1 files changed, 71 insertions, 0 deletions
diff --git a/contrib/btree_gist/btree_float4.c b/contrib/btree_gist/btree_float4.c
index 3604c73313a..016b2d3d68f 100644
--- a/contrib/btree_gist/btree_float4.c
+++ b/contrib/btree_gist/btree_float4.c
@@ -23,6 +23,7 @@ PG_FUNCTION_INFO_V1(gbt_float4_consistent);
 PG_FUNCTION_INFO_V1(gbt_float4_distance);
 PG_FUNCTION_INFO_V1(gbt_float4_penalty);
 PG_FUNCTION_INFO_V1(gbt_float4_same);
+PG_FUNCTION_INFO_V1(gbt_float4_sortsupport);
 
 static bool
 gbt_float4gt(const void *a, const void *b, FmgrInfo *flinfo)
@@ -209,3 +210,73 @@ gbt_float4_same(PG_FUNCTION_ARGS)
 	*result = gbt_num_same((void *) b1, (void *) b2, &tinfo, fcinfo->flinfo);
 	PG_RETURN_POINTER(result);
 }
+
+
+static int
+gbt_float4_sort_build_cmp(Datum a, Datum b, SortSupport ssup)
+{
+	float4KEY  *ia = (float4KEY *) DatumGetPointer(a);
+	float4KEY  *ib = (float4KEY *) DatumGetPointer(b);
+
+	/* for leaf items we expect lower == upper */
+	Assert(ia->lower == ia->upper);
+	Assert(ib->lower == ib->upper);
+
+	if (ia->lower == ib->lower)
+		return 0;
+
+	return (ia->lower > ib->lower) ? 1 : -1;
+}
+
+static Datum
+gbt_float4_abbrev_convert(Datum original, SortSupport ssup)
+{
+	float4KEY  *b1 = (float4KEY *) DatumGetPointer(original);
+
+	return Float4GetDatum(b1->lower);
+}
+
+static int
+gbt_float4_cmp_abbrev(Datum z1, Datum z2, SortSupport ssup)
+{
+	float4		a = DatumGetFloat4(z1);
+	float4		b = DatumGetFloat4(z2);
+
+	if (a > b)
+		return 1;
+	else if (a < b)
+		return -1;
+	else
+		return 0;
+}
+
+/*
+ * We never consider aborting the abbreviation.
+ */
+static bool
+gbt_float4_abbrev_abort(int memtupcount, SortSupport ssup)
+{
+	return false;
+}
+
+/*
+ * Sort support routine for fast GiST index build by sorting.
+ */
+Datum
+gbt_float4_sortsupport(PG_FUNCTION_ARGS)
+{
+	SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
+
+	if (ssup->abbreviate)
+	{
+		ssup->comparator = gbt_float4_cmp_abbrev;
+		ssup->abbrev_converter = gbt_float4_abbrev_convert;
+		ssup->abbrev_abort = gbt_float4_abbrev_abort;
+		ssup->abbrev_full_comparator = gbt_float4_sort_build_cmp;
+	}
+	else
+	{
+		ssup->comparator = gbt_float4_sort_build_cmp;
+	}
+	PG_RETURN_VOID();
+}