adds alternative path to libtango and adds (missing?) linker reference to libcfitsio

#include <stdio.h>

#include <string>

#include <boost/filesystem.hpp>

#include <openssl/md5.h>

#include "fitsio.h"

// computes datasum over DataUnits of all HDU's of a FITS-file

int hdu_count(const char * filename)

{

  int lasthdu = 0;/* hdu count: 1..lasthdu */

  int status = 0;

  fitsfile *fptr;

  if( fits_open_file(&fptr, filename, READONLY, &status) ) goto f_end;

  if( fits_get_num_hdus(fptr, &lasthdu, &status) ) goto f_end; 

f_end:

  fits_close_file(fptr, &status);// no err check, we read only 

  return lasthdu;

}

struct du_offs

{

	long int datastart;

	long int dataend;

};

void init_du_offsets(int nhdu, struct du_offs * duoffs)

{

  for (int ix = 0; ix < nhdu; ix++)

  {

	duoffs[ix].datastart = (long int)0; 

	duoffs[ix].dataend   = (long int)0;

  } 

}

int du_offsets(const char * filename, int nhdu, struct du_offs * duoffs)

{

  int status = 0;

  fitsfile *fptr;

  int hdunum, hdutype;

  if( fits_open_file(&fptr, filename, READONLY, &status) ) goto f_end;

  for (hdunum = 1; hdunum <= nhdu; hdunum++)

  {

            if ( fits_movabs_hdu(fptr, hdunum, &hdutype, &status) ) goto f_end;

    	    LONGLONG headstart, datastart, dataend;

            if( fits_get_hduaddrll (fptr, &headstart, &datastart, &dataend, &status) ) goto f_end;

	    int ix = hdunum - 1;

 	    // FIXME cast LONGLONG -> long int (here both 64 bit)

	    duoffs[ix].datastart = (long int)datastart;	    

	    duoffs[ix].dataend   = (long int)dataend;

  }

f_end:

  fits_close_file(fptr, &status);// no err check, we read only 

  return status;

}

std::string calcDigest(const char * filename, int nhdu, struct du_offs * duoffs)

{

  char mdString[33] = "";

  unsigned char digest[MD5_DIGEST_LENGTH];

  int nbytes, hdunum;

  unsigned char block[2880];

  FILE *inFile = fopen(filename,"rb");

  if(inFile == NULL) goto f_end;

  MD5_CTX mdContext;

  MD5_Init (&mdContext);

  for (hdunum = 1; hdunum <= nhdu; hdunum++)

  {

	    int ix = hdunum - 1;

	    long int datastart = duoffs[ix].datastart;

	    long int dataend   = duoffs[ix].dataend;

            long int nrec = (dataend - datastart) / 2880;

	    if(nrec > 0)

            {

                    // backup

                    long int offbup = ftell(inFile);

		    if(offbup <0) goto f_end;

                    // accumulate over DUs

                    if(0 != fseek(inFile,datastart,SEEK_SET)) goto f_end;

                    for(long int r=0; r<nrec; r++)

                    {

                        nbytes = fread (block, 1, 2880, inFile);

                        if(nbytes != 2880)

			{

				MD5_Final(digest,&mdContext);

				goto f_end;

			}

                        MD5_Update (&mdContext, block, nbytes);

                    }

                    // restore

                    if(0 != fseek(inFile,offbup,SEEK_SET)) goto f_end;

           }

  }

  MD5_Final (digest,&mdContext);

  /* convert digest to string */

  int i;

  for(i = 0; i < MD5_DIGEST_LENGTH; i++)

       sprintf(&mdString[i*2], "%02x", (unsigned int)digest[i]);

f_end:

  fclose (inFile);

  return mdString;

}

std::string compute_dataunitsum(const std::string& fileName)

{

  const char *filename = fileName.c_str();

  const int hducnt = hdu_count(filename);

  struct du_offs * duoffs = new struct du_offs[hducnt];

  init_du_offsets(hducnt,duoffs);

  int rc = du_offsets(filename, hducnt, duoffs);

  if(rc == 0)

  {

  	std::string dusum = calcDigest(filename, hducnt, duoffs);

  	delete[] duoffs;

	return dusum;

  }

  else

  {

  	delete[] duoffs;

	return "";

  }

}

#ifndef FILEDATASUM_H

#define FILEDATASUM_H

#ifdef __cplusplus

// extern "C" {

#endif

// computes datasum over all DataUnits of a FITS-file

// should any error occur, returns empty string

std::string compute_dataunitsum(const std::string& fileName);

#ifdef __cplusplus

//}

#endif

#endif