From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Wed, 8 Jul 2015 20:46:52 -0400
Subject: Initial commit

---
 sys/imio/imggsc.x | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 sys/imio/imggsc.x

(limited to 'sys/imio/imggsc.x')

diff --git a/sys/imio/imggsc.x b/sys/imio/imggsc.x
new file mode 100644
index 00000000..caccc6a3
--- /dev/null
+++ b/sys/imio/imggsc.x
@@ -0,0 +1,105 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<syserr.h>
+include	<plset.h>
+include	<imhdr.h>
+include	<imio.h>
+
+# IMGGSC -- Get a general section, any datatype (called by one of the typed
+# procedures, which subsequently convert the datatype of the pixels returned
+# by this routine).  The mapping of the subraster in the input buffer to the
+# imagefile is described by the section descriptor vectors VS and VE.  Images
+# of up to IM_MAXDIM dimensions are permitted, and each dimension may be
+# accessed in either the forward or reverse direction.
+
+pointer procedure imggsc (im, vs, ve, ndim, dtype, totpix)
+
+pointer	im			# image descriptor
+long	vs[ARB], ve[ARB]	# logical coords of corners of section
+int	ndim			# dimensionality of section
+int	dtype			# datatype of pixels desired
+long	totpix			# total pixels in section (output)
+
+bool	rlio
+pointer	sp, px, bp, line, rl_high
+long	v[IM_MAXDIM], vinc[IM_MAXDIM]
+long	pvs[IM_MAXDIM], pve[IM_MAXDIM]
+int	sz_pixel, inbounds, npix, xstep, n
+
+pointer	imgibf()
+int	imsinb(), imloop(), pl_p2ri(), sizeof()
+errchk	imgibf, imrdpx, imrbpx
+include <szpixtype.inc>
+
+begin
+	#sz_pixel = sizeof(IM_PIXTYPE(im))
+	#sz_pixel = max ( sizeof(dtype), sizeof(IM_PIXTYPE(im)) )
+	#sz_pixel = pix_size[IM_PIXTYPE(im)]
+	sz_pixel = sizeof(IM_PIXTYPE(im))
+	rlio = (and (IM_PLFLAGS(im), PL_RLIO+PL_FAST) == PL_RLIO)
+
+	# Check that the section does not extend out of bounds.
+	inbounds = imsinb (im, vs, ve, ndim)
+	if (inbounds == ERR)
+	    call imerr (IM_NAME(im), SYS_IMREFOOB)
+
+	# Get an (input) buffer to put the pixels into.  Map the logical
+	# section into a physical section.  Prepare the section descriptor
+	# do-loop index and increment vectors V, VINC.
+
+	bp = imgibf (im, vs, ve, ndim, dtype)
+	call imaplv (im, vs, pvs, ndim)
+	call imaplv (im, ve, pve, ndim)
+	call imsslv (im, pvs, pve, v, vinc, npix)
+
+	# A temporary pixel buffer is required for RLIO conversions.
+	if (rlio) {
+	    call smark (sp)
+	    call salloc (px, npix, TY_INT)
+	}
+
+	line = bp
+	totpix = 0
+	rl_high = bp - 1
+
+	# Read the section into the input buffer, line segment by line segment,
+	# advancing through the dimensions in storage order (leftmost subscript
+	# varies fastest).
+
+	repeat {
+	    xstep = vinc[1]
+
+	    # Convert the pixel array to a range list? (image masks).  This is
+	    # done more efficiently at a lower level if no complex geometric
+	    # transformations are required (due to sections or OOB references).
+
+	    if (rlio) {
+		if (inbounds == YES)
+		    call imrdpx (im, Memi[px], npix, v, xstep) 
+		else
+		    call imrbpx (im, Memi[px], npix, v, xstep) 
+
+		if (rl_high >= line)
+		    call imerr (IM_NAME(im), SYS_IMRLOVFL)
+		else {
+		    n = pl_p2ri (Memi[px], 1, Memc[line], npix)
+		    rl_high = line + (n * RL_LENELEM * sz_pixel) - 1
+		}
+
+	    } else {
+		if (inbounds == YES)
+		    call imrdpx (im, Memc[line], npix, v, xstep) 
+		else
+		    call imrbpx (im, Memc[line], npix, v, xstep) 
+	    }
+
+	    line = line + (npix * sz_pixel)
+	    totpix = totpix + npix
+
+	} until (imloop (v, pvs, pve, vinc, IM_NPHYSDIM(im)) == LOOP_DONE)
+
+	if (rlio)
+	    call sfree (sp)
+
+	return ((bp - 1) / sizeof(dtype) + 1)
+end
-- 
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