1 files changed, 43 insertions, 0 deletions
diff --git a/pkg/xtools/ranges/rgorder.x b/pkg/xtools/ranges/rgorder.x
new file mode 100644
index 00000000..7864ecb2
--- /dev/null
+++ b/pkg/xtools/ranges/rgorder.x
@@ -0,0 +1,43 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include <pkg/rg.h>
+
+# RG_ORDER -- Make all ranges increasing and order by the starting point.
+
+procedure rg_order (rg)
+
+pointer	rg				# Ranges
+
+int	i, j, temp
+
+begin
+	# Error check the range pointer.
+
+	if (rg == NULL)
+	    call error (0, "Range descriptor undefined")
+
+	# Make all ranges increasing.
+
+	do i = 1, RG_NRGS(rg) {
+	    if (RG_X1(rg, i) > RG_X2(rg, i)) {
+		temp = RG_X1(rg, i)
+		RG_X1(rg, i) = RG_X2(rg, i)
+		RG_X2(rg, i) = temp
+	    }
+	}
+
+	# Sort the ranges in increasing order.
+
+	do i = 1, RG_NRGS(rg) - 1 {
+	    do j = i + 1, RG_NRGS(rg) {
+		if (RG_X1(rg, i) > RG_X1(rg, j)) {
+		    temp = RG_X1(rg, i)
+		    RG_X1(rg, i) = RG_X1(rg, j)
+		    RG_X1(rg, j) = temp
+		    temp = RG_X2(rg, i)
+		    RG_X2(rg, i) = RG_X2(rg, j)
+		    RG_X2(rg, j) = temp
+		}
+	    }
+	}
+end