fits_overview.c

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//
// From https://heasarc.gsfc.nasa.gov/docs/software/fitsio/cexamples.html:
//
// FITS Tools: Handy FITS Utilities that illustrate how to use CFITSIO
// -------------------------------------------------------------------
//
// These are working programs written in ANSI C that illustrate how one can
// easily read, write, and modify FITS files using the CFITSIO library. Most of
// these programs are very short, containing only a few 10s of lines of
// executable code or less, yet they perform quite useful operations on FITS
// files. Copy the programs to your local machine, then compile, and link them
// with the CFITSIO library. A short description of how to use each program can
// be displayed by executing the program without any command line arguments.
//
// You may freely modify, reuse, and redistribute these programs as you wish. It
// is often easier to use one of these programs as a template when writing a new
// program, rather than coding the new program completely from scratch.
//
 
/**
 * \file
 * \ingroup lalpulsar_bin_FITSTools
 */
 
#include "config.h"
 
#include <string.h>
#include <stdio.h>
 
#if defined(HAVE_LIBCFITSIO)
// disable -Wstrict-prototypes flag for this header file as this causes
// a build failure for cfitsio-3.440+
#pragma GCC diagnostic ignored "-Wstrict-prototypes"
#include <fitsio.h>
#pragma GCC diagnostic pop
#else
#error CFITSIO library is not available
#endif
 
int main( int argc, char *argv[] )
{
  fitsfile *fptr = 0;         /* FITS file pointer, defined in fitsio.h */
  char keyname[FLEN_KEYWORD], colname[FLEN_VALUE], coltype[FLEN_VALUE];
  int status = 0;   /* CFITSIO status value MUST be initialized to zero! */
  int single = 0, hdupos = 0, hdutype = 0, bitpix = 0, naxis = 0, ncols = 0, ii = 0;
  long naxes[10], nrows = 0;
 
  int printhelp = ( argc == 2 && ( strcmp( argv[1], "-h" ) == 0 || strcmp( argv[1], "--help" ) == 0 ) );
 
  if ( printhelp || argc != 2 ) {
    fprintf( stderr, "Usage:  %s filename[ext] \n", argv[0] );
    fprintf( stderr, "\n" );
    fprintf( stderr, "List the structure of a single extension, or, if ext is \n" );
    fprintf( stderr, "not given, list the structure of the entire FITS file.  \n" );
    fprintf( stderr, "\n" );
    fprintf( stderr, "Note that it may be necessary to enclose the input file\n" );
    fprintf( stderr, "name in single quote characters on the Unix command line.\n" );
    return ( 0 );
  }
 
#if defined(PAGER) && defined(HAVE_POPEN) && defined(HAVE_PCLOSE)
  FILE *fout = popen( PAGER, "w" );
  if ( fout == NULL ) {
    fprintf( stderr, "Could not execute '%s'\n", PAGER );
    return ( 1 );
  }
#else
  FILE *fout = stdout;
#endif
 
  if ( !fits_open_file( &fptr, argv[1], READONLY, &status ) ) {
    fits_get_hdu_num( fptr, &hdupos ); /* Get the current HDU position */
 
    /* List only a single structure if a specific extension was given */
    if ( strchr( argv[1], '[' ) || strchr( argv[1], '+' ) ) {
      single++;
    }
 
    for ( ; !status; hdupos++ ) { /* Main loop for each HDU */
      fits_get_hdu_type( fptr, &hdutype, &status ); /* Get the HDU type */
 
      fprintf( fout, "\nHDU #%d  ", hdupos );
      if ( hdutype == IMAGE_HDU ) { /* primary array or image HDU */
        fits_get_img_param( fptr, 10, &bitpix, &naxis, naxes, &status );
 
        fprintf( fout, "Array:  NAXIS = %d,  BITPIX = %d\n", naxis, bitpix );
        for ( ii = 0; ii < naxis; ii++ ) {
          fprintf( fout, "   NAXIS%d = %ld\n", ii + 1, naxes[ii] );
        }
      } else { /* a table HDU */
        fits_get_num_rows( fptr, &nrows, &status );
        fits_get_num_cols( fptr, &ncols, &status );
 
        if ( hdutype == ASCII_TBL ) {
          fprintf( fout, "ASCII Table:  " );
        } else {
          fprintf( fout, "Binary Table:  " );
        }
 
        fprintf( fout, "%d columns x %ld rows\n", ncols, nrows );
        fprintf( fout, " COL NAME             FORMAT\n" );
 
        for ( ii = 1; ii <= ncols; ii++ ) {
          fits_make_keyn( "TTYPE", ii, keyname, &status ); /* make keyword */
          fits_read_key( fptr, TSTRING, keyname, colname, NULL, &status );
          fits_make_keyn( "TFORM", ii, keyname, &status ); /* make keyword */
          fits_read_key( fptr, TSTRING, keyname, coltype, NULL, &status );
 
          fprintf( fout, " %3d %-16s %-16s\n", ii, colname, coltype );
        }
      }
 
      if ( single ) {
        break;  /* quit if only listing a single HDU */
      }
 
      fits_movrel_hdu( fptr, 1, NULL, &status ); /* try move to next ext */
    }
 
    if ( status == END_OF_FILE ) {
      status = 0;  /* Reset normal error */
    }
    fits_close_file( fptr, &status );
  }
 
#if defined(PAGER) && defined(HAVE_POPEN) && defined(HAVE_PCLOSE)
  pclose( fout );
#endif
 
  if ( status ) {
    fits_report_error( stderr, status ); /* print any error message */
  }
  return ( status );
}