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Use memcmp() rather than strncmp() when shorter string length is known.

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It appears that this will be faster for all but the shortest strings;
at least one some platforms, memcmp() can use word-at-a-time comparisons.

Noah Misch, somewhat pared down.
This commit is contained in:
Robert Haas
2010-12-21 22:11:40 -05:00
parent c5160b7eec
commit 32ba2b5160
7 changed files with 33 additions and 33 deletions
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8
contrib/hstore/hstore_io.c
View File

@ -280,9 +280,9 @@ comparePairs(const void *a, const void *b)
{
if (((Pairs *) a)->keylen == ((Pairs *) b)->keylen)
{
int res = strncmp(((Pairs *) a)->key,
((Pairs *) b)->key,
((Pairs *) a)->keylen);
int res = memcmp(((Pairs *) a)->key,
((Pairs *) b)->key,
((Pairs *) a)->keylen);
if (res)
return res;
@ -324,7 +324,7 @@ hstoreUniquePairs(Pairs *a, int4 l, int4 *buflen)
while (ptr - a < l)
{
if (ptr->keylen == res->keylen &&
strncmp(ptr->key, res->key, res->keylen) == 0)
memcmp(ptr->key, res->key, res->keylen) == 0)
{
if (ptr->needfree)
{

26
contrib/hstore/hstore_op.c
View File

@ -49,7 +49,7 @@ hstoreFindKey(HStore *hs, int *lowbound, char *key, int keylen)
stopMiddle = stopLow + (stopHigh - stopLow) / 2;
if (HS_KEYLEN(entries, stopMiddle) == keylen)
difference = strncmp(HS_KEY(entries, base, stopMiddle), key, keylen);
difference = memcmp(HS_KEY(entries, base, stopMiddle), key, keylen);
else
difference = (HS_KEYLEN(entries, stopMiddle) > keylen) ? 1 : -1;
@ -263,7 +263,7 @@ hstore_delete(PG_FUNCTION_ARGS)
int len = HS_KEYLEN(es, i);
char *ptrs = HS_KEY(es, bufs, i);
if (!(len == keylen && strncmp(ptrs, keyptr, keylen) == 0))
if (!(len == keylen && memcmp(ptrs, keyptr, keylen) == 0))
{
int vallen = HS_VALLEN(es, i);
@ -331,9 +331,9 @@ hstore_delete_array(PG_FUNCTION_ARGS)
int skeylen = HS_KEYLEN(es, i);
if (skeylen == key_pairs[j].keylen)
difference = strncmp(HS_KEY(es, ps, i),
key_pairs[j].key,
key_pairs[j].keylen);
difference = memcmp(HS_KEY(es, ps, i),
key_pairs[j].key,
key_pairs[j].keylen);
else
difference = (skeylen > key_pairs[j].keylen) ? 1 : -1;
}
@ -416,9 +416,9 @@ hstore_delete_hstore(PG_FUNCTION_ARGS)
int s2keylen = HS_KEYLEN(es2, j);
if (skeylen == s2keylen)
difference = strncmp(HS_KEY(es, ps, i),
HS_KEY(es2, ps2, j),
skeylen);
difference = memcmp(HS_KEY(es, ps, i),
HS_KEY(es2, ps2, j),
skeylen);
else
difference = (skeylen > s2keylen) ? 1 : -1;
}
@ -433,7 +433,7 @@ hstore_delete_hstore(PG_FUNCTION_ARGS)
if (snullval != HS_VALISNULL(es2, j)
|| (!snullval
&& (svallen != HS_VALLEN(es2, j)
|| strncmp(HS_VAL(es, ps, i), HS_VAL(es2, ps2, j), svallen) != 0)))
|| memcmp(HS_VAL(es, ps, i), HS_VAL(es2, ps2, j), svallen) != 0)))
{
HS_COPYITEM(ed, bufd, pd,
HS_KEY(es, ps, i), HS_KEYLEN(es, i),
@ -526,9 +526,9 @@ hstore_concat(PG_FUNCTION_ARGS)
int s2keylen = HS_KEYLEN(es2, s2idx);
if (s1keylen == s2keylen)
difference = strncmp(HS_KEY(es1, ps1, s1idx),
HS_KEY(es2, ps2, s2idx),
s1keylen);
difference = memcmp(HS_KEY(es1, ps1, s1idx),
HS_KEY(es2, ps2, s2idx),
s1keylen);
else
difference = (s1keylen > s2keylen) ? 1 : -1;
}
@ -996,7 +996,7 @@ hstore_contains(PG_FUNCTION_ARGS)
if (nullval != HS_VALISNULL(ve, idx)
|| (!nullval
&& (vallen != HS_VALLEN(ve, idx)
|| strncmp(HS_VAL(te, tstr, i), HS_VAL(ve, vstr, idx), vallen))))
|| memcmp(HS_VAL(te, tstr, i), HS_VAL(ve, vstr, idx), vallen))))
res = false;
}
else

2
contrib/ltree/ltree_gist.c
View File

@ -546,7 +546,7 @@ gist_tqcmp(ltree *t, lquery *q)
while (an > 0 && bn > 0)
{
bl = LQL_FIRST(ql);
if ((res = strncmp(al->name, bl->name, Min(al->len, bl->len))) == 0)
if ((res = memcmp(al->name, bl->name, Min(al->len, bl->len))) == 0)
{
if (al->len != bl->len)
return al->len - bl->len;

8
contrib/ltree/ltree_op.c
View File

@ -68,7 +68,7 @@ ltree_compare(const ltree *a, const ltree *b)
while (an > 0 && bn > 0)
{
if ((res = strncmp(al->name, bl->name, Min(al->len, bl->len))) == 0)
if ((res = memcmp(al->name, bl->name, Min(al->len, bl->len))) == 0)
{
if (al->len != bl->len)
return (al->len - bl->len) * 10 * (an + 1);
@ -165,7 +165,7 @@ inner_isparent(const ltree *c, const ltree *p)
{
if (cl->len != pl->len)
return false;
if (strncmp(cl->name, pl->name, cl->len))
if (memcmp(cl->name, pl->name, cl->len))
return false;
pn--;
@ -373,7 +373,7 @@ ltree_index(PG_FUNCTION_ARGS)
bptr = LTREE_FIRST(b);
for (j = 0; j < b->numlevel; j++)
{
if (!(aptr->len == bptr->len && strncmp(aptr->name, bptr->name, aptr->len) == 0))
if (!(aptr->len == bptr->len && memcmp(aptr->name, bptr->name, aptr->len) == 0))
break;
aptr = LEVEL_NEXT(aptr);
bptr = LEVEL_NEXT(bptr);
@ -451,7 +451,7 @@ lca_inner(ltree **a, int len)
num = 0;
for (i = 0; i < Min(tmp, (*ptr)->numlevel - 1); i++)
{
if (l1->len == l2->len && strncmp(l1->name, l2->name, l1->len) == 0)
if (l1->len == l2->len && memcmp(l1->name, l2->name, l1->len) == 0)
num = i + 1;
else
break;