1 files changed, 108 insertions, 0 deletions
diff --git a/c/win.cpp b/c/win.cpp
new file mode 100644
index 0000000..435e739
--- /dev/null
+++ b/c/win.cpp
@@ -0,0 +1,108 @@
+#include <utility>
+#include <windows.h>
+
+#include "win.h"
+
+Win32Error::Win32Error() : code(GetLastError()) {}
+Win32Error::Win32Error(const DWORD code) : code(code) {}
+
+Win32Error::~Win32Error()
+{
+	if (m_szMsg)
+		HeapFree(GetProcessHeap(), 0, m_szMsg);
+	if (m_wszMsg)
+		HeapFree(GetProcessHeap(), 0, m_wszMsg);
+}
+
+const char* Win32Error::what() const noexcept
+{
+	if (!m_szMsg)
+		FormatMessageA(
+		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
+		    NULL,
+		    code,
+		    MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
+		    (char*)&m_szMsg,
+		    0, NULL);
+	return m_szMsg;
+}
+
+const wchar_t* Win32Error::What() const noexcept
+{
+	if (!m_wszMsg)
+		FormatMessage(
+		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
+		    NULL,
+		    code,
+		    MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
+		    (wchar_t*)&m_wszMsg,
+		    0, NULL);
+	return m_wszMsg;
+}
+
+std::optional<Library> Library::Maybe(const wchar_t* const lib)
+{
+	HMODULE hModule = LoadLibrary(lib);
+	if (!hModule) return {};
+	return Library(hModule);
+}
+
+Library::Library(const HMODULE hModule) : m_hModule(hModule) {}
+
+Library::Library(const wchar_t* const lib)
+{
+	m_hModule = LoadLibrary(lib);
+	if (!m_hModule)
+		throw Win32Error();
+}
+
+Library::~Library()
+{
+	FreeLibrary(m_hModule);
+}
+
+int EBMessageBox(const wchar_t* const wszText, const wchar_t* const wszCaption, const unsigned uType)
+{
+	extern HWND g_hWnd;
+
+	auto proc = [](const int nCode, const WPARAM wParam, const LPARAM lParam) noexcept
+		-> LRESULT CALLBACK
+	{
+		if (!g_hWnd || nCode < 0 || nCode != HCBT_ACTIVATE)
+			return CallNextHookEx(0, nCode, wParam, lParam);
+
+		HWND hWnd = (HWND)wParam;
+		long lStyle = GetWindowLong(hWnd, GWL_STYLE);
+		if (!(lStyle & WS_POPUP)) return 0;
+
+		RECT rcMain, rcMsg;
+		GetWindowRect(g_hWnd, &rcMain);
+		GetWindowRect(hWnd, &rcMsg);
+		SetWindowPos(hWnd, NULL,
+		    rcMain.left+(rcMain.right-rcMain.left)/2-(rcMsg.right-rcMsg.left)/2,
+		    rcMain.top+(rcMain.bottom-rcMain.top)/2-(rcMsg.bottom-rcMsg.top)/2,
+		    -1, -1,
+		    SWP_NOZORDER|SWP_NOSIZE|SWP_NOACTIVATE);
+
+		return 0;
+	};
+
+	HHOOK hHook = require(SetWindowsHookEx(WH_CBT, proc, (HINSTANCE)NULL, GetCurrentThreadId()));
+	int r = MessageBox(g_hWnd, wszText, wszCaption, uType);
+	require(UnhookWindowsHookEx(hHook));
+	return r;
+}
+
+int GetRelativeCursorPos(HWND hWnd, POINT* pt)
+{
+	RECT rc;
+	if (!GetClientRect(hWnd, &rc)) return 0;
+	SetLastError(ERROR_SUCCESS);
+	if (!MapWindowPoints(hWnd, NULL, (POINT*)&rc, 2)) return 0;
+
+	POINT ptMouse;
+	if (!GetCursorPos(&ptMouse)) return 0;
+	pt->x = ptMouse.x-rc.left;
+	pt->y = ptMouse.y-rc.top;
+	return 1;
+}