CharactersWriter.hpp

/*
  Copyright (C) 2013 Przemek Mazurkiewicz (Przemek.Mazurkiewicz.2009@gmail.com)

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

#ifndef XML_CHARACTERS_WRITER_HPP__f66b9cdaf20734ef11086d0851a9c563
#define XML_CHARACTERS_WRITER_HPP__f66b9cdaf20734ef11086d0851a9c563

#include <string>

/**
	@file CharactersWriter.hpp
*/

namespace Xml
{
	namespace Encoding
	{
		/**
			@brief Class responsible for writing strings in the UTF-8 encoding.

			@sa Utf16Writer, Utf32Writer and Inspector.
		*/
		class Utf8Writer
		{
		public:
			/**
				@brief String type that is able to store the UTF-8 encoded string.
			*/
			typedef std::string StringType;

			/**
				@brief Inserts the Unicode character into the UTF-8 encoded string.

				@param[out] stringDestination String where the character should be inserted.
				@param codePoint Code point of the Unicode character to write.
			*/
			static void WriteCharacter(StringType& stringDestination, char32_t codePoint);
		};

		/**
			@brief Class responsible for writing strings in the UTF-16 encoding.

			@sa Utf8Writer, Utf32Writer and Inspector.
		*/
		class Utf16Writer
		{
		public:
			/**
				@brief String type that is able to store the UTF-16 encoded string.
			*/
			typedef std::u16string StringType;

			/**
				@brief Inserts the Unicode character into the UTF-16 encoded string.

				@param[out] stringDestination String where the character should be inserted.
				@param codePoint Code point of the Unicode character to write.
			*/
			static void WriteCharacter(StringType& stringDestination, char32_t codePoint);
		};

		/**
			@brief Class responsible for writing strings in the UTF-32 encoding.

			@sa Utf8Writer, Utf16Writer and Inspector.
		*/
		class Utf32Writer
		{
		public:
			/**
				@brief String type that is able to store the UTF-32 encoded string.
			*/
			typedef std::u32string StringType;

			/**
				@brief Inserts Unicode character into the UTF-32 encoded string.

				@param[out] stringDestination String where the character should be inserted.
				@param codePoint Code point of Unicode character to write.
			*/
			static void WriteCharacter(StringType& stringDestination, char32_t codePoint);
		};

		inline void Utf8Writer::WriteCharacter(
			StringType& stringDestination, char32_t codePoint)
		{
			if (codePoint <= 0x7F)
			{
				stringDestination.push_back(static_cast<StringType::value_type>(codePoint));
			}
			else if (codePoint <= 0x7FF)
			{
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint >> 6) | 0xC0));
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint & 0x3F) | 0x80));
			}
			else if (codePoint <= 0xFFFF)
			{
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint >> 12) | 0xE0));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 6) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint & 0x3F) | 0x80));
			}
			else if (codePoint <= 0x1FFFFF)
			{
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint >> 18) | 0xF0));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 12) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 6) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint & 0x3F) | 0x80));
			}
			// Invalid character. Put this anyway.
			else if (codePoint <= 0x3FFFFFF)
			{
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint >> 24) | 0xF8));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 18) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 12) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 6) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint & 0x3F) | 0x80));
			}
			else
			{
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint >> 30) | 0xFC));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 24) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 18) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 12) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					((codePoint >> 6) & 0x3F) | 0x80));
				stringDestination.push_back(static_cast<StringType::value_type>(
					(codePoint & 0x3F) | 0x80));
			}
		}

		inline void Utf16Writer::WriteCharacter(
			StringType& stringDestination, char32_t codePoint)
		{
			if ((codePoint <= 0xD7FF) || (codePoint >= 0xE000 && codePoint <= 0xFFFF))
			{
				stringDestination.push_back(static_cast<StringType::value_type>(codePoint));
			}
			else if (codePoint >= 0x10000 && codePoint <= 0x10FFFF)
			{
				// We have surrogate pair.
				codePoint -= 0x10000;
				char32_t surr = (codePoint >> 10) + 0xD800; // Lead surrogate.
				stringDestination.push_back(static_cast<StringType::value_type>(surr));
				surr = (codePoint & 0x3FF) + 0xDC00; // Trail surrogate.
				stringDestination.push_back(static_cast<StringType::value_type>(surr));
			}
		}

		inline void Utf32Writer::WriteCharacter(
			StringType& stringDestination, char32_t codePoint)
		{
			stringDestination.push_back(static_cast<StringType::value_type>(codePoint));
		}
	}
}

#endif