(trad, set): Treat trade file slots with zero owner as unused, so that

freshly extended trade file makes sense.  When set() removes a lot,
simply zero the slot.

(set): Initialize trd_uid.

(trade_check_ok): Use check_land_ok() & friends instead of doing it by
hand, but wrong.  This fixes bying planes and land units loaded on
ships that moved after loading.

(check_trade_ok): New.
(trade_check_ok): Use it.  Remove unused argument lot.  Callers
changed.

include/prototypes.h

@@ -111,6 +111,7 @@ extern int check_nuke_ok(struct nukstr *);
 extern int check_plane_ok(struct plnstr *);
 extern int check_comm_ok(struct comstr *);
 extern int check_loan_ok(struct lonstr *);
+extern int check_trade_ok(struct trdstr *);
 /* fsize.c */
 extern int fsize(int);
 extern int blksize(int);

include/trade.h

@@ -73,7 +73,7 @@ union trdgenstr {
     struct shpstr shp;
 };
 
-extern int trade_check_ok(int, struct trdstr *, union trdgenstr *);
+extern int trade_check_ok(struct trdstr *, union trdgenstr *);
 extern s_char *trade_nameof(struct trdstr *, union trdgenstr *);
 extern int trade_desc(struct trdstr *, union trdgenstr *);
 extern int trade_getitem(struct trdstr *, union trdgenstr *);

src/lib/commands/set.c

@@ -116,34 +116,21 @@ set(void)
 	freeslot = -1;
 	snxtitem_all(&ni_trade, EF_TRADE);
 	while (nxtitem(&ni_trade, (char *)&trade)) {
-	    if (trade.trd_unitid < 0)
+	    if (trade.trd_owner == 0)
 		freeslot = ni_trade.cur;
 	    if (trade.trd_unitid == ni.cur && trade.trd_type == type) {
 		foundslot = ni_trade.cur;
 		break;
 	    }
 	}
-	if (price == 0 && foundslot >= 0) {
+	if (price <= 0) {
-	    pr("%s #%d (lot #%d) removed from trading\n",
+	    if (foundslot >= 0) {
-	       trade_nameof(&trade, &item), ni.cur, foundslot);
+		pr("%s #%d (lot #%d) removed from trading\n",
-	    trade.trd_type = 0;
+		   trade_nameof(&trade, &item), ni.cur, foundslot);
-	    trade.trd_owner = 0;
+		memset(&trade, 0, sizeof(trade));
-	    trade.trd_unitid = -1;
+		puttrade(ni_trade.cur, &trade);
-	    trade.trd_price = 0;
+	    }
-	    (void)time(&now);
+	} else {
-	    trade.trd_markettime = now;
-	    trade.trd_maxbidder = player->cnum;
-	    puttrade(ni_trade.cur, &trade);
-	} else if (price > 0) {
-	    trade.trd_x = item.gen.trg_x;
-	    trade.trd_y = item.gen.trg_x;
-	    trade.trd_type = type;
-	    trade.trd_owner = player->cnum;
-	    trade.trd_unitid = ni.cur;
-	    trade.trd_price = price;
-	    (void)time(&now);
-	    trade.trd_markettime = now;
-	    trade.trd_maxbidder = player->cnum;
 	    if (foundslot >= 0)
 		id = foundslot;
 	    else if (freeslot >= 0)
@@ -152,6 +139,16 @@ set(void)
 		ef_extend(EF_TRADE, 1);
 		id = ni_trade.cur;
 	    }
+	    trade.trd_x = item.gen.trg_x;
+	    trade.trd_y = item.gen.trg_x;
+	    trade.trd_type = type;
+	    trade.trd_owner = player->cnum;
+	    trade.trd_uid = id;
+	    trade.trd_unitid = ni.cur;
+	    trade.trd_price = price;
+	    (void)time(&now);
+	    trade.trd_markettime = now;
+	    trade.trd_maxbidder = player->cnum;
 	    puttrade(id, &trade);
 	    pr("%s #%d (lot #%d) price %s to $%d\n",
 	       trade_nameof(&trade, &item), ni.cur,

src/lib/commands/trad.c

@@ -98,7 +98,7 @@ trad(void)
 
     snxtitem_all(&ni, EF_TRADE);
     while (nxtitem(&ni, (char *)&trade)) {
-	if (trade.trd_unitid < 0)
+	if (trade.trd_owner == 0)
 	    continue;
 	if (!trade_getitem(&trade, &tg)) {
 	    continue;
@@ -205,7 +205,7 @@ trad(void)
 	plflags = plchr[(int)tg.pln.pln_type].pl_flags;
 	while (1) {
 	    p = getstring("Destination sector: ", buf);
-	    if (!trade_check_ok(lotno, &trade, &tg))
+	    if (!trade_check_ok(&trade, &tg))
 		return RET_FAIL;
 	    if (p == 0) {
 		return RET_FAIL;
@@ -234,7 +234,7 @@ trad(void)
     if (trade.trd_type == EF_LAND) {
 	while (1) {
 	    p = getstring("Destination sector: ", buf);
-	    if (!trade_check_ok(lotno, &trade, &tg))
+	    if (!trade_check_ok(&trade, &tg))
 		return RET_FAIL;
 	    if (p == 0) {
 		return RET_FAIL;
@@ -266,7 +266,7 @@ trad(void)
 
     if ((p = getstring("How much do you bid: ", buf)) == 0 || *p == 0)
 	return RET_OK;
-    if (!trade_check_ok(lotno, &trade, &tg))
+    if (!trade_check_ok(&trade, &tg))
 	return RET_FAIL;
     bid = atoi(p);
     if (bid < price)

src/lib/common/check.c

@@ -161,3 +161,16 @@ check_comm_ok(struct comstr *commp)
     }
     return 1;
 }
+
+int
+check_trade_ok(struct trdstr *tp)
+{
+    struct trdstr chktrade;
+
+    gettrade(tp->trd_uid, &chktrade);
+    if (memcmp(tp, &chktrade, sizeof(struct trdstr))) {
+	pr("Trade lot #%d has changed!\n", tp->trd_uid);
+	return 0;
+    }
+    return 1;
+}

src/lib/subs/trdsub.c

@@ -52,31 +52,25 @@
 #include "optlist.h"
 
 int
-trade_check_ok(int lot, struct trdstr *tp, union trdgenstr *tgp)
+trade_check_ok(struct trdstr *tp, union trdgenstr *tgp)
 {
     union trdgenstr check;
-    struct trdstr trade;
+
-    int result = 0;
+    if (!check_trade_ok(tp))
+	return 0;
 
     trade_getitem(tp, &check);
     if (tp->trd_type == EF_LAND)
-	result = memcmp(&(check.lnd), &(tgp->lnd), sizeof(struct lndstr));
+	return check_land_ok(&tgp->lnd);
-    else if (tp->trd_type == EF_PLANE)
+    if (tp->trd_type == EF_PLANE)
-	result = memcmp(&(check.pln), &(tgp->pln), sizeof(struct plnstr));
+	return check_plane_ok(&tgp->pln);
-    else if (tp->trd_type == EF_SHIP)
+    if (tp->trd_type == EF_SHIP)
-	result = memcmp(&(check.shp), &(tgp->shp), sizeof(struct shpstr));
+	return check_ship_ok(&tgp->shp);
-    else
+    if (tp->trd_type == EF_NUKE)
-	result = memcmp(&(check.nuk), &(tgp->nuk), sizeof(struct nukstr));
+	return check_nuke_ok(&tgp->nuk);
-    if (result) {
+    CANT_HAPPEN("Bad TRD_TYPE");
-	pr("That item has changed!\n");
+    pr("Trade lot #%d went bad!\n", tp->trd_uid);
-	return 0;
+    return 0;
-    }
-    gettrade(lot, &trade);
-    if (memcmp((s_char *)&trade, (s_char *)tp, sizeof(struct trdstr))) {
-	pr("That item has changed!\n");
-	return 0;
-    }
-    return 1;
 }
 
 s_char *