JezK
Edit File: core.cpython-39.pyc
a �#�_� � @ sx d dl mZ ddlmZmZmZ ddlmZm Z m Z G dd� de �Z G dd� de �Z G d d � d e �ZG d d � d e �ZG d d� de �ZG dd� de �ZG dd� de �ZG dd� de �ZG dd� de �ZG dd� de�ZG dd� de�ZG dd � d e�Zd d � Zd d � ZG d!d"� d"e�ZG d#d$� d$e�Z G d%d&� d&e�Z G d'd(� d(e�Z G d)d*� d*e�Z G d+d,� d,e�Z G d-d.� d.e�ZG d/d0� d0e�Z!G d1d2� d2e�Z"G d3d4� d4e�Z#G d5d6� d6e�Z$G d7d8� d8e�Z%G d9d:� d:e�Z&G d;d<� d<e�Z'G d=d>� d>e�Z(G d?d@� d@e�Z)G dAdB� dBe�Z*G dCdD� dDe�Z+G dEdF� dFe�Z,G dGdH� dHe�Z-G dIdJ� dJe�Z.e.dK�Z.G dLdM� dMe�Z/e/dK�Z/dKS )N� )�Struct� )�BytesIO�advance_iterator�bchr)� Container� ListContainer� LazyContainerc @ s e Zd Zg ZdS )�ConstructErrorN��__name__� __module__� __qualname__� __slots__� r r �;/usr/lib/python3.9/site-packages/elftools/construct/core.pyr s r c @ s e Zd Zg ZdS )� FieldErrorNr r r r r r s r c @ s e Zd Zg ZdS )� SizeofErrorNr r r r r r s r c @ s e Zd Zg ZdS )�AdaptationErrorNr r r r r r s r c @ s e Zd Zg ZdS )� ArrayErrorNr r r r r r s r c @ s e Zd Zg ZdS )� RangeErrorNr r r r r r s r c @ s e Zd Zg ZdS )� SwitchErrorNr r r r r r s r c @ s e Zd Zg ZdS )� SelectErrorNr r r r r r s r c @ s e Zd Zg ZdS )�TerminatorErrorNr r r r r r s r c @ s� e Zd ZdZdZdZdZdZddgZd,d d �Z d d � Z d d� Z dd� Z dd� Z dd� Zdd� Zdd� Zdd� Zdd � Zd d � Zd d � Zd!d"� Zd#d$� Zd%d&� Zd-d(d)�Zd*d+� Zd'S ).� Constructax The mother of all constructs. This object is generally not directly instantiated, and it does not directly implement parsing and building, so it is largely only of interest to subclass implementors. The external user API: * parse() * parse_stream() * build() * build_stream() * sizeof() Subclass authors should not override the external methods. Instead, another API is available: * _parse() * _build() * _sizeof() There is also a flag API: * _set_flag() * _clear_flag() * _inherit_flags() * _is_flag() And stateful copying: * __getstate__() * __setstate__() Attributes and Inheritance ========================== All constructs have a name and flags. The name is used for naming struct members and context dictionaries. Note that the name can either be a string, or None if the name is not needed. A single underscore ("_") is a reserved name, and so are names starting with a less-than character ("<"). The name should be descriptive, short, and valid as a Python identifier, although these rules are not enforced. The flags specify additional behavioral information about this construct. Flags are used by enclosing constructs to determine a proper course of action. Flags are inherited by default, from inner subconstructs to outer constructs. The enclosing construct may set new flags or clear existing ones, as necessary. For example, if FLAG_COPY_CONTEXT is set, repeaters will pass a copy of the context for each iteration, which is necessary for OnDemand parsing. r � � � �name�conflagsr c C sJ |d ur:t |�tur td|��|dks0|�d�r:td|��|| _|| _d S )Nz name must be a string or None�_�<z reserved name)�type�str� TypeError� startswith� ValueErrorr r )�selfr �flagsr r r �__init__] s zConstruct.__init__c C s d| j j| jf S )Nz%s(%r))� __class__r r �r' r r r �__repr__f s zConstruct.__repr__c C s | j |O _ dS )zv Set the given flag or flags. :param int flag: flag to set; may be OR'd combination of flags N�r �r' �flagr r r � _set_flagi s zConstruct._set_flagc C s | j | M _ dS )zz Clear the given flag or flags. :param int flag: flag to clear; may be OR'd combination of flags Nr- r. r r r � _clear_flagr s zConstruct._clear_flagc G s |D ]}| � |j� qdS )z0 Pull flags from subconstructs. N)r0 r )r' �subcons�scr r r �_inherit_flags{ s zConstruct._inherit_flagsc C s t | j|@ �S )z\ Check whether a given flag is set. :param int flag: flag to check )�boolr r. r r r �_is_flag� s zConstruct._is_flagc C sp i }t | d�r|�| j� g }| j}|durJt |d�rB|�|j� |j}q$|D ] }t | |�rNt| |�||< qN|S )zJ Obtain a dictionary representing this construct's state. �__dict__Nr )�hasattr�updater7 r* �extendr �__base__�getattr)r' �attrs�slots�cr r r r � __getstate__� s zConstruct.__getstate__c C s" |� � D ]\}}t| ||� qdS )z> Set this construct's state to a given state. N)�items�setattr)r' r= r �valuer r r � __setstate__� s zConstruct.__setstate__c C s t �| j�}|�| �� � |S )z returns a copy of this construct)�object�__new__r* rD r@ )r' Zself2r r r �__copy__� s zConstruct.__copy__c C s | � t|��S )z� Parse an in-memory buffer. Strings, buffers, memoryviews, and other complete buffers can be parsed with this method. )� parse_streamr )r' �datar r r �parse� s zConstruct.parsec C s | � |t� �S )z� Parse a stream. Files, pipes, sockets, and other streaming sources of data are handled by this method. )�_parser )r' �streamr r r rH � s zConstruct.parse_streamc C s t � �dS ��/ Override me in your subclass. N��NotImplementedError�r' rL �contextr r r rK � s zConstruct._parsec C s t � }| �||� |�� S )z, Build an object in memory. )r � build_stream�getvalue�r' �objrL r r r �build� s zConstruct.buildc C s | � ||t� � dS )z9 Build an object directly into a stream. N)�_buildr rU r r r rS � s zConstruct.build_streamc C s t � �dS rM rO �r' rV rL rR r r r rX � s zConstruct._buildNc C sL |du rt � }z | �|�W S tyF } zt|��W Y d}~n d}~0 0 dS )a� Calculate the size of this object, optionally using a context. Some constructs have no fixed size and can only know their size for a given hunk of data; these constructs will raise an error if they are not passed a context. :param ``Container`` context: contextual data :returns: int of the length of this construct :raises SizeofError: the size could not be determined N)r �_sizeof� Exceptionr )r' rR �er r r �sizeof� s zConstruct.sizeofc C s t d��dS )rN z Raw Constructs have no size!N�r �r' rR r r r rZ � s zConstruct._sizeof)r )N)r r r �__doc__�FLAG_COPY_CONTEXT� FLAG_DYNAMIC� FLAG_EMBEDZ FLAG_NESTINGr r) r, r0 r1 r4 r6 r@ rD rG rJ rH rK rW rS rX r] rZ r r r r r s. 6 r c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) � Subconstructz� Abstract subconstruct (wraps an inner construct, inheriting its name and flags). Parameters: * subcon - the construct to wrap �subconc C s t �| |j|j� || _d S �N)r r) r r re )r' re r r r r) s zSubconstruct.__init__c C s | j �||�S rf )re rK rQ r r r rK s zSubconstruct._parsec C s | j �|||� d S rf )re rX rY r r r rX s zSubconstruct._buildc C s | j �|�S rf )re rZ r_ r r r rZ s zSubconstruct._sizeofN� r r r r` r r) rK rX rZ r r r r rd � s rd c @ s4 e Zd ZdZg Zdd� Zdd� Zdd� Zdd � Zd S ) �Adapterz� Abstract adapter: calls _decode for parsing and _encode for building. Parameters: * subcon - the construct to wrap c C s | � | j�||�|�S rf )�_decodere rK rQ r r r rK s zAdapter._parsec C s | j �| �||�||� d S rf )re rX �_encoderY r r r rX s zAdapter._buildc C s t � �d S rf rO �r' rV rR r r r ri s zAdapter._decodec C s t � �d S rf rO rk r r r rj s zAdapter._encodeN) r r r r` r rK rX ri rj r r r r rh s rh c C s@ |dk rt d|��| �|�}t|�|kr<td|t|�f ��|S �Nr zlength must be >= 0�expected %d, found %d)r& �read�lenr �rL �lengthrI r r r � _read_stream s rr c C s@ |dk rt d|��t|�|kr2td|t|�f ��| �|� d S rl )r& ro r �writerp r r r � _write_stream( s rt c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) � StaticFieldzw A fixed-size byte field. :param str name: field name :param int length: number of bytes in the field rq c C s t �| |� || _d S rf )r r) rq )r' r rq r r r r) 8 s zStaticField.__init__c C s t || j�S rf )rr rq rQ r r r rK ; s zStaticField._parsec C s t || j|� d S rf )rt rq rY r r r rX = s zStaticField._buildc C s | j S rf )rq r_ r r r rZ ? s zStaticField._sizeofNrg r r r r ru / s ru c @ s> e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd d � Z d S )� FormatFielda4 A field that uses ``struct`` to pack and unpack data. See ``struct`` documentation for instructions on crafting format strings. :param str name: name of the field :param str endianness: format endianness string; one of "<", ">", or "=" :param str format: a single format character �packerc C sJ |dvrt d|��t|�dkr&t d��t|| �| _t�| || jj� d S )N)�>r! �=z%endianity must be be '=', '<', or '>'r z)must specify one and only one format char)r& ro �Packerrw ru r) �size)r' r Z endianity�formatr r r r) N s � zFormatField.__init__c C s t �| �}|d j|d< |S �Nrw )ru r@ r| �r' r= r r r r@ V s zFormatField.__getstate__c C s t |d �|d< t�| |�S r} )rz ru rD r~ r r r rD Z s zFormatField.__setstate__c C sL z| j �t|| j��d W S tyF } zt|��W Y d }~n d }~0 0 d S �Nr )rw �unpackrr rq r[ r )r' rL rR �exr r r rK ] s zFormatField._parsec C sL zt || j| j�|�� W n, tyF } zt|��W Y d }~n d }~0 0 d S rf )rt rq rw �packr[ r )r' rV rL rR r� r r r rX b s zFormatField._buildN) r r r r` r r) r@ rD rK rX r r r r rv B s rv c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) � MetaFielda A variable-length field. The length is obtained at runtime from a function. :param str name: name of the field :param callable lengthfunc: callable that takes a context and returns length as an int >>> foo = Struct("foo", ... Byte("length"), ... MetaField("data", lambda ctx: ctx["length"]) ... ) >>> foo.parse("\x03ABC") Container(data = 'ABC', length = 3) >>> foo.parse("\x04ABCD") Container(data = 'ABCD', length = 4) � lengthfuncc C s" t �| |� || _| �| j� d S rf )r r) r� r0 rb )r' r r� r r r r) | s zMetaField.__init__c C s t || �|��S rf )rr r� rQ r r r rK � s zMetaField._parsec C s t || �|�|� d S rf )rt r� rY r r r rX � s zMetaField._buildc C s | � |�S rf )r� r_ r r r rZ � s zMetaField._sizeofNrg r r r r r� h s r� c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) � MetaArraya� An array (repeater) of a meta-count. The array will iterate exactly `countfunc()` times. Will raise ArrayError if less elements are found. See also Array, Range and RepeatUntil. Parameters: * countfunc - a function that takes the context as a parameter and returns the number of elements of the array (count) * subcon - the subcon to repeat `countfunc()` times Example: MetaArray(lambda ctx: 5, UBInt8("foo")) � countfuncc C s. t �| |� || _| �| j� | �| j� d S rf )rd r) r� r1 ra r0 rb )r' r� re r r r r) � s zMetaArray.__init__c C s� t � }d}| �|�}zd| jj| j@ rP||k rv|�| j�||�� �� |d7 }q$n&||k rv|�| j�||�� |d7 }qPW n6 ty� } z t d||f |��W Y d }~n d }~0 0 |S )Nr r rm ) r r� re r ra �appendrK rG r r )r' rL rR rV r? �countr� r r r rK � s (zMetaArray._parsec C sv | � |�}t|�|kr*td|t|�f ��| jj| j@ rX|D ]}| j�|||�� � q<n|D ]}| j�|||� q\d S )Nrm )r� ro r re r ra rX rG )r' rV rL rR r� �subobjr r r rX � s zMetaArray._buildc C s | j �|�| �|� S rf )re rZ r� r_ r r r rZ � s zMetaArray._sizeofNrg r r r r r� � s r� c @ s8 e Zd ZdZddgZdd� Zdd� Zdd � Zd d � Zd S ) �Rangea� A range-array. The subcon will iterate between `mincount` to `maxcount` times. If less than `mincount` elements are found, raises RangeError. See also GreedyRange and OptionalGreedyRange. The general-case repeater. Repeats the given unit for at least mincount times, and up to maxcount times. If an exception occurs (EOF, validation error), the repeater exits. If less than mincount units have been successfully parsed, a RangeError is raised. .. note:: This object requires a seekable stream for parsing. :param int mincount: the minimal count :param int maxcount: the maximal count :param Construct subcon: the subcon to repeat >>> c = Range(3, 7, UBInt8("foo")) >>> c.parse("\x01\x02") Traceback (most recent call last): ... construct.core.RangeError: expected 3..7, found 2 >>> c.parse("\x01\x02\x03") [1, 2, 3] >>> c.parse("\x01\x02\x03\x04\x05\x06") [1, 2, 3, 4, 5, 6] >>> c.parse("\x01\x02\x03\x04\x05\x06\x07") [1, 2, 3, 4, 5, 6, 7] >>> c.parse("\x01\x02\x03\x04\x05\x06\x07\x08\x09") [1, 2, 3, 4, 5, 6, 7] >>> c.build([1,2]) Traceback (most recent call last): ... construct.core.RangeError: expected 3..7, found 2 >>> c.build([1,2,3,4]) '\x01\x02\x03\x04' >>> c.build([1,2,3,4,5,6,7,8]) Traceback (most recent call last): ... construct.core.RangeError: expected 3..7, found 8 �mincount�maxcoutc C s4 t �| |� || _|| _| �| j� | �| j� d S rf )rd r) r� r� r1 ra r0 rb )r' r� r� re r r r r) � s zRange.__init__c C s� t � }d}zx| jj| j@ rP|| jk r�|�� }|�| j�||�� �� |d7 }qn0|| jk r�|�� }|�| j�||�� |d7 }qPW nP t y� } z8|| j k r�t d| j | j|f |��|� |� W Y d }~n d }~0 0 |S )Nr r �expected %d to %d, found %d) r re r ra r� �tellr� rK rG r r� r �seek)r' rL rR rV r? �posr� r r r rK � s* �� z Range._parsec C s t |�| jk s t |�| jkr6td| j| jt |�f ��d}z�| jj| j@ r�|D ]2}t|t�rdt |�}| j� |||� � � |d7 }qNn4|D ].}t|t�r�t |�}| j� |||� |d7 }q�W nL t �y } z2|| jk r�td| j| jt |�f |��W Y d }~n d }~0 0 d S )Nr� r r ) ro r� r� r re r ra � isinstance�bytesr rX rG r )r' rV rL rR Zcntr� r� r r r rX s0 � ��z Range._buildc C s t d��d S �Nzcan't calculate sizer^ r_ r r r rZ s z Range._sizeofNrg r r r r r� � s *r� c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) � RepeatUntila� An array that repeats until the predicate indicates it to stop. Note that the last element (which caused the repeat to exit) is included in the return value. Parameters: * predicate - a predicate function that takes (obj, context) and returns True if the stop-condition is met, or False to continue. * subcon - the subcon to repeat. Example: # will read chars until b (inclusive) RepeatUntil(lambda obj, ctx: obj == b" ", Field("chars", 1) ) � predicatec C s. t �| |� || _| �| j� | �| j� d S rf )rd r) r� r1 ra r0 rb )r' r� re r r r r) - s zRepeatUntil.__init__c C s� g }zh| j j| j@ rB| j �||�� �}|�|� | �||�rqjqn(| j �||�}|�|� | �||�rBqjqBW n. ty� } ztd|��W Y d }~n d }~0 0 |S )N�missing terminator) re r ra rK rG r� r� r r )r' rL rR rV r� r� r r r rK 2 s zRepeatUntil._parsec C s� d}| j j| j@ rF|D ],}| j �|||�� � | �||�rd} q�qn:|D ]4}t|�}| j �|||�� � | �||�rJd} q�qJ|s�td��d S )NFTr� )re r ra rX rG r� r r )r' rV rL rR Z terminatedr� r r r rX D s zRepeatUntil._buildc C s t d��d S r� r^ r_ r r r rZ U s zRepeatUntil._sizeofNrg r r r r r� s r� c @ s8 e Zd ZdZddgZdd� Zdd� Zdd � Zd d � Zd S ) r a� A sequence of named constructs, similar to structs in C. The elements are parsed and built in the order they are defined. See also Embedded. Parameters: * name - the name of the structure * subcons - a sequence of subconstructs that make up this structure. * nested - a keyword-only argument that indicates whether this struct creates a nested context. The default is True. This parameter is considered "advanced usage", and may be removed in the future. Example: Struct("foo", UBInt8("first_element"), UBInt16("second_element"), Padding(2), UBInt8("third_element"), ) r2 �nestedc O sH |� dd�| _|r td|��t�| |� || _| j|� | �| j� d S )Nr� Tz.the only keyword argument accepted is 'nested') �popr� r$ r r) r2 r4 r1 rc )r' r r2 �kwr r r r) r s zStruct.__init__c C s� d|v r|d }|d= nt � }| jr.t |d�}| jD ]P}|j| j@ rZ||d< |�||� q4|�||�}|jd ur4|||j< |||j< q4|S �Nz<obj>�r )r r� r2 r rc rK r �r' rL rR rV r3 r� r r r rK z s z Struct._parsec C s~ d|v r|d= n| j r t|d�}| jD ]R}|j| j@ rDd|d< |}n&|jd u rTd }nt||j�}|||j< |�|||� q&d S �Nz <unnested>r� T)r� r r2 r rc r r< rX )r' rV rL rR r3 r� r r r rX � s z Struct._buildc s( | j rt� d�� t� fdd�| jD ��S )Nr� c 3 s | ]}|� � �V qd S rf �rZ ��.0r3 �rR r r � <genexpr>� � z!Struct._sizeof.<locals>.<genexpr>)r� r �sumr2 r_ r r� r rZ � s zStruct._sizeofNrg r r r r r \ s r c @ s$ e Zd ZdZg Zdd� Zdd� ZdS )�Sequencea A sequence of unnamed constructs. The elements are parsed and built in the order they are defined. See also Embedded. Parameters: * name - the name of the structure * subcons - a sequence of subconstructs that make up this structure. * nested - a keyword-only argument that indicates whether this struct creates a nested context. The default is True. This parameter is considered "advanced usage", and may be removed in the future. Example: Sequence("foo", UBInt8("first_element"), UBInt16("second_element"), Padding(2), UBInt8("third_element"), ) c C s� d|v r|d }|d= nt � }| jr.t|d�}| jD ]P}|j| j@ rZ||d< |�||� q4|�||�}|jd ur4|�|� |||j< q4|S r� ) r r� r r2 r rc rK r r� r� r r r rK � s zSequence._parsec C s� d|v r|d= n| j r t|d�}t|�}| jD ]N}|j| j@ rLd|d< |}n"|jd u r\d }nt|�}|||j< |�|||� q.d S r� ) r� r �iterr2 r rc r r rX )r' rV rL rR Zobjiterr3 r� r r r rX � s zSequence._buildN)r r r r` r rK rX r r r r r� � s r� c @ s8 e Zd ZdZddgZdd� Zdd� Zdd � Zd d � Zd S ) �Uniona� a set of overlapping fields (like unions in C). when parsing, all fields read the same data; when building, only the first subcon (called "master") is used. Parameters: * name - the name of the union * master - the master subcon, i.e., the subcon used for building and calculating the total size * subcons - additional subcons Example: Union("what_are_four_bytes", UBInt32("one_dword"), Struct("two_words", UBInt16("first"), UBInt16("second")), Struct("four_bytes", UBInt8("a"), UBInt8("b"), UBInt8("c"), UBInt8("d") ), ) �parser�builderc s^ t �| |� dd� |D �}|�td � fdd��� t|t� dd�g|�R � | _t|� �| _d S )Nc S s g | ] }t |��qS r )�Peekr� r r r � <listcomp>� r� z"Union.__init__.<locals>.<listcomp>c s � � | �S rf r� )�ctx��masterr r �<lambda>� r� z Union.__init__.<locals>.<lambda>T)� perform_build)r r) r� r� r r� r� r� )r' r r� r2 r� �argsr r� r r) � s zUnion.__init__c C s | j �||�S rf )r� rK rQ r r r rK � s z Union._parsec C s | j �|||�S rf )r� rX rY r r r rX � s z Union._buildc C s | j �|�S rf )r� rZ r_ r r r rZ � s z Union._sizeofNrg r r r r r� � s r� c @ sV e Zd ZdZG dd� de�Zed�Zg d�Zedfdd�Zd d � Zd d � Z d d� Z dS )�Switchah A conditional branch. Switch will choose the case to follow based on the return value of keyfunc. If no case is matched, and no default value is given, SwitchError will be raised. See also Pass. Parameters: * name - the name of the construct * keyfunc - a function that takes the context and returns a key, which will ne used to choose the relevant case. * cases - a dictionary mapping keys to constructs. the keys can be any values that may be returned by keyfunc. * default - a default value to use when the key is not found in the cases. if not supplied, an exception will be raised when the key is not found. You can use the builtin construct Pass for 'do-nothing'. * include_key - whether or not to include the key in the return value of parsing. defualt is False. Example: Struct("foo", UBInt8("type"), Switch("value", lambda ctx: ctx.type, { 1 : UBInt8("spam"), 2 : UBInt16("spam"), 3 : UBInt32("spam"), 4 : UBInt64("spam"), } ), ) c @ s$ e Zd Zdd� Zdd� Zdd� ZdS )zSwitch.NoDefaultc C s t d��d S �Nzno default case defined�r rQ r r r rK # s zSwitch.NoDefault._parsec C s t d��d S r� r� rY r r r rX % s zSwitch.NoDefault._buildc C s t d��d S r� r� r_ r r r rZ ' s zSwitch.NoDefault._sizeofN)r r r rK rX rZ r r r r � NoDefault" s r� zNo default value specified)r2 �keyfunc�cases�default� include_keyFc C sP t �| |� | j|�� � || _|| _|| _|| _| j|�� � | �| j � d S rf ) r r) r4 �valuesr� r� r� r� r0 rb )r' r r� r� r� r� r r r r) - s zSwitch.__init__c C s8 | � |�}| j�|| j��||�}| jr0||fS |S d S rf )r� r� �getr� rK r� )r' rL rR �keyrV r r r rK 7 s z Switch._parsec C s< | j r|\}}n | �|�}| j�|| j�}|�|||� d S rf )r� r� r� r� r� rX )r' rV rL rR r� �caser r r rX > s z Switch._buildc C s | j �| �|�| j�}|�|�S rf )r� r� r� r� rZ )r' rR r� r r r rZ E s zSwitch._sizeofN) r r r r` r r� r r) rK rX rZ r r r r r� s � r� c @ s8 e Zd ZdZddgZdd� Zdd� Zdd � Zd d � Zd S ) �SelectaL Selects the first matching subconstruct. It will literally try each of the subconstructs, until one matches. Notes: * requires a seekable stream. Parameters: * name - the name of the construct * subcons - the subcons to try (order-sensitive) * include_name - a keyword only argument, indicating whether to include the name of the selected subcon in the return value of parsing. default is false. Example: Select("foo", UBInt64("large"), UBInt32("medium"), UBInt16("small"), UBInt8("tiny"), ) r2 � include_namec O sL |� dd�}|rtd|��t�| |� || _|| _| j|� | �| j� d S )Nr� Fz4the only keyword argument accepted is 'include_name') r� r$ r r) r2 r� r4 r0 rb )r' r r2 r� r� r r r r) a s � zSelect.__init__c C s| | j D ]h}|�� }|�� }z|�||�}W n tyF |�|� Y q0 |�|� | jrf|j|f S | S qt d��d S �Nzno subconstruct matched) r2 r� rG rK r r� � __update__r� r r )r' rL rR r3 r� �context2rV r r r rK k s z Select._parsec C s� | j r:|\}}| jD ]"}|j|kr|�|||� d S qn^| jD ]V}t� }|�� }z|�|||� W n tyv Y q@0 |�|� |�|� � � d S q@t d|��d S r� ) r� r2 r rX r rG r[ r� rs rT r )r' rV rL rR r r3 �stream2r� r r r rX z s" z Select._buildc C s t d��d S r� r^ r_ r r r rZ � s zSelect._sizeofNrg r r r r r� I s r� c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) �Pointeraj Changes the stream position to a given offset, where the construction should take place, and restores the stream position when finished. See also Anchor, OnDemand and OnDemandPointer. Notes: * requires a seekable stream. Parameters: * offsetfunc: a function that takes the context and returns an absolute stream position, where the construction would take place * subcon - the subcon to use at `offsetfunc()` Example: Struct("foo", UBInt32("spam_pointer"), Pointer(lambda ctx: ctx.spam_pointer, Array(5, UBInt8("spam")) ) ) � offsetfuncc C s t �| |� || _d S rf )rd r) r� )r' r� re r r r r) � s zPointer.__init__c C s8 | � |�}|�� }|�|� | j�||�}|�|� |S rf )r� r� r� re rK )r' rL rR �newpos�origposrV r r r rK � s zPointer._parsec C s: | � |�}|�� }|�|� | j�|||� |�|� d S rf )r� r� r� re rX )r' rV rL rR r� r� r r r rX � s zPointer._buildc C s dS r r r_ r r r rZ � s zPointer._sizeofNrg r r r r r� � s r� c @ s8 e Zd ZdZdgZd dd�Zdd� Zdd � Zd d � Zd S )r� a� Peeks at the stream: parses without changing the stream position. See also Union. If the end of the stream is reached when peeking, returns None. Notes: * requires a seekable stream. Parameters: * subcon - the subcon to peek at * perform_build - whether or not to perform building. by default this parameter is set to False, meaning building is a no-op. Example: Peek(UBInt8("foo")) r� Fc C s t �| |� || _d S rf )rd r) r� )r' re r� r r r r) � s z Peek.__init__c C sX |� � }z>z | j�||�W W |�|� S ty8 Y n0 W |�|� n |�|� 0 d S rf )r� re rK r� r )r' rL rR r� r r r rK � s � z Peek._parsec C s | j r| j�|||� d S rf )r� re rX rY r r r rX � s z Peek._buildc C s dS r r r_ r r r rZ � s z Peek._sizeofN)Frg r r r r r� � s r� c @ s2 e Zd ZdZddgZd dd�Zdd� Zd d � Zd S ) �OnDemanda� Allows for on-demand (lazy) parsing. When parsing, it will return a LazyContainer that represents a pointer to the data, but does not actually parses it from stream until it's "demanded". By accessing the 'value' property of LazyContainers, you will demand the data from the stream. The data will be parsed and cached for later use. You can use the 'has_value' property to know whether the data has already been demanded. See also OnDemandPointer. Notes: * requires a seekable stream. Parameters: * subcon - * advance_stream - whether or not to advance the stream position. by default this is True, but if subcon is a pointer, this should be False. * force_build - whether or not to force build. If set to False, and the LazyContainer has not been demaned, building is a no-op. Example: OnDemand(Array(10000, UBInt8("foo")) �advance_stream� force_buildTc C s t �| |� || _|| _d S rf )rd r) r� r� )r' re r� r� r r r r) � s zOnDemand.__init__c C s2 t | j||�� |�}| jr.|�| j�|�d� |S �Nr )r re r� r� r� rZ )r' rL rR rV r r r rK � s zOnDemand._parsec C sZ t |t�s | j�|||� n:| js(|jr<| j�|j||� n| jrV|�| j� |�d� d S r� ) r� r re rX r� Z has_valuerC r� r� rZ rY r r r rX s zOnDemand._buildN)TT)r r r r` r r) rK rX r r r r r� � s r� c @ s8 e Zd ZdZg d�Zdd� Zdd� Zdd� Zd d � Zd S ) �Buffereda Creates an in-memory buffered stream, which can undergo encoding and decoding prior to being passed on to the subconstruct. See also Bitwise. Note: * Do not use pointers inside Buffered Parameters: * subcon - the subcon which will operate on the buffer * encoder - a function that takes a string and returns an encoded string (used after building) * decoder - a function that takes a string and returns a decoded string (used before parsing) * resizer - a function that takes the size of the subcon and "adjusts" or "resizes" it according to the encoding/decoding process. Example: Buffered(BitField("foo", 16), encoder = decode_bin, decoder = encode_bin, resizer = lambda size: size / 8, ) )�encoder�decoder�resizerc C s" t �| |� || _|| _|| _d S rf )rd r) r� r� r� )r' re r� r� r� r r r r) & s zBuffered.__init__c C s, t || �|��}t| �|��}| j�||�S rf )rr rZ r r� re rK )r' rL rR rI r� r r r rK + s zBuffered._parsec C sT | � |�}t� }| j�|||� | �|�� �}t|�|ks>J �t|| � |�|� d S rf )rZ r re rX r� rT ro rt )r' rV rL rR r{ r� rI r r r rX / s zBuffered._buildc C s | � | j�|��S rf �r� re rZ r_ r r r rZ 6 s zBuffered._sizeofNrg r r r r r� s r� c @ s8 e Zd ZdZg d�Zdd� Zdd� Zdd� Zd d � Zd S ) �Restreama" Wraps the stream with a read-wrapper (for parsing) or a write-wrapper (for building). The stream wrapper can buffer the data internally, reading it from- or writing it to the underlying stream as needed. For example, BitStreamReader reads whole bytes from the underlying stream, but returns them as individual bits. See also Bitwise. When the parsing or building is done, the stream's close method will be invoked. It can perform any finalization needed for the stream wrapper, but it must not close the underlying stream. Note: * Do not use pointers inside Restream Parameters: * subcon - the subcon * stream_reader - the read-wrapper * stream_writer - the write wrapper * resizer - a function that takes the size of the subcon and "adjusts" or "resizes" it according to the encoding/decoding process. Example: Restream(BitField("foo", 16), stream_reader = BitStreamReader, stream_writer = BitStreamWriter, resizer = lambda size: size / 8, ) )� stream_reader� stream_writerr� c C s" t �| |� || _|| _|| _d S rf )rd r) r� r� r� )r' re r� r� r� r r r r) X s zRestream.__init__c C s$ | � |�}| j�||�}|�� |S rf )r� re rK �close)r' rL rR r� rV r r r rK ] s zRestream._parsec C s& | � |�}| j�|||� |�� d S rf )r� re rX r� )r' rV rL rR r� r r r rX b s zRestream._buildc C s | � | j�|��S rf r� r_ r r r rZ f s zRestream._sizeofNrg r r r r r� 9 s r� c @ s e Zd ZdZg Zddd�ZdS )�Reconfigaj Reconfigures a subconstruct. Reconfig can be used to change the name and set and clear flags of the inner subcon. Parameters: * name - the new name * subcon - the subcon to reconfigure * setflags - the flags to set (default is 0) * clearflags - the flags to clear (default is 0) Example: Reconfig("foo", UBInt8("bar")) r c C s. t �| ||j� || _| �|� | �|� d S rf )r r) r re r0 r1 )r' r re ZsetflagsZ clearflagsr r r r) | s zReconfig.__init__N)r r )r r r r` r r) r r r r r� m s r� c @ s, e Zd ZdZg Zdd� Zdd� Zdd� ZdS ) �AnchoraM Returns the "anchor" (stream position) at the point where it's inserted. Useful for adjusting relative offsets to absolute positions, or to measure sizes of constructs. absolute pointer = anchor + relative offset size = anchor_after - anchor_before See also Pointer. Notes: * requires a seekable stream. Parameters: * name - the name of the anchor Example: Struct("foo", Anchor("base"), UBInt8("relative_offset"), Pointer(lambda ctx: ctx.relative_offset + ctx.base, UBInt8("data") ) ) c C s |� � S rf )r� rQ r r r rK � s z Anchor._parsec C s |� � || j< d S rf )r� r rY r r r rX � s z Anchor._buildc C s dS r r r_ r r r rZ � s zAnchor._sizeofN�r r r r` r rK rX rZ r r r r r� � s r� c @ s6 e Zd ZdZdgZdd� Zdd� Zdd� Zd d � Zd S ) �Valuea8 A computed value. Parameters: * name - the name of the value * func - a function that takes the context and return the computed value Example: Struct("foo", UBInt8("width"), UBInt8("height"), Value("total_pixels", lambda ctx: ctx.width * ctx.height), ) �funcc C s" t �| |� || _| �| j� d S rf )r r) r� r0 rb )r' r r� r r r r) � s zValue.__init__c C s | � |�S rf )r� rQ r r r rK � s z Value._parsec C s | � |�|| j< d S rf )r� r rY r r r rX � s z Value._buildc C s dS r r r_ r r r rZ � s z Value._sizeofNrg r r r r r� � s r� c @ s8 e Zd ZdZddgZdd� Zdd� Zdd � Zd d � Zd S ) � LazyBounda Lazily bound construct, useful for constructs that need to make cyclic references (linked-lists, expression trees, etc.). Parameters: Example: foo = Struct("foo", UBInt8("bar"), LazyBound("next", lambda: foo), ) �bindfunc�boundc C s t �| |� d | _|| _d S rf )r r) r� r� )r' r r� r r r r) � s zLazyBound.__init__c C s" | j d u r| �� | _ | j �||�S rf )r� r� rK rQ r r r rK � s zLazyBound._parsec C s( | j d u r| �� | _ | j �|||� d S rf )r� r� rX rY r r r rX � s zLazyBound._buildc C s | j d u r| �� | _ | j �|�S rf )r� r� rZ r_ r r r rZ � s zLazyBound._sizeofNrg r r r r r� � s r� c @ s4 e Zd ZdZg Zdd� Zdd� Zdd� Zdd � Zd S ) �Passa A do-nothing construct, useful as the default case for Switch, or to indicate Enums. See also Switch and Enum. Notes: * this construct is a singleton. do not try to instatiate it, as it will not work... Example: Pass c C s d S rf r rQ r r r rK s z Pass._parsec C s |d u s J �d S rf r rY r r r rX s z Pass._buildc C s dS r r r_ r r r rZ s z Pass._sizeofc C s | j jS rf )r* r r+ r r r � __reduce__ s zPass.__reduce__N) r r r r` r rK rX rZ r� r r r r r� s r� Nc @ s, e Zd ZdZg Zdd� Zdd� Zdd� ZdS ) � Terminatorao Asserts the end of the stream has been reached at the point it's placed. You can use this to ensure no more unparsed data follows. Notes: * this construct is only meaningful for parsing. for building, it's a no-op. * this construct is a singleton. do not try to instatiate it, as it will not work... Example: Terminator c C s |� d�rtd��d S )Nr zexpected end of stream)rn r rQ r r r rK ' s zTerminator._parsec C s |d u s J �d S rf r rY r r r rX * s zTerminator._buildc C s dS r r r_ r r r rZ , s zTerminator._sizeofNr� r r r r r� s r� )0�structr rz Z lib.py3compatr r r �libr r r r[ r r r r r r r r r rE r rd rh rr rt ru rv r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r r r r �<module> sR Y_AD9)GL*#*-4 >