/*
* Validity test for a new-format hstore.
* 0 = not valid
* 1 = valid but with "slop" in the length
* 2 = exactly valid
*/
static int
hstoreValidNewFormat(HStore *hs)
{
int count = HS_COUNT(hs);
HEntry *entries = ARRPTR(hs);
int buflen = (count) ? HSE_ENDPOS(entries[2 * (count) - 1]) : 0;
int vsize = CALCDATASIZE(count, buflen);
int i;
if (hs->size_ & HS_FLAG_NEWVERSION)
return 2;
if (count == 0)
return 2;
if (!HSE_ISFIRST(entries[0]))
return 0;
if (vsize > VARSIZE(hs))
return 0;
/* entry position must be nondecreasing */
for (i = 1; i < 2 * count; ++i)
{
if (HSE_ISFIRST(entries[i])
|| (HSE_ENDPOS(entries[i]) < HSE_ENDPOS(entries[i - 1])))
return 0;
}
/* key length must be nondecreasing and keys must not be null */
for (i = 1; i < count; ++i)
{
if (HS_KEYLEN(entries, i) < HS_KEYLEN(entries, i - 1))
return 0;
if (HSE_ISNULL(entries[2 * i]))
return 0;
}
if (vsize != VARSIZE(hs))
return 1;
return 2;
}
Datum
hstore_cmp(PG_FUNCTION_ARGS)
{
HStore *hs1 = PG_GETARG_HS(0);
HStore *hs2 = PG_GETARG_HS(1);
int hcount1 = HS_COUNT(hs1);
int hcount2 = HS_COUNT(hs2);
int res = 0;
if (hcount1 == 0 || hcount2 == 0)
{
/*
* if either operand is empty, and the other is nonempty, the nonempty
* one is larger. If both are empty they are equal.
*/
if (hcount1 > 0)
res = 1;
else if (hcount2 > 0)
res = -1;
}
else
{
/* here we know both operands are nonempty */
char *str1 = STRPTR(hs1);
char *str2 = STRPTR(hs2);
HEntry *ent1 = ARRPTR(hs1);
HEntry *ent2 = ARRPTR(hs2);
size_t len1 = HSE_ENDPOS(ent1[2 * hcount1 - 1]);
size_t len2 = HSE_ENDPOS(ent2[2 * hcount2 - 1]);
res = memcmp(str1, str2, Min(len1, len2));
if (res == 0)
{
if (len1 > len2)
res = 1;
else if (len1 < len2)
res = -1;
else if (hcount1 > hcount2)
res = 1;
else if (hcount2 > hcount1)
res = -1;
else
{
int count = hcount1 * 2;
int i;
for (i = 0; i < count; ++i)
if (HSE_ENDPOS(ent1[i]) != HSE_ENDPOS(ent2[i]) ||
HSE_ISNULL(ent1[i]) != HSE_ISNULL(ent2[i]))
break;
if (i < count)
{
if (HSE_ENDPOS(ent1[i]) < HSE_ENDPOS(ent2[i]))
res = -1;
else if (HSE_ENDPOS(ent1[i]) > HSE_ENDPOS(ent2[i]))
res = 1;
else if (HSE_ISNULL(ent1[i]))
res = 1;
else if (HSE_ISNULL(ent2[i]))
res = -1;
}
}
}
else
{
res = (res > 0) ? 1 : -1;
}
}
/*
* this is a btree support function; this is one of the few places where
* memory needs to be explicitly freed.
*/
PG_FREE_IF_COPY(hs1, 0);
PG_FREE_IF_COPY(hs2, 1);
PG_RETURN_INT32(res);
}
