using 'lastfree == NULL' to signal that table is using the dummy

node for its hash part + new macro 'allocsizenode'

1 files changed, 23 insertions, 23 deletions

diff --git a/ltable.c b/ltable.c
index 03318a5d..92c165ad 100644
--- a/ltable.c
+++ b/ltable.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltable.c,v 2.116 2015/11/03 18:35:21 roberto Exp roberto $
+** $Id: ltable.c,v 2.117 2015/11/19 19:16:22 roberto Exp roberto $
 ** Lua tables (hash)
 ** See Copyright Notice in lua.h
 */
@@ -74,8 +74,6 @@
 
 #define dummynode               (&dummynode_)
 
-#define isdummy(n)              ((n) == dummynode)
-
 static const Node dummynode_ = {
   {NILCONSTANT},  /* value */
   {{NILCONSTANT, 0}}  /* key */
@@ -308,14 +306,14 @@ static void setarrayvector (lua_State *L, Table *t, unsigned int size) {
 
 
 static void setnodevector (lua_State *L, Table *t, unsigned int size) {
-  int lsize;
   if (size == 0) {  /* no elements to hash part? */
     t->node = cast(Node *, dummynode);  /* use common 'dummynode' */
-    lsize = 0;
+    t->lsizenode = 0;
+    t->lastfree = NULL;  /* signal that it is using dummy node */
   }
   else {
     int i;
-    lsize = luaO_ceillog2(size);
+    int lsize = luaO_ceillog2(size);
     if (lsize > MAXHBITS)
       luaG_runerror(L, "table overflow");
     size = twoto(lsize);
@@ -326,9 +324,9 @@ static void setnodevector (lua_State *L, Table *t, unsigned int size) {
       setnilvalue(wgkey(n));
       setnilvalue(gval(n));
     }
+    t->lsizenode = cast_byte(lsize);
+    t->lastfree = gnode(t, size);  /* all positions are free */
   }
-  t->lsizenode = cast_byte(lsize);
-  t->lastfree = gnode(t, size);  /* all positions are free */
 }
 
 
@@ -337,7 +335,7 @@ void luaH_resize (lua_State *L, Table *t, unsigned int nasize,
   unsigned int i;
   int j;
   unsigned int oldasize = t->sizearray;
-  int oldhsize = t->lsizenode;
+  int oldhsize = allocsizenode(t);
   Node *nold = t->node;  /* save old hash ... */
   if (nasize > oldasize)  /* array part must grow? */
     setarrayvector(L, t, nasize);
@@ -354,7 +352,7 @@ void luaH_resize (lua_State *L, Table *t, unsigned int nasize,
     luaM_reallocvector(L, t->array, oldasize, nasize, TValue);
   }
   /* re-insert elements from hash part */
-  for (j = twoto(oldhsize) - 1; j >= 0; j--) {
+  for (j = oldhsize - 1; j >= 0; j--) {
     Node *old = nold + j;
     if (!ttisnil(gval(old))) {
       /* doesn't need barrier/invalidate cache, as entry was
@@ -362,13 +360,13 @@ void luaH_resize (lua_State *L, Table *t, unsigned int nasize,
       setobjt2t(L, luaH_set(L, t, gkey(old)), gval(old));
     }
   }
-  if (!isdummy(nold))
-    luaM_freearray(L, nold, cast(size_t, twoto(oldhsize))); /* free old hash */
+  if (oldhsize > 0)  /* not the dummy node? */
+    luaM_freearray(L, nold, cast(size_t, oldhsize)); /* free old hash */
 }
 
 
 void luaH_resizearray (lua_State *L, Table *t, unsigned int nasize) {
-  int nsize = isdummy(t->node) ? 0 : sizenode(t);
+  int nsize = allocsizenode(t);
   luaH_resize(L, t, nasize, nsize);
 }
 
@@ -414,7 +412,7 @@ Table *luaH_new (lua_State *L) {
 
 
 void luaH_free (lua_State *L, Table *t) {
-  if (!isdummy(t->node))
+  if (!isdummy(t))
     luaM_freearray(L, t->node, cast(size_t, sizenode(t)));
   luaM_freearray(L, t->array, t->sizearray);
   luaM_free(L, t);
@@ -422,10 +420,12 @@ void luaH_free (lua_State *L, Table *t) {
 
 
 static Node *getfreepos (Table *t) {
-  while (t->lastfree > t->node) {
-    t->lastfree--;
-    if (ttisnil(gkey(t->lastfree)))
-      return t->lastfree;
+  if (!isdummy(t)) {
+    while (t->lastfree > t->node) {
+      t->lastfree--;
+      if (ttisnil(gkey(t->lastfree)))
+        return t->lastfree;
+    }
   }
   return NULL;  /* could not find a free place */
 }
@@ -445,7 +445,7 @@ TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
   if (ttisnil(key)) luaG_runerror(L, "table index is nil");
   else if (ttisfloat(key)) {
     lua_Integer k;
-    if (luaV_tointeger(key, &k, 0)) {  /* index is int? */
+    if (luaV_tointeger(key, &k, 0)) {  /* does index fit in an integer? */
       setivalue(&aux, k);
       key = &aux;  /* insert it as an integer */
     }
@@ -453,7 +453,7 @@ TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
       luaG_runerror(L, "table index is NaN");
   }
   mp = mainposition(t, key);
-  if (!ttisnil(gval(mp)) || isdummy(mp)) {  /* main position is taken? */
+  if (!ttisnil(gval(mp)) || isdummy(t)) {  /* main position is taken? */
     Node *othern;
     Node *f = getfreepos(t);  /* get a free place */
     if (f == NULL) {  /* cannot find a free place? */
@@ -461,7 +461,7 @@ TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
       /* whatever called 'newkey' takes care of TM cache */
       return luaH_set(L, t, key);  /* insert key into grown table */
     }
-    lua_assert(!isdummy(f));
+    lua_assert(!isdummy(t));
     othern = mainposition(t, gkey(mp));
     if (othern != mp) {  /* is colliding node out of its main position? */
       /* yes; move colliding node into free position */
@@ -651,7 +651,7 @@ int luaH_getn (Table *t) {
     return i;
   }
   /* else must find a boundary in hash part */
-  else if (isdummy(t->node))  /* hash part is empty? */
+  else if (isdummy(t))  /* hash part is empty? */
     return j;  /* that is easy... */
   else return unbound_search(t, j);
 }
@@ -664,6 +664,6 @@ Node *luaH_mainposition (const Table *t, const TValue *key) {
   return mainposition(t, key);
 }
 
-int luaH_isdummy (Node *n) { return isdummy(n); }
+int luaH_isdummy (const Table *t) { return isdummy(t); }
 
 #endif