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luaH_set does the set and protect its value; luaH_move can then be a

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macro.
New algorithm for double hashing (does not use "%").
This commit is contained in:
Roberto Ierusalimschy 1999-01-25 15:41:19 -02:00
parent 57ffc3f009
commit fd7d0774e5
1 changed files with 16 additions and 31 deletions
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47
ltable.c
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@ -1,5 +1,5 @@
/*
** $Id: ltable.c,v 1.18 1999/01/22 18:47:23 roberto Exp roberto $
** $Id: ltable.c,v 1.19 1999/01/25 12:30:11 roberto Exp roberto $
** Lua tables (hash)
** See Copyright Notice in lua.h
*/
@ -53,21 +53,17 @@ static long int hashindex (TObject *ref) {
}
Node *luaH_present (Hash *t, TObject *ref) {
Node *luaH_present (Hash *t, TObject *key) {
int tsize = nhash(t);
long int h = hashindex(ref);
long int h = hashindex(key);
int h1 = h%tsize;
Node *n = node(t, h1);
/* keep looking until an entry with "ref" equal to ref or nil */
if ((ttype(ref(n)) == ttype(ref) ? !luaO_equalval(ref, ref(n))
: ttype(ref(n)) != LUA_T_NIL)) {
int h2 = h%(tsize-2) + 1;
do {
h1 += h2;
if (h1 >= tsize) h1 -= tsize;
n = node(t, h1);
} while ((ttype(ref(n)) == ttype(ref) ? !luaO_equalval(ref, ref(n))
: ttype(ref(n)) != LUA_T_NIL));
/* keep looking until an entry with "ref" equal to key or nil */
while ((ttype(ref(n)) == ttype(key)) ? !luaO_equalval(key, ref(n))
: ttype(ref(n)) != LUA_T_NIL) {
h1 += (h&(tsize-2)) + 1; /* double hashing */
if (h1 >= tsize) h1 -= tsize;
n = node(t, h1);
}
return n;
}
@ -139,21 +135,20 @@ static void rehash (Hash *t) {
}
/*
** If the hash node is present, return its pointer, otherwise create a new
** node for the given reference and also return its pointer.
*/
TObject *luaH_set (Hash *t, TObject *ref) {
void luaH_set (Hash *t, TObject *ref, TObject *val) {
Node *n = luaH_present(t, ref);
if (ttype(ref(n)) == LUA_T_NIL) {
if (ttype(ref(n)) != LUA_T_NIL)
*val(n) = *val;
else {
TObject buff = *val; /* rehash may invalidate this address */
if ((long)nuse(t)*3L > (long)nhash(t)*2L) {
rehash(t);
n = luaH_present(t, ref);
}
nuse(t)++;
*ref(n) = *ref;
*val(n) = buff;
}
return (val(n));
}
@ -186,7 +181,7 @@ void luaH_setint (Hash *t, int ref, TObject *val) {
TObject index;
ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = ref;
*(luaH_set(t, &index)) = *val;
luaH_set(t, &index, val);
}
@ -197,13 +192,3 @@ TObject *luaH_getint (Hash *t, int ref) {
return luaH_get(t, &index);
}
void luaH_move (Hash *t, int from, int to) {
TObject index;
TObject *toadd;
ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = to;
toadd = luaH_set(t, &index);
nvalue(&index) = from;
*toadd = *luaH_get(t, &index);
}