If you declare your C++ function to return an emscripten::val, a memory
view should correctly marshal out and return a Uint8Array (or whichever
type you selected).
Here's an example in a getter on a value object, but it should work fine on
regular object methods too:
#include <emscripten/bind.h>
using namespace emscripten;
...
struct H264Plane {
unsigned char *data;
int stride;
int height;
...
val data_getter() const;
void data_setter(val v);
};
...
val H264Plane::data_getter() const
{
return val(memory_view<unsigned char>(stride * height, (unsigned
char *)data));
}
...
EMSCRIPTEN_BINDINGS(h264_decoder) {
value_object<H264Plane>("H264Plane")
.field("data", &H264Plane::data_getter,
&H264Plane::data_setter)
...
;
...
}
-- brion
On Fri, Aug 14, 2015 at 11:22 PM, Matthew Tamayo <[email protected]>
wrote:
> I've been looking around Emscripten to try and figure out how to marshall
> large binary objects from C++.
>
> We want to:
>
> 1. pass binaryArray = (unsigned *)&bigObject as a Uint8Array
> 2. Use XMLHttpRequest2 to send Uint8Array to server
> 3. Read in binary data on server (BigObject*) binaryArray in C++
>
> The problem we're having is figuring out the most efficient way to get a
> Uint8Array of emscripten using embind. I've seen some threads that
> recommend emscripten::memory_view(output_size, output_ptr), but I don't
> know if it requires passing in a JS function via emscripten::val or if
> returning a memory view will get correctly marshalled.
>
> Does this seem like sane approach? Any easier ways in the most recent
> version of emscripten?
>
> -mtr
>
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