RapidJSON is a JSON parser and generator for C++. It was inspired by 
RapidXml.

Features:
 - RapidJSON is small but complete. It supports both SAX and DOM 
   style API. The SAX parser is only a half thousand lines of code.

 - RapidJSON is fast. Its performance can be comparable to strlen().
   It also optionally supports SSE2/SSE4.2 for acceleration.

 - RapidJSON is self-contained and header-only. It does not depend on
   external libraries such as BOOST. It even does not depend on STL.

 - RapidJSON is memory-friendly. Each JSON value occupies exactly 16 
   bytes for most 32/64-bit machines (excluding text string). By 
   default it uses a fast memory allocator, and the parser allocates 
   memory compactly during parsing.

 - RapidJSON is Unicode-friendly. It supports UTF-8, UTF-16, UTF-32 
   (LE & BE), and their detection, validation and transcoding
   internally. For example, you can read a UTF-8 file and let RapidJSON 
   transcode the JSON strings into UTF-16 in the DOM. It also supports 
   surrogates and "\u0000" (null character).