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Introduction
------------
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[JSON][json-org] is a lightweight data-interchange format. It can represent
numbers, strings, ordered sequences of values, and collections of name/value
pairs.
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[json-org]: http://json.org/
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JsonCpp is a C++ library that allows manipulating JSON values, including
serialization and deserialization to and from strings. It can also preserve
existing comment in unserialization/serialization steps, making it a convenient
format to store user input files.
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Using JsonCpp in your project
-----------------------------
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The recommended approach to integrating JsonCpp in your project is to build the
the amalgamated source (a single `.cpp` file) with your own build system. This
ensures consistency of compilation flags and ABI compatibility. See the section
"Generating amalgamated source and header" for instructions.
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The `include/` should be added to your compiler include path. Jsoncpp headers
should be included as follow:

    #include <json/json.h>

If JsonCpp was build as a dynamic library on Windows, then your project needs to
define the macro `JSON_DLL`.
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Building and testing with new CMake
-----------------------------------

[CMake][] is a C++ Makefiles/Solution generator. It is usually available on most
Linux system as package. On Ubuntu:

    sudo apt-get install cmake

[CMake]: http://www.cmake.org

Note that Python is also required to run the JSON reader/writer tests. If
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missing, the build will skip running those tests.
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When running CMake, a few parameters are required:
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* a build directory where the makefiles/solution are generated. It is also used
  to store objects, libraries and executables files.
* the generator to use: makefiles or Visual Studio solution? What version or
  Visual Studio, 32 or 64 bits solution? 

Steps for generating solution/makefiles using `cmake-gui`:

* Make "source code" point to the source directory.
* Make "where to build the binary" point to the directory to use for the build.
* Click on the "Grouped" check box.
* Review JsonCpp build options (tick `JSONCPP_LIB_BUILD_SHARED` to build as a
  dynamic library).
* Click the configure button at the bottom, then the generate button.
* The generated solution/makefiles can be found in the binary directory.

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Alternatively, from the command-line on Unix in the source directory:
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    mkdir -p ../build/debug
    cd ../build/debug
    cmake -DCMAKE_BUILD_TYPE=debug -DJSONCPP_LIB_BUILD_SHARED=OFF -G "Unix Makefiles" ../../jsoncpp-src
    make

Running `cmake -`" will display the list of available generators (passed using
the `-G` option).

By default CMake hides compilation commands. This can be modified by specifying
`-DCMAKE_VERBOSE_MAKEFILE=true` when generating makefiles.

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Building and testing with SCons
-------------------------------

**Note:** The SCons-based build system is deprecated. Please use CMake; see the
section above.

JsonCpp can use [Scons][] as a build system. Note that SCons requires python to
be installed.

[SCons]: http://www.scons.org/

Invoke SCons as follows:

    scons platform=PLTFRM [TARGET]

where `PLTFRM` may be one of:

* `suncc`: Sun C++ (Solaris)
* `vacpp`: Visual Age C++ (AIX)
* `mingw`
* `msvc6`: Microsoft Visual Studio 6 service pack 5-6
* `msvc70`: Microsoft Visual Studio 2002
* `msvc71`: Microsoft Visual Studio 2003
* `msvc80`: Microsoft Visual Studio 2005
* `msvc90`: Microsoft Visual Studio 2008
* `linux-gcc`: Gnu C++ (linux, also reported to work for Mac OS X)

If you are building with Microsoft Visual Studio 2008, you need to set up the
environment by running `vcvars32.bat` (e.g. MSVC 2008 command prompt) before
running SCons.


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Running the test manually
-------------------------
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Notes that test can be run by scons using the 'check' target (see above).

You need to run test manually only if you are troubleshooting an issue.

In the instruction below, replace "path to jsontest.exe" with the path
of the 'jsontest' executable that was compiled on your platform.
  
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cd test
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# This will run the Reader/Writer tests
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python runjsontests.py "path to jsontest.exe"
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# This will run the Reader/Writer tests, using JSONChecker test suite
# (http://www.json.org/JSON_checker/).
# Notes: not all tests pass: JsonCpp is too lenient (for example,
# it allows an integer to start with '0'). The goal is to improve
# strict mode parsing to get all tests to pass.
python runjsontests.py --with-json-checker "path to jsontest.exe"

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# This will run the unit tests (mostly Value)
python rununittests.py "path to test_lib_json.exe"

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You can run the tests using valgrind:
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python rununittests.py --valgrind "path to test_lib_json.exe"
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Building the documentation
--------------------------
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Run the python script doxybuild.py from the top directory:

python doxybuild.py --open --with-dot

See doxybuild.py --help for options. 

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Notes that the documentation is also available for download as a tarball. 
The documentation of the latest release is available online at:
http://jsoncpp.sourceforge.net/

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Generating amalgamated source and header
----------------------------------------
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JsonCpp is provided with a script to generate a single header and a single
source file to ease inclusion in an existing project.

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The amalgamated source can be generated at any time by running the following
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command from the top-directory (requires python 2.6):

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python amalgamate.py
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It is possible to specify header name. See -h options for detail. By default,
the following files are generated:
- dist/jsoncpp.cpp: source file that need to be added to your project
- dist/json/json.h: header file corresponding to use in your project. It is
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equivalent to including json/json.h in non-amalgamated source. This header
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only depends on standard headers. 
- dist/json/json-forwards.h: header the provides forward declaration
of all JsonCpp types. This typically what should be included in headers to
speed-up compilation.

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The amalgamated sources are generated by concatenating JsonCpp source in the
correct order and defining macro JSON_IS_AMALGAMATION to prevent inclusion
of other headers.
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Adding a reader/writer test
---------------------------
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To add a test, you need to create two files in test/data:
- a TESTNAME.json file, that contains the input document in JSON format.
- a TESTNAME.expected file, that contains a flatened representation of 
  the input document.
  
TESTNAME.expected file format:
- each line represents a JSON element of the element tree represented 
  by the input document.
- each line has two parts: the path to access the element separated from
  the element value by '='. Array and object values are always empty 
  (e.g. represented by either [] or {}).
- element path: '.' represented the root element, and is used to separate 
  object members. [N] is used to specify the value of an array element
  at index N.
See test_complex_01.json and test_complex_01.expected to better understand
element path.


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Understanding reader/writer test output
---------------------------------------
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When a test is run, output files are generated aside the input test files. 
Below is a short description of the content of each file:

- test_complex_01.json: input JSON document
- test_complex_01.expected: flattened JSON element tree used to check if 
    parsing was corrected.

- test_complex_01.actual: flattened JSON element tree produced by 
    jsontest.exe from reading test_complex_01.json
- test_complex_01.rewrite: JSON document written by jsontest.exe using the
    Json::Value parsed from test_complex_01.json and serialized using
    Json::StyledWritter.
- test_complex_01.actual-rewrite: flattened JSON element tree produced by 
    jsontest.exe from reading test_complex_01.rewrite.
test_complex_01.process-output: jsontest.exe output, typically useful to
    understand parsing error.
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License
-------
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See file LICENSE for details. Basically JsonCpp is licensed under 
MIT license, or public domain if desired and recognized in your jurisdiction.
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