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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <imhdr.h>
include "imfort.h"
# IMGS2R -- Get a section from an image of type short or real. Automatic
# datatype conversion from short to real is performed if necessary. It is
# illegal to reference out of bounds.
procedure imgs2r (im, buf, i1, i2, j1, j2, ier)
pointer im # image descriptor
real buf[ARB] # user data buffer
int i1, i2 # first, last column
int j1, j2 # line number
int ier
long offset
int nchars, npix, j, op
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 && IM_PIXTYPE(im) != TY_REAL) {
ier = IE_PIXTYPE
call im_seterrim (ier, im)
return
}
npix = i2 - i1 + 1
nchars = npix * IM_SZPIXEL(im)
op = 1
do j = j1, j2 {
# Compute offset into pixel file.
offset = IM_PIXOFF(im) + (j-1) * IM_LINESIZE(im) +
(i1-1) * IM_SZPIXEL(im)
# 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)
# Convert the datatype if necessary.
if (IM_PIXTYPE(im) == TY_SHORT)
call achtsr (buf[op], buf[op], npix)
op = op + npix
}
ier = OK
end
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