Adding upstream version 13.4.upstream/13.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 1096 insertions, 0 deletions

diff --git a/contrib/seg/seg.c b/contrib/seg/seg.c
new file mode 100644
index 0000000..4a8e2be
--- /dev/null
+++ b/contrib/seg/seg.c
@@ -0,0 +1,1090 @@
+/*
+ * contrib/seg/seg.c
+ *
+ ******************************************************************************
+  This file contains routines that can be bound to a Postgres backend and
+  called by the backend in the process of processing queries.  The calling
+  format for these routines is dictated by Postgres architecture.
+******************************************************************************/
+
+#include "postgres.h"
+
+#include <float.h>
+
+#include "access/gist.h"
+#include "access/stratnum.h"
+#include "fmgr.h"
+
+#include "segdata.h"
+
+
+#define DatumGetSegP(X) ((SEG *) DatumGetPointer(X))
+#define PG_GETARG_SEG_P(n) DatumGetSegP(PG_GETARG_DATUM(n))
+
+
+/*
+#define GIST_DEBUG
+#define GIST_QUERY_DEBUG
+*/
+
+PG_MODULE_MAGIC;
+
+/*
+ * Auxiliary data structure for picksplit method.
+ */
+typedef struct
+{
+	float		center;
+	OffsetNumber index;
+	SEG		   *data;
+} gseg_picksplit_item;
+
+/*
+** Input/Output routines
+*/
+PG_FUNCTION_INFO_V1(seg_in);
+PG_FUNCTION_INFO_V1(seg_out);
+PG_FUNCTION_INFO_V1(seg_size);
+PG_FUNCTION_INFO_V1(seg_lower);
+PG_FUNCTION_INFO_V1(seg_upper);
+PG_FUNCTION_INFO_V1(seg_center);
+
+/*
+** GiST support methods
+*/
+PG_FUNCTION_INFO_V1(gseg_consistent);
+PG_FUNCTION_INFO_V1(gseg_compress);
+PG_FUNCTION_INFO_V1(gseg_decompress);
+PG_FUNCTION_INFO_V1(gseg_picksplit);
+PG_FUNCTION_INFO_V1(gseg_penalty);
+PG_FUNCTION_INFO_V1(gseg_union);
+PG_FUNCTION_INFO_V1(gseg_same);
+static Datum gseg_leaf_consistent(Datum key, Datum query, StrategyNumber strategy);
+static Datum gseg_internal_consistent(Datum key, Datum query, StrategyNumber strategy);
+static Datum gseg_binary_union(Datum r1, Datum r2, int *sizep);
+
+
+/*
+** R-tree support functions
+*/
+PG_FUNCTION_INFO_V1(seg_same);
+PG_FUNCTION_INFO_V1(seg_contains);
+PG_FUNCTION_INFO_V1(seg_contained);
+PG_FUNCTION_INFO_V1(seg_overlap);
+PG_FUNCTION_INFO_V1(seg_left);
+PG_FUNCTION_INFO_V1(seg_over_left);
+PG_FUNCTION_INFO_V1(seg_right);
+PG_FUNCTION_INFO_V1(seg_over_right);
+PG_FUNCTION_INFO_V1(seg_union);
+PG_FUNCTION_INFO_V1(seg_inter);
+static void rt_seg_size(SEG *a, float *size);
+
+/*
+** Various operators
+*/
+PG_FUNCTION_INFO_V1(seg_cmp);
+PG_FUNCTION_INFO_V1(seg_lt);
+PG_FUNCTION_INFO_V1(seg_le);
+PG_FUNCTION_INFO_V1(seg_gt);
+PG_FUNCTION_INFO_V1(seg_ge);
+PG_FUNCTION_INFO_V1(seg_different);
+
+/*
+** Auxiliary functions
+*/
+static int	restore(char *s, float val, int n);
+
+
+/*****************************************************************************
+ * Input/Output functions
+ *****************************************************************************/
+
+Datum
+seg_in(PG_FUNCTION_ARGS)
+{
+	char	   *str = PG_GETARG_CSTRING(0);
+	SEG		   *result = palloc(sizeof(SEG));
+
+	seg_scanner_init(str);
+
+	if (seg_yyparse(result) != 0)
+		seg_yyerror(result, "bogus input");
+
+	seg_scanner_finish();
+
+	PG_RETURN_POINTER(result);
+}
+
+Datum
+seg_out(PG_FUNCTION_ARGS)
+{
+	SEG		   *seg = PG_GETARG_SEG_P(0);
+	char	   *result;
+	char	   *p;
+
+	p = result = (char *) palloc(40);
+
+	if (seg->l_ext == '>' || seg->l_ext == '<' || seg->l_ext == '~')
+		p += sprintf(p, "%c", seg->l_ext);
+
+	if (seg->lower == seg->upper && seg->l_ext == seg->u_ext)
+	{
+		/*
+		 * indicates that this interval was built by seg_in off a single point
+		 */
+		p += restore(p, seg->lower, seg->l_sigd);
+	}
+	else
+	{
+		if (seg->l_ext != '-')
+		{
+			/* print the lower boundary if exists */
+			p += restore(p, seg->lower, seg->l_sigd);
+			p += sprintf(p, " ");
+		}
+		p += sprintf(p, "..");
+		if (seg->u_ext != '-')
+		{
+			/* print the upper boundary if exists */
+			p += sprintf(p, " ");
+			if (seg->u_ext == '>' || seg->u_ext == '<' || seg->l_ext == '~')
+				p += sprintf(p, "%c", seg->u_ext);
+			p += restore(p, seg->upper, seg->u_sigd);
+		}
+	}
+
+	PG_RETURN_CSTRING(result);
+}
+
+Datum
+seg_center(PG_FUNCTION_ARGS)
+{
+	SEG		   *seg = PG_GETARG_SEG_P(0);
+
+	PG_RETURN_FLOAT4(((float) seg->lower + (float) seg->upper) / 2.0);
+}
+
+Datum
+seg_lower(PG_FUNCTION_ARGS)
+{
+	SEG		   *seg = PG_GETARG_SEG_P(0);
+
+	PG_RETURN_FLOAT4(seg->lower);
+}
+
+Datum
+seg_upper(PG_FUNCTION_ARGS)
+{
+	SEG		   *seg = PG_GETARG_SEG_P(0);
+
+	PG_RETURN_FLOAT4(seg->upper);
+}
+
+
+/*****************************************************************************
+ *						   GiST functions
+ *****************************************************************************/
+
+/*
+** The GiST Consistent method for segments
+** Should return false if for all data items x below entry,
+** the predicate x op query == false, where op is the oper
+** corresponding to strategy in the pg_amop table.
+*/
+Datum
+gseg_consistent(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	Datum		query = PG_GETARG_DATUM(1);
+	StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
+
+	/* Oid		subtype = PG_GETARG_OID(3); */
+	bool	   *recheck = (bool *) PG_GETARG_POINTER(4);
+
+	/* All cases served by this function are exact */
+	*recheck = false;
+
+	/*
+	 * if entry is not leaf, use gseg_internal_consistent, else use
+	 * gseg_leaf_consistent
+	 */
+	if (GIST_LEAF(entry))
+		return gseg_leaf_consistent(entry->key, query, strategy);
+	else
+		return gseg_internal_consistent(entry->key, query, strategy);
+}
+
+/*
+** The GiST Union method for segments
+** returns the minimal bounding seg that encloses all the entries in entryvec
+*/
+Datum
+gseg_union(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	int		   *sizep = (int *) PG_GETARG_POINTER(1);
+	int			numranges,
+				i;
+	Datum		out = 0;
+	Datum		tmp;
+
+#ifdef GIST_DEBUG
+	fprintf(stderr, "union\n");
+#endif
+
+	numranges = entryvec->n;
+	tmp = entryvec->vector[0].key;
+	*sizep = sizeof(SEG);
+
+	for (i = 1; i < numranges; i++)
+	{
+		out = gseg_binary_union(tmp, entryvec->vector[i].key, sizep);
+		tmp = out;
+	}
+
+	PG_RETURN_DATUM(out);
+}
+
+/*
+** GiST Compress and Decompress methods for segments
+** do not do anything.
+*/
+Datum
+gseg_compress(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_POINTER(PG_GETARG_POINTER(0));
+}
+
+Datum
+gseg_decompress(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_POINTER(PG_GETARG_POINTER(0));
+}
+
+/*
+** The GiST Penalty method for segments
+** As in the R-tree paper, we use change in area as our penalty metric
+*/
+Datum
+gseg_penalty(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *origentry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	GISTENTRY  *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
+	float	   *result = (float *) PG_GETARG_POINTER(2);
+	SEG		   *ud;
+	float		tmp1,
+				tmp2;
+
+	ud = DatumGetSegP(DirectFunctionCall2(seg_union,
+										  origentry->key,
+										  newentry->key));
+	rt_seg_size(ud, &tmp1);
+	rt_seg_size(DatumGetSegP(origentry->key), &tmp2);
+	*result = tmp1 - tmp2;
+
+#ifdef GIST_DEBUG
+	fprintf(stderr, "penalty\n");
+	fprintf(stderr, "\t%g\n", *result);
+#endif
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+ * Compare function for gseg_picksplit_item: sort by center.
+ */
+static int
+gseg_picksplit_item_cmp(const void *a, const void *b)
+{
+	const gseg_picksplit_item *i1 = (const gseg_picksplit_item *) a;
+	const gseg_picksplit_item *i2 = (const gseg_picksplit_item *) b;
+
+	if (i1->center < i2->center)
+		return -1;
+	else if (i1->center == i2->center)
+		return 0;
+	else
+		return 1;
+}
+
+/*
+ * The GiST PickSplit method for segments
+ *
+ * We used to use Guttman's split algorithm here, but since the data is 1-D
+ * it's easier and more robust to just sort the segments by center-point and
+ * split at the middle.
+ */
+Datum
+gseg_picksplit(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
+	int			i;
+	SEG		   *seg,
+			   *seg_l,
+			   *seg_r;
+	gseg_picksplit_item *sort_items;
+	OffsetNumber *left,
+			   *right;
+	OffsetNumber maxoff;
+	OffsetNumber firstright;
+
+#ifdef GIST_DEBUG
+	fprintf(stderr, "picksplit\n");
+#endif
+
+	/* Valid items in entryvec->vector[] are indexed 1..maxoff */
+	maxoff = entryvec->n - 1;
+
+	/*
+	 * Prepare the auxiliary array and sort it.
+	 */
+	sort_items = (gseg_picksplit_item *)
+		palloc(maxoff * sizeof(gseg_picksplit_item));
+	for (i = 1; i <= maxoff; i++)
+	{
+		seg = DatumGetSegP(entryvec->vector[i].key);
+		/* center calculation is done this way to avoid possible overflow */
+		sort_items[i - 1].center = seg->lower * 0.5f + seg->upper * 0.5f;
+		sort_items[i - 1].index = i;
+		sort_items[i - 1].data = seg;
+	}
+	qsort(sort_items, maxoff, sizeof(gseg_picksplit_item),
+		  gseg_picksplit_item_cmp);
+
+	/* sort items below "firstright" will go into the left side */
+	firstright = maxoff / 2;
+
+	v->spl_left = (OffsetNumber *) palloc(maxoff * sizeof(OffsetNumber));
+	v->spl_right = (OffsetNumber *) palloc(maxoff * sizeof(OffsetNumber));
+	left = v->spl_left;
+	v->spl_nleft = 0;
+	right = v->spl_right;
+	v->spl_nright = 0;
+
+	/*
+	 * Emit segments to the left output page, and compute its bounding box.
+	 */
+	seg_l = (SEG *) palloc(sizeof(SEG));
+	memcpy(seg_l, sort_items[0].data, sizeof(SEG));
+	*left++ = sort_items[0].index;
+	v->spl_nleft++;
+	for (i = 1; i < firstright; i++)
+	{
+		Datum		sortitem = PointerGetDatum(sort_items[i].data);
+
+		seg_l = DatumGetSegP(DirectFunctionCall2(seg_union,
+												 PointerGetDatum(seg_l),
+												 sortitem));
+		*left++ = sort_items[i].index;
+		v->spl_nleft++;
+	}
+
+	/*
+	 * Likewise for the right page.
+	 */
+	seg_r = (SEG *) palloc(sizeof(SEG));
+	memcpy(seg_r, sort_items[firstright].data, sizeof(SEG));
+	*right++ = sort_items[firstright].index;
+	v->spl_nright++;
+	for (i = firstright + 1; i < maxoff; i++)
+	{
+		Datum		sortitem = PointerGetDatum(sort_items[i].data);
+
+		seg_r = DatumGetSegP(DirectFunctionCall2(seg_union,
+												 PointerGetDatum(seg_r),
+												 sortitem));
+		*right++ = sort_items[i].index;
+		v->spl_nright++;
+	}
+
+	v->spl_ldatum = PointerGetDatum(seg_l);
+	v->spl_rdatum = PointerGetDatum(seg_r);
+
+	PG_RETURN_POINTER(v);
+}
+
+/*
+** Equality methods
+*/
+Datum
+gseg_same(PG_FUNCTION_ARGS)
+{
+	bool	   *result = (bool *) PG_GETARG_POINTER(2);
+
+	if (DirectFunctionCall2(seg_same, PG_GETARG_DATUM(0), PG_GETARG_DATUM(1)))
+		*result = true;
+	else
+		*result = false;
+
+#ifdef GIST_DEBUG
+	fprintf(stderr, "same: %s\n", (*result ? "TRUE" : "FALSE"));
+#endif
+
+	PG_RETURN_POINTER(result);
+}
+
+/*
+** SUPPORT ROUTINES
+*/
+static Datum
+gseg_leaf_consistent(Datum key, Datum query, StrategyNumber strategy)
+{
+	Datum		retval;
+
+#ifdef GIST_QUERY_DEBUG
+	fprintf(stderr, "leaf_consistent, %d\n", strategy);
+#endif
+
+	switch (strategy)
+	{
+		case RTLeftStrategyNumber:
+			retval = DirectFunctionCall2(seg_left, key, query);
+			break;
+		case RTOverLeftStrategyNumber:
+			retval = DirectFunctionCall2(seg_over_left, key, query);
+			break;
+		case RTOverlapStrategyNumber:
+			retval = DirectFunctionCall2(seg_overlap, key, query);
+			break;
+		case RTOverRightStrategyNumber:
+			retval = DirectFunctionCall2(seg_over_right, key, query);
+			break;
+		case RTRightStrategyNumber:
+			retval = DirectFunctionCall2(seg_right, key, query);
+			break;
+		case RTSameStrategyNumber:
+			retval = DirectFunctionCall2(seg_same, key, query);
+			break;
+		case RTContainsStrategyNumber:
+		case RTOldContainsStrategyNumber:
+			retval = DirectFunctionCall2(seg_contains, key, query);
+			break;
+		case RTContainedByStrategyNumber:
+		case RTOldContainedByStrategyNumber:
+			retval = DirectFunctionCall2(seg_contained, key, query);
+			break;
+		default:
+			retval = false;
+	}
+
+	PG_RETURN_DATUM(retval);
+}
+
+static Datum
+gseg_internal_consistent(Datum key, Datum query, StrategyNumber strategy)
+{
+	bool		retval;
+
+#ifdef GIST_QUERY_DEBUG
+	fprintf(stderr, "internal_consistent, %d\n", strategy);
+#endif
+
+	switch (strategy)
+	{
+		case RTLeftStrategyNumber:
+			retval =
+				!DatumGetBool(DirectFunctionCall2(seg_over_right, key, query));
+			break;
+		case RTOverLeftStrategyNumber:
+			retval =
+				!DatumGetBool(DirectFunctionCall2(seg_right, key, query));
+			break;
+		case RTOverlapStrategyNumber:
+			retval =
+				DatumGetBool(DirectFunctionCall2(seg_overlap, key, query));
+			break;
+		case RTOverRightStrategyNumber:
+			retval =
+				!DatumGetBool(DirectFunctionCall2(seg_left, key, query));
+			break;
+		case RTRightStrategyNumber:
+			retval =
+				!DatumGetBool(DirectFunctionCall2(seg_over_left, key, query));
+			break;
+		case RTSameStrategyNumber:
+		case RTContainsStrategyNumber:
+		case RTOldContainsStrategyNumber:
+			retval =
+				DatumGetBool(DirectFunctionCall2(seg_contains, key, query));
+			break;
+		case RTContainedByStrategyNumber:
+		case RTOldContainedByStrategyNumber:
+			retval =
+				DatumGetBool(DirectFunctionCall2(seg_overlap, key, query));
+			break;
+		default:
+			retval = false;
+	}
+
+	PG_RETURN_BOOL(retval);
+}
+
+static Datum
+gseg_binary_union(Datum r1, Datum r2, int *sizep)
+{
+	Datum		retval;
+
+	retval = DirectFunctionCall2(seg_union, r1, r2);
+	*sizep = sizeof(SEG);
+
+	return retval;
+}
+
+
+Datum
+seg_contains(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL((a->lower <= b->lower) && (a->upper >= b->upper));
+}
+
+Datum
+seg_contained(PG_FUNCTION_ARGS)
+{
+	Datum		a = PG_GETARG_DATUM(0);
+	Datum		b = PG_GETARG_DATUM(1);
+
+	PG_RETURN_DATUM(DirectFunctionCall2(seg_contains, b, a));
+}
+
+/*****************************************************************************
+ * Operator class for R-tree indexing
+ *****************************************************************************/
+
+Datum
+seg_same(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp == 0);
+}
+
+/*	seg_overlap -- does a overlap b?
+ */
+Datum
+seg_overlap(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL(((a->upper >= b->upper) && (a->lower <= b->upper)) ||
+				   ((b->upper >= a->upper) && (b->lower <= a->upper)));
+}
+
+/*	seg_over_left -- is the right edge of (a) located at or left of the right edge of (b)?
+ */
+Datum
+seg_over_left(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL(a->upper <= b->upper);
+}
+
+/*	seg_left -- is (a) entirely on the left of (b)?
+ */
+Datum
+seg_left(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL(a->upper < b->lower);
+}
+
+/*	seg_right -- is (a) entirely on the right of (b)?
+ */
+Datum
+seg_right(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL(a->lower > b->upper);
+}
+
+/*	seg_over_right -- is the left edge of (a) located at or right of the left edge of (b)?
+ */
+Datum
+seg_over_right(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	PG_RETURN_BOOL(a->lower >= b->lower);
+}
+
+Datum
+seg_union(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+	SEG		   *n;
+
+	n = (SEG *) palloc(sizeof(*n));
+
+	/* take max of upper endpoints */
+	if (a->upper > b->upper)
+	{
+		n->upper = a->upper;
+		n->u_sigd = a->u_sigd;
+		n->u_ext = a->u_ext;
+	}
+	else
+	{
+		n->upper = b->upper;
+		n->u_sigd = b->u_sigd;
+		n->u_ext = b->u_ext;
+	}
+
+	/* take min of lower endpoints */
+	if (a->lower < b->lower)
+	{
+		n->lower = a->lower;
+		n->l_sigd = a->l_sigd;
+		n->l_ext = a->l_ext;
+	}
+	else
+	{
+		n->lower = b->lower;
+		n->l_sigd = b->l_sigd;
+		n->l_ext = b->l_ext;
+	}
+
+	PG_RETURN_POINTER(n);
+}
+
+Datum
+seg_inter(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+	SEG		   *n;
+
+	n = (SEG *) palloc(sizeof(*n));
+
+	/* take min of upper endpoints */
+	if (a->upper < b->upper)
+	{
+		n->upper = a->upper;
+		n->u_sigd = a->u_sigd;
+		n->u_ext = a->u_ext;
+	}
+	else
+	{
+		n->upper = b->upper;
+		n->u_sigd = b->u_sigd;
+		n->u_ext = b->u_ext;
+	}
+
+	/* take max of lower endpoints */
+	if (a->lower > b->lower)
+	{
+		n->lower = a->lower;
+		n->l_sigd = a->l_sigd;
+		n->l_ext = a->l_ext;
+	}
+	else
+	{
+		n->lower = b->lower;
+		n->l_sigd = b->l_sigd;
+		n->l_ext = b->l_ext;
+	}
+
+	PG_RETURN_POINTER(n);
+}
+
+static void
+rt_seg_size(SEG *a, float *size)
+{
+	if (a == (SEG *) NULL || a->upper <= a->lower)
+		*size = 0.0;
+	else
+		*size = (float) Abs(a->upper - a->lower);
+}
+
+Datum
+seg_size(PG_FUNCTION_ARGS)
+{
+	SEG		   *seg = PG_GETARG_SEG_P(0);
+
+	PG_RETURN_FLOAT4((float) Abs(seg->upper - seg->lower));
+}
+
+
+/*****************************************************************************
+ *				   Miscellaneous operators
+ *****************************************************************************/
+Datum
+seg_cmp(PG_FUNCTION_ARGS)
+{
+	SEG		   *a = PG_GETARG_SEG_P(0);
+	SEG		   *b = PG_GETARG_SEG_P(1);
+
+	/*
+	 * First compare on lower boundary position
+	 */
+	if (a->lower < b->lower)
+		PG_RETURN_INT32(-1);
+	if (a->lower > b->lower)
+		PG_RETURN_INT32(1);
+
+	/*
+	 * a->lower == b->lower, so consider type of boundary.
+	 *
+	 * A '-' lower bound is < any other kind (this could only be relevant if
+	 * -HUGE_VAL is used as a regular data value). A '<' lower bound is < any
+	 * other kind except '-'. A '>' lower bound is > any other kind.
+	 */
+	if (a->l_ext != b->l_ext)
+	{
+		if (a->l_ext == '-')
+			PG_RETURN_INT32(-1);
+		if (b->l_ext == '-')
+			PG_RETURN_INT32(1);
+		if (a->l_ext == '<')
+			PG_RETURN_INT32(-1);
+		if (b->l_ext == '<')
+			PG_RETURN_INT32(1);
+		if (a->l_ext == '>')
+			PG_RETURN_INT32(1);
+		if (b->l_ext == '>')
+			PG_RETURN_INT32(-1);
+	}
+
+	/*
+	 * For other boundary types, consider # of significant digits first.
+	 */
+	if (a->l_sigd < b->l_sigd)	/* (a) is blurred and is likely to include (b) */
+		PG_RETURN_INT32(-1);
+	if (a->l_sigd > b->l_sigd)	/* (a) is less blurred and is likely to be
+								 * included in (b) */
+		PG_RETURN_INT32(1);
+
+	/*
+	 * For same # of digits, an approximate boundary is more blurred than
+	 * exact.
+	 */
+	if (a->l_ext != b->l_ext)
+	{
+		if (a->l_ext == '~')	/* (a) is approximate, while (b) is exact */
+			PG_RETURN_INT32(-1);
+		if (b->l_ext == '~')
+			PG_RETURN_INT32(1);
+		/* can't get here unless data is corrupt */
+		elog(ERROR, "bogus lower boundary types %d %d",
+			 (int) a->l_ext, (int) b->l_ext);
+	}
+
+	/* at this point, the lower boundaries are identical */
+
+	/*
+	 * First compare on upper boundary position
+	 */
+	if (a->upper < b->upper)
+		PG_RETURN_INT32(-1);
+	if (a->upper > b->upper)
+		PG_RETURN_INT32(1);
+
+	/*
+	 * a->upper == b->upper, so consider type of boundary.
+	 *
+	 * A '-' upper bound is > any other kind (this could only be relevant if
+	 * HUGE_VAL is used as a regular data value). A '<' upper bound is < any
+	 * other kind. A '>' upper bound is > any other kind except '-'.
+	 */
+	if (a->u_ext != b->u_ext)
+	{
+		if (a->u_ext == '-')
+			PG_RETURN_INT32(1);
+		if (b->u_ext == '-')
+			PG_RETURN_INT32(-1);
+		if (a->u_ext == '<')
+			PG_RETURN_INT32(-1);
+		if (b->u_ext == '<')
+			PG_RETURN_INT32(1);
+		if (a->u_ext == '>')
+			PG_RETURN_INT32(1);
+		if (b->u_ext == '>')
+			PG_RETURN_INT32(-1);
+	}
+
+	/*
+	 * For other boundary types, consider # of significant digits first. Note
+	 * result here is converse of the lower-boundary case.
+	 */
+	if (a->u_sigd < b->u_sigd)	/* (a) is blurred and is likely to include (b) */
+		PG_RETURN_INT32(1);
+	if (a->u_sigd > b->u_sigd)	/* (a) is less blurred and is likely to be
+								 * included in (b) */
+		PG_RETURN_INT32(-1);
+
+	/*
+	 * For same # of digits, an approximate boundary is more blurred than
+	 * exact.  Again, result is converse of lower-boundary case.
+	 */
+	if (a->u_ext != b->u_ext)
+	{
+		if (a->u_ext == '~')	/* (a) is approximate, while (b) is exact */
+			PG_RETURN_INT32(1);
+		if (b->u_ext == '~')
+			PG_RETURN_INT32(-1);
+		/* can't get here unless data is corrupt */
+		elog(ERROR, "bogus upper boundary types %d %d",
+			 (int) a->u_ext, (int) b->u_ext);
+	}
+
+	PG_RETURN_INT32(0);
+}
+
+Datum
+seg_lt(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp < 0);
+}
+
+Datum
+seg_le(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp <= 0);
+}
+
+Datum
+seg_gt(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp > 0);
+}
+
+Datum
+seg_ge(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp >= 0);
+}
+
+
+Datum
+seg_different(PG_FUNCTION_ARGS)
+{
+	int			cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
+														PG_GETARG_DATUM(0),
+														PG_GETARG_DATUM(1)));
+
+	PG_RETURN_BOOL(cmp != 0);
+}
+
+
+
+/*****************************************************************************
+ *				   Auxiliary functions
+ *****************************************************************************/
+
+/*
+ * The purpose of this routine is to print the given floating point
+ * value with exactly n significant digits.  Its behaviour
+ * is similar to %.ng except it prints 8.00 where %.ng would
+ * print 8.  Returns the length of the string written at "result".
+ *
+ * Caller must provide a sufficiently large result buffer; 16 bytes
+ * should be enough for all known float implementations.
+ */
+static int
+restore(char *result, float val, int n)
+{
+	char		buf[25] = {
+		'0', '0', '0', '0', '0',
+		'0', '0', '0', '0', '0',
+		'0', '0', '0', '0', '0',
+		'0', '0', '0', '0', '0',
+		'0', '0', '0', '0', '\0'
+	};
+	char	   *p;
+	int			exp;
+	int			i,
+				dp,
+				sign;
+
+	/*
+	 * Put a cap on the number of significant digits to avoid garbage in the
+	 * output and ensure we don't overrun the result buffer.
+	 */
+	n = Min(n, FLT_DIG);
+
+	/* remember the sign */
+	sign = (val < 0 ? 1 : 0);
+
+	/* print, in %e style to start with */
+	sprintf(result, "%.*e", n - 1, val);
+
+	/* find the exponent */
+	p = strchr(result, 'e');
+
+	/* punt if we have 'inf' or similar */
+	if (p == NULL)
+		return strlen(result);
+
+	exp = atoi(p + 1);
+	if (exp == 0)
+	{
+		/* just truncate off the 'e+00' */
+		*p = '\0';
+	}
+	else
+	{
+		if (Abs(exp) <= 4)
+		{
+			/*
+			 * remove the decimal point from the mantissa and write the digits
+			 * to the buf array
+			 */
+			for (p = result + sign, i = 10, dp = 0; *p != 'e'; p++, i++)
+			{
+				buf[i] = *p;
+				if (*p == '.')
+				{
+					dp = i--;	/* skip the decimal point */
+				}
+			}
+			if (dp == 0)
+				dp = i--;		/* no decimal point was found in the above
+								 * for() loop */
+
+			if (exp > 0)
+			{
+				if (dp - 10 + exp >= n)
+				{
+					/*
+					 * the decimal point is behind the last significant digit;
+					 * the digits in between must be converted to the exponent
+					 * and the decimal point placed after the first digit
+					 */
+					exp = dp - 10 + exp - n;
+					buf[10 + n] = '\0';
+
+					/* insert the decimal point */
+					if (n > 1)
+					{
+						dp = 11;
+						for (i = 23; i > dp; i--)
+							buf[i] = buf[i - 1];
+						buf[dp] = '.';
+					}
+
+					/*
+					 * adjust the exponent by the number of digits after the
+					 * decimal point
+					 */
+					if (n > 1)
+						sprintf(&buf[11 + n], "e%d", exp + n - 1);
+					else
+						sprintf(&buf[11], "e%d", exp + n - 1);
+
+					if (sign)
+					{
+						buf[9] = '-';
+						strcpy(result, &buf[9]);
+					}
+					else
+						strcpy(result, &buf[10]);
+				}
+				else
+				{				/* insert the decimal point */
+					dp += exp;
+					for (i = 23; i > dp; i--)
+						buf[i] = buf[i - 1];
+					buf[11 + n] = '\0';
+					buf[dp] = '.';
+					if (sign)
+					{
+						buf[9] = '-';
+						strcpy(result, &buf[9]);
+					}
+					else
+						strcpy(result, &buf[10]);
+				}
+			}
+			else
+			{					/* exp <= 0 */
+				dp += exp - 1;
+				buf[10 + n] = '\0';
+				buf[dp] = '.';
+				if (sign)
+				{
+					buf[dp - 2] = '-';
+					strcpy(result, &buf[dp - 2]);
+				}
+				else
+					strcpy(result, &buf[dp - 1]);
+			}
+		}
+
+		/* do nothing for Abs(exp) > 4; %e must be OK */
+		/* just get rid of zeroes after [eE]- and +zeroes after [Ee]. */
+
+		/* ... this is not done yet. */
+	}
+	return strlen(result);
+}
+
+
+/*
+** Miscellany
+*/
+
+/* find out the number of significant digits in a string representing
+ * a floating point number
+ */
+int
+significant_digits(const char *s)
+{
+	const char *p = s;
+	int			n,
+				c,
+				zeroes;
+
+	zeroes = 1;
+	/* skip leading zeroes and sign */
+	for (c = *p; (c == '0' || c == '+' || c == '-') && c != 0; c = *(++p));
+
+	/* skip decimal point and following zeroes */
+	for (c = *p; (c == '0' || c == '.') && c != 0; c = *(++p))
+	{
+		if (c != '.')
+			zeroes++;
+	}
+
+	/* count significant digits (n) */
+	for (c = *p, n = 0; c != 0; c = *(++p))
+	{
+		if (!((c >= '0' && c <= '9') || (c == '.')))
+			break;
+		if (c != '.')
+			n++;
+	}
+
+	if (!n)
+		return zeroes;
+
+	return n;
+}
diff --git a/contrib/seg/seg.control b/contrib/seg/seg.control
new file mode 100644
index 0000000..9ac3080
--- /dev/null
+++ b/contrib/seg/seg.control
@@ -0,0 +1,6 @@
+# seg extension
+comment = 'data type for representing line segments or floating-point intervals'
+default_version = '1.3'
+module_pathname = '$libdir/seg'
+relocatable = true
+trusted = true