Base64 EN/DECode Source...

/*Base64.h*/
#ifndef __BASE64_H
#define __BASE64_H

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <string>

class CBase64
{
public:
 CBase64(void);
 ~CBase64(void);
 
 static std::string Decode( const std::string& data );
 static std::string Encode( const std::string& data );
};
#endif // __BASE64_H


============================================================================


/*Base64.cpp*/
#include "Base64.h"
#include <stdio.h>

using namespace std;

static const char           fillchar = '=';
static const string::size_type  np = string::npos;
static const string   Base64Table("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");         
 // Decode Table gives the index of any valid base64 character in the Base64 table]
 // 65 == A, 97 == a, 48 == 0, 43 == +, 47 == /

                                                // 0  1  2  3  4  5  6  7  8  9
const string::size_type DecodeTable[] =       {np,np,np,np,np,np,np,np,np,np,  // 0 - 9
                                               np,np,np,np,np,np,np,np,np,np,  //10 -19
                                               np,np,np,np,np,np,np,np,np,np,  //20 -29
                                               np,np,np,np,np,np,np,np,np,np,  //30 -39
                                               np,np,np,62,np,np,np,63,52,53,  //40 -49
                                               54,55,56,57,58,59,60,61,np,np,  //50 -59
                                               np,np,np,np,np, 0, 1, 2, 3, 4,  //60 -69
                                               5, 6, 7, 8, 9,10,11,12,13,14,  //70 -79
                                               15,16,17,18,19,20,21,22,23,24,  //80 -89
                                               25,np,np,np,np,np,np,26,27,28,  //90 -99
                                               29,30,31,32,33,34,35,36,37,38,  //100 -109
                                               39,40,41,42,43,44,45,46,47,48,  //110 -119
                                               49,50,51,np,np,np,np,np,np,np,  //120 -129
                                               np,np,np,np,np,np,np,np,np,np,  //130 -139
                                               np,np,np,np,np,np,np,np,np,np,  //140 -149
                                               np,np,np,np,np,np,np,np,np,np,  //150 -159
                                               np,np,np,np,np,np,np,np,np,np,  //160 -169
                                               np,np,np,np,np,np,np,np,np,np,  //170 -179
                                               np,np,np,np,np,np,np,np,np,np,  //180 -189
                                               np,np,np,np,np,np,np,np,np,np,  //190 -199
                                               np,np,np,np,np,np,np,np,np,np,  //200 -209
                                               np,np,np,np,np,np,np,np,np,np,  //210 -219
                                               np,np,np,np,np,np,np,np,np,np,  //220 -229
                                               np,np,np,np,np,np,np,np,np,np,  //230 -239
                                               np,np,np,np,np,np,np,np,np,np,  //240 -249
                                               np,np,np,np,np,np};             //250 -256

CBase64::CBase64(void)
{
}

CBase64::~CBase64(void)
{
}

string CBase64::Encode(const string& data)
{
 string::size_type  i;
 char               c;
 string::size_type  len = data.length();
 string             ret;
 
 ret.reserve(len * 2);
 
 for (i = 0; i < len; ++i)
 {
   c = (data[i] >> 2) & 0x3f;
   ret.append(1, Base64Table[c]);
   c = (data[i] << 4) & 0x3f;
   if (++i < len)
       c |= (data[i] >> 4) & 0x0f;
  
   ret.append(1, Base64Table[c]);
   if (i < len)
   {
       c = (data[i] << 2) & 0x3f;
       if (++i < len)
           c |= (data[i] >> 6) & 0x03;
  
       ret.append(1, Base64Table[c]);
   }
   else
   {
       ++i;
       ret.append(1, fillchar);
   }
  
   if (i < len)
   {
       c = data[i] & 0x3f;
       ret.append(1, Base64Table[c]);
   }
   else
   {
       ret.append(1, fillchar);
   }
 }
 
 return(ret);
}

string CBase64::Decode(const string& data)
{
 string::size_type  i;
 char               c;
 char                c1;
 string::size_type  len = data.length();
 string             ret;
 
 ret.reserve(len);
 
 for (i = 0; i < len; ++i)
 {
   c = (char) DecodeTable[(unsigned char)data[i]];
   ++i;
   c1 = (char) DecodeTable[(unsigned char)data[i]];
   c = (c << 2) | ((c1 >> 4) & 0x3);
   ret.append(1, c);
   if (++i < len)
   {
       c = data[i];
       if (fillchar == c)
           break;
  
       c = (char) DecodeTable[(unsigned char)data[i]];
       c1 = ((c1 << 4) & 0xf0) | ((c >> 2) & 0xf);
       ret.append(1, c1);
   }
  
   if (++i < len)
   {
       c1 = data[i];
       if (fillchar == c1)
           break;
  
       c1 = (char) DecodeTable[(unsigned char)data[i]];
       c = ((c << 6) & 0xc0) | c1;
       ret.append(1, c);
   }
 }
 
 return(ret);
}