#include "MimeBase64.h"

// This is based heavily on http://base64.sourceforge.net/b64.c

/*
** Translation Table as described in RFC1113
*/
static const char cb64[]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/*
** encodeblock
**
** encode 3 8-bit binary bytes as 4 '6-bit' characters
*/
static void encodeblock(unsigned char const *in, std::string &out, int len)
{
  out += cb64[ in[0] >> 2 ];
  out += cb64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4) ];
  if (len <= 1)
    out += '=';
  else
    out += cb64[ ((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6) ];
  if (len <= 2)
    out += '=';
  else
    out += cb64[ in[2] & 0x3f ];
}

/*
** encode
**
** base64 encode a string adding padding and line breaks as per spec.
** the result is appended to the destination.
*/
void base64Encode(std::string const &source, std::string &destination)
{
  int blocksout = 0;
  // Use c_str(), not data(), to ensure that we have one extra byte on the
  // end.  encodeblock will make use of that extra byte and will assume it
  // is 0.
  unsigned const char *toEncode = (unsigned const char *)source.c_str();  
  for (int available = source.size(); 
       available > 0; 
       available -= 3, toEncode += 3) 
    {
      encodeblock(toEncode, destination, available);
      blocksout++;
      if ((blocksout >= 19) && (available > 0)) 
	{
	  if( blocksout ) 
	    {
	      destination += "\r\n";
	    }
	  blocksout = 0;
	}
    }
}

/*
** encode
**
** base64 encode a string adding padding and line breaks as per spec.
** the result is appended to the destination.
*/
std::string base64Encode(std::string const &source)
{
  std::string result;
  const int blocks = (source.size() + 2) / 3;
  const int lineBreaks = blocks / 19;  
  // This estimate might have room for one extra \r\n
  const int size = blocks * 4 + lineBreaks * 2;
  result.reserve(size);
  base64Encode(source, result);
  return result;
}

#ifdef __UNIT_TEST_

// g++ -Wall -ggdb -D__UNIT_TEST_ MimeBase64.C

#include <iostream>

void testOne(std::string input)
{ // This could be fed into PHP.
  std::cout<<"if (\""
	   <<input
	   <<"\" != base64_decode(\""
	   <<base64Encode(input)
	   <<"\")) echo \"error -- "
	   <<input
	   <<"\";"
	   <<std::endl;
}

int main(int, char **)
{
  testOne("");
  testOne("1");
  testOne("12");
  testOne("12");
  testOne("123");
  testOne("1234");
  testOne("12345");
  testOne("The quick brown fox jumps over the lazy dog.");
  testOne("The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog.");
  testOne("The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog.1");
  testOne("The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog.12");
  testOne("The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog.123");
}

#endif