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/*
Minetest
Copyright (C) 2022 sfan5 <sfan5@live.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#pragma once
#include <string>
#include <vector>
#include "irrlichttypes.h"
#include "util/basic_macros.h"
extern "C" {
#include <lua.h>
}
/*
This file defines an in-memory representation of Lua objects including
support for functions and userdata. It it used to move data between Lua
states and cannot be used for persistence or network transfer.
*/
#define INSTR_SETTABLE (-10)
#define INSTR_POP (-11)
#define INSTR_PUSHREF (-12)
/**
* Represents a single instruction that pushes a new value or works with existing ones.
*/
struct PackedInstr
{
s16 type; // LUA_T* or INSTR_*
u16 set_into; // set into table on stack
bool keep_ref; // is referenced later by INSTR_PUSHREF?
bool pop; // remove from stack?
union {
bool bdata; // boolean: value
lua_Number ndata; // number: value
struct {
u16 uidata1, uidata2; // table: narr, nrec
};
struct {
/*
SETTABLE: key index, value index
POP: indices to remove
otherwise w/ set_into: numeric key, -
*/
s32 sidata1, sidata2;
};
void *ptrdata; // userdata: implementation defined
s32 ref; // PUSHREF: index of referenced instr
};
/*
- string: value
- function: buffer
- w/ set_into: string key (no null bytes!)
- userdata: name in registry
*/
std::string sdata;
PackedInstr() : type(0), set_into(0), keep_ref(false), pop(false) {}
};
/**
* A packed value can be a primitive like a string or number but also a table
* including all of its contents. It is made up of a linear stream of
* 'instructions' that build the final value when executed.
*/
struct PackedValue
{
std::vector<PackedInstr> i;
// Indicates whether there are any userdata pointers that need to be deallocated
bool contains_userdata = false;
PackedValue() = default;
~PackedValue();
DISABLE_CLASS_COPY(PackedValue)
ALLOW_CLASS_MOVE(PackedValue)
};
/*
* Packing callback: Turns a Lua value at given index into a void*
*/
typedef void *(*PackInFunc)(lua_State *L, int idx);
/*
* Unpacking callback: Turns a void* back into the Lua value (left on top of stack)
*
* Note that this function must take ownership of the pointer, so make sure
* to free or keep the memory.
* `L` can be nullptr to indicate that data should just be discarded.
*/
typedef void (*PackOutFunc)(lua_State *L, void *ptr);
/*
* Register a packable type with the name of its metatable.
*
* Even though the callbacks are global this must be called for every Lua state
* that supports objects of this type.
* This function is thread-safe.
*/
void script_register_packer(lua_State *L, const char *regname,
PackInFunc fin, PackOutFunc fout);
// Pack a Lua value
PackedValue *script_pack(lua_State *L, int idx);
// Unpack a Lua value (left on top of stack)
// Note that this may modify the PackedValue, reusability is not guaranteed!
void script_unpack(lua_State *L, PackedValue *val);
// Dump contents of PackedValue to stdout for debugging
void script_dump_packed(const PackedValue *val);
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