webcamservice/GetCameraDeviceID.cpp

#include <atlcomcli.h>
#include "GetCameraDeviceID.h"
#pragma comment(lib,"strmiids.lib")

//Converting a WChar string to a Ansi string  
static string WChar2Ansi(LPCWSTR pwszSrc)
{
	int nLen = WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, NULL, 0, NULL, NULL);

	if (nLen <= 0) return string("");

	char* pszDst = new char[nLen];
	if (NULL == pszDst) return string("");

	WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, pszDst, nLen, NULL, NULL);
	pszDst[nLen - 1] = 0;

	string strTemp(pszDst);
	delete[] pszDst;

	return strTemp;
}
static string ws2s(const wstring& inputws) { return WChar2Ansi(inputws.c_str()); }
/*
功能：通过设备的VID与PID获取对应的ID
入口参数：
[in] vid：设备VID
[in] pid：设备PID
返回值：
获取到的设备ID，-1:指定设备不存在
*/
int GetDeviceIDfromVIDandPID(string vid, string pid)
{
	if (FAILED(CoInitialize(NULL)))
	{
		cout << "CoInitialize Failed ..." << endl;
		return -1;
	}

	transform(vid.begin(), vid.end(), vid.begin(), ::tolower);
	transform(pid.begin(), pid.end(), pid.begin(), ::tolower);

	int id = 0;
	ICreateDevEnum *pCreateDevEnum;
	HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,
		CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void**)&pCreateDevEnum);
	if (hr != NOERROR)
		return -1;

	ATL::CComPtr<IEnumMoniker> pEm;
	hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEm, 0);
	if (hr != NOERROR)
		return -1;
	pEm->Reset();

	ULONG cFetched;
	IMoniker *pM;
	while (hr = pEm->Next(1, &pM, &cFetched), hr == S_OK)
	{
		wstring	str = L"";
		wstring	strVid, strPid;
		int		Count = 0;

		IPropertyBag *pBag;
		hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag);
		if (SUCCEEDED(hr))
		{
			VARIANT var;
			var.vt = VT_BSTR;
			hr = pBag->Read(L"DevicePath", &var, NULL);

			if (hr == 0)
			{
				while (var.bstrVal[Count] != 0x00)
				{
					str += var.bstrVal[Count];
					Count++;
				}

				strVid = str.substr(str.find(L"vid_") + 4, 4);
				strPid = str.substr(str.find(L"pid_") + 4, 4);

				string tmpVid = ws2s(strVid);
				string tmpPid = ws2s(strPid);

				//cout << "Vid:" << tmpVid << "     Pid:" << tmpPid << endl;

				if (0 == strcmp(tmpVid.c_str(), vid.c_str()) && 0 == strcmp(tmpPid.c_str(), pid.c_str()))
				{
					return id;
					break;
				}
			}

			id++;

			pBag->Release();
		}
		pM->Release();
	}
	return -1;
}

int EnumCameraDevices(vector<CameraDev> & cameras)
{
	cameras.clear();

	if (FAILED(CoInitialize(NULL)))
	{
		cout << "CoInitialize Failed ..." << endl;
		return -1;
	}

	int id = 0;
	ICreateDevEnum *pCreateDevEnum;
	HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,
		CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, (void**)&pCreateDevEnum);
	if (hr != NOERROR)
		return -1;

	ATL::CComPtr<IEnumMoniker> pEm;
	hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEm, 0);
	if (hr != NOERROR)
		return -1;
	pEm->Reset();

	ULONG cFetched;
	IMoniker *pM;
	while (hr = pEm->Next(1, &pM, &cFetched), hr == S_OK)
	{
		IPropertyBag *pBag;
		hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag);
		if (SUCCEEDED(hr))
		{
			CameraDev TmpCam;
			TmpCam.devID = id;

			VARIANT var;
			var.vt = VT_BSTR;
			hr = pBag->Read(L"DevicePath", &var, NULL);
			if (hr == 0)
			{
				wstring	str = L"";
				wstring	strVid, strPid;
				int		Count = 0;
				while (var.bstrVal[Count] != 0x00)
				{
					str += var.bstrVal[Count];
					Count++;
				}

				strVid = str.substr(str.find(L"vid_") + 4, 4);
				strPid = str.substr(str.find(L"pid_") + 4, 4);

				TmpCam.devVId = ws2s(strVid);
				TmpCam.devPId = ws2s(strPid);
			}

			VARIANT var1;
			var1.vt = VT_BSTR;
			hr = pBag->Read(L"FriendlyName", &var1, NULL);
			if (hr == 0)
			{
				wstring	str = L"";
				int		Count = 0;
				while (var1.bstrVal[Count] != 0x00)
				{
					str += var1.bstrVal[Count];
					Count++;
				}

				TmpCam.devName = ws2s(str);
			}

			if (TmpCam.devName.find("screen-capture-recorder") == -1)
			{
				cameras.push_back(TmpCam);
				id++;
			}

			pBag->Release();
		}
		pM->Release();
	}
	return id;
}