Initial commit

1 files changed, 43 insertions, 0 deletions

diff --git a/pkg/xtools/ranges/rgwindow.x b/pkg/xtools/ranges/rgwindow.x
new file mode 100644
index 00000000..fe495362
--- /dev/null
+++ b/pkg/xtools/ranges/rgwindow.x
@@ -0,0 +1,43 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<pkg/rg.h>
+
+# RG_WINDOW -- Intersect a set of ordered and merged ranges with a window.
+
+pointer procedure rg_window (rg, rmin, rmax)
+
+pointer	rg				# Ranges
+int	rmin, rmax			# Window
+
+pointer	rgout				# Pointer to windowed ranges
+
+int	i, j
+
+begin
+	if (rg == NULL)
+	    call error (0, "Range descriptor undefined")
+
+	# Allocate the range points array.
+
+	call malloc (rgout, LEN_RG + 2 * max (1, RG_NRGS(rg)), TY_STRUCT)
+
+	# Set the windowed ranges.
+
+	j = 0
+	do i = 1, RG_NRGS(rg) {
+	    if ((rmin <= RG_X2(rg, i)) && (rmax >= RG_X1(rg, i))) {
+		j = j + 1
+		RG_X1(rgout, j) = max (rmin, RG_X1(rg, i))
+		RG_X2(rgout, j) = min (rmax, RG_X2(rg, i))
+	    }
+	}
+
+	call realloc (rgout, LEN_RG + 2 * max (1, j), TY_STRUCT)
+	RG_NRGS(rgout) = j
+	RG_NPTS(rgout) = 0
+	do i = 1, RG_NRGS(rgout)
+	    RG_NPTS(rgout) = RG_NPTS(rgout) +
+		abs (RG_X1(rgout, i) - RG_X2(rgout, i)) + 1
+
+	return (rgout)
+end