src/lib_json/json_tool.h

// Copyright 2007-2010 Baptiste Lepilleur
// Distributed under MIT license, or public domain if desired and
// recognized in your jurisdiction.
// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE

#ifndef LIB_JSONCPP_JSON_TOOL_H_INCLUDED
# define LIB_JSONCPP_JSON_TOOL_H_INCLUDED

/* This header provides common string manipulation support, such as UTF-8,
 * portable conversion from/to string...
 *
 * It is an internal header that must not be exposed.
 */

namespace Json {

/// Converts a unicode code-point to UTF-8.
static inline std::string 
codePointToUTF8(unsigned int cp)
{
   std::string result;
   
   // based on description from http://en.wikipedia.org/wiki/UTF-8

   if (cp <= 0x7f) 
   {
      result.resize(1);
      result[0] = static_cast<char>(cp);
   } 
   else if (cp <= 0x7FF) 
   {
      result.resize(2);
      result[1] = static_cast<char>(0x80 | (0x3f & cp));
      result[0] = static_cast<char>(0xC0 | (0x1f & (cp >> 6)));
   } 
   else if (cp <= 0xFFFF) 
   {
      result.resize(3);
      result[2] = static_cast<char>(0x80 | (0x3f & cp));
      result[1] = 0x80 | static_cast<char>((0x3f & (cp >> 6)));
      result[0] = 0xE0 | static_cast<char>((0xf & (cp >> 12)));
   }
   else if (cp <= 0x10FFFF) 
   {
      result.resize(4);
      result[3] = static_cast<char>(0x80 | (0x3f & cp));
      result[2] = static_cast<char>(0x80 | (0x3f & (cp >> 6)));
      result[1] = static_cast<char>(0x80 | (0x3f & (cp >> 12)));
      result[0] = static_cast<char>(0xF0 | (0x7 & (cp >> 18)));
   }

   return result;
}


/// Returns true if ch is a control character (in range [0,32[).
static inline bool 
isControlCharacter(char ch)
{
   return ch > 0 && ch <= 0x1F;
}


enum { 
   /// Constant that specify the size of the buffer that must be passed to uintToString.
   uintToStringBufferSize = 3*sizeof(LargestUInt)+1 
};

// Defines a char buffer for use with uintToString().
typedef char UIntToStringBuffer[uintToStringBufferSize];


/** Converts an unsigned integer to string.
 * @param value Unsigned interger to convert to string
 * @param current Input/Output string buffer. 
 *        Must have at least uintToStringBufferSize chars free.
 */
static inline void 
uintToString( LargestUInt value, 
              char *&current )
{
   *--current = 0;
   do
   {
      *--current = char(value % 10) + '0';
      value /= 10;
   }
   while ( value != 0 );
}

} // namespace Json {

#endif // LIB_JSONCPP_JSON_TOOL_H_INCLUDED