code_twain/twain/load_sane.cpp

#include "pch.h"
#include "load_sane.h"
#include <string>

namespace load_sane_util
{
	static std::wstring sane_path(L"");
	static HMODULE		sane_module(NULL);
	static int (__stdcall* sane_inst)(SCANNERID, ISaneInvoker**) = NULL;
	static int(__stdcall* is_on)(SCANNERID) = NULL;
	static int(__stdcall* init)(void*) = NULL;
	static int(__stdcall* uninit)(void*) = NULL;

	static std::wstring reg_read(HKEY root, const wchar_t* path, const wchar_t* name)
	{
		HKEY	key = NULL;

		RegOpenKeyW(root, path, &key);
		if (!key)
			return L"";

		wchar_t* buf = NULL;
		DWORD	len = 0;
		DWORD	type = REG_SZ;
		std::wstring ret(L"");

		RegQueryValueExW(key, name, NULL, &type, (LPBYTE)buf, &len);
		if (len)
		{
			buf = new wchar_t[len + 4];
			memset(buf, 0, (len + 4) * sizeof(*buf));
			RegQueryValueExW(key, name, NULL, &type, (LPBYTE)buf, &len);
			ret = buf;
			delete[] buf;
		}
		RegCloseKey(key);

		return ret;
	}
	static std::wstring reg_get_app_installing_path(void)
	{
#ifdef OEM_HANWANG
		std::wstring path(L"SOFTWARE\\HanvonScan");
#elif defined(OEM_LISICHENG)
		std::wstring path(L"SOFTWARE\\LanxumScan");
#else
		std::wstring path(L"SOFTWARE\\HuaGoScan");
#endif

		return reg_read(HKEY_LOCAL_MACHINE, path.c_str(), L"AppDirectory");
	}
	static int load_dll(const wchar_t* path_dll, HMODULE* dll)
	{
		HMODULE h = LoadLibraryW(path_dll);
		int		ret = GetLastError();

		if (!h && ret == ERROR_MOD_NOT_FOUND)
		{
			std::wstring	dir(path_dll);
			size_t			pos = dir.rfind(L'\\');
			wchar_t			path[MAX_PATH] = { 0 };

			GetCurrentDirectoryW(_countof(path) - 1, path);
			if (pos != std::wstring::npos)
				dir.erase(pos);
			SetCurrentDirectoryW(dir.c_str());
			h = LoadLibraryW(path_dll);
			ret = GetLastError();
			SetCurrentDirectoryW(path);
		}

		if (dll)
			*dll = h;

		return ret;
	}
	static std::string u2m(const wchar_t* u, int page)
	{
		char* ansi = NULL;
		int		len = 0;
		std::string mb("");

		len = WideCharToMultiByte(page, 0, u, lstrlenW(u), NULL, 0, NULL, NULL);
		ansi = new char[len + 2];
		len = WideCharToMultiByte(page, 0, u, lstrlenW(u), ansi, len, NULL, NULL);
		ansi[len--] = 0;
		mb = ansi;
		delete[] ansi;

		return mb;
	}
	static std::wstring m2u(const char* m, int page)
	{
		wchar_t* unic = NULL;
		int		len = 0;
		std::wstring u(L"");

		len = MultiByteToWideChar(page, 0, m, lstrlenA(m), NULL, 0);
		unic = new wchar_t[len + 2];
		len = MultiByteToWideChar(page, 0, m, lstrlenA(m), unic, len);
		unic[len--] = 0;
		u = unic;
		delete[] unic;

		return u;
	}

	bool initialize(HMODULE me)
	{
		bool ret = false;
		sane_path = reg_get_app_installing_path();
		if (!sane_path.empty())
		{
			sane_path += L"\\sane.dll";
			load_dll(sane_path.c_str(), &sane_module);
			if (sane_module)
			{
				*((FARPROC*)&init) = GetProcAddress(sane_module, "initialize");
				*((FARPROC*)&sane_inst) = GetProcAddress(sane_module, "open_scanner");
				*((FARPROC*)&is_on) = GetProcAddress(sane_module, "is_scanner_online");
				*((FARPROC*)&uninit) = GetProcAddress(sane_module, "uninitialize");
				ret = is_ok();
				if (ret)
					ret = init(NULL) == 0;
			}
		}

		return ret;
	}
	bool is_ok(void)
	{
		return sane_inst != NULL && is_on != NULL && init != NULL && uninit != NULL;
	}
	bool is_online(SCANNERID guid)
	{
		if (is_on)
			return is_on(guid);
		else
			return false;
	}
	ISaneInvoker* open(SCANNERID guid, int* err)
	{
		ISaneInvoker* ret = NULL;
		int	code = 0;

		if (!err)
			err = &code;

		if (sane_inst)
			*err = sane_inst(guid, &ret);

		return ret;
	}
	void uninitialize(void)
	{
		if (uninit)
			uninit(NULL);

		if (sane_module)
		{
			FreeLibrary(sane_module);
			sane_module = NULL;
		}
		sane_path = L"";
		sane_inst = NULL;
	}

	std::string utf82ansi(const char* utf8)
	{
		return u2m(m2u(utf8, CP_UTF8).c_str(), CP_ACP);
	}
	std::string ansi2utf8(const char* ansi)
	{
		return u2m(m2u(ansi, CP_ACP).c_str(), CP_UTF8);
	}
};