How to operate on TypedArray in C++

Hi Ben,

there is no specific API at the moment to do a copy-less conversion, although we have plan to add it soon. In duetto 0.9.6 and the upcoming 1.0 release you can use the following hack to access a typed array like a plain pointer:

        Int8Array* ar=new Int8Array(4);
        char* volatile c=(char*)(Array*)ar;
        c[2] = 42;

Please be careful in using the right C data type for any given typed array to guarantee correct results. The apparently useless double cast is necessary. Again, we plan to add a cleaner solution in future, but this should work and no copy is made.

Thanks, that looks suitable for use with Browser APIs within the C++. What if I want to pass TypedArrays to a C++ method from the JS? What signature do I need on the C++ method?

e.g. I want to do:

In JS
var obj = new Object();
var input_array = some typed array;
var output_array = some typed array;
obj.method(input_array, output_array);

In C++
class Object [[jsexport]] {
public:
  void method(<what signature here?>) {
      <use C pointers to access the TypedArrays here>
   }

ben

You can use two different approaches:

1) Use client::Int8Array (or any typed array) and convert to pointer to data on the C++ side, like shown above
2) Forge a duetto compatible pointer on the javascript side, using the following syntax
     obj.method( { d: input_array, o: 0}, { d:output_array, o: 0})

I used 2) above - and a C++ signature of void method(unsigned char*, unsigned char*).