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small optimizations

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This commit is contained in:
Roberto Ierusalimschy 2004-09-27 15:54:45 -03:00
parent b2820f39a2
commit 66845f415f
1 changed files with 8 additions and 13 deletions
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21
ltable.c
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@ -1,5 +1,5 @@
/* /*
** $Id: ltable.c,v 2.4 2004/08/10 19:17:23 roberto Exp roberto $ ** $Id: ltable.c,v 2.5 2004/08/31 17:57:33 roberto Exp roberto $
** Lua tables (hash) ** Lua tables (hash)
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -107,11 +107,10 @@ Node *luaH_mainposition (const Table *t, const TValue *key) {
** returns the index for `key' if `key' is an appropriate key to live in ** returns the index for `key' if `key' is an appropriate key to live in
** the array part of the table, -1 otherwise. ** the array part of the table, -1 otherwise.
*/ */
static int arrayindex (const TValue *key, lua_Number lim) { static int arrayindex (const TValue *key) {
if (ttisnumber(key)) { if (ttisnumber(key)) {
lua_Number n = nvalue(key); lua_Number n = nvalue(key);
int k; int k;
if (n <= 0 || n > lim) return -1; /* out of range? */
lua_number2int(k, n); lua_number2int(k, n);
if (cast(lua_Number, k) == nvalue(key)) if (cast(lua_Number, k) == nvalue(key))
return k; return k;
@ -128,10 +127,9 @@ static int arrayindex (const TValue *key, lua_Number lim) {
static int luaH_index (lua_State *L, Table *t, StkId key) { static int luaH_index (lua_State *L, Table *t, StkId key) {
int i; int i;
if (ttisnil(key)) return -1; /* first iteration */ if (ttisnil(key)) return -1; /* first iteration */
i = arrayindex(key, t->sizearray); i = arrayindex(key);
if (0 <= i) { /* is `key' inside array part? */ if (0 < i && i <= t->sizearray) /* is `key' inside array part? */
return i-1; /* yes; that's the index (corrected to C) */ return i-1; /* yes; that's the index (corrected to C) */
}
else { else {
const TValue *v = luaH_get(t, key); const TValue *v = luaH_get(t, key);
if (v == &luaO_nilobject) if (v == &luaO_nilobject)
@ -195,7 +193,6 @@ static void numuse (const Table *t, int *narray, int *nhash) {
int nums[MAXBITS+1]; int nums[MAXBITS+1];
int i, lg; int i, lg;
int totaluse = 0; int totaluse = 0;
lua_Number sizelimit; /* an upper bound for the array size */
/* count elements in array part */ /* count elements in array part */
for (i=0, lg=0; lg<=MAXBITS; lg++) { /* for each slice [2^(lg-1) to 2^lg) */ for (i=0, lg=0; lg<=MAXBITS; lg++) { /* for each slice [2^(lg-1) to 2^lg) */
int ttlg = twoto(lg); /* 2^lg */ int ttlg = twoto(lg); /* 2^lg */
@ -215,14 +212,11 @@ static void numuse (const Table *t, int *narray, int *nhash) {
*narray = totaluse; /* all previous uses were in array part */ *narray = totaluse; /* all previous uses were in array part */
/* count elements in hash part */ /* count elements in hash part */
i = sizenode(t); i = sizenode(t);
/* array part cannot be larger than twice the maximum number of elements */
sizelimit = cast(lua_Number, totaluse + i) * 2;
if (sizelimit >= MAXASIZE) sizelimit = MAXASIZE;
while (i--) { while (i--) {
Node *n = &t->node[i]; Node *n = &t->node[i];
if (!ttisnil(gval(n))) { if (!ttisnil(gval(n))) {
int k = arrayindex(gkey(n), sizelimit); int k = arrayindex(gkey(n));
if (k >= 0) { /* is `key' an appropriate array index? */ if (0 < k && k <= MAXASIZE) { /* is `key' an appropriate array index? */
nums[luaO_log2(k-1)+1]++; /* count as such */ nums[luaO_log2(k-1)+1]++; /* count as such */
(*narray)++; (*narray)++;
} }
@ -397,7 +391,8 @@ static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
** search function for integers ** search function for integers
*/ */
const TValue *luaH_getnum (Table *t, int key) { const TValue *luaH_getnum (Table *t, int key) {
if (1 <= key && key <= t->sizearray) /* (1 <= key && key <= t->sizearray) */
if ((unsigned int)(key-1) < (unsigned int)t->sizearray)
return &t->array[key-1]; return &t->array[key-1];
else { else {
lua_Number nk = cast(lua_Number, key); lua_Number nk = cast(lua_Number, key);