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

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.

diff --git a/contrib/hstore/hstore_io.c b/contrib/hstore/hstore_io.c
index 0058f5c1b3f15a5336b06e3b7da82aeeed4620a4..0d6f0b6b138b7947009ad9295d5731adec17d33f 100644 (file)
--- a/contrib/hstore/hstore_io.c
+++ b/contrib/hstore/hstore_io.c
@@ -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)
            {

diff --git a/contrib/hstore/hstore_op.c b/contrib/hstore/hstore_op.c
index 8d73a463aba1f4f0155d0f00e3f2740db6d2a1aa..93d8cbcaebb6301334f941bfba033009c01fca7c 100644 (file)
--- a/contrib/hstore/hstore_op.c
+++ b/contrib/hstore/hstore_op.c
@@ -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

diff --git a/contrib/ltree/ltree_gist.c b/contrib/ltree/ltree_gist.c
index 5fa7b59d32d824e981978cb7d329b65f74aca453..47a85bbabc2002f60a342b6ce001bc8420c79720 100644 (file)
--- a/contrib/ltree/ltree_gist.c
+++ b/contrib/ltree/ltree_gist.c
@@ -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;

diff --git a/contrib/ltree/ltree_op.c b/contrib/ltree/ltree_op.c
index 2ddfdec7eb14e610c625ddba16915b319c163185..2b048d4b7c5f84979a32df5160b20e1d20f6bd79 100644 (file)
--- a/contrib/ltree/ltree_op.c
+++ b/contrib/ltree/ltree_op.c
@@ -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;

diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 933d58ada5f59fddbbc0224c9a6f5c6748726b8c..d0d0b1cfe394151f0cb9fa0db76c1337ccc63bd1 100644 (file)
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -1196,7 +1196,7 @@ parseNodeString(void)
    token = pg_strtok(&length);
 
 #define MATCH(tokname, namelen) \
-   (length == namelen && strncmp(token, tokname, namelen) == 0)
+   (length == namelen && memcmp(token, tokname, namelen) == 0)
 
    if (MATCH("QUERY", 5))
        return_value = _readQuery();

diff --git a/src/backend/utils/adt/varchar.c b/src/backend/utils/adt/varchar.c
index 34acfb36180f4a1feef82075c07b67ec2313719f..b3d7ba3f403805ac581ad3b3f1830da42ab7a8b8 100644 (file)
--- a/src/backend/utils/adt/varchar.c
+++ b/src/backend/utils/adt/varchar.c
@@ -690,7 +690,7 @@ bpchareq(PG_FUNCTION_ARGS)
    if (len1 != len2)
        result = false;
    else
-       result = (strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), len1) == 0);
+       result = (memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), len1) == 0);
 
    PG_FREE_IF_COPY(arg1, 0);
    PG_FREE_IF_COPY(arg2, 1);
@@ -717,7 +717,7 @@ bpcharne(PG_FUNCTION_ARGS)
    if (len1 != len2)
        result = true;
    else
-       result = (strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), len1) != 0);
+       result = (memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), len1) != 0);
 
    PG_FREE_IF_COPY(arg1, 0);
    PG_FREE_IF_COPY(arg2, 1);
@@ -905,7 +905,7 @@ internal_bpchar_pattern_compare(BpChar *arg1, BpChar *arg2)
    len1 = bcTruelen(arg1);
    len2 = bcTruelen(arg2);
 
-   result = strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), Min(len1, len2));
+   result = memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), Min(len1, len2));
    if (result != 0)
        return result;
    else if (len1 < len2)

diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index ee83e2f30886a6160e82a13700af4005941f6b0d..2fa740ac8c013889685eaaefee5ff96c6d97f844 100644 (file)
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1286,7 +1286,7 @@ varstr_cmp(char *arg1, int len1, char *arg2, int len2)
     */
    if (lc_collate_is_c())
    {
-       result = strncmp(arg1, arg2, Min(len1, len2));
+       result = memcmp(arg1, arg2, Min(len1, len2));
        if ((result == 0) && (len1 != len2))
            result = (len1 < len2) ? -1 : 1;
    }
@@ -1370,7 +1370,7 @@ varstr_cmp(char *arg1, int len1, char *arg2, int len2)
             */
            if (result == 0)
            {
-               result = strncmp(arg1, arg2, Min(len1, len2));
+               result = memcmp(arg1, arg2, Min(len1, len2));
                if ((result == 0) && (len1 != len2))
                    result = (len1 < len2) ? -1 : 1;
            }
@@ -1462,8 +1462,8 @@ texteq(PG_FUNCTION_ARGS)
    if (VARSIZE_ANY_EXHDR(arg1) != VARSIZE_ANY_EXHDR(arg2))
        result = false;
    else
-       result = (strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2),
-                         VARSIZE_ANY_EXHDR(arg1)) == 0);
+       result = (memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2),
+                        VARSIZE_ANY_EXHDR(arg1)) == 0);
 
    PG_FREE_IF_COPY(arg1, 0);
    PG_FREE_IF_COPY(arg2, 1);
@@ -1485,8 +1485,8 @@ textne(PG_FUNCTION_ARGS)
    if (VARSIZE_ANY_EXHDR(arg1) != VARSIZE_ANY_EXHDR(arg2))
        result = true;
    else
-       result = (strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2),
-                         VARSIZE_ANY_EXHDR(arg1)) != 0);
+       result = (memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2),
+                        VARSIZE_ANY_EXHDR(arg1)) != 0);
 
    PG_FREE_IF_COPY(arg1, 0);
    PG_FREE_IF_COPY(arg2, 1);
@@ -1612,7 +1612,7 @@ internal_text_pattern_compare(text *arg1, text *arg2)
    len1 = VARSIZE_ANY_EXHDR(arg1);
    len2 = VARSIZE_ANY_EXHDR(arg2);
 
-   result = strncmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), Min(len1, len2));
+   result = memcmp(VARDATA_ANY(arg1), VARDATA_ANY(arg2), Min(len1, len2));
    if (result != 0)
        return result;
    else if (len1 < len2)