#pragma once

// Copyright Digital Mars 2003 - 2009.
// Authors: Walter Bright, Sean Kelly

// Boost Software License - Version 1.0 - August 17th, 2003

// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:

// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.

// 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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

#include <boost/config.hpp>
#include <stdexcept>

/*******************************
 * Test if c is a valid UTF-32 character.
 *
 * \uFFFE and \uFFFF are considered valid by this function,
 * as they are permitted for internal use by an application,
 * but they are not allowed for interchange by the Unicode standard.
 *
 * Returns: true if it is, false if not.
 */

inline bool isValidChar32(char32_t c) BOOST_NOEXCEPT
{
  /* Note: FFFE and FFFF are specifically permitted by the
   * Unicode standard for application internal use, but are not
   * allowed for interchange.
   * (thanks to Arcane Jill)
   */

  return c < 0xD800 ||
    (c > 0xDFFF && c <= 0x10FFFF /*&& c != 0xFFFE && c != 0xFFFF*/);
}

/***************
 * Decodes and returns character starting at s[idx]. idx is advanced past the
 * decoded character. If the character is not well formed, an exception is
 * thrown and idx remains unchanged.
 */

char32_t decodeUtf8(const char* s, size_t len, size_t& idx);