Clean up some spell-related code

Add two helper functions and use those outside of spell.c,
instead of iterating through all the spells.

include/extern.h

@@ -2536,6 +2536,8 @@ extern int tport_spell(int);
 extern void losespells(void);
 extern int dovspell(void);
 extern void initialspell(struct obj *);
+extern boolean known_spell(short);
+extern int spell_idx(short);
 
 /* ### steal.c ### */
 

src/apply.c

@@ -1761,15 +1761,8 @@ jump(int magic) /* 0=Physical, otherwise skill level */
     coord cc;
 
     /* attempt "jumping" spell if hero has no innate jumping ability */
-    if (!magic && !Jumping) {
+    if (!magic && !Jumping && known_spell(SPE_JUMPING))
-        int sp_no;
+        return spelleffects(spell_idx(SPE_JUMPING), FALSE);
-
-        for (sp_no = 0; sp_no < MAXSPELL; ++sp_no)
-            if (g.spl_book[sp_no].sp_id == NO_SPELL)
-                break;
-            else if (g.spl_book[sp_no].sp_id == SPE_JUMPING)
-                return spelleffects(sp_no, FALSE);
-    }
 
     if (!magic && (nolimbs(g.youmonst.data) || slithy(g.youmonst.data))) {
         /* normally (nolimbs || slithy) implies !Jumping,

src/pray.c

@@ -760,7 +760,6 @@ gcrownu(void)
     struct obj *obj;
     boolean already_exists, in_hand;
     short class_gift;
-    int sp_no;
 #define ok_wep(o) ((o) && ((o)->oclass == WEAPON_CLASS || is_weptool(o)))
 
     HSee_invisible |= FROMOUTSIDE;
@@ -829,12 +828,8 @@ gcrownu(void)
         u.ugifts++;
         /* when getting a new book for known spell, enhance
            currently wielded weapon rather than the book */
-        for (sp_no = 0; sp_no < MAXSPELL; sp_no++)
+        if (known_spell(class_gift) && ok_wep(uwep))
-            if (g.spl_book[sp_no].sp_id == class_gift) {
+            obj = uwep; /* to be blessed,&c */
-                if (ok_wep(uwep))
-                    obj = uwep; /* to be blessed,&c */
-                break;
-            }
     }
 
     switch (u.ualign.type) {
@@ -1189,17 +1184,14 @@ pleased(aligntyp g_align)
             /*FALLTHRU*/
         case 6: {
             struct obj *otmp;
-            int sp_no, trycnt = u.ulevel + 1;
+            int trycnt = u.ulevel + 1;
 
             /* not yet known spells given preference over already known ones;
                also, try to grant a spell for which there is a skill slot */
             otmp = mkobj(SPBOOK_no_NOVEL, TRUE);
             while (--trycnt > 0) {
                 if (otmp->otyp != SPE_BLANK_PAPER) {
-                    for (sp_no = 0; sp_no < MAXSPELL; sp_no++)
+                    if (!known_spell(otmp->otyp)
-                        if (g.spl_book[sp_no].sp_id == otmp->otyp)
-                            break;
-                    if (sp_no == MAXSPELL
                         && !P_RESTRICTED(spell_skilltype(otmp->otyp)))
                         break; /* usable, but not yet known */
                 } else {
@@ -2007,21 +1999,9 @@ doturn(void)
     int once, range, xlev;
 
     if (!Role_if(PM_CLERIC) && !Role_if(PM_KNIGHT)) {
-        /* Try to use the "turn undead" spell.
+        /* Try to use the "turn undead" spell. */
-         *
+        if (known_spell(SPE_TURN_UNDEAD))
-         * This used to be based on whether hero knows the name of the
+            return spelleffects(spell_idx(SPE_TURN_UNDEAD), FALSE);
-         * turn undead spellbook, but it's possible to know--and be able
-         * to cast--the spell while having lost the book ID to amnesia.
-         * (It also used to tell spelleffects() to cast at self?)
-         */
-        int sp_no;
-
-        for (sp_no = 0; sp_no < MAXSPELL; ++sp_no) {
-            if (g.spl_book[sp_no].sp_id == NO_SPELL)
-                break;
-            else if (g.spl_book[sp_no].sp_id == SPE_TURN_UNDEAD)
-                return spelleffects(sp_no, FALSE);
-        }
         You("don't know how to turn undead!");
         return ECMD_OK;
     }

src/spell.c

@@ -915,7 +915,7 @@ spelleffects(int spell, boolean atme)
      * (There's no duplication of messages; when the rejection takes
      * place in getspell(), we don't get called.)
      */
-    if (rejectcasting()) {
+    if ((spell < 0) || rejectcasting()) {
         return ECMD_OK; /* no time elapses */
     }
 
@@ -1923,4 +1923,28 @@ initialspell(struct obj* obj)
     return;
 }
 
+/* return TRUE if hero knows spell otyp, FALSE otherwise */
+boolean
+known_spell(short otyp)
+{
+    int i;
+
+    for (i = 0; (i < MAXSPELL) && (spellid(i) != NO_SPELL); i++)
+        if (spellid(i) == otyp)
+            return TRUE;
+    return FALSE;
+}
+
+/* return index for spell otyp, or -1 if not found */
+int
+spell_idx(short otyp)
+{
+    int i;
+
+    for (i = 0; (i < MAXSPELL) && (spellid(i) != NO_SPELL); i++)
+        if (spellid(i) == otyp)
+            return i;
+    return -1;
+}
+
 /*spell.c*/

src/teleport.c

@@ -701,19 +701,18 @@ dotele(
     }
     if (!trap && !break_the_rules) {
         boolean castit = FALSE;
-        register int sp_no = 0, energy = 0;
+        int energy = 0;
 
         if (!Teleportation || (u.ulevel < (Role_if(PM_WIZARD) ? 8 : 12)
                                && !can_teleport(g.youmonst.data))) {
             /* Try to use teleport away spell. */
-            for (sp_no = 0; sp_no < MAXSPELL; sp_no++)
+            boolean knownsp = known_spell(SPE_TELEPORT_AWAY);
-                if (g.spl_book[sp_no].sp_id == SPE_TELEPORT_AWAY)
+
-                    break;
             /* casting isn't inhibited by being Stunned (...it ought to be) */
-            castit = (sp_no < MAXSPELL && !Confusion);
+            castit = (knownsp && !Confusion);
             if (!castit && !break_the_rules) {
                 You("%s.",
-                    !Teleportation ? ((sp_no < MAXSPELL)
+                    !Teleportation ? (knownsp
                                         ? "can't cast that spell"
                                         : "don't know that spell")
                                    : "are not able to teleport at will");
@@ -764,7 +763,7 @@ dotele(
         if (castit) {
             /* energy cost is deducted in spelleffects() */
             exercise(A_WIS, TRUE);
-            if ((spelleffects(sp_no, TRUE) & ECMD_TIME))
+            if ((spelleffects(spell_idx(SPE_TELEPORT_AWAY), TRUE) & ECMD_TIME))
                 return 1;
             else if (!break_the_rules)
                 return 0;