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Merged
DerThorsten merged 1 commit into from
Feb 6, 2026
+20 −16
Merged

use_typed_memory_view #126

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36 changes: 20 additions & 16 deletions src/convert.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -128,25 +128,29 @@ namespace pyjs
TypedArrayBuffer::TypedArrayBuffer(
em::val js_array, const std::string & format_descriptor
)
: m_size(js_array["length"].as<unsigned>()),
m_bytes_per_element(js_array["BYTES_PER_ELEMENT"].as<unsigned>()),
m_format_descriptor(format_descriptor),
m_data( new uint8_t[m_size * m_bytes_per_element] )
: m_size(js_array["length"].as<unsigned>()),
m_bytes_per_element(js_array["BYTES_PER_ELEMENT"].as<unsigned>()),
m_format_descriptor(format_descriptor),
m_data(new uint8_t[m_size * m_bytes_per_element])
{
em::val js_array_buffer = js_array["buffer"].as<em::val>();

const unsigned byte_offset = js_array["byteOffset"].as<em::val>().as<unsigned>();

// this is a uint8 view of the array
// Get the ArrayBuffer backing the JS TypedArray
em::val js_array_buffer = js_array["buffer"];

// Offset within the ArrayBuffer
const unsigned byte_offset = js_array["byteOffset"].as<unsigned>();

// Create a Uint8Array view of the source JS array
em::val js_uint8array = em::val::global("Uint8Array")
.new_(js_array_buffer, byte_offset, m_size * m_bytes_per_element);

em::val wasm_heap_allocated = js_uint8array["constructor"].new_(
em::val::module_property("HEAPU8")["buffer"],
reinterpret_cast<uintptr_t>(m_data),
m_size * m_bytes_per_element
);
wasm_heap_allocated.call<void>("set", js_uint8array);

// Create a typed_memory_view for the C++ buffer
em::val cpp_view = em::val(emscripten::typed_memory_view(
m_size * m_bytes_per_element,
m_data
));

// Copy data from JS array into C++ buffer
cpp_view.call<void>("set", js_uint8array);
}

TypedArrayBuffer::~TypedArrayBuffer(){
Expand Down