#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "fitsio.h"

#define LINEPIX 2100

void printerror( int status );

int main(int argc, char *argv[])
{
  fitsfile *fp;
  int i,j,status,nfound,anynull,bitpix=-32;
  long fpixel, nelements,naxis=2;
  long naxes[2]={LINEPIX, LINEPIX},nbuffer;
  float nullval;
  static float buffer[LINEPIX],z[LINEPIX][LINEPIX];
  int qf,qt,ifo,ifs,jfo,jfs,ito,its,jto,jts;
  float val;

  if(argc!=4){
    fprintf(stderr,"Usage : %s input_file #quad_from #quad_to\n",argv[0]);
    exit(0);
  }
  sscanf(argv[2],"%f",&val);
  if(fabs(val-1)<1e-5) qf=1;
  else if(fabs(val-2)<1e-5) qf=2;
  else if(fabs(val-3)<1e-5) qf=3;
  else if(fabs(val-4)<1e-5) qf=4;
  else qf=0;
  sscanf(argv[3],"%d",&qt);

  fprintf(stderr,"Read %s  ... ",argv[1]);

  status=0;
  if(fits_open_file(&fp,argv[1], READONLY, &status))
    printerror(status);
  if(fits_read_keys_lng(fp, "NAXIS", 1, 2, naxes, &nfound, &status))
    printerror(status);
  fprintf(stderr,"%ld x %ld format ",naxes[0],naxes[1]);
  if((naxes[0]>LINEPIX)||(naxes[1]>LINEPIX)){
    fprintf(stderr,"\nIllegal image format\n");
    exit(0);
  }
  fpixel = 1;
  nullval = 0;
  nbuffer = naxes[0];
  for(i=0;i<naxes[1];i++){
    if (fits_read_img(fp, TFLOAT, fpixel, nbuffer, &nullval,
                      buffer, &anynull, &status))
      printerror(status);
    for(j=0;j<naxes[0];j++) z[i][j]=buffer[j];
    fpixel+=naxes[0];
  }
  if(fits_close_file(fp, &status))
    printerror(status);
  fprintf(stderr,"OK\n");

  if(qf==2){ifo=0;ifs=1;jfo=naxes[0]-1;jfs=-1;}
  else if(qf==3){ifo=naxes[1]-1;ifs=-1;jfo=0;jfs=1;}
  else if(qf==4){ifo=naxes[1]-1;ifs=-1;jfo=naxes[0]-1;jfs=-1;}
  else {ifo=0;ifs=1;jfo=0;jfs=1;}
  if(qt==2){ito=0;its=1;jto=naxes[0]-1;jts=-1;}
  else if(qt==3){ito=naxes[1]-1;its=-1;jto=0;jts=1;}
  else if(qt==4){ito=naxes[1]-1;its=-1;jto=naxes[0]-1;jts=-1;}
  else {ito=0;its=1;jto=0;jts=1;}
  for(i=0;i<naxes[1]/2;i++){
    for(j=0;j<naxes[0]/2;j++){
      if(qf>0 && qf<5) z[ito+its*i][jto+jts*j]=z[ifo+ifs*i][jfo+jfs*j];
      else z[ito+its*i][jto+jts*j]=val;
    }
  }

  remove(argv[1]);
  fprintf(stderr,"Write %s  ... ",argv[1]);
  status=0;
  if (fits_create_file(&fp, argv[1], &status))
    printerror(status);
  if (fits_create_img(fp, bitpix, naxis, naxes, &status))
    printerror(status);
  fpixel=1;
  nelements=naxes[0];
  for(i=0;i<naxes[1];i++){
    if (fits_write_img(fp, TFLOAT, fpixel, nelements, z[i], &status))
      printerror(status);
    fpixel+=naxes[0];
  }
  if (fits_close_file(fp, &status))
    printerror(status);
  fprintf(stderr,"OK\n");
  return(0);
}

void printerror( int status)
{
    /*****************************************************/
    /* Print out cfitsio error messages and exit program */
    /*****************************************************/

    char status_str[FLEN_STATUS], errmsg[FLEN_ERRMSG];

    if (status)
      fprintf(stderr, "\n*** Error occurred during program execution ***\n");

    fits_get_errstatus(status, status_str);   /* get the error description */
    fprintf(stderr, "\nstatus = %d: %s\n", status, status_str);

    /* get first message; null if stack is empty */
    if ( fits_read_errmsg(errmsg) )
    {
         fprintf(stderr, "\nError message stack:\n");
         fprintf(stderr, " %s\n", errmsg);

         while ( fits_read_errmsg(errmsg) )  /* get remaining messages */
             fprintf(stderr, " %s\n", errmsg);
    }

    exit( status );       /* terminate the program, returning error status */
}