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# 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
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