base64_reader.h

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/* ./dumper/base64_reader.h 
**********************************
Copyright INRIA and CEA 

author : Guillaume ANCIAUX (anciaux@labri.fr, g.anciaux@laposte.net)

The LibMultiScale is a C++ parallel framework for the multiscale
coupling methods dedicated to material simulations. This framework
provides an API which makes it possible to program coupled simulations
and integration of already existing codes.

This Project is done in a collaboration between INRIA Futurs Bordeaux
within ScAlApplix team and CEA/DPTA Ile de France. 

This software is governed by the CeCILL-C license under French law and
abiding by the rules of distribution of free software.  You can  use, 
modify and/ or redistribute the software under the terms of the CeCILL-C
license as circulated by CEA, CNRS and INRIA at the following URL
"http://www.cecill.info". 

As a counterpart to the access to the source code and  rights to copy,
modify and redistribute granted by the license, users are provided only
with a limited warranty  and the software's author,  the holder of the
economic rights,  and the successive licensors  have only  limited
liability. 

In this respect, the user's attention is drawn to the risks associated
with loading,  using,  modifying and/or developing or reproducing the
software by the user in light of its specific status of free software,
that may mean  that it is complicated to manipulate,  and  that  also
therefore means  that it is reserved for developers  and  experienced
professionals having in-depth computer knowledge. Users are therefore
encouraged to load and test the software's suitability as regards their
requirements in conditions enabling the security of their systems and/or 
data to be ensured and,  more generally, to use and operate it in the 
same conditions as regards security. 

The fact that you are presently reading this means that you have had
knowledge of the CeCILL-C license and that you accept its terms.
***********************************/

#ifndef BASE64_READER_H
#define BASE64_READER_H

class Base64Reader{

 public:
  
  Base64Reader(){
    InitBase64Stuff();
    n = 0;
    n_coded = 0;
    read_bytes_in_double=0;
  };
  
  int PopDoubleInBase64(double & c);
  int PopIntegerInBase64(int & c);
  int PopByteInBase64(unsigned char & c);
  int Decode(unsigned char c0,unsigned char c1,unsigned char c2,unsigned char c3,
              unsigned char * r0,unsigned char * r1,unsigned char * r2);

  void SetStream(char * str,int l);

 private:

  void InitBase64Stuff();
  char dtable[256];
  char etable[256];
  int n;
  int n_coded;
  unsigned char igroup[3],ogroup[4];


  char * start_ptr;
  char * current_ptr;
  int len;
  unsigned char read_byte[3];
  char read_coded_byte[4];
    

  double temp_double;
  int read_bytes_in_double;
};



inline void Base64Reader::SetStream(char * str,int l){
  current_ptr = str;
  start_ptr = str;
  len = l;

  DUMP("n_coded " << n_coded,DBG_DETAIL);
  if (n_coded > 0){
    //je relie l'ancien stream et le nouveau
    
    if (n_coded == 1 && current_ptr < start_ptr+len) {
      read_coded_byte[1] = *current_ptr;
      ++n_coded;
      ++current_ptr;
    }
    DUMP("n_coded " << n_coded,DBG_DETAIL);
    if (n_coded == 2 && current_ptr < start_ptr+len) {
      read_coded_byte[2] = *current_ptr;
      ++n_coded;
      ++current_ptr;
    }
    DUMP("n_coded " << n_coded,DBG_DETAIL);
    if (n_coded == 3 && current_ptr < start_ptr+len) {
      read_coded_byte[3] = *current_ptr;
      ++n_coded;
      ++current_ptr;
    }
    DUMP("n_coded " << n_coded,DBG_DETAIL);
  }
  

};


inline int Base64Reader::PopIntegerInBase64(int & d){
  int read = 1;

  DUMP("pushing " << d << " ( n = " << n << " )",DBG_DETAIL);
  unsigned char * c = (unsigned char*)&d;
  for (unsigned int i = 0 ; i < sizeof(int) ; ++i){
    read &= PopByteInBase64(c[i]);
    if (!read) break;
  }
  return read;
}

/* inline void Base64Reader::PopStrInBase64(char * str){ */

/*   FATAL("unimplemented for the moment"); */
/* } */

inline int Base64Reader::PopDoubleInBase64(double & d){
  int read = 1;
  DUMP("pop double , already red  = " << read_bytes_in_double,DBG_DETAIL);

  unsigned char * c = (unsigned char*)&temp_double;
  for (unsigned int i = read_bytes_in_double ; i < sizeof(double) ; ++i){
    read &= PopByteInBase64(c[i]);
    if (read) ++read_bytes_in_double;
    if (!read) break;
  }

  if (read) {
    read_bytes_in_double = 0;
    d = temp_double;
    DUMP("readed double " << d,DBG_DETAIL);
  }
  return read;
}

inline int Base64Reader::PopByteInBase64(unsigned char & c){
  //initialise les blocs
  if (n < 0 || n > 3) FATAL("this should not append check source code");

  DUMP("pop byte",DBG_DETAIL);
    
  // si je suis a n = 3 je dois relire 4 octets de base64
  if (n == 0){

    DUMP("n_coded " << n_coded,DBG_DETAIL);
    if (n_coded == 0){
      if (current_ptr < start_ptr+len) {read_coded_byte[0] = current_ptr[0];++n_coded;DUMP("n_coded " << n_coded,DBG_DETAIL);}
      else {DUMP("lala" << n_coded,DBG_DETAIL);return 0;}
      if (current_ptr+1 < start_ptr+len) {read_coded_byte[1] = current_ptr[1];++n_coded;DUMP("n_coded " << n_coded,DBG_DETAIL);}
      else {DUMP("lala" << n_coded,DBG_DETAIL);return 0;}
      if (current_ptr+2 < start_ptr+len) {read_coded_byte[2] = current_ptr[2];++n_coded;DUMP("n_coded " << n_coded,DBG_DETAIL);}
      else {DUMP("lala" << n_coded,DBG_DETAIL);return 0;}
      if (current_ptr+3 < start_ptr+len) {read_coded_byte[3] = current_ptr[3];++n_coded;DUMP("n_coded " << n_coded,DBG_DETAIL);}
      else {DUMP("lala" << n_coded,DBG_DETAIL);return 0;}
      current_ptr+=4;
    }
  }
  
  if (n_coded == 4)
    Decode(read_coded_byte[0],read_coded_byte[1],read_coded_byte[2],read_coded_byte[3],
           &read_byte[0],&read_byte[1],&read_byte[2]);
  
  c = read_byte[n];

  DUMP("readed charater "<< (int)c,DBG_DETAIL);
  ++n;

  if (n == 3) {
    n = 0;
    n_coded = 0;
  }
  return 1;

}


inline int Base64Reader::Decode(unsigned char c0,unsigned char c1,unsigned char c2,unsigned char c3,
                                 unsigned char * r0,unsigned char * r1,unsigned char * r2){

  unsigned char d0, d1, d2, d3;

  d0 = dtable[0+c0];
  d1 = dtable[0+c1];
  d2 = dtable[0+c2];
  d3 = dtable[0+c3];

  

  DUMP("d0 " << (int)d0 << " d1 " << (int)d1 << " d2 " << (int)d2 << " d3 " << (int)d3,DBG_DETAIL);
  
  // Decode the 3 bytes

  *r0 = ((d0 << 2) & 0xFC) | ((d1 >> 4) & 0x03);
  *r1 = ((d1 << 4) & 0xF0) | ((d2 >> 2) & 0x0F);
  *r2 = ((d2 << 6) & 0xC0) | ((d3 >> 0) & 0x3F);

  DUMP("r0 " << (int)*r0 << " r1 " << (int)*r1 << " r2 " << (int)*r2,DBG_DETAIL);
  
  // Return the number of bytes actually decoded

  if (c2 == '=') 
    { 
    return 1; 
    }
  if (c3 == '=') 
    { 
    return 2; 
    }
  return 3;
}



inline void Base64Reader::InitBase64Stuff(){
  memset(dtable,0xFF,256);
  memset(etable,0xFF,256);

  for(int i=0;i<9;i++){
    etable[i]= 'A'+i;
    dtable[0+etable[i]] = i;
    etable[i+9]= 'J'+i;
    dtable[0+etable[i+9]] = i+9;
    etable[26+i]= 'a'+i;
    dtable[0+etable[26+i]] = i + 26;
    etable[26+i+9]= 'j'+i;
    dtable[0+etable[26+i+9]] = i + 26 + 9;
  }
  for(int i= 0;i<8;i++){
    etable[i+18]= 'S'+i;
    dtable[0+etable[i+18]] = i + 18;
    etable[26+i+18]= 's'+i;
    dtable[0+etable[26+i+18]] = 26 + i + 18;
  }
  for(int i= 0;i<10;i++){
    etable[52+i]= '0'+i;
    dtable[0+etable[i+52]] = i + 52;
  }
  etable[62]= '+';
  dtable[0+etable[62]] = 62;
  etable[63]= '/';
  dtable[0+etable[63]] = 63;
}

#endif //BASE64_WRITER_H

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