Major plugin refactor and cleanup.

Switched to POCO library for unified platform/library interface.
Deprecated the external module API. It was creating more problems than solving.
Removed most built-in libraries in favor of system libraries for easier maintenance.
Cleaned and secured code with help from static analyzers.

vendor/POCO/Net/src/QuotedPrintableEncoder.cpp

@@ -0,0 +1,150 @@
+//
+// QuotedPrintableEncoder.cpp
+//
+// Library: Net
+// Package: Messages
+// Module:  QuotedPrintableEncoder
+//
+// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/Net/QuotedPrintableEncoder.h"
+#include "Poco/NumberFormatter.h"
+
+
+using Poco::UnbufferedStreamBuf;
+using Poco::NumberFormatter;
+
+
+namespace Poco {
+namespace Net {
+
+
+QuotedPrintableEncoderBuf::QuotedPrintableEncoderBuf(std::ostream& ostr): 
+	_pending(-1),
+	_lineLength(0),
+	_ostr(ostr)
+{
+}
+
+
+QuotedPrintableEncoderBuf::~QuotedPrintableEncoderBuf()
+{
+	try
+	{
+		close();
+	}
+	catch (...)
+	{
+	}
+}
+
+
+int QuotedPrintableEncoderBuf::writeToDevice(char c)
+{
+	if (_pending != -1)
+	{
+		if (_pending == '\r' && c == '\n')
+			writeRaw((char) _pending);
+		else if (c == '\r' || c == '\n')
+			writeEncoded((char) _pending);
+		else
+			writeRaw((char) _pending);
+		_pending = -1;
+	}
+	if (c == '\t' || c == ' ')
+	{
+		_pending = charToInt(c);
+		return _pending;
+	}
+	else if (c == '\r' || c == '\n' || (c > 32 && c < 127 && c != '='))
+	{
+		writeRaw(c);
+	}
+	else
+	{
+		writeEncoded(c);
+	}
+	return charToInt(c);
+}
+
+
+void QuotedPrintableEncoderBuf::writeEncoded(char c)
+{
+	if (_lineLength >= 73)
+	{
+		_ostr << "=\r\n";
+		_lineLength = 3;
+	}
+	else _lineLength += 3;
+	_ostr << '=' << NumberFormatter::formatHex((unsigned) charToInt(c), 2);
+}
+
+
+void QuotedPrintableEncoderBuf::writeRaw(char c)
+{
+	if (c == '\r' || c == '\n')
+	{
+		_ostr.put(c);
+		_lineLength = 0;
+	}
+	else if (_lineLength < 75)
+	{
+		_ostr.put(c);
+		++_lineLength;
+	}
+	else
+	{
+		_ostr << "=\r\n" << c;
+		_lineLength = 1;
+	}
+}
+
+
+int QuotedPrintableEncoderBuf::close()
+{
+	sync();
+	return _ostr ? 0 : -1;
+}
+
+
+QuotedPrintableEncoderIOS::QuotedPrintableEncoderIOS(std::ostream& ostr): _buf(ostr)
+{
+	poco_ios_init(&_buf);
+}
+
+
+QuotedPrintableEncoderIOS::~QuotedPrintableEncoderIOS()
+{
+}
+
+
+int QuotedPrintableEncoderIOS::close()
+{
+	return _buf.close();
+}
+
+
+QuotedPrintableEncoderBuf* QuotedPrintableEncoderIOS::rdbuf()
+{
+	return &_buf;
+}
+
+
+QuotedPrintableEncoder::QuotedPrintableEncoder(std::ostream& ostr): 
+	QuotedPrintableEncoderIOS(ostr), 
+	std::ostream(&_buf)
+{
+}
+
+
+QuotedPrintableEncoder::~QuotedPrintableEncoder()
+{
+}
+
+
+} } // namespace Poco::Net