fread_be.C

/*
 *  Read binary data from a file according to the Big Endian convention
 *
 */

/*
 *   Copyright (c) 2001 Eric Gourgoulhon
 *
 *   This file is part of LORENE.
 *
 *   LORENE 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 2 of the License, or
 *   (at your option) any later version.
 *
 *   LORENE 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 LORENE; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

char fread_be_C[] = "$Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/fread_be.C,v 1.4 2009/01/19 15:23:17 j_novak Exp $" ;

/*
 * $Id: fread_be.C,v 1.4 2009/01/19 15:23:17 j_novak Exp $
 * $Log: fread_be.C,v $
 * Revision 1.4  2009/01/19 15:23:17  j_novak
 * Change of some casts to avoid warnings
 *
 * Revision 1.3  2008/08/19 06:42:01  j_novak
 * Minor modifications to avoid warnings with gcc 4.3. Most of them concern
 * cast-type operations, and constant strings that must be defined as const char*
 *
 * Revision 1.2  2001/12/13 15:01:19  e_gourgoulhon
 * Array bytes_big now created with a new char[]
 *
 * Revision 1.1  2001/12/04 21:32:39  e_gourgoulhon
 * Functions similar to the stdio fread/fwrite except that they ensure
 * the big endian convention, whatever the system convention is.
 *
 * Revision 1.1  2001/11/23 15:09:09  e_gourgoulhon
 * Templates for new source files
 *
 *
 * $Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/fread_be.C,v 1.4 2009/01/19 15:23:17 j_novak Exp $
 *
 */

// C headers
#include <stdio.h>
#include <assert.h>

            //-------------------------//
            //  int version        //
            //-------------------------//
            
int fread_be(int* aa, int size, int nb, FILE* fich) {

    assert(size == 4) ;
    
    // Determines whether the default storage is big endian
    //  or large endians
    
    int itest = 1 ;
    bool little_endian = ( *( reinterpret_cast<char*>(&itest) ) == 1) ;
    
    if (little_endian) {

        int size_tot = 4 * nb ;

        char* bytes_big = new char[size_tot] ;
        
        int nr = int(fread(bytes_big, 1, size_tot, fich)) ;
        
        char* pbig =  bytes_big ;
        char* plit = reinterpret_cast<char*>( aa );
        
        for (int j=0; j< nb; j++) {
        
            for (int i=0; i<4; i++) {
                plit[i] = pbig[3-i] ;
            }
        
            plit += 4 ;     // next item
            pbig += 4 ;
            
        }
        
        delete [] bytes_big ; 

        return nr / 4 ;     

    }
    else {  // Big endian case: nothing to do:
    
        return int(fread(aa, size, nb, fich)) ;
    }
        
}

            //-------------------------//
            //  double version     //
            //-------------------------//
            
int fread_be(double* aa, int size, int nb, FILE* fich) {

    assert(size == 8) ;
    
    // Determines whether the default storage is big endian
    //  or large endians
    
    int itest = 1 ;
    bool little_endian = ( *( reinterpret_cast<char*>(&itest) ) == 1) ;
    
    if (little_endian) {

        int size_tot = 8 * nb ;

        char* bytes_big = new char[size_tot] ;

        int nr = int(fread(bytes_big, 1, size_tot, fich)) ;
        
        char* pbig =  bytes_big ;
        char* plit = reinterpret_cast<char*>( aa );
        
        for (int j=0; j< nb; j++) {
        
            for (int i=0; i<8; i++) {
                plit[i] = pbig[7-i] ;
            }
        
            plit += 8 ;     // next item
            pbig += 8 ;
            
        }

        delete [] bytes_big ;

        return nr / 8 ;     
        
    }
    else {  // Big endian case: nothing to do:
    
        return int(fread(aa, size, nb, fich)) ;
    }
        
}

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