En/Decode MIME-Content with MimeSniffer

// QuotedPrinted.cpp: implementation of the CQuotedPrintable class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "QuotedPrinted.h"
#include "ISSHelper.h"

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CQuotedPrintable::CQuotedPrintable()
{
	m_bInline = FALSE;
}

CQuotedPrintable::~CQuotedPrintable()
{

}

int CQuotedPrintable::Decode( LPCBYTE szDecoding, LPTSTR szOutput, DWORD len )
{
	if (!m_bInline)
		return CMIMECode::Decode( szDecoding, szOutput, len );

	if (len == MAXDWORD)
	   len = strlen((const char*)szDecoding);

	DWORD	nOut = 0;

	for (DWORD lauf = 0; lauf < len; lauf++)
	{
	   if (m_strInline.length() > 0)
	   {
		  if (strncmp((const char*)szDecoding+lauf, m_strInline.c_str(), m_strInline.length()) == 0)
		  {
		     lauf += m_strInline.length()-1;
			 continue;
		  }
	   }
	   if (szDecoding[lauf] == '=')
	   {
		  if (lauf+2 < len)
		  {
		     if		 (szDecoding[lauf+1] == '\r' && szDecoding[lauf+2] == '\n')
			 {
			 // Do nothing
			 }
			 else
			 {
				if (szOutput != NULL)
					szOutput[nOut++] = (HexToNum(szDecoding[lauf+1]) << 4) + HexToNum(szDecoding[lauf+2]);
				else
				   nOut++;
			 }
			 lauf += 2;
		  }
	   }
	   else
	   {
	      if (szDecoding[lauf] == '_')
		  {
			 if (szOutput != NULL)
				szOutput[nOut++] = ' ';
			 else
				nOut++;
		  }
		  else
		  {
			 if (szOutput != NULL)
				szOutput[nOut++] = szDecoding[lauf];
			 else
				nOut++;
		  }
	   }
	}
	return nOut;
}

void CQuotedPrintable::Encode( LPCBYTE szEncoding, int nSize, string& strResult)
{
	DWORD		nBreak = 75;

	if (!m_bInline)
	{
		CMIMECode::Encode( szEncoding, nSize, strResult );
		return;
	}

	char   buf[16];

	strResult	= _T("=?iso-8859-1?Q?");

	for (int lauf = 0; lauf < nSize; lauf++)
	{
	   buf[0] = szEncoding[lauf];
	   buf[1] = 0;

	   if (buf[0] == ' ')
		  buf[0] = '_';
	   else if (	buf[0] > 127 
				||	buf[0] == '='
				||	!isalnum(buf[0])
				)
	   {
		  sprintf(buf, "=%02X", (unsigned int)szEncoding[lauf]);
	   }
	// special Handling
	   if (nBreak-strResult.length() < 2)
	   {
		  strResult += "?=\r\n\t=?iso-8859-1?Q?";
		  nBreak	+= 75;
	   }
	   strResult += buf;
	}
	strResult	+= _T("?=");
}

void CQuotedPrintable::Decode(LPSTREAM pSource, LPSTREAM pDest)
{
	BYTE	c;
	BYTE	c1;
	DWORD	dwRead;

	do
	{
		pSource->Read(&c, 1, &dwRead);

		if (dwRead != 1)
			break;

		if (c == '=')
		{
			pSource->Read(&c, 1, &dwRead);

			if (dwRead != 1)
				break;

			pSource->Read(&c1, 1, &dwRead);

			if (dwRead != 1)
				break;

			if (c == '\r' && c1 == '\n')
			{
				// Do nothing
			}
			else
			{
				c = (HexToNum(c) << 4) + HexToNum(c1);
				
				pDest->Write(&c, 1, NULL);
			}
		}
		else
		{
			pDest->Write(&c, 1, NULL);
		}
	}
	while(true);
}

void CQuotedPrintable::Encode(LPSTREAM pSource, LPSTREAM pDest)
{
	BYTE		c;
	DWORD		dwRead;
	char		buf[128];
	DWORD		nBreak = 75;
	int			nState = 0;
	BYTE		nLast;
	DWORD		dwWritten = 0;
	DWORD		dwWrittenWithoutLineFeed = 0;

	memset(buf, 0, sizeof(buf));

	do
	{
		pSource->Read(&c, 1, &dwRead);

		if (dwRead != 1)
		{
			if (strlen(buf) > 0)
			{
				pDest->Write(buf, strlen(buf), NULL);
				dwWritten += strlen(buf);
				nLast = buf[strlen(buf)-1];
			}
			break;
		}
		if (strlen(buf) > 40)
		{
			if (strstr(buf, "\n") != 0)
				dwWrittenWithoutLineFeed = 0;
			else
				dwWrittenWithoutLineFeed += 20;

			if (dwWrittenWithoutLineFeed > nBreak)
			{
				pDest->Write("=\r\n", 3, NULL);	
				dwWrittenWithoutLineFeed = 0;
			}

			pDest->Write(buf, 20, NULL);
			dwWritten += 20;

			memmove(buf, buf+20, sizeof(buf)-20);
		}
	   
		if (	    c < 9
				||  (c > 9  && c < 10)
				||  (c > 10 && c < 13)
				||  (c > 13 && c < 32)
				||  (c > 60 && c < 62)
				||  c > 126
		   )
		{
			sprintf(buf+strlen(buf), "=%02X", (unsigned int)c);
		}
		else
		{
			buf[strlen(buf)] = c;

			restate:

			switch(nState)
			{
				case 0:
				{
					if      (c == '\r')
					{
						nState = 1;
						continue;
					}
					else if (c == ' ')
					{
						nState = 10;
						continue;
					}
					else if (c == '\t')
					{
						nState = 20;
						continue;
					}
				}
				break;

				case 1:
				{
					if (c == '\n')
					{
						nState = 2;
						continue;
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 2:
				{
					if (c == '.')
					{
						nState = 3;
						continue;
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 3:
				{
					if (c == '\r')
					{
						nState = 4;
						continue;
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 4:
				{
					if (c == '\n')
					{
						sprintf(buf+strlen(buf)-3, "=2E\r\n");
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 10:
				{
					if (c == '\r')
					{
						nState = 11;
						continue;
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 11:
				{
					if (c == '\n')
					{
						sprintf(buf+strlen(buf)-3, "=20\r\n");
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 20:
				{
					if (c == '\r')
					{
						nState = 21;
						continue;
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				case 21:
				{
					if (c == '\n')
					{
						sprintf(buf+strlen(buf)-3, "=09\r\n");
					}
					else
					{
						nState = 0;
						goto restate;
					}
				}
				break;

				default:
				{
					ATLASSERT(FALSE);
				}
				break;
			}
		}
		if (strlen(buf) > 0)
		{
			if (strstr(buf, "\n") != 0)
				dwWrittenWithoutLineFeed = 0;
			else
				dwWrittenWithoutLineFeed += strlen(buf);

			if (dwWrittenWithoutLineFeed > nBreak)
			{
				pDest->Write("=\r\n", 3, NULL);	
				dwWrittenWithoutLineFeed = 0;
			}

			pDest->Write(buf, strlen(buf), NULL);
			dwWritten += strlen(buf);
			nLast = buf[strlen(buf)-1];
		}
		memset(buf, 0, sizeof(buf));
		nState = 0;
	}
	while(true);

	if (dwWritten > 0 && nLast != 10)
		pDest->Write("\r\n", 2, NULL);
}