1 files changed, 103 insertions, 10 deletions

diff --git a/src/backend/access/gist/gistproc.c b/src/backend/access/gist/gistproc.c
index cb34b26113..43c4b1251b 100644
--- a/src/backend/access/gist/gistproc.c
+++ b/src/backend/access/gist/gistproc.c
@@ -6,11 +6,11 @@
  * This gives R-tree behavior, with Guttman's poly-time split algorithm.
  *
  *
- * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	$PostgreSQL: pgsql/src/backend/access/gist/gistproc.c,v 1.21 2010/02/26 02:00:33 momjian Exp $
+ *	src/backend/access/gist/gistproc.c
  *
  *-------------------------------------------------------------------------
  */
@@ -380,12 +380,12 @@ gist_box_picksplit(PG_FUNCTION_ARGS)
 	for (i = OffsetNumberNext(FirstOffsetNumber); i <= maxoff; i = OffsetNumberNext(i))
 	{
 		cur = DatumGetBoxP(entryvec->vector[i].key);
-		if (allisequal == true && (
-								   pageunion.high.x != cur->high.x ||
-								   pageunion.high.y != cur->high.y ||
-								   pageunion.low.x != cur->low.x ||
-								   pageunion.low.y != cur->low.y
-								   ))
+		if (allisequal && (
+						   pageunion.high.x != cur->high.x ||
+						   pageunion.high.y != cur->high.y ||
+						   pageunion.low.x != cur->low.x ||
+						   pageunion.low.y != cur->low.y
+						   ))
 			allisequal = false;
 
 		adjustBox(&pageunion, cur);
@@ -904,6 +904,76 @@ gist_point_compress(PG_FUNCTION_ARGS)
 	PG_RETURN_POINTER(entry);
 }
 
+#define point_point_distance(p1,p2) \
+	DatumGetFloat8(DirectFunctionCall2(point_distance, \
+									   PointPGetDatum(p1), PointPGetDatum(p2)))
+
+static double
+computeDistance(bool isLeaf, BOX *box, Point *point)
+{
+	double		result = 0.0;
+
+	if (isLeaf)
+	{
+		/* simple point to point distance */
+		result = point_point_distance(point, &box->low);
+	}
+	else if (point->x <= box->high.x && point->x >= box->low.x &&
+			 point->y <= box->high.y && point->y >= box->low.y)
+	{
+		/* point inside the box */
+		result = 0.0;
+	}
+	else if (point->x <= box->high.x && point->x >= box->low.x)
+	{
+		/* point is over or below box */
+		Assert(box->low.y <= box->high.y);
+		if (point->y > box->high.y)
+			result = point->y - box->high.y;
+		else if (point->y < box->low.y)
+			result = box->low.y - point->y;
+		else
+			elog(ERROR, "inconsistent point values");
+	}
+	else if (point->y <= box->high.y && point->y >= box->low.y)
+	{
+		/* point is to left or right of box */
+		Assert(box->low.x <= box->high.x);
+		if (point->x > box->high.x)
+			result = point->x - box->high.x;
+		else if (point->x < box->low.x)
+			result = box->low.x - point->x;
+		else
+			elog(ERROR, "inconsistent point values");
+	}
+	else
+	{
+		/* closest point will be a vertex */
+		Point		p;
+		double		subresult;
+
+		result = point_point_distance(point, &box->low);
+
+		subresult = point_point_distance(point, &box->high);
+		if (result > subresult)
+			result = subresult;
+
+		p.x = box->low.x;
+		p.y = box->high.y;
+		subresult = point_point_distance(point, &p);
+		if (result > subresult)
+			result = subresult;
+
+		p.x = box->high.x;
+		p.y = box->low.y;
+		subresult = point_point_distance(point, &p);
+		if (result > subresult)
+			result = subresult;
+	}
+
+	return result;
+}
+
 static bool
 gist_point_consistent_internal(StrategyNumber strategy,
 							   bool isLeaf, BOX *key, Point *query)
@@ -954,8 +1024,8 @@ gist_point_consistent(PG_FUNCTION_ARGS)
 {
 	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
-	bool		result;
 	bool	   *recheck = (bool *) PG_GETARG_POINTER(4);
+	bool		result;
 	StrategyNumber strategyGroup = strategy / GeoStrategyNumberOffset;
 
 	switch (strategyGroup)
@@ -1034,9 +1104,32 @@ gist_point_consistent(PG_FUNCTION_ARGS)
 			}
 			break;
 		default:
-			result = false;		/* silence compiler warning */
 			elog(ERROR, "unknown strategy number: %d", strategy);
+			result = false;		/* keep compiler quiet */
 	}
 
 	PG_RETURN_BOOL(result);
 }
+
+Datum
+gist_point_distance(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
+	double		distance;
+	StrategyNumber strategyGroup = strategy / GeoStrategyNumberOffset;
+
+	switch (strategyGroup)
+	{
+		case PointStrategyNumberGroup:
+			distance = computeDistance(GIST_LEAF(entry),
+									   DatumGetBoxP(entry->key),
+									   PG_GETARG_POINT_P(1));
+			break;
+		default:
+			elog(ERROR, "unknown strategy number: %d", strategy);
+			distance = 0.0;		/* keep compiler quiet */
+	}
+
+	PG_RETURN_FLOAT8(distance);
+}