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137 lines (111 loc) · 4.84 KB
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/**
\mainpage
\section _intro Introduction
<a HREF="http://www.json.org/">JSON (JavaScript Object Notation)</a>
is a lightweight data-interchange format.
Here is an example of JSON data:
\verbatim
{
"encoding" : "UTF-8",
"plug-ins" : [
"python",
"c++",
"ruby"
],
"indent" : { "length" : 3, "use_space": true }
}
\endverbatim
<b>JsonCpp</b> supports comments as <i>meta-data</i>:
\code
// Configuration options
{
// Default encoding for text
"encoding" : "UTF-8",
// Plug-ins loaded at start-up
"plug-ins" : [
"python",
"c++", // trailing comment
"ruby"
],
// Tab indent size
// (multi-line comment)
"indent" : { /*embedded comment*/ "length" : 3, "use_space": true }
}
\endcode
\section _features Features
- read and write JSON document
- attach C++ style comments to element during parsing
- rewrite JSON document preserving original comments
Notes: Comments used to be supported in JSON but were removed for
portability (C like comments are not supported in Python). Since
comments are useful in configuration/input file, this feature was
preserved.
\section _example Code example
\code
Json::Value root; // 'root' will contain the root value after parsing.
std::cin >> root; // Or see CharReaderBuilder.
// Get the value of the member of root named 'encoding', return 'UTF-8' if there is no
// such member.
std::string encoding = root.get("encoding", "UTF-8" ).asString();
// Get the value of the member of root named 'encoding', return a 'null' value if
// there is no such member.
const Json::Value plugins = root["plug-ins"];
for ( int index = 0; index < plugins.size(); ++index ) // Iterates over the sequence elements.
loadPlugIn( plugins[index].asString() );
setIndentLength( root["indent"].get("length", 3).asInt() );
setIndentUseSpace( root["indent"].get("use_space", true).asBool() );
// Since Json::Value has implicit constructor for all value types, it is not
// necessary to explicitly construct the Json::Value object:
root["encoding"] = getCurrentEncoding();
root["indent"]["length"] = getCurrentIndentLength();
root["indent"]["use_space"] = getCurrentIndentUseSpace();
// (NEW IN 1.4.0)
// To write into a stream with minimal memory overhead,
// create a Builder for a StreamWriter.
Json::StreamWriterBuilder builder;
builder.indentation_ = " "; // or whatever you like
// Then build a StreamWriter.
std::shared_ptr<Json::StreamWriter> writer(
builder.newStreamWriter( &std::cout ) );
// Make a new JSON document for the configuration. Preserve original comments.
writer->write( root );
// If you like the defaults, you can insert directly into a stream.
std::cout << root;
// If desired, remember to add a linefeed and flush.
std::cout << std::endl;
// Of course, you can write to `std::ostringstream` if you prefer. Or
// use `writeString()` for convenience.
std::string document = Json::writeString( root, builder );
// You can also read from a stream. This will put the contents of any JSON
// stream at a particular sub-value, if you'd like.
std::cin >> root["subtree"];
\endcode
\section _pbuild Build instructions
The build instructions are located in the file
<a HREF="https://github.com/open-source-parsers/jsoncpp/blob/master/README.md">README.md</a> in the top-directory of the project.
The latest version of the source is available in the project's GitHub repository:
<a HREF="https://github.com/open-source-parsers/jsoncpp/">
jsoncpp</a>
\section _news What's New?
The description of latest changes can be found in
<a HREF="https://github.com/open-source-parsers/jsoncpp/wiki/NEWS">
the NEWS wiki
</a>.
\section _rlinks Related links
- <a HREF="http://www.json.org/">JSON</a> Specification and alternate language implementations.
- <a HREF="http://www.yaml.org/">YAML</a> A data format designed for human readability.
- <a HREF="http://www.cl.cam.ac.uk/~mgk25/unicode.html">UTF-8 and Unicode FAQ</a>.
\section _plinks Old project links
- <a href="https://sourceforge.net/projects/jsoncpp/">https://sourceforge.net/projects/jsoncpp/</a>
- <a href="http://jsoncpp.sourceforge.net">http://jsoncpp.sourceforge.net</a>
- <a href="http://sourceforge.net/projects/jsoncpp/files/">http://sourceforge.net/projects/jsoncpp/files/</a>
- <a href="http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/">http://jsoncpp.svn.sourceforge.net/svnroot/jsoncpp/trunk/</a>
- <a href="http://jsoncpp.sourceforge.net/old.html">http://jsoncpp.sourceforge.net/old.html</a>
\section _license License
See file <a href="https://github.com/open-source-parsers/jsoncpp/blob/master/LICENSE"><code>LICENSE</code></a> in the top-directory of the project.
Basically JsonCpp is licensed under MIT license, or public domain if desired
and recognized in your jurisdiction.
\author Baptiste Lepilleur <blep@users.sourceforge.net> (originator)
\version \include version
\sa version.h
*/