LuaPushPull.h

Go to the documentation of this file.

// Copyright © 2008-2023 Pioneer Developers. See AUTHORS.txt for details
// Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
#ifndef _LUAPUSHPULL_H
#define _LUAPUSHPULL_H
 
#include "Lua.h"
#include "buildopts.h"
#include <lua.hpp>
 
#include <cstddef>
#include <string>
#include <tuple>
 
inline void pi_lua_generic_push(lua_State *l, bool value) { lua_pushboolean(l, value); }
inline void pi_lua_generic_push(lua_State *l, int value) { lua_pushinteger(l, value); }
inline void pi_lua_generic_push(lua_State *l, int64_t value) { lua_pushinteger(l, value); }
inline void pi_lua_generic_push(lua_State *l, unsigned int value) { lua_pushinteger(l, value); }
#if SIZE_T_AND_UNSIGNED_INT_ARE_DIFFERENT_TYPES
inline void pi_lua_generic_push(lua_State *l, size_t value) { lua_pushinteger(l, value); }
#endif
inline void pi_lua_generic_push(lua_State *l, double value) { lua_pushnumber(l, value); }
inline void pi_lua_generic_push(lua_State *l, const char *value) { lua_pushstring(l, value); }
inline void pi_lua_generic_push(lua_State *l, const std::string &value)
{
    lua_pushlstring(l, value.c_str(), value.size());
}
inline void pi_lua_generic_push(lua_State *l, std::string_view &value)
{
    lua_pushlstring(l, value.data(), value.size());
}
inline void pi_lua_generic_push(lua_State *l, const std::nullptr_t &value) { lua_pushnil(l); }
 
inline void pi_lua_generic_pull(lua_State *l, int index, bool &out) { out = lua_toboolean(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, int &out) { out = luaL_checkinteger(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, int64_t &out) { out = luaL_checkinteger(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, unsigned int &out) { out = luaL_checkunsigned(l, index); }
#if SIZE_T_AND_UNSIGNED_INT_ARE_DIFFERENT_TYPES
inline void pi_lua_generic_pull(lua_State *l, int index, size_t &out) { out = luaL_checkunsigned(l, index); }
#endif
inline void pi_lua_generic_pull(lua_State *l, int index, float &out) { out = luaL_checknumber(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, double &out) { out = luaL_checknumber(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, const char *&out) { out = luaL_checkstring(l, index); }
inline void pi_lua_generic_pull(lua_State *l, int index, std::string &out)
{
    size_t len;
    const char *buf = luaL_checklstring(l, index, &len);
    std::string(buf, len).swap(out);
}
// the returned string view is only valid until the lua object is removed from the stack
inline void pi_lua_generic_pull(lua_State *l, int index, std::string_view &out)
{
    size_t len;
    const char *buf = luaL_checklstring(l, index, &len);
    out = { buf, len };
}
 
template <typename Type>
inline void LuaPush(lua_State *l, Type value)
{
    pi_lua_generic_push(l, value);
}
 
template <typename Type>
inline std::remove_reference_t<Type> LuaPull(lua_State *l, int index)
{
    std::decay_t<Type> value;
    pi_lua_generic_pull(l, index, value);
    return value;
}
 
// Pull a value with an optional default.
template <typename Type>
inline Type LuaPull(lua_State *l, int index, Type defaultVal)
{
    Type value = defaultVal;
    if (lua_gettop(l) >= index && !lua_isnil(l, index))
        pi_lua_generic_pull(l, index, value);
    return value;
}
 
inline bool pi_lua_strict_pull(lua_State *l, int index, bool &out)
{
    if (lua_type(l, index) == LUA_TBOOLEAN) {
        out = lua_toboolean(l, index);
        return true;
    }
    return false;
}
inline bool pi_lua_strict_pull(lua_State *l, int index, int &out)
{
    if (lua_type(l, index) == LUA_TNUMBER) {
        out = lua_tointeger(l, index);
        return true;
    }
    return false;
}
inline bool pi_lua_strict_pull(lua_State *l, int index, float &out)
{
    if (lua_type(l, index) == LUA_TNUMBER) {
        out = lua_tonumber(l, index);
        return true;
    }
    return false;
}
inline bool pi_lua_strict_pull(lua_State *l, int index, double &out)
{
    if (lua_type(l, index) == LUA_TNUMBER) {
        out = lua_tonumber(l, index);
        return true;
    }
    return false;
}
inline bool pi_lua_strict_pull(lua_State *l, int index, const char *&out)
{
    if (lua_type(l, index) == LUA_TSTRING) {
        out = lua_tostring(l, index);
        return true;
    }
    return false;
}
inline bool pi_lua_strict_pull(lua_State *l, int index, std::string &out)
{
    if (lua_type(l, index) == LUA_TSTRING) {
        size_t len;
        const char *buf = lua_tolstring(l, index, &len);
        std::string(buf, len).swap(out);
        return true;
    }
    return false;
}
template <typename... Types>
inline void pi_lua_multiple_push(lua_State *l, Types... args);
 
#if defined(_MSC_VER) // Non-variadic version for MSVC
template <typename Arg1>
inline void pi_lua_multiple_push(lua_State *l, Arg1 arg1)
{
    pi_lua_generic_push(l, arg1);
}
 
template <typename Arg1, typename Arg2>
inline void pi_lua_multiple_push(lua_State *l, Arg1 arg1, Arg2 arg2)
{
    pi_lua_generic_push(l, arg1);
    pi_lua_generic_push(l, arg2);
}
 
template <typename Arg1, typename Arg2, typename Arg3>
inline void pi_lua_multiple_push(lua_State *l, Arg1 arg1, Arg2 arg2, Arg3 arg3)
{
    pi_lua_generic_push(l, arg1);
    pi_lua_generic_push(l, arg2);
    pi_lua_generic_push(l, arg3);
}
 
template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
inline void pi_lua_multiple_push(lua_State *l, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4)
{
    pi_lua_generic_push(l, arg1);
    pi_lua_generic_push(l, arg2);
    pi_lua_generic_push(l, arg3);
    pi_lua_generic_push(l, arg4);
}
#else // Just use the normal variadic version
template <typename Head, typename... Tail>
inline void pi_lua_multiple_push(lua_State *l, Head arg1, Tail... rest)
{
    pi_lua_generic_push(l, arg1);
    pi_lua_multiple_push(l, rest...);
}
#endif
 
inline void pi_lua_multiple_push(lua_State *l)
{
    return;
}
 
#if defined(_MSC_VER)
template <typename Arg1, typename Arg2>
inline std::tuple<Arg1, Arg2> pi_lua_multiple_pull(lua_State *l, int beg)
{
    beg = lua_absindex(l, beg);
    Arg1 arg1;
    Arg2 arg2;
    pi_lua_generic_pull(l, beg, arg1);
    pi_lua_generic_pull(l, beg + 1, arg2);
    return std::make_tuple(arg1, arg2);
}
template <typename Arg1, typename Arg2, typename Arg3>
inline std::tuple<Arg1, Arg2, Arg3> pi_lua_multiple_pull(lua_State *l, int beg)
{
    beg = lua_absindex(l, beg);
    Arg1 arg1;
    Arg2 arg2;
    Arg3 arg3;
    pi_lua_generic_pull(l, beg, arg1);
    pi_lua_generic_pull(l, beg + 1, arg2);
    pi_lua_generic_pull(l, beg + 2, arg3);
    return std::make_tuple(arg1, arg2, arg3);
}
template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
inline std::tuple<Arg1, Arg2, Arg3, Arg4> pi_lua_multiple_pull(lua_State *l, int beg)
{
    beg = lua_absindex(l, beg);
    Arg1 arg1;
    Arg2 arg2;
    Arg3 arg3;
    Arg4 arg4;
    pi_lua_generic_pull(l, beg, arg1);
    pi_lua_generic_pull(l, beg + 1, arg2);
    pi_lua_generic_pull(l, beg + 2, arg3);
    pi_lua_generic_pull(l, beg + 3, arg4);
    return std::make_tuple(arg1, arg2, arg3, arg4);
}
#else
// The _bogus parameter is used to bring the empty type list case into the template world
// to solve name resolution problems.
template <int _bogus, typename Head, typename... Tail>
inline std::tuple<Head, Tail...> __helper_pi_lua_multiple_pull(lua_State *l, int beg)
{
    beg = lua_absindex(l, beg);
    std::tuple<Tail...> rest = __helper_pi_lua_multiple_pull<_bogus, Tail...>(l, beg + 1);
    Head hd;
    pi_lua_generic_pull(l, beg, hd);
    std::tuple<Head> first(hd);
    return std::tuple_cat(first, rest);
}
 
template <int _bogus>
inline std::tuple<> __helper_pi_lua_multiple_pull(lua_State *l, int beg)
{
    return std::tuple<>();
}
 
template <typename... Types>
inline std::tuple<Types...> pi_lua_multiple_pull(lua_State *l, int beg)
{
    return __helper_pi_lua_multiple_pull<0, Types...>(l, beg);
}
#endif
 
#endif