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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
include <imhdr.h>
include <imio.h>
# IMGNLN -- Get the next line from an image of any dimension or datatype.
# This is a sequential operator. The index vector V should be initialized
# to the first line to be read before the first call. Each call increments
# the leftmost subscript by one, until V equals IM_LEN, at which time EOF
# is returned.
int procedure imgnln (im, lineptr, v, dtype)
pointer im
pointer lineptr # on output, points to the pixels
long v[IM_MAXDIM] # loop counter
int dtype # eventual datatype of pixels
int dim, ndim, junk, sz_pixel, fd, nchars, pixtype
long lineoff, line, band, offset
long vs[IM_MAXDIM], ve[IM_MAXDIM], unit_v[IM_MAXDIM], npix
int imloop()
pointer imggsc(), freadp()
errchk imggsc, imerr, imopsf
define retry_ 91
define oob_ 92
define misaligned_ 93
include <szpixtype.inc>
data unit_v /IM_MAXDIM * 1/
begin
ndim = IM_NDIM(im)
if (ndim == 0)
return (EOF)
npix = IM_LEN(im,1) # read entire line
pixtype = IM_PIXTYPE(im)
sz_pixel = pix_size[pixtype]
# Perform "zero trip" check (V >= VE), before entering "loop".
if (v[ndim] > IM_LEN(im,ndim))
return (EOF)
retry_
if (IM_FAST(im) == YES && pixtype == dtype && ndim <= 3) {
fd = IM_PFD(im)
if (fd == NULL) {
call imopsf (im)
goto retry_
}
# Lineoff is the dimensionless line offset in the pixel storage
# file (which we assume to be in line storage mode).
lineoff = 0
if (ndim > 1) {
line = v[2]
if (line < 1 || line > IM_LEN(im,2))
goto oob_
lineoff = line - 1
if (ndim > 2) {
band = v[3]
if (band < 1 || band > IM_LEN(im,3))
oob_ call imerr (IM_NAME(im), SYS_IMREFOOB)
lineoff = lineoff + (band - 1) * IM_PHYSLEN(im,2)
}
}
# Reference directly into the FIO buffer. If the image line
# straddles a FIO block boundary freadp calls error and we must
# use a separate buffer.
offset = lineoff * IM_PHYSLEN(im,1) * sz_pixel + IM_PIXOFF(im)
nchars = IM_PHYSLEN(im,1) * sz_pixel
iferr (lineptr = (freadp (fd, offset, nchars) - 1) / sz_pixel + 1)
goto misaligned_
} else {
misaligned_
# Prepare section descriptor vectors.
vs[1] = 1
ve[1] = npix
do dim = 2, ndim {
vs[dim] = v[dim]
ve[dim] = v[dim]
}
# Get the line.
lineptr = imggsc (im, vs, ve, ndim, dtype, junk)
}
# Increment loop vector (cannot use nested loops since the dimension
# of the image is variable). Note this loop vector references
# logical section coordinates.
if (ndim == 1)
v[1] = IM_LEN(im,1) + 1
else if (ndim == 2 && IM_FAST(im) == YES)
v[2] = v[2] + 1
else
junk = imloop (v, unit_v, IM_LEN(im,1), unit_v, ndim)
return (npix)
end
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