add WebAssembly for Kws (#648)

wasm/kws/sherpa-onnx-wasm-main-kws.cc

@@ -0,0 +1,33 @@
+// wasm/sherpa-onnx-wasm-main-kws.cc
+//
+// Copyright (c)  2024  lovemefan
+#include <stdio.h>
+
+#include <algorithm>
+#include <memory>
+
+#include "sherpa-onnx/c-api/c-api.h"
+
+// see also
+// https://emscripten.org/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html
+
+extern "C" {
+
+static_assert(sizeof(SherpaOnnxOnlineTransducerModelConfig) == 3 * 4, "");
+static_assert(sizeof(SherpaOnnxOnlineParaformerModelConfig) == 2 * 4, "");
+static_assert(sizeof(SherpaOnnxOnlineZipformer2CtcModelConfig) == 1 * 4, "");
+static_assert(sizeof(SherpaOnnxOnlineModelConfig) ==
+                  sizeof(SherpaOnnxOnlineTransducerModelConfig) +
+                      sizeof(SherpaOnnxOnlineParaformerModelConfig) +
+                      sizeof(SherpaOnnxOnlineZipformer2CtcModelConfig) + 5 * 4,
+              "");
+static_assert(sizeof(SherpaOnnxFeatureConfig) == 2 * 4, "");
+static_assert(sizeof(SherpaOnnxKeywordSpotterConfig) ==
+                  sizeof(SherpaOnnxFeatureConfig) +
+                      sizeof(SherpaOnnxOnlineModelConfig) + 5 * 4,
+              "");
+
+void CopyHeap(const char *src, int32_t num_bytes, char *dst) {
+  std::copy(src, src + num_bytes, dst);
+}
+}