org.luaj.vm2
Class LoadState

java.lang.Object
  org.luaj.vm2.LoadState

All Implemented Interfaces:

Globals.Undumper

public class LoadState
extends java.lang.Object
implements Globals.Undumper

Class to undump compiled lua bytecode into a Prototype instances.

The LoadState class implements Globals#Undumper which is used to undump a string of bytes that represent a lua binary file using either the C-based lua compiler, or luaj's DumpState#dump function.

The canonical method to load and execute code is done indirectly using the Globals:

 Globals globals = JsePlatform.standardGlobals();
 LuaValue chunk = globasl.load("print('hello, world')", "main.lua");
 chunk.call();
  

This should work regardless of which Globals.Compiler has been installed.

By default, when using JsePlatform or to construct globals, the LoadState is installed as the default Globals.undumper.

A lua binary file is created via DumpState#dump:

 Globals globals = JsePlatform.standardGlobals();
 Prototype p = globals.compilePrototype(new StringReader("print('hello, world')"), "main.lua");
 ByteArrayOutputStream o = new ByteArrayOutputStream();
 DumpState.dump(p, o, false);
 byte[] lua_binary_file_bytes = o.toByteArray();
  

The LoadState may be used directly to undump these bytes:

 Prototypep = LoadState.instance.undump(new ByteArrayInputStream(lua_binary_file_bytes), "main.lua");
 LuaClosure c = new LuaClosure(p, globals);
 c.call();
  

More commonly, the Globals.undumper may be used to undump them:

 Prototype p = globals.loadPrototype(new ByteArrayInputStream(lua_binary_file_bytes), "main.lua", "b");
 LuaClosure c = new LuaClosure(p, globals);
 c.call();
  

See Also:

LuaCompiler, LuaClosure, LuaFunction, Globals.compiler, LoadState#load(InputStream, String, LuaValue), LuaC, LuaJC

Field Summary

static java.lang.String	encoding The character encoding to use for file encoding.
static Globals.Undumper	instance Shared instance of Globals.Undumper to use loading prototypes from binary lua files
java.io.DataInputStream	is input stream from which we are loading
static byte[]	LUA_SIGNATURE Signature byte indicating the file is a compiled binary chunk
static int	LUA_TBOOLEAN
static int	LUA_TFUNCTION
static int	LUA_TINT
static int	LUA_TLIGHTUSERDATA
static int	LUA_TNIL
static int	LUA_TNONE
static int	LUA_TNUMBER
static int	LUA_TSTRING
static int	LUA_TTABLE
static int	LUA_TTHREAD
static int	LUA_TUSERDATA
static int	LUA_TVALUE
static int	LUAC_FORMAT for header of binary files -- this is the official format
static int	LUAC_HEADERSIZE size of header of binary files
static byte[]	LUAC_TAIL Data to catch conversion errors
static int	LUAC_VERSION for header of binary files -- this is Lua 5.2
static int	NUMBER_FORMAT_FLOATS_OR_DOUBLES format corresponding to non-number-patched lua, all numbers are floats or doubles
static int	NUMBER_FORMAT_INTS_ONLY format corresponding to non-number-patched lua, all numbers are ints
static int	NUMBER_FORMAT_NUM_PATCH_INT32 format corresponding to number-patched lua, all numbers are 32-bit (4 byte) ints
static java.lang.String	SOURCE_BINARY_STRING Name for compiled chunks

Method Summary

static java.lang.String	getSourceName(java.lang.String name) Construct a source name from a supplied chunk name
static void	install(Globals globals) Install this class as the standard Globals.Undumper for the supplied Globals
Prototype	loadFunction(LuaString p) Load a function prototype from the input stream
void	loadHeader() Load the lua chunk header values.
static LuaValue	longBitsToLuaNumber(long bits) Convert bits in a long value to a LuaValue.
Prototype	undump(java.io.InputStream stream, java.lang.String chunkname) Load input stream as a lua binary chunk if the first 4 bytes are the lua binary signature.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

instance

public static final Globals.Undumper instance

Shared instance of Globals.Undumper to use loading prototypes from binary lua files

NUMBER_FORMAT_FLOATS_OR_DOUBLES

public static final int NUMBER_FORMAT_FLOATS_OR_DOUBLES

format corresponding to non-number-patched lua, all numbers are floats or doubles

See Also:

Constant Field Values

NUMBER_FORMAT_INTS_ONLY

public static final int NUMBER_FORMAT_INTS_ONLY

format corresponding to non-number-patched lua, all numbers are ints

See Also:

Constant Field Values

NUMBER_FORMAT_NUM_PATCH_INT32

public static final int NUMBER_FORMAT_NUM_PATCH_INT32

format corresponding to number-patched lua, all numbers are 32-bit (4 byte) ints

See Also:

Constant Field Values

LUA_TINT

public static final int LUA_TINT

See Also:

Constant Field Values

LUA_TNONE

public static final int LUA_TNONE

See Also:

Constant Field Values

LUA_TNIL

public static final int LUA_TNIL

See Also:

Constant Field Values

LUA_TBOOLEAN

public static final int LUA_TBOOLEAN

See Also:

Constant Field Values

LUA_TLIGHTUSERDATA

public static final int LUA_TLIGHTUSERDATA

See Also:

Constant Field Values

LUA_TNUMBER

public static final int LUA_TNUMBER

See Also:

Constant Field Values

LUA_TSTRING

public static final int LUA_TSTRING

See Also:

Constant Field Values

LUA_TTABLE

public static final int LUA_TTABLE

See Also:

Constant Field Values

LUA_TFUNCTION

public static final int LUA_TFUNCTION

See Also:

Constant Field Values

LUA_TUSERDATA

public static final int LUA_TUSERDATA

See Also:

Constant Field Values

LUA_TTHREAD

public static final int LUA_TTHREAD

See Also:

Constant Field Values

LUA_TVALUE

public static final int LUA_TVALUE

See Also:

Constant Field Values

encoding

public static java.lang.String encoding

The character encoding to use for file encoding. Null means the default encoding

LUA_SIGNATURE

public static final byte[] LUA_SIGNATURE

Signature byte indicating the file is a compiled binary chunk

LUAC_TAIL

public static final byte[] LUAC_TAIL

Data to catch conversion errors

SOURCE_BINARY_STRING

public static final java.lang.String SOURCE_BINARY_STRING

Name for compiled chunks

See Also:

Constant Field Values

LUAC_VERSION

public static final int LUAC_VERSION

for header of binary files -- this is Lua 5.2

See Also:

Constant Field Values

LUAC_FORMAT

public static final int LUAC_FORMAT

for header of binary files -- this is the official format

See Also:

Constant Field Values

LUAC_HEADERSIZE

public static final int LUAC_HEADERSIZE

size of header of binary files

See Also:

Constant Field Values

is

public final java.io.DataInputStream is

input stream from which we are loading

Method Detail

install

public static void install(Globals globals)

Install this class as the standard Globals.Undumper for the supplied Globals

longBitsToLuaNumber

public static LuaValue longBitsToLuaNumber(long bits)

Convert bits in a long value to a LuaValue.

Parameters:

bits - long value containing the bits

Returns:

LuaInteger or LuaDouble whose value corresponds to the bits provided.

loadFunction

public Prototype loadFunction(LuaString p)
                       throws java.io.IOException

Load a function prototype from the input stream

Parameters:

p - name of the source

Returns:

Prototype instance that was loaded

Throws:

java.io.IOException

loadHeader

public void loadHeader()
                throws java.io.IOException

Load the lua chunk header values.

Throws:

java.io.IOException - if an i/o exception occurs.

undump

public Prototype undump(java.io.InputStream stream,
                        java.lang.String chunkname)
                 throws java.io.IOException

Load input stream as a lua binary chunk if the first 4 bytes are the lua binary signature.

Specified by:

undump in interface Globals.Undumper

Parameters:

stream - InputStream to read, after having read the first byte already

name - Name to apply to the loaded chunk

Returns:

Prototype that was loaded, or null if the first 4 bytes were not the lua signature.

Throws:

java.io.IOException - if an IOException occurs

getSourceName

public static java.lang.String getSourceName(java.lang.String name)

Construct a source name from a supplied chunk name

Parameters:

name - String name that appears in the chunk

Returns:

source file name