Rapidjson is an attempt to create the fastest json parser and generator.

- small but complete. supports both sax and dom style api. sax parser only a
few hundred lines of code.
- fast. in the order of magnitude of strlen(). optionally supports
sse2/sse4.2 for acceleration.
- self-contained. minimal dependency on standard libraries. no boost, not
even stl.
- compact. each json value is 16 or 20 bytes for 32 or 64-bit machines
respectively (excluding text string storage). with the custom memory
allocator, parser allocates memory compactly during parsing.
- full rfc7159 compliance. supports utf-8, utf-16 and utf-32.
- support both in-situ parsing (directly decode strings into the source json
text) and non-destructive parsing (decode strings into new buffers).
- parse number to int/unsigned/int64_t/uint64_t/double depending on input
- support custom memory allocation. also, the default memory pool allocator
can also be supplied with a user buffer (such as a buffer allocated on
user's heap or programme stack) to minimize allocation.