4.9 KiB
4.9 KiB
Features
General
- Cross-platform
- Compilers: Visual Studio, gcc, clang, etc.
- Architectures: x86, x64, ARM, etc.
- Operating systems: Windows, Mac OS X, Linux, iOS, Android, etc.
- Easy installation
- Header files only library. Just copy the headers to your project.
- Self-contained, minimal dependences
- No STL, BOOST, etc.
- Only included
<cstdio>
,<cstdlib>
,<cstring>
,<inttypes.h>
,<new>
,<stdint.h>
. - Without C++ exception, RTTI
- High performance
- Use template and inline functions to reduce function call overheads.
- Internal optimized Grisu2 and floating point parsing implementations.
- Optional SSE2/SSE4.2 support.
Standard compliance
- RapidJSON should be fully RFC4627/ECMA-404 compliance.
- Support JSON Pointer (RFC6901).
- Support JSON Schema Draft v4.
- Support Unicode surrogate.
- Support null character (
"\u0000"
) - For example,
["Hello\u0000World"]
can be parsed and handled gracefully. There is API for getting/setting lengths of string. - Support optional relaxed syntax.
- Single line (
// ...
) and multiple line (/* ... */
) comments (kParseCommentsFlag
). - Trailing commas at the end of objects and arrays
(
kParseTrailingCommasFlag
). NaN
,Inf
,Infinity
,-Inf
and-Infinity
asdouble
values (kParseNanAndInfFlag
)- NPM compliant.
Unicode
- Support UTF-8, UTF-16, UTF-32 encodings, including little endian and big endian.
- These encodings are used in input/output streams and in-memory representation.
- Support automatic detection of encodings in input stream.
- Support transcoding between encodings internally.
- For example, you can read a UTF-8 file and let RapidJSON transcode the JSON strings into UTF-16 in the DOM.
- Support encoding validation internally.
- For example, you can read a UTF-8 file, and let RapidJSON check whether all JSON strings are valid UTF-8 byte sequence.
- Support custom character types.
- By default the character types are
char
for UTF8,wchar_t
for UTF16,uint32_t
for UTF32. - Support custom encodings.
API styles
- SAX (Simple API for XML) style API
- Similar to SAX,
RapidJSON provides a event sequential access parser API
(
rapidjson::GenericReader
). It also provides a generator API (rapidjson::Writer
) which consumes the same set of events. - DOM (Document Object Model) style API
- Similar to DOM for
HTML/XML, RapidJSON can parse JSON into a DOM representation
(
rapidjson::GenericDocument
), for easy manipulation, and finally stringify back to JSON if needed. - The DOM style API (
rapidjson::GenericDocument
) is actually implemented with SAX style API (rapidjson::GenericReader
). SAX is faster but sometimes DOM is easier. Users can pick their choices according to scenarios.
Parsing
- Recursive (default) and iterative parser
- Recursive parser is faster but prone to stack overflow in extreme cases.
- Iterative parser use custom stack to keep parsing state.
- Support in situ parsing.
- Parse JSON string values in-place at the source JSON, and then the DOM points to addresses of those strings.
- Faster than convention parsing: no allocation for strings, no copy (if string does not contain escapes), cache-friendly.
- Support 32-bit/64-bit signed/unsigned integer and
double
for JSON number type. - Support parsing multiple JSONs in input stream
(
kParseStopWhenDoneFlag
). - Error Handling
- Support comprehensive error code if parsing failed.
- Support error message localization.
DOM (Document)
- RapidJSON checks range of numerical values for conversions.
- Optimization for string literal
- Only store pointer instead of copying
- Optimization for “short” strings
- Store short string in
Value
internally without additional allocation. - For UTF-8 string: maximum 11 characters in 32-bit, 21 characters in 64-bit (13 characters in x86-64).
- Optionally support
std::string
(defineRAPIDJSON_HAS_STDSTRING=1
)
Generation
- Support
rapidjson::PrettyWriter
for adding newlines and indentations.
Stream
- Support
rapidjson::GenericStringBuffer
for storing the output JSON as string. - Support
rapidjson::FileReadStream
andrapidjson::FileWriteStream
for input/outputFILE
object. - Support custom streams.
Memory
- Minimize memory overheads for DOM.
- Each JSON value occupies exactly 16/20 bytes for most 32/64-bit machines (excluding text string).
- Support fast default allocator.
- A stack-based allocator (allocate sequentially, prohibit to free individual allocations, suitable for parsing).
- User can provide a pre-allocated buffer. (Possible to parse a number of JSONs without any CRT allocation)
- Support standard CRT(C-runtime) allocator.
- Support custom allocators.
Miscellaneous
- Some C++11 support (optional)
- Rvalue reference
noexcept
specifier- Range-based for loop