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1 files changed, 59 insertions, 0 deletions

diff --git a/sys/plio/placcess.x b/sys/plio/placcess.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<syserr.h>
+include <plset.h>
+include	<plio.h>
+
+# PL_ACCESS -- Return a pointer (type short) to the encoded line list data
+# for the indicated mask image line.  A valid pointer is always returned;
+# if the mask line is empty, the pointer will point to "empty line" linelist.
+
+pointer procedure pl_access (pl, v)
+
+pointer	pl			#I mask descriptor
+long	v[PL_MAXDIM]		#I coordinates of desired line
+
+int	pl_reference()
+
+begin
+	return (Ref (pl, pl_reference(pl,v)))
+end
+
+
+# PL_REFERENCE -- Return a reference (llbuf offset) to the indicated mask
+# image line.  A valid offset is always returned; if the mask line is empty,
+# the offset will be that of the "empty line" linelist.
+
+int procedure pl_reference (pl, v)
+
+pointer	pl			#I mask descriptor
+long	v[PL_MAXDIM]		#I coordinates of desired line
+
+int	index, i
+int	totlen, axlen
+define	oob_ 91
+
+begin
+	# Compute the index of the line in the line pointer array.
+	if (PL_NAXES(pl) == 2) {
+	    # Optimized for case naxes=2.
+	    index = v[2]
+	    if (index < 1 || index > PL_AXLEN(pl,2))
+		goto oob_
+	} else {
+	    # General case.
+	    index = 1
+	    totlen = 1
+	    do i = 2, PL_NAXES(pl) {
+		axlen = PL_AXLEN(pl,i)
+		if (v[i] < 1 || v[i] > axlen)
+		    goto oob_
+		index = index + totlen * (v[i] - 1)
+		totlen = totlen * axlen
+	    }
+	}
+
+	return (PL_LP(pl,index))
+oob_
+	call syserr (SYS_PLREFOOB)
+end