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Refactor table traversal.

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Sponsored by OpenResty Inc.
This commit is contained in:
Mike Pall
2021-09-19 17:38:49 +02:00
parent 4e0ea654a8
commit c6f5ef649b
12 changed files with 156 additions and 210 deletions
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62
src/lj_tab.c
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@@ -568,56 +568,66 @@ TValue *lj_tab_set(lua_State *L, GCtab *t, cTValue *key)
/* -- Table traversal ----------------------------------------------------- */
/* Get the traversal index of a key. */
static uint32_t keyindex(lua_State *L, GCtab *t, cTValue *key)
/* Table traversal indexes:
**
** Array key index: [0 .. t->asize-1]
** Hash key index: [t->asize .. t->asize+t->hmask]
** Invalid key: ~0
*/
/* Get the successor traversal index of a key. */
uint32_t LJ_FASTCALL lj_tab_keyindex(GCtab *t, cTValue *key)
{
TValue tmp;
if (tvisint(key)) {
int32_t k = intV(key);
if ((uint32_t)k < t->asize)
return (uint32_t)k; /* Array key indexes: [0..t->asize-1] */
return (uint32_t)k + 1;
setnumV(&tmp, (lua_Number)k);
key = &tmp;
} else if (tvisnum(key)) {
lua_Number nk = numV(key);
int32_t k = lj_num2int(nk);
if ((uint32_t)k < t->asize && nk == (lua_Number)k)
return (uint32_t)k; /* Array key indexes: [0..t->asize-1] */
return (uint32_t)k + 1;
}
if (!tvisnil(key)) {
Node *n = hashkey(t, key);
do {
if (lj_obj_equal(&n->key, key))
return t->asize + (uint32_t)(n - noderef(t->node));
/* Hash key indexes: [t->asize..t->asize+t->nmask] */
return t->asize + (uint32_t)((n+1) - noderef(t->node));
} while ((n = nextnode(n)));
if (key->u32.hi == 0xfffe7fff) /* ITERN was despecialized while running. */
return key->u32.lo - 1;
lj_err_msg(L, LJ_ERR_NEXTIDX);
return 0; /* unreachable */
if (key->u32.hi == LJ_KEYINDEX) /* Despecialized ITERN while running. */
return key->u32.lo;
return ~0u; /* Invalid key to next. */
}
return ~0u; /* A nil key starts the traversal. */
return 0; /* A nil key starts the traversal. */
}
/* Advance to the next step in a table traversal. */
int lj_tab_next(lua_State *L, GCtab *t, TValue *key)
/* Get the next key/value pair of a table traversal. */
int lj_tab_next(GCtab *t, cTValue *key, TValue *o)
{
uint32_t i = keyindex(L, t, key); /* Find predecessor key index. */
for (i++; i < t->asize; i++) /* First traverse the array keys. */
if (!tvisnil(arrayslot(t, i))) {
setintV(key, i);
copyTV(L, key+1, arrayslot(t, i));
return 1;
}
for (i -= t->asize; i <= t->hmask; i++) { /* Then traverse the hash keys. */
Node *n = &noderef(t->node)[i];
if (!tvisnil(&n->val)) {
copyTV(L, key, &n->key);
copyTV(L, key+1, &n->val);
uint32_t idx = lj_tab_keyindex(t, key); /* Find successor index of key. */
/* First traverse the array part. */
for (; idx < t->asize; idx++) {
cTValue *a = arrayslot(t, idx);
if (LJ_LIKELY(!tvisnil(a))) {
setintV(o, idx);
o[1] = *a;
return 1;
}
}
return 0; /* End of traversal. */
idx -= t->asize;
/* Then traverse the hash part. */
for (; idx <= t->hmask; idx++) {
Node *n = &noderef(t->node)[idx];
if (!tvisnil(&n->val)) {
o[0] = n->key;
o[1] = n->val;
return 1;
}
}
return (int32_t)idx < 0 ? -1 : 0; /* Invalid key or end of traversal. */
}
/* -- Table length calculation -------------------------------------------- */