Tsearch2 functionality migrates to core. The bulk of this work is by

Oleg Bartunov and Teodor Sigaev, but I did a lot of editorializing,
so anything that's broken is probably my fault.

Documentation is nonexistent as yet, but let's land the patch so we can
get some portability testing done.

1 files changed, 259 insertions, 0 deletions

diff --git a/src/backend/utils/adt/tsquery_gist.c b/src/backend/utils/adt/tsquery_gist.c
new file mode 100644
index 00000000000..0deca10075c
--- /dev/null
+++ b/src/backend/utils/adt/tsquery_gist.c
@@ -0,0 +1,259 @@
+/*-------------------------------------------------------------------------
+ *
+ * tsquery_gist.c
+ *	  GiST index support for tsquery
+ *
+ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/tsquery_gist.c,v 1.1 2007/08/21 01:11:19 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/skey.h"
+#include "access/gist.h"
+#include "tsearch/ts_type.h"
+#include "tsearch/ts_utils.h"
+
+#define GETENTRY(vec,pos) ((TSQuerySign *) DatumGetPointer((vec)->vector[(pos)].key))
+
+Datum
+gtsquery_compress(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	GISTENTRY  *retval = entry;
+
+	if (entry->leafkey)
+	{
+		TSQuerySign *sign = (TSQuerySign *) palloc(sizeof(TSQuerySign));
+
+		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
+		*sign = makeTSQuerySign(DatumGetTSQuery(entry->key));
+
+		gistentryinit(*retval, PointerGetDatum(sign),
+					  entry->rel, entry->page,
+					  entry->offset, FALSE);
+	}
+
+	PG_RETURN_POINTER(retval);
+}
+
+Datum
+gtsquery_decompress(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_DATUM(PG_GETARG_DATUM(0));
+}
+
+Datum
+gtsquery_consistent(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	TSQuerySign *key = (TSQuerySign *) DatumGetPointer(entry->key);
+	TSQuery		query = PG_GETARG_TSQUERY(1);
+	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
+	TSQuerySign sq = makeTSQuerySign(query);
+	bool		retval;
+
+	switch (strategy)
+	{
+		case RTContainsStrategyNumber:
+			if (GIST_LEAF(entry))
+				retval = (*key & sq) == sq;
+			else
+				retval = (*key & sq) != 0;
+			break;
+		case RTContainedByStrategyNumber:
+			if (GIST_LEAF(entry))
+				retval = (*key & sq) == *key;
+			else
+				retval = (*key & sq) != 0;
+			break;
+		default:
+			retval = FALSE;
+	}
+	PG_RETURN_BOOL(retval);
+}
+
+Datum
+gtsquery_union(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	int		   *size = (int *) PG_GETARG_POINTER(1);
+	TSQuerySign *sign = (TSQuerySign *) palloc(sizeof(TSQuerySign));
+	int			i;
+
+	memset(sign, 0, sizeof(TSQuerySign));
+
+	for (i = 0; i < entryvec->n; i++)
+		*sign |= *GETENTRY(entryvec, i);
+
+	*size = sizeof(TSQuerySign);
+
+	PG_RETURN_POINTER(sign);
+}
+
+Datum
+gtsquery_same(PG_FUNCTION_ARGS)
+{
+	TSQuerySign *a = (TSQuerySign *) PG_GETARG_POINTER(0);
+	TSQuerySign *b = (TSQuerySign *) PG_GETARG_POINTER(1);
+
+	PG_RETURN_POINTER(*a == *b);
+}
+
+static int
+sizebitvec(TSQuerySign sign)
+{
+	int			size = 0,
+				i;
+
+	for (i = 0; i < TSQS_SIGLEN; i++)
+		size += 0x01 & (sign >> i);
+
+	return size;
+}
+
+static int
+hemdist(TSQuerySign a, TSQuerySign b)
+{
+	TSQuerySign res = a ^ b;
+
+	return sizebitvec(res);
+}
+
+Datum
+gtsquery_penalty(PG_FUNCTION_ARGS)
+{
+	TSQuerySign *origval = (TSQuerySign *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
+	TSQuerySign *newval = (TSQuerySign *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
+	float	   *penalty = (float *) PG_GETARG_POINTER(2);
+
+	*penalty = hemdist(*origval, *newval);
+
+	PG_RETURN_POINTER(penalty);
+}
+
+
+typedef struct
+{
+	OffsetNumber pos;
+	int4		cost;
+} SPLITCOST;
+
+static int
+comparecost(const void *a, const void *b)
+{
+	if (((SPLITCOST *) a)->cost == ((SPLITCOST *) b)->cost)
+		return 0;
+	else
+		return (((SPLITCOST *) a)->cost > ((SPLITCOST *) b)->cost) ? 1 : -1;
+}
+
+#define WISH_F(a,b,c) (double)( -(double)(((a)-(b))*((a)-(b))*((a)-(b)))*(c) )
+
+Datum
+gtsquery_picksplit(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
+	OffsetNumber maxoff = entryvec->n - 2;
+	OffsetNumber k,
+				j;
+
+	TSQuerySign *datum_l,
+			   *datum_r;
+	int4		size_alpha,
+				size_beta;
+	int4		size_waste,
+				waste = -1;
+	int4		nbytes;
+	OffsetNumber seed_1 = 0,
+				seed_2 = 0;
+	OffsetNumber *left,
+			   *right;
+
+	SPLITCOST  *costvector;
+
+	nbytes = (maxoff + 2) * sizeof(OffsetNumber);
+	left = v->spl_left = (OffsetNumber *) palloc(nbytes);
+	right = v->spl_right = (OffsetNumber *) palloc(nbytes);
+	v->spl_nleft = v->spl_nright = 0;
+
+	for (k = FirstOffsetNumber; k < maxoff; k = OffsetNumberNext(k))
+		for (j = OffsetNumberNext(k); j <= maxoff; j = OffsetNumberNext(j))
+		{
+			size_waste = hemdist(*GETENTRY(entryvec, j), *GETENTRY(entryvec, k));
+			if (size_waste > waste)
+			{
+				waste = size_waste;
+				seed_1 = k;
+				seed_2 = j;
+			}
+		}
+
+
+	if (seed_1 == 0 || seed_2 == 0)
+	{
+		seed_1 = 1;
+		seed_2 = 2;
+	}
+
+	datum_l = (TSQuerySign *) palloc(sizeof(TSQuerySign));
+	*datum_l = *GETENTRY(entryvec, seed_1);
+	datum_r = (TSQuerySign *) palloc(sizeof(TSQuerySign));
+	*datum_r = *GETENTRY(entryvec, seed_2);
+
+
+	maxoff = OffsetNumberNext(maxoff);
+	costvector = (SPLITCOST *) palloc(sizeof(SPLITCOST) * maxoff);
+	for (j = FirstOffsetNumber; j <= maxoff; j = OffsetNumberNext(j))
+	{
+		costvector[j - 1].pos = j;
+		size_alpha = hemdist(*GETENTRY(entryvec, seed_1), *GETENTRY(entryvec, j));
+		size_beta = hemdist(*GETENTRY(entryvec, seed_2), *GETENTRY(entryvec, j));
+		costvector[j - 1].cost = abs(size_alpha - size_beta);
+	}
+	qsort((void *) costvector, maxoff, sizeof(SPLITCOST), comparecost);
+
+	for (k = 0; k < maxoff; k++)
+	{
+		j = costvector[k].pos;
+		if (j == seed_1)
+		{
+			*left++ = j;
+			v->spl_nleft++;
+			continue;
+		}
+		else if (j == seed_2)
+		{
+			*right++ = j;
+			v->spl_nright++;
+			continue;
+		}
+		size_alpha = hemdist(*datum_l, *GETENTRY(entryvec, j));
+		size_beta = hemdist(*datum_r, *GETENTRY(entryvec, j));
+
+		if (size_alpha < size_beta + WISH_F(v->spl_nleft, v->spl_nright, 0.05))
+		{
+			*datum_l |= *GETENTRY(entryvec, j);
+			*left++ = j;
+			v->spl_nleft++;
+		}
+		else
+		{
+			*datum_r |= *GETENTRY(entryvec, j);
+			*right++ = j;
+			v->spl_nright++;
+		}
+	}
+
+	*right = *left = FirstOffsetNumber;
+	v->spl_ldatum = PointerGetDatum(datum_l);
+	v->spl_rdatum = PointerGetDatum(datum_r);
+
+	PG_RETURN_POINTER(v);
+}