Initial commit

1 files changed, 61 insertions, 0 deletions

diff --git a/sys/imfort/imgs2s.x b/sys/imfort/imgs2s.x
new file mode 100644
index 00000000..48b421df
--- /dev/null
+++ b/sys/imfort/imgs2s.x
@@ -0,0 +1,61 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<imhdr.h>
+include	"imfort.h"
+
+# IMGS2S -- Get a section from 2 dimensional image of type short.
+# No automatic datatype conversion is performed.  It is illegal to reference
+# out of bounds.
+
+procedure imgs2s (im, buf, i1, i2, j1, j2, ier)
+
+pointer	im			# image descriptor
+short	buf[ARB]		# user data buffer
+int	i1, i2			# first, last columns
+int	j1, j2			# first, last lines
+int	ier
+
+long	offset
+int	nchars, npix, op, j
+int	bfread()
+
+begin
+	# Verify in bounds.
+	if (i1 < 1 || i2 > IM_LEN(im,1) || i1 > i2) {
+	    ier = IE_XOOB
+	    call im_seterrim (ier, im)
+	    return
+	} else if (j1 < 1 || j2 > IM_LEN(im,2) || j1 > j2) {
+	    ier = IE_YOOB
+	    call im_seterrim (ier, im)
+	    return
+	} else if (IM_PIXTYPE(im) != TY_SHORT) {
+	    ier = IE_NOTSHORT
+	    call im_seterrim (ier, im)
+	    return
+	}
+
+	npix = i2 - i1 + 1
+	nchars = npix * SZ_SHORT
+	op = 1
+
+	do j = j1, j2 {
+	    # Compute offset into pixel file.
+	    offset = IM_PIXOFF(im) +
+		((j-1) * IM_LINESIZE(im) + (i1-1)) * SZ_SHORT
+
+	    # Read one line of data.
+	    if (nchars != bfread (IM_PIXFP(im), buf[op], nchars, offset)) {
+		ier = IE_RDPIX
+		call im_seterrim (ier, im)
+		return
+	    }
+
+	    # Swap bytes if necessary.
+	    call imswap (im, buf[op], nchars)
+
+	    op = op + npix
+	}
+
+	ier = OK
+end