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Added "bulk operations" to arrays

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A few operations on arrays can be performed "in bulk", treating all
tags of a cell as a simple (or a few) word(s).
This commit is contained in:
Roberto Ierusalimschy
2024-03-15 11:01:34 -03:00
parent 52aa2b5d24
commit 3823fc6c81
3 changed files with 99 additions and 35 deletions
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57
ltable.c
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@@ -653,6 +653,44 @@ static void exchangehashpart (Table *t1, Table *t2) {
}
/*
** Re-insert into the new hash part of a table the elements from the
** vanishing slice of the array part.
*/
static void reinsertOldSlice (lua_State *L, Table *t, unsigned oldasize,
unsigned newasize) {
unsigned i;
t->alimit = newasize; /* pretend array has new size... */
for (i = newasize; i < oldasize; i++) { /* traverse vanishing slice */
int tag = *getArrTag(t, i);
if (!tagisempty(tag)) { /* a non-empty entry? */
TValue aux;
farr2val(t, i + 1, tag, &aux);
luaH_setint(L, t, i + 1, &aux); /* re-insert it into the table */
}
}
t->alimit = oldasize; /* restore current size... */
}
#define BK1(x) cast(lua_Unsigned, ((x) << 8) | LUA_VEMPTY)
/*
** Clear new slice of the array, in bulk.
*/
static void clearNewSlice (Table *t, unsigned oldasize, unsigned newasize) {
int i, j;
int firstcell = (oldasize + NM - 1) / NM;
int lastcell = cast_int((newasize + NM - 1) / NM) - 1;
for (i = firstcell; i <= lastcell; i++) {
/* empty tag repeated for all tags in a word */
const lua_Unsigned empty = BK1(BK1(BK1(BK1(BK1(BK1(BK1(BK1(0))))))));
for (j = 0; j < BKSZ; j++)
t->array[i].u.bulk[j] = empty;
}
}
/*
** Resize table 't' for the new given sizes. Both allocations (for
** the hash part and for the array part) can fail, which creates some
@@ -668,7 +706,6 @@ static void exchangehashpart (Table *t1, Table *t2) {
*/
void luaH_resize (lua_State *L, Table *t, unsigned int newasize,
unsigned int nhsize) {
unsigned int i;
Table newt; /* to keep the new hash part */
unsigned int oldasize = setlimittosize(t);
ArrayCell *newarray;
@@ -678,19 +715,10 @@ void luaH_resize (lua_State *L, Table *t, unsigned int newasize,
newt.flags = 0;
setnodevector(L, &newt, nhsize);
if (newasize < oldasize) { /* will array shrink? */
t->alimit = newasize; /* pretend array has new size... */
exchangehashpart(t, &newt); /* and new hash */
/* re-insert into the new hash the elements from vanishing slice */
for (i = newasize; i < oldasize; i++) {
int tag = *getArrTag(t, i);
if (!tagisempty(tag)) { /* a non-empty entry? */
TValue aux;
farr2val(t, i + 1, tag, &aux);
luaH_setint(L, t, i + 1, &aux);
}
}
t->alimit = oldasize; /* restore current size... */
exchangehashpart(t, &newt); /* and hash (in case of errors) */
exchangehashpart(t, &newt); /* pretend table has new hash */
reinsertOldSlice(L, t, oldasize, newasize);
exchangehashpart(t, &newt); /* restore old hash (in case of errors) */
}
/* allocate new array */
newarray = resizearray(L, t, oldasize, newasize);
@@ -702,8 +730,7 @@ void luaH_resize (lua_State *L, Table *t, unsigned int newasize,
exchangehashpart(t, &newt); /* 't' has the new hash ('newt' has the old) */
t->array = newarray; /* set new array part */
t->alimit = newasize;
for (i = oldasize; i < newasize; i++) /* clear new slice of the array */
*getArrTag(t, i) = LUA_VEMPTY;
clearNewSlice(t, oldasize, newasize);
/* re-insert elements from old hash part into new parts */
reinsert(L, &newt, t); /* 'newt' now has the old hash */
freehash(L, &newt); /* free old hash part */