/* Copyright (c) 1993 Association of Universities for Research
 * in Astronomy. All rights reserved. Produced under National
 * Aeronautics and Space Administration Contract No. NAS5-26555.
 */
/*       WRITEFITS
 *
 * PURPOSE:
 *       Write FITS format data file
 *
 * CALLING SEQUENCE:
 *       retval = writefits(h,image,filename)
 *
 * INPUTS:
 *       h          (* Header) header structure (must have correct image size,
 *                  FITS header lines -- use FILLHDR to update)
 *       image      (short int) image data
 *       filename   (* char) name of FITS file
 *
 * OUTPUTS:
 *       returns 0 if successful, -1 if fails
 *
 * MODIFICATION HISTORY
 *       Created by R. White, 31 July 1991
 *       Modified by R. White, 16 June 1992, to make fixed-length records
 *         under VMS.
 *
 *
 * This test disc was produced under U.S. Government grant NAG W-2166 and has
 * been prepared for data management review only.  No license, right, or
 * interest in any trademark, copyright, or use other than as stated herein is
 * granted hereby.  Further distribution is prohibited.  October 1991.
 *
 */

#include <stdio.h>
#include <string.h>

#include "qfile.h"
#include "header.h"

extern int
writefits(h,image,filename)
Header *h;
short image[];
char *filename;
{
int i, npix;
QFILE *ifile;
char blank[80];

    /*
     * Check to see whether file already exists
     * (Don't bother under VMS, just make a new version)
     */
#ifndef VMS
    if (access(filename,0) == 0) {
        fprintf(stderr, "Error: file %s already exists\n",filename);
        return(-1);
    }
#endif
    /*
     * open file: 2880 byte records, no carriage control
     */
    ifile = qcreat(filename, 2880, 0);
    /*
     * write header
     */
    for (i=0; i < h->nhlines; i++) qwrite(ifile, h->hlines[i], 80);
    /*
     * write some blank lines if number of header lines is not a
     * multiple of 36 (2880 bytes)
     */
    for (i = 0; i<80; i++) blank[i] = ' ';
    for (i = ((h->nhlines-1) % 36) + 1; i<36; i++) qwrite(ifile, blank, 80);
    /*
     * write data one byte at a time to ensure proper byte order
     */
    npix = h->section_x_length * h->section_y_length;
    for (i=0; i<npix; i++) {
        qputc( (image[i]>>8) & 0xff, ifile);
        qputc(  image[i]     & 0xff, ifile);
    }
    /*
     * write pad to bring data up to multiple of 2880 bytes too
     */
    for (i = ((2*npix-1) % 2880) + 1; i<2880; i++) qputc(0,ifile);
    qclose(ifile);
    return(0);
}