Return output of jsmn json tokenizer to Matlab via mex

jsmn_mex.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "matrix.h"
#include "mex.h"
#include "jsmn.h"

 
//  mex jsmn_mex.c jsmn.c

void mexFunction( int nlhs, mxArray *plhs[], int nrhs, const mxArray*prhs[] )
{
    // str = fileread(file_path);
    // token_info = jsmn_mex(str)
    //
    //  token_info: see jsmn.h structure
    
    int n;
    int r2;
    char *json_string;
    jsmn_parser p;
    jsmntok_t *t;
    size_t string_byte_length;
    
    json_string = mxArrayToString(prhs[0]);
    string_byte_length = mxGetNumberOfElements(prhs[0]);
    
    //TODO: Allow a memory hungry allocation of tokens (1/3 of file length?)
    
    
    //Initial pass through, get # of tokens
    jsmn_init(&p);
	n = jsmn_parse(&p, json_string, string_byte_length, NULL, 0);
    
    //Allocate output and reparse
    t = mxMalloc(n*sizeof(jsmntok_t));
    jsmn_init(&p);
    r2 = jsmn_parse(&p, json_string, strlen(json_string), t, n);
    
    plhs[0] = mxCreateNumericArray(0, 0, mxUINT32_CLASS, mxREAL);
    
    mxSetData(plhs[0], t);
    mxSetM(plhs[0], sizeof(jsmntok_t)/4);
    mxSetN(plhs[0], n);
    
}