/******************************************************************************/
/*                      Peter Kirchgessner                                    */
/*                      e-mail: peter@kirchgessner.net                        */
/*                      WWW   : http://www.kirchgessner.net                   */
/******************************************************************************/
/*  #BEG-HDR                                                                  */
/*                                                                            */
/*  Package       : FITS reading/writing library                              */
/*  Modul-Name    : fitsrw.c                                                  */
/*  Description   : Support of reading/writing FITS-files                     */
/*  Function(s)   : fits_new_filestruct    - (local) initialize file structure*/
/*                  fits_new_hdulist       - (local) initialize hdulist struct*/
/*                  fits_delete_filestruct - (local) delete file structure    */
/*                  fits_delete_recordlist - (local) delete record list       */
/*                  fits_delete_hdulist    - (local) delete hdu list          */
/*                  fits_nan_32            - (local) check IEEE NaN values    */
/*                  fits_nan_64            - (local) check IEEE NaN values    */
/*                  fits_get_error         - get error message                */
/*                  fits_set_error         - (local) set error message        */
/*                  fits_drop_error        - (local) remove an error message  */
/*                  fits_open              - open a FITS file                 */
/*                  fits_close             - close a FITS file                */
/*                  fits_add_hdu           - add a HDU to a FITS file         */
/*                  fits_add_card          - add a card to the HDU            */
/*                  fits_print_header      - print a single FITS header       */
/*                  fits_read_header       - (local) read in FITS header      */
/*                  fits_write_header      - write a FITS header              */
/*                  fits_decode_header     - (local) decode a header          */
/*                  fits_eval_pixrange     - (local) evaluate range of pixels */
/*                  fits_decode_card       - decode a card                    */
/*                  fits_search_card       - search a card in a record list   */
/*                  fits_image_info        - get information about image      */
/*                  fits_seek_image        - position to an image             */
/*                  fits_read_pixel        - read pixel values from file      */
/*                  fits_to_pgmraw         - convert FITS-file to PGM-file    */
/*                  pgmraw_to_fits         - convert PGM-file to FITS-file    */
/*                                                                            */
/*  Author        : P. Kirchgessner                                           */
/*  Date of Gen.  : 12-Apr-97                                                 */
/*  Last modified : 25-Aug-06                                                 */
/*  Version       : 0.12                                                      */
/*  Compiler Opt. :                                                           */
/*  Changes       :                                                           */
/*  #MOD-0001, nn, 20-Dec-97, Initialize some variables                       */
/*  #MOD-0002, pk, 16-Aug-06, Fix problems with internationalization          */
/*                                                                            */
/*  #END-HDR                                                                  */
/******************************************************************************/
/*  References:                                                               */
/*  - NOST, Definition of the Flexible Image Transport System (FITS),         */
/*    September 29, 1995, Standard, NOST 100-1.1                              */
/*    (ftp://nssdc.gsfc.nasa.gov/pub/fits/fits_standard_ps.Z)                 */
/*  - The FITS IMAGE Extension. A Proposal. J.D. Ponz, R.W. Thompson,         */
/*    J.R. Munoz, Feb. 7, 1992                                                */
/*    (ftp://www.cv.nrao.edu/fits/documents/standards/image.ps.gz)            */
/*                                                                            */
/******************************************************************************/

#define                                    VERSION 0.12

/******************************************************************************/
/* FITS reading/writing library                                               */
/* Copyright (C) 1997 Peter Kirchgessner                                      */
/* (email: peter@kirchgessner.net, WWW: http://www.kirchgessner.net)          */
/* The library was developed for a FITS-plug-in to GIMP, the GNU Image        */
/* Manipulation Program. But it is completely independent to that (beside use */
/* of glib). If someone finds it useful for other purposes, try to keep it    */
/* independent from your application.                                         */
/******************************************************************************/
/*                                                                            */
/* This program is free software: you can redistribute it and/or modify       */
/* it under the terms of the GNU General Public License as published by       */
/* the Free Software Foundation; either version 3 of the License, or          */
/* (at your option) any later version.                                        */
/*                                                                            */
/* This program is distributed in the hope that it will be useful,            */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of             */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              */
/* GNU General Public License for more details.                               */
/*                                                                            */
/* You should have received a copy of the GNU General Public License          */
/* along with this program.  If not, see <https://www.gnu.org/licenses/>.      */
/******************************************************************************/

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <glib.h>
#include <glib/gstdio.h>

#include "fits-io.h"


/* Declaration of local functions */

static FitsFile       * fits_new_filestruct    (void);
static FitsHduList    * fits_new_hdulist       (void);
static void             fits_delete_filestruct (FitsFile       *ff);
static void             fits_delete_recordlist (FitsRecordList *rl);
static void             fits_delete_hdulist    (FitsHduList    *hl);
static gint             fits_nan_32            (guchar         *value);
static gint             fits_nan_64            (guchar         *value);
static void             fits_set_error         (const char     *errmsg);
static void             fits_drop_error        (void);
static FitsRecordList * fits_read_header       (FILE           *fp,
                                                gint           *nrec);
static FitsHduList    * fits_decode_header     (FitsRecordList *hdr,
                                                glong           hdr_offset,
                                                glong           dat_offset);
static gint             fits_eval_pixrange     (FILE           *fp,
                                                FitsHduList    *hdu);


/* Error handling like a FIFO */
#define FITS_MAX_ERROR      16
#define FITS_ERROR_LENGTH  256

static gint  fits_n_error = 0;
static gchar fits_error[FITS_MAX_ERROR][FITS_ERROR_LENGTH];

/* What byte ordering for IEEE-format we are running on ? */
static gint fits_ieee32_intel    = 0;
static gint fits_ieee32_motorola = 0;
static gint fits_ieee64_intel    = 0;
static gint fits_ieee64_motorola = 0;

/* Macros */
#define FITS_RETURN(msg, val) { fits_set_error (msg); return (val); }
#define FITS_VRETURN(msg)     { fits_set_error (msg); return; }

/* Get pixel values from memory. p must be an (guchar *) */
#define FITS_GETBITPIX16(p,val) val = ((p[0] << 8) | (p[1]))
#define FITS_GETBITPIX32(p,val) val = \
          ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3])

/* Get floating point values from memory. p must be an (guchar *). */
/* The floating point values must directly correspond */
/* to machine representation. Otherwise it does not work. */
#define FITS_GETBITPIXM32(p,val) \
 { if (fits_ieee32_intel) {guchar uc[4]; \
   uc[0] = p[3]; uc[1] = p[2]; uc[2] = p[1]; uc[3] = p[0]; \
   val = *(FitsBitpixM32 *)uc; } \
   else if (fits_ieee32_motorola) { val = *(FitsBitpixM32 *)p; } \
   else if (fits_ieee64_motorola) {FitsBitpixM64 m64; \
   guchar *uc= (guchar *)&m64; \
   uc[0]=p[0]; uc[1]=p[1]; uc[2]=p[2]; uc[3]=p[3]; uc[4]=uc[5]=uc[6]=uc[7]=0; \
   val = (FitsBitpixM32)m64; } \
   else if (fits_ieee64_intel) {FitsBitpixM64 i64; \
   guchar *uc= (guchar *)&i64; \
   uc[0]=uc[1]=uc[2]=uc[3]=0; uc[7]=p[0]; uc[6]=p[1]; uc[5]=p[2]; uc[4]=p[3]; \
   val = (FitsBitpixM32)i64;} }

#define FITS_GETBITPIXM64(p,val) \
 { if (fits_ieee64_intel) {guchar uc[8]; \
   uc[0] = p[7]; uc[1] = p[6]; uc[2] = p[5]; uc[3] = p[4]; \
   uc[4] = p[3]; uc[5] = p[2]; uc[6] = p[1]; uc[7] = p[0]; \
   val = *(FitsBitpixM64 *)uc; } else val = *(FitsBitpixM64 *)p; }

#define FITS_WRITE_BOOLCARD(fp,key,value) \
{ gchar card[81]; \
  g_snprintf (card, sizeof (card), \
              "%-8.8s= %20s%50s", key, value ? "T" : "F", " "); \
  fwrite (card, 1, 80, fp); }

#define FITS_WRITE_LONGCARD(fp,key,value) \
{ gchar card[81]; \
  g_snprintf (card, sizeof (card), \
              "%-8.8s= %20ld%50s", key, (long)value, " "); \
  fwrite (card, 1, 80, fp); }

#define FITS_WRITE_DOUBLECARD(fp,key,value) \
{ gchar card[81], dbl[21], *istr; \
  g_ascii_dtostr (dbl, sizeof(dbl), (gdouble)value); \
  istr = strstr (dbl, "e"); \
  if (istr) *istr = 'E'; \
  g_snprintf (card, sizeof (card), \
              "%-8.8s= %20.20s%50s", key, dbl, " "); \
  fwrite (card, 1, 80, fp); }

#define FITS_WRITE_STRINGCARD(fp,key,value) \
{ gchar card[81]; int k;\
  g_snprintf (card, sizeof (card), \
              "%-8.8s= \'%s", key, value); \
  for (k = strlen (card); k < 81; k++) card[k] = ' '; \
  k = strlen (key); if (k < 8) card[19] = '\''; else card[11+k] = '\''; \
  fwrite (card, 1, 80, fp); }

#define FITS_WRITE_CARD(fp,value) \
{ gchar card[81]; \
  g_snprintf (card, sizeof (card), \
              "%-80.80s", value); \
  fwrite (card, 1, 80, fp); }


/* Macro to convert a double value to a string using '.' as decimal point */
#define FDTOSTR(buf,val) g_ascii_dtostr (buf, sizeof(buf), (gdouble)(val))


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_scanfdouble - (local) scan a string for a double value   */
/*                                                                           */
/* Parameters:                                                               */
/* const char *buf  [I] : the string to scan                                 */
/* double *value    [O] : where to write the double value to                 */
/*                                                                           */
/* Scan a string for a double value represented in "C" locale.               */
/* On success 1 is returned. On failure 0 is returned.                       */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static gboolean
fits_scanfdouble (const gchar *buf,
                  gdouble     *value)
{
  gboolean  retval  = FALSE;
  gchar    *bufcopy = g_strdup (buf);

  /* We should use g_ascii_strtod. This also allows scanning of hexadecimal */
  /* values like 0x02. But we want the behaviour of sscanf ("0x02","%lf",...*/
  /* that gives 0.0 in this case. So check the string if we have a hex-value*/

  if (bufcopy)
    {
      gchar *bufptr = bufcopy;

      /* Remove leading white space */
      g_strchug (bufcopy);

      /* Skip leading sign character */
      if ((*bufptr == '-') || (*bufptr == '+'))
        bufptr++;

      /* Start of hex value ? Take this as 0.0 */
      if ((bufptr[0] == '0') && (g_ascii_toupper (bufptr[1]) == 'X'))
        {
          *value = 0.0;
          retval = TRUE;
        }
      else
        {
          if (*bufptr == '.') /* leading decimal point ? Skip it */
            bufptr++;

          if (g_ascii_isdigit (*bufptr)) /* Expect the complete string is decimal */
            {
              gchar   *endptr;
              gdouble  gvalue = g_ascii_strtod (bufcopy, &endptr);

              if (errno == 0)
                {
                  *value = gvalue;
                  retval = TRUE;
                }
            }
        }

      g_free (bufcopy);
    }

  return retval;
}

/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_new_filestruct - (local) initialize file structure       */
/*                                                                           */
/* Parameters:                                                               */
/* -none-                                                                    */
/*                                                                           */
/* Returns a pointer to an initialized fits file structure.                  */
/* On failure, a NULL-pointer is returned.                                   */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static FitsFile *
fits_new_filestruct (void)
{
  return g_new0 (FitsFile, 1);
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_new_hdulist    - (local) initialize hdulist structure    */
/*                                                                           */
/* Parameters:                                                               */
/* -none-                                                                    */
/*                                                                           */
/* Returns a pointer to an initialized hdulist structure.                    */
/* On failure, a NULL-pointer is returned.                                   */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static FitsHduList *
fits_new_hdulist (void)
{
  return g_new0 (FitsHduList, 1);
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_delete_filestruct - (local) delete file structure        */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff   [I] : pointer to fits file structure                      */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Frees all memory allocated by the file structure.                         */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static void
fits_delete_filestruct (FitsFile *ff)
{
  if (ff == NULL)
    return;

  fits_delete_hdulist (ff->hdu_list);
  ff->hdu_list = NULL;

  g_free (ff);
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_delete_recordlist - (local) delete record list           */
/*                                                                           */
/* Parameters:                                                               */
/* FitsRecordList *rl  [I] : record list to delete                         */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static void
fits_delete_recordlist (FitsRecordList *rl)
{
  while (rl != NULL)
    {
      FitsRecordList *next;

      next = rl->next_record;
      rl->next_record = NULL;
      g_free (rl);

      rl = next;
    }
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_delete_hdulist - (local) delete hdu list                 */
/*                                                                           */
/* Parameters:                                                               */
/* FitsHduList *hl  [I] : hdu list to delete                               */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static void
fits_delete_hdulist (FitsHduList *hl)
{
  while (hl != NULL)
    {
      FitsHduList *next;

      fits_delete_recordlist (hl->header_record_list);
      next = hl->next_hdu;
      hl->next_hdu = NULL;
      g_free (hl);

      hl = next;
    }
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_nan_32 - (local) check for IEEE NaN values (32 bit)      */
/*                                                                           */
/* Parameters:                                                               */
/* unsigned char *v     [I] : value to check                                 */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function returns 1 if the value is a NaN. Otherwise 0 is returned.    */
/* The byte sequence at v must start with the sign/eponent byte.             */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static int
fits_nan_32 (guchar *v)
{
  register gulong k;

  k = (v[0] << 24) | (v[1] << 16) | (v[2] << 8) | v[3];
  k &= 0x7fffffff;  /* Don't care about the sign bit */

  /* See NOST Definition of the Flexible Image Transport System (FITS), */
  /* Appendix F, IEEE special formats. */
  return (((k >= 0x7f7fffff) && (k <= 0x7fffffff)) ||
          ((k >= 0x00000001) && (k <= 0x00800000)));
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_nan_64 - (local) check for IEEE NaN values (64 bit)      */
/*                                                                           */
/* Parameters:                                                               */
/* unsigned char *v     [I] : value to check                                 */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function returns 1 if the value is a NaN. Otherwise 0 is returned.    */
/* The byte sequence at v must start with the sign/eponent byte.             */
/* (currently we ignore the low order 4 bytes of the mantissa. Therefore     */
/* this function is the same as for 32 bits).                                */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static int
fits_nan_64 (guchar *v)
{
  register gulong k;

  k = (v[0] << 24) | (v[1] << 16) | (v[2] << 8) | v[3];
  k &= 0x7fffffff;  /* Don't care about the sign bit */

  /* See NOST Definition of the Flexible Image Transport System (FITS), */
  /* Appendix F, IEEE special formats. */
  return (((k >= 0x7f7fffff) && (k <= 0x7fffffff)) ||
          ((k >= 0x00000001) && (k <= 0x00800000)));
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_get_error - get an error message                         */
/*                                                                           */
/* Parameters:                                                               */
/* -none-                                                                    */
/*                                                                           */
/* If an error message has been set, a pointer to the message is returned.   */
/* Otherwise a NULL pointer is returned.                                     */
/* An inquired error message is removed from the error FIFO.                 */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gchar *
fits_get_error (void)
{
  static gchar errmsg[FITS_ERROR_LENGTH];
  gint         k;

  if (fits_n_error <= 0)
    return NULL;

  strcpy (errmsg, fits_error[0]);

  for (k = 1; k < fits_n_error; k++)
    strcpy (fits_error[k-1], fits_error[k]);

  fits_n_error--;

  return errmsg;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_set_error - (local) set an error message                 */
/*                                                                           */
/* Parameters:                                                               */
/* char *errmsg   [I] : Error message to set                                 */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Places the error message in the FIFO. If the FIFO is full,                */
/* the message is discarded.                                                 */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static void
fits_set_error (const gchar *errmsg)
{
  if (fits_n_error < FITS_MAX_ERROR)
    g_strlcpy (fits_error[fits_n_error], errmsg, FITS_ERROR_LENGTH);
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_drop_error - (local) remove an error message             */
/*                                                                           */
/* Parameters:                                                               */
/* -none-                                                                    */
/*                                                                           */
/* Removes the last error message from the error message FIFO                */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static void
fits_drop_error (void)
{
  if (fits_n_error > 0)
    fits_n_error--;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_open - open a FITS file                                  */
/*                                                                           */
/* Parameters:                                                               */
/* char *filename   [I] : name of file to open                               */
/* char *openmode   [I] : mode to open the file ("r", "w")                   */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* On success, a FitsFile-pointer is returned. On failure, a NULL-          */
/* pointer is returned.                                                      */
/* The functions scans through the file loading each header and analyzing    */
/* them.                                                                     */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

FitsFile *
fits_open (const gchar *filename,
           const gchar *openmode)

{
  gint            reading, writing, n_rec, n_hdr;
  glong           fpos_header, fpos_data;
  FILE           *fp;
  FitsFile       *ff;
  FitsRecordList *hdrlist;
  FitsHduList    *hdulist      = NULL;
  FitsHduList    *last_hdulist = NULL;

  /* Check the IEEE-format we are running on */
  {
    gfloat   one32 = 1.0;
    gdouble  one64 = 1.0;
    guchar  *op32  = (guchar *) &one32;
    guchar  *op64  = (guchar *) &one64;

    if (sizeof (float) == 4)
      {
        fits_ieee32_intel = (op32[3] == 0x3f);
        fits_ieee32_motorola = (op32[0] == 0x3f);
      }

    if (sizeof (double) == 8)
      {
        fits_ieee64_intel = (op64[7] == 0x3f);
        fits_ieee64_motorola = (op64[0] == 0x3f);
      }
  }

  if ((filename == NULL) || (*filename == '\0') || (openmode == NULL))
    FITS_RETURN ("fits_open: Invalid parameters", NULL);

  reading = (strcmp (openmode, "r") == 0);
  writing = (strcmp (openmode, "w") == 0);
  if ((!reading) && (!writing))
    FITS_RETURN ("fits_open: Invalid openmode", NULL);

  fp = g_fopen (filename, reading ? "rb" : "wb");
  if (fp == NULL)
    FITS_RETURN ("fits_open: fopen() failed", NULL);

  ff = fits_new_filestruct ();
  if (ff == NULL)
    {
      fclose (fp);
      FITS_RETURN ("fits_open: No more memory", NULL);
    }

  ff->fp = fp;
  ff->openmode = *openmode;

  if (writing)
    return ff;

  for (n_hdr = 0; ; n_hdr++)   /* Read through all HDUs */
    {
      fpos_header = ftell (fp);    /* Save file position of header */
      hdrlist = fits_read_header (fp, &n_rec);

      if (hdrlist == NULL)
        {
          if (n_hdr > 0)        /* At least one header must be present. */
            fits_drop_error (); /* If we got a header already, drop the error */
          break;
        }
      fpos_data = ftell (fp);      /* Save file position of data */

      /* Decode the header */
      hdulist = fits_decode_header (hdrlist, fpos_header, fpos_data);
      if (hdulist == NULL)
        {
          fits_delete_recordlist (hdrlist);
          break;
        }
      ff->n_hdu++;
      ff->n_pic += hdulist->numpic;

      if (hdulist->used.blank_value)
        ff->blank_used = TRUE;

      if (hdulist->used.nan_value)
        ff->nan_used = TRUE;

      if (n_hdr == 0)
        ff->hdu_list = hdulist;
      else
        last_hdulist->next_hdu = hdulist;

      last_hdulist = hdulist;

      /* Evaluate the range of pixel data */
      fits_eval_pixrange (fp, hdulist);

      /* Reposition to start of next header */
      if (fseek (fp, hdulist->data_offset + hdulist->data_size, SEEK_SET) < 0)
        break;
    }

  return ff;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_close - close a FITS file                                */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff  [I] : FITS file pointer                                    */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

void
fits_close (FitsFile *ff)
{
  if (ff == NULL)
    FITS_VRETURN ("fits_close: Invalid parameter");

  fclose (ff->fp);

  fits_delete_filestruct (ff);
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_add_hdu - add a HDU to the file                          */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff  [I] : FITS file pointer                                    */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Adds a new HDU to the list kept in ff. A pointer to the new HDU is        */
/* returned. On failure, a NULL-pointer is returned.                         */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

FitsHduList *
fits_add_hdu (FitsFile *ff)
{
  FitsHduList *newhdu, *hdu;

  if (ff->openmode != 'w')
    FITS_RETURN ("fits_add_hdu: file not open for writing", NULL);

  newhdu = fits_new_hdulist ();
  if (newhdu == NULL)
    return NULL;

  if (ff->hdu_list == NULL)
    {
      ff->hdu_list = newhdu;
    }
  else
    {
      hdu = ff->hdu_list;
      while (hdu->next_hdu != NULL)
        hdu = hdu->next_hdu;
      hdu->next_hdu = newhdu;
    }

  return newhdu;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_add_card - add a card to the HDU                         */
/*                                                                           */
/* Parameters:                                                               */
/* FitsHduList *hdulist [I] : HDU listr                                    */
/* char *card             [I] : card to add                                  */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The card must follow the standards of FITS. The card must not use a       */
/* keyword that is written using *hdulist itself. On success 0 is returned.  */
/* On failure -1 is returned.                                                */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gint
fits_add_card (FitsHduList *hdulist,
               const gchar *card)
{
  gint k;

  if (hdulist->naddcards >= FITS_NADD_CARDS)
    return -1;

  k = strlen (card);
  if (k < FITS_CARD_SIZE)
    {
      memset (&(hdulist->addcards[hdulist->naddcards][k]), ' ',
              FITS_CARD_SIZE - k);
      memcpy (hdulist->addcards[(hdulist->naddcards)++], card, k);
    }
  else
    {
      memcpy (hdulist->addcards[(hdulist->naddcards)++], card, FITS_CARD_SIZE);
    }

  return 0;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_print_header - print the internal representation         */
/*                                 of a single header                        */
/* Parameters:                                                               */
/* FitsHduList *hdr  [I] : pointer to the header                           */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

void
fits_print_header (FitsHduList *hdr)
{
  gint  k;
  gchar buf[G_ASCII_DTOSTR_BUF_SIZE];

  if (hdr->used.simple)
    printf ("Content of SIMPLE-header:\n");
  else
    printf ("Content of XTENSION-header %s:\n", hdr->xtension);

  printf ("header_offset : %ld\n", hdr->header_offset);
  printf ("data_offset   : %ld\n", hdr->data_offset);
  printf ("data_size     : %ld\n", hdr->data_size);
  printf ("used data_size: %ld\n", hdr->udata_size);
  printf ("bytes p.pixel : %d\n", hdr->bpp);
  printf ("pixmin        : %s\n", FDTOSTR (buf, hdr->pixmin));
  printf ("pixmax        : %s\n", FDTOSTR (buf, hdr->pixmax));

  printf ("naxis         : %d\n", hdr->naxis);
  for (k = 1; k <= hdr->naxis; k++)
    printf ("naxis%-3d      : %d\n", k, hdr->naxisn[k-1]);

  printf ("bitpix        : %d\n", hdr->bitpix);

  if (hdr->used.blank)
    printf ("blank         : %ld\n", hdr->blank);
  else
    printf ("blank         : not used\n");

  if (hdr->used.datamin)
    printf ("datamin       : %s\n", FDTOSTR (buf, hdr->datamin));
  else
    printf ("datamin       : not used\n");

  if (hdr->used.datamax)
    printf ("datamax       : %s\n", FDTOSTR (buf, hdr->datamax));
  else
    printf ("datamax       : not used\n");

  if (hdr->used.gcount)
    printf ("gcount        : %ld\n", hdr->gcount);
  else
    printf ("gcount        : not used\n");

  if (hdr->used.pcount)
    printf ("pcount        : %ld\n", hdr->pcount);
  else
    printf ("pcount        : not used\n");

  if (hdr->used.bscale)
    printf ("bscale        : %s\n", FDTOSTR (buf, hdr->bscale));
  else
    printf ("bscale        : not used\n");

  if (hdr->used.bzero)
    printf ("bzero         : %s\n", FDTOSTR (buf, hdr->bzero));
  else
    printf ("bzero         : not used\n");
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_read_header - (local) read FITS header                   */
/*                                                                           */
/* Parameters:                                                               */
/* FILE *fp   [I] : file pointer                                             */
/* int  *nrec [O] : number of records read                                   */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Reads in all header records up to the record that keeps the END-card.     */
/* A pointer to the record list is returned on success.                      */
/* On failure, a NULL-pointer is returned.                                   */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static FitsRecordList *
fits_read_header (FILE *fp,
                  gint *nrec)
{
  gchar           record[FITS_RECORD_SIZE];
  FitsRecordList *start_list = NULL;
  FitsRecordList *cu_record  = NULL;
  FitsRecordList *new_record;
  FitsData       *fdat;
  gint            k, simple, xtension;

  *nrec = 0;

  k = fread (record, 1, FITS_RECORD_SIZE, fp);
  if (k != FITS_RECORD_SIZE)
    FITS_RETURN ("fits_read_header: Error in read of first record", NULL);

  simple = (strncmp (record, "SIMPLE  ", 8) == 0);
  xtension = (strncmp (record, "XTENSION", 8) == 0);
  if ((!simple) && (!xtension))
    FITS_RETURN ("fits_read_header: Missing keyword SIMPLE or XTENSION", NULL);

  if (simple)
    {
      fdat = fits_decode_card (record, FITS_DATA_TYPE_FBOOL);
      if (fdat && !fdat->fbool)
        fits_set_error ("fits_read_header (warning): keyword SIMPLE does not "
                        "have value T");
    }

  for (;;)   /* Process all header records */
    {
      new_record = g_new0 (FitsRecordList, 1);
      memcpy (new_record->data, record, FITS_RECORD_SIZE);
      new_record->next_record = NULL;
      (*nrec)++;

      if (start_list == NULL)      /* Add new record to the list */
        start_list = new_record;
      else
        cu_record->next_record = new_record;

      cu_record = new_record;

      /* Was this the last record ? */
      if (fits_search_card (cu_record, "END") != NULL)
        break;

      k = fread (record, 1, FITS_RECORD_SIZE, fp);
      if (k != FITS_RECORD_SIZE)
        FITS_RETURN ("fits_read_header: Error in read of record", NULL);
    }

  return start_list;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_write_header - write a FITS header                       */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff [I] : FITS-file pointer                                     */
/* FitsHduList [I] : pointer to header                                     */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Writes a header to the file. On success, 0 is returned. On failure,       */
/* -1 is returned.                                                           */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gint
fits_write_header (FitsFile    *ff,
                   FitsHduList *hdulist)
{
  gint numcards;
  gint k;

  if (ff->openmode != 'w')
    FITS_RETURN ("fits_write_header: file not open for writing", -1);

  numcards = 0;

  if (hdulist->used.simple)
    {
      FITS_WRITE_BOOLCARD (ff->fp, "SIMPLE", 1);
      numcards++;
    }
  else if (hdulist->used.xtension)
    {
      FITS_WRITE_STRINGCARD (ff->fp, "XTENSION", hdulist->xtension);
      numcards++;
    }

  FITS_WRITE_LONGCARD (ff->fp, "BITPIX", hdulist->bitpix);
  numcards++;

  FITS_WRITE_LONGCARD (ff->fp, "NAXIS", hdulist->naxis);
  numcards++;

  for (k = 0; k < hdulist->naxis; k++)
    {
      gchar naxisn[16];

      g_snprintf (naxisn, sizeof (naxisn), "NAXIS%d", k+1);
      FITS_WRITE_LONGCARD (ff->fp, naxisn, hdulist->naxisn[k]);
      numcards++;
    }

  if (hdulist->used.extend)
    {
      FITS_WRITE_BOOLCARD (ff->fp, "EXTEND", hdulist->extend);
      numcards++;
    }

  if (hdulist->used.groups)
    {
      FITS_WRITE_BOOLCARD (ff->fp, "GROUPS", hdulist->groups);
      numcards++;
    }

  if (hdulist->used.pcount)
    {
      FITS_WRITE_LONGCARD (ff->fp, "PCOUNT", hdulist->pcount);
      numcards++;
    }

  if (hdulist->used.gcount)
    {
      FITS_WRITE_LONGCARD (ff->fp, "GCOUNT", hdulist->gcount);
      numcards++;
    }

  if (hdulist->used.bzero)
    {
      FITS_WRITE_DOUBLECARD (ff->fp, "BZERO", hdulist->bzero);
      numcards++;
    }

  if (hdulist->used.bscale)
    {
      FITS_WRITE_DOUBLECARD (ff->fp, "BSCALE", hdulist->bscale);
      numcards++;
    }

  if (hdulist->used.datamin)
    {
      FITS_WRITE_DOUBLECARD (ff->fp, "DATAMIN", hdulist->datamin);
      numcards++;
    }

  if (hdulist->used.datamax)
    {
      FITS_WRITE_DOUBLECARD (ff->fp, "DATAMAX", hdulist->datamax);
      numcards++;
    }

  if (hdulist->used.blank)
    {
      FITS_WRITE_LONGCARD (ff->fp, "BLANK", hdulist->blank);
      numcards++;
    }

  /* Write additional cards */
  if (hdulist->naddcards > 0)
    {
      fwrite (hdulist->addcards, FITS_CARD_SIZE, hdulist->naddcards, ff->fp);
      numcards += hdulist->naddcards;
    }

  FITS_WRITE_CARD (ff->fp, "END");
  numcards++;

  k = (numcards * FITS_CARD_SIZE) % FITS_RECORD_SIZE;
  if (k)  /* Must the record be filled up ? */
    {
      while (k++ < FITS_RECORD_SIZE)
        putc (' ', ff->fp);
    }

  return ferror (ff->fp) ? -1 : 0;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_decode_header - (local) decode a header                  */
/*                                                                           */
/* Parameters:                                                               */
/* FitsRecordList *hdr  [I] : the header record list                       */
/* long hdr_offset        [I] : fileposition of header                       */
/* long dat_offset        [I] : fileposition of data (end of header)         */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function decodes the mostly used data within the header and generates */
/* a FitsHduList-entry. On failure, a NULL-pointer is returned.            */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static FitsHduList *
fits_decode_header (FitsRecordList *hdr,
                    glong           hdr_offset,
                    glong           dat_offset)
{
  FitsHduList *hdulist;
  FitsData    *fdat;
  gchar        errmsg[80], key[9];
  gint         k, bpp, random_groups;
  glong        mul_axis, data_size, bitpix_supported;

#define FITS_DECODE_CARD(mhdr,mkey,mfdat,mtyp) \
  { strcpy (key, mkey);                                            \
    mfdat = fits_decode_card (fits_search_card (mhdr, mkey), mtyp);     \
    if (mfdat == NULL) goto err_missing; }

#define FITS_TRY_CARD(mhdr,mhdu,mkey,mvar,mtyp,unionvar) \
  { FitsData *mfdat = fits_decode_card (fits_search_card (mhdr,mkey), mtyp); \
    mhdu->used.mvar = (mfdat != NULL);                                  \
    if (mhdu->used.mvar) mhdu->mvar = mfdat->unionvar; }

  hdulist = fits_new_hdulist ();
  if (hdulist == NULL)
    FITS_RETURN ("fits_decode_header: Not enough memory", NULL);

  /* Initialize the header data */
  hdulist->header_offset = hdr_offset;
  hdulist->data_offset   = dat_offset;

  hdulist->used.simple   = (strncmp (hdr->data, "SIMPLE  ", 8) == 0);
  hdulist->used.xtension = (strncmp (hdr->data, "XTENSION", 8) == 0);

  if (hdulist->used.xtension)
    {
      fdat = fits_decode_card (fits_search_card (hdr, "XTENSION"),
                               FITS_DATA_TYPE_FSTRING);
      if (fdat != NULL)
        {
          strcpy (hdulist->xtension, fdat->fstring);
        }
      else
        {
          strcpy (errmsg, "No valid XTENSION header found.");
          goto err_return;
        }
    }

  FITS_DECODE_CARD (hdr, "NAXIS", fdat, FITS_DATA_TYPE_FLONG);
  hdulist->naxis = fdat->flong;

  FITS_DECODE_CARD (hdr, "BITPIX", fdat, FITS_DATA_TYPE_FLONG);
  bpp = hdulist->bitpix = (gint) fdat->flong;
  if ((bpp != 8)   && (bpp != 16) && (bpp != 32) &&
      (bpp != -32) && (bpp != -64))
    {
      strcpy (errmsg, "fits_decode_header: Invalid BITPIX-value");
      goto err_return;
    }

  if (bpp < 0)
    bpp = -bpp;

  bpp /= 8;
  hdulist->bpp = bpp;

  FITS_TRY_CARD (hdr, hdulist, "GCOUNT", gcount, FITS_DATA_TYPE_FLONG, flong);
  FITS_TRY_CARD (hdr, hdulist, "PCOUNT", pcount, FITS_DATA_TYPE_FLONG, flong);

  FITS_TRY_CARD (hdr, hdulist, "GROUPS", groups, FITS_DATA_TYPE_FLONG, fbool);
  random_groups = hdulist->used.groups && hdulist->groups;

  FITS_TRY_CARD (hdr, hdulist, "EXTEND", extend, FITS_DATA_TYPE_FBOOL, fbool);

  if (hdulist->used.xtension)  /* Extension requires GCOUNT and PCOUNT */
    {
      if (! hdulist->used.gcount || ! hdulist->used.pcount)
        {
          strcpy (errmsg, "fits_decode_header: Missing GCOUNT/PCOUNT for XTENSION");
          goto err_return;
        }
    }

  mul_axis = 1;

  /* Find all NAXISx-cards */
  for (k = 1; k <= FITS_MAX_AXIS; k++)
    {
      gchar naxisn[16];

      g_snprintf (naxisn, sizeof (naxisn), "NAXIS%-3d", k);
      fdat = fits_decode_card (fits_search_card (hdr, naxisn),
                               FITS_DATA_TYPE_FLONG);
      if (fdat == NULL)
        {
          k--;   /* Save the last NAXISk read */
          break;
        }

      hdulist->naxisn[k-1] = (int)fdat->flong;

      if (hdulist->naxisn[k-1] < 0)
        {
          strcpy (errmsg, "fits_decode_header: Negative value in NAXISn");
          goto err_return;
        }

      if ((k == 1) && random_groups)
        {
          if (hdulist->naxisn[0] != 0)
            {
              strcpy (errmsg, "fits_decode_header: Random groups with NAXIS1 != 0");
              goto err_return;
            }
        }
      else
        {
          mul_axis *= hdulist->naxisn[k - 1];
        }
    }

  if ((hdulist->naxis > 0) && (k < hdulist->naxis))
    {
      strcpy (errmsg, "fits_decode_card: Not enough NAXISn-cards");
      goto err_return;
    }

  /* If we have only one dimension, just set the second to size one. */
  /* So we don't have to check for naxis < 2 in some places. */
  if (hdulist->naxis < 2)
    hdulist->naxisn[1] = 1;

  if (hdulist->naxis < 1)
    {
      mul_axis = 0;
      hdulist->naxisn[0] = 1;
    }

  if (hdulist->used.xtension)
    data_size = bpp * hdulist->gcount * (hdulist->pcount + mul_axis);
  else
    data_size = bpp * mul_axis;

  hdulist->udata_size = data_size;  /* Used data size without padding */

  /* Datasize must be a multiple of the FITS logical record size */
  data_size = (data_size + FITS_RECORD_SIZE - 1) / FITS_RECORD_SIZE;
  data_size *= FITS_RECORD_SIZE;
  hdulist->data_size = data_size;

  FITS_TRY_CARD (hdr, hdulist, "BLANK", blank, FITS_DATA_TYPE_FLONG, flong);

  FITS_TRY_CARD (hdr, hdulist, "DATAMIN", datamin, FITS_DATA_TYPE_FDOUBLE, fdouble);
  FITS_TRY_CARD (hdr, hdulist, "DATAMAX", datamax, FITS_DATA_TYPE_FDOUBLE, fdouble);

  FITS_TRY_CARD (hdr, hdulist, "BZERO", bzero, FITS_DATA_TYPE_FDOUBLE, fdouble);
  FITS_TRY_CARD (hdr, hdulist, "BSCALE", bscale, FITS_DATA_TYPE_FDOUBLE, fdouble);

  /* Evaluate number of interpretable images for this HDU */
  hdulist->numpic = 0;

  /* We must support this format */
  bitpix_supported =    (hdulist->bitpix > 0)
                     || (   (hdulist->bitpix == -64)
                         && (fits_ieee64_intel || fits_ieee64_motorola))
                     || (   (hdulist->bitpix == -32)
                         && (   fits_ieee32_intel || fits_ieee32_motorola
                             || fits_ieee64_intel || fits_ieee64_motorola));

  if (bitpix_supported)
    {
      if (hdulist->used.simple)
        {
          if (hdulist->naxis > 0)
            {
              hdulist->numpic = 1;
              for (k = 3; k <= hdulist->naxis; k++)
                hdulist->numpic *= hdulist->naxisn[k - 1];
            }
        }
      else if (hdulist->used.xtension &&
               (strncmp (hdulist->xtension, "IMAGE", 5) == 0))
        {
          if (hdulist->naxis > 0)
            {
              hdulist->numpic = 1;
              for (k = 3; k <= hdulist->naxis; k++)
                hdulist->numpic *= hdulist->naxisn[k - 1];
            }
        }
    }
  else
    {
      gchar msg[160];

      g_snprintf (msg, sizeof (msg),
                  "fits_decode_header: IEEE floating point format required for "
                  "BITPIX=%d\nis not supported on this machine",
                  hdulist->bitpix);
      fits_set_error (msg);
    }

  hdulist->header_record_list = hdr;  /* Add header records to the list */

  return hdulist;

 err_missing:
  g_snprintf (errmsg, sizeof (errmsg),
              "fits_decode_header: missing/invalid %s card", key);

 err_return:
  fits_delete_hdulist (hdulist);
  fits_set_error (errmsg);

  return NULL;

#undef FITS_DECODE_CARD
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_eval_pixrange - (local) evaluate range of pixel data     */
/*                                                                           */
/* Parameters:                                                               */
/* FILE *fp               [I] : file pointer                                 */
/* FitsHduList *hdu     [I] : pointer to header                            */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The Function sets the values hdu->pixmin and hdu->pixmax. On success 0    */
/* is returned. On failure, -1 is returned.                                  */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

static gint
fits_eval_pixrange (FILE        *fp,
                    FitsHduList *hdu)
{
  register gint maxelem;
#define FITSNPIX 4096
  guchar        pixdat[FITSNPIX];
  gint          nelem, bpp;
  gboolean      blank_found = FALSE;
  gboolean      nan_found   = FALSE;

  if (fseek (fp, hdu->data_offset, SEEK_SET) < 0)
    FITS_RETURN ("fits_eval_pixrange: can't position file", -1);

  bpp   = hdu->bpp;                /* Number of bytes per pixel */
  nelem = hdu->udata_size / bpp;   /* Number of data elements */

  switch (hdu->bitpix)
    {
    case 8:
      {
        register FitsBitpix8  pixval;
        register guchar      *ptr;
        FitsBitpix8           minval = 255;
        FitsBitpix8           maxval = 0;

        while (nelem > 0)
          {
            maxelem = sizeof (pixdat) / bpp;
            if (nelem < maxelem)
              maxelem = nelem;

            nelem -= maxelem;
            if (fread ((gchar *) pixdat, bpp, maxelem, fp) != maxelem)
              FITS_RETURN ("fits_eval_pixrange: error on read bitpix 8 data", -1);

            ptr = pixdat;
            if (hdu->used.blank)
              {
                FitsBitpix8 blankval = (FitsBitpix8) hdu->blank;

                while (maxelem-- > 0)
                  {
                    pixval = (FitsBitpix8)*(ptr++);

                    if (pixval != blankval)
                      {
                        if (pixval < minval)
                          minval = pixval;
                        else if (pixval > maxval)
                          maxval = pixval;
                      }
                    else
                      {
                        blank_found = TRUE;
                      }
                  }
              }
            else
              {
                while (maxelem-- > 0)
                  {
                    pixval = (FitsBitpix8)*(ptr++);

                    if (pixval < minval)
                      minval = pixval;
                    else if (pixval > maxval)
                      maxval = pixval;
                  }
              }
          }

        hdu->pixmin = minval;
        hdu->pixmax = maxval;
        break;
      }

    case 16:
      {
        register FitsBitpix16  pixval;
        register guchar       *ptr;
        FitsBitpix16           minval = 0x7fff;
        FitsBitpix16           maxval = ~0x7fff;

        while (nelem > 0)
          {
            maxelem = sizeof (pixdat) / bpp;
            if (nelem < maxelem)
              maxelem = nelem;

            nelem -= maxelem;
            if (fread ((gchar *) pixdat, bpp, maxelem, fp) != maxelem)
              FITS_RETURN ("fits_eval_pixrange: error on read bitpix 16 data", -1);

            ptr = pixdat;
            if (hdu->used.blank)
              {
                FitsBitpix16 blankval = (FitsBitpix16) hdu->blank;

                while (maxelem-- > 0)
                  {
                    FITS_GETBITPIX16 (ptr, pixval);
                    ptr += 2;

                    if (pixval != blankval)
                      {
                        if (pixval < minval)
                          minval = pixval;
                        else if (pixval > maxval)
                          maxval = pixval;
                      }
                    else
                      {
                        blank_found = TRUE;
                      }
                  }
              }
            else
              {
                while (maxelem-- > 0)
                  {
                    FITS_GETBITPIX16 (ptr, pixval);
                    ptr += 2;

                    if (pixval < minval)
                      minval = pixval;
                    else if (pixval > maxval)
                      maxval = pixval;
                  }
              }
          }

        hdu->pixmin = minval;
        hdu->pixmax = maxval;
        break;
      }

    case 32:
      {
        register FitsBitpix32  pixval;
        register guchar       *ptr;
        FitsBitpix32           minval = 0x7fffffff;
        FitsBitpix32           maxval = ~0x7fffffff;

        while (nelem > 0)
          {
            maxelem = sizeof (pixdat)/bpp;
            if (nelem < maxelem)
              maxelem = nelem;

            nelem -= maxelem;
            if (fread ((gchar *) pixdat, bpp, maxelem, fp) != maxelem)
              FITS_RETURN ("fits_eval_pixrange: error on read bitpix 32 data", -1);

            ptr = pixdat;
            if (hdu->used.blank)
              {
                FitsBitpix32 blankval = (FitsBitpix32)hdu->blank;

                while (maxelem-- > 0)
                  {
                    FITS_GETBITPIX32 (ptr, pixval);
                    ptr += 4;

                    if (pixval != blankval)
                      {
                        if (pixval < minval)
                          minval = pixval;
                        else if (pixval > maxval)
                          maxval = pixval;
                      }
                    else
                      {
                        blank_found = TRUE;
                      }
                  }
              }
            else
              {
                while (maxelem-- > 0)
                  {
                    FITS_GETBITPIX32 (ptr, pixval);
                    ptr += 4;

                    if (pixval < minval)
                      minval = pixval;
                    else if (pixval > maxval)
                      maxval = pixval;
                  }
              }
          }

        hdu->pixmin = minval;
        hdu->pixmax = maxval;
        break;
      }

    case -32:
      {
        register FitsBitpixM32  pixval = 0;
        register guchar        *ptr;
        FitsBitpixM32           minval = 0;
        FitsBitpixM32           maxval = 0;
        gboolean                first  = TRUE;

        while (nelem > 0)
          {
            maxelem = sizeof (pixdat) / bpp;
            if (nelem < maxelem)
              maxelem = nelem;

            nelem -= maxelem;
            if (fread ((gchar *) pixdat, bpp, maxelem, fp) != maxelem)
              FITS_RETURN ("fits_eval_pixrange: error on read bitpix -32 data", -1);

            ptr = pixdat;
            while (maxelem-- > 0)
              {
                if (! fits_nan_32 (ptr))
                  {
                    FITS_GETBITPIXM32 (ptr, pixval);
                    ptr += 4;

                    if (first)
                      {
                        first = FALSE;
                        minval = maxval = pixval;
                      }
                    else if (pixval < minval)
                      {
                        minval = pixval;
                      }
                    else if (pixval > maxval)
                      {
                        maxval = pixval;
                      }
                  }
                else
                  {
                    nan_found = TRUE;
                  }
              }
          }

        hdu->pixmin = minval;
        hdu->pixmax = maxval;
        break;
      }

    case -64:
      {
        register FitsBitpixM64  pixval;
        register guchar        *ptr;
        FitsBitpixM64           minval = 0;
        FitsBitpixM64           maxval = 0;
        gboolean                first  = TRUE;

        while (nelem > 0)
          {
            maxelem = sizeof (pixdat) / bpp;
            if (nelem < maxelem)
              maxelem = nelem;

            nelem -= maxelem;
            if (fread ((gchar *) pixdat, bpp, maxelem, fp) != maxelem)
              FITS_RETURN ("fits_eval_pixrange: error on read bitpix -64 data", -1);

            ptr = pixdat;
            while (maxelem-- > 0)
              {
                if (! fits_nan_64 (ptr))
                  {
                    FITS_GETBITPIXM64 (ptr, pixval);
                    ptr += 8;

                    if (first)
                      {
                        first = FALSE;
                        minval = maxval = pixval;
                      }
                    else if (pixval < minval)
                      {
                        minval = pixval;
                      }
                    else if (pixval > maxval)
                      {
                        maxval = pixval;
                      }
                  }
                else
                  {
                    nan_found = TRUE;
                  }
              }
          }

        hdu->pixmin = minval;
        hdu->pixmax = maxval;
        break;
      }
    }

  if (nan_found)
    hdu->used.nan_value = TRUE;

  if (blank_found)
    hdu->used.blank_value = TRUE;

  return 0;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_decode_card - decode a card                              */
/*                                                                           */
/* Parameters:                                                               */
/* const char *card   [I] : pointer to card image                            */
/* FitsDataType data_type [I] : datatype to decode                           */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* Decodes a card and returns a pointer to the union, keeping the data.      */
/* If card is NULL or on failure, a NULL-pointer is returned.                */
/* If the card does not have the value indicator, an error is generated,     */
/* but its tried to decode the card. The data is only valid up to the next   */
/* call of the function.                                                     */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

FitsData *
fits_decode_card (const gchar  *card,
                  FitsDataType  data_type)
{
  static FitsData  data;
  glong            l_long;
  gdouble          l_double;
  gchar            l_card[FITS_CARD_SIZE + 1];
  gchar            msg[256];
  gchar           *cp, *dst, *end;
  gint             ErrCount = 0;

  if (card == NULL)
    return NULL;

  memcpy (l_card, card, FITS_CARD_SIZE);
  l_card[FITS_CARD_SIZE] = '\0';

  if (strncmp (card+8, "= ", 2) != 0)
    {
      g_snprintf (msg, sizeof (msg),
                  "fits_decode_card (warning): Missing value indicator "
                  "'= ' for %8.8s", l_card);
      fits_set_error (msg);
      ErrCount++;
    }

  switch (data_type)
    {
    case FITS_DATA_TYPE_BITPIX_8:
      data.bitpix8 = (FitsBitpix8) (l_card[10]);
      break;

    case FITS_DATA_TYPE_BITPIX_16:
      if (sscanf (l_card + 10, "%ld", &l_long) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_BITPIX_16");
          ErrCount++;
          break;
        }
      data.bitpix16 = (FitsBitpix16) l_long;
      break;

    case FITS_DATA_TYPE_BITPIX_32:
      if (sscanf (l_card + 10, "%ld", &l_long) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_BITPIX_32");
          ErrCount++;
          break;
        }
      data.bitpix32 = (FitsBitpix32) l_long;
      break;

    case FITS_DATA_TYPE_BITPIX_M32:
      if (fits_scanfdouble (l_card + 10, &l_double) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_BITPIX_M32");
          ErrCount++;
          break;
        }
      data.bitpixm32 = (FitsBitpixM32) l_double;
      break;

    case FITS_DATA_TYPE_BITPIX_M64:
      if (fits_scanfdouble (l_card + 10, &l_double) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_BITPIX_M64");
          ErrCount++;
          break;
        }
      data.bitpixm64 = (FitsBitpixM64) l_double;
      break;

    case FITS_DATA_TYPE_FBOOL:
      cp = l_card + 10;
      while (*cp == ' ')
        cp++;

      if (*cp == 'T')
        {
          data.fbool = 1;
        }
      else if (*cp == 'F')
        {
          data.fbool = 0;
        }
      else
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_FBOOL");
          ErrCount++;
          break;
        }
      break;

    case FITS_DATA_TYPE_FLONG:
      if (sscanf (l_card + 10, "%ld", &l_long) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_FLONG");
          ErrCount++;
          break;
        }
      data.flong = (FitsBitpix32) l_long;
      break;

    case FITS_DATA_TYPE_FDOUBLE:
      if (fits_scanfdouble (l_card + 10, &l_double) != 1)
        {
          fits_set_error ("fits_decode_card: error decoding FITS_DATA_TYPE_FDOUBLE");
          ErrCount++;
          break;
        }
      data.fdouble = (FitsBitpixM32) l_double;
      break;

    case FITS_DATA_TYPE_FSTRING:
      cp = l_card + 10;
      if (*cp != '\'')
        {
          fits_set_error ("fits_decode_card: missing \' decoding FITS_DATA_TYPE_FSTRING");
          ErrCount++;
          break;
        }

      dst = data.fstring;
      cp++;
      end = l_card + FITS_CARD_SIZE - 1;
      for (;;)   /* Search for trailing quote */
        {
          if (*cp != '\'')    /* All characters but quote are used. */
            {
              *(dst++) = *cp;
            }
          else                /* Maybe there is a quote in the string */
            {
              if (cp >= end)
                break;  /* End of card ? finished */

              if (*(cp+1) != '\'')
                break;

              *(dst++) = *(cp++);
            }

          if (cp >= end)
            break;

          cp++;
        }

      *dst = '\0';
      break;
    }

  return (ErrCount == 0) ? &data : NULL;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_search_card - search a card in the record list           */
/*                                                                           */
/* Parameters:                                                               */
/* FitsRecordList *rl  [I] : record list to search                           */
/* char *keyword         [I] : keyword identifying the card                  */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* A card is searched in the record list. Only the first eight characters of */
/* keyword are significant. If keyword is less than 8 characters, its filled */
/* with blanks.                                                              */
/* If the card is found, a pointer to the card is returned.                  */
/* The pointer does not point to a null-terminated string. Only the next     */
/* 80 bytes are allowed to be read.                                          */
/* On failure a NULL-pointer is returned.                                    */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gchar *
fits_search_card (FitsRecordList *rl,
                  gchar          *keyword)
{
  gint  key_len, k;
  gchar key[9];

  key_len = strlen (keyword);
  if (key_len > 8)
    key_len = 8;
  if (key_len == 0)
    FITS_RETURN ("fits_search_card: Invalid parameter", NULL);

  strcpy (key, "        ");
  memcpy (key, keyword, key_len);

  while (rl != NULL)
    {
      gchar *card = (gchar *) rl->data;

      for (k = 0; k < FITS_RECORD_SIZE / FITS_CARD_SIZE; k++)
        {
          if (strncmp (card, key, 8) == 0)
            return (card);

          card += FITS_CARD_SIZE;
        }

      rl = rl->next_record;
    }

  return NULL;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_image_info - get information about an image              */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff         [I] : FITS file structure                            */
/* int picind            [I] : Index of picture in file (1,2,...)            */
/* int *hdupicind        [O] : Index of picture in HDU (1,2,...)             */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function returns on success a pointer to a FitsHduList. hdupicind     */
/* then gives the index of the image within the HDU.                         */
/* On failure, NULL is returned.                                             */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

FitsHduList *
fits_image_info (FitsFile *ff,
                 gint      picind,
                 gint     *hdupicind)
{
  FitsHduList *hdulist;
  gint         firstpic, lastpic;

  if (ff == NULL)
    FITS_RETURN ("fits_image_info: ff is NULL", NULL);

  if (ff->openmode != 'r')
    FITS_RETURN ("fits_image_info: file not open for reading", NULL);

  if ((picind < 1) || (picind > ff->n_pic))
    FITS_RETURN ("fits_image_info: picind out of range", NULL);

  firstpic = 1;
  for (hdulist = ff->hdu_list; hdulist != NULL; hdulist = hdulist->next_hdu)
    {
      if (hdulist->numpic <= 0)
        continue;

      lastpic = firstpic + hdulist->numpic - 1;

      if (picind <= lastpic)  /* Found image in current HDU ? */
        break;

      firstpic = lastpic + 1;
    }

  *hdupicind = picind - firstpic + 1;

  return hdulist;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_seek_image - position to a specific image                */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff         [I] : FITS file structure                            */
/* int picind            [I] : Index of picture to seek (1,2,...)            */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function positions the file pointer to a specified image.             */
/* The function returns on success a pointer to a FitsHduList. This pointer  */
/* must also be used when reading data from the image.                       */
/* On failure, NULL is returned.                                             */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

FitsHduList *
fits_seek_image (FitsFile *ff,
                 gint      picind)
{
  FitsHduList *hdulist;
  gint         hdupicind;
  glong        offset, pic_size;

  hdulist = fits_image_info (ff, picind, &hdupicind);
  if (hdulist == NULL)
    return NULL;

  pic_size = hdulist->bpp * hdulist->naxisn[0] * hdulist->naxisn[1];
  offset = hdulist->data_offset + (hdupicind - 1) * pic_size;
  if (fseek (ff->fp, offset, SEEK_SET) < 0)
    FITS_RETURN ("fits_seek_image: Unable to position to image", NULL);

  return hdulist;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_read_pixel - read pixel values from a file               */
/*                                                                           */
/* Parameters:                                                               */
/* FitsFile *ff           [I] : FITS file structure                          */
/* FitsHduList *hdulist  [I] : pointer to hdulist that describes image       */
/* int npix                [I] : number of pixel values to read              */
/* FitsPixTransform *trans [I]: pixel transformation                         */
/* void *buf               [O] : buffer where to place transformed pixels    */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function reads npix pixel values from the file, transforms them       */
/* checking for blank/NaN pixels and stores the transformed values in buf.   */
/* The number of transformed pixels is returned. If the returned value is    */
/* less than npix (or even -1), an error has occurred.                       */
/* hdulist must be a pointer returned by fits_seek_image(). Before starting  */
/* to read an image, fits_seek_image() must be called. Even for successive   */
/* images.                                                                   */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gint
fits_read_pixel (FitsFile         *ff,
                 FitsHduList      *hdulist,
                 gint              npix,
                 FitsPixTransform *trans,
                 void             *buf)
{
  gdouble  offs, scale;
  gdouble  datadiff, pixdiff;
  guchar   pixbuffer[4096];
  guchar  *pix;
  glong    creplace;
  gint     transcount = 0;
  glong    tdata, tmin, tmax;
  gint     maxelem;

  if (ff->openmode != 'r')
    return -1;   /* Not open for reading */

  if (trans->dsttyp != 'k')
    return -1;  /* Currently we only return types equivalent to the image format */

  if (npix <= 0)
    return npix;

  datadiff = trans->datamax - trans->datamin;
  pixdiff  = trans->pixmax - trans->pixmin;

  offs  = trans->datamin - trans->pixmin * datadiff / pixdiff;
  scale = datadiff / pixdiff;

  tmin = (glong) trans->datamin;
  tmax = (glong) trans->datamax;

  creplace = (glong) trans->replacement;

  switch (hdulist->bitpix)
    {
    case 8:
      {
        guchar *cdata = (guchar *) buf;
        while (npix > 0)  /* For all pixels to read */
          {
            FitsBitpix8 bp8, bp8blank;

            maxelem = sizeof (pixbuffer) / hdulist->bpp;
            if (maxelem > npix)
              maxelem = npix;

            if (fread ((gchar *) pixbuffer, hdulist->bpp,
                       maxelem, ff->fp) != maxelem)
              return -1;

            npix -= maxelem;

            pix = pixbuffer;

            if (hdulist->used.blank)
              {
                bp8blank = (FitsBitpix8) hdulist->blank;

                while (maxelem--)
                  {
                    bp8 = (FitsBitpix8) * (pix++);

                    if (bp8 == bp8blank)      /* Is it a blank pixel ? */
                      {
                        *(cdata++) = (guchar) creplace;
                      }
                    else                      /* Do transform */
                      {
                        tdata = (glong) (bp8 * scale + offs);
                        tdata = CLAMP (tdata, tmin, tmax);

                        *(cdata++) = (guchar) tdata;
                      }

                    transcount++;
                  }
              }
            else
              {
                while (maxelem--)
                  {
                    bp8 = (FitsBitpix8) * (pix++);

                    tdata = (glong) (bp8 * scale + offs);
                    tdata = CLAMP (tdata, tmin, tmax);

                    *(cdata++) = (guchar) tdata;

                    transcount++;
                  }
              }
          }
      }
      break;

    case 16:
      {
        FitsBitpix16 *cdata = (FitsBitpix16 *) buf;
        while (npix > 0)  /* For all pixels to read */
          {
            FitsBitpix16 bp16, bp16blank;

            maxelem = sizeof (pixbuffer) / hdulist->bpp;
            if (maxelem > npix)
              maxelem = npix;

            if (fread ((gchar *) pixbuffer, hdulist->bpp,
                       maxelem, ff->fp) != maxelem)
              return -1;

            npix -= maxelem;

            pix = pixbuffer;
            if (hdulist->used.blank)
              {
                bp16blank = (FitsBitpix16) hdulist->blank;

                while (maxelem--)
                  {
                    FITS_GETBITPIX16 (pix, bp16);

                    if (bp16 == bp16blank)
                      {
                        *(cdata++) = (FitsBitpix16) creplace;
                      }
                    else
                      {
                        tdata = (glong) (bp16 * scale + offs);

                        if (tdata < tmin)
                          tdata = tmin;
                        else if (tdata > tmax)
                          tdata = tmax;

                        *(cdata++) = (FitsBitpix16) tdata;
                      }

                    transcount++;
                    pix += 2;
                  }
              }
            else
              {
                while (maxelem--)
                  {
                    FITS_GETBITPIX16 (pix, bp16);

                    tdata = (glong) (bp16 * scale + offs);
                    if (tdata < tmin)
                      tdata = tmin;
                    else if (tdata > tmax)
                      tdata = tmax;

                    *(cdata++) = (FitsBitpix16) tdata;

                    transcount++;
                    pix += 2;
                  }
              }
          }
      }
      break;

    case 32:
      {
        FitsBitpix32 *cdata = (FitsBitpix32 *) buf;
        while (npix > 0)  /* For all pixels to read */
          {
            FitsBitpix32 bp32, bp32blank;

            maxelem = sizeof (pixbuffer) / hdulist->bpp;
            if (maxelem > npix)
              maxelem = npix;

            if (fread ((gchar *) pixbuffer, hdulist->bpp,
                       maxelem, ff->fp) != maxelem)
              return -1;

            npix -= maxelem;

            pix = pixbuffer;
            if (hdulist->used.blank)
              {
                bp32blank = (FitsBitpix32) hdulist->blank;

                while (maxelem--)
                  {
                    FITS_GETBITPIX32 (pix, bp32);

                    if (bp32 == bp32blank)
                      {
                        *(cdata++) = (FitsBitpix32) creplace;
                      }
                    else
                      {
                        tdata = (glong) (bp32 * scale + offs);
                        if (tdata < tmin)
                          tdata = tmin;
                        else if (tdata > tmax)
                          tdata = tmax;

                        *(cdata++) = (FitsBitpix32) tdata;
                      }

                    transcount++;
                    pix += 4;
                  }
              }
            else
              {
                while (maxelem--)
                  {
                    FITS_GETBITPIX32 (pix, bp32);

                    tdata = (glong) (bp32 * scale + offs);
                    tdata = CLAMP (tdata, tmin, tmax);

                    *(cdata++) = (FitsBitpix32) tdata;

                    transcount++;
                    pix += 4;
                  }
              }
          }
      }
      break;

    case -32:
      {
        FitsBitpixM32 *cdata = (FitsBitpixM32 *) buf;
        while (npix > 0)  /* For all pixels to read */
          {
            FitsBitpixM32 bpm32 = 0;

            maxelem = sizeof (pixbuffer) / hdulist->bpp;
            if (maxelem > npix)
              maxelem = npix;

            if (fread ((gchar *) pixbuffer, hdulist->bpp,
                       maxelem, ff->fp) != maxelem)
              return -1;

            npix -= maxelem;

            pix = pixbuffer;
            while (maxelem--)
              {
                if (fits_nan_32 (pix))    /* An IEEE special value ? */
                  {
                    *(cdata++) = trans->replacement;
                  }
                else                      /* Do transform */
                  {
                    FITS_GETBITPIXM32 (pix, bpm32);

                    bpm32 = bpm32 * scale + offs;
                    bpm32 = CLAMP (bpm32, trans->datamin, trans->datamax);

                    *(cdata++) = bpm32;
                  }

                transcount++;
                pix += 4;
              }
          }
      }
      break;

    case -64:
      {
        FitsBitpixM64 *cdata = (FitsBitpixM64 *) buf;
        while (npix > 0)  /* For all pixels to read */
          {
            FitsBitpixM64 bpm64;

            maxelem = sizeof (pixbuffer) / hdulist->bpp;
            if (maxelem > npix)
              maxelem = npix;

            if (fread ((gchar *) pixbuffer, hdulist->bpp,
                       maxelem, ff->fp) != maxelem)
              return -1;

            npix -= maxelem;

            pix = pixbuffer;
            while (maxelem--)
              {
                if (fits_nan_64 (pix))
                  {
                    *(cdata++) = trans->replacement;
                  }
                else
                  {
                    FITS_GETBITPIXM64 (pix, bpm64);

                    bpm64 = bpm64 * scale + offs;
                    bpm64 = CLAMP (bpm64, trans->datamin, trans->datamax);

                    *(cdata++) = bpm64;
                  }

                transcount++;
                pix += 8;
              }
          }
      }
      break;
    }

  return transcount;
}


#ifndef FITS_NO_DEMO

/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : fits_to_pgmraw - convert FITS-file to raw PGM-file            */
/*                                                                           */
/* Parameters:                                                               */
/* char *fitsfile          [I] : name of fitsfile                            */
/* char *pgmfile           [I] : name of pgmfile                             */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function converts a FITS-file to a raw PGM-file. The PGM-file will    */
/* be upside down, because the orientation for storing the image is          */
/* different. On success, 0 is returned. On failure, -1 is returned.         */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gint
fits_to_pgmraw (gchar *fitsfile,
                gchar *pgmfile)
{
  FitsFile         *fitsin = NULL;
  FILE             *pgmout = NULL;
  FitsHduList      *hdu;
  FitsPixTransform  trans;
  gint              retval = -1, nbytes, maxbytes;
  gchar             buffer[1024];

  fitsin = fits_open (fitsfile, "r");  /* Open FITS-file for reading */
  if (fitsin == NULL)
    goto err_return;

  if (fitsin->n_pic < 1)
    goto err_return;  /* Any picture in it ? */

  hdu = fits_seek_image (fitsin, 1);       /* Position to the first image */
  if (hdu == NULL)
    goto err_return;

  if (hdu->naxis < 2)
    goto err_return;     /* Enough dimensions ? */

  pgmout = g_fopen (pgmfile, "wb");
  if (pgmout == NULL)
    goto err_return;

  /* Write PGM header with width/height */
  fprintf (pgmout, "P5\n%d %d\n255\n", hdu->naxisn[0], hdu->naxisn[1]);

  /* Set up transformation for FITS pixel values to 0...255 */
  /* It maps trans.pixmin to trans.datamin and trans.pixmax to trans.datamax. */
  /* Values out of range [datamin, datamax] are clamped */
  trans.pixmin      = hdu->pixmin;
  trans.pixmax      = hdu->pixmax;
  trans.datamin     = 0.0;
  trans.datamax     = 255.0;
  trans.replacement = 0.0;  /* Blank/NaN replacement value */
  trans.dsttyp      = 'c';       /* Output type is character */

  nbytes = hdu->naxisn[0]*hdu->naxisn[1];
  while (nbytes > 0)
    {
      maxbytes = sizeof (buffer);
      if (maxbytes > nbytes)
        maxbytes = nbytes;

      /* Read pixels and transform them */
      if (fits_read_pixel (fitsin, hdu, maxbytes, &trans, buffer) != maxbytes)
        goto err_return;

      if (fwrite (buffer, 1, maxbytes, pgmout) != maxbytes)
        goto err_return;

      nbytes -= maxbytes;
    }

  retval = 0;

 err_return:

  if (fitsin)
    fits_close (fitsin);

  if (pgmout)
    fclose (pgmout);

  return retval;
}


/*****************************************************************************/
/* #BEG-PAR                                                                  */
/*                                                                           */
/* Function  : pgmraw to fits - convert raw PGM-file to FITS-file            */
/*                                                                           */
/* Parameters:                                                               */
/* char *pgmfile           [I] : name of pgmfile                             */
/* char *fitsfile          [I] : name of fitsfile                            */
/*                  ( mode : I=input, O=output, I/O=input/output )           */
/*                                                                           */
/* The function converts a raw PGM-file to a FITS-file. The FITS-file will   */
/* be upside down, because the orientation for storing the image is          */
/* different. On success, 0 is returned. On failure, -1 is returned.         */
/*                                                                           */
/* #END-PAR                                                                  */
/*****************************************************************************/

gint
pgmraw_to_fits (gchar *pgmfile,
                gchar *fitsfile)
{
  FitsFile    *fitsout = NULL;
  FILE        *pgmin   = NULL;
  FitsHduList *hdu;
  gchar        buffer[1024];
  gint         width, height, numbytes, maxbytes;
  gint         retval = -1;

  fitsout = fits_open (fitsfile, "w");
  if (fitsout == NULL)
    goto err_return;

  pgmin = g_fopen (pgmfile, "r");
  if (pgmin == NULL)
    goto err_return;

  /* Read signature of PGM file */
  if (fgets (buffer, sizeof (buffer), pgmin) == NULL)
    goto err_return;

  if ((buffer[0] != 'P') || (buffer[1] != '5'))
    goto err_return;

  /* Skip comments up to width/height */
  do
    {
      if (fgets (buffer, sizeof (buffer), pgmin) == NULL)
        goto err_return;
    }
  while (buffer[0] == '#');

  if (sscanf (buffer, "%d%d", &width, &height) != 2)
    goto err_return;

  if ((width < 1) || (height < 1))
    goto err_return;

  /* Skip comments up to maxval */
  do
    {
      if (fgets (buffer, sizeof (buffer), pgmin) == NULL)
        goto err_return;
    }
  while (buffer[0] == '#');

  /* Ignore maxval */

  hdu = fits_add_hdu (fitsout);     /* Create a HDU for the FITS file */
  if (hdu == NULL)
    goto err_return;

  hdu->used.simple  = 1;         /* Set proper values */
  hdu->bitpix       = 8;
  hdu->naxis        = 2;
  hdu->naxisn[0]    = width;
  hdu->naxisn[1]    = height;
  hdu->used.datamin = 1;
  hdu->datamin      = 0.0;
  hdu->used.datamax = 1;
  hdu->datamax      = 255.0;
  hdu->used.bzero   = 1;
  hdu->bzero        = 0.0;
  hdu->used.bscale  = 1;
  hdu->bscale       = 1.0;

  fits_add_card (hdu, "");
  fits_add_card (hdu,
                 "HISTORY THIS FITS FILE WAS GENERATED BY FITSRW "
                 "USING PGMRAW_TO_FITS");

  /* Write the header. Blocking is done automatically */
  if (fits_write_header (fitsout, hdu) < 0)
    goto err_return;

  /* The primary array plus blocking must be written manually */
  numbytes = width * height;

  while (numbytes > 0)
    {
      maxbytes = sizeof (buffer);
      if (maxbytes > numbytes)
        maxbytes = numbytes;

      if (fread (buffer, 1, maxbytes, pgmin) != maxbytes)
        goto err_return;

      if (fwrite (buffer, 1, maxbytes, fitsout->fp) != maxbytes)
        goto err_return;

      numbytes -= maxbytes;
    }

  /* Do blocking */
  numbytes = (width * height) % FITS_RECORD_SIZE;
  if (numbytes)
    {
      while (numbytes++ < FITS_RECORD_SIZE)
        if (putc (0, fitsout->fp) == EOF)
          goto err_return;
    }

  retval = 0;

 err_return:

  if (fitsout)
    fits_close (fitsout);

  if (pgmin)
    fclose (pgmin);

  return retval;
}

#endif /* ! FITS_NO_DEMO */
