These function wrap Niels Lohmann's JSON for Modern C++ class into mex wrappers, for fast reading of JSON files into MATLAB variables, and writing MATLAB variables into JSON files.
JSON for Modern C++ must be downloaded separately from:
Mex these functions by calling:
Note that your C++ compiler must support C++11.
Example usage: var = json_read(filename)
filename - String of filename (if in current directory) or full or relative path to the JSON file to be read in.
var - MATLAB interpretation of the JSON data.
Oliver Woodford (2021). C++ JSON IO (https://www.mathworks.com/matlabcentral/fileexchange/59166-c-json-io), MATLAB Central File Exchange. Retrieved .
json_write cannot be compiled as is. Include the "iomanip" and the "sstream" header files to compile it successfully.
Hi there, I cannot compile your code. Could you provide a pre-build version?
Very happy, was able to use this with coder. Must indicate not to compile the mex code, and then predefine the structure expected (and turn off warning that it's going to be overwritten)
Assuming my_settings.json is:
result.x = 0; %#ok<STRNU>
result = json_read('my_settings.json');
I suspect faster performance still can be achieved using the SAX API of the header only RapidJSON C++ library. https://github.com/miloyip/rapidjson/
Oleg: On the single 8MB file I have just tested it on, calling matlab.internal.webservices.fromJSON(fileread('myfile.json')) in R2016a is over 10 times slower than calling json_read (using timeit for the timing). This is no guarantee of performance on other files, of course.
How does it compare to the now (since R2016a) mexed version of matlab.internal.webservices.fromJSON()?
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