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base64_reader.hh
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/**
* @file base64_reader.hh
*
* @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
*
* @date creation: Thu Mar 11 2010
* @date last modification: Thu Nov 01 2012
*
* @brief header for base64 reader
*
*
* Copyright (©) 2010-2012, 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* IOHelper is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* IOHelper 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 Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with IOHelper. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef BASE64_READER_H
#define BASE64_READER_H
/** Class that allow to push binary data
in base64 format to any file.
This class is mainly used by the paraview helper
to create binary XML VTK files.
The conversion is a 4/3 size conversion. */
class Base64Reader{
public:
Base64Reader(){
InitBase64Stuff();
n = 0;
n_coded = 0;
read_bytes_in_double=0;
};
//! push to file a double
int PopDoubleInBase64(double & c);
//! push to file an integer
int PopIntegerInBase64(int & c);
//! push to file a Byte
int PopByteInBase64(unsigned char & c);
//! decode 3 bytes from 4 Base64 bytes (4/3 ratio)
int Decode(unsigned char c0,unsigned char c1,unsigned char c2,unsigned char c3,
unsigned char * r0,unsigned char * r1,unsigned char * r2);
//! set the reading stream
void SetStream(char * str,int l);
private:
//! initialisation process
void InitBase64Stuff();
//! decoding table
char dtable[256];
//! encoding table
char etable[256];
//! stage in conversion process(1,2 or 3)
int n;
//! stage for coded bytes
int n_coded;
//! used to code/decode
unsigned char igroup[3],ogroup[4];
//! starting stream position
char * start_ptr;
//! last reading position
char * current_ptr;
//! size of the stream
int len;
//! readed bytes
unsigned char read_byte[3];
//! readed bytes but still coded
char read_coded_byte[4];
//! temporary double
double temp_double;
//! readed bytes in 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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