Streaming I/O and support of named pipes (#570)

* added streaming i/o for scripting, and a byteutil.get_size function

* added i/o stream class, also added named pipes support on lua side via ffi

* added constant file.named_pipes_prefix

* added buffered and yield modes for io_stream

* added new time function for work with UTC - utc_time, utc_offset, local_time

* docs updated

* constant pid moved to os.pid

* now gmtime_s and localtime_s used only in windows

src/logic/scripting/lua/libs/libtime.cpp

@@ -1,8 +1,13 @@
 #include "engine/Engine.hpp"
 #include "api_lua.hpp"
+#include <ctime>
 
 using namespace scripting;
 
+#if defined(_WIN32) || defined(_WIN64)
+    #define USE_MSVC_TIME_SAFE
+#endif
+
 static int l_uptime(lua::State* L) {
     return lua::pushnumber(L, engine->getTime().getTime());
 }
@@ -11,8 +16,57 @@ static int l_delta(lua::State* L) {
     return lua::pushnumber(L, engine->getTime().getDelta());
 }
 
+static int l_utc_time(lua::State* L) {
+    return lua::pushnumber(L, std::time(nullptr));
+}
+
+static int l_local_time(lua::State* L) {
+    std::time_t t = std::time(nullptr);
+
+    std::tm gmt_tm{};
+    std::tm local_tm{};
+
+#if defined(USE_MSVC_TIME_SAFE)
+    gmtime_s(&gmt_tm, &t);
+    localtime_s(&local_tm, &t);
+#else
+    gmtime_r(&t, &gmt_tm);
+    localtime_r(&t, &local_tm);
+#endif
+
+    std::time_t utc_time = std::mktime(&gmt_tm);
+    std::time_t local_time = std::mktime(&local_tm);
+    std::time_t offset = local_time - utc_time;
+
+    return lua::pushnumber(L, t + offset);
+}
+
+static int l_utc_offset(lua::State* L) {
+    std::time_t t = std::time(nullptr);
+
+    std::tm gmt_tm{};
+    std::tm local_tm{};
+
+#if defined(USE_MSVC_TIME_SAFE)
+    gmtime_s(&gmt_tm, &t);
+    localtime_s(&local_tm, &t);
+#else
+    gmtime_r(&t, &gmt_tm);
+    localtime_r(&t, &local_tm);
+#endif
+
+    std::time_t utc_time = std::mktime(&gmt_tm);
+    std::time_t local_time = std::mktime(&local_tm);
+    std::time_t offset = local_time - utc_time;
+
+    return lua::pushnumber(L, offset);
+}
+
 const luaL_Reg timelib[] = {
     {"uptime", lua::wrap<l_uptime>},
     {"delta", lua::wrap<l_delta>},
+    {"utc_time", lua::wrap<l_utc_time>},
+    {"utc_offset", lua::wrap<l_utc_offset>},
+    {"local_time", lua::wrap<l_local_time>},
     {NULL, NULL}
 };