more context (trunk only)

- reading spellbooks
- taking off

include/context.h

@@ -9,6 +9,8 @@
 #ifndef CONTEXT_H
 #define CONTEXT_H
 
+#define CONTEXTVERBSZ 30
+
 /*
  * The context structure houses things that the game tracks
  * or adjusts during the game, to preserve game state or context.
@@ -31,6 +33,20 @@ struct tin_info {
 	int	usedtime, reqtime;
 };
 
+struct book_info {
+	struct obj *book;	/* last/current book being xscribed */
+	unsigned o_id;		/* o_id of book in save file */
+	schar delay;		/* moves left for this spell */
+};
+
+struct takeoff_info {
+	long mask;
+	long what;
+	int delay;
+	boolean cancelled_don;
+	char disrobing[CONTEXTVERBSZ+1];
+};
+
 struct victual_info {
 	struct	obj *piece;	/* the thing being eaten, or last thing that
 				 * was partially eaten, unless that thing was
@@ -73,6 +89,8 @@ struct context_info {
 	struct dig_info digging;
 	struct victual_info victual;
 	struct tin_info tin;
+	struct book_info spbook;
+	struct takeoff_info takeoff;
 };
 
 extern NEARDATA struct context_info context;

include/patchlevel.h

@@ -13,7 +13,7 @@
  * Incrementing EDITLEVEL can be used to force invalidation of old bones
  * and save files.
  */
-#define EDITLEVEL	4
+#define EDITLEVEL	5
 
 #define COPYRIGHT_BANNER_A \
 "NetHack, Copyright 1985-2003"

src/do_wear.c

@@ -4,12 +4,6 @@
 
 #include "hack.h"
 
-STATIC_OVL NEARDATA long takeoff_mask = 0L;
-static NEARDATA long taking_off = 0L;
-
-static NEARDATA int todelay;
-static boolean cancelled_don = FALSE;
-
 static NEARDATA const char see_yourself[] = "see yourself";
 static NEARDATA const char unknown_type[] = "Unknown type of %s (%d)";
 static NEARDATA const char c_armor[]  = "armor",
@@ -141,7 +135,7 @@ Boots_off()
     setworn((struct obj *)0, W_ARMF);
     switch (otyp) {
 	case SPEED_BOOTS:
-		if (!Very_fast && !cancelled_don) {
+		if (!Very_fast && !context.takeoff.cancelled_don) {
 			makeknown(otyp);
 			You_feel("yourself slow down%s.",
 				Fast ? " a bit" : "");
@@ -149,14 +143,14 @@ Boots_off()
 		break;
 	case WATER_WALKING_BOOTS:
 		if (is_pool(u.ux,u.uy) && !Levitation && !Flying &&
-		    !is_clinger(youmonst.data) && !cancelled_don) {
+		    !is_clinger(youmonst.data) && !context.takeoff.cancelled_don) {
 			makeknown(otyp);
 			/* make boots known in case you survive the drowning */
 			spoteffects(TRUE);
 		}
 		break;
 	case ELVEN_BOOTS:
-		if (!oldprop && !HStealth && !BStealth && !cancelled_don) {
+		if (!oldprop && !HStealth && !BStealth && !context.takeoff.cancelled_don) {
 			makeknown(otyp);
 			You("sure are noisy.");
 		}
@@ -166,7 +160,7 @@ Boots_off()
 			HFumbling = EFumbling = 0;
 		break;
 	case LEVITATION_BOOTS:
-		if (!oldprop && !HLevitation && !cancelled_don) {
+		if (!oldprop && !HLevitation && !context.takeoff.cancelled_don) {
 			(void) float_down(0L, 0L);
 			makeknown(otyp);
 		}
@@ -179,7 +173,7 @@ Boots_off()
 		break;
 	default: impossible(unknown_type, c_boots, otyp);
     }
-    cancelled_don = FALSE;
+    context.takeoff.cancelled_don = FALSE;
     return 0;
 }
 
@@ -351,7 +345,7 @@ Helmet_off()
 	    context.botl = 1;
 	    break;
 	case CORNUTHAUM:
-	    if (!cancelled_don) {
+	    if (!context.takeoff.cancelled_don) {
 		ABON(A_CHA) += (Role_if(PM_WIZARD) ? -1 : 1);
 		context.botl = 1;
 	    }
@@ -362,7 +356,7 @@ Helmet_off()
 	    see_monsters();
 	    return 0;
 	case HELM_OF_BRILLIANCE:
-	    if (!cancelled_don) adj_abon(uarmh, -uarmh->spe);
+	    if (!context.takeoff.cancelled_don) adj_abon(uarmh, -uarmh->spe);
 	    break;
 	case HELM_OF_OPPOSITE_ALIGNMENT:
 	    u.ualign.type = u.ualignbase[A_CURRENT];
@@ -372,7 +366,7 @@ Helmet_off()
 	default: impossible(unknown_type, c_helmet, uarmh->otyp);
     }
     setworn((struct obj *)0, W_ARMH);
-    cancelled_don = FALSE;
+    context.takeoff.cancelled_don = FALSE;
     return 0;
 }
 
@@ -420,12 +414,12 @@ Gloves_off()
 	    context.botl = 1; /* taken care of in attrib.c */
 	    break;
 	case GAUNTLETS_OF_DEXTERITY:
-	    if (!cancelled_don) adj_abon(uarmg, -uarmg->spe);
+	    if (!context.takeoff.cancelled_don) adj_abon(uarmg, -uarmg->spe);
 	    break;
 	default: impossible(unknown_type, c_gloves, uarmg->otyp);
     }
     setworn((struct obj *)0, W_ARMG);
-    cancelled_don = FALSE;
+    context.takeoff.cancelled_don = FALSE;
     (void) encumber_msg();		/* immediate feedback for GoP */
 
     /* Prevent wielding cockatrice when not wearing gloves */
@@ -510,7 +504,7 @@ int
 Armor_off()
 {
     setworn((struct obj *)0, W_ARM);
-    cancelled_don = FALSE;
+    context.takeoff.cancelled_don = FALSE;
     return 0;
 }
 
@@ -521,7 +515,7 @@ int
 Armor_gone()
 {
     setnotworn(uarm);
-    cancelled_don = FALSE;
+    context.takeoff.cancelled_don = FALSE;
     return 0;
 }
 
@@ -947,7 +941,7 @@ cancel_don()
 	 * wasting time on it (and don't dereference it when donning would
 	 * otherwise finish)
 	 */
-	cancelled_don = (afternmv == Boots_on || afternmv == Helmet_on ||
+	context.takeoff.cancelled_don = (afternmv == Boots_on || afternmv == Helmet_on ||
 			 afternmv == Gloves_on || afternmv == Armor_on);
 	afternmv = 0;
 	nomovemsg = (char *)0;
@@ -1011,10 +1005,10 @@ dotakeoff()
 	    return 0;
 	}
 
-	reset_remarm();		/* clear takeoff_mask and taking_off */
+	reset_remarm();		/* clear context.takeoff.mask and context.takeoff.what */
 	(void) select_off(otmp);
-	if (!takeoff_mask) return 0;
-	reset_remarm();		/* armoroff() doesn't use takeoff_mask */
+	if (!context.takeoff.mask) return 0;
+	reset_remarm();		/* armoroff() doesn't use context.takeoff.mask */
 
 	(void) armoroff(otmp);
 	return(1);
@@ -1050,9 +1044,9 @@ doremring()
 		return(0);
 	}
 
-	reset_remarm();		/* clear takeoff_mask and taking_off */
+	reset_remarm();		/* clear context.takeoff.mask and context.takeoff.what */
 	(void) select_off(otmp);
-	if (!takeoff_mask) return 0;
+	if (!context.takeoff.mask) return 0;
 	reset_remarm();		/* not used by Ring_/Amulet_/Blindf_off() */
 
 	if (otmp == uright || otmp == uleft) {
@@ -1139,7 +1133,7 @@ register struct obj *otmp;
 		else setworn((struct obj *)0, otmp->owornmask & W_ARMOR);
 		off_msg(otmp);
 	}
-	takeoff_mask = taking_off = 0L;
+	context.takeoff.mask = context.takeoff.what = 0L;
 	return(1);
 }
 
@@ -1371,7 +1365,7 @@ dowear()
 /*		if(is_shield(otmp)) (void) Shield_on(); */
 		on_msg(otmp);
 	}
-	takeoff_mask = taking_off = 0L;
+	context.takeoff.mask = context.takeoff.what = 0L;
 	return(1);
 }
 
@@ -1754,22 +1748,22 @@ register struct obj *otmp;
 	    if (cursed(otmp)) return 0;
 	}
 
-	if(otmp == uarm) takeoff_mask |= WORN_ARMOR;
-	else if(otmp == uarmc) takeoff_mask |= WORN_CLOAK;
-	else if(otmp == uarmf) takeoff_mask |= WORN_BOOTS;
-	else if(otmp == uarmg) takeoff_mask |= WORN_GLOVES;
-	else if(otmp == uarmh) takeoff_mask |= WORN_HELMET;
-	else if(otmp == uarms) takeoff_mask |= WORN_SHIELD;
+	if(otmp == uarm) context.takeoff.mask |= WORN_ARMOR;
+	else if(otmp == uarmc) context.takeoff.mask |= WORN_CLOAK;
+	else if(otmp == uarmf) context.takeoff.mask |= WORN_BOOTS;
+	else if(otmp == uarmg) context.takeoff.mask |= WORN_GLOVES;
+	else if(otmp == uarmh) context.takeoff.mask |= WORN_HELMET;
+	else if(otmp == uarms) context.takeoff.mask |= WORN_SHIELD;
 #ifdef TOURIST
-	else if(otmp == uarmu) takeoff_mask |= WORN_SHIRT;
+	else if(otmp == uarmu) context.takeoff.mask |= WORN_SHIRT;
 #endif
-	else if(otmp == uleft) takeoff_mask |= LEFT_RING;
-	else if(otmp == uright) takeoff_mask |= RIGHT_RING;
-	else if(otmp == uamul) takeoff_mask |= WORN_AMUL;
-	else if(otmp == ublindf) takeoff_mask |= WORN_BLINDF;
-	else if(otmp == uwep) takeoff_mask |= W_WEP;
-	else if(otmp == uswapwep) takeoff_mask |= W_SWAPWEP;
-	else if(otmp == uquiver) takeoff_mask |= W_QUIVER;
+	else if(otmp == uleft) context.takeoff.mask |= LEFT_RING;
+	else if(otmp == uright) context.takeoff.mask |= RIGHT_RING;
+	else if(otmp == uamul) context.takeoff.mask |= WORN_AMUL;
+	else if(otmp == ublindf) context.takeoff.mask |= WORN_BLINDF;
+	else if(otmp == uwep) context.takeoff.mask |= W_WEP;
+	else if(otmp == uswapwep) context.takeoff.mask |= W_SWAPWEP;
+	else if(otmp == uquiver) context.takeoff.mask |= W_QUIVER;
 
 	else impossible("select_off: %s???", doname(otmp));
 
@@ -1781,61 +1775,59 @@ do_takeoff()
 {
 	register struct obj *otmp = (struct obj *)0;
 
-	if (taking_off == W_WEP) {
+	if (context.takeoff.what == W_WEP) {
 	  if(!cursed(uwep)) {
 	    setuwep((struct obj *) 0);
 	    You("are empty %s.", body_part(HANDED));
 	    u.twoweap = FALSE;
 	  }
-	} else if (taking_off == W_SWAPWEP) {
+	} else if (context.takeoff.what == W_SWAPWEP) {
 	  setuswapwep((struct obj *) 0);
 	  You("no longer have a second weapon readied.");
 	  u.twoweap = FALSE;
-	} else if (taking_off == W_QUIVER) {
+	} else if (context.takeoff.what == W_QUIVER) {
 	  setuqwep((struct obj *) 0);
 	  You("no longer have ammunition readied.");
-	} else if (taking_off == WORN_ARMOR) {
+	} else if (context.takeoff.what == WORN_ARMOR) {
 	  otmp = uarm;
 	  if(!cursed(otmp)) (void) Armor_off();
-	} else if (taking_off == WORN_CLOAK) {
+	} else if (context.takeoff.what == WORN_CLOAK) {
 	  otmp = uarmc;
 	  if(!cursed(otmp)) (void) Cloak_off();
-	} else if (taking_off == WORN_BOOTS) {
+	} else if (context.takeoff.what == WORN_BOOTS) {
 	  otmp = uarmf;
 	  if(!cursed(otmp)) (void) Boots_off();
-	} else if (taking_off == WORN_GLOVES) {
+	} else if (context.takeoff.what == WORN_GLOVES) {
 	  otmp = uarmg;
 	  if(!cursed(otmp)) (void) Gloves_off();
-	} else if (taking_off == WORN_HELMET) {
+	} else if (context.takeoff.what == WORN_HELMET) {
 	  otmp = uarmh;
 	  if(!cursed(otmp)) (void) Helmet_off();
-	} else if (taking_off == WORN_SHIELD) {
+	} else if (context.takeoff.what == WORN_SHIELD) {
 	  otmp = uarms;
 	  if(!cursed(otmp)) (void) Shield_off();
 #ifdef TOURIST
-	} else if (taking_off == WORN_SHIRT) {
+	} else if (context.takeoff.what == WORN_SHIRT) {
 	  otmp = uarmu;
 	  if(!cursed(otmp))
 	    setworn((struct obj *)0, uarmu->owornmask & W_ARMOR);
 #endif
-	} else if (taking_off == WORN_AMUL) {
+	} else if (context.takeoff.what == WORN_AMUL) {
 	  otmp = uamul;
 	  if(!cursed(otmp)) Amulet_off();
-	} else if (taking_off == LEFT_RING) {
+	} else if (context.takeoff.what == LEFT_RING) {
 	  otmp = uleft;
 	  if(!cursed(otmp)) Ring_off(uleft);
-	} else if (taking_off == RIGHT_RING) {
+	} else if (context.takeoff.what == RIGHT_RING) {
 	  otmp = uright;
 	  if(!cursed(otmp)) Ring_off(uright);
-	} else if (taking_off == WORN_BLINDF) {
+	} else if (context.takeoff.what == WORN_BLINDF) {
 	  if (!cursed(ublindf)) Blindf_off(ublindf);
-	} else impossible("do_takeoff: taking off %lx", taking_off);
+	} else impossible("do_takeoff: taking off %lx", context.takeoff.what);
 
 	return(otmp);
 }
 
-static const char *disrobing = "";
-
 STATIC_PTR
 int
 take_off()
@@ -1843,89 +1835,91 @@ take_off()
 	register int i;
 	register struct obj *otmp;
 
-	if (taking_off) {
-	    if (todelay > 0) {
-		todelay--;
+	if (context.takeoff.what) {
+	    if (context.takeoff.delay > 0) {
+		context.takeoff.delay--;
 		return(1);	/* still busy */
 	    } else {
 		if ((otmp = do_takeoff())) off_msg(otmp);
 	    }
-	    takeoff_mask &= ~taking_off;
-	    taking_off = 0L;
+	    context.takeoff.mask &= ~context.takeoff.what;
+	    context.takeoff.what = 0L;
 	}
 
 	for(i = 0; takeoff_order[i]; i++)
-	    if(takeoff_mask & takeoff_order[i]) {
-		taking_off = takeoff_order[i];
+	    if(context.takeoff.mask & takeoff_order[i]) {
+		context.takeoff.what = takeoff_order[i];
 		break;
 	    }
 
 	otmp = (struct obj *) 0;
-	todelay = 0;
+	context.takeoff.delay = 0;
 
-	if (taking_off == 0L) {
-	  You("finish %s.", disrobing);
+	if (context.takeoff.what == 0L) {
+	  You("finish %s.", context.takeoff.disrobing);
 	  return 0;
-	} else if (taking_off == W_WEP) {
-	  todelay = 1;
-	} else if (taking_off == W_SWAPWEP) {
-	  todelay = 1;
-	} else if (taking_off == W_QUIVER) {
-	  todelay = 1;
-	} else if (taking_off == WORN_ARMOR) {
+	} else if (context.takeoff.what == W_WEP) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == W_SWAPWEP) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == W_QUIVER) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == WORN_ARMOR) {
 	  otmp = uarm;
 	  /* If a cloak is being worn, add the time to take it off and put
 	   * it back on again.  Kludge alert! since that time is 0 for all
 	   * known cloaks, add 1 so that it actually matters...
 	   */
-	  if (uarmc) todelay += 2 * objects[uarmc->otyp].oc_delay + 1;
-	} else if (taking_off == WORN_CLOAK) {
+	  if (uarmc) context.takeoff.delay += 2 * objects[uarmc->otyp].oc_delay + 1;
+	} else if (context.takeoff.what == WORN_CLOAK) {
 	  otmp = uarmc;
-	} else if (taking_off == WORN_BOOTS) {
+	} else if (context.takeoff.what == WORN_BOOTS) {
 	  otmp = uarmf;
-	} else if (taking_off == WORN_GLOVES) {
+	} else if (context.takeoff.what == WORN_GLOVES) {
 	  otmp = uarmg;
-	} else if (taking_off == WORN_HELMET) {
+	} else if (context.takeoff.what == WORN_HELMET) {
 	  otmp = uarmh;
-	} else if (taking_off == WORN_SHIELD) {
+	} else if (context.takeoff.what == WORN_SHIELD) {
 	  otmp = uarms;
 #ifdef TOURIST
-	} else if (taking_off == WORN_SHIRT) {
+	} else if (context.takeoff.what == WORN_SHIRT) {
 	  otmp = uarmu;
 	  /* add the time to take off and put back on armor and/or cloak */
-	  if (uarm)  todelay += 2 * objects[uarm->otyp].oc_delay;
-	  if (uarmc) todelay += 2 * objects[uarmc->otyp].oc_delay + 1;
+	  if (uarm)  context.takeoff.delay += 2 * objects[uarm->otyp].oc_delay;
+	  if (uarmc) context.takeoff.delay += 2 * objects[uarmc->otyp].oc_delay + 1;
 #endif
-	} else if (taking_off == WORN_AMUL) {
-	  todelay = 1;
-	} else if (taking_off == LEFT_RING) {
-	  todelay = 1;
-	} else if (taking_off == RIGHT_RING) {
-	  todelay = 1;
-	} else if (taking_off == WORN_BLINDF) {
-	  todelay = 2;
+	} else if (context.takeoff.what == WORN_AMUL) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == LEFT_RING) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == RIGHT_RING) {
+	  context.takeoff.delay = 1;
+	} else if (context.takeoff.what == WORN_BLINDF) {
+	  context.takeoff.delay = 2;
 	} else {
-	  impossible("take_off: taking off %lx", taking_off);
+	  impossible("take_off: taking off %lx", context.takeoff.what);
 	  return 0;	/* force done */
 	}
 
-	if (otmp) todelay += objects[otmp->otyp].oc_delay;
+	if (otmp) context.takeoff.delay += objects[otmp->otyp].oc_delay;
 
 	/* Since setting the occupation now starts the counter next move, that
          * would always produce a delay 1 too big per item unless we subtract
 	 * 1 here to account for it.
 	 */
-	if (todelay>0) todelay--;
+	if (context.takeoff.delay>0) context.takeoff.delay--;
 
-	set_occupation(take_off, disrobing, 0);
+	set_occupation(take_off,
+		(context.takeoff.disrobing[0]) ?
+		context.takeoff.disrobing : (char *)0, 0);
 	return(1);		/* get busy */
 }
 
 void
 reset_remarm()
 {
-	taking_off = takeoff_mask = 0L;
-	disrobing = nul;
+	context.takeoff.what = context.takeoff.mask = 0L;
+	context.takeoff.disrobing[0] = '\0';
 }
 
 /* the 'A' command */
@@ -1934,9 +1928,9 @@ doddoremarm()
 {
     int result = 0;
 
-    if (taking_off || takeoff_mask) {
-	You("continue %s.", disrobing);
-	set_occupation(take_off, disrobing, 0);
+    if (context.takeoff.what || context.takeoff.mask) {
+	You("continue %s.", context.takeoff.disrobing);
+	set_occupation(take_off, context.takeoff.disrobing, 0);
 	(void) take_off();
 	return 0;
     } else if (!uwep && !uswapwep && !uquiver && !uamul && !ublindf &&
@@ -1950,13 +1944,13 @@ doddoremarm()
 	    (result = ggetobj("take off", select_off, 0, FALSE, (unsigned *)0)) < -1)
 	result = menu_remarm(result);
 
-    if (takeoff_mask) {
+    if (context.takeoff.mask) {
 	/* default activity for armor and/or accessories,
 	   possibly combined with weapons */
-	disrobing = "disrobing";
+	(void)strncpy(context.takeoff.disrobing, "disrobing", CONTEXTVERBSZ);
 	/* specific activity when handling weapons only */
-	if (!(takeoff_mask & ~(W_WEP|W_SWAPWEP|W_QUIVER)))
-	    disrobing = "disarming";
+	if (!(context.takeoff.mask & ~(W_WEP|W_SWAPWEP|W_QUIVER)))
+		(void)strncpy(context.takeoff.disrobing, "disarming", CONTEXTVERBSZ);
 	(void) take_off();
     }
     /* The time to perform the command is already completely accounted for

src/eat.c

@@ -351,6 +351,8 @@ do_reset_eat()
 	if (context.victual.piece) {
 		context.victual.o_id = 0;
 		context.victual.piece = touchfood(context.victual.piece);
+		if (context.victual.piece)
+			context.victual.o_id = context.victual.piece->o_id;
 		recalc_wt();
 	}
 	context.victual.fullwarn = context.victual.eating = context.victual.doreset = FALSE;
@@ -1147,7 +1149,8 @@ no_opener:
 	context.tin.reqtime = tmp;
 	context.tin.usedtime = 0;
 	context.tin.tin = otmp;
-	if (otmp) context.tin.o_id = otmp->o_id;
+	if (context.tin.tin)
+		context.tin.o_id = context.tin.tin->o_id;
 	set_occupation(opentin, "opening the tin", 0);
 	return;
 }
@@ -1955,6 +1958,7 @@ doeat()		/* generic "eat" command funtion (see cmd.c) */
 	 * they shouldn't be able to choke now.
 	 */
 	    if (u.uhs != SATIATED) context.victual.canchoke = FALSE;
+	    context.victual.o_id = 0;
 	    context.victual.piece = touchfood(otmp);
 	    if (context.victual.piece)
 	    	context.victual.o_id = context.victual.piece->o_id;
@@ -1974,6 +1978,7 @@ doeat()		/* generic "eat" command funtion (see cmd.c) */
 	/* KMH, conduct */
 	u.uconduct.food++;
 
+	context.victual.o_id = 0;
 	context.victual.piece = otmp = touchfood(otmp);
 	if (context.victual.piece)
 		context.victual.o_id = context.victual.piece->o_id;

src/restore.c

@@ -235,10 +235,12 @@ boolean ghostly, frozen;
 		if (otmp->bypass) otmp->bypass = 0;
 		if (!ghostly) {
 		    /* fix the pointers */
-		    if (context.victual.o_id == otmp->o_id)
+		    if (otmp->o_id == context.victual.o_id)
 			context.victual.piece = otmp;
-		    if (context.tin.o_id == otmp->o_id)
+		    if (otmp->o_id == context.tin.o_id)
 			context.tin.tin = otmp;
+		    if (otmp->o_id == context.spbook.o_id)
+			context.spbook.book = otmp;
 		}
 		otmp2 = otmp;
 	}

src/save.c

@@ -877,17 +877,34 @@ register struct obj *otmp;
 		saveobjchn(fd,otmp->cobj,mode);
 	    if (release_data(mode)) {
 /*		if (otmp->oclass == FOOD_CLASS) food_disappears(otmp); */
+		/*
+		 * If these are on the floor, the discarding could
+		 * be because of a game save, or we could just be changing levels.
+		 * Always invalidate the pointer, but ensure that we have
+		 * the o_id in order to restore the pointer on reload.
+		 */
 		if (otmp == context.victual.piece) {
 			/* Store the o_id of the victual if mismatched */
 			if (context.victual.o_id != otmp->o_id)
 			    context.victual.o_id = otmp->o_id;
+			/* invalidate the pointer; on reload it will get restored */
+			context.victual.piece = (struct obj *)0;
 		}
 		if (otmp == context.tin.tin) {
 			/* Store the o_id of your tin */
 			if (context.tin.o_id != otmp->o_id)
 			    context.tin.o_id = otmp->o_id;
+			/* invalidate the pointer; on reload it will get restored */
+			context.tin.tin = (struct obj *)0;
+		}
+/*		if (otmp->oclass == SPBOOK_CLASS) book_disappears(otmp); */
+		if (otmp == context.spbook.book) {
+			/* Store the o_id of your spellbook */
+			if (context.spbook.o_id != otmp->o_id)
+			    context.spbook.o_id = otmp->o_id;
+			/* invalidate the pointer; on reload it will get restored */
+			context.spbook.book = (struct obj *)0;
 		}
-		if (otmp->oclass == SPBOOK_CLASS) book_disappears(otmp);
 		otmp->where = OBJ_FREE;	/* set to free so dealloc will work */
 		otmp->timed = 0;	/* not timed any more */
 		otmp->lamplit = 0;	/* caller handled lights */

src/spell.c

@@ -4,9 +4,6 @@
 
 #include "hack.h"
 
-static NEARDATA schar delay;		/* moves left for this spell */
-static NEARDATA struct obj *book;	/* last/current book being xscribed */
-
 /* spellmenu arguments; 0 thru n-1 used as spl_book[] index when swapping */
 #define SPELLMENU_CAST (-2)
 #define SPELLMENU_VIEW (-1)
@@ -194,7 +191,7 @@ struct obj *spellbook;
 	    gone = TRUE;
 	} else {
 	    You("find yourself reading the %s line over and over again.",
-		spellbook == book ? "next" : "first");
+		spellbook == context.spbook.book ? "next" : "first");
 	}
 	return gone;
 }
@@ -321,22 +318,23 @@ learn()
 	boolean costly = TRUE;
 
 	/* JDS: lenses give 50% faster reading; 33% smaller read time */
-	if (delay && ublindf && ublindf->otyp == LENSES && rn2(2)) delay++;
+	if (context.spbook.delay && ublindf && ublindf->otyp == LENSES && rn2(2)) context.spbook.delay++;
 	if (Confusion) {		/* became confused while learning */
-	    (void) confused_book(book);
-	    book = 0;			/* no longer studying */
-	    nomul(delay);		/* remaining delay is uninterrupted */
-	    delay = 0;
+	    (void) confused_book(context.spbook.book);
+	    context.spbook.book = 0;			/* no longer studying */
+	    context.spbook.o_id = 0;
+	    nomul(context.spbook.delay);		/* remaining delay is uninterrupted */
+	    context.spbook.delay = 0;
 	    return(0);
 	}
-	if (delay) {	/* not if (delay++), so at end delay == 0 */
-	    delay++;
+	if (context.spbook.delay) {	/* not if (context.spbook.delay++), so at end delay == 0 */
+	    context.spbook.delay++;
 	    return(1); /* still busy */
 	}
 	exercise(A_WIS, TRUE);		/* you're studying. */
-	booktype = book->otyp;
+	booktype = context.spbook.book->otyp;
 	if(booktype == SPE_BOOK_OF_THE_DEAD) {
-	    deadbook(book);
+	    deadbook(context.spbook.book);
 	    return(0);
 	}
 
@@ -345,13 +343,13 @@ learn()
 		OBJ_NAME(objects[booktype]));
 	for (i = 0; i < MAXSPELL; i++)  {
 		if (spellid(i) == booktype)  {
-			if (book->spestudied > MAX_SPELL_STUDY) {
+			if (context.spbook.book->spestudied > MAX_SPELL_STUDY) {
 			    pline("This spellbook is too faint to be read any more.");
-			    book->otyp = booktype = SPE_BLANK_PAPER;
+			    context.spbook.book->otyp = booktype = SPE_BLANK_PAPER;
 			} else if (spellknow(i) <= 1000) {
 			    Your("knowledge of %s is keener.", splname);
 			    incrnknow(i);
-			    book->spestudied++;
+			    context.spbook.book->spestudied++;
 			    exercise(A_WIS,TRUE);       /* extra study */
 			} else { /* 1000 < spellknow(i) <= MAX_SPELL_STUDY */
 			    You("know %s quite well already.", splname);
@@ -365,7 +363,7 @@ learn()
 			spl_book[i].sp_id = booktype;
 			spl_book[i].sp_lev = objects[booktype].oc_level;
 			incrnknow(i);
-			book->spestudied++;
+			context.spbook.book->spestudied++;
 			You(i > 0 ? "add %s to your repertoire." : "learn %s.",
 			    splname);
 			makeknown((int)booktype);
@@ -374,15 +372,17 @@ learn()
 	}
 	if (i == MAXSPELL) impossible("Too many spells memorized!");
 
-	if (book->cursed) {	/* maybe a demon cursed it */
-	    if (cursed_book(book)) {
-		useup(book);
-		book = 0;
+	if (context.spbook.book->cursed) {	/* maybe a demon cursed it */
+	    if (cursed_book(context.spbook.book)) {
+		useup(context.spbook.book);
+		context.spbook.book = 0;
+		context.spbook.o_id = 0;
 		return 0;
 	    }
 	}
-	if (costly) check_unpaid(book);
-	book = 0;
+	if (costly) check_unpaid(context.spbook.book);
+	context.spbook.book = 0;
+	context.spbook.o_id = 0;
 	return(0);
 }
 
@@ -394,9 +394,9 @@ register struct obj *spellbook;
 	register boolean confused = (Confusion != 0);
 	boolean too_hard = FALSE;
 
-	if (delay && !confused && spellbook == book &&
+	if (context.spbook.delay && !confused && spellbook == context.spbook.book &&
 		    /* handle the sequence: start reading, get interrupted,
-		       have book become erased somehow, resume reading it */
+		       have context.spbook.book become erased somehow, resume reading it */
 		    booktype != SPE_BLANK_PAPER) {
 		You("continue your efforts to memorize the spell.");
 	} else {
@@ -409,20 +409,20 @@ register struct obj *spellbook;
 		switch (objects[booktype].oc_level) {
 		 case 1:
 		 case 2:
-			delay = -objects[booktype].oc_delay;
+			context.spbook.delay = -objects[booktype].oc_delay;
 			break;
 		 case 3:
 		 case 4:
-			delay = -(objects[booktype].oc_level - 1) *
+			context.spbook.delay = -(objects[booktype].oc_level - 1) *
 				objects[booktype].oc_delay;
 			break;
 		 case 5:
 		 case 6:
-			delay = -objects[booktype].oc_level *
+			context.spbook.delay = -objects[booktype].oc_level *
 				objects[booktype].oc_delay;
 			break;
 		 case 7:
-			delay = -8 * objects[booktype].oc_delay;
+			context.spbook.delay = -8 * objects[booktype].oc_delay;
 			break;
 		 default:
 			impossible("Unknown spellbook level %d, book %d;",
@@ -463,8 +463,8 @@ register struct obj *spellbook;
 		if (too_hard) {
 		    boolean gone = cursed_book(spellbook);
 
-		    nomul(delay);			/* study time */
-		    delay = 0;
+		    nomul(context.spbook.delay);			/* study time */
+		    context.spbook.delay = 0;
 		    if(gone || !rn2(3)) {
 			if (!gone) pline_The("spellbook crumbles to dust!");
 			if (!objects[spellbook->otyp].oc_name_known &&
@@ -478,8 +478,8 @@ register struct obj *spellbook;
 		    if (!confused_book(spellbook)) {
 			spellbook->in_use = FALSE;
 		    }
-		    nomul(delay);
-		    delay = 0;
+		    nomul(context.spbook.delay);
+		    context.spbook.delay = 0;
 		    return(1);
 		}
 		spellbook->in_use = FALSE;
@@ -489,7 +489,9 @@ register struct obj *spellbook;
 		    "memorize");
 	}
 
-	book = spellbook;
+	context.spbook.book = spellbook;
+	if (context.spbook.book)
+		context.spbook.o_id = context.spbook.book->o_id;
 	set_occupation(learn, "studying", 0);
 	return(1);
 }
@@ -500,7 +502,10 @@ void
 book_disappears(obj)
 struct obj *obj;
 {
-	if (obj == book) book = (struct obj *)0;
+	if (obj == context.spbook.book) {
+		context.spbook.book = (struct obj *)0;
+		context.spbook.o_id = 0;
+	}
 }
 
 /* renaming an object usually results in it having a different address;
@@ -510,7 +515,11 @@ void
 book_substitution(old_obj, new_obj)
 struct obj *old_obj, *new_obj;
 {
-	if (old_obj == book) book = new_obj;
+	if (old_obj == context.spbook.book) {
+		context.spbook.book = new_obj;
+		if (context.spbook.book)
+			context.spbook.o_id = context.spbook.book->o_id;
+	}
 }
 
 /* called from moveloop() */
@@ -1005,7 +1014,8 @@ losespells()
 	boolean confused = (Confusion != 0);
 	int  n, nzap, i;
 
-	book = 0;
+	context.spbook.book = 0;
+	context.spbook.o_id = 0;
 	for (n = 0; n < MAXSPELL && spellid(n) != NO_SPELL; n++)
 		continue;
 	if (n) {