Base64.cpp

#include "Base64.h"

// Digits...
static char Base64Digits[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

BOOL CBase64::m_Init    = FALSE;
char CBase64::m_DecodeTable[256];

#ifndef PAGESIZE
#define PAGESIZE          4096
#endif

#ifndef ROUNDTOPAGE
#define ROUNDTOPAGE(a)      (((a/4096)+1)*4096)
#endif


CBase64::CBase64()
: m_pDBuffer(NULL),
m_pEBuffer(NULL),
m_nDBufLen(0),
m_nEBufLen(0)
{
  
}

CBase64::~CBase64()
{
  if(m_pDBuffer != NULL)
    delete [] m_pDBuffer;
  
  if(m_pEBuffer != NULL)
    delete [] m_pEBuffer;
}

const char* CBase64::DecodedMessage() const 
{ 
  return (const char*) m_pDBuffer;
}

const char* CBase64::EncodedMessage() const
{ 
  return (const char*) m_pEBuffer;
}

void CBase64::AllocEncode(unsigned long nSize)
{
  if(m_nEBufLen < nSize)
  {
    if(m_pEBuffer != NULL)
      delete [] m_pEBuffer;
    
    m_nEBufLen = ROUNDTOPAGE(nSize);
    m_pEBuffer = new unsigned char[m_nEBufLen];
  }
  
  ::ZeroMemory(m_pEBuffer, m_nEBufLen);
  m_nEDataLen = 0;
}

void CBase64::AllocDecode(unsigned long nSize)
{
  if(m_nDBufLen < nSize)
  {
    if(m_pDBuffer != NULL)
      delete [] m_pDBuffer;
    
    m_nDBufLen = ROUNDTOPAGE(nSize);
    m_pDBuffer = new unsigned char[m_nDBufLen];
  }
  
  ::ZeroMemory(m_pDBuffer, m_nDBufLen);
  m_nDDataLen = 0;
}

void CBase64::SetEncodeBuffer(const unsigned char* pBuffer, unsigned long nBufLen)
{
  unsigned long i = 0;
  
  AllocEncode(nBufLen);
  while(i < nBufLen)
  {
    if(!_IsBadMimeChar(pBuffer[i]))
    {
      m_pEBuffer[m_nEDataLen] = pBuffer[i];
      m_nEDataLen++;
    }
    
    i++;
  }
}

void CBase64::SetDecodeBuffer(const unsigned char* pBuffer, unsigned long nBufLen)
{
  AllocDecode(nBufLen);
  ::CopyMemory(m_pDBuffer, pBuffer, nBufLen);
  m_nDDataLen = nBufLen;
}

void CBase64::Encode(const unsigned char* pBuffer, unsigned long nBufLen)
{
  SetDecodeBuffer(pBuffer, nBufLen);
  AllocEncode(nBufLen * 2);
  
  TempBucket      Raw;
  unsigned long         nIndex  = 0;
  
  while((nIndex + 3) <= nBufLen)
  {
    Raw.Clear();
    ::CopyMemory(&Raw, m_pDBuffer + nIndex, 3);
    Raw.nSize = 3;
    _EncodeToBuffer(Raw, m_pEBuffer + m_nEDataLen);
    nIndex    += 3;
    m_nEDataLen += 4;
  }
  
  if(nBufLen > nIndex)
  {
    Raw.Clear();
    Raw.nSize = (unsigned char) (nBufLen - nIndex);
    ::CopyMemory(&Raw, m_pDBuffer + nIndex, nBufLen - nIndex);
    _EncodeToBuffer(Raw, m_pEBuffer + m_nEDataLen);
    m_nEDataLen += 4;
  }
}

void CBase64::Encode(const char* szMessage)
{
  if(szMessage != NULL)
    CBase64::Encode((const unsigned char*)szMessage, lstrlenA(szMessage));
}

void CBase64::Decode(const unsigned char* pBuffer, unsigned long dwBufLen)
{
  if(!CBase64::m_Init)
    _Init();
  
  SetEncodeBuffer(pBuffer, dwBufLen);
  
  AllocDecode(dwBufLen);
  
  TempBucket      Raw;
  
  unsigned long   nIndex = 0;
  
  while((nIndex + 4) <= m_nEDataLen)
  {
    Raw.Clear();
    Raw.nData[0] = CBase64::m_DecodeTable[m_pEBuffer[nIndex]];
    Raw.nData[1] = CBase64::m_DecodeTable[m_pEBuffer[nIndex + 1]];
    Raw.nData[2] = CBase64::m_DecodeTable[m_pEBuffer[nIndex + 2]];
    Raw.nData[3] = CBase64::m_DecodeTable[m_pEBuffer[nIndex + 3]];
    
    if(Raw.nData[2] == 255)
      Raw.nData[2] = 0;
    if(Raw.nData[3] == 255)
      Raw.nData[3] = 0;
    
    Raw.nSize = 4;
    _DecodeToBuffer(Raw, m_pDBuffer + m_nDDataLen);
    nIndex += 4;
    m_nDDataLen += 3;
  }
  
  // If nIndex < m_nEDataLen, then we got a decode message without padding.
  // We may want to throw some kind of warning here, but we are still required
  // to handle the decoding as if it was properly padded.
  if(nIndex < m_nEDataLen)
  {
    Raw.Clear();
    for(unsigned long i = nIndex; i < m_nEDataLen; i++)
    {
      Raw.nData[i - nIndex] = CBase64::m_DecodeTable[m_pEBuffer[i]];
      Raw.nSize++;
      if(Raw.nData[i - nIndex] == 255)
        Raw.nData[i - nIndex] = 0;
    }
    
    _DecodeToBuffer(Raw, m_pDBuffer + m_nDDataLen);
    m_nDDataLen += (m_nEDataLen - nIndex);
  }
}

void CBase64::Decode(const char* szMessage)
{
  if(szMessage != NULL)
    CBase64::Decode((const unsigned char*)szMessage, lstrlenA(szMessage));
}

unsigned long CBase64::_DecodeToBuffer(const TempBucket &Decode, unsigned char* pBuffer)
{
  TempBucket  Data;
  unsigned long     nCount = 0;
  
  _DecodeRaw(Data, Decode);
  
  for(int i = 0; i < 3; i++)
  {
    pBuffer[i] = Data.nData[i];
    if(pBuffer[i] != 255)
      nCount++;
  }
  
  return nCount;
}


void CBase64::_EncodeToBuffer(const TempBucket &Decode, unsigned char* pBuffer)
{
  TempBucket  Data;
  
  _EncodeRaw(Data, Decode);
  
  for(int i = 0; i < 4; i++)
    pBuffer[i] = Base64Digits[Data.nData[i]];
  
  switch(Decode.nSize)
  {
  case 1:
    pBuffer[2] = '=';
  case 2:
    pBuffer[3] = '=';
  }
}

void CBase64::_DecodeRaw(TempBucket &Data, const TempBucket &Decode)
{
  unsigned char    nTemp;
  
  Data.nData[0] = Decode.nData[0];
  Data.nData[0] <<= 2;
  
  nTemp = Decode.nData[1];
  nTemp >>= 4;
  nTemp &= 0x03;
  Data.nData[0] |= nTemp;
  
  Data.nData[1] = Decode.nData[1];
  Data.nData[1] <<= 4;
  
  nTemp = Decode.nData[2];
  nTemp >>= 2;
  nTemp &= 0x0F;
  Data.nData[1] |= nTemp;
  
  Data.nData[2] = Decode.nData[2];
  Data.nData[2] <<= 6;
  nTemp = Decode.nData[3];
  nTemp &= 0x3F;
  Data.nData[2] |= nTemp;
}

void CBase64::_EncodeRaw(TempBucket &Data, const TempBucket &Decode)
{
  unsigned char    nTemp;
  
  Data.nData[0] = Decode.nData[0];
  Data.nData[0] >>= 2;
  
  Data.nData[1] = Decode.nData[0];
  Data.nData[1] <<= 4;
  nTemp = Decode.nData[1];
  nTemp >>= 4;
  Data.nData[1] |= nTemp;
  Data.nData[1] &= 0x3F;
  
  Data.nData[2] = Decode.nData[1];
  Data.nData[2] <<= 2;
  
  nTemp = Decode.nData[2];
  nTemp >>= 6;
  
  Data.nData[2] |= nTemp;
  Data.nData[2] &= 0x3F;
  
  Data.nData[3] = Decode.nData[2];
  Data.nData[3] &= 0x3F;
}

BOOL CBase64::_IsBadMimeChar(unsigned char nData)
{
  switch(nData)
  {
  case '\r': case '\n': case '\t': case ' ' :
  case '\b': case '\a': case '\f': case '\v':
    return TRUE;
  default:
    return FALSE;
  }
}

void CBase64::_Init()
{  // Initialize Decoding table.
  
  int i;
  
  for(i = 0; i < 256; i++)
    CBase64::m_DecodeTable[i] = -2;
  
  for(i = 0; i < 64; i++)
  {
    CBase64::m_DecodeTable[Base64Digits[i]]     = (CHAR)i;
    CBase64::m_DecodeTable[Base64Digits[i]|0x80]  = (CHAR)i;
  }
  
  CBase64::m_DecodeTable['=']       = -1;
  CBase64::m_DecodeTable['='|0x80]    = -1;
  
  CBase64::m_Init = TRUE;
}