Adding camera enumerator project for getting ready for GUI

lib/3rdParty/CameraEnumerator/DeviceEnumerator.cpp

@@ -0,0 +1,123 @@
+#include "DeviceEnumerator.h"
+#include <iostream>
+
+std::map<int, Device> DeviceEnumerator::getVideoDevicesMap() {
+	return getDevicesMap(CLSID_VideoInputDeviceCategory);
+}
+
+std::map<int, Device> DeviceEnumerator::getAudioDevicesMap() {
+	return getDevicesMap(CLSID_AudioInputDeviceCategory);
+}
+
+// Returns a map of id and devices that can be used
+std::map<int, Device> DeviceEnumerator::getDevicesMap(const GUID deviceClass)
+{
+	std::map<int, Device> deviceMap;
+
+	// TODO add back? Calling from C# seems to not need this
+	//HRESULT hr = CoInitialize(nullptr);
+	//if (FAILED(hr)) {
+	//	return deviceMap; // Empty deviceMap as an error
+	//}
+
+	// Create the System Device Enumerator
+	ICreateDevEnum *pDevEnum;
+	HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pDevEnum));
+
+	// If succeeded, create an enumerator for the category
+	IEnumMoniker *pEnum = NULL;
+	if (SUCCEEDED(hr)) {
+		hr = pDevEnum->CreateClassEnumerator(deviceClass, &pEnum, 0);
+		if (hr == S_FALSE) {
+			hr = VFW_E_NOT_FOUND;
+		}
+		pDevEnum->Release();
+	}
+
+	// Now we check if the enumerator creation succeeded
+	int deviceId = -1;
+	if (SUCCEEDED(hr)) {
+		// Fill the map with id and friendly device name
+		IMoniker *pMoniker = NULL;
+		while (pEnum->Next(1, &pMoniker, NULL) == S_OK) {
+
+			IPropertyBag *pPropBag;
+			HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
+			if (FAILED(hr)) {
+				pMoniker->Release();
+				continue;
+			}
+
+			// Create variant to hold data
+			VARIANT var;
+			VariantInit(&var);
+
+			std::string deviceName;
+			std::string devicePath;
+
+			// Read FriendlyName or Description
+			hr = pPropBag->Read(L"Description", &var, 0); // Read description
+			if (FAILED(hr)) {
+				// If description fails, try with the friendly name
+				hr = pPropBag->Read(L"FriendlyName", &var, 0);
+			}
+			// If still fails, continue with next device
+			if (FAILED(hr)) {
+				VariantClear(&var);
+				continue;
+			}
+			// Convert to string
+			else {
+				deviceName = ConvertBSTRToMBS(var.bstrVal);
+			}
+
+			VariantClear(&var); // We clean the variable in order to read the next value
+
+								// We try to read the DevicePath
+			hr = pPropBag->Read(L"DevicePath", &var, 0);
+			if (FAILED(hr)) {
+				VariantClear(&var);
+				continue; // If it fails we continue with next device
+			}
+			else {
+				devicePath = ConvertBSTRToMBS(var.bstrVal);
+			}
+
+			// We populate the map
+			deviceId++;
+			Device currentDevice;
+			currentDevice.id = deviceId;
+			currentDevice.deviceName = deviceName;
+			currentDevice.devicePath = devicePath;
+			deviceMap[deviceId] = currentDevice;
+
+		}
+		pEnum->Release();
+	}
+	CoUninitialize();
+	return deviceMap;
+}
+
+/*
+This two methods were taken from
+https://stackoverflow.com/questions/6284524/bstr-to-stdstring-stdwstring-and-vice-versa
+*/
+
+std::string DeviceEnumerator::ConvertBSTRToMBS(BSTR bstr)
+{
+	int wslen = ::SysStringLen(bstr);
+	return ConvertWCSToMBS((wchar_t*)bstr, wslen);
+}
+
+std::string DeviceEnumerator::ConvertWCSToMBS(const wchar_t* pstr, long wslen)
+{
+	int len = ::WideCharToMultiByte(CP_ACP, 0, pstr, wslen, NULL, 0, NULL, NULL);
+
+	std::string dblstr(len, '\0');
+	len = ::WideCharToMultiByte(CP_ACP, 0 /* no flags */,
+		pstr, wslen /* not necessary NULL-terminated */,
+		&dblstr[0], len,
+		NULL, NULL /* no default char */);
+
+	return dblstr;
+}