/*
* Inet histogram partial match divider calculation
*
* First the families and the lengths of the network parts are compared using
* the subnet inclusion operator. If those are acceptable for the operator,
* the divider will be calculated using the masklens and the common bits of
* the addresses. -1 will be returned if it cannot be calculated.
*
* See commentary for inet_hist_value_sel() for some rationale for this.
*/
static int
inet_hist_match_divider(inet *boundary, inet *query, int opr_codenum)
{
if (ip_family(boundary) == ip_family(query) &&
inet_masklen_inclusion_cmp(boundary, query, opr_codenum) == 0)
{
int min_bits,
decisive_bits;
min_bits = Min(ip_bits(boundary), ip_bits(query));
/*
* Set decisive_bits to the masklen of the one that should contain the
* other according to the operator.
*/
if (opr_codenum < 0)
decisive_bits = ip_bits(boundary);
else if (opr_codenum > 0)
decisive_bits = ip_bits(query);
else
decisive_bits = min_bits;
/*
* Now return the number of non-common decisive bits. (This will be
* zero if the boundary and query in fact match, else positive.)
*/
if (min_bits > 0)
return decisive_bits - bitncommon(ip_addr(boundary),
ip_addr(query),
min_bits);
return decisive_bits;
}
return -1;
}
/*
* The SP-GiST choose function
*/
Datum
inet_spg_choose(PG_FUNCTION_ARGS)
{
spgChooseIn *in = (spgChooseIn *) PG_GETARG_POINTER(0);
spgChooseOut *out = (spgChooseOut *) PG_GETARG_POINTER(1);
inet *val = DatumGetInetPP(in->datum),
*prefix;
int commonbits;
/*
* If we're looking at a tuple that splits by address family, choose the
* appropriate subnode.
*/
if (!in->hasPrefix)
{
/* allTheSame isn't possible for such a tuple */
Assert(!in->allTheSame);
Assert(in->nNodes == 2);
out->resultType = spgMatchNode;
out->result.matchNode.nodeN = (ip_family(val) == PGSQL_AF_INET) ? 0 : 1;
out->result.matchNode.restDatum = InetPGetDatum(val);
PG_RETURN_VOID();
}
/* Else it must split by prefix */
Assert(in->nNodes == 4 || in->allTheSame);
prefix = DatumGetInetPP(in->prefixDatum);
commonbits = ip_bits(prefix);
/*
* We cannot put addresses from different families under the same inner
* node, so we have to split if the new value's family is different.
*/
if (ip_family(val) != ip_family(prefix))
{
/* Set up 2-node tuple */
out->resultType = spgSplitTuple;
out->result.splitTuple.prefixHasPrefix = false;
out->result.splitTuple.prefixNNodes = 2;
out->result.splitTuple.prefixNodeLabels = NULL;
/* Identify which node the existing data goes into */
out->result.splitTuple.childNodeN =
(ip_family(prefix) == PGSQL_AF_INET) ? 0 : 1;
out->result.splitTuple.postfixHasPrefix = true;
out->result.splitTuple.postfixPrefixDatum = InetPGetDatum(prefix);
PG_RETURN_VOID();
}
/*
* If the new value does not match the existing prefix, we have to split.
*/
if (ip_bits(val) < commonbits ||
bitncmp(ip_addr(prefix), ip_addr(val), commonbits) != 0)
{
/* Determine new prefix length for the split tuple */
commonbits = bitncommon(ip_addr(prefix), ip_addr(val),
Min(ip_bits(val), commonbits));
/* Set up 4-node tuple */
out->resultType = spgSplitTuple;
out->result.splitTuple.prefixHasPrefix = true;
out->result.splitTuple.prefixPrefixDatum =
InetPGetDatum(cidr_set_masklen_internal(val, commonbits));
out->result.splitTuple.prefixNNodes = 4;
out->result.splitTuple.prefixNodeLabels = NULL;
/* Identify which node the existing data goes into */
out->result.splitTuple.childNodeN =
inet_spg_node_number(prefix, commonbits);
out->result.splitTuple.postfixHasPrefix = true;
out->result.splitTuple.postfixPrefixDatum = InetPGetDatum(prefix);
PG_RETURN_VOID();
}
/*
* All OK, choose the node to descend into. (If this tuple is marked
* allTheSame, the core code will ignore our choice of nodeN; but we need
* not account for that case explicitly here.)
*/
out->resultType = spgMatchNode;
out->result.matchNode.nodeN = inet_spg_node_number(val, commonbits);
out->result.matchNode.restDatum = InetPGetDatum(val);
PG_RETURN_VOID();
}
/*
* The GiST PickSplit method
*/
Datum
inet_spg_picksplit(PG_FUNCTION_ARGS)
{
spgPickSplitIn *in = (spgPickSplitIn *) PG_GETARG_POINTER(0);
spgPickSplitOut *out = (spgPickSplitOut *) PG_GETARG_POINTER(1);
inet *prefix,
*tmp;
int i,
commonbits;
bool differentFamilies = false;
/* Initialize the prefix with the first item */
prefix = DatumGetInetPP(in->datums[0]);
commonbits = ip_bits(prefix);
/* Examine remaining items to discover minimum common prefix length */
for (i = 1; i < in->nTuples; i++)
{
tmp = DatumGetInetPP(in->datums[i]);
if (ip_family(tmp) != ip_family(prefix))
{
differentFamilies = true;
break;
}
if (ip_bits(tmp) < commonbits)
commonbits = ip_bits(tmp);
commonbits = bitncommon(ip_addr(prefix), ip_addr(tmp), commonbits);
if (commonbits == 0)
break;
}
/* Don't need labels; allocate output arrays */
out->nodeLabels = NULL;
out->mapTuplesToNodes = (int *) palloc(sizeof(int) * in->nTuples);
out->leafTupleDatums = (Datum *) palloc(sizeof(Datum) * in->nTuples);
if (differentFamilies)
{
/* Set up 2-node tuple */
out->hasPrefix = false;
out->nNodes = 2;
for (i = 0; i < in->nTuples; i++)
{
tmp = DatumGetInetPP(in->datums[i]);
out->mapTuplesToNodes[i] =
(ip_family(tmp) == PGSQL_AF_INET) ? 0 : 1;
out->leafTupleDatums[i] = InetPGetDatum(tmp);
}
}
else
{
/* Set up 4-node tuple */
out->hasPrefix = true;
out->prefixDatum =
InetPGetDatum(cidr_set_masklen_internal(prefix, commonbits));
out->nNodes = 4;
for (i = 0; i < in->nTuples; i++)
{
tmp = DatumGetInetPP(in->datums[i]);
out->mapTuplesToNodes[i] = inet_spg_node_number(tmp, commonbits);
out->leafTupleDatums[i] = InetPGetDatum(tmp);
}
}
PG_RETURN_VOID();
}