 		game.isatb = 0;
 	    }
-	    else {
-		game.battle.x = game.battle.y = 0;
-	    }
+	    else
+		invalidate(game.battle);
 	    break;
 	case FSCMOVE: /* Supercommander moves */
 	    schedule(FSCMOVE, 0.2777);
@@ -676,7 +675,8 @@ void nova(coord nov)
 			crmena(true, IHP, sector, scratch);
 			prout(_(" destroyed."));
 			DESTROY(&game.state.plnets[game.iplnet]);
-			game.iplnet = game.plnet.x = game.plnet.y = 0;
+			game.iplnet = 0;
+			invalidate(game.plnet);
 			if (game.landed) {
 			    finish(FPNOVA);
 			    return;
@@ -690,7 +690,7 @@ void nova(coord nov)
 				break;
 			game.state.baseq[i] = game.state.baseq[game.state.rembase];
 			game.state.rembase--;
-			game.base.x = game.base.y = 0;
+			invalidate(game.base);
 			game.state.basekl++;
 			newcnd();
 			crmena(true, IHB, sector, scratch);
@@ -875,7 +875,7 @@ void snova(bool induced, coord *w)
 	for (l = 1; l <= maxloop; l++) {
 	    if (same(game.state.kcmdr[l], nq)) {
 		game.state.kcmdr[l] = game.state.kcmdr[game.state.remcom];
-		game.state.kcmdr[game.state.remcom].x = game.state.kcmdr[game.state.remcom].y = 0;
+		invalidate(game.state.kcmdr[game.state.remcom]);
 		game.state.remcom--;
 		kldead--;
 		if (game.state.remcom==0) unschedule(FTBEAM);
@@ -902,7 +902,7 @@ void snova(bool induced, coord *w)
 	for (loop = 1; loop <= maxloop; loop++)
 	    if (same(game.state.baseq[loop], nq)) {
 		game.state.baseq[loop] = game.state.baseq[game.state.rembase];
-		game.state.baseq[game.state.rembase].x = game.state.baseq[game.state.rembase].y = 0;
+		invalidate(game.state.baseq[game.state.rembase]);
 		game.state.rembase--;
 		break;
 	    }
diff --git a/src/moving.c b/src/moving.c
index 948cdb4..3373b37 100644
--- a/src/moving.c
+++ b/src/moving.c
@@ -219,7 +219,7 @@ void dock(bool verbose)
 	prout(_("You must first leave standard orbit."));
 	return;
     }
-    if (game.base.x==0 || abs(game.sector.x-game.base.x) > 1 || abs(game.sector.y-game.base.y) > 1) {
+    if (!is_valid(game.base) || abs(game.sector.x-game.base.x) > 1 || abs(game.sector.y-game.base.y) > 1) {
 	crmshp();
 	prout(_(" not adjacent to base."));
 	return;
@@ -793,7 +793,7 @@ void timwrp()
 	game.isatb = 0;
 	unschedule(FCDBAS);
 	unschedule(FSCDBAS);
-	game.battle.x = game.battle.y = 0;
+	invalidate(game.battle);
 
 	/* Make sure Galileo is consistant -- Snapshot may have been taken
 	   when on planet, which would give us two Galileos! */
@@ -987,7 +987,7 @@ void mayday(void)
 	    break;
 	}
     }
-    if (game.sector.x==0){
+    if (!is_valid(game.sector)){
 	prout(_("You have been lost in space..."));
 	finish(FMATERIALIZE);
 	return;
diff --git a/src/planets.c b/src/planets.c
index a34b1f6..ca8996f 100644
--- a/src/planets.c
+++ b/src/planets.c
@@ -55,7 +55,7 @@ void orbit(void)
 	prout(_("Both warp and impulse engines damaged."));
 	return;
     }
-    if (game.plnet.x == 0 || abs(game.sector.x-game.plnet.x) > 1 || abs(game.sector.y-game.plnet.y) > 1) {
+    if (!is_valid(game.plnet) || abs(game.sector.x-game.plnet.x) > 1 || abs(game.sector.y-game.plnet.y) > 1) {
 	crmshp();
 	prout(_(" not adjacent to planet."));
 	skip(1);
diff --git a/src/setup.c b/src/setup.c
index 741f35f..44e378b 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -212,7 +212,7 @@ void setup(bool needprompt)
     for (i=0; i < NDEVICES; i++) 
 	game.damage[i] = 0.0;
     // Set up assorted game parameters
-    game.battle.x = game.battle.y = 0;
+    invalidate(game.battle);
     game.state.date = game.indate = 100.0*(int)(31.0*Rand()+20.0);
     game.nkinks = game.nhelp = game.casual = game.abandoned = 0;
     game.iscate = game.resting = game.imine = game.icrystl = game.icraft = false;
@@ -366,7 +366,7 @@ void setup(bool needprompt)
 	thing = randplace(GALSIZE);
     }
     else
-	thing.x = thing.y = 0;
+	invalidate(thing);
 
     skip(2);
     game.state.snap = false;
@@ -562,10 +562,10 @@ void newqad(bool shutup)
     struct quadrant *q;
 
     game.justin = true;
-    game.base.x = game.base.y = 0;
+    invalidate(game.base);
     game.klhere = 0;
     game.comhere = false;
-    game.plnet.x = game.plnet.y = 0;
+    invalidate(game.plnet);
     game.ishere = false;
     game.irhere = 0;
     game.iplnet = 0;
diff --git a/src/sst.h b/src/sst.h
index a397ed2..a9bf781 100644
--- a/src/sst.h
+++ b/src/sst.h
@@ -45,6 +45,8 @@ typedef struct {int x; int y;} coord;
 #define square(i)		((i)*(i))
 #define same(c1, c2)		((c1.x == c2.x) && (c1.y == c2.y))
 #define distance(c1, c2)	sqrt(square(c1.x - c2.x) + square(c1.y - c2.y))
+#define invalidate(w)		w.x = w.y = 0
+#define is_valid(w)		(w.x == 0 || w.y == 0)
 
 typedef struct {
     coord w;