area51/Support/SMTP/Base64Coder.cpp
Andrew Sampson 431f72b93a source
2021-08-27 19:22:41 -07:00

336 lines
7.3 KiB
C++

/*
Module : Base64Coder.CPP
Purpose: Implementation for the Base64 encoder / decoder class
Created: PJN / 20-06-2000
History: None
Copyright (c) 1998 - 2004 by PJ Naughter.
All rights reserved.
*/
//////////////// Includes ////////////////////////////////////////////
#include "stdafx.h"
#include "Base64Coder.h"
//////////////// Macros / Locals /////////////////////////////////////
static char Base64Digits[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
BOOL CBase64Coder::m_Init = FALSE;
char CBase64Coder::m_DecodeTable[256];
#ifndef PAGESIZE
#define PAGESIZE 4096
#endif
#ifndef ROUNDTOPAGE
#define ROUNDTOPAGE(a) (((a/4096)+1)*4096)
#endif
////////////////// Implementation ////////////////////////////////////
CBase64Coder::CBase64Coder() : m_pDBuffer(NULL), m_pEBuffer(NULL),
m_nDBufLen(0), m_nEBufLen(0)
{
}
CBase64Coder::~CBase64Coder()
{
if (m_pDBuffer != NULL)
{
delete [] m_pDBuffer;
m_pDBuffer = NULL;
}
if (m_pEBuffer != NULL)
{
delete [] m_pEBuffer;
m_pEBuffer = NULL;
}
}
LPSTR CBase64Coder::DecodedMessage() const
{
return (LPSTR) m_pDBuffer;
}
LPSTR CBase64Coder::EncodedMessage() const
{
return (LPSTR) m_pEBuffer;
}
LONG CBase64Coder::DecodedMessageSize() const
{
return m_nDDataLen;
}
LONG CBase64Coder::EncodedMessageSize() const
{
return m_nEDataLen;
}
void CBase64Coder::AllocEncode(DWORD nSize)
{
if (m_nEBufLen < nSize)
{
if (m_pEBuffer != NULL)
delete [] m_pEBuffer;
m_nEBufLen = ROUNDTOPAGE(nSize);
m_pEBuffer = new BYTE[m_nEBufLen];
}
::ZeroMemory(m_pEBuffer, m_nEBufLen);
m_nEDataLen = 0;
}
void CBase64Coder::AllocDecode(DWORD nSize)
{
if (m_nDBufLen < nSize)
{
if (m_pDBuffer != NULL)
delete [] m_pDBuffer;
m_nDBufLen = ROUNDTOPAGE(nSize);
m_pDBuffer = new BYTE[m_nDBufLen];
}
::ZeroMemory(m_pDBuffer, m_nDBufLen);
m_nDDataLen = 0;
}
void CBase64Coder::SetEncodeBuffer(const PBYTE pBuffer, DWORD nBufLen)
{
DWORD i = 0;
AllocEncode(nBufLen);
while(i < nBufLen)
{
if (!_IsBadMimeChar(pBuffer[i]))
{
m_pEBuffer[m_nEDataLen] = pBuffer[i];
m_nEDataLen++;
}
i++;
}
}
void CBase64Coder::SetDecodeBuffer(const PBYTE pBuffer, DWORD nBufLen)
{
AllocDecode(nBufLen);
::CopyMemory(m_pDBuffer, pBuffer, nBufLen);
m_nDDataLen = nBufLen;
}
void CBase64Coder::Encode(const PBYTE pBuffer, DWORD nBufLen)
{
SetDecodeBuffer(pBuffer, nBufLen);
AllocEncode(nBufLen * 2);
TempBucket Raw;
DWORD 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 = (BYTE) (nBufLen - nIndex);
::CopyMemory(&Raw, m_pDBuffer + nIndex, nBufLen - nIndex);
_EncodeToBuffer(Raw, m_pEBuffer + m_nEDataLen);
m_nEDataLen += 4;
}
}
void CBase64Coder::Encode(LPCSTR szMessage)
{
if (szMessage != NULL)
Encode((const PBYTE)szMessage, (int)strlen(szMessage));
}
void CBase64Coder::Decode(const PBYTE pBuffer, DWORD dwBufLen)
{
if (!CBase64Coder::m_Init)
_Init();
SetEncodeBuffer(pBuffer, dwBufLen);
AllocDecode(dwBufLen);
TempBucket Raw;
DWORD nIndex = 0;
while((nIndex + 4) <= m_nEDataLen)
{
Raw.Clear();
Raw.nData[0] = CBase64Coder::m_DecodeTable[m_pEBuffer[nIndex]];
Raw.nData[1] = CBase64Coder::m_DecodeTable[m_pEBuffer[nIndex + 1]];
Raw.nData[2] = CBase64Coder::m_DecodeTable[m_pEBuffer[nIndex + 2]];
Raw.nData[3] = CBase64Coder::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 (DWORD i=nIndex; i<m_nEDataLen; i++)
{
Raw.nData[i - nIndex] = CBase64Coder::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 CBase64Coder::Decode(LPCSTR szMessage)
{
if (szMessage != NULL)
Decode((const PBYTE)szMessage, (int)strlen(szMessage));
}
DWORD CBase64Coder::_DecodeToBuffer(const TempBucket &Decode, PBYTE pBuffer)
{
TempBucket Data;
DWORD 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 CBase64Coder::_EncodeToBuffer(const TempBucket &Decode, PBYTE 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 CBase64Coder::_DecodeRaw(TempBucket &Data, const TempBucket &Decode)
{
BYTE 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 CBase64Coder::_EncodeRaw(TempBucket &Data, const TempBucket &Decode)
{
BYTE 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 CBase64Coder::_IsBadMimeChar(BYTE nData)
{
switch(nData)
{
case '\r': case '\n': case '\t': case ' ' :
case '\b': case '\a': case '\f': case '\v':
return TRUE;
default:
return FALSE;
}
}
void CBase64Coder::_Init()
{
// Initialize Decoding table.
int i;
for (i=0; i<256; i++)
CBase64Coder::m_DecodeTable[i] = -2;
for (i=0; i<64; i++)
{
CBase64Coder::m_DecodeTable[Base64Digits[i]] = (char) i;
CBase64Coder::m_DecodeTable[Base64Digits[i]|0x80] = (char) i;
}
CBase64Coder::m_DecodeTable['='] = -1;
CBase64Coder::m_DecodeTable['='|0x80] = -1;
CBase64Coder::m_Init = TRUE;
}