Export C functions for other languages

CMakeLists.txt

@@ -24,12 +24,17 @@ else()
 
     add_library(decoder
                 src/decoder.cpp
+                src/decoder_c.cpp
                 )
 
+    set_target_properties(decoder PROPERTIES
+        PUBLIC_HEADER shared/theengs.h)
+
     target_include_directories(decoder
         PUBLIC
             $<INSTALL_INTERFACE:arduino_json>
             $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src/arduino_json/src>
+            ${CMAKE_CURRENT_SOURCE_DIR}/include
             ${CMAKE_CURRENT_SOURCE_DIR}/src
     )
 

examples/go/README.md

@@ -0,0 +1,21 @@
+# Go demo
+
+## Prerequisites
+
+The decoder library should be compiled statically when using it with Go.
+
+From the decoder root folder
+
+```sh
+mkdir -p build
+cd build
+cmake -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTING=OFF ..
+make
+```
+
+# Running
+The example can now be ran
+
+```sh
+go run decode.go
+```

examples/go/decoder.go

@@ -0,0 +1,69 @@
+package main
+
+// #cgo LDFLAGS: -lstdc++ -L../../build -ldecoder
+// #include "../../include/shared/theengs.h"
+// #include "stdlib.h"
+import "C"
+
+import (
+	"log"
+	"unsafe"
+)
+
+type TheengsDecoder struct {
+	ptr unsafe.Pointer
+}
+
+func NewDecoder() TheengsDecoder {
+	return TheengsDecoder{
+		ptr: C.Theengs_NewDecoder(),
+	}
+}
+
+func (d TheengsDecoder) Destroy() {
+	C.Theengs_DestroyDecoder(d.ptr)
+}
+
+func (d TheengsDecoder) DecodeBLE(json_data string) string {
+	cs_data := C.CString(json_data)
+	cs_result := C.Theengs_DecodeBLE(d.ptr, cs_data)
+	result := C.GoString(cs_result)
+	C.free(unsafe.Pointer(cs_data))
+	C.free(unsafe.Pointer(cs_result))
+	return result
+}
+
+func (d TheengsDecoder) GetProperties(model_id string) string {
+	cs_model := C.CString(model_id)
+	cs_result := C.Theengs_GetProperties(d.ptr, cs_model)
+	result := C.GoString(cs_result)
+	C.free(unsafe.Pointer(cs_model))
+	C.free(unsafe.Pointer(cs_result))
+	return result
+}
+
+func (d TheengsDecoder) GetAttribute(model_id string, attribute string) string {
+	cs_model := C.CString(model_id)
+	cs_attr := C.CString(attribute)
+	cs_result := C.Theengs_GetAttribute(d.ptr, cs_model, cs_attr)
+	result := C.GoString(cs_result)
+	C.free(unsafe.Pointer(cs_model))
+	C.free(unsafe.Pointer(cs_attr))
+	C.free(unsafe.Pointer(cs_result))
+	return result
+}
+
+func main() {
+
+	json_data := `{"id":"redacted","mac_type":0,"adv_type":0,"name":"LYWSD02","rssi":-67,"servicedata":"70205b043941e480012ee7090a10012500","servicedatauuid":"0xfe95"}`
+
+	decoder := NewDecoder()
+	data := decoder.DecodeBLE(json_data)
+	props := decoder.GetProperties("LYWSD02")
+	brand := decoder.GetAttribute("LYWSD02", "brand")
+	model := decoder.GetAttribute("LYWSD02", "model")
+
+	log.Println(data)
+	log.Println(props)
+	log.Printf("brand: %v, model: %v\n", brand, model)
+}

examples/go/dummy.cpp

@@ -0,0 +1,2 @@
+// Go won't use the C++ linker unless it detects at least one cpp file
+// This file serves no other purpose

include/shared/theengs.h

@@ -0,0 +1,39 @@
+/*
+    TheengsDecoder - Decode things and devices
+
+    Copyright: (c)Florian ROBERT
+
+    This file is part of TheengsDecoder.
+
+    TheengsDecoder is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    TheengsDecoder is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _THEENGS_H_
+#define _THEENGS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void* Theengs_NewDecoder();
+void Theengs_DestroyDecoder(void* decoder);
+const char* Theengs_DecodeBLE(void* decoder, const char* json_data);
+const char* Theengs_GetProperties(void* decoder, const char* model_id);
+const char* Theengs_GetAttribute(void* decoder, const char* model_id, const char* attribute);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // _THEENGS_H_

src/decoder_c.cpp

@@ -0,0 +1,64 @@
+/*
+    TheengsDecoder - Decode things and devices
+
+    Copyright: (c)Florian ROBERT
+
+    This file is part of TheengsDecoder.
+
+    TheengsDecoder is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    TheengsDecoder is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <string.h>
+
+#include "decoder.h"
+#include "shared/theengs.h"
+
+// Utility function local to the bridge's implementation
+TheengsDecoder* AsDecoder(void* decoder) { return reinterpret_cast<TheengsDecoder*>(decoder); }
+
+void* Theengs_NewDecoder() {
+  auto decoder = new TheengsDecoder();
+  return decoder;
+}
+
+void Theengs_DestroyDecoder(void* decoder) {
+  AsDecoder(decoder)->~TheengsDecoder();
+}
+
+const char* Theengs_DecodeBLE(void* decoder, const char* json_data) {
+  StaticJsonDocument<1024> doc;
+  DeserializationError err = deserializeJson(doc, json_data);
+  if (!err) {
+    JsonObject bleObject;
+    bleObject = doc.as<JsonObject>();
+
+    if (AsDecoder(decoder)->decodeBLEJson(bleObject) >= 0) {
+      std::string buf;
+      serializeJson(bleObject, buf);
+      return strdup(buf.c_str());
+    }
+  }
+  return "";
+}
+
+const char* Theengs_GetProperties(void* decoder, const char* model_id) {
+  std::string props = AsDecoder(decoder)->getTheengProperties(model_id);
+  return strdup(props.c_str());
+}
+
+const char* Theengs_GetAttribute(void* decoder, const char* model_id, const char* attribute) {
+  std::string attrs = AsDecoder(decoder)->getTheengAttribute(model_id, attribute);
+  return strdup(attrs.c_str());
+}