mirror of https://github.com/minetest/minetest.git
130 lines
3.8 KiB
C++
130 lines
3.8 KiB
C++
/*
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Minetest
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Copyright (C) 2022 sfan5 <sfan5@live.de>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#pragma once
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#include <string>
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#include <vector>
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#include "irrlichttypes.h"
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#include "util/basic_macros.h"
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extern "C" {
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#include <lua.h>
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}
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/*
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This file defines an in-memory representation of Lua objects including
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support for functions and userdata. It it used to move data between Lua
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states and cannot be used for persistence or network transfer.
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*/
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#define INSTR_SETTABLE (-10)
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#define INSTR_POP (-11)
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#define INSTR_PUSHREF (-12)
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#define INSTR_SETMETATABLE (-13)
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/**
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* Represents a single instruction that pushes a new value or operates with existing ones.
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*/
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struct PackedInstr
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{
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s16 type; // LUA_T* or INSTR_*
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u16 set_into; // set into table on stack
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bool keep_ref; // referenced later by INSTR_PUSHREF?
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bool pop; // remove from stack?
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// Note: the remaining members are named by type, not usage
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union {
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bool bdata; // boolean: value
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lua_Number ndata; // number: value
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struct {
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u16 uidata1, uidata2; // table: narr | nrec
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};
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struct {
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/*
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SETTABLE: key index | value index
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POP: indices to remove
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PUSHREF: index of referenced instr | unused
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otherwise w/ set_into: numeric key | unused
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*/
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s32 sidata1, sidata2;
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};
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void *ptrdata; // userdata: implementation defined
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};
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/*
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- string: value
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- function: buffer
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- w/ set_into: string key (no null bytes!)
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- userdata: name in registry
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- INSTR_SETMETATABLE: name of the metatable
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*/
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std::string sdata;
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PackedInstr() : type(0), set_into(0), keep_ref(false), pop(false) {}
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};
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/**
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* A packed value can be a primitive like a string or number but also a table
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* including all of its contents. It is made up of a linear stream of
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* instructions that build the final value when executed.
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*/
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struct PackedValue
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{
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std::vector<PackedInstr> i;
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// Indicates whether there are any userdata pointers that need to be deallocated
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bool contains_userdata = false;
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PackedValue() = default;
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~PackedValue();
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DISABLE_CLASS_COPY(PackedValue)
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ALLOW_CLASS_MOVE(PackedValue)
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};
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/*
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* Packing callback: Turns a Lua value at given index into a void*
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*/
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typedef void *(*PackInFunc)(lua_State *L, int idx);
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/*
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* Unpacking callback: Turns a void* back into the Lua value (left on top of stack)
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*
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* Note that this function must take ownership of the pointer, so make sure
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* to free or keep the memory.
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* `L` can be nullptr to indicate that data should just be discarded.
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*/
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typedef void (*PackOutFunc)(lua_State *L, void *ptr);
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/*
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* Register a packable type with the name of its metatable.
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*
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* Even though the callbacks are global this must be called for every Lua state
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* that supports objects of this type.
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* This function is thread-safe.
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*/
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void script_register_packer(lua_State *L, const char *regname,
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PackInFunc fin, PackOutFunc fout);
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// Pack a Lua value
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PackedValue *script_pack(lua_State *L, int idx);
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// Unpack a Lua value (left on top of stack)
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// Note that this may modify the PackedValue, reusability is not guaranteed!
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void script_unpack(lua_State *L, PackedValue *val);
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// Dump contents of PackedValue to stdout for debugging
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void script_dump_packed(const PackedValue *val);
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