Add mtime

src/core/os.h

@@ -86,6 +86,35 @@ namespace os
 #endif
 	}
 
+	/// Returns the last modification time of @a path.
+	inline uint64_t mtime(const char* path)
+	{
+#if CROWN_PLATFORM_POSIX
+		struct stat info;
+		memset(&info, 0, sizeof(struct stat));
+		int err = lstat(path, &info);
+		CE_ASSERT(err == 0, "lstat: errno = %d", errno);
+		CE_UNUSED(err);
+		return info.st_mtime;
+#elif CROWN_PLATFORM_WINDOWS
+		HANDLE hfile = CreateFile(path
+			, GENERIC_READ
+			, FILE_SHARE_READ
+			, NULL
+			, OPEN_EXISTING
+			, 0
+			, NULL
+			);
+		CE_ASSERT(hfile != INVALID_HANDLE_VALUE, "CreateFile: GetLastError = %d", GetLastError());
+		FILETIME ftwrite;
+		BOOL err = GetFileTime(hfile, NULL, NULL, &ftwrite);
+		CE_ASSERT(err != 0, "GetFileTime: GetLastError = %d", GetLastError());
+		CE_UNUSED(err);
+		CloseHandle(hfile);
+		return (uint64_t)((ftwrite.dwHighDateTime << 32) | ftwrite.dwLowDateTime);
+#endif
+	}
+
 	/// Creates a regular file.
 	inline void create_file(const char* path)
 	{