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/Foundation/include/Poco/TextEncoding.h

@@ -0,0 +1,185 @@
+//
+// TextEncoding.h
+//
+// Library: Foundation
+// Package: Text
+// Module:  TextEncoding
+//
+// Definition of the abstract TextEncoding class.
+//
+// Copyright (c) 2004-2007, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_TextEncoding_INCLUDED
+#define Foundation_TextEncoding_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/SharedPtr.h"
+
+
+namespace Poco {
+
+
+class TextEncodingManager;
+
+
+class Foundation_API TextEncoding
+	/// An abstract base class for implementing text encodings
+	/// like UTF-8 or ISO 8859-1.
+	///
+	/// Subclasses must override the canonicalName(), isA(),
+	/// characterMap() and convert() methods and need to be
+	/// thread safe and stateless.
+	///
+	/// TextEncoding also provides static member functions
+	/// for managing mappings from encoding names to
+	/// TextEncoding objects.
+{
+public:
+	using Ptr = SharedPtr<TextEncoding>;
+
+	enum
+	{
+		MAX_SEQUENCE_LENGTH = 4 /// The maximum character byte sequence length supported.
+	};
+
+	typedef int CharacterMap[256];
+		/// The map[b] member gives information about byte sequences
+		/// whose first byte is b.
+		/// If map[b] is c where c is >= 0, then b by itself encodes the Unicode scalar value c.
+		/// If map[b] is -1, then the byte sequence is malformed.
+		/// If map[b] is -n, where n >= 2, then b is the first byte of an n-byte
+		/// sequence that encodes a single Unicode scalar value. Byte sequences up
+		/// to 4 bytes in length are supported.
+
+	virtual ~TextEncoding();
+		/// Destroys the encoding.
+
+	virtual const char* canonicalName() const = 0;
+		/// Returns the canonical name of this encoding,
+		/// e.g. "ISO-8859-1". Encoding name comparisons are case
+		/// insensitive.
+
+	virtual bool isA(const std::string& encodingName) const = 0;
+		/// Returns true if the given name is one of the names of this encoding.
+		/// For example, the "ISO-8859-1" encoding is also known as "Latin-1".
+		///
+		/// Encoding name comparisons are case insensitive.
+
+	virtual const CharacterMap& characterMap() const = 0;
+		/// Returns the CharacterMap for the encoding.
+		/// The CharacterMap should be kept in a static member. As
+		/// characterMap() can be called frequently, it should be
+		/// implemented in such a way that it just returns a static
+		/// map. If the map is built at runtime, this should be
+		/// done in the constructor.
+
+	virtual int convert(const unsigned char* bytes) const;
+		/// The convert function is used to convert multibyte sequences;
+		/// bytes will point to a byte sequence of n bytes where
+		/// sequenceLength(bytes, length) == -n, with length >= n.
+		///
+		/// The convert function must return the Unicode scalar value
+		/// represented by this byte sequence or -1 if the byte sequence is malformed.
+		///
+		/// The default implementation returns (int) bytes[0].
+
+	virtual	int queryConvert(const unsigned char* bytes, int length) const;
+		/// The queryConvert function is used to convert single byte characters
+		/// or multibyte sequences;
+		/// bytes will point to a byte sequence of length bytes.
+		///
+		/// The queryConvert function must return the Unicode scalar value
+		/// represented by this byte sequence or -1 if the byte sequence is malformed
+		/// or -n where n is number of bytes requested for the sequence, if length is
+		/// shorter than the sequence.
+		/// The length of the sequence might not be determined by the first byte,
+		/// in which case the conversion becomes an iterative process:
+		/// First call with length == 1 might return -2,
+		/// Then a second call with length == 2 might return -4
+		/// Eventually, the third call with length == 4 should return either a
+		/// Unicode scalar value, or -1 if the byte sequence is malformed.
+		///
+		/// The default implementation returns (int) bytes[0].
+
+	virtual int sequenceLength(const unsigned char* bytes, int length) const;
+		/// The sequenceLength function is used to get the lenth of the sequence pointed
+		/// by bytes. The length parameter should be greater or equal to the length of
+		/// the sequence.
+		///
+		/// The sequenceLength function must return the length of the sequence
+		/// represented by this byte sequence or a negative value -n if length is
+		/// shorter than the sequence, where n is the number of byte requested
+		/// to determine the length of the sequence.
+		/// The length of the sequence might not be determined by the first byte,
+		/// in which case the conversion becomes an iterative process as long as the
+		/// result is negative:
+		/// First call with length == 1 might return -2,
+		/// Then a second call with length == 2 might return -4
+		/// Eventually, the third call with length == 4 should return 4.
+		/// The default implementation returns 1.
+
+	virtual int convert(int ch, unsigned char* bytes, int length) const;
+		/// Transform the Unicode character ch into the encoding's
+		/// byte sequence. The method returns the number of bytes
+		/// used. The method must not use more than length characters.
+		/// Bytes and length can also be null - in this case only the number
+		/// of bytes required to represent ch is returned.
+		/// If the character cannot be converted, 0 is returned and
+		/// the byte sequence remains unchanged.
+		/// The default implementation simply returns 0.
+
+	static TextEncoding& byName(const std::string& encodingName);
+		/// Returns the TextEncoding object for the given encoding name.
+		///
+		/// Throws a NotFoundException if the encoding with given name is not available.
+
+	static TextEncoding::Ptr find(const std::string& encodingName);
+		/// Returns a pointer to the TextEncoding object for the given encodingName,
+		/// or NULL if no such TextEncoding object exists.
+
+	static void add(TextEncoding::Ptr encoding);
+		/// Adds the given TextEncoding to the table of text encodings,
+		/// under the encoding's canonical name.
+		///
+		/// If an encoding with the given name is already registered,
+		/// it is replaced.
+
+	static void add(TextEncoding::Ptr encoding, const std::string& name);
+		/// Adds the given TextEncoding to the table of text encodings,
+		/// under the given name.
+		///
+		/// If an encoding with the given name is already registered,
+		/// it is replaced.
+
+	static void remove(const std::string& encodingName);
+		/// Removes the encoding with the given name from the table
+		/// of text encodings.
+
+	static TextEncoding::Ptr global(TextEncoding::Ptr encoding);
+		/// Sets global TextEncoding object.
+		///
+		/// This function sets the global encoding to the argument and returns a
+		/// reference of the previous global encoding.
+
+	static TextEncoding& global();
+		/// Return the current global TextEncoding object
+
+	static const std::string GLOBAL;
+		/// Name of the global TextEncoding, which is the empty string.
+
+protected:
+	static TextEncodingManager& manager();
+		/// Returns the TextEncodingManager.
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_TextEncoding_INCLUDED