vmime/src/utility/filteredStream.cpp

//
// VMime library (http://www.vmime.org)
// Copyright (C) 2002-2005 Vincent Richard <vincent@vincent-richard.net>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//

#include "vmime/utility/filteredStream.hpp"

#include <algorithm>


namespace vmime {
namespace utility {


// dotFilteredInputStream

dotFilteredInputStream::dotFilteredInputStream(inputStream& is)
	: m_stream(is)
{
}


inputStream& dotFilteredInputStream::getPreviousInputStream()
{
	return (m_stream);
}


const bool dotFilteredInputStream::eof() const
{
	return (m_stream.eof());
}


void dotFilteredInputStream::reset()
{
	m_previousChar2 = '\0';
	m_previousChar1 = '\0';

	m_stream.reset();
}


const stream::size_type dotFilteredInputStream::read(value_type* const data, const size_type count)
{
	const stream::size_type read = m_stream.read(data, count);

	const value_type* readPtr = data;
	value_type* writePtr = data;

	const value_type* end = data + read;

	stream::size_type written = 0;

	// Replace "\n.." with "\n."
	while (readPtr < end)
	{
		if (*readPtr == '.')
		{
			const value_type prevChar2 =
				(readPtr == data + 1 ? m_previousChar1 :
				 readPtr == data ? m_previousChar2 : *(readPtr - 2));
			const value_type prevChar1 =
				(readPtr == data ? m_previousChar1 : *(readPtr - 1));

			if (prevChar2 == '\n' && prevChar1 == '.')
			{
				// Ignore last dot
			}
			else
			{
				*writePtr = *readPtr;

				++writePtr;
				++written;
			}
		}
		else
		{
			*writePtr = *readPtr;

			++writePtr;
			++written;
		}

		++readPtr;
	}

	m_previousChar2 = (read >= 2 ? data[read - 2] : m_previousChar1);
	m_previousChar1 = (read >= 1 ? data[read - 1] : '\0');

	return (written);
}


const stream::size_type dotFilteredInputStream::skip(const size_type /* count */)
{
	// Skipping bytes is not supported
	return 0;
}


// dotFilteredOutputStream

dotFilteredOutputStream::dotFilteredOutputStream(outputStream& os)
	: m_stream(os)
{
}


outputStream& dotFilteredOutputStream::getNextOutputStream()
{
	return (m_stream);
}


void dotFilteredOutputStream::write
	(const value_type* const data, const size_type count)
{
	if (count == 0)
		return;

	const value_type* pos = data;
	const value_type* end = data + count;
	const value_type* start = data;

	// Replace "\n." with "\n.."
	while ((pos = std::find(pos, end, '.')) != end)
	{
		const value_type previousChar =
			(pos == data ? m_previousChar : *(pos - 1));

		if (previousChar == '\n')
		{
			m_stream.write(start, pos - data);
			m_stream.write("..", 2);

			start = pos + 1;
		}

		++pos;
	}

	m_stream.write(start, end - start);
	m_previousChar = data[count - 1];
}


// CRLFToLFFilteredOutputStream

CRLFToLFFilteredOutputStream::CRLFToLFFilteredOutputStream(outputStream& os)
	: m_stream(os)
{
}


outputStream& CRLFToLFFilteredOutputStream::getNextOutputStream()
{
	return (m_stream);
}


void CRLFToLFFilteredOutputStream::write
	(const value_type* const data, const size_type count)
{
	if (count == 0)
		return;

	const value_type* pos = data;
	const value_type* end = data + count;
	const value_type* start = data;

	// Warning: if the whole buffer finishes with '\r', this
	// last character will not be written back...
	// TODO: add a finalize() method?
	if (m_previousChar == '\r')
	{
		if (*pos != '\n')
		{
			m_stream.write("\r", 1); // write back \r
			m_previousChar = *pos;
		}
	}

	// Replace "\r\n" (CRLF) with "\n" (LF)
	while ((pos = std::find(pos, end, '\n')) != end)
	{
		const value_type previousChar =
			(pos == data ? m_previousChar : *(pos - 1));

		if (previousChar == '\r')
		{
			if (pos != data)
				m_stream.write(start, pos - 1 - data);  // do not write \r

			m_stream.write("\n", 1);

			start = pos + 1;
		}

		++pos;
	}

	if (data[count - 1] == '\r')
	{
		m_stream.write(start, end - start - 1);
		m_previousChar = '\r';
	}
	else
	{
		m_stream.write(start, end - start);
		m_previousChar = data[count - 1];
	}
}


} // utility
} // vmime