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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <fset.h>
include <mii.h>
include <mach.h>
# RFT_INIT_READ_PIXELS and READ_PIXELS -- Read pixel data with record buffering
# and data type conversion. The input data must meet the MII standard
# except for possibly in the case of integers having the least significant
# byte first.
#
# Read data in records of len_record and convert to the specified IRAF
# data type. Successive calls of rft_read_pixels returns the next npix pixels.
# Read_pixels returns EOF or the number of pixels converted.
# Init_read_pixels must be called before read_pixels.
#
# Error conditions are:
# 1. A short input record
# 2. Error in converting the pixels by miiup.
#
# This routine is based on the MII unpack routine which is machine dependent.
# The bitpix must correspond to an MII type. If the lsbf (least significant
# byte first) flag is YES then the pixels do not satisfy the MII standard.
# In this case the bytes are first swapped into most significant byte first
# before the MII unpack routine is called.
int procedure rft_init_read_pixels (npix_record, bitpix, lsbf, spp_type)
int npix_record # number of pixels per input record
int bitpix # bits per pixel (must correspond to an MII type)
int lsbf # byte swap?
int spp_type # SPP data type to be returned
# entry rft_read_pixels (fd, buffer, npix)
int rft_read_pixels
int fd # input file descriptor
char buffer[1] # output buffer
int npix # number of pixels to read
int swap
int ty_mii, ty_spp, npix_rec, nch_rec, sz_rec, nchars, len_mii, recptr
int bufsize, i, n, ip, op
pointer mii, spp
int rft_getbuf(), sizeof(), miilen()
errchk miilen, mfree, malloc, rft_getbuf, miiupk
data mii/NULL/, spp/NULL/
begin
ty_mii = bitpix
ty_spp = spp_type
swap = lsbf
npix_rec = npix_record
nch_rec = npix_rec * sizeof (ty_spp)
len_mii = miilen (npix_rec, ty_mii)
sz_rec = len_mii * SZ_INT
if (mii != NULL)
call mfree (mii, TY_INT)
call malloc (mii, len_mii, TY_INT)
if (spp != NULL)
call mfree (spp, TY_CHAR)
call malloc (spp, nch_rec, TY_CHAR)
ip = nch_rec
return (OK)
entry rft_read_pixels (fd, buffer, npix, recptr, bufsize)
nchars = npix * sizeof (ty_spp)
op = 0
repeat {
# If data is exhausted read the next record
if (ip == nch_rec) {
i = rft_getbuf (fd, Memi[mii], sz_rec, bufsize, recptr)
if (i == EOF)
return (EOF)
if (swap == YES)
switch (ty_mii) {
case MII_SHORT:
call bswap2 (Memi[mii], 1, Memi[mii], 1,
sz_rec * SZB_CHAR)
case MII_LONG:
call bswap4 (Memi[mii], 1, Memi[mii], 1,
sz_rec * SZB_CHAR)
}
call miiupk (Memi[mii], Memc[spp], npix_rec, ty_mii, ty_spp)
ip = 0
#recptr = recptr + 1
}
n = min (nch_rec - ip, nchars - op)
call amovc (Memc[spp+ip], buffer[1+op], n)
ip = ip + n
op = op + n
} until (op == nchars)
return (npix)
end
# RFT_GETBUF -- Procedure to get the buffer.
int procedure rft_getbuf (fd, buf, sz_rec, bufsize, recptr)
int fd # file descriptor
char buf[ARB] # buffer to be filled
int sz_rec # size in chars of record to be read
int bufsize # buffer size in records
int recptr # last successful FITS record read
int i, nchars
int read(), fstati()
errchk read
begin
nchars = 0
repeat {
iferr {
i = read (fd, buf[nchars+1], sz_rec - nchars)
} then {
call printf ("Error reading FITS record %d\n")
if (mod (recptr + 1, bufsize) == 0)
call pargi ((recptr + 1) / bufsize)
else
call pargi ((recptr + 1) / bufsize + 1)
call fseti (fd, F_VALIDATE, fstati (fd, F_SZBBLK) / SZB_CHAR)
i = read (fd, buf[nchars+1], sz_rec - nchars)
}
if (i == EOF)
break
else
nchars = nchars + i
} until (nchars >= sz_rec)
if ((i == EOF) && (nchars == 0))
return (EOF)
else {
recptr = recptr + 1
return (nchars)
}
end
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