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Note that the helper functions in lib module can raise standard ValueError (but parsing classes are not allowed to). � Nc s: || _ |d u r t� �|� nd�|�| }t� �|� d S )NzError in path {} )�path�super�__init__�format)�self�messager �� __class__� �~/root/rpmbuild/BUILDROOT/imh-python39-modules-3.9.7-92.el8.x86_64/opt/imh-python/lib/python3.9/site-packages/construct/core.pyr s zConstructError.__init__)r N��__name__� __module__� __qualname__�__doc__r � __classcell__r r r r r s r c @ s e Zd ZdZdS )� SizeofErrorar Parsing classes sizeof() methods are only allowed to either return an integer or raise SizeofError instead. Note that this exception can mean the parsing class cannot be measured apriori in principle, however it can also mean that it just cannot be measured in these particular circumstances (eg. there is a key missing in the context dictionary at this time). N�r r r r r r r r r s r c @ s e Zd ZdZdS )�AdaptationError� Currently not used. Nr r r r r r s r c @ s e Zd ZdZdS )�ValidationErrorz� Validator ExprValidator derived parsing classes can raise this exception: OneOf NoneOf. It can mean that the parse or build value is or is not one of specified values. Nr r r r r r " s r c @ s e Zd ZdZdS )� StreamErrora� Almost all parsing classes can raise this exception: it can mean a variety of things. Maybe requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, could not write all bytes, stream is not seekable, stream is not tellable, etc. Note that there are a few parsing classes that do not use the stream to compute output and therefore do not raise this exception. Nr r r r r r ' s r c @ s e Zd ZdZdS )�FormatFieldErrorz� Only one parsing class can raise this exception: FormatField. It can either mean the format string is invalid or the value is not valid for provided format string. See standard struct module for what is acceptable. Nr r r r r r , s r c @ s e Zd ZdZdS )� IntegerErrora/ Only some numeric parsing classes can raise this exception: BytesInteger BitsInteger VarInt ZigZag. It can mean either the length parameter is invalid, the value is not an integer, the value is negative or too low or too high for given parameters, or the selected endianness cannot be applied. Nr r r r r r 1 s r c @ s e Zd ZdZdS )� StringErrora� Almost all parsing classes can raise this exception: It can mean a unicode string was passed instead of bytes, or a bytes was passed instead of a unicode string. Also some classes can raise it explicitly: PascalString CString GreedyString. It can mean no encoding or invalid encoding was selected. Note that currently, if the data cannot be encoded decoded given selected encoding then UnicodeEncodeError UnicodeDecodeError are raised, which are not rooted at ConstructError. Nr r r r r r 6 s r c @ s e Zd ZdZdS )� MappingErrorz� Few parsing classes can raise this exception: Enum FlagsEnum Mapping. It can mean the build value is not recognized and therefore cannot be mapped onto bytes. Nr r r r r r ; s r c @ s e Zd ZdZdS )� RangeErrorz� Few parsing classes can raise this exception: Array PrefixedArray LazyArray. It can mean the count parameter is invalid, or the build object has too little or too many elements. Nr r r r r r @ s r c @ s e Zd ZdZdS )� RepeatErrorz� Only one parsing class can raise this exception: RepeatUntil. It can mean none of the elements in build object passed the given predicate. Nr r r r r r E s r c @ s e Zd ZdZdS )� ConstErrorz� Only one parsing class can raise this exception: Const. It can mean the wrong data was parsed, or wrong object was built from. Nr r r r r r! J s r! c @ s e Zd ZdZdS )�IndexFieldErrorz� Only one parsing class can raise this exception: Index. It can mean the class was not nested in an array parsing class properly and therefore cannot access the _index context key. Nr r r r r r" O s r" c @ s e Zd ZdZdS )� CheckErrorz� Only one parsing class can raise this exception: Check. It can mean the condition lambda failed during a routine parsing building check. Nr r r r r r# T s r# c @ s e Zd ZdZdS )� ExplicitErrorz� Only one parsing class can raise this exception: Error. It can mean the parsing class was merely parsed or built with. Nr r r r r r$ Y s r$ c @ s e Zd ZdZdS )�NamedTupleErrorzu Only one parsing class can raise this exception: NamedTuple. It can mean the subcon is not of a valid type. Nr r r r r r% ^ s r% c @ s e Zd ZdZdS )�TimestampErrorzw Only one parsing class can raise this exception: Timestamp. It can mean the subcon unit or epoch are invalid. Nr r r r r r& c s r& c @ s e Zd ZdZdS )� UnionErrorz� Only one parsing class can raise this exception: Union. It can mean none of given subcons was properly selected, or trying to build without providing a proper value. Nr r r r r r' h s r' c @ s e Zd ZdZdS )� SelectErrorz� Only one parsing class can raise this exception: Select. It can mean neither subcon succeded when parsing or building. Nr r r r r r( m s r( c @ s e Zd ZdZdS )� SwitchErrorr Nr r r r r r) r s r) c @ s e Zd ZdZdS )�StopFieldErrorz� Only one parsing class can raise this exception: StopIf. It can mean the given condition was met during parsing or building. Nr r r r r r* w s r* c @ s e Zd ZdZdS )� PaddingErroraU Multiple parsing classes can raise this exception: PaddedString Padding Padded Aligned FixedSized NullTerminated NullStripped. It can mean multiple issues: the encoded string or bytes takes more bytes than padding allows, length parameter was invalid, pattern terminator or pad is not a proper bytes value, modulus was less than 2. Nr r r r r r+ | s r+ c @ s e Zd ZdZdS )�TerminatedErrorz� Only one parsing class can raise this exception: Terminated. It can mean EOF was not found as expected during parsing. Nr r r r r r, � s r, c @ s e Zd ZdZdS )� RawCopyErrorz� Only one parsing class can raise this exception: RawCopy. It can mean it cannot build as both data and value keys are missing from build dict object. Nr r r r r r- � s r- c @ s e Zd ZdZdS )� RotationErrorz� Only one parsing class can raise this exception: ProcessRotateLeft. It can mean the specified group is less than 1, data is not of valid length. Nr r r r r r. � s r. c @ s e Zd ZdZdS )� ChecksumErrorz{ Only one parsing class can raise this exception: Checksum. It can mean expected and actual checksum do not match. Nr r r r r r/ � s r/ c @ s e Zd ZdZdS )� CancelParsingz� This exception can only be raise explicitly by the user, and it causes the parsing class to stop what it is doing (interrupts parsing or building). Nr r r r r r0 � s r0 c @ s e Zd ZdZdS )� CipherErrorz� Two parsing classes can raise this exception: EncryptedSym EncryptedSymAead. It can mean none or invalid cipher object was provided. Nr r r r r r1 � s r1 c C s | � }|S �Nr )�arg�xr r r � singleton� s r5 c C st |dk rt d| |d��z| �|�}W n$ tyJ t d|f |d��Y n0 t|�|krpt d|t|�f |d��|S )Nr �%length must be non-negative, found %s�r z(stream.read() failed, requested %s bytesz=stream read less than specified amount, expected %d, found %d)r �read� Exception�len)�stream�lengthr �datar r r � stream_read� s r> c C s. z | � � W S ty( td|d��Y n0 d S )Nz+stream.read() failed when reading until EOFr7 )r8 r9 r �r; r r r r �stream_read_entire� s r@ c C s� t |t�s td|f |d��|dk r4td| |d��t|�|krXtd|t|�f |d��z| �|�}W n$ ty� td|f |d��Y n0 ||kr�td||f |d��d S )Nz*given non-bytes value, perhaps unicode? %rr7 r r6 z3bytes object of wrong length, expected %d, found %dz stream.write() failed, given %rz;stream written less than specified, expected %d, written %d)� isinstance�bytestringtyper r r: �writer9 )r; r= r< r Zwrittenr r r � stream_write� s rD c C s: z| � ||�W S ty4 td||f |d��Y n0 d S )Nz*stream.seek() failed, offset %s, whence %sr7 )�seekr9 r )r; �offset�whencer r r r � stream_seek� s rH c C s. z | � � W S ty( td|d��Y n0 d S )Nzstream.tell() failedr7 )�tellr9 r r? r r r � stream_tell� s rJ c C sH z$| � � }| �dd�}| �|� |W S tyB tddd��Y n0 d S )Nr � z stream. seek() tell() failed�???r7 )rI rE r9 r )r; �fallback�endr r r � stream_size� s rO c C sH z$| � � }| �d�}| �|� | W S tyB tddd��Y n0 d S )N� z#stream. read() seek() tell() failedrL r7 )rI r8 rE r9 r )r; rM r= r r r � stream_iseof� s rQ c sf e Zd Zeeed�dd��Zeed�� fdd� Zed�� fdd � Z e j feeed �� fd d � Z � Z S ) �BytesIOWithOffsets)r< r c C s" t | |�}t| ||�}t|| |�S r2 )rJ r> rR )r; r< r rF �contentsr r r � from_reading� s z BytesIOWithOffsets.from_reading)rS rF c s t � �|� || _|| _d S r2 )r r � parent_stream�parent_stream_offset)r rS rU rF r r r r � s zBytesIOWithOffsets.__init__)�returnc s t � �� | j S r2 )r rI rV �r r r r rI � s zBytesIOWithOffsets.tell)rF rG rW c s4 |t jkrt� �||� nt� �|| j � | �� S r2 )�io�SEEK_SETr rE rV rI )r rF rG r r r rE � s zBytesIOWithOffsets.seek)r r r � staticmethod�int�strrT �bytesr rI rY rZ rE r r r r r rR � s rR c @ s, e Zd Zdd� Zdd� Zdd� Zdd� Zd S ) �CodeGenc C s. g | _ d| _i | _i | _i | _i | _i | _d S �Nr )�blocks�nextid� parsercache� buildercache�linkedinstances� linkedparsers�linkedbuildersrX r r r r s zCodeGen.__init__c C s | j d7 _ | j S �NrP �rb rX r r r � allocateId s zCodeGen.allocateIdc s` dd� |� � D �}|d }t|�t|�� � � d�� fdd�|D ��}|| jvr\| j�|� d S )Nc S s g | ]}|� � r|�qS r )�strip��.0�sr r r � <listcomp> � z"CodeGen.append.<locals>.<listcomp>r � c 3 s | ]}|� d � V qd S r2 r rl �Ztrimr r � <genexpr> rp z!CodeGen.append.<locals>.<genexpr>)� splitlinesr: �lstrip�joinra �append)r �block� firstliner rr r rw s zCodeGen.appendc C s d� | jdg �S )Nrq r )rv ra rX r r r �toString s zCodeGen.toStringN)r r r r rj rw rz r r r r r_ s r_ c @ s e Zd Zdd� Zdd� ZdS )�KsyGenc C s i | _ i | _i | _d| _d S r` )� instances�enums�typesrb rX r r r r s zKsyGen.__init__c C s | j d7 _ | j S rh ri rX r r r rj & s zKsyGen.allocateIdN)r r r r rj r r r r r{ s r{ c C s dd� | � � D �S )Nc S s$ i | ] \}}|� d d��d�|�qS )�_�-)�replace�rstrip�rm �k�vr r r � <dictcomp>, rp z!hyphenatedict.<locals>.<dictcomp>)�items)�dr r r � hyphenatedict+ s r� c C s dd� | D �S )Nc S s g | ] }t |��qS r )r� )rm r� r r r ro 0 rp z!hyphenatelist.<locals>.<listcomp>r )�lr r r � hyphenatelist/ s r� c C s t | t�rt| j�S | S r2 )rA �Renamed� extractfield�subcon)�scr r r r� 3 s r� c C s t | �r| |�S | S r2 )�callable)�param�contextr r r �evaluate9 s r� c @ sH e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dd� Z dd� Z dd� Z dd� Zdd� Zdd� Zd d � Zd d � Zd d!� Zd"d#� ZdPd%d&�Zd'd(� Zd)d*� Zd+d,� Zd-d.� Zd/d0� ZdQd1d2�ZdRd4d5�Z dSd8d9�Z dTd:d;�Z dUd<d=�Z d>d?� Z d@dA� Z!dBdC� Z"dDdE� Z#e#Z$dFdG� Z%dHdI� Z&dJdK� Z'dLdM� Z(dNdO� Z)d$S )V� Constructa� 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. There are also other abstract classes sitting on top of this one. The external user API: * `parse` * `parse_stream` * `parse_file` * `build` * `build_stream` * `build_file` * `sizeof` * `compile` * `benchmark` Subclass authors should not override the external methods. Instead, another API is available: * `_parse` * `_build` * `_sizeof` * `_actualsize` * `_emitparse` * `_emitbuild` * `_emitseq` * `_emitprimitivetype` * `_emitfulltype` * `__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 be a string, or None by default. A single underscore "_" is a reserved name, used as up-level in nested containers. 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 often inherited from inner subconstructs but that depends on each class. c C s d | _ d| _d| _d | _d S )Nr F)�name�docs� flagbuildnone�parsedrX r r r r e s zConstruct.__init__c C s8 d| j j| jrd| j nd| jr$dnd| jr0dndf S )Nz <%s%s%s%s>� r � +nonbuild� +docs)r r r� r� r� rX r r r �__repr__k s zConstruct.__repr__c C sp i }t | d�r|�| j� g }| j}|d urJt |d�rB|�|j� |j}q$|D ] }t | |�rNt| |�||< qN|S )N�__dict__� __slots__)�hasattr�updater� r �extendr� �__base__�getattr)r �attrs�slots�cr� r r r � __getstate__n s zConstruct.__getstate__c C s" |� � D ]\}}t| ||� qd S r2 )r� �setattr)r r� r� �valuer r r � __setstate__} s zConstruct.__setstate__c C s t �| j�}|�| �� � |S r2 )�object�__new__r r� r� )r Zself2r r r �__copy__� s zConstruct.__copy__c K s | j t�|�fi |��S )a� Parse an in-memory buffer (often bytes object). Strings, buffers, memoryviews, and other complete buffers can be parsed with this method. Whenever data cannot be read, ConstructError or its derivative is raised. This method is NOT ALLOWED to raise any other exceptions although (1) user-defined lambdas can raise arbitrary exceptions which are propagated (2) external libraries like numpy can raise arbitrary exceptions which are propagated (3) some list and dict lookups can raise IndexError and KeyError which are propagated. Context entries are passed only as keyword parameters \*\*contextkw. :param \*\*contextkw: context entries, usually empty :returns: some value, usually based on bytes read from the stream but sometimes it is computed from nothing or from the context dictionary, sometimes its non-deterministic :raises ConstructError: raised for any reason )� parse_streamrY �BytesIO)r r= � contextkwr r r �parse� s zConstruct.parsec K sN t f i |��}d|_d|_d|_||_z| �||d�W S tyH Y n0 dS )z� Parse a stream. Files, pipes, sockets, and other streaming sources of data are handled by this method. See parse(). TFz (parsing)N)� Container�_parsing� _building�_sizing�_params� _parsereportr0 )r r; r� r� r r r r� � s zConstruct.parse_streamc K s@ t |d��"}| j|fi |��W d � S 1 s20 Y dS )z: Parse a closed binary file. See parse(). �rbN)�openr� )r �filenamer� �fr r r � parse_file� s zConstruct.parse_filec C s( | � |||�}| jd ur$| �||� |S r2 )�_parser� �r r; r� r �objr r r r� � s zConstruct._parsereportc C s t �dS ��Override in your subclass.N��NotImplementedError�r r; r� r r r r r� � s zConstruct._parsec K s$ t �� }| j||fi |�� |�� S )a� Build an object in memory (a bytes object). Whenever data cannot be written, ConstructError or its derivative is raised. This method is NOT ALLOWED to raise any other exceptions although (1) user-defined lambdas can raise arbitrary exceptions which are propagated (2) external libraries like numpy can raise arbitrary exceptions which are propagated (3) some list and dict lookups can raise IndexError and KeyError which are propagated. Context entries are passed only as keyword parameters \*\*contextkw. :param \*\*contextkw: context entries, usually empty :returns: bytes :raises ConstructError: raised for any reason )rY r� � build_stream�getvalue)r r� r� r; r r r �build� s zConstruct.buildc K s: t f i |��}d|_d|_d|_||_| �|||d� dS )zF Build an object directly into a stream. See build(). FTz (building)N)r� r� r� r� r� �_build)r r� r; r� r� r r r r� � s zConstruct.build_streamc K sB t |d��$}| j||fi |�� W d � n1 s40 Y dS )zI Build an object into a closed binary file. See build(). zw+bN)r� r� )r r� r� r� r� r r r � build_file� s zConstruct.build_filec C s t �dS r� r� �r r� r; r� r r r r r� � s zConstruct._buildc K s2 t f i |��}d|_d|_d|_||_| �|d�S )aP Calculate the size of this object, optionally using a context. Some constructs have fixed size (like FormatField), some have variable-size and can determine their size given a context entry (like Bytes(this.otherfield1)), and some cannot determine their size (like VarInt). Whenever size cannot be determined, SizeofError is raised. This method is NOT ALLOWED to raise any other exception, even if eg. context dictionary is missing a key, or subcon propagates ConstructError-derivative exception. Context entries are passed only as keyword parameters \*\*contextkw. :param \*\*contextkw: context entries, usually empty :returns: integer if computable, SizeofError otherwise :raises SizeofError: size could not be determined in actual context, or is impossible to be determined FTz(sizeof))r� r� r� r� r� �_sizeof)r r� r� r r r �sizeof� s zConstruct.sizeofc C s t |d��dS )r� r7 N�r �r r� r r r r r� � s zConstruct._sizeofc C s | � ||�S r2 �r� r� r r r � _actualsize� s zConstruct._actualsizeNc C s� t � }|�d� |�d| �|�� d| �|�� d�� |�� }|rtt|d��}|�|� W d � n1 sj0 Y tt� |� � �� � �� � }t j�|d�}t j�|�}t|dd�}t||j� |j|_|j|_|j|_|j} || _|| _|| _| | _ | S ) a� Transforms a construct into another construct that does same thing (has same parsing and building semantics) but is much faster when parsing. Already compiled instances just compile into itself. Optionally, partial source code can be saved to a text file. This is meant only to inspect the generated code, not to import it from external scripts. :returns: Compiled instance a� # generated by Construct, this source is for inspection only! do not import! from construct import * from construct.lib import * from io import BytesIO import struct import collections import itertools def restream(data, func): return func(BytesIO(data)) def reuse(obj, func): return func(obj) linkedinstances = {} linkedparsers = {} linkedbuilders = {} len_ = len sum_ = sum min_ = min max_ = max abs_ = abs z< def parseall(io, this): return zA def buildall(obj, io, this): return z= compiled = Compiled(parseall, buildall) �wtNr �exec) r_ rw � _compileparse� _compilebuildrz r� rC �hexlify�hashlib�sha1�encode�digest�decode� importlib� machinery� ModuleSpec�util�module_from_spec�compiler� r� re rf rg �compiled�source�module� modulename� defersubcon) r r� �coder� r� r� Z module_specr� r� r� r r r r� � s2 �� ( zConstruct.compilec C sh t | �|jv rdS |�dt | �� d| � d�� t| �}||jt | �< |j|jt | �< |j|jt | �< dS )�Used internally.Nz # linkedinstances[z] is z )�idre rw r� r� rf r� rg )r r� �fieldr r r �_compileinstance> s �� zConstruct._compileinstancec C sn z<t | �|jv r |jt | � W S | �|�}||jt | �< |W S tyh | �|� dt | �� d� Y S 0 dS )r� zlinkedparsers[z](io, this, '(???)')N)r� rc � _emitparser� r� �r r� Zemittedr r r r� J s zConstruct._compileparsec C sn z<t | �|jv r |jt | � W S | �|�}||jt | �< |W S tyh | �|� dt | �� d� Y S 0 dS )r� zlinkedbuilders[z](obj, io, this, '(???)')N)r� rd � _emitbuildr� r� r� r r r r� V s zConstruct._compilebuildc C s t �dS r� r� �r r� r r r r� b s zConstruct._emitparsec C s t �dS r� r� r� r r r r� f s zConstruct._emitbuildc s� ddl m } �����|��fdd�dd�}td| �}|dkrZ|��fdd�|d�| }d �|�}���� |��fd d�dd�}td| �}|dkr�|��fd d�|d�| }d �|�}��� � � ��� |� �fd d�dd�}td| �}|dk�r|� �fd d�|d�| }d �|�}� ��� |� �fdd�dd�}td| �}|dk�rn|� �fdd�|d�| }d �|�}g d�} d�| ��||||�} |�r�t|d��} | �| � W d � n1 �s�0 Y | S )a1 Measures performance of your construct (its parsing and building runtime), both for the original instance and the compiled instance. Uses timeit module, over at min 1 loop, and at max over 100 millisecond time. Optionally, results are saved to a text file for later inspection. Otherwise you can print the resulting string to terminal. :param sampledata: bytes, a valid blob parsable by this construct :param filename: optional, string, results are saved to that file :returns: string containing measurements r )�timeitc s �� � �S r2 �r� r �� sampledatar r r �<lambda>x rp z%Construct.benchmark.<locals>.<lambda>rP )�numberg�������?c s �� � �S r2 r� r r� r r r� { rp z{:.10f} sec/callc s �� � �S r2 �r� r �� sampleobjr r r r� rp c s �� � �S r2 r� r r� r r r� � rp c s � � ��S r2 r� r �r� r� r r r� � rp c s � � ��S r2 r� r r� r r r� � rp c s � � ��S r2 r� r �r� r� r r r� � rp c s � � ��S r2 r� r r� r r r� � rp )z Compiled instance performance:zparsing: {}zparsing compiled: {}zbuilding: {}zbuilding compiled: {}r rq r� N) r� r� r\ r r� r� rv r� rC ) r r� r� r� Z parsetime�runs� buildtimeZ parsetime2Z buildtime2�lines�resultsr� r )r� r� r� r r � benchmarkj s@ *zConstruct.benchmark�unnamed_schemac C s� ddl m} |� }d|_t�� }t� }tt|d�| �|�|j|j |j d�}|� ||� |� � }|r�t |d��} | �|� W d � n1 s�0 Y |S )Nr )�YAMLF�r� )�meta�seqr| r} r~ r� )Z ruamel.yamlr Zdefault_flow_stylerY �StringIOr{ �dict� _compileseqr| r} r~ �dumpr� r� rC ) r Z schemanamer� r �yaml�output�gen�mainr� r� r r r � export_ksy� s $ (zConstruct.export_ksyFr c C s\ |dkrt d��zt| �||��W S tyV tf ddi| �|||d ���g Y S 0 d S )N� �'construct does not implement KSY exportr� r4 rP )r r� �_emitseqr� r �_compilefulltype�r �ksy�bitwise� recursionr r r r � s zConstruct._compileseqc C sd |dkrt d��z| �||�W S ty^ d|�� }t| �|||d �d�|j|< | Y S 0 d S )Nr r ztype_%srP )r )r �_emitprimitivetyper� rj r r r~ )r r r r r� r r r �_compileprimitivetype� s z Construct._compileprimitivetypec C sR |dkrt d��zt| �||��W S tyL t| �|||d �d� Y S 0 d S )Nr r rP )�type)r r� � _emitfulltyper� r r r r r r r � s zConstruct._compilefulltypec C s t �dS r� r� �r r r r r r r � s zConstruct._emitseqc C s t �dS r� r� r r r r r � s z Construct._emitprimitivetypec C s t �dS r� r� r r r r r � s zConstruct._emitfulltypec C s t | |d�S )zc Used for renaming subcons, usually part of a Struct, like Struct("index" / Byte). )�newname)r� �r r� r r r � __rtruediv__� s zConstruct.__rtruediv__c C s6 t |t�rt| |d�S t|�r*t| |d�S td��dS �zz Used for adding docstrings and parsed hooks to subcons, like "field" / Byte * "docstring" * processfunc. )�newdocs)� newparsedz1operator * can only be used with string or lambdaN�rA � stringtypesr� r� r �r �otherr r r �__mul__� s zConstruct.__mul__c C s6 t |t�rt| |d�S t|�r*t| |d�S td��dS r r r" r r r �__rmul__� s zConstruct.__rmul__c C s8 t | t�r| jn| g}t |t�r&|jn|g}t|| � S )zM Used for making Struct like ("index"/Byte + "prefix"/Byte). )rA �Struct�subcons�r r# �lhs�rhsr r r �__add__� s zConstruct.__add__c C s8 t | t�r| jn| g}t |t�r&|jn|g}t|| � S )zA Used for making Sequences like (Byte >> Short). )rA �Sequencer' r( r r r � __rshift__� s zConstruct.__rshift__c C s: t |t�rtd��t |t�s$t|�r.t|| �S td��dS )zK Used for making Arrays like Byte[5] and Byte[this.count]. zNsubcon[N] syntax can only be used for Arrays, use GreedyRange(subcon) instead?z2subcon[N] syntax expects integer or context lambdaN)rA �slicer r\ r� �Array)r �countr r r � __getitem__ s zConstruct.__getitem__)N)N)r� N)Fr )Fr )Fr )*r r r r r r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r r r r r r r r Z__rdiv__r$ r% r+ r- r1 r r r r r� @ sN $ @ : r� c s@ e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Z� Z S ) � Subconstructz� Abstract subconstruct (wraps an inner construct, inheriting its name and flags). Parsing and building is by default deferred to subcon, same as sizeof. :param subcon: Construct instance c s. t |t�std��t� �� || _|j| _d S )Nz"subcon should be a Construct field)rA r� � TypeErrorr r r� r� �r r� r r r r s zSubconstruct.__init__c C s@ d| j j| jrd| j nd| jr$dnd| jr0dndt| j�f S )Nz <%s%s%s%s %s>r� r r� r� )r r r� r� r� �reprr� rX r r r r� s zSubconstruct.__repr__c C s | j �|||�S r2 )r� r� r� r r r r� s zSubconstruct._parsec C s | j �||||�S r2 �r� r� r� r r r r� # s zSubconstruct._buildc C s | j �||�S r2 �r� r� r� r r r r� & s zSubconstruct._sizeof) r r r r r r� r� r� r� r r r r r r2 s r2 c @ s0 e Zd ZdZdd� Zdd� Zdd� Zdd � Zd S ) �Adapterz� Abstract adapter class. Needs to implement `_decode()` for parsing and `_encode()` for building. :param subcon: Construct instance c C s | j �|||�}| �|||�S r2 )r� r� �_decoder� r r r r� 2 s zAdapter._parsec C s$ | � |||�}| j�||||�}|S r2 )�_encoder� r� )r r� r; r� r �obj2�buildretr r r r� 6 s zAdapter._buildc C s t �d S r2 r� �r r� r� r r r r r9 ; s zAdapter._decodec C s t �d S r2 r� r= r r r r: > s zAdapter._encodeN)r r r r r� r� r9 r: r r r r r8 * s r8 c @ s e Zd ZdZdd� ZdS )�SymmetricAdapterz� Abstract adapter class. Needs to implement `_decode()` only, for both parsing and building. :param subcon: Construct instance c C s | � |||�S r2 )r9 r= r r r r: J s zSymmetricAdapter._encodeN)r r r r r: r r r r r> B s r> c @ s e Zd ZdZdd� Zdd� ZdS )� Validatorz� Abstract class that validates a condition on the encoded/decoded object. Needs to implement `_validate()` that returns a bool (or a truthy value) :param subcon: Construct instance c C s$ | � |||�s td|f |d��|S )Nz object failed validation: %sr7 )� _validater r= r r r r9 V s zValidator._decodec C s t �d S r2 r� r= r r r r@ [ s zValidator._validateN)r r r r r9 r@ r r r r r? N s r? c @ s8 e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd S ) �Tunnelz� Abstract class that allows other constructs to read part of the stream as if they were reading the entire stream. See Prefixed for example. Needs to implement `_decode()` for parsing and `_encode()` for building. c C s, t ||�}| �|||�}| jj|fi |��S r2 )r@ r9 r� r� �r r; r� r r= r r r r� e s z Tunnel._parsec C sF t �� }| j�||||�}|�� }| �|||�}t||t|�|� |S r2 )rY r� r� r� r� r: rD r: �r r� r; r� r �stream2r< r= r r r r� j s z Tunnel._buildc C s t |d��d S �Nr7 r� r� r r r r� r s zTunnel._sizeofc C s t �d S r2 r� �r r= r� r r r r r9 u s zTunnel._decodec C s t �d S r2 r� rF r r r r: x s zTunnel._encodeN) r r r r r� r� r� r9 r: r r r r rA _ s rA c sL e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zdd d �Zdd d�Z � Z S )�Compiledr� c s& t � �� d | _d | _|| _|| _d S r2 )r r r� r� � parsefunc� buildfunc)r rH rI r r r r s zCompiled.__init__c C s | � ||�S r2 )rH r� r r r r� � s zCompiled._parsec C s | � |||�S r2 )rI r� r r r r� � s zCompiled._buildc C s | j �||�S r2 )r� r� r� r r r r� � s zCompiled._sizeofNc C s | S r2 r )r r� r r r r� � s zCompiled.compilec C s | j �||�S r2 )r� r� )r r� r� r r r r� � s zCompiled.benchmark)N)N) r r r r r r� r� r� r� r� r r r r r rG | s rG c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )�Bytesa� Field consisting of a specified number of bytes. Parses into a bytes (of given length). Builds into the stream directly (but checks that given object matches specified length). Can also build from an integer for convenience (although BytesInteger should be used instead). Size is the specified length. Can also build from a bytearray. :param length: integer or context lambda :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StringError: building from non-bytes value, perhaps unicode Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Bytes(4) >>> d.parse(b'beef') b'beef' >>> d.build(b'beef') b'beef' >>> d.build(0) b'\x00\x00\x00\x00' >>> d.sizeof() 4 >>> d = Struct( ... "length" / Int8ub, ... "data" / Bytes(this.length), ... ) >>> d.parse(b"\x04beef") Container(length=4, data=b'beef') >>> d.sizeof() construct.core.SizeofError: cannot calculate size, key not found in context c s t � �� || _d S r2 �r r r< )r r< r r r r � s zBytes.__init__c C s& t | j�r| �|�n| j}t|||�S r2 )r� r< r> )r r; r� r r< r r r r� � s z Bytes._parsec C s\ t | j�r| �|�n| j}t|t�r.t||�n|}t|�tu rFt|�n|}t||||� |S r2 ) r� r< rA r\ � integer2bytesr � bytearrayr^ rD )r r� r; r� r r< r= r r r r� � s z Bytes._buildc C sD z t | j�r| �|�n| jW S ttfy> td|d��Y n0 d S �N�/cannot calculate size, key not found in contextr7 )r� r< �KeyError�AttributeErrorr r� r r r r� � s z Bytes._sizeofc C s d| j � d�S )N�io.read(�)�r< r� r r r r� � s zBytes._emitparsec C s dS �Nz(io.write(obj), obj)[1]r r� r r r r� � s zBytes._emitbuildc C s t | jd�S �N��size)r r< r r r r r � s zBytes._emitfulltype� r r r r r r� r� r� r� r� r r r r r r rJ � s $ rJ c @ s8 e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd S ) � GreedyBytesa� Field consisting of unknown number of bytes. Parses the stream to the end. Builds into the stream directly (without checks). Size is undefined. Can also build from a bytearray. :raises StreamError: stream failed when reading until EOF :raises StringError: building from non-bytes value, perhaps unicode Example:: >>> GreedyBytes.parse(b"asislight") b'asislight' >>> GreedyBytes.build(b"asislight") b'asislight' c C s t ||�S r2 )r@ r� r r r r� � s zGreedyBytes._parsec C s. t |�tu rt|�n|}t||t|�|� |S r2 )r rM r^ rD r: �r r� r; r� r r= r r r r� � s zGreedyBytes._buildc C s dS )Nz io.read()r r� r r r r� � s zGreedyBytes._emitparsec C s dS rU r r� r r r r� � s zGreedyBytes._emitbuildc C s t dd�S )NT)�size_eos�r r r r r r � s zGreedyBytes._emitfulltypeN) r r r r r� r� r� r� r r r r r rZ � s rZ c s� z$� � � }t� t|d t|d �}W n( tyL t� tdtddd� �}Y n0 � fdd�}� fdd�}� fd d �}||_||_||_|S ) a� Converts the stream from bytes to bits, and passes the bitstream to underlying subcon. Bitstream is a stream that contains 8 times as many bytes, and each byte is either \\x00 or \\x01 (in documentation those bytes are called bits). Parsing building and size are deferred to subcon, although size gets divided by 8 (therefore the subcon's size must be a multiple of 8). Note that by default the bit ordering is from MSB to LSB for every byte (ie. bit-level big-endian). If you need it reversed, wrap this subcon with :class:`construct.core.BitsSwapped`. :param subcon: Construct instance, any field that works with bits (like BitsInteger) or is bit-byte agnostic (like Struct or Flag) See :class:`~construct.core.Transformed` and :class:`~construct.core.Restreamed` for raisable exceptions. Example:: >>> d = Bitwise(Struct( ... 'a' / Nibble, ... 'b' / Bytewise(Float32b), ... 'c' / Padding(4), ... )) >>> d.parse(bytes(5)) Container(a=0, b=0.0, c=None) >>> d.sizeof() 5 Obtaining other byte or bit orderings:: >>> d = Bitwise(Bytes(16)) >>> d.parse(b'\x01\x03') b'\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x01\x01' >>> d = BitsSwapped(Bitwise(Bytes(16))) >>> d.parse(b'\x01\x03') b'\x01\x00\x00\x00\x00\x00\x00\x00\x01\x01\x00\x00\x00\x00\x00\x00' � rP c S s | d S �Nr^ r ��nr r r r� ) rp zBitwise.<locals>.<lambda>c s � j | dd�S �NT�r �r �r r �r� r r r * s zBitwise.<locals>._emitseqc s � j | dd�S rb �r re rf r r r , s z#Bitwise.<locals>._emitprimitivetypec s � j | dd�S rb �r re rf r r r . s z Bitwise.<locals>._emitfulltype) r� � Transformed� bytes2bits� bits2bytesr � Restreamedr r r �r� rX �macror r r r rf r �Bitwise s " ro c s� z$� � � }t� t|d t|d �}W n( tyL t� tdtddd� �}Y n0 � fdd�}� fdd�}� fd d �}||_||_||_|S ) a� Converts the bitstream back to normal byte stream. Must be used within :class:`~construct.core.Bitwise`. Parsing building and size are deferred to subcon, although size gets multiplied by 8. :param subcon: Construct instance, any field that works with bytes or is bit-byte agnostic See :class:`~construct.core.Transformed` and :class:`~construct.core.Restreamed` for raisable exceptions. Example:: >>> d = Bitwise(Struct( ... 'a' / Nibble, ... 'b' / Bytewise(Float32b), ... 'c' / Padding(4), ... )) >>> d.parse(bytes(5)) Container(a=0, b=0.0, c=None) >>> d.sizeof() 5 r^ rP c S s | d S r_ r r` r r r r� Q rp zBytewise.<locals>.<lambda>c s � j | dd�S �NFrc rd re rf r r r R s zBytewise.<locals>._emitseqc s � j | dd�S rp rg re rf r r r T s z$Bytewise.<locals>._emitprimitivetypec s � j | dd�S rp rh re rf r r r V s z Bytewise.<locals>._emitfulltype) r� ri rk rj r rl r r r rm r rf r �Bytewise6 s rq c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )� FormatFielda� Field that uses `struct` module to pack and unpack CPU-sized integers and floats and booleans. This is used to implement most Int* Float* fields, but for example cannot pack 24-bit integers, which is left to :class:`~construct.core.BytesInteger` class. For booleans I also recommend using Flag class instead. See `struct module <https://docs.python.org/3/library/struct.html>`_ documentation for instructions on crafting format strings. Parses into an integer or float or boolean. Builds from an integer or float or boolean into specified byte count and endianness. Size is determined by `struct` module according to specified format string. :param endianity: string, character like: < > = :param format: string, character like: B H L Q b h l q e f d ? :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises FormatFieldError: wrong format string, or struct.(un)pack complained about the value Example:: >>> d = FormatField(">", "H") or Int16ub >>> d.parse(b"\x01\x00") 256 >>> d.build(256) b"\x01\x00" >>> d.sizeof() 2 c sT |t d�vrtd|��|t d�vr,td|��t� �� || | _t�|| �| _d S )Nz=<>z endianity must be like: = < >z fdBHLQbhlqe?z,format must be like: B H L Q b h l q e f d ?)�listr r r �fmtstr�struct�calcsizer< )r � endianityr r r r r z s zFormatField.__init__c C sL t || j|�}zt�| j|�d W S tyF td| j |d��Y n0 d S )Nr z struct %r error during parsingr7 )r> r< ru �unpackrt r9 r rB r r r r� � s zFormatField._parsec C sP zt �| j|�}W n( ty: td| j|f |d��Y n0 t||| j|� |S )Nz/struct %r error during building, given value %rr7 )ru �packrt r9 r rD r< r[ r r r r� � s zFormatField._buildc C s | j S r2 rT r� r r r r� � s zFormatField._sizeofc C s< d|� � � �}|�|� dt| j�� d�� |� d| j� d�S )N� formatfield_� = struct.Struct(rS z.unpack(io.read(z))[0])rj rw r5 rt r< �r r� �fnamer r r r� � s zFormatField._emitparsec C s6 d|� � � �}|�|� dt| j�� d�� d|� d�S )Nrz r{ rS � (io.write(z.pack(obj)), obj)[1])rj rw r5 rt r| r r r r� � s zFormatField._emitbuildc C s� | j \}}|�� }|dkp*|dko*tjdk}|dv rx|rX|r@J �|rHJ �dd| j f S d|rbdnd | j|rpd nd f S |d v r�|r�J �d | j|r�d nd f S d S )N�<�=�littleZbhlqBHLQ�b%sr^ �%s%s%srn �u�le�be�fdzf%s%s)rt �islower�sys� byteorderr< )r r r rw r �signed�swappedr r r r � s z FormatField._emitprimitivetype� r r r r r r� r� r� r� r� r r r r r r rr a s rr c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )� BytesIntegera� Field that packs integers of arbitrary size. Int24* fields use this class. Parses into an integer. Builds from an integer into specified byte count and endianness. Size is specified in ctor. Analog to :class:`~construct.core.BitsInteger` which operates on bits. In fact:: BytesInteger(n) <--> Bitwise(BitsInteger(8*n)) BitsInteger(8*n) <--> Bytewise(BytesInteger(n)) Byte ordering refers to bytes (chunks of 8 bits) so, for example:: BytesInteger(n, swapped=True) <--> Bitwise(BitsInteger(8*n, swapped=True)) :param length: integer or context lambda, number of bytes in the field :param signed: bool, whether the value is signed (two's complement), default is False (unsigned) :param swapped: bool or context lambda, whether to swap byte order (little endian), default is False (big endian) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises IntegerError: length is negative or zero :raises IntegerError: value is not an integer :raises IntegerError: number does not fit given width and signed parameters Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = BytesInteger(4) or Int32ub >>> d.parse(b"abcd") 1633837924 >>> d.build(1) b'\x00\x00\x00\x01' >>> d.sizeof() 4 Fc s t � �� || _|| _|| _d S r2 �r r r< r� r� �r r< r� r� r r r r � s zBytesInteger.__init__c C s� t | j|�}|dkr(td|� d�|d��t|||�}t | j|�rHt|�}zt|| j�W S ty� } z tt |�|d��W Y d }~n d }~0 0 d S �Nr �length � must be positiver7 ) r� r< r r> r� � swapbytesZ bytes2integerr� � ValueErrorr] �r r; r� r r< r= �er r r r� � s zBytesInteger._parsec C s� t |t�s td|� d�|d��t| j|�}|dkrFtd|� d�|d��zt||| j�}W n4 ty� } z tt|�|d��W Y d }~n d }~0 0 t| j |�r�t |�}t ||||� |S �N�value � is not an integerr7 r r� r� ) rA � integertypesr r� r< rL r� r� r] r� r� rD �r r� r; r� r r< r= r� r r r r� � s & zBytesInteger._buildc C s6 zt | j|�W S ttfy0 td|d��Y n0 d S rN �r� r< rP rQ r r� r r r r� � s zBytesInteger._sizeofc C s& d| j � d| j� d| j � d| j� d� S )Nz bytes2integer(swapbytes(io.read(�)) if � else io.read(�), rS �r< r� r� r� r r r r� � s zBytesInteger._emitparsec C s. d| j � d| j� d| j� d| j � d| j� d� S )Nz(((io.write(swapbytes(integer2bytes(obj, �, �)) if (z) else integer2bytes(obj, � ))), obj)[1]�r< r� r� r� r r r r� � s zBytesInteger._emitbuildc C s^ |r(| j rJ �| jrJ �dd| j f S t| j�r6J �d| j rBdnd| j| jrRdndf S d S )Nr� r^ r� rn r� r� r� )r� r� r< r� r r r r r s z BytesInteger._emitprimitivetype)FFr� r r r r r� � s $ r� c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )� BitsIntegera� Field that packs arbitrarily large (or small) integers. Some fields (Bit Nibble Octet) use this class. Must be enclosed in :class:`~construct.core.Bitwise` context. Parses into an integer. Builds from an integer into specified bit count and endianness. Size (in bits) is specified in ctor. Analog to :class:`~construct.core.BytesInteger` which operates on bytes. In fact:: BytesInteger(n) <--> Bitwise(BitsInteger(8*n)) BitsInteger(8*n) <--> Bytewise(BytesInteger(n)) Note that little-endianness is only defined for multiples of 8 bits. Byte ordering (i.e. `swapped` parameter) refers to bytes (chunks of 8 bits) so, for example:: BytesInteger(n, swapped=True) <--> Bitwise(BitsInteger(8*n, swapped=True)) Swapped argument was recently fixed. To obtain previous (faulty) behavior, you can use `ByteSwapped`, `BitsSwapped` and `Bitwise` in whatever particular order (see examples). :param length: integer or context lambda, number of bits in the field :param signed: bool, whether the value is signed (two's complement), default is False (unsigned) :param swapped: bool or context lambda, whether to swap byte order (little endian), default is False (big endian) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises IntegerError: length is negative or zero :raises IntegerError: value is not an integer :raises IntegerError: number does not fit given width and signed parameters :raises IntegerError: little-endianness selected but length is not multiple of 8 bits Can propagate any exception from the lambda, possibly non-ConstructError. Examples:: >>> d = Bitwise(BitsInteger(8)) or Bitwise(Octet) >>> d.parse(b"\x10") 16 >>> d.build(255) b'\xff' >>> d.sizeof() 1 Obtaining other byte or bit orderings:: >>> d = BitsInteger(2) >>> d.parse(b'\x01\x00') # Bit-Level Big-Endian 2 >>> d = ByteSwapped(BitsInteger(2)) >>> d.parse(b'\x01\x00') # Bit-Level Little-Endian 1 >>> d = BitsInteger(16) # Byte-Level Big-Endian, Bit-Level Big-Endian >>> d.build(5 + 19*256) b'\x00\x00\x00\x01\x00\x00\x01\x01\x00\x00\x00\x00\x00\x01\x00\x01' >>> d = BitsInteger(16, swapped=True) # Byte-Level Little-Endian, Bit-Level Big-Endian >>> d.build(5 + 19*256) b'\x00\x00\x00\x00\x00\x01\x00\x01\x00\x00\x00\x01\x00\x00\x01\x01' >>> d = ByteSwapped(BitsInteger(16)) # Byte-Level Little-Endian, Bit-Level Little-Endian >>> d.build(5 + 19*256) b'\x01\x00\x01\x00\x00\x00\x00\x00\x01\x01\x00\x00\x01\x00\x00\x00' >>> d = ByteSwapped(BitsInteger(16, swapped=True)) # Byte-Level Big-Endian, Bit-Level Little-Endian >>> d.build(5 + 19*256) b'\x01\x01\x00\x00\x01\x00\x00\x00\x01\x00\x01\x00\x00\x00\x00\x00' Fc s t � �� || _|| _|| _d S r2 r� r� r r r r K s zBitsInteger.__init__c C s� t | j|�}|dkr(td|� d�|d��t|||�}z"t | j|�rJt|�}t|| j�W S ty� } z tt |�|d��W Y d }~n d }~0 0 d S r� ) r� r< r r> r� �swapbytesinbitsZ bits2integerr� r� r] r� r r r r� Q s zBitsInteger._parsec C s� t |t�s td|� d�|d��t| j|�}|dkrFtd|� d�|d��z&t||| j�}t| j|�rjt|�}W n4 t y� } z tt |�|d��W Y d }~n d }~0 0 t ||||� |S r� ) rA r� r r� r< Z integer2bitsr� r� r� r� r] rD r� r r r r� ] s &zBitsInteger._buildc C s6 zt | j|�W S ttfy0 td|d��Y n0 d S rN r� r� r r r r� l s zBitsInteger._sizeofc C s& d| j � d| j� d| j � d| j� d� S )Nz%bits2integer(swapbytesinbits(io.read(r� r� r� rS r� r� r r r r� r s zBitsInteger._emitparsec C s. d| j � d| j� d| j� d| j � d| j� d� S )Nz-((io.write(swapbytesinbits(integer2bits(obj, r� r� z) else integer2bits(obj, r� r� r� r r r r� u s zBitsInteger._emitbuildc C s | j r J �| jrJ �d| jf S �Nr� )r� r� r< r r r r r x s z BitsInteger._emitprimitivetype)FFr� r r r r r� s > r� c C s t d�S )z>A 1-bit integer, must be enclosed in a Bitwise (eg. BitStruct)rP �r� r r r r �Bit~ s r� c C s t d�S )z>A 4-bit integer, must be enclosed in a Bitwise (eg. BitStruct)� r� r r r r �Nibble� s r� c C s t d�S )z>A 8-bit integer, must be enclosed in a Bitwise (eg. BitStruct)r^ r� r r r r �Octet� s r� c C s t dd�S )z"Unsigned, big endian 8-bit integer�>�B�rr r r r r �Int8ub� s r� c C s t dd�S )z#Unsigned, big endian 16-bit integerr� �Hr� r r r r �Int16ub� s r� c C s t dd�S )z#Unsigned, big endian 32-bit integerr� �Lr� r r r r �Int32ub� s r� c C s t dd�S )z#Unsigned, big endian 64-bit integerr� �Qr� r r r r �Int64ub� s r� c C s t dd�S )z Signed, big endian 8-bit integerr� �br� r r r r �Int8sb� s r� c C s t dd�S )z!Signed, big endian 16-bit integerr� �hr� r r r r �Int16sb� s r� c C s t dd�S )z!Signed, big endian 32-bit integerr� r� r� r r r r �Int32sb� s r� c C s t dd�S )z!Signed, big endian 64-bit integerr� �qr� r r r r �Int64sb� s r� c C s t dd�S )z%Unsigned, little endian 8-bit integerr r� r� r r r r �Int8ul� s r� c C s t dd�S )z&Unsigned, little endian 16-bit integerr r� r� r r r r �Int16ul� s r� c C s t dd�S )z&Unsigned, little endian 32-bit integerr r� r� r r r r �Int32ul� s r� c C s t dd�S )z&Unsigned, little endian 64-bit integerr r� r� r r r r �Int64ul� s r� c C s t dd�S )z#Signed, little endian 8-bit integerr r� r� r r r r �Int8sl� s r� c C s t dd�S )z$Signed, little endian 16-bit integerr r� r� r r r r �Int16sl� s r� c C s t dd�S )z$Signed, little endian 32-bit integerr r� r� r r r r �Int32sl� s r� c C s t dd�S )z$Signed, little endian 64-bit integerr r� r� r r r r �Int64sl� s r� c C s t dd�S )z(Unsigned, native endianity 8-bit integerr� r� r� r r r r �Int8un� s r� c C s t dd�S )z)Unsigned, native endianity 16-bit integerr� r� r� r r r r �Int16un� s r� c C s t dd�S )z)Unsigned, native endianity 32-bit integerr� r� r� r r r r �Int32un� s r� c C s t dd�S )z)Unsigned, native endianity 64-bit integerr� r� r� r r r r �Int64un� s r� c C s t dd�S )z&Signed, native endianity 8-bit integerr� r� r� r r r r �Int8sn� s r� c C s t dd�S )z'Signed, native endianity 16-bit integerr� r� r� r r r r �Int16sn� s r� c C s t dd�S )z'Signed, native endianity 32-bit integerr� r� r� r r r r �Int32sn� s r� c C s t dd�S )z'Signed, native endianity 64-bit integerr� r� r� r r r r �Int64sn� s r� c C s t dd�S )z1Big endian, 16-bit IEEE 754 floating point numberr� r� r� r r r r �Float16b� s r� c C s t dd�S )z4Little endian, 16-bit IEEE 754 floating point numberr r� r� r r r r �Float16l� s r� c C s t dd�S )z7Native endianity, 16-bit IEEE 754 floating point numberr� r� r� r r r r �Float16n� s r� c C s t dd�S )z-Big endian, 32-bit IEEE floating point numberr� r� r� r r r r �Float32b s r� c C s t dd�S )z0Little endian, 32-bit IEEE floating point numberr r� r� r r r r �Float32l s r� c C s t dd�S )z3Native endianity, 32-bit IEEE floating point numberr� r� r� r r r r �Float32n s r� c C s t dd�S )z-Big endian, 64-bit IEEE floating point numberr� r� r� r r r r �Float64b s r� c C s t dd�S )z0Little endian, 64-bit IEEE floating point numberr r� r� r r r r �Float64l s r� c C s t dd�S )z3Native endianity, 64-bit IEEE floating point numberr� r� r� r r r r �Float64n s r� r� c C s t dddd�S )zFA 3-byte big-endian unsigned integer, as used in ancient file formats.r F�r� r� �r� r r r r �Int24ub# s r� c C s t dddd�S )zIA 3-byte little-endian unsigned integer, as used in ancient file formats.r FTr� r� r r r r �Int24ul' s r� c C s t ddtd�S )zIA 3-byte native-endian unsigned integer, as used in ancient file formats.r Fr� �r� �nativer r r r �Int24un+ s r� c C s t dddd�S )zDA 3-byte big-endian signed integer, as used in ancient file formats.r TFr� r� r r r r �Int24sb/ s r� c C s t dddd�S )zGA 3-byte little-endian signed integer, as used in ancient file formats.r Tr� r� r r r r �Int24sl3 s r� c C s t ddtd�S )zGA 3-byte native-endian signed integer, as used in ancient file formats.r Tr� r� r r r r �Int24sn7 s r� c @ s( e Zd ZdZdd� Zdd� Zdd� ZdS ) �VarInta, VarInt encoded unsigned integer. Each 7 bits of the number are encoded in one byte of the stream, where leftmost bit (MSB) is unset when byte is terminal. Scheme is defined at Google site related to `Protocol Buffers <https://developers.google.com/protocol-buffers/docs/encoding>`_. Can only encode non-negative numbers. Parses into an integer. Builds from an integer. Size is undefined. :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises IntegerError: given a negative value, or not an integer Example:: >>> VarInt.build(1) b'\x01' >>> VarInt.build(2**100) b'\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x80\x04' c C sT g }t t|d|��}|�|d@ � |d@ dkrq2qd}t|�D ]}|d> |B }q>|S )NrP � � r � )�byte2intr> rw �reversed)r r; r� r �accr� �numr r r r� Q s z VarInt._parsec C s� t |t�s td|� d�|d��|dk r8td|� �|d��|}t� }|dkrf|�d|d@ B � |dL }qB|�|� t|t|�t|�|� |S ) Nr� r� r7 r z)VarInt cannot build from negative number r� r� r� )rA r� r rM rw rD r^ r: )r r� r; r� r r4 r� r r r r� ] s z VarInt._buildc C s dS )NZvlq_base128_ler r r r r r k s zVarInt._emitprimitivetypeN)r r r r r� r� r r r r r r� = s r� c @ s e Zd ZdZdd� Zdd� ZdS )�ZigZaga� ZigZag encoded signed integer. This is a variant of VarInt encoding that also can encode negative numbers. Scheme is defined at Google site related to `Protocol Buffers <https://developers.google.com/protocol-buffers/docs/encoding>`_. Can also encode negative numbers. Parses into an integer. Builds from an integer. Size is undefined. :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises IntegerError: given not an integer Example:: >>> ZigZag.build(-3) b'\x05' >>> ZigZag.build(3) b'\x06' c C s6 t �|||�}|d@ dkr$|d }n|d d }|S )NrP r rK )r� r� )r r; r� r r4 r r r r� � s z ZigZag._parsec C sT t |t�s td|� d�|d��|dkr0d| }ndt|� d }t�||||� |S )Nr� r� r7 r rK rP )rA r� r �absr� r� )r r� r; r� r r4 r r r r� � s z ZigZag._buildN�r r r r r� r� r r r r r� o s r� rP rK r� )�ascii�utf8�utf_8�u8�utf16�utf_16�u16� utf_16_be� utf_16_le�utf32�utf_32�u32� utf_32_be� utf_32_lec C s4 | � dd��� } | tvr(td| tf ��tt| �S )r� r� r z encoding %r not found among %r)r� �lower�possiblestringencodingsr r^ ��encodingr r r � encodingunit� s r� c s@ e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Z� Z S ) � StringEncodedr� c s" t � �|� |std��|| _d S )Nz)String* classes require explicit encoding)r r r r� )r r� r� r r r r � s zStringEncoded.__init__c C s6 z|� | j�W S td| j�d|����Y n0 d S )N�cannot use encoding z to decode )r� r� r r= r r r r9 � s zStringEncoded._decodec C sX t |t�std|d��|dkr"dS z|�| j�W S td| j�d|����Y n0 d S )Nz/string encoding failed, expected unicode stringr7 r rp r z to encode )rA Zunicodestringtyper r� r� r= r r r r: � s zStringEncoded._encodec C s t �d S r2 r� r� r r r r� � s zStringEncoded._emitparsec C s t �d S r2 r� r� r r r r� � s zStringEncoded._emitbuild� r r r r r r9 r: r� r� r r r r r r � s r c s4 t t�ttt� �d��� �}� �fdd�}||_|S )u+ Configurable, fixed-length or variable-length string field. When parsing, the byte string is stripped of null bytes (per encoding unit), then decoded. Length is an integer or context lambda. When building, the string is encoded and then padded to specified length. If encoded string is larger than the specified length, it fails with PaddingError. Size is same as length parameter. .. warning:: PaddedString and CString only support encodings explicitly listed in :class:`~construct.core.possiblestringencodings` . :param length: integer or context lambda, length in bytes (not unicode characters) :param encoding: string like: utf8 utf16 utf32 ascii :raises StringError: building a non-unicode string :raises StringError: selected encoding is not on supported list Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = PaddedString(10, "utf8") >>> d.build(u"Афон") b'\xd0\x90\xd1\x84\xd0\xbe\xd0\xbd\x00\x00' >>> d.parse(_) u'Афон' ��padc s t �d� d�S )N�strz)rX r r� r] re �r� r< r r r � s z#PaddedString.<locals>._emitfulltype)r � FixedSized� NullStrippedrZ r� r )r< r� rn r r r r � PaddedString� s r c s< t t�t�� �}� �fdd�}||_� �fdd�}||_|S )u� Length-prefixed string. The length field can be variable length (such as VarInt) or fixed length (such as Int64ub). :class:`~construct.core.VarInt` is recommended when designing new protocols. Stored length is in bytes, not characters. Size is not defined. :param lengthfield: Construct instance, field used to parse and build the length (like VarInt Int64ub) :param encoding: string like: utf8 utf16 utf32 ascii :raises StringError: building a non-unicode string Example:: >>> d = PascalString(VarInt, "utf8") >>> d.build(u"Афон") b'\x08\xd0\x90\xd1\x84\xd0\xbe\xd0\xbd' >>> d.parse(_) u'Афон' c s d�� | �� dt� �� d�S )NrR z ).decode(rS )r� r5 �r� �r� � lengthfieldr r r� s z PascalString.<locals>._emitparsec s$ t d��| |�d�t ddd� d�gS )Nr �r� r r= r] )r� rX r r� �r r re r r r r s �z PascalString.<locals>._emitseq)r �PrefixedrZ r� r )r r� rn r� r r r r � PascalString� s r c s, t ttt� �d�� �}� fdd�}||_|S )u@ String ending in a terminating null byte (or null bytes in case of UTF16 UTF32). .. warning:: String and CString only support encodings explicitly listed in :class:`~construct.core.possiblestringencodings` . :param encoding: string like: utf8 utf16 utf32 ascii :raises StringError: building a non-unicode string :raises StringError: selected encoding is not on supported list Example:: >>> d = CString("utf8") >>> d.build(u"Афон") b'\xd0\x90\xd1\x84\xd0\xbe\xd0\xbd\x00' >>> d.parse(_) u'Афон' )�termc s t d� d�S )Nr )r r� r] re r� r r r $ s z CString.<locals>._emitfulltype)r �NullTerminatedrZ r� r �r� rn r r r� r �CString s r c s t t� �}� fdd�}||_|S )u String that reads entire stream until EOF, and writes a given string as-is. Analog to :class:`~construct.core.GreedyBytes` but also applies unicode-to-bytes encoding. :param encoding: string like: utf8 utf16 utf32 ascii :raises StringError: building a non-unicode string :raises StreamError: stream failed when reading until EOF Example:: >>> d = GreedyString("utf8") >>> d.build(u"Афон") b'\xd0\x90\xd1\x84\xd0\xbe\xd0\xbd' >>> d.parse(_) u'Афон' c s t dd� d�S )NTr] )r\ r r� r] re r� r r r < s z#GreedyString.<locals>._emitfulltype)r rZ r r r r� r � GreedyString* s r c @ s@ e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dS )�Flaga� One byte (or one bit) field that maps to True or False. Other non-zero bytes are also considered True. Size is defined as 1. :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Example:: >>> Flag.parse(b"\x01") True >>> Flag.build(True) b'\x01' c C s t |d|�dkS )NrP � )r> r� r r r r� T s z Flag._parsec C s t ||r dndd|� |S )N� r rP )rD r� r r r r� W s z Flag._buildc C s dS rh r r� r r r r� [ s z Flag._sizeofc C s dS )Nz(io.read(1) != b'\x00')r r� r r r r� ^ s zFlag._emitparsec C s dS )Nz;((io.write(b'\x01') if obj else io.write(b'\x00')), obj)[1]r r� r r r r� a s zFlag._emitbuildc C s t |r dnddd�S )N�b1�u1r )r �_construct_renderr] r r r r r d s zFlag._emitfulltypeN) r r r r r� r� r� r� r� r r r r r r E s r c @ s e Zd ZdZdS )� EnumIntegerr� Nr r r r r r h s r c @ s, e Zd ZdZdd� Zdd� Zedd� �ZdS ) �EnumIntegerStringr� c C s d| j t�| �f S )Nz EnumIntegerString.new(%s, %s))�intvaluer] r� rX r r r r� p s zEnumIntegerString.__repr__c C s | j S r2 )r rX r r r �__int__s s zEnumIntegerString.__int__c C s t |�}| |_|S r2 )r r )r Z stringvalue�retr r r �newv s zEnumIntegerString.newN)r r r r r� r r[ r! r r r r r m s r c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )�Enuma� Translates unicode label names to subcon values, and vice versa. Parses integer subcon, then uses that value to lookup mapping dictionary. Returns an integer-convertible string (if mapping found) or an integer (otherwise). Building is a reversed process. Can build from an integer flag or string label. Size is same as subcon, unless it raises SizeofError. There is no default parameter, because if no mapping is found, it parses into an integer without error. This class supports enum module. See examples. This class supports exposing member labels as attributes, as integer-convertible strings. See examples. :param subcon: Construct instance, subcon to map to/from :param \*merge: optional, list of enum.IntEnum and enum.IntFlag instances, to merge labels and values from :param \*\*mapping: dict, mapping string names to values :raises MappingError: building from string but no mapping found Example:: >>> d = Enum(Byte, one=1, two=2, four=4, eight=8) >>> d.parse(b"\x01") 'one' >>> int(d.parse(b"\x01")) 1 >>> d.parse(b"\xff") 255 >>> int(d.parse(b"\xff")) 255 >>> d.build(d.one or "one" or 1) b'\x01' >>> d.one 'one' import enum class E(enum.IntEnum or enum.IntFlag): one = 1 two = 2 Enum(Byte, E) <--> Enum(Byte, one=1, two=2) FlagsEnum(Byte, E) <--> FlagsEnum(Byte, one=1, two=2) c sl t � �|� |D ]}|D ]}|j||j< qqdd� |�� D �| _dd� |�� D �| _dd� |�� D �| _d S )Nc S s i | ]\}}t �||�|�qS r �r r! r� r r r r� � rp z!Enum.__init__.<locals>.<dictcomp>c S s i | ]\}}|t �||��qS r r# r� r r r r� � rp c S s i | ]\}}||�qS r r r� r r r r� � rp )r r r� r� r� � encmapping� decmapping� ksymapping)r r� �merge�mapping�enum� enumentryr r r r � s z Enum.__init__c C s" || j v r| j| j | S t�d S r2 )r$ r% rQ r r r r � __getattr__� s zEnum.__getattr__c C s, z | j | W S ty& t|� Y S 0 d S r2 )r% rP r r= r r r r9 � s z Enum._decodec C sF z t |t�r|W S | j| W S ty@ td|f |d��Y n0 d S )Nz"building failed, no mapping for %rr7 )rA r� r$ rP r r= r r r r: � s z Enum._encodec C sB d|� � � �}|�|� dt| j�� �� d| j�|�� d|� d�S )N�factory_� = �reuse((z ), lambda x: z.get(x, EnumInteger(x)))�rj rw r5 r% r� r� r| r r r r� � s zEnum._emitparsec C sB d|� � � �}|�|� dt| j�� �� d|� d| j�|�� d�S )Nr, r- �reuse(z .get(obj, obj), lambda obj: (�))�rj rw r5 r$ r� r� r| r r r r� � s zEnum._emitbuildc C s d|� � }| j|j|< |S )Nzenum_%s)rj r& r} )r r r r� r r r r � s zEnum._emitprimitivetype) r r r r r r+ r9 r: r� r� r r r r r r r" } s + r" c @ s e Zd ZdZdd� ZdS )�BitwisableStringr� c C s t d�| |��S )Nz{}|{})r3 r r" r r r �__or__� s zBitwisableString.__or__N)r r r r r4 r r r r r3 � s r3 c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )� FlagsEnuma Translates unicode label names to subcon integer (sub)values, and vice versa. Parses integer subcon, then creates a Container, where flags define each key. Builds from a container by bitwise-oring of each flag if it matches a set key. Can build from an integer flag or string label directly, as well as | concatenations thereof (see examples). Size is same as subcon, unless it raises SizeofError. This class supports enum module. See examples. This class supports exposing member labels as attributes, as bitwisable strings. See examples. :param subcon: Construct instance, must operate on integers :param \*merge: optional, list of enum.IntEnum and enum.IntFlag instances, to merge labels and values from :param \*\*flags: dict, mapping string names to integer values :raises MappingError: building from object not like: integer string dict :raises MappingError: building from string but no mapping found Can raise arbitrary exceptions when computing | and & and value is non-integer. Example:: >>> d = FlagsEnum(Byte, one=1, two=2, four=4, eight=8) >>> d.parse(b"\x03") Container(one=True, two=True, four=False, eight=False) >>> d.build(dict(one=True,two=True)) b'\x03' >>> d.build(d.one|d.two or "one|two" or 1|2) b'\x03' import enum class E(enum.IntEnum or enum.IntFlag): one = 1 two = 2 Enum(Byte, E) <--> Enum(Byte, one=1, two=2) FlagsEnum(Byte, E) <--> FlagsEnum(Byte, one=1, two=2) c sJ t � �|� |D ]}|D ]}|j||j< qq|| _dd� |�� D �| _d S )Nc S s i | ]\}}||�qS r r r� r r r r� rp z&FlagsEnum.__init__.<locals>.<dictcomp>)r r r� r� �flagsr� � reverseflags)r r� r' r6 r) r* r r r r s zFlagsEnum.__init__c C s || j v rt|�S t�d S r2 )r6 r3 rQ r r r r r+ s zFlagsEnum.__getattr__c C s8 t � }d|_| j�� D ] \}}||@ |k|t|�< q|S �NT)r� Z _flagsenumr6 r� r3 )r r� r� r r; r� r� r r r r9 s zFlagsEnum._decodec C s� z�t |t�r|W S t |t�rPd}|�d�D ] }|�� }|r*|| j| O }q*|W S t |t�r�d}|�� D ]$\}}|�d�sf|rf|| j| O }qf|W S t d|f |d��W n$ t y� t d|f |d��Y n0 d S )Nr �|r z#building failed, unknown object: %rr7 z"building failed, unknown label: %r) rA r� r! �splitrk r6 r r� � startswithr rP )r r� r� r r6 r� r� r r r r: s( zFlagsEnum._encodec C s0 d| j �|�� dd�dd� | j�� D ��� d�S )Nr. z), lambda x: Container(r� c s s( | ] \}}|� d |� d|� d�V qdS )z =bool(x & z == rS Nr r� r r r rs 1 rp z'FlagsEnum._emitparse.<locals>.<genexpr>r1 )r� r� rv r6 r� r� r r r r� 0 s zFlagsEnum._emitparsec C sX | j �� d }g }t|�D ]8}d|> }| j�|d| �}|�t|dt|�dd�� q|S )Nr^ rP z unknown_%sr r )r� r �docr )r� r� �ranger7 �getrw r �hex)r r r Z bitstotalr �ir� r� r r r r 3 s zFlagsEnum._emitseq) r r r r r r+ r9 r: r� r r r r r r r5 � s & r5 c s@ e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Z� Z S ) �Mappinga\ Adapter that maps objects to other objects. Translates objects after parsing and before building. Can for example, be used to translate between enum objects and strings, but Enum class supports enum module already and is recommended. :param subcon: Construct instance :param mapping: dict, for encoding (building) mapping, the reversed is used for parsing mapping :raises MappingError: parsing or building but no mapping found Example:: >>> x = object >>> d = Mapping(Byte, {x:0}) >>> d.parse(b"\x00") x >>> d.build(x) b'\x00' c s* t � �|� dd� |�� D �| _|| _d S )Nc S s i | ]\}}||�qS r r r� r r r r� R rp z$Mapping.__init__.<locals>.<dictcomp>)r r r� r% r$ )r r� r( r r r r P s zMapping.__init__c C s: z | j | W S ttfy4 td|f |d��Y n0 d S )Nz*parsing failed, no decoding mapping for %rr7 )r% rP r3 r r= r r r r9 U s zMapping._decodec C s: z | j | W S ttfy4 td|f |d��Y n0 d S )Nz+building failed, no encoding mapping for %rr7 )r$ rP r3 r r= r r r r: [ s zMapping._encodec C s@ d|� � � �}|�|� dt| j�� �� |� d| j�|�� d�S )Nr, r- �[�]r/ r| r r r r� a s zMapping._emitparsec C sB d|� � � �}|�|� dt| j�� �� d|� d| j�|�� d�S )Nr, r- r0 z[obj], lambda obj: (r1 r2 r| r r r r� f s zMapping._emitbuildr r r r r rA = s rA c sX e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dd� Z � Z S )r& a Sequence of usually named constructs, similar to structs in C. The members are parsed and build in the order they are defined. If a member is anonymous (its name is None) then it gets parsed and the value discarded, or it gets build from nothing (from None). Some fields do not need to be named, since they are built without value anyway. See: Const Padding Check Error Pass Terminated Seek Tell for examples of such fields. Operator + can also be used to make Structs (although not recommended). Parses into a Container (dict with attribute and key access) where keys match subcon names. Builds from a dict (not necessarily a Container) where each member gets a value from the dict matching the subcon name. If field has build-from-none flag, it gets build even when there is no matching entry in the dict. Size is the sum of all subcon sizes, unless any subcon raises SizeofError. This class does context nesting, meaning its members are given access to a new dictionary where the "_" entry points to the outer context. When parsing, each member gets parsed and subcon parse return value is inserted into context under matching key only if the member was named. When building, the matching entry gets inserted into context before subcon gets build, and if subcon build returns a new value (not None) that gets replaced in the context. This class exposes subcons as attributes. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) by accessing the struct attributes, under same name. Also note that compiler does not support this feature. See examples. This class exposes subcons in the context. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) within other inlined fields using the context. Note that you need to use a lambda (`this` expression is not supported). Also note that compiler does not support this feature. See examples. This class supports stopping. If :class:`~construct.core.StopIf` field is a member, and it evaluates its lambda as positive, this class ends parsing or building as successful without processing further fields. :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises KeyError: building a subcon but found no corresponding key in dictionary Example:: >>> d = Struct("num"/Int8ub, "data"/Bytes(this.num)) >>> d.parse(b"\x04DATA") Container(num=4, data=b"DATA") >>> d.build(dict(num=4, data=b"DATA")) b"\x04DATA" >>> d = Struct(Const(b"MZ"), Padding(2), Pass, Terminated) >>> d.build({}) b'MZ\x00\x00' >>> d.parse(_) Container() >>> d.sizeof() 4 >>> d = Struct( ... "animal" / Enum(Byte, giraffe=1), ... ) >>> d.animal.giraffe 'giraffe' >>> d = Struct( ... "count" / Byte, ... "data" / Bytes(lambda this: this.count - this._subcons.count.sizeof()), ... ) >>> d.build(dict(count=3, data=b"12")) b'\x0312' Alternative syntax (not recommended): >>> ("a"/Byte + "b"/Byte + "c"/Byte + "d"/Byte) Alternative syntax, but requires Python 3.6 or any PyPy: >>> Struct(a=Byte, b=Byte, c=Byte, d=Byte) c sZ t � �� t|�tdd� |�� D �� | _tdd� | jD ��| _tdd� | jD ��| _d S )Nc s s | ]\}}|| V qd S r2 r r� r r r rs � rp z"Struct.__init__.<locals>.<genexpr>c s s | ]}|j r|j |fV qd S r2 �r� �rm r� r r r rs � rp c s s | ] }|j V qd S r2 �r� rE r r r rs � rp � r r rs r� r' r� �_subcons�allr� �r r' � subconskwr r r r � s zStruct.__init__c C s || j v r| j | S t�d S r2 �rH rQ r r r r r+ � s zStruct.__getattr__c C s� t � }||_t ||jd |j|j|j| j||�dd �d� }|j�d|�|_ | j D ]J}z,|� |||�}|j r||||j < |||j < W qN t y� Y q�Y qN0 qN|S �N�_index� r r� �_rootr� r� r� rH �_iorN rP )r� rQ r� r� r� r� rH r> r rP r' r� r� r* �r r; r� r r� r� �subobjr r r r� � s , z Struct._parsec C s� |d u rt � }t ||jd |j|j|j| j||�dd �d� }|j�d|�|_|� |� | j D ]r}zT|j rv|�|j d �}n ||j }|j r�|||j < |� ||||�}|j r�|||j < W qZ ty� Y q�Y qZ0 qZ|S rM �r� r� r� r� r� rH r> r rP r� r' r� r� r� r* �r r� r; r� r r� rS r< r r r r� � s$ , z Struct._buildc s� t � � jd � j� j� j| jd � �dd �d� � � j�d� �� _z t � �fdd�| j D ��W S t t fyz t d�d��Y n0 d S )NrN rO rP c 3 s | ]}|� � ��V qd S r2 r� rE �r� r r r rs � rp z!Struct._sizeof.<locals>.<genexpr>rO r7 �r� r� r� r� r� rH r> r rP �sumr' rP rQ r r� r rV r r� � s , zStruct._sizeofc C s� d|� � � �}d|� d�}| jD ]B}|d|jrLdt|j�� dt|j�� d�nd� |�|�� d �7 }q |d 7 }|�|� |� d �S ) NZ parse_struct_� def aR (io, this): result = Container() this = Container(_ = this, _params = this['_params'], _root = None, _parsing = True, _building = False, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) try: � zresult[z ] = this[�] = r � �� pass except StopFieldError: pass return result � (io, this))rj r' r� r5 r� rw �r r� r} rx r� r r r r� � s � &�� zStruct._emitparsec C s� d|� � � �}d|� d�}| jD ]�}|d|jr@dt|j�� d�ndt|j�� d�� d|jrld t|j�� d �nd � d|jr�d t|j�� d �nd � |�|�� d �7 }q |d7 }|�|� |� d�S )NZ build_struct_rY au (obj, io, this): this = Container(_ = this, _params = this['_params'], _root = None, _parsing = False, _building = True, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) this.update(obj) try: objdict = obj rZ �obj = objdict.get(�, None)�obj = objdict[rC �this[�] = objr r[ r\ z~ pass except StopFieldError: pass return this �(obj, io, this)�rj r' r� r5 r� r� rw r_ r r r r� � s" � (���� zStruct._emitbuildc s � �fdd�| j D �S )Nc s g | ]}|� �� ��qS r rh rE �r r r r ro rp z#Struct._emitseq.<locals>.<listcomp>�r' r r rg r r s zStruct._emitseq� r r r r r r+ r� r� r� r� r� r r r r r r r& o s : r& c sX e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dd� Z � Z S )r, a Sequence of usually un-named constructs. The members are parsed and build in the order they are defined. If a member is named, its parsed value gets inserted into the context. This allows using members that refer to previous members. Operator >> can also be used to make Sequences (although not recommended). Parses into a ListContainer (list with pretty-printing) where values are in same order as subcons. Builds from a list (not necessarily a ListContainer) where each subcon is given the element at respective position. Size is the sum of all subcon sizes, unless any subcon raises SizeofError. This class does context nesting, meaning its members are given access to a new dictionary where the "_" entry points to the outer context. When parsing, each member gets parsed and subcon parse return value is inserted into context under matching key only if the member was named. When building, the matching entry gets inserted into context before subcon gets build, and if subcon build returns a new value (not None) that gets replaced in the context. This class exposes subcons as attributes. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) by accessing the struct attributes, under same name. Also note that compiler does not support this feature. See examples. This class exposes subcons in the context. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) within other inlined fields using the context. Note that you need to use a lambda (`this` expression is not supported). Also note that compiler does not support this feature. See examples. This class supports stopping. If :class:`~construct.core.StopIf` field is a member, and it evaluates its lambda as positive, this class ends parsing or building as successful without processing further fields. :param \*subcons: Construct instances, list of members, some can be named :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises KeyError: building a subcon but found no corresponding key in dictionary Example:: >>> d = Sequence(Byte, Float32b) >>> d.build([0, 1.23]) b'\x00?\x9dp\xa4' >>> d.parse(_) [0, 1.2300000190734863] # a ListContainer >>> d = Sequence( ... "animal" / Enum(Byte, giraffe=1), ... ) >>> d.animal.giraffe 'giraffe' >>> d = Sequence( ... "count" / Byte, ... "data" / Bytes(lambda this: this.count - this._subcons.count.sizeof()), ... ) >>> d.build([3, b"12"]) b'\x0312' Alternative syntax (not recommended): >>> (Byte >> "Byte >> "c"/Byte >> "d"/Byte) Alternative syntax, but requires Python 3.6 or any PyPy: >>> Sequence(a=Byte, b=Byte, c=Byte, d=Byte) c sZ t � �� t|�tdd� |�� D �� | _tdd� | jD ��| _tdd� | jD ��| _d S )Nc s s | ]\}}|| V qd S r2 r r� r r r rs I rp z$Sequence.__init__.<locals>.<genexpr>c s s | ]}|j r|j |fV qd S r2 rD rE r r r rs J rp c s s | ] }|j V qd S r2 rF rE r r r rs K rp rG rJ r r r r G s zSequence.__init__c C s || j v r| j | S t�d S r2 rL r r r r r+ M s zSequence.__getattr__c C s� t � }t||jd |j|j|j| j||�dd �d� }|j�d|�|_ | j D ]J}z,|� |||�}|� |� |j rv|||j < W qH ty� Y q�Y qH0 qH|S rM )� ListContainerr� r� r� r� r� rH r> r rP r' r� rw r� r* rR r r r r� R s , zSequence._parsec C s� |d u r t dd� | jD ��}t||jd |j|j|j| j||�dd �d� }|j �d|�|_ t |�}t � }t | j�D ]h\}}zFt |�} |jr�| ||j< |�| |||�} |�| � |jr�| ||j< W qp ty� Y q�Y qp0 qp|S )Nc S s g | ]}d �qS r2 r rE r r r ro b rp z#Sequence._build.<locals>.<listcomp>rN rO rP )rj r' r� r� r� r� r� rH r> r rP �iter� enumerate�nextr� r� rw r* ) r r� r; r� r Zobjiter�retlistr@ r� rS r< r r r r� ` s$ , zSequence._buildc s� t � � jd � j� j� j| jd � �dd �d� � � j�d� �� _z t � �fdd�| j D ��W S t t fyz t d�d��Y n0 d S )NrN rO rP c 3 s | ]}|� � ��V qd S r2 r� rE rV r r rs z rp z#Sequence._sizeof.<locals>.<genexpr>rO r7 rW r� r rV r r� v s , zSequence._sizeofc C st d|� � � �}d|� d�}| jD ]6}|d|�|�� d�7 }|jr |dt|j�� d�7 }q |d7 }|�|� |� d �S ) NZparse_sequence_rY aV (io, this): result = ListContainer() this = Container(_ = this, _params = this['_params'], _root = None, _parsing = True, _building = False, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) try: z# result.append(�) z this[� ] = result[-1] r] r^ )rj r' r� r� r5 rw r_ r r r r� ~ s � � � zSequence._emitparsec C s� d|� � � �}d|� d�}| jD ]f}|dd� d|jrFdt|j�� d�nd� dd � |�|�� dd � d|jrzdt|j�� d �nd� d � 7 }q |d 7 }|�|� |� d�S )NZbuild_sequence_rY a� (obj, io, this): this = Container(_ = this, _params = this['_params'], _root = None, _parsing = False, _building = True, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) try: objiter = iter(obj) retlist = ListContainer() rZ zobj = next(objiter)rc rd r zx = zretlist.append(x)z] = xr\ z� pass except StopFieldError: pass return retlist re )rj r' r� r5 r� rw r_ r r r r� � s* � ������ zSequence._emitbuildc s � �fdd�| j D �S )Nc s g | ]}|� �� ��qS r rh rE rg r r ro � rp z%Sequence._emitseq.<locals>.<listcomp>rh r r rg r r � s zSequence._emitseqri r r r r r, s 0 r, c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )r/ a� Homogenous array of elements, similar to C# generic T[]. Parses into a ListContainer (a list). Parsing and building processes an exact amount of elements. If given list has more or less than count elements, raises RangeError. Size is defined as count multiplied by subcon size, but only if subcon is fixed size. Operator [] can be used to make Array instances (recommended syntax). :param count: integer or context lambda, strict amount of elements :param subcon: Construct instance, subcon to process individual elements :param discard: optional, bool, if set then parsing returns empty list :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises RangeError: specified count is not valid :raises RangeError: given object has different length than specified count Can propagate any exception from the lambdas, possibly non-ConstructError. Example:: >>> d = Array(5, Byte) or Byte[5] >>> d.build(range(5)) b'\x00\x01\x02\x03\x04' >>> d.parse(_) [0, 1, 2, 3, 4] Fc s t � �|� || _|| _d S r2 )r r r0 �discard)r r0 r� rq r r r r � s zArray.__init__c C sh t | j|�}d|ks&td|f |d��| j}t� }t|�D ](}||_| j�|||�}|s:|� |� q:|S )Nr �invalid count %sr7 ) r� r0 r rq rj r= rN r� r� rw ) r r; r� r r0 rq r� r@ r� r r r r� � s z Array._parsec C s� t | j|�}d|ks&td|f |d��t|�|ksJtd|t|�f |d��| j}t� }t|�D ].\}} ||_| j� | |||�} |s^|� | � q^|S �Nr rr r7 z expected %d elements, found %d) r� r0 r r: rq rj rl rN r� r� rw ) r r� r; r� r r0 rq rn r@ r� r< r r r r� � s z Array._buildc C sF zt | j|�}W n" ttfy2 td|d��Y n0 || j�||� S rN )r� r0 rP rQ r r� r� �r r� r r0 r r r r� � s z Array._sizeofc C s d| j �|�� d| j� d�S )NzListContainer((z) for i in range(r1 )r� r� r0 r� r r r r� � s zArray._emitparsec C s d| j �|�� d| j� d�S )Nz)ListContainer(reuse(obj[i], lambda obj: (z)) for i in range(r1 )r� r� r0 r� r r r r� s zArray._emitbuildc C s t | j�||�d| jd�S )N�expr)r �repeat� repeat_expr)r r� r r0 r r r r r s zArray._emitfulltype)FrY r r r r r/ � s r/ c sB e Zd ZdZd � fdd� Zdd� Zdd� Zd d � Zd d � Z� Z S )� GreedyRangeag Homogenous array of elements, similar to C# generic IEnumerable<T>, but works with unknown count of elements by parsing until end of stream. Parses into a ListContainer (a list). Parsing stops when an exception occured when parsing the subcon, either due to EOF or subcon format not being able to parse the data. Either way, when GreedyRange encounters either failure it seeks the stream back to a position after last successful subcon parsing. Builds from enumerable, each element as-is. Size is undefined. This class supports stopping. If :class:`~construct.core.StopIf` field is a member, and it evaluates its lambda as positive, this class ends parsing or building as successful without processing further fields. :param subcon: Construct instance, subcon to process individual elements :param discard: optional, bool, if set then parsing returns empty list :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable Can propagate any exception from the lambdas, possibly non-ConstructError. Example:: >>> d = GreedyRange(Byte) >>> d.build(range(8)) b'\x00\x01\x02\x03\x04\x05\x06\x07' >>> d.parse(_) [0, 1, 2, 3, 4, 5, 6, 7] Fc s t � �|� || _d S r2 )r r rq )r r� rq r r r r s zGreedyRange.__init__c C s� | j }t� }z@t�� D ]2}||_t||�}| j�|||�}|s|�|� qW nB t y^ Y n2 t yp � Y n t y� t ||d|� Y n0 |S r` ) rq rj � itertoolsr0 rN rJ r� r� rw r* r$ r9 rH ) r r; r� r rq r� r@ rM r� r r r r� $ s zGreedyRange._parsec C sb | j }zDt� }t|�D ].\}}||_| j�||||�} |s|�| � q|W S ty\ Y n0 d S r2 )rq rj rl rN r� r� rw r* ) r r� r; r� r rq rn r@ r� r< r r r r� 6 s zGreedyRange._buildc C s t |d��d S rE r� r� r r r r� C s zGreedyRange._sizeofc C s t | j�||�dd�S )NZeos)r rv )r r� r r r r r r F s zGreedyRange._emitfulltype)F� r r r r r r� r� r� r r r r r r rx s rx c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )� RepeatUntila� Homogenous array of elements, similar to C# generic IEnumerable<T>, that repeats until the predicate indicates it to stop. Note that the last element (that predicate indicated as True) is included in the return list. Parse iterates indefinately until last element passed the predicate. Build iterates indefinately over given list, until an element passed the precicate (or raises RepeatError if no element passed it). Size is undefined. :param predicate: lambda that takes (obj, list, context) and returns True to break or False to continue (or a truthy value) :param subcon: Construct instance, subcon used to parse and build each element :param discard: optional, bool, if set then parsing returns empty list :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises RepeatError: consumed all elements in the stream but neither passed the predicate Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = RepeatUntil(lambda x,lst,ctx: x > 7, Byte) >>> d.build(range(20)) b'\x00\x01\x02\x03\x04\x05\x06\x07\x08' >>> d.parse(b"\x01\xff\x02") [1, 255] >>> d = RepeatUntil(lambda x,lst,ctx: lst[-2:] == [0,0], Byte) >>> d.parse(b"\x01\x00\x00\xff") [1, 0, 0] Fc s t � �|� || _|| _d S r2 )r r � predicaterq )r r| r� rq r r r r f s zRepeatUntil.__init__c sp | j � | j}t� �s � fdd�� t� }t�� D ]<}||_| j�|||�}|sV|� |� � |||�r.| S q.d S )Nc s � S r2 r �Z_1Z_2Z_3�r| r r r� o rp z$RepeatUntil._parse.<locals>.<lambda>) r| rq r� rj ry r0 rN r� r� rw )r r; r� r rq r� r@ r� r r~ r r� k s zRepeatUntil._parsec s� | j � | j}t� �s � fdd�� t� }t� }t|�D ]H\}} ||_| j�| |||�} |sl|�| � |�| � � | ||�r4 q�q4t d|d��|S )Nc s � S r2 r r} r~ r r r� } rp z$RepeatUntil._build.<locals>.<lambda>z3expected any item to match predicate, when buildingr7 ) r| rq r� rj rl rN r� r� rw r ) r r� r; r� r rq Z partiallistrn r@ r� r< r r~ r r� y s zRepeatUntil._buildc C s t d|d��d S )Nz4cannot calculate size, amount depends on actual datar7 r� r� r r r r� � s zRepeatUntil._sizeofc C sL d|� � � �}d|� d| j�|�� d| j� d| j� d� }|�|� |� d�S )NZparse_repeatuntil_rY zk(io, this): list_ = ListContainer() while True: obj_ = z if not (zF): list_.append(obj_) if (�0): return list_ r^ )rj r� r� rq r| rw �r r� r} rx r r r r� � s � ��� zRepeatUntil._emitparsec C sD d|� � � �}d|� d| j�|�� d| j� d�}|�|� |� d�S )NZbuild_repeatuntil_rY z�(obj, io, this): objiter = iter(obj) list_ = ListContainer() while True: obj_ = reuse(next(objiter), lambda obj: zA) list_.append(obj_) if (r re )rj r� r� r| rw r� r r r r� � s � �� zRepeatUntil._emitbuildc C s& t | j�||�dt| j��dd�d�S )NZuntilZobj_r )r rv Z repeat_until)r r� r r5 r| r� r r r r r � s zRepeatUntil._emitfulltype)FrY r r r r r{ J s r{ c sj e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z dd� Z dd� Z dd� Z � ZS )r� a' Special wrapper that allows a Struct (or other similar class) to see a field as having a name (or a different name) or having a parsed hook. Library classes do not have names (its None). Renamed does not change a field, only wraps it like a candy with a label. Used internally by / and * operators. Also this wrapper is responsible for building a path info (a chain of names) that gets attached to error message when parsing, building, or sizeof fails. Fields that are not named do not appear in the path string. Parsing building and size are deferred to subcon. :param subcon: Construct instance :param newname: optional, string :param newdocs: optional, string :param newparsed: optional, lambda Example:: >>> "number" / Int32ub <Renamed: number> Nc s@ t � �|� |r|n|j| _|r$|n|j| _|r4|n|j| _d S r2 )r r r� r� r� )r r� r r r r r r r � s zRenamed.__init__c C s t | j|�S r2 )r� r� r r r r r+ � s zRenamed.__getattr__c C s |d| j f 7 }| j�|||�S �Nz -> %s)r� r� r� r� r r r r� � s zRenamed._parsec C s" |d| j f 7 }| j�||||�S r� )r� r� r� r� r r r r� � s zRenamed._buildc C s |d| j f 7 }| j�||�S r� )r� r� r� r� r r r r� � s zRenamed._sizeofc C s | j �|�S r2 �r� r� r� r r r r� � s zRenamed._emitparsec C s | j �|�S r2 )r� r� r� r r r r� � s zRenamed._emitbuildc C s | j �||�S r2 �r� r r r r r r � s zRenamed._emitseqc C s | j �||�S r2 �r� r r r r r r � s zRenamed._emitprimitivetypec C sF t � }| jr|j| jd� |�| j�||�� | jrB|j| jd� |S )Nr )r< )r r� r� r� r r� )r r r �rr r r r � s zRenamed._emitfulltype)NNN)r r r r r r+ r� r� r� r� r� r r r r r r r r r� � s r� c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )�Consta� Field enforcing a constant. It is used for file signatures, to validate that the given pattern exists. Data in the stream must strictly match the specified value. Note that a variable sized subcon may still provide positive verification. Const does not consume a precomputed amount of bytes, but depends on the subcon to read the appropriate amount (eg. VarInt is acceptable). Whatever subcon parses into, gets compared against the specified value. Parses using subcon and return its value (after checking). Builds using subcon from nothing (or given object, if not None). Size is the same as subcon, unless it raises SizeofError. :param value: expected value, usually a bytes literal :param subcon: optional, Construct instance, subcon used to build value from, assumed to be Bytes if value parameter was a bytes literal :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises ConstError: parsed data does not match specified value, or building from wrong value :raises StringError: building from non-bytes value, perhaps unicode Example:: >>> d = Const(b"IHDR") >>> d.build(None) b'IHDR' >>> d.parse(b"JPEG") construct.core.ConstError: expected b'IHDR' but parsed b'JPEG' >>> d = Const(255, Int32ul) >>> d.build(None) b'\xff\x00\x00\x00' Nc sN |d u r2t |t�s&tdt|�� d���tt|��}t� �|� || _d| _ d S )Nzgiven non-bytes value z, perhaps unicode?T) rA rB r r5 rJ r: r r r� r� )r r� r� r r r r s zConst.__init__c C s@ | j �|||�}|| jks<tdt| j�� dt|�� �|d��|S )Nzparsing expected z but parsed r7 )r� r� r� r! r5 r� r r r r� s "z Const._parsec C sD |d | j fvr0tdt| j �� dt|�� �|d��| j�| j |||�S )Nzbuilding expected None or z but got r7 )r� r! r5 r� r� r� r r r r� s "z Const._buildc C s | j �||�S r2 r7 r� r r r r� % s z Const._sizeofc C s* |� d� d| j�|�� dt| j�� d�S )Nz� def parse_const(value, expected): if not value == expected: raise ConstError return value z parse_const(r� rS )rw r� r� r5 r� r� r r r r� ( s zConst._emitparsec C sN t | jt�r*dt| j�� dt| j�� d�S dt| j�� d| j�|�� d�S d S )Nr~ r� z)[1]r0 z, lambda obj: rS )rA r� r^ r5 r� r� r� r r r r� 0 s zConst._emitbuildc C s | j �| j�}tt|�d�S )N)rS )r� r� r� r rs )r r r r= r r r r 6 s zConst._emitfulltype)NrY r r r r r� � s r� c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�Computeda� Field computing a value from the context dictionary or some outer source like os.urandom or random module. Underlying byte stream is unaffected. The source can be non-deterministic. Parsing and Building return the value returned by the context lambda (although a constant value can also be used). Size is defined as 0 because parsing and building does not consume or produce bytes into the stream. :param func: context lambda or constant value Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Struct( ... "width" / Byte, ... "height" / Byte, ... "total" / Computed(this.width * this.height), ... ) >>> d.build(dict(width=4,height=5)) b'\x04\x05' >>> d.parse(b"12") Container(width=49, height=50, total=2450) >>> d = Computed(7) >>> d.parse(b"") 7 >>> d = Computed(lambda ctx: 7) >>> d.parse(b"") 7 >>> import os >>> d = Computed(lambda ctx: os.urandom(10)) >>> d.parse(b"") b'\x98\xc2\xec\x10\x07\xf5\x8e\x98\xc2\xec' c s t � �� || _d| _d S r8 �r r �funcr� �r r� r r r r ] s zComputed.__init__c C s t | j�r| �|�S | jS r2 �r� r� r� r r r r� b s zComputed._parsec C s t | j�r| �|�S | jS r2 r� r� r r r r� e s zComputed._buildc C s dS r` r r� r r r r� h s zComputed._sizeofc C s t | j�S r2 �r5 r� r� r r r r� k s zComputed._emitparsec C s t | j�S r2 r� r� r r r r� n s zComputed._emitbuild� r r r r r r� r� r� r� r� r r r r r r� ; s ! r� c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) �Indexa� Indexes a field inside outer :class:`~construct.core.Array` :class:`~construct.core.GreedyRange` :class:`~construct.core.RepeatUntil` context. Note that you can use this class, or use `this._index` expression instead, depending on how its used. See the examples. Parsing and building pulls _index key from the context. Size is 0 because stream is unaffected. :raises IndexFieldError: did not find either key in context Example:: >>> d = Array(3, Index) >>> d.parse(b"") [0, 1, 2] >>> d = Array(3, Struct("i" / Index)) >>> d.parse(b"") [Container(i=0), Container(i=1), Container(i=2)] >>> d = Array(3, Computed(this._index+1)) >>> d.parse(b"") [1, 2, 3] >>> d = Array(3, Struct("i" / Computed(this._._index+1))) >>> d.parse(b"") [Container(i=1), Container(i=2), Container(i=3)] c s t � �� d| _d S r8 �r r r� rX r r r r � s zIndex.__init__c C s |� dd �S �NrN �r> r� r r r r� � s z Index._parsec C s |� dd �S r� r� r� r r r r� � s z Index._buildc C s dS r` r r� r r r r� � s z Index._sizeof� r r r r r r� r� r� r r r r r r� r s r� c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )�Rebuilda� Field where building does not require a value, because the value gets recomputed when needed. Comes handy when building a Struct from a dict with missing keys. Useful for length and count fields when :class:`~construct.core.Prefixed` and :class:`~construct.core.PrefixedArray` cannot be used. Parsing defers to subcon. Building is defered to subcon, but it builds from a value provided by the context lambda (or constant). Size is the same as subcon, unless it raises SizeofError. Difference between Default and Rebuild, is that in first the build value is optional and in second the build value is ignored. :param subcon: Construct instance :param func: context lambda or constant value :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Struct( ... "count" / Rebuild(Byte, len_(this.items)), ... "items" / Byte[this.count], ... ) >>> d.build(dict(items=[1,2,3])) b'\x03\x01\x02\x03' c s t � �|� || _d| _d S r8 r� )r r� r� r r r r � s zRebuild.__init__c C s t | j|�}| j�||||�S r2 )r� r� r� r� r� r r r r� � s zRebuild._buildc C s | j �|�S r2 r� r� r r r r� � s zRebuild._emitparsec C s dt | j�� d| j�|�� d�S )Nr0 z, lambda obj: (r1 )r5 r� r� r� r� r r r r� � s zRebuild._emitbuildc C s | j �||�S r2 r� r r r r r � s zRebuild._emitseqc C s | j �||�S r2 r� r r r r r � s zRebuild._emitprimitivetypec C s | j �||�S r2 �r� r r r r r r � s zRebuild._emitfulltype� r r r r r r� r� r� r r r r r r r r r� � s r� c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )�Defaulta3 Field where building does not require a value, because the value gets taken from default. Comes handy when building a Struct from a dict with missing keys. Parsing defers to subcon. Building is defered to subcon, but it builds from a default (if given object is None) or from given object. Building does not require a value, but can accept one. Size is the same as subcon, unless it raises SizeofError. Difference between Default and Rebuild, is that in first the build value is optional and in second the build value is ignored. :param subcon: Construct instance :param value: context lambda or constant value :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Struct( ... "a" / Default(Byte, 0), ... ) >>> d.build(dict(a=1)) b'\x01' >>> d.build(dict()) b'\x00' c s t � �|� || _d| _d S r8 )r r r� r� )r r� r� r r r r � s zDefault.__init__c C s* |d u rt | j|�n|}| j�||||�S r2 )r� r� r� r� r� r r r r� � s zDefault._buildc C s | j �|�S r2 r� r� r r r r� � s zDefault._emitparsec C s dt | j�� d| j�|�� d�S )Nr0 z' if obj is None else obj, lambda obj: (r1 )r5 r� r� r� r� r r r r� � s zDefault._emitbuildc C s | j �||�S r2 r� r r r r r � s zDefault._emitseqc C s | j �||�S r2 r� r r r r r � s zDefault._emitprimitivetypec C s | j �||�S r2 r� r r r r r � s zDefault._emitfulltyper� r r r r r� � s r� c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�Checka Checks for a condition, and raises CheckError if the check fails. Parsing and building return nothing (but check the condition). Size is 0 because stream is unaffected. :param func: bool or context lambda, that gets run on parsing and building :raises CheckError: lambda returned false Can propagate any exception from the lambda, possibly non-ConstructError. Example:: Check(lambda ctx: len(ctx.payload.data) == ctx.payload_len) Check(len_(this.payload.data) == this.payload_len) c s t � �� || _d| _d S r8 r� r� r r r r s zCheck.__init__c C s t | j|�}|s td|d��d S )Nzcheck failed during parsingr7 �r� r� r# )r r; r� r �passedr r r r� s z Check._parsec C s t | j|�}|s td|d��d S )Nz check failed during buildingr7 r� )r r� r; r� r r� r r r r� s z Check._buildc C s dS r` r r� r r r r� " s z Check._sizeofc C s |� d� dt| j�� d�S )Nzd def parse_check(condition): if not condition: raise CheckError z parse_check(rS �rw r5 r� r� r r r r� % s zCheck._emitparsec C s |� d� dt| j�� d�S )Nzd def build_check(condition): if not condition: raise CheckError z build_check(rS r� r� r r r r� , s zCheck._emitbuildr� r r r r r� s r� c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�Errorag Raises ExplicitError, unconditionally. Parsing and building always raise ExplicitError. Size is undefined. :raises ExplicitError: unconditionally, on parsing and building Example:: >>> d = Struct("num"/Byte, Error) >>> d.parse(b"data...") construct.core.ExplicitError: Error field was activated during parsing c s t � �� d| _d S r8 r� rX r r r r D s zError.__init__c C s t d|d��d S )Nz(Error field was activated during parsingr7 �r$ r� r r r r� H s z Error._parsec C s t d|d��d S )Nz)Error field was activated during buildingr7 r� r� r r r r� K s z Error._buildc C s t d|d��d S )NzDError does not have size, because it interrupts parsing and buildingr7 r� r� r r r r� N s z Error._sizeofc C s |� d� dS )NzL def parse_error(): raise ExplicitError z parse_error()�rw r� r r r r� Q s zError._emitparsec C s |� d� dS )NzL def build_error(): raise ExplicitError z build_error()r� r� r r r r� X s zError._emitbuildr� r r r r r� 4 s r� c sX e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dd� Z � Z S )� FocusedSeqa Allows constructing more elaborate "adapters" than Adapter class. Parse does parse all subcons in sequence, but returns only the element that was selected (discards other values). Build does build all subcons in sequence, where each gets build from nothing (except the selected subcon which is given the object). Size is the sum of all subcon sizes, unless any subcon raises SizeofError. This class does context nesting, meaning its members are given access to a new dictionary where the "_" entry points to the outer context. When parsing, each member gets parsed and subcon parse return value is inserted into context under matching key only if the member was named. When building, the matching entry gets inserted into context before subcon gets build, and if subcon build returns a new value (not None) that gets replaced in the context. This class exposes subcons as attributes. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) by accessing the struct attributes, under same name. Also note that compiler does not support this feature. See examples. This class exposes subcons in the context. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) within other inlined fields using the context. Note that you need to use a lambda (`this` expression is not supported). Also note that compiler does not support this feature. See examples. This class is used internally to implement :class:`~construct.core.PrefixedArray`. :param parsebuildfrom: string name or context lambda, selects a subcon :param \*subcons: Construct instances, list of members, some can be named :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises UnboundLocalError: selector does not match any subcon Can propagate any exception from the lambda, possibly non-ConstructError. Excample:: >>> d = FocusedSeq("num", Const(b"SIG"), "num"/Byte, Terminated) >>> d.parse(b"SIG\xff") 255 >>> d.build(255) b'SIG\xff' >>> d = FocusedSeq("animal", ... "animal" / Enum(Byte, giraffe=1), ... ) >>> d.animal.giraffe 'giraffe' >>> d = FocusedSeq("count", ... "count" / Byte, ... "data" / Padding(lambda this: this.count - this._subcons.count.sizeof()), ... ) >>> d.build(4) b'\x04\x00\x00\x00' PrefixedArray <--> FocusedSeq("items", "count" / Rebuild(lengthfield, len_(this.items)), "items" / subcon[this.count], ) c sJ t � �� || _t|�tdd� |�� D �� | _tdd� | jD ��| _d S )Nc s s | ]\}}|| V qd S r2 r r� r r r rs � rp z&FocusedSeq.__init__.<locals>.<genexpr>c s s | ]}|j r|j |fV qd S r2 rD rE r r r rs � rp )r r �parsebuildfromrs r� r' r� rH )r r� r' rK r r r r � s zFocusedSeq.__init__c C s || j v r| j | S t�d S r2 rL r r r r r+ � s zFocusedSeq.__getattr__c C s� t ||jd |j|j|j| j||�dd �d� }|j�d|�|_t | j |�}t | j �D ]4\}}|� |||�}|jrx|||j< |j|krR|}qR|S rM )r� r� r� r� r� rH r> r rP r� r� rl r' r� r� ) r r; r� r r� r@ r� �parseret�finalretr r r r� � s , zFocusedSeq._parsec C s� t ||jd |j|j|j| j||�dd �d� }|j�d|�|_t | j |�}|||< t | j �D ]D\}}|� |j|krt|nd |||�}|jr�|||j< |j|krZ|} qZ| S rM )r� r� r� r� r� rH r> r rP r� r� rl r' r� r� ) r r� r; r� r r� r@ r� r< r� r r r r� � s , zFocusedSeq._buildc s� t � � jd � j� j� j| jd � �dd �d� � � j�d� �� _z t � �fdd�| j D ��W S t t fyz t d�d��Y n0 d S )NrN rO rP c 3 s | ]}|� � ��V qd S r2 r� rE rV r r rs � rp z%FocusedSeq._sizeof.<locals>.<genexpr>rO r7 rW r� r rV r r� � s , zFocusedSeq._sizeofc C s� d|� � � �}d|� d�}| jD ]6}|d|�|�� d�7 }|jr |dt|j�� d�7 }q |dt| j�� d �7 }|�|� |� d �S ) NZparse_focusedseq_rY a4 (io, this): result = [] this = Container(_ = this, _params = this['_params'], _root = None, _parsing = True, _building = False, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) z result.append(ro z this[rp z return this[z ] r^ )rj r' r� r� r5 r� rw r_ r r r r� � s" � � � � zFocusedSeq._emitparsec C s� d|� � � �}d|� dt| j�� d�}| jD ]p}|dd|j| jkrFdnd� �� dd � |�|�� d|jrxd t|j�� d �nd � d|j| jkr�d nd � � d� 7 }q,|d7 }|�|� |� d�S )NZbuild_focusedseq_rY aC (obj, io, this): this = Container(_ = this, _params = this['_params'], _root = None, _parsing = False, _building = True, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) try: this[z3] = obj finalobj = obj rZ zobj = Zfinalobj�Nonez buildret = rc z ] = buildretr zfinalret = buildretr\ z� pass except StopFieldError: pass return finalret re )rj r5 r� r' r� r� rw r_ r r r r� � s* �� ����� zFocusedSeq._emitbuildc s � �fdd�| j D �S )Nc s g | ]}|� �� ��qS r rh rE rg r r ro � rp z'FocusedSeq._emitseq.<locals>.<listcomp>rh r r rg r r � s zFocusedSeq._emitseqri r r r r r� ` s 0 r� c @ s e Zd ZdZdd� Zdd� ZdS )�Pickleda� Preserves arbitrary Python objects. Parses using `pickle.load() <https://docs.python.org/3/library/pickle.html#pickle.load>`_ and builds using `pickle.dump() <https://docs.python.org/3/library/pickle.html#pickle.dump>`_ functions, using default Pickle binary protocol. Size is undefined. :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate pickle.load() and pickle.dump() exceptions. Example:: >>> x = [1, 2.3, {}] >>> Pickled.build(x) b'\x80\x03]q\x00(K\x01G@\x02ffffff}q\x01e.' >>> Pickled.parse(_) [1, 2.3, {}] c C s t �|�S r2 )�pickle�loadr� r r r r� s zPickled._parsec C s t �||� |S r2 )r� r r� r r r r� s zPickled._buildNr� r r r r r� � s r� c @ s e Zd ZdZdd� Zdd� ZdS )�Numpya� Preserves numpy arrays (both shape, dtype and values). Parses using `numpy.load() <https://docs.scipy.org/doc/numpy/reference/generated/numpy.load.html#numpy.load>`_ and builds using `numpy.save() <https://docs.scipy.org/doc/numpy/reference/generated/numpy.save.html#numpy.save>`_ functions, using Numpy binary protocol. Size is undefined. :raises ImportError: numpy could not be imported during parsing or building :raises ValueError: could not read enough bytes, or so Can propagate numpy.load() and numpy.save() exceptions. Example:: >>> import numpy >>> a = numpy.asarray([1,2,3]) >>> Numpy.build(a) b"\x93NUMPY\x01\x00F\x00{'descr': '<i8', 'fortran_order': False, 'shape': (3,), } \n\x01\x00\x00\x00\x00\x00\x00\x00\x02\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00\x00" >>> Numpy.parse(_) array([1, 2, 3]) c C s dd l }|�|�S r` )�numpyr� )r r; r� r r� r r r r� # s z Numpy._parsec C s dd l }|�||� |S r` )r� �save)r r� r; r� r r� r r r r� ' s z Numpy._buildNr� r r r r r� s r� c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )� NamedTuplea� Both arrays, structs, and sequences can be mapped to a namedtuple from `collections module <https://docs.python.org/3/library/collections.html#collections.namedtuple>`_. To create a named tuple, you need to provide a name and a sequence of fields, either a string with space-separated names or a list of string names, like the standard namedtuple. Parses into a collections.namedtuple instance, and builds from such instance (although it also builds from lists and dicts). Size is undefined. :param tuplename: string :param tuplefields: string or list of strings :param subcon: Construct instance, either Struct Sequence Array GreedyRange :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises NamedTupleError: subcon is neither Struct Sequence Array GreedyRange Can propagate collections exceptions. Example:: >>> d = NamedTuple("coord", "x y z", Byte[3]) >>> d = NamedTuple("coord", "x y z", Byte >> Byte >> Byte) >>> d = NamedTuple("coord", "x y z", "x"/Byte + "y"/Byte + "z"/Byte) >>> d.parse(b"123") coord(x=49, y=50, z=51) c sD t |ttttf�std��t� �|� || _|| _ t � ||�| _ d S )N�3subcon is neither Struct Sequence Array GreedyRange) rA r& r, r/ rx r% r r � tuplename� tuplefields� collections� namedtuple�factory)r r� r� r� r r r r E s zNamedTuple.__init__c C sN t | jt�r"|d= | jf i |��S t | jtttf�r>| j|� S td|d��d S )NrQ z>subcon is neither Struct Sequence Array GreedyRangeGreedyRanger7 )rA r� r& r� r, r/ rx r% r= r r r r9 M s zNamedTuple._decodec sP t | jt�r&t� fdd�| jjD ��S t | jtttf�r@t� �S t d|d��d S )Nc s" i | ]}|j r|j t� |j ��qS r )r� r� rE �r� r r r� W rp z&NamedTuple._encode.<locals>.<dictcomp>r� r7 ) rA r� r& r� r' r, r/ rx rs r% r= r r� r r: U s zNamedTuple._encodec C sv d|� � }|�d|| j| jf � t| jt�rDd|| j�|�f S t| jtt t f�rjd|| j�|�f S t d��d S )Nz factory_%sz9 %s = collections.namedtuple(%r, %r) z %s(**(%s))z %s(*(%s))r� ) rj rw r� r� rA r� r& r� r, r/ rx r% r| r r r r� \ s � zNamedTuple._emitparsec C s | j �||�S r2 r� r r r r r g s zNamedTuple._emitseqc C s | j �||�S r2 r� r r r r r j s z NamedTuple._emitprimitivetypec C s | j �||�S r2 r� r r r r r m s zNamedTuple._emitfulltype) r r r r r r9 r: r� r r r r r r r r r� - s r� c @ s e Zd ZdZdS )�TimestampAdapterr� Nr r r r r r� q s r� c s ddl � t�t�std��t�tttf�s2td��t�t� jtf�sLtd���dks\�dkr�tdt d� d t d � d t d � d t d � dt d� dt d � �}G � fdd�dt �}||�}n6t�t�rԈ ��dd��G ��fdd�dt �}|��}�fdd�}�fdd�}||_ ||_ |S )a� Datetime, represented as `Arrow <https://pypi.org/project/arrow/>`_ object. Note that accuracy is not guaranteed, because building rounds the value to integer (even when Float subcon is used), due to floating-point errors in general, and because MSDOS scheme has only 5-bit (32 values) seconds field (seconds are rounded to multiple of 2). Unit is a fraction of a second. 1 is second resolution, 10**-3 is milliseconds resolution, 10**-6 is microseconds resolution, etc. Usually its 1 on Unix and MacOSX, 10**-7 on Windows. Epoch is a year (if integer) or a specific day (if Arrow object). Usually its 1970 on Unix, 1904 on MacOSX, 1600 on Windows. MSDOS format doesnt support custom unit or epoch, it uses 2-seconds resolution and 1980 epoch. :param subcon: Construct instance like Int* Float*, or Int32ub with msdos format :param unit: integer or float, or msdos string :param epoch: integer, or Arrow instance, or msdos string :raises ImportError: arrow could not be imported during ctor :raises TimestampError: subcon is not a Construct instance :raises TimestampError: unit or epoch is a wrong type Example:: >>> d = Timestamp(Int64ub, 1., 1970) >>> d.parse(b'\x00\x00\x00\x00ZIz\x00') <Arrow [2018-01-01T00:00:00+00:00]> >>> d = Timestamp(Int32ub, "msdos", "msdos") >>> d.parse(b'H9\x8c"') <Arrow [2016-01-25T17:33:04+00:00]> r NzPsubcon should be Int*, experimentally Float*, or Int32ub when using msdos formatz%unit must be one of: int float stringz&epoch must be one of: int Arrow stringZmsdos�yearr� �monthr� �day� �hour�minute� �secondc s e Zd Z� fdd�Zdd� ZdS )z(Timestamp.<locals>.MsdosTimestampAdapterc s8 � � ddd�j|j|jd |jd |j|j|jd d�S )N� rP rK )Zyears�months�days�hours�minutes�seconds)�Arrow�shiftr� r� r� r� r� r� r= ��arrowr r r9 � s z0Timestamp.<locals>.MsdosTimestampAdapter._decodec S s0 |� � }t|jd |j|j|j|j|jd d�S )Nr� rK )r� r� r� r� r� r� )� timetupler� �tm_year�tm_mon�tm_mday�tm_hour�tm_min�tm_sec)r r� r� r �tr r r r: � s z0Timestamp.<locals>.MsdosTimestampAdapter._encodeN�r r r r9 r: r r� r r �MsdosTimestampAdapter� s r� rP c s( e Zd Z� �fdd�Z� �fdd�ZdS )z(Timestamp.<locals>.EpochTimestampAdapterc s � j |� d�S )N)r� )r� r= ��epoch�unitr r r9 � s z0Timestamp.<locals>.EpochTimestampAdapter._decodec s t |� �� � �S r2 )r\ � total_secondsr= r� r r r: � s z0Timestamp.<locals>.EpochTimestampAdapter._encodeNr� r r� r r �EpochTimestampAdapter� s r� c s � � | |�S r2 rh re rf r r r � s z Timestamp.<locals>._emitfulltypec s � � | |�S r2 rg re rf r r r � s z%Timestamp.<locals>._emitprimitivetype) r� rA r� r& r� �floatr! r� � BitStructr� r� r r ) r� r� r� �str� rn r� r r r )r� r� r� r� r � Timestampu s6 � r� c @ s@ e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dS )�Hexa� Adapter for displaying hexadecimal/hexlified representation of integers/bytes/RawCopy dictionaries. Parsing results in int-alike bytes-alike or dict-alike object, whose only difference from original is pretty-printing. If you look at the result, you will be presented with its `repr` which remains as-is. If you print it, then you will see its `str` whic is a hexlified representation. Building and sizeof defer to subcon. To obtain a hexlified string (like before Hex HexDump changed semantics) use binascii.(un)hexlify on parsed results. Example:: >>> d = Hex(Int32ub) >>> obj = d.parse(b"\x00\x00\x01\x02") >>> obj 258 >>> print(obj) 0x00000102 >>> d = Hex(GreedyBytes) >>> obj = d.parse(b"\x00\x00\x01\x02") >>> obj b'\x00\x00\x01\x02' >>> print(obj) unhexlify('00000102') >>> d = Hex(RawCopy(Int32ub)) >>> obj = d.parse(b"\x00\x00\x01\x02") >>> obj {'data': b'\x00\x00\x01\x02', 'length': 4, 'offset1': 0, 'offset2': 4, 'value': 258} >>> print(obj) unhexlify('00000102') c C sP t |t�r(t�|dd| j�||� �S t |t�r:t|�S t |t�rLt |�S |S )Nz0%sXrK ) rA r� ZHexDisplayedIntegerr! r� r� rB ZHexDisplayedBytesr ZHexDisplayedDictr= r r r r9 � s z Hex._decodec C s |S r2 r r= r r r r: � s z Hex._encodec C s | j �|�S r2 r� r� r r r r� � s zHex._emitparsec C s | j �||�S r2 r� r r r r r � s z Hex._emitseqc C s | j �||�S r2 r� r r r r r � s zHex._emitprimitivetypec C s | j �||�S r2 r� r r r r r � s zHex._emitfulltypeN� r r r r r9 r: r� r r r r r r r r� � s " r� c @ s@ e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dS )�HexDumpa� Adapter for displaying hexlified representation of bytes/RawCopy dictionaries. Parsing results in bytes-alike or dict-alike object, whose only difference from original is pretty-printing. If you look at the result, you will be presented with its `repr` which remains as-is. If you print it, then you will see its `str` whic is a hexlified representation. Building and sizeof defer to subcon. To obtain a hexlified string (like before Hex HexDump changed semantics) use construct.lib.hexdump on parsed results. Example:: >>> d = HexDump(GreedyBytes) >>> obj = d.parse(b"\x00\x00\x01\x02") >>> obj b'\x00\x00\x01\x02' >>> print(obj) hexundump(''' 0000 00 00 01 02 .... ''') >>> d = HexDump(RawCopy(Int32ub)) >>> obj = d.parse(b"\x00\x00\x01\x02") >>> obj {'data': b'\x00\x00\x01\x02', 'length': 4, 'offset1': 0, 'offset2': 4, 'value': 258} >>> print(obj) hexundump(''' 0000 00 00 01 02 .... ''') c C s( t |t�rt|�S t |t�r$t|�S |S r2 )rA rB ZHexDumpDisplayedBytesr ZHexDumpDisplayedDictr= r r r r9 s zHexDump._decodec C s |S r2 r r= r r r r: s zHexDump._encodec C s | j �|�S r2 r� r� r r r r� ! s zHexDump._emitparsec C s | j �||�S r2 r� r r r r r $ s zHexDump._emitseqc C s | j �||�S r2 r� r r r r r ' s zHexDump._emitprimitivetypec C s | j �||�S r2 r� r r r r r * s zHexDump._emitfulltypeNr� r r r r r� � s r� c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )�Uniona% Treats the same data as multiple constructs (similar to C union) so you can look at the data in multiple views. Fields are usually named (so parsed values are inserted into dictionary under same name). Parses subcons in sequence, and reverts the stream back to original position after each subcon. Afterwards, advances the stream by selected subcon. Builds from first subcon that has a matching key in given dict. Size is undefined (because parsefrom is not used for building). This class does context nesting, meaning its members are given access to a new dictionary where the "_" entry points to the outer context. When parsing, each member gets parsed and subcon parse return value is inserted into context under matching key only if the member was named. When building, the matching entry gets inserted into context before subcon gets build, and if subcon build returns a new value (not None) that gets replaced in the context. This class exposes subcons as attributes. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) by accessing the struct attributes, under same name. Also note that compiler does not support this feature. See examples. This class exposes subcons in the context. You can refer to subcons that were inlined (and therefore do not exist as variable in the namespace) within other inlined fields using the context. Note that you need to use a lambda (`this` expression is not supported). Also note that compiler does not support this feature. See examples. .. warning:: If you skip `parsefrom` parameter then stream will be left back at starting offset, not seeked to any common denominator. :param parsefrom: how to leave stream after parsing, can be integer index or string name selecting a subcon, or None (leaves stream at initial offset, the default), or context lambda :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable :raises UnionError: selector does not match any subcon, or dict given to build does not contain any keys matching any subcon :raises IndexError: selector does not match any subcon :raises KeyError: selector does not match any subcon Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Union(0, ... "raw" / Bytes(8), ... "ints" / Int32ub[2], ... "shorts" / Int16ub[4], ... "chars" / Byte[8], ... ) >>> d.parse(b"12345678") Container(raw=b'12345678', ints=[825373492, 892745528], shorts=[12594, 13108, 13622, 14136], chars=[49, 50, 51, 52, 53, 54, 55, 56]) >>> d.build(dict(chars=range(8))) b'\x00\x01\x02\x03\x04\x05\x06\x07' >>> d = Union(None, ... "animal" / Enum(Byte, giraffe=1), ... ) >>> d.animal.giraffe 'giraffe' >>> d = Union(None, ... "chars" / Byte[4], ... "data" / Bytes(lambda this: this._subcons.chars.sizeof()), ... ) >>> d.parse(b"\x01\x02\x03\x04") Container(chars=[1, 2, 3, 4], data=b'\x01\x02\x03\x04') Alternative syntax, but requires Python 3.6 or any PyPy: >>> Union(0, raw=Bytes(8), ints=Int32ub[2], shorts=Int16ub[4], chars=Byte[8]) c s\ t |t�rtd��t� �� || _t|�tdd� |�� D �� | _t dd� | jD ��| _ d S )Nz9parsefrom should be either: None int str context-functionc s s | ]\}}|| V qd S r2 r r� r r r rs m rp z!Union.__init__.<locals>.<genexpr>c s s | ]}|j r|j |fV qd S r2 rD rE r r r rs n rp ) rA r� r' r r � parsefromrs r� r' r� rH )r r� r' rK r r r r h s zUnion.__init__c C s || j v r| j | S t�d S r2 rL r r r r r+ p s zUnion.__getattr__c C s� t � }t ||jd |j|j|j| j||�dd �d� }|j�d|�|_t ||�}i }t | j �D ]b\}}|� |||�} |j r�| ||j < | ||j < t ||�||< |j r�t ||�||j < t||d|� qZt| j|�} | d ur�t||| d|� |S )NrN rO rP r )r� r� r� r� r� rH r> r rP rJ rl r' r� r� rH r� r� ) r r; r� r r� rM Zforwardsr@ r� rS r� r r r r� u s$ , z Union._parsec C s� t ||jd |j|j|j| j||�dd �d� }|j�d|�|_|� |� | j D ]r}|j rf|�|j d �}n|j |v rL||j }nqL|j r�|||j < |� ||||�}|j r�|||j < t |j |i� S td|f |d��d S )NrN rO rP z=cannot build, none of subcons were found in the dictionary %rr7 )r� r� r� r� r� rH r> r rP r� r' r� r� r� r' rU r r r r� � s , z Union._buildc C s t d|d��d S )Nz=Union builds depending on actual object dict, size is unknownr7 r� r� r r r r� � s z Union._sizeofc C sj t | j�rtd��d|�� }d|f }t| jtd ��rDd}d}d}t| jt�r�| j}| j| d}| j| �� | jd �� k}t| jt �r�dd� t | j�D �| j }d}| j| �� | jd �� k}t | j�D ]`\}}|d |j r�d |j nd |� |�f 7 }||k�r|�s|d 7 }|t | j�d k r�|d7 }q�|�s@|d7 }|�sN|d7 }|d7 }|�|� d|f S )Nz-Union does not compile non-constant parsefromzparse_union_%saP def %s(io, this): this = Container(_ = this, _params = this['_params'], _root = None, _parsing = True, _building = False, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) fallback = io.tell() ���FTc S s i | ]\}}|j r|j |�qS r rD �rm r@ r� r r r r� � rp z$Union._emitparse.<locals>.<dictcomp>z" %s%s z this[%r] = r z5 forward = io.tell() rP z3 io.seek(fallback) z/ io.seek(fallback) z. io.seek(forward) zf del this['_'] del this['_index'] return this z %s(io, this))r� r� r� rj rA r r\ r' r� r] rl r� r� r: rw ) r r� r} rx �indexZ skipfallbackZ skipforwardr@ r� r r r r� � sD � � zUnion._emitparsec C s� d|� � � �}d|� d�}| jD ]�}|d|jr2dnt|j�� d�� d|jr\dt|j�� d �nd t|j�� d �� d |jr�d t|j�� d�nd� d |jr�dt|j�� d�nd� |�|�� d dt|j�� d�� d� 7 }q |d7 }|�|� |� d�S )NZ build_union_rY a\ (obj, io, this): this = Container(_ = this, _params = this['_params'], _root = None, _parsing = False, _building = True, _sizing = False, _subcons = None, _io = io, _index = this.get('_index', None)) this['_root'] = this['_'].get('_root', this) this.update(obj) objdict = obj z if �Truez in objdictz: r` ra rb rC rZ rc rd r zbuildret = this[r[ zreturn Container({ z :buildret })r\ zh raise UnionError('cannot build, none of subcons were found in the dictionary') re rf r_ r r r r� � s* � �(����� zUnion._emitbuild) r r r r r r+ r� r� r� r� r� r r r r r r� 1 s 6 4r� c s0 e Zd ZdZ� fdd�Zdd� Zdd� Z� ZS )�Selectu? Selects the first matching subconstruct. Parses and builds by literally trying each subcon in sequence until one of them parses or builds without exception. Stream gets reverted back to original position after each failed attempt, but not if parsing succeeds. Size is not defined. :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable :raises SelectError: neither subcon succeded when parsing or building Example:: >>> d = Select(Int32ub, CString("utf8")) >>> d.build(1) b'\x00\x00\x00\x01' >>> d.build(u"Афон") b'\xd0\x90\xd1\x84\xd0\xbe\xd0\xbd\x00' Alternative syntax, but requires Python 3.6 or any PyPy: >>> Select(num=Int32ub, text=CString("utf8")) c sD t � �� t|�tdd� |�� D �� | _tdd� | jD ��| _d S )Nc s s | ]\}}|| V qd S r2 r r� r r r rs rp z"Select.__init__.<locals>.<genexpr>c s s | ] }|j V qd S r2 rF rE r r r rs rp )r r rs r� r' �anyr� rJ r r r r s zSelect.__init__c C st | j D ]\}t||�}z|�|||�}W n2 ty: � Y q tyX t||d|� Y q0 | S qtd|d��d S )Nr zno subconstruct matchedr7 )r' rJ r� r$ r9 rH r( )r r; r� r r� rM r� r r r r� s z Select._parsec C sx | j D ]Z}z|j|fi |��}W n$ ty4 � Y q tyD Y q0 t||t|�|� | S qtd|f |d��d S )Nzno subconstruct matched: %sr7 )r' r� r$ r9 rD r: r( )r r� r; r� r r� r= r r r r� s z Select._build�r r r r r r� r� r r r r r r� � s r� c C s t | t�S )a� Makes an optional field. Parsing attempts to parse subcon. If sub-parsing fails, returns None and reports success. Building attempts to build subcon. If sub-building fails, writes nothing and reports success. Size is undefined, because whether bytes would be consumed or produced depends on actual data and actual context. :param subcon: Construct instance Example:: Optional <--> Select(subcon, Pass) >>> d = Optional(Int64ul) >>> d.parse(b"12345678") 4050765991979987505 >>> d.parse(b"") None >>> d.build(1) b'\x01\x00\x00\x00\x00\x00\x00\x00' >>> d.build(None) b'' )r� �Passrf r r r �Optional' s r� c s$ t � �t�}� �fdd�}||_|S )aq If-then conditional construct. Parsing evaluates condition, if True then subcon is parsed, otherwise just returns None. Building also evaluates condition, if True then subcon gets build from, otherwise does nothing. Size is either same as subcon or 0, depending how condfunc evaluates. :param condfunc: bool or context lambda (or a truthy value) :param subcon: Construct instance, used if condition indicates True :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: If <--> IfThenElse(condfunc, subcon, Pass) >>> d = If(this.x > 0, Byte) >>> d.build(255, x=1) b'\xff' >>> d.build(255, x=0) b'' c s t ��| |�t� ��dd�d�S )N�this.r )r �if_)r r r5 r� re ��condfuncr� r r r Y s zIf.<locals>._emitfulltype)� IfThenElser� r )r� r� rn r r r� r �If@ s r� c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )r� aR If-then-else conditional construct, similar to ternary operator. Parsing and building evaluates condition, and defers to either subcon depending on the value. Size is computed the same way. :param condfunc: bool or context lambda (or a truthy value) :param thensubcon: Construct instance, used if condition indicates True :param elsesubcon: Construct instance, used if condition indicates False :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = IfThenElse(this.x > 0, VarInt, Byte) >>> d.build(255, dict(x=1)) b'\xff\x01' >>> d.build(255, dict(x=0)) b'\xff' c s. t � �� || _|| _|| _|jo&|j| _d S r2 )r r r� � thensubcon� elsesubconr� )r r� r� r� r r r r w s zIfThenElse.__init__c C s* t | j|�}|r| jn| j}|�|||�S r2 )r� r� r� r� r� )r r; r� r r� r� r r r r� ~ s zIfThenElse._parsec C s, t | j|�}|r| jn| j}|�||||�S r2 )r� r� r� r� r� )r r� r; r� r r� r� r r r r� � s zIfThenElse._buildc C s( t | j|�}|r| jn| j}|�||�S r2 )r� r� r� r� r� )r r� r r� r� r r r r� � s zIfThenElse._sizeofc C s d| j �|�| j| j�|�f S )Nz((%s) if (%s) else (%s)))r� r� r� r� r� r r r r� � s zIfThenElse._emitparsec C s. d| j �|�� dt| j�� d| j�|�� d�S )Nz((z) if (z) else (r1 )r� r� r5 r� r� r� r r r r� � s zIfThenElse._emitbuildc C sN t d| j�||�t| j��dd�d�t d| j�||�t| j ��dd�d�gS )NZ thenvaluer� r )r� r r� r� )r r� r r5 r� r� r� r r r r r � s $&�zIfThenElse._emitseq) r r r r r r� r� r� r� r� r r r r r r r� ` s r� c sJ e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z � Z S )�Switcha+ A conditional branch. Parsing and building evaluate keyfunc and select a subcon based on the value and dictionary entries. Dictionary (cases) maps values into subcons. If no case matches then `default` is used (that is Pass by default). Note that `default` is a Construct instance, not a dictionary key. Size is evaluated in same way as parsing and building, by evaluating keyfunc and selecting a field accordingly. :param keyfunc: context lambda or constant, that matches some key in cases :param cases: dict mapping keys to Construct instances :param default: optional, Construct instance, used when keyfunc is not found in cases, Pass is default value for this parameter, Error is a possible value for this parameter :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Switch(this.n, { 1:Int8ub, 2:Int16ub, 4:Int32ub }) >>> d.build(5, n=1) b'\x05' >>> d.build(5, n=4) b'\x00\x00\x00\x05' >>> d = Switch(this.n, {}, default=Byte) >>> d.parse(b"\x01", n=255) 1 >>> d.build(1, n=255) b"\x01" Nc sR |d u r t }t� �� || _|| _|| _t|�� �|g }tdd� |D ��| _ d S )Nc s s | ] }|j V qd S r2 rF rE r r r rs � rp z"Switch.__init__.<locals>.<genexpr>) r� r r �keyfunc�cases�defaultrs �valuesrI r� )r r� r� r� Zallcasesr r r r � s zSwitch.__init__c C s* t | j|�}| j�|| j�}|�|||�S r2 )r� r� r� r> r� r� )r r; r� r r� r� r r r r� � s z Switch._parsec C s, t | j|�}| j�|| j�}|�||||�S r2 )r� r� r� r> r� r� )r r� r; r� r r� r� r r r r� � s z Switch._buildc C sR z*t | j|�}| j�|| j�}|�||�W S ttfyL td|d��Y n0 d S rN ) r� r� r� r> r� r� rP rQ r )r r� r r� r� r r r r� � s zSwitch._sizeofc C s� d|� � � �}|�|� d�� | j�� D ],\}}|�|� dt|�� d|�|�� �� q(d|� � � �}|�|� d| j�|�� �� |� dt| j�� d|� d �S ) N� switch_cases_� = {}rB z] = lambda io,this: �switch_defaultcase_z = lambda io,this: �.get(r� z )(io, this))rj rw r� r� r5 r� r� r� �r r� r} �keyr� Z defaultfnamer r r r� � s & zSwitch._emitparsec C s� d|� � � �}|�|� d�� | j�� D ],\}}|�|� dt|�� d|�|�� �� q(d|� � � �}|�|� d| j�|�� �� |� dt| j�� d|� d �S ) Nr� r� rB z] = lambda obj,io,this: r� z = lambda obj,io,this: r� r� z)(obj, io, this))rj rw r� r� r5 r� r� r� r� r r r r� � s & zSwitch._emitbuild)Nr� r r r r r� � s r� c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�StopIfa� Checks for a condition, and stops certain classes (:class:`~construct.core.Struct` :class:`~construct.core.Sequence` :class:`~construct.core.GreedyRange`) from parsing or building further. Parsing and building check the condition, and raise StopFieldError if indicated. Size is undefined. :param condfunc: bool or context lambda (or truthy value) :raises StopFieldError: used internally Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> Struct('x'/Byte, StopIf(this.x == 0), 'y'/Byte) >>> Sequence('x'/Byte, StopIf(this.x == 0), 'y'/Byte) >>> GreedyRange(FocusedSeq(0, 'x'/Byte, StopIf(this.x == 0))) c s t � �� || _d| _d S r8 )r r r� r� )r r� r r r r � s zStopIf.__init__c C s t | j|�}|rt|d��d S rE �r� r� r* )r r; r� r r� r r r r� � s z StopIf._parsec C s t | j|�}|rt|d��d S rE r� )r r� r; r� r r� r r r r� s z StopIf._buildc C s t d|d��d S )NzxStopIf cannot determine size because it depends on actual context which then depends on actual data and outer constructsr7 r� r� r r r r� s zStopIf._sizeofc C s |� d� dt| j�� d�S )Nzy def parse_stopif(condition): if condition: raise StopFieldError z parse_stopif(rS �rw r5 r� r� r r r r� s zStopIf._emitparsec C s |� d� dt| j�� d�S )Nzy def build_stopif(condition): if condition: raise StopFieldError z build_stopif(rS r� r� r r r r� s zStopIf._emitbuildr� r r r r r� � s r� r c s6 t � t|d�}� fdd�}� fdd�}||_||_|S )ap Appends null bytes. Parsing consumes specified amount of bytes and discards it. Building writes specified pattern byte multiplied into specified length. Size is same as specified. :param length: integer or context lambda, length of the padding :param pattern: b-character, padding pattern, default is \\x00 :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises PaddingError: length was negative :raises PaddingError: pattern was not bytes (b-character) Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Padding(4) or Padded(4, Pass) >>> d.build(None) b'\x00\x00\x00\x00' >>> d.parse(b"****") None >>> d.sizeof() 4 )�patternc s |st �d� f S r� r� re rT r r r : s z#Padding.<locals>._emitprimitivetypec s |rt �t� d�S rV )r� r re rT r r r > s z Padding.<locals>._emitfulltype)�Paddedr� r r )r< r� rn r r r rT r �Padding s r� c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )r� a� Appends additional null bytes to achieve a length. Parsing first parses the subcon, then uses stream.tell() to measure how many bytes were read and consumes additional bytes accordingly. Building first builds the subcon, then uses stream.tell() to measure how many bytes were written and produces additional bytes accordingly. Size is same as `length`, but negative amount results in error. Note that subcon can actually be variable size, it is the eventual amount of bytes that is read or written during parsing or building that determines actual padding. :param length: integer or context lambda, length of the padding :param subcon: Construct instance :param pattern: optional, b-character, padding pattern, default is \\x00 :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises PaddingError: length is negative :raises PaddingError: subcon read or written more than the length (would cause negative pad) :raises PaddingError: pattern is not bytes of length 1 Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Padded(4, Byte) >>> d.build(255) b'\xff\x00\x00\x00' >>> d.parse(_) 255 >>> d.sizeof() 4 >>> d = Padded(4, VarInt) >>> d.build(1) b'\x01\x00\x00\x00' >>> d.build(70000) b'\xf0\xa2\x04\x00' r c s: t |t�rt|�dkr td��t� �|� || _|| _d S )NrP z(pattern expected to be bytes of length 1)rA rB r: r+ r r r< r� )r r< r� r� r r r r i s zPadded.__init__c C s� t | j|�}|dk r td|d��t||�}| j�|||�}t||�}||| }|dk rptd|| |f |d��t|||� |S )Nr �length cannot be negativer7 z.subcon parsed %d bytes but was allowed only %d)r� r< r+ rJ r� r� r> ) r r; r� r r< � position1r� � position2r r r r r� p s z Padded._parsec C s� t | j|�}|dk r td|d��t||�}| j�||||�}t||�}||| } | dk rrtd|| |f |d��t|| j| | |� |S �Nr r� r7 z-subcon build %d bytes but was allowed only %d)r� r< r+ rJ r� r� rD r� ) r r� r; r� r r< r� r< r r r r r r� } s z Padded._buildc C sN z&t | j|�}|dk r"td|d��|W S ttfyH td|d��Y n0 d S )Nr r� r7 rO )r� r< r+ rP rQ r �r r� r r< r r r r� � s zPadded._sizeofc C s( d| j �|�� d| j� d| j �� � d�S )N�(z , io.read((�)-(�) ))[0])r� r� r< r� r� r r r r� � s zPadded._emitparsec C s4 d| j �|�� dt| j�� d| j� d| j �� � d� S )Nr � , io.write(z*((r z)) ))[0])r� r� r5 r� r< r� r� r r r r� � s zPadded._emitbuildc C s t | j| j�||�d�S )N)rX r )r r< r� r r r r r r � s zPadded._emitfulltype)r rY r r r r r� G s ! r� c sJ e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z � Z S )�Aligneda� Appends additional null bytes to achieve a length that is shortest multiple of a modulus. Note that subcon can actually be variable size, it is the eventual amount of bytes that is read or written during parsing or building that determines actual padding. Parsing first parses subcon, then consumes an amount of bytes to sum up to specified length, and discards it. Building first builds subcon, then writes specified pattern byte to sum up to specified length. Size is subcon size plus modulo remainder, unless SizeofError was raised. :param modulus: integer or context lambda, modulus to final length :param subcon: Construct instance :param pattern: optional, b-character, padding pattern, default is \\x00 :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises PaddingError: modulus was less than 2 :raises PaddingError: pattern was not bytes (b-character) Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Aligned(4, Int16ub) >>> d.parse(b'\x00\x01\x00\x00') 1 >>> d.sizeof() 4 r c s: t |t�rt|�dkr td��t� �|� || _|| _d S )NrP z&pattern expected to be bytes character)rA rB r: r+ r r �modulusr� )r r r� r� r r r r � s zAligned.__init__c C sb t | j|�}|dk r td|d��t||�}| j�|||�}t||�}|| | }t|||� |S �NrK � expected modulo 2 or greaterr7 )r� r r+ rJ r� r� r> ) r r; r� r r r� r� r r r r r r� � s zAligned._parsec C sl t | j|�}|dk r td|d��t||�}| j�||||�}t||�}|| | } t|| j| | |� |S r )r� r r+ rJ r� r� rD r� ) r r� r; r� r r r� r< r r r r r r� � s zAligned._buildc C sf z>t | j|�}|dk r"td|d��| j�||�}|| | W S ttfy` td|d��Y n0 d S )NrK r r7 rO )r� r r+ r� r� rP rQ r )r r� r r Z subconlenr r r r� � s zAligned._sizeofc C s( d| j �|�� d| j �� � d| j� d�S )Nr z , io.read(-(�) % (r )r� r� r� r r� r r r r� � s zAligned._emitparsec C s4 d| j �|�� dt| j�� d| j �� � d| j� d� S )Nr r z*(-(r z))) )[0])r� r� r5 r� r� r r� r r r r� � s zAligned._emitbuild)r r� r r r r r � s r c s4 t |�t dd� |�� D �� }t� fdd�|D �� S )a� Makes a structure where each field is aligned to the same modulus (it is a struct of aligned fields, NOT an aligned struct). See :class:`~construct.core.Aligned` and :class:`~construct.core.Struct` for semantics and raisable exceptions. :param modulus: integer or context lambda, passed to each member :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) Example:: >>> d = AlignedStruct(4, "a"/Int8ub, "b"/Int16ub) >>> d.build(dict(a=0xFF,b=0xFFFF)) b'\xff\x00\x00\x00\xff\xff\x00\x00' c s s | ]\}}|| V qd S r2 r r� r r r rs � rp z AlignedStruct.<locals>.<genexpr>c s g | ]}|j t� |� �qS r )r� r rE �r r r ro � rp z!AlignedStruct.<locals>.<listcomp>)rs r� r& )r r' rK r r r � AlignedStruct� s r c O s t t| i |���S )a� Makes a structure inside a Bitwise. See :class:`~construct.core.Bitwise` and :class:`~construct.core.Struct` for semantics and raisable exceptions. :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) Example:: BitStruct <--> Bitwise(Struct(...)) >>> d = BitStruct( ... "a" / Flag, ... "b" / Nibble, ... "c" / BitsInteger(10), ... "d" / Padding(1), ... ) >>> d.parse(b"\xbe\xef") Container(a=True, b=7, c=887, d=None) >>> d.sizeof() 2 )ro r& )r' rK r r r r� � s r� c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )�PointeraC Jumps in the stream forth and back for one field. Parsing and building seeks the stream to new location, processes subcon, and seeks back to original location. Size is defined as 0 but that does not mean no bytes are written into the stream. Offset can be positive, indicating a position from stream beginning forward, or negative, indicating a position from EOF backwards. :param offset: integer or context lambda, positive or negative :param subcon: Construct instance :param stream: None to use original stream (default), or context lambda to provide a different stream :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Pointer(8, Bytes(1)) >>> d.parse(b"abcdefghijkl") b'i' >>> d.build(b"Z") b'\x00\x00\x00\x00\x00\x00\x00\x00Z' Nc s t � �|� || _|| _d S r2 )r r rF r; )r rF r� r; r r r r 2 s zPointer.__init__c C sb t | j|�}t | j|�p|}t||�}t|||dk r8dnd|� | j�|||�}t||d|� |S �Nr rK )r� rF r; rJ rH r� r� )r r; r� r rF rM r� r r r r� 7 s zPointer._parsec C sd t | j|�}t | j|�p|}t||�}t|||dk r8dnd|� | j�||||�}t||d|� |S r )r� rF r; rJ rH r� r� )r r� r; r� r rF rM r< r r r r� @ s zPointer._buildc C s dS r` r r� r r r r� I s zPointer._sizeofc C s& |� d� d| j� d| j�|�� d�S )Nz� def parse_pointer(io, offset, func): fallback = io.tell() io.seek(offset, 2 if offset < 0 else 0) obj = func() io.seek(fallback) return obj zparse_pointer(io, � , lambda: rS )rw rF r� r� r� r r r r� L s zPointer._emitparsec C s& |� d� d| j� d| j�|�� d�S )Nz� def build_pointer(obj, io, offset, func): fallback = io.tell() io.seek(offset, 2 if offset < 0 else 0) ret = func() io.seek(fallback) return ret zbuild_pointer(obj, io, r rS )rw rF r� r� r� r r r r� W s zPointer._emitbuildc C sL t | j�r| j�� n| j}d|�� }tf d|i| j�||���|j|< |S )Nz instance_%s�pos)r� rF Z __getfield__rj r r� r r| )r r r rF r� r r r r b s "zPointer._emitprimitivetype)Nr� r r r r r s r c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�Peeka� Peeks at the stream. Parsing sub-parses (and returns None if failed), then reverts stream to original position. Building does nothing (its NOT deferred). Size is defined as 0 because there is no building. This class is used in :class:`~construct.core.Union` class to parse each member. :param subcon: Construct instance :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable Example:: >>> d = Sequence(Peek(Int8ub), Peek(Int16ub)) >>> d.parse(b"\x01\x02") [1, 258] >>> d.sizeof() 0 c s t � �|� d| _d S r8 r� r4 r r r r s z Peek.__init__c C sz t ||�}zZz"| j�|||�W W t||d|� S tyB � Y n tyR Y n0 W t||d|� nt||d|� 0 d S r` )rJ r� r� rH r$ r )r r; r� r rM r r r r� � s � z Peek._parsec C s |S r2 r r� r r r r� � s z Peek._buildc C s dS r` r r� r r r r� � s z Peek._sizeofc C s |� d� d| j�|�f S )NaJ def parse_peek(io, func): fallback = io.tell() try: return func() except ExplicitError: raise except ConstructError: pass finally: io.seek(fallback) zparse_peek(io, lambda: %s))rw r� r� r� r r r r� � s zPeek._emitparsec C s dS )Nr� r r� r r r r� � s zPeek._emitbuildr� r r r r r i s r c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) � OffsettedEnda� Parses all bytes in the stream till `EOF plus a negative endoffset` is reached. This is useful when GreedyBytes (or any other greedy construct) is followed by a fixed-size footer. Parsing determines the length of the stream and reads all bytes till EOF plus `endoffset` is reached, then defers to subcon using new BytesIO with said bytes. Building defers to subcon as-is. Size is undefined. :param endoffset: integer or context lambda, only negative offsets or zero are allowed :param subcon: Construct instance :raises StreamError: could not read enough bytes :raises StreamError: reads behind the stream (if endoffset is positive) Example:: >>> d = Struct( ... "header" / Bytes(2), ... "data" / OffsettedEnd(-2, GreedyBytes), ... "footer" / Bytes(2), ... ) >>> d.parse(b"\x01\x02\x03\x04\x05\x06\x07") Container(header=b'\x01\x02', data=b'\x03\x04\x05', footer=b'\x06\x07') c s t � �|� || _d S r2 )r r � endoffset)r r r� r r r r � s zOffsettedEnd.__init__c C sf t | j|�}t||�}t|dd|� t||�}t||d|� || | }t�|||�}| j�|||�S r )r� r rJ rH rR rT r� r� ) r r; r� r r Zcurpos�endposr< � substreamr r r r� � s zOffsettedEnd._parsec C s | j �||||�S r2 r6 r� r r r r� � s zOffsettedEnd._buildc C s t |d��d S rE r� r� r r r r� � s zOffsettedEnd._sizeofr� r r r r r � s r c sJ e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z � Z S )�SeekaZ Seeks the stream. Parsing and building seek the stream to given location (and whence), and return stream.seek() return value. Size is not defined. .. seealso:: Analog :class:`~construct.core.Pointer` wrapper that has same side effect but also processes a subcon, and also seeks back. :param at: integer or context lambda, where to jump to :param whence: optional, integer or context lambda, is the offset from beginning (0) or from current position (1) or from EOF (2), default is 0 :raises StreamError: stream is not seekable Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = (Seek(5) >> Byte) >>> d.parse(b"01234x") [5, 120] >>> d = (Bytes(10) >> Seek(5) >> Byte) >>> d.build([b"0123456789", None, 255]) b'01234\xff6789' r c s t � �� || _|| _d| _d S r8 )r r �atrG r� )r r rG r r r r � s z Seek.__init__c C s& t | j|�}t | j|�}t||||�S r2 �r� r rG rH )r r; r� r r rG r r r r� � s z Seek._parsec C s& t | j|�}t | j|�}t||||�S r2 r )r r� r; r� r r rG r r r r� � s z Seek._buildc C s t d|d��d S )Nz2Seek only moves the stream, size is not meaningfulr7 r� r� r r r r� � s z Seek._sizeofc C s d| j � d| j� d�S �Nzio.seek(r� rS �r rG r� r r r r� s zSeek._emitparsec C s d| j � d| j� d�S r r r� r r r r� s zSeek._emitbuild)r r� r r r r r � s r c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )�Tella1 Tells the stream. Parsing and building return current stream offset using using stream.tell(). Size is defined as 0 because parsing and building does not consume or add into the stream. Tell is useful for adjusting relative offsets to absolute positions, or to measure sizes of Constructs. To get an absolute pointer, use a Tell plus a relative offset. To get a size, place two Tells and measure their difference using a Compute field. However, its recommended to use :class:`~construct.core.RawCopy` instead of manually extracting two positions and computing difference. :raises StreamError: stream is not tellable Example:: >>> d = Struct("num"/VarInt, "offset"/Tell) >>> d.parse(b"X") Container(num=88, offset=1) >>> d.build(dict(num=88)) b'X' c s t � �� d| _d S r8 r� rX r r r r s z Tell.__init__c C s t ||�S r2 �rJ r� r r r r� ! s z Tell._parsec C s t ||�S r2 r r� r r r r� $ s z Tell._buildc C s dS r` r r� r r r r� ' s z Tell._sizeofc C s dS �Nz io.tell()r r� r r r r� * s zTell._emitparsec C s dS r r r� r r r r� - s zTell._emitbuildr� r r r r r s r c sP e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z � Z S )r� a No-op construct, useful as default cases for Switch and Enum. Parsing returns None. Building does nothing. Size is 0 by definition. Example:: >>> Pass.parse(b"") None >>> Pass.build(None) b'' >>> Pass.sizeof() 0 c s t � �� d| _d S r8 r� rX r r r r B s z Pass.__init__c C s d S r2 r r� r r r r� F s z Pass._parsec C s |S r2 r r� r r r r� I s z Pass._buildc C s dS r` r r� r r r r� L s z Pass._sizeofc C s dS �Nr� r r� r r r r� O s zPass._emitparsec C s dS r r r� r r r r� R s zPass._emitbuildc C s t dd�S )Nr rW r] r r r r r U s zPass._emitfulltyperY r r r r r� 1 s r� c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) � Terminateda5 Asserts end of stream (EOF). You can use it to ensure no more unparsed data follows in the stream. Parsing checks if stream reached EOF, and raises TerminatedError if not. Building does nothing. Size is defined as 0 because parsing and building does not consume or add into the stream, as far as other constructs see it. :raises TerminatedError: stream not at EOF when parsing Example:: >>> Terminated.parse(b"") None >>> Terminated.parse(b"remaining") construct.core.TerminatedError: expected end of stream c s t � �� d| _d S r8 r� rX r r r r j s zTerminated.__init__c C s |� d�rtd|d��d S )NrP zexpected end of streamr7 )r8 r, r� r r r r� n s zTerminated._parsec C s |S r2 r r� r r r r� r s zTerminated._buildc C s t |d��d S rE r� r� r r r r� u s zTerminated._sizeofr� r r r r r Y s r c @ s e Zd ZdZdd� Zdd� ZdS )�RawCopya� Used to obtain byte representation of a field (aside of object value). Returns a dict containing both parsed subcon value, the raw bytes that were consumed by subcon, starting and ending offset in the stream, and amount in bytes. Builds either from raw bytes representation or a value used by subcon. Size is same as subcon. Object is a dictionary with either "data" or "value" keys, or both. When building, if both the "value" and "data" keys are present, then the "data" key is used and the "value" key is ignored. This is undesirable in the case that you parse some data for the purpose of modifying it and writing it back; in this case, delete the "data" key when modifying the "value" key to correctly rebuild the former. :param subcon: Construct instance :raises StreamError: stream is not seekable and tellable :raises RawCopyError: building and neither data or value was given :raises StringError: building from non-bytes value, perhaps unicode Example:: >>> d = RawCopy(Byte) >>> d.parse(b"\xff") Container(data=b'\xff', value=255, offset1=0, offset2=1, length=1) >>> d.build(dict(data=b"\xff")) '\xff' >>> d.build(dict(value=255)) '\xff' c C sX t ||�}| j�|||�}t ||�}t||d|� t||| |�}t|||||| d�S )Nr �r= r� �offset1�offset2r< )rJ r� r� rH r> r� )r r; r� r r# r� r$ r= r r r r� � s zRawCopy._parsec C s� |d u r| j jrtd d�}d|v rf|d }t||�}t||t|�|� t||�}t|||||| d�S d|v r�|d }t||�}| j �||||�} | d u r�|n| }t||�}t||d|� t ||| |�}t||||||| d�S t d|d��d S ) N)r� r= )r= r# r$ r< r� r r" z:RawCopy cannot build, both data and value keys are missingr7 ) r� r� r rJ rD r: r� r� rH r> r- ) r r� r; r� r r= r# r$ r� r< r r r r� � s$ zRawCopy._buildNr� r r r r r! | s r! c C s | � � }t| t|t|�S )a� Swaps the byte order within boundaries of given subcon. Requires a fixed sized subcon. :param subcon: Construct instance, subcon on top of byte swapped bytes :raises SizeofError: ctor or compiler could not compute subcon size See :class:`~construct.core.Transformed` and :class:`~construct.core.Restreamed` for raisable exceptions. Example:: Int24ul <--> ByteSwapped(Int24ub) <--> BytesInteger(3, swapped=True) <--> ByteSwapped(BytesInteger(3)) )r� ri r� �r� rX r r r � ByteSwapped� s r& c C sH z| � � }t| t|t|�W S tyB t| tdtddd� � Y S 0 dS )aC Swaps the bit order within each byte within boundaries of given subcon. Does NOT require a fixed sized subcon. :param subcon: Construct instance, subcon on top of bit swapped bytes :raises SizeofError: compiler could not compute subcon size See :class:`~construct.core.Transformed` and :class:`~construct.core.Restreamed` for raisable exceptions. Example:: >>> d = Bitwise(Bytes(8)) >>> d.parse(b"\x01") '\x00\x00\x00\x00\x00\x00\x00\x01' >>>> BitsSwapped(d).parse(b"\x01") '\x01\x00\x00\x00\x00\x00\x00\x00' rP c S s | S r2 r r` r r r r� � rp z BitsSwapped.<locals>.<lambda>N)r� ri Zswapbitsinbytesr rl r% r r r � BitsSwapped� s r' c sR e Zd ZdZd� fdd� Zdd� Zdd� Zd d � Zd d � Zd d� Z dd� Z � Z S )r a� Prefixes a field with byte count. Parses the length field. Then reads that amount of bytes, and parses subcon using only those bytes. Constructs that consume entire remaining stream are constrained to consuming only the specified amount of bytes (a substream). When building, data gets prefixed by its length. Optionally, length field can include its own size. Size is the sum of both fields sizes, unless either raises SizeofError. Analog to :class:`~construct.core.PrefixedArray` which prefixes with an element count, instead of byte count. Semantics is similar but implementation is different. :class:`~construct.core.VarInt` is recommended for new protocols, as it is more compact and never overflows. :param lengthfield: Construct instance, field used for storing the length :param subcon: Construct instance, subcon used for storing the value :param includelength: optional, bool, whether length field should include its own size, default is False :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes Example:: >>> d = Prefixed(VarInt, GreedyRange(Int32ul)) >>> d.parse(b"\x08abcdefgh") [1684234849, 1751606885] >>> d = PrefixedArray(VarInt, Int32ul) >>> d.parse(b"\x02abcdefgh") [1684234849, 1751606885] Fc s t � �|� || _|| _d S r2 )r r r � includelength)r r r� r( r r r r � s zPrefixed.__init__c C sF | j �|||�}| jr(|| j �||�8 }t�|||�}| j�|||�S r2 )r r� r( r� rR rT r� �r r; r� r r< r r r r r� s zPrefixed._parsec C sj t �� }| j�||||�}|�� }t|�}| jrB|| j�||�7 }| j�||||� t ||t|�|� |S r2 ) rY r� r� r� r� r: r( r r� rD ) r r� r; r� r rD r< r= r< r r r r� s zPrefixed._buildc C s | j �||�| j�||� S r2 )r r� r� r� r r r r� s zPrefixed._sizeofc C sH t ||�}| j�|||�}| jr2|| j�||�8 }t ||�}|| | S r2 )rJ r r� r( r� )r r; r� r r� r< r r r r r� s zPrefixed._actualsizec C s< | j r| j�� nd}d| j�|�� d|� d| j�|�� d�S )Nr zrestream(io.read((r z)), lambda io: (r1 )r( r r� r� r� )r r� �subr r r r� s zPrefixed._emitparsec C s. t d| j�||�d�t dd| j�||�d�gS )Nr r r= )r� rX r )r r r r� r r r r r " s �zPrefixed._emitseq)F) r r r r r r� r� r� r� r� r r r r r r r � s r c sz t ddt� ttj�� d�tj �}� �fdd�}||_� �fdd�}||_� �fdd�}||_� �fd d �}||_ |S ) a} Prefixes an array with item count (as opposed to prefixed by byte count, see :class:`~construct.core.Prefixed`). :class:`~construct.core.VarInt` is recommended for new protocols, as it is more compact and never overflows. :param countfield: Construct instance, field used for storing the element count :param subcon: Construct instance, subcon used for storing each element :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises RangeError: consumed or produced too little elements Example:: >>> d = Prefixed(VarInt, GreedyRange(Int32ul)) >>> d.parse(b"\x08abcdefgh") [1684234849, 1751606885] >>> d = PrefixedArray(VarInt, Int32ul) >>> d.parse(b"\x02abcdefgh") [1684234849, 1751606885] r� r0 c s d�� | �� � | �f S )Nz&ListContainer((%s) for i in range(%s)))r� r �� countfieldr� r r r� D s z!PrefixedArray.<locals>._emitparsec s d� � | �� d�� | �� d�S )Nz (reuse(len(obj), lambda obj: z), list(z for obj in obj), obj)[2])r� r r+ r r r� H s z!PrefixedArray.<locals>._emitbuildc s: t ||�}� �|||�}t ||�}|| |��||� S r2 )rJ r� r� )r r; r� r r� r0 r r+ r r r� L s z"PrefixedArray.<locals>._actualsizec s, t d� �| |�d�t d��| |�ddd�gS )Nr, r r= ru )r� r rv rw r re r+ r r r S s �z PrefixedArray.<locals>._emitseq) r� r� Zlen_�thisr� r0 r� r� r� r )r, r� rn r� r� r� r r r+ r � PrefixedArray) s �r. c sH e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Zd d � Z � Z S )r a: Restricts parsing to specified amount of bytes. Parsing reads `length` bytes, then defers to subcon using new BytesIO with said bytes. Building builds the subcon using new BytesIO, then writes said data and additional null bytes accordingly. Size is same as `length`, although negative amount raises an error. :param length: integer or context lambda, total amount of bytes (both data and padding) :param subcon: Construct instance :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises PaddingError: length is negative :raises PaddingError: subcon written more bytes than entire length (negative padding) Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = FixedSized(10, Byte) >>> d.parse(b'\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00') 255 >>> d.build(255) b'\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00' >>> d.sizeof() 10 c s t � �|� || _d S r2 rK )r r< r� r r r r w s zFixedSized.__init__c C s> t | j|�}|dk r td|d��t�|||�}| j�|||�S �Nr r� r7 )r� r< r+ rR rT r� r� r) r r r r� { s zFixedSized._parsec C s� t | j|�}|dk r td|d��t�� }| j�||||�}|�� }|t|� } | dk rntdt|�|f |d��t ||t|�|� t |t | �| |� |S r ) r� r< r+ rY r� r� r� r� r: rD r^ ) r r� r; r� r r< rD r< r= r r r r r� � s zFixedSized._buildc C s$ t | j|�}|dk r td|d��|S r/ )r� r< r+ r r r r r� � s zFixedSized._sizeofc C s d| j � d| j�|�� d�S )Nzrestream(io.read(z), lambda io: (r1 )r< r� r� r� r r r r� � s zFixedSized._emitparsec C s* t f dt| j��dd�i| j�||���S )NrX r� r )r r5 r< r� r� r r r r r r � s zFixedSized._emitfulltype) r r r r r r� r� r� r� r r r r r r r ] s r c sB e Zd ZdZd� fdd� Zdd� Zd d � Zd d � Zd d� Z� Z S )r a Restricts parsing to bytes preceding a null byte. Parsing reads one byte at a time and accumulates it with previous bytes. When term was found, (by default) consumes but discards the term. When EOF was found, (by default) raises same StreamError exception. Then subcon is parsed using new BytesIO made with said data. Building builds the subcon and then writes the term. Size is undefined. The term can be multiple bytes, to support string classes with UTF16/32 encodings for example. Be warned however: as reported in Issue 1046, the data read must be a multiple of the term length and the term must start at a unit boundary, otherwise strange things happen when parsing. :param subcon: Construct instance :param term: optional, bytes, terminator byte-string, default is \x00 single null byte :param include: optional, bool, if to include terminator in resulting data, default is False :param consume: optional, bool, if to consume terminator or leave it in the stream, default is True :param require: optional, bool, if EOF results in failure or not, default is True :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: encountered EOF but require is not disabled :raises PaddingError: terminator is less than 1 bytes in length Example:: >>> d = NullTerminated(Byte) >>> d.parse(b'\xff\x00') 255 >>> d.build(255) b'\xff\x00' r FTc s( t � �|� || _|| _|| _|| _d S r2 )r r r �include�consume�require)r r� r r0 r1 r2 r r r r � s zNullTerminated.__init__c C s� | j }t|�}|dk r"td|d��d}t||�}zt|||�}W n ty` | jrX� nY q�Y n0 ||kr�| jrx||7 }| js�t || d|� q�||7 }q0t |||�} | j � | ||�S )NrP z+NullTerminated term must be at least 1 byter7 rp ) r r: r+ rJ r> r r2 r0 r1 rH rR r� r� ) r r; r� r r r� r= rF r� r r r r r� � s* zNullTerminated._parsec C s, | j �||||�}t|| jt| j�|� |S r2 )r� r� rD r r: )r r� r; r� r r< r r r r� � s zNullTerminated._buildc C s t |d��d S rE r� r� r r r r� � s zNullTerminated._sizeofc C s@ t | j�dkrt�tf t| j�| j| j| jd�| j� ||���S )NrP )� terminatorr0 r1 Z eos_error) r: r r� r r� r0 r1 r2 r� r r r r r r � s z NullTerminated._emitfulltype)r FTTrz r r r r r � s r c sB e Zd ZdZd � fdd� Zdd� Zdd� Zd d � Zd d � Z� Z S )r a� Restricts parsing to bytes except padding left of EOF. Parsing reads entire stream, then strips the data from right to left of null bytes, then parses subcon using new BytesIO made of said data. Building defers to subcon as-is. Size is undefined, because it reads till EOF. The pad can be multiple bytes, to support string classes with UTF16/32 encodings. :param subcon: Construct instance :param pad: optional, bytes, padding byte-string, default is \x00 single null byte :raises PaddingError: pad is less than 1 bytes in length Example:: >>> d = NullStripped(Byte) >>> d.parse(b'\xff\x00\x00') 255 >>> d.build(255) b'\xff' r c s t � �|� || _d S r2 )r r r )r r� r r r r r � s zNullStripped.__init__c C s� | j }t|�}|dk r"td|d��t||�}t||�}|dkrJ|�|�}npt|�| }t|�} |r�|| d � |d |� kr�| |8 } | | dkr�|| | | � |kr�| |8 } q�|d | � }t|||�} | j�| ||�S )NrP z(NullStripped pad must be at least 1 byter7 r ) r r: r+ rJ r@ r� rR r� r� ) r r; r� r r r� rF r= ZtailunitrN r r r r r� s" zNullStripped._parsec C s | j �||||�S r2 r6 r� r r r r� s zNullStripped._buildc C s t |d��d S rE r� r� r r r r� s zNullStripped._sizeofc C s4 t | j�dkrt�tf dt| j�i| j�||���S )NrP � pad_right)r: r r� r r� r� r r r r r r s zNullStripped._emitfulltype)r rz r r r r r � s r c s@ e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Z� Z S ) � RestreamDataa Parses a field on external data (but does not build). Parsing defers to subcon, but provides it a separate BytesIO stream based on data provided by datafunc (a bytes literal or another BytesIO stream or Construct instances that returns bytes or context lambda). Building does nothing. Size is 0 because as far as other fields see it, this field does not produce or consume any bytes from the stream. :param datafunc: bytes or BytesIO or Construct instance (that parses into bytes) or context lambda, provides data for subcon to parse from :param subcon: Construct instance Can propagate any exception from the lambdas, possibly non-ConstructError. Example:: >>> d = RestreamData(b"\x01", Int8ub) >>> d.parse(b"") 1 >>> d.build(0) b'' >>> d = RestreamData(NullTerminated(GreedyBytes), Int16ub) >>> d.parse(b"\x01\x02\x00") 0x0102 >>> d = RestreamData(FixedSized(2, GreedyBytes), Int16ub) >>> d.parse(b"\x01\x02\x00") 0x0102 c s t � �|� || _d| _d S r8 )r r �datafuncr� )r r6 r� r r r r ; s zRestreamData.__init__c C s^ t | j|�}t|t�r t�|�}t|tj�r0|}t|t�rNt�|�|||��}| j�|||�S r2 ) r� r6 rA rB rY r� r� r� r� )r r; r� r r= rD r r r r� @ s zRestreamData._parsec C s |S r2 r r� r r r r� J s zRestreamData._buildc C s dS r` r r� r r r r� M s zRestreamData._sizeofc C s d| j | j�|�f S )Nzrestream(%r, lambda io: %s))r6 r� r� r� r r r r� P s zRestreamData._emitparse) r r r r r r� r� r� r� r r r r r r5 s r5 c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) ri a. Transforms bytes between the underlying stream and the (fixed-sized) subcon. Parsing reads a specified amount (or till EOF), processes data using a bytes-to-bytes decoding function, then parses subcon using those data. Building does build subcon into separate bytes, then processes it using encoding bytes-to-bytes function, then writes those data into main stream. Size is reported as `decodeamount` or `encodeamount` if those are equal, otherwise its SizeofError. Used internally to implement :class:`~construct.core.Bitwise` :class:`~construct.core.Bytewise` :class:`~construct.core.ByteSwapped` :class:`~construct.core.BitsSwapped` . Possible use-cases include encryption, obfuscation, byte-level encoding. .. warning:: Remember that subcon must consume (or produce) an amount of bytes that is same as `decodeamount` (or `encodeamount`). .. warning:: Do NOT use seeking/telling classes inside Transformed context. :param subcon: Construct instance :param decodefunc: bytes-to-bytes function, applied before parsing subcon :param decodeamount: integer, amount of bytes to read :param encodefunc: bytes-to-bytes function, applied after building subcon :param encodeamount: integer, amount of bytes to write :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: subcon build and encoder transformed more or less than `encodeamount` bytes, if amount is specified :raises StringError: building from non-bytes value, perhaps unicode Can propagate any exception from the lambdas, possibly non-ConstructError. Example:: >>> d = Transformed(Bytes(16), bytes2bits, 2, bits2bytes, 2) >>> d.parse(b"\x00\x00") b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' >>> d = Transformed(GreedyBytes, bytes2bits, None, bits2bytes, None) >>> d.parse(b"\x00\x00") b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' c s( t � �|� || _|| _|| _|| _d S r2 )r r � decodefunc� decodeamount� encodefunc� encodeamount)r r� r7 r8 r9 r: r r r r y s zTransformed.__init__c C sT t | jtd ��rt||�}t | jt�r4t|| j|�}| �|�}| j�t � |�||�S r2 ) rA r8 r r@ r� r> r7 r� r� rY r� rB r r r r� � s zTransformed._parsec C sv t �� }| j�||||�}|�� }| �|�}t| jt�r`t |�| jkr`t dt |�| jf |d��t ||t |�|� |S )NzQencoding transformation produced wrong amount of bytes, %s instead of expected %sr7 ) rY r� r� r� r� r9 rA r: r� r: r rD rC r r r r� � s zTransformed._buildc C s> | j d u s| jd u r t|d��| j | jkr0| jS t|d��d S rE )r8 r: r r� r r r r� � s zTransformed._sizeofr� r r r r ri T s $ ri c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) rl aE Transforms bytes between the underlying stream and the (variable-sized) subcon. Used internally to implement :class:`~construct.core.Bitwise` :class:`~construct.core.Bytewise` :class:`~construct.core.ByteSwapped` :class:`~construct.core.BitsSwapped` . .. warning:: Remember that subcon must consume or produce an amount of bytes that is a multiple of encoding or decoding units. For example, in a Bitwise context you should process a multiple of 8 bits or the stream will fail during parsing/building. .. warning:: Do NOT use seeking/telling classes inside Restreamed context. :param subcon: Construct instance :param decoder: bytes-to-bytes function, used on data chunks when parsing :param decoderunit: integer, decoder takes chunks of this size :param encoder: bytes-to-bytes function, used on data chunks when building :param encoderunit: integer, encoder takes chunks of this size :param sizecomputer: function that computes amount of bytes outputed Can propagate any exception from the lambda, possibly non-ConstructError. Can also raise arbitrary exceptions in RestreamedBytesIO implementation. Example:: Bitwise <--> Restreamed(subcon, bits2bytes, 8, bytes2bits, 1, lambda n: n//8) Bytewise <--> Restreamed(subcon, bytes2bits, 1, bits2bytes, 8, lambda n: n*8) c s. t � �|� || _|| _|| _|| _|| _d S r2 )r r �decoder� decoderunit�encoder� encoderunit� sizecomputer)r r� r; r< r= r> r? r r r r � s zRestreamed.__init__c C s4 t || j| j| j| j�}| j�|||�}|�� |S r2 )�RestreamedBytesIOr; r< r= r> r� r� �close)r r; r� r rD r� r r r r� � s zRestreamed._parsec C s6 t || j| j| j| j�}| j�||||�}|�� |S r2 )r@ r; r< r= r> r� r� rA )r r� r; r� r rD r< r r r r� � s zRestreamed._buildc C s0 | j d u rtd|d��n| � | j�||��S d S )Nz7Restreamed cannot calculate size without a sizecomputerr7 )r? r r� r� r� r r r r� � s zRestreamed._sizeofr� r r r r rl � s rl c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) � ProcessXoraU Transforms bytes between the underlying stream and the subcon. Used internally by KaitaiStruct compiler, when translating `process: xor` tags. Parsing reads till EOF, xors data with the pad, then feeds that data into subcon. Building first builds the subcon into separate BytesIO stream, xors data with the pad, then writes that data into the main stream. Size is the same as subcon, unless it raises SizeofError. :param padfunc: integer or bytes or context lambda, single or multiple bytes to xor data with :param subcon: Construct instance :raises StringError: pad is not integer or bytes Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = ProcessXor(0xf0 or b'\xf0', Int16ub) >>> d.parse(b"\x00\xff") 0xf00f >>> d.sizeof() 2 c s t � �|� || _d S r2 )r r �padfunc)r rC r� r r r r � s zProcessXor.__init__c s� t | j|�� t� ttf�s&td|d��t� t�rDt� �dkrDt� �� t||�}t ||�}t� t�r�� dks�t � fdd�|D ��}t� t�r�t� �dkr�� t t� ��ks�t dd� t |t �� ��D ��}t|||�}| j�|||�S ) N�%ProcessXor needs integer or bytes padr7 rP r c 3 s | ]}|� A V qd S r2 r �rm r� r r r rs � rp z$ProcessXor._parse.<locals>.<genexpr>�@ c s s | ]\}}||A V qd S r2 r �rm r� �pr r r rs � rp )r� rC rA r� rB r r: r� rJ r@ �integers2bytesr^ �zipry �cyclerR r� r� )r r; r� r rF r= r r r r r� � s zProcessXor._parsec s� t | j|�� t� ttf�s&td|d��t� t�rDt� �dkrDt� �� t� � }| j � ||||�}|� � }t� t�r�� dks�t � fdd�|D ��}t� t�r�t� �dkr�� tt� ��ks�t dd� t|t�� ��D ��}t||t|�|� |S ) NrD r7 rP r c 3 s | ]}|� A V qd S r2 r rE r r r rs rp z$ProcessXor._build.<locals>.<genexpr>rF c s s | ]\}}||A V qd S r2 r rG r r r rs rp )r� rC rA r� rB r r: r� rY r� r� r� r� rI r^ rJ ry rK rD rC r r r r� � s zProcessXor._buildc C s | j �||�S r2 r7 r� r r r r� s zProcessXor._sizeofr� r r r r rB � s rB c sL e Zd ZdZdd� edd�D �Z� fdd�Zdd � Zd d � Zd d � Z � Z S )�ProcessRotateLefta� Transforms bytes between the underlying stream and the subcon. Used internally by KaitaiStruct compiler, when translating `process: rol/ror` tags. Parsing reads till EOF, rotates (shifts) the data *left* by amount in bits, then feeds that data into subcon. Building first builds the subcon into separate BytesIO stream, rotates *right* by negating amount, then writes that data into the main stream. Size is the same as subcon, unless it raises SizeofError. :param amount: integer or context lambda, shift by this amount in bits, treated modulo (group x 8) :param group: integer or context lambda, shifting is applied to chunks of this size in bytes :param subcon: Construct instance :raises RotationError: group is less than 1 :raises RotationError: data length is not a multiple of group size Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = ProcessRotateLeft(4, 1, Int16ub) >>> d.parse(b'\x0f\xf0') 0xf00f >>> d = ProcessRotateLeft(4, 2, Int16ub) >>> d.parse(b'\x0f\xf0') 0xff00 >>> d.sizeof() 2 c s$ i | ] � � � fd d�t d�D ��qS )c s$ g | ] }|� > d @ |d� ? B �qS )� r^ r �rm r@ ��amountr r ro 1 rp z'ProcessRotateLeft.<dictcomp>.<listcomp>� )r= )rm r rO r r� 1 rp z ProcessRotateLeft.<dictcomp>rP r^ c s t � �|� || _|| _d S r2 )r r rP �group)r rP rR r� r r r r 3 s zProcessRotateLeft.__init__c sR t | j|�}t | j|���dk r,td|d��|�d }|d �t||�}t|��t|�� dkrntd|d��|dkrxnĈdkr�tj| �t �fdd��D ��}n�|d dkr��fd d �t ��D ��t ��fd d�t dt|���D ��}nP|d � d� ���fd d �t ��D ��t � ���fd d�t dt|���D ��}| j � t �|�||�S )NrP �)group size must be at least 1 to be validr7 r^ r �,data length must be a multiple of group sizec 3 s | ]}� | V qd S r2 r �rm �a�� translater r rs K rp z+ProcessRotateLeft._parse.<locals>.<genexpr>c s g | ]}|� � �qS r r rN �� amount_bytesrR r r ro N rp z,ProcessRotateLeft._parse.<locals>.<listcomp>c 3 s$ | ] }�D ]}� || V q qd S r2 r �rm r@ r� �� data_ints�indicesr r rs O rp c s( g | ] }|� � |d � � f�qS �rP r rN rY r r ro T rp c 3 s@ | ]8}�D ].\}}�|| � > d @ �|| �? B V q qdS �rM Nr �rm r@ Zk1Zk2��amount1�amount2r] � indices_pairsr r rs U rp )r� rP rR r. r@ �bytes2integersr: rL � precomputed_single_rotationsrI r= r� r� rY r� )r r; r� r rP r= r �rc rd rZ r] rR r^ re rX r r� 8 s. &(zProcessRotateLeft._parsec sn t | j|�}t | j|���dk r,td|d��| �d }|d �t�� }| j�||||�}|�� }t |��t |�� dkr�td|d��|dkr�nƈdkr�t j | �t �fdd��D ��}n�|d dk�r��fd d �t��D ��t ��fd d�tdt |���D ��}nP|d � d� ���fd d �t��D ��t � ���fd d�tdt |���D ��}t||t |�|� |S )NrP rS r7 r^ r rT c 3 s | ]}� | V qd S r2 r rU rW r r rs n rp z+ProcessRotateLeft._build.<locals>.<genexpr>c s g | ]}|� � �qS r r rN rY r r ro q rp z,ProcessRotateLeft._build.<locals>.<listcomp>c 3 s$ | ] }�D ]}� || V q qd S r2 r r[ r\ r r rs r rp c s( g | ] }|� � |d � � f�qS r_ r rN rY r r ro w rp c 3 s@ | ]8}�D ].\}}�|| � > d @ �|| �? B V q qdS r` r ra rb r r rs x rp )r� rP rR r. rY r� r� r� r� rf r: rL rg rI r= rD ) r r� r; r� r rP rD r< r= r rh r r� Y s4 &(zProcessRotateLeft._buildc C s | j �||�S r2 r7 r� r r r r� } s zProcessRotateLeft._sizeof) r r r r r= rg r r� r� r� r r r r r rL s !$rL c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) �ChecksumaP Field that is build or validated by a hash of a given byte range. Usually used with :class:`~construct.core.RawCopy` . Parsing compares parsed subcon `checksumfield` with a context entry provided by `bytesfunc` and transformed by `hashfunc`. Building fetches the contect entry, transforms it, then writes is using subcon. Size is same as subcon. :param checksumfield: a subcon field that reads the checksum, usually Bytes(int) :param hashfunc: function that takes bytes and returns whatever checksumfield takes when building, usually from hashlib module :param bytesfunc: context lambda that returns bytes (or object) to be hashed, usually like this.rawcopy1.data :raises ChecksumError: parsing and actual checksum does not match actual data Can propagate any exception from the lambdas, possibly non-ConstructError. Example:: import hashlib d = Struct( "fields" / RawCopy(Struct( Padding(1000), )), "checksum" / Checksum(Bytes(64), lambda data: hashlib.sha512(data).digest(), this.fields.data), ) d.build(dict(fields=dict(value={}))) :: import hashlib d = Struct( "offset" / Tell, "checksum" / Padding(64), "fields" / RawCopy(Struct( Padding(1000), )), "checksum" / Pointer(this.offset, Checksum(Bytes(64), lambda data: hashlib.sha512(data).digest(), this.fields.data)), ) d.build(dict(fields=dict(value={}))) c s& t � �� || _|| _|| _d| _d S r8 )r r � checksumfield�hashfunc� bytesfuncr� )r rj rk rl r r r r � s zChecksum.__init__c C sh | j �|||�}| �| �|��}||krdtdt|t�s:|nt�|�t|t�sP|nt�|�f |d��|S )Nz$wrong checksum, read %r, computed %rr7 ) rj r� rk rl r/ rA rB �binasciir� )r r; r� r Zhash1�hash2r r r r� � s ��zChecksum._parsec C s& | � | �|��}| j�||||� |S r2 )rk rl rj r� )r r� r; r� r rn r r r r� � s zChecksum._buildc C s | j �||�S r2 )rj r� r� r r r r� � s zChecksum._sizeofr� r r r r ri � s * ri c s2 e Zd ZdZd � fdd� Zdd� Zdd� Z� ZS ) � Compressedac Compresses and decompresses underlying stream when processing subcon. When parsing, entire stream is consumed. When building, it puts compressed bytes without marking the end. This construct should be used with :class:`~construct.core.Prefixed` . Parsing and building transforms all bytes using a specified codec. Since data is processed until EOF, it behaves similar to `GreedyBytes`. Size is undefined. :param subcon: Construct instance, subcon used for storing the value :param encoding: string, any of module names like zlib/gzip/bzip2/lzma, otherwise any of codecs module bytes<->bytes encodings, each codec usually requires some Python version :param level: optional, integer between 0..9, although lzma discards it, some encoders allow different compression levels :raises ImportError: needed module could not be imported by ctor :raises StreamError: stream failed when reading until EOF Example:: >>> d = Prefixed(VarInt, Compressed(GreedyBytes, "zlib")) >>> d.build(bytes(100)) b'\x0cx\x9cc`\xa0=\x00\x00\x00d\x00\x01' >>> len(_) 13 Nc s� t � �|� || _|| _| jdkr2dd l}|| _n\| jdkrLdd l}|| _nB| jdkrfdd l}|| _n(| jdkr�dd l}|| _ndd l }|| _d S )N�zlibr �gzip�bzip2�lzma) r r r� �levelrp �librq �bz2rs �codecs) r r� r� rt rp rq rv rs rw r r r r � s" zCompressed.__init__c C s& | j dv r| j�|�S | j�|| j �S )N�rp rq rr rs )r� ru � decompressr� rF r r r r9 � s zCompressed._decodec C sJ | j dv r:| jd u s | j dkr*| j�|�S | j�|| j�S | j�|| j �S )Nrx rs )r� rt ru �compressr� rF r r r r: � s zCompressed._encode)N�r r r r r r9 r: r r r r r ro � s ro c s0 e Zd ZdZ� fdd�Zdd� Zdd� Z� ZS )� CompressedLZ4a� Compresses and decompresses underlying stream before processing subcon. When parsing, entire stream is consumed. When building, it puts compressed bytes without marking the end. This construct should be used with :class:`~construct.core.Prefixed` . Parsing and building transforms all bytes using LZ4 library. Since data is processed until EOF, it behaves similar to `GreedyBytes`. Size is undefined. :param subcon: Construct instance, subcon used for storing the value :raises ImportError: needed module could not be imported by ctor :raises StreamError: stream failed when reading until EOF Can propagate lz4.frame exceptions. Example:: >>> d = Prefixed(VarInt, CompressedLZ4(GreedyBytes)) >>> d.build(bytes(100)) b'"\x04"M\x18h@d\x00\x00\x00\x00\x00\x00\x00#\x0b\x00\x00\x00\x1f\x00\x01\x00KP\x00\x00\x00\x00\x00\x00\x00\x00\x00' >>> len(_) 35 c s t � �|� dd l}|j| _d S r` )r r Z lz4.frame�frameru )r r� Zlz4r r r r s zCompressedLZ4.__init__c C s | j �|�S r2 )ru ry rF r r r r9 s zCompressedLZ4._decodec C s | j �|�S r2 )ru rz rF r r r r: s zCompressedLZ4._encoder{ r r r r r| s r| c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) � EncryptedSyma� Perform symmetrical encryption and decryption of the underlying stream before processing subcon. When parsing, entire stream is consumed. When building, it puts encrypted bytes without marking the end. Parsing and building transforms all bytes using the selected cipher. Since data is processed until EOF, it behaves similar to `GreedyBytes`. Size is undefined. The key for encryption and decryption should be passed via `contextkw` to `build` and `parse` methods. This construct is heavily based on the `cryptography` library, which supports the following algorithms and modes. For more details please see the documentation of that library. Algorithms: - AES - Camellia - ChaCha20 - TripleDES - CAST5 - SEED - SM4 - Blowfish (weak cipher) - ARC4 (weak cipher) - IDEA (weak cipher) Modes: - CBC - CTR - OFB - CFB - CFB8 - XTS - ECB (insecure) .. note:: Keep in mind that some of the algorithms require padding of the data. This can be done e.g. with :class:`~construct.core.Aligned`. .. note:: For GCM mode use :class:`~construct.core.EncryptedSymAead`. :param subcon: Construct instance, subcon used for storing the value :param cipher: Cipher object or context lambda from cryptography.hazmat.primitives.ciphers :raises ImportError: needed module could not be imported :raises StreamError: stream failed when reading until EOF :raises CipherError: no cipher object is provided :raises CipherError: an AEAD cipher is used Can propagate cryptography.exceptions exceptions. Example:: >>> from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes >>> d = Struct( ... "iv" / Default(Bytes(16), os.urandom(16)), ... "enc_data" / EncryptedSym( ... Aligned(16, ... Struct( ... "width" / Int16ul, ... "height" / Int16ul, ... ) ... ), ... lambda ctx: Cipher(algorithms.AES(ctx._.key), modes.CBC(ctx.iv)) ... ) ... ) >>> key128 = b"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" >>> d.build({"enc_data": {"width": 5, "height": 4}}, key=key128) b"o\x11i\x98~H\xc9\x1c\x17\x83\xf6|U:\x1a\x86+\x00\x89\xf7\x8e\xc3L\x04\t\xca\x8a\xc8\xc2\xfb'\xc8" >>> d.parse(b"o\x11i\x98~H\xc9\x1c\x17\x83\xf6|U:\x1a\x86+\x00\x89\xf7\x8e\xc3L\x04\t\xca\x8a\xc8\xc2\xfb'\xc8", key=key128) Container: iv = b'o\x11i\x98~H\xc9\x1c\x17\x83\xf6|U:\x1a\x86' (total 16) enc_data = Container: width = 5 height = 4 c s dd l }t� �|� || _d S r` )� cryptographyr r �cipher)r r� r� r r r r r h s zEncryptedSym.__init__c C s\ ddl m}m} t| j|�}t||�s>tdt|�� d�|d��t|j|j �rXtd|d��|S )Nr )�Cipher�modeszcipher z> is not a cryptography.hazmat.primitives.ciphers.Cipher objectr7 z@AEAD cipher is not supported in this class, use EncryptedSymAead) Z&cryptography.hazmat.primitives.ciphersr� r� r� r� rA r1 r5 �modeZGCM)r r� r r� r� r� r r r �_evaluate_cipherm s z EncryptedSym._evaluate_cipherc C s& | � ||�}|�� }|�|�|�� S r2 )r� � decryptorr� �finalize)r r= r� r r� r� r r r r9 v s zEncryptedSym._decodec C s& | � ||�}|�� }|�|�|�� S r2 )r� � encryptorr� r� )r r= r� r r� r� r r r r: { s zEncryptedSym._encode� r r r r r r� r9 r: r r r r r r~ " s E r~ c s: e Zd ZdZd � fdd� Zdd� Zdd� Zd d � Z� ZS ) �EncryptedSymAeada� Perform symmetrical AEAD encryption and decryption of the underlying stream before processing subcon. When parsing, entire stream is consumed. When building, it puts encrypted bytes and tag without marking the end. Parsing and building transforms all bytes using the selected cipher and also authenticates the `associated_data`. Since data is processed until EOF, it behaves similar to `GreedyBytes`. Size is undefined. The key for encryption and decryption should be passed via `contextkw` to `build` and `parse` methods. This construct is heavily based on the `cryptography` library, which supports the following AEAD ciphers. For more details please see the documentation of that library. AEAD ciphers: - AESGCM - AESCCM - ChaCha20Poly1305 :param subcon: Construct instance, subcon used for storing the value :param cipher: Cipher object or context lambda from cryptography.hazmat.primitives.ciphers :raises ImportError: needed module could not be imported :raises StreamError: stream failed when reading until EOF :raises CipherError: unsupported cipher object is provided Can propagate cryptography.exceptions exceptions. Example:: >>> from cryptography.hazmat.primitives.ciphers import aead >>> d = Struct( ... "nonce" / Default(Bytes(16), os.urandom(16)), ... "associated_data" / Bytes(21), ... "enc_data" / EncryptedSymAead( ... GreedyBytes, ... lambda ctx: aead.AESGCM(ctx._.key), ... this.nonce, ... this.associated_data ... ) ... ) >>> key128 = b"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" >>> d.build({"associated_data": b"This is authenticated", "enc_data": b"The secret message"}, key=key128) b'\xe3\xb0"\xbaQ\x18\xd3|\x14\xb0q\x11\xb5XZ\xeeThis is authenticated\x88~\xe5Vh\x00\x01m\xacn\xad k\x02\x13\xf4\xb4[\xbe\x12$\xa0\x7f\xfb\xbf\x82Ar\xb0\x97C\x0b\xe3\x85' >>> d.parse(b'\xe3\xb0"\xbaQ\x18\xd3|\x14\xb0q\x11\xb5XZ\xeeThis is authenticated\x88~\xe5Vh\x00\x01m\xacn\xad k\x02\x13\xf4\xb4[\xbe\x12$\xa0\x7f\xfb\xbf\x82Ar\xb0\x97C\x0b\xe3\x85', key=key128) Container: nonce = b'\xe3\xb0"\xbaQ\x18\xd3|\x14\xb0q\x11\xb5XZ\xee' (total 16) associated_data = b'This is authenti'... (truncated, total 21) enc_data = b'The secret messa'... (truncated, total 18) rp c s" t � �|� || _|| _|| _d S r2 )r r r� �nonce�associated_data)r r� r� r� r� r r r r � s zEncryptedSymAead.__init__c C sL ddl m}m}m} t| j|�}t||||f�sHtdt|�� d�|d��|S )Nr )�AESGCM�AESCCM�ChaCha20Poly1305zcipher object z is not supportedr7 ) Z+cryptography.hazmat.primitives.ciphers.aeadr� r� r� r� r� rA r1 r5 )r r� r r� r� r� r� r r r r� � s z!EncryptedSymAead._evaluate_cipherc C s2 | � ||�}t| j|�}t| j|�}|�|||�S r2 )r� r� r� r� Zdecrypt�r r= r� r r� r� r� r r r r9 � s zEncryptedSymAead._decodec C s2 | � ||�}t| j|�}t| j|�}|�|||�S r2 )r� r� r� r� Zencryptr� r r r r: � s zEncryptedSymAead._encode)rp r� r r r r r� � s .r� c s2 e Zd ZdZd � fdd� Zdd� Zdd� Z� ZS ) � Rebuffereda^ Caches bytes from underlying stream, so it becomes seekable and tellable, and also becomes blocking on reading. Useful for processing non-file streams like pipes, sockets, etc. .. warning:: Experimental implementation. May not be mature enough. :param subcon: Construct instance, subcon which will operate on the buffered stream :param tailcutoff: optional, integer, amount of bytes kept in buffer, by default buffers everything Can also raise arbitrary exceptions in its implementation. Example:: Rebuffered(..., tailcutoff=1024).parse_stream(nonseekable_stream) Nc s t � �|� td |d�| _d S )N)� tailcutoff)r r ZRebufferedBytesIOrD )r r� r� r r r r � s zRebuffered.__init__c C s || j _| j�| j ||�S r2 )rD r r� r� r� r r r r� � s zRebuffered._parsec C s || j _| j�|| j ||�S r2 )rD r r� r� r� r r r r� � s zRebuffered._build)Nr� r r r r r� � s r� c s0 e Zd ZdZ� fdd�Zdd� Zdd� Z� ZS )�Lazya Lazyfies a field. This wrapper allows you to do lazy parsing of individual fields inside a normal Struct (without using LazyStruct which may not work in every scenario). It is also used by KaitaiStruct compiler to emit `instances` because those are not processed greedily, and they may refer to other not yet parsed fields. Those are 2 entirely different applications but semantics are the same. Parsing saves the current stream offset and returns a lambda. If and when that lambda gets evaluated, it seeks the stream to then-current position, parses the subcon, and seeks the stream back to previous position. Building evaluates that lambda into an object (if needed), then defers to subcon. Size also defers to subcon. :param subcon: Construct instance :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes :raises StreamError: stream is not seekable and tellable Example:: >>> d = Lazy(Byte) >>> x = d.parse(b'\x00') >>> x <function construct.core.Lazy._parse.<locals>.execute> >>> x() 0 >>> d.build(0) b'\x00' >>> d.build(x) b'\x00' >>> d.sizeof() 1 c s t � �|� d S r2 �r r r4 r r r r s z Lazy.__init__c s@ t ����� ����fdd�}�j��� ��}t�|d�� |S )Nc s: t ���} t��d�� �j��� ��}t�| d�� |S r` )rJ rH r� r� )rM r� �r� rF r r r; r r �execute s z Lazy._parse.<locals>.executerP )rJ r� r� rH )r r; r� r r� r: r r� r r� s z Lazy._parsec C s t |�r|� }| j�||||�S r2 )r� r� r� r� r r r r� s z Lazy._buildr� r r r r r� � s r� c @ s\ e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z eZ dd� Z dd� Z dS )� LazyContainerr� c C s( || _ || _|| _|| _|| _|| _d S r2 )�_struct�_stream�_offsets�_values�_context�_path)r ru r; �offsetsr� r� r r r r r s zLazyContainer.__init__c C s || j jv r| | S t�d S r2 )r� �_subconsindexesrQ r r r r r+ ' s zLazyContainer.__getattr__c C sl t |t�r| jj| }|| jv r*| j| S t| j| j| d| j� | jj | � | j| j | j�}|| j|< |S r` ) rA r! r� r� r� rH r� r� r� r' r� r� �r r� r� r r r r1 , s zLazyContainer.__getitem__c C s t | jj�S r2 )r: r� r' rX r r r �__len__6 s zLazyContainer.__len__c C s t | jj�S r2 )rk r� rH rX r r r �keys9 s zLazyContainer.keysc s � fdd�� j jD �S )Nc 3 s | ]}� | V qd S r2 r �rm r� rX r r rs = rp z'LazyContainer.values.<locals>.<genexpr>�r� rH rX r rX r r� < s zLazyContainer.valuesc s � fdd�� j jD �S )Nc 3 s | ]}|� | fV qd S r2 r r� rX r r rs @ rp z&LazyContainer.items.<locals>.<genexpr>r� rX r rX r r� ? s zLazyContainer.itemsc C s t �| |�S r2 )r� �__eq__r" r r r r� D s zLazyContainer.__eq__c C s dt | j�t | jj�f S )Nz,<LazyContainer: %s items cached, %s subcons>)r: r� r� r' rX r r r r� G s zLazyContainer.__repr__N)r r r r r r+ r1 r� r� r� r� �__iter__r� r� r r r r r� s r� c s@ e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Zd d � Z� Z S ) � LazyStructa Equivalent to :class:`~construct.core.Struct`, but when this class is parsed, most fields are not parsed (they are skipped if their size can be measured by _actualsize or _sizeof method). See its docstring for details. Fields are parsed depending on some factors: * Some fields like Int* Float* Bytes(5) Array(5,Byte) Pointer are fixed-size and are therefore skipped. Stream is not read. * Some fields like Bytes(this.field) are variable-size but their size is known during parsing when there is a corresponding context entry. Those fields are also skipped. Stream is not read. * Some fields like Prefixed PrefixedArray PascalString are variable-size but their size can be computed by partially reading the stream. Only first few bytes are read (the lengthfield). * Other fields like VarInt need to be parsed. Stream position that is left after the field was parsed is used. * Some fields may not work properly, due to the fact that this class attempts to skip fields, and parses them only out of necessity. Miscellaneous fields often have size defined as 0, and fixed sized fields are skippable. Note there are restrictions: * If a field like Bytes(this.field) references another field in the same struct, you need to access the referenced field first (to trigger its parsing) and then you can access the Bytes field. Otherwise it would fail due to missing context entry. * If a field references another field within inner (nested) or outer (super) struct, things may break. Context is nested, but this class was not rigorously tested in that manner. Building and sizeof are greedy, like in Struct. :param \*subcons: Construct instances, list of members, some can be anonymous :param \*\*subconskw: Construct instances, list of members (requires Python 3.6) c st t � �� t|�tdd� |�� D �� | _tdd� | jD ��| _tdd� t| j�D ��| _t dd� | jD ��| _ d S )Nc s s | ]\}}|| V qd S r2 r r� r r r rs d rp z&LazyStruct.__init__.<locals>.<genexpr>c s s | ]}|j r|j |fV qd S r2 rD rE r r r rs e rp c s s" | ]\}}|j r|j |fV qd S r2 rD r� r r r rs f rp c s s | ] }|j V qd S r2 rF rE r r r rs g rp ) r r rs r� r' r� rH rl r� rI r� rJ r r r r b s zLazyStruct.__init__c C s || j v r| j | S t�d S r2 rL r r r r r+ i s zLazyStruct.__getattr__c C s� t ||jd |j|j|j| j||�dd �d� }|j�d|�|_t ||�}d|i}i }t | j �D ]|\}}z$||� |||�7 }t ||d|� W nB ty� |�|||�} | ||< |jr�| ||j< t ||�}Y n0 |||d < q\t| |||||�S )NrN rO rP r rP )r� r� r� r� r� rH r> r rP rJ rl r' r� rH r r� r� r� ) r r; r� r rF r� r� r@ r� r� r r r r� n s" , zLazyStruct._parsec C s� |d u rt � }t ||jd |j|j|j| j||�dd �d� }|j�d|�|_|� |� | j D ]r}zT|j rv|�|j d �}n ||j }|j r�|||j < |� ||||�}|j r�|||j < W qZ ty� Y q�Y qZ0 qZ|S rM rT rU r r r r� � s$ , zLazyStruct._buildc s� t � � jd � j� j� j| jd � �dd �d� � � j�d� �� _z t � �fdd�| j D ��W S t t fyz t d�d��Y n0 d S )NrN rO rP c 3 s | ]}|� � ��V qd S r2 r� rE rV r r rs � rp z%LazyStruct._sizeof.<locals>.<genexpr>rO r7 rW r� r rV r r� � s , zLazyStruct._sizeof) r r r r r r+ r� r� r� r r r r r r� K s r� c @ sH e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dS )�LazyListContainerr� c C s. || _ || _|| _|| _|| _|| _|| _d S r2 )�_subconr� �_countr� r� r� r� )r r� r; r0 r� r� r� r r r r r � s zLazyListContainer.__init__c sx t |t�r(� fdd�t|�� j�� D �S |� jv r<� j| S t� j� j| d� j � � j � � j� j � j �}|� j|< |S )Nc s g | ] }� | �qS r r rN rX r r ro � rp z1LazyListContainer.__getitem__.<locals>.<listcomp>r ) rA r. r= r^ r� r� rH r� r� r� r� r� r� r� r rX r r1 � s z LazyListContainer.__getitem__c C s |t jkr| j}| �t||��S r2 )r� �maxsizer� r1 r. )r �start�stopr r r � __getslice__� s z LazyListContainer.__getslice__c C s | j S r2 )r� rX r r r r� � s zLazyListContainer.__len__c s � fdd�t � j�D �S )Nc 3 s | ]}� | V qd S r2 r rN rX r r rs � rp z-LazyListContainer.__iter__.<locals>.<genexpr>)r= r� rX r rX r r� � s zLazyListContainer.__iter__c s. t ��t � �ko,t� �fdd�t�j�D ��S )Nc 3 s | ]}�| � | kV qd S r2 r rN �r# r r r rs � rp z+LazyListContainer.__eq__.<locals>.<genexpr>)r: rI r= r� r" r r� r r� � s zLazyListContainer.__eq__c C s dt | j�| jf S )Nz*<LazyListContainer: %s of %s items cached>)r: r� r� rX r r r r� � s zLazyListContainer.__repr__N) r r r r r r1 r� r� r� r� r� r r r r r� � s r� c s8 e Zd ZdZ� fdd�Zdd� Zdd� Zdd � Z� ZS ) � LazyArraya� Equivalent to :class:`~construct.core.Array`, but the subcon is not parsed when possible (it gets skipped if the size can be measured by _actualsize or _sizeof method). See its docstring for details. Fields are parsed depending on some factors: * Some fields like Int* Float* Bytes(5) Array(5,Byte) Pointer are fixed-size and are therefore skipped. Stream is not read. * Some fields like Bytes(this.field) are variable-size but their size is known during parsing when there is a corresponding context entry. Those fields are also skipped. Stream is not read. * Some fields like Prefixed PrefixedArray PascalString are variable-size but their size can be computed by partially reading the stream. Only first few bytes are read (the lengthfield). * Other fields like VarInt need to be parsed. Stream position that is left after the field was parsed is used. * Some fields may not work properly, due to the fact that this class attempts to skip fields, and parses them only out of necessity. Miscellaneous fields often have size defined as 0, and fixed sized fields are skippable. Note there are restrictions: * If a field references another field within inner (nested) or outer (super) struct, things may break. Context is nested, but this class was not rigorously tested in that manner. Building and sizeof are greedy, like in Array. :param count: integer or context lambda, strict amount of elements :param subcon: Construct instance, subcon to process individual elements c s t � �|� || _d S r2 )r r r0 )r r0 r� r r r r � s zLazyArray.__init__c C s� | j }| j}t|�r ||�}d|ks6td|f |d��t||�}d|i}i }t|�D ]h} z$||�|||�7 }t||d|� W n2 ty� |� |||�} | || < t||�}Y n0 ||| d < qTt |||||||�S )Nr rr r7 rP ) r� r0 r� r rJ r= r� rH r r� r� ) r r; r� r r� r0 rF r� r� r@ r� r r r r� � s& zLazyArray._parsec C s� | j }t|�r||�}d|ks0td|f |d��t|�|ksTtd|t|�f |d��t� }t|�D ]*\}}||_| j�||||�} |� | � qb|S rs ) r0 r� r r: rj rl rN r� r� rw ) r r� r; r� r r0 rn r@ r� r< r r r r� � s zLazyArray._buildc C sP z| j }t|�r||�}W n" ttfy< td|d��Y n0 || j�||� S rN )r0 r� rP rQ r r� r� rt r r r r� s zLazyArray._sizeofr� r r r r r� � s r� c s0 e Zd ZdZ� fdd�Zdd� Zdd� Z� ZS )� LazyBounda� Field that binds to the subcon only at runtime (during parsing and building, not ctor). Useful for recursive data structures, like linked-lists and trees, where a construct needs to refer to itself (while it does not exist yet in the namespace). Note that it is possible to obtain same effect without using this class, using a loop. However there are usecases where that is not possible (if remaining nodes cannot be sized-up, and there is data following the recursive structure). There is also a significant difference, namely that LazyBound actually does greedy parsing while the loop does lazy parsing. See examples. To break recursion, use `If` field. See examples. :param subconfunc: parameter-less lambda returning Construct instance, can also return itself Example:: d = Struct( "value" / Byte, "next" / If(this.value > 0, LazyBound(lambda: d)), ) >>> print(d.parse(b"\x05\x09\x00")) Container: value = 5 next = Container: value = 9 next = Container: value = 0 next = None :: d = Struct( "value" / Byte, "next" / GreedyBytes, ) data = b"\x05\x09\x00" while data: x = d.parse(data) data = x.next print(x) # print outputs Container: value = 5 next = \t\x00 (total 2) # print outputs Container: value = 9 next = \x00 (total 1) # print outputs Container: value = 0 next = (total 0) c s t � �� || _d S r2 )r r � subconfunc)r r� r r r r G s zLazyBound.__init__c C s | � � }|�|||�S r2 )r� r� )r r; r� r r� r r r r� K s zLazyBound._parsec C s | � � }|�||||�S r2 )r� r� )r r� r; r� r r� r r r r� O s zLazyBound._buildr� r r r r r� s 1 r� c s e Zd ZdZ� fdd�Z� ZS )� ExprAdapteraJ Generic adapter that takes `decoder` and `encoder` lambdas as parameters. You can use ExprAdapter instead of writing a full-blown class deriving from Adapter when only a simple lambda is needed. :param subcon: Construct instance, subcon to adapt :param decoder: lambda that takes (obj, context) and returns an decoded version of obj :param encoder: lambda that takes (obj, context) and returns an encoded version of obj Example:: >>> d = ExprAdapter(Byte, obj_+1, obj_-1) >>> d.parse(b'\x04') 5 >>> d.build(5) b'\x04' c s, t � �|� � fdd�| _�fdd�| _d S )Nc s � | |�S r2 r �r� �ctxr )r; r r r� i rp z&ExprAdapter.__init__.<locals>.<lambda>c s � | |�S r2 r r� )r= r r r� j rp )r r r9 r: )r r� r; r= r )r; r= r r g s zExprAdapter.__init__r r r r r r� W s r� c s e Zd ZdZ� fdd�Z� ZS )�ExprSymmetricAdapteru Macro around :class:`~construct.core.ExprAdapter`. :param subcon: Construct instance, subcon to adapt :param encoder: lambda that takes (obj, context) and returns both encoded version and decoded version of obj Example:: >>> d = ExprSymmetricAdapter(Byte, obj_ & 0b00001111) >>> d.parse(b"ÿ") 15 >>> d.build(255) b'' c s t � �|||� d S r2 r� )r r� r= r r r r | s z ExprSymmetricAdapter.__init__r r r r r r� m s r� c s e Zd ZdZ� fdd�Z� ZS )� ExprValidatora Generic adapter that takes `validator` lambda as parameter. You can use ExprValidator instead of writing a full-blown class deriving from Validator when only a simple lambda is needed. :param subcon: Construct instance, subcon to adapt :param validator: lambda that takes (obj, context) and returns a bool Example:: >>> d = ExprValidator(Byte, obj_ & 0b11111110 == 0) >>> d.build(1) b'\x01' >>> d.build(88) ValidationError: object failed validation: 88 c s t � �|� � fdd�| _d S )Nc s � | |�S r2 r r� �� validatorr r r� � rp z(ExprValidator.__init__.<locals>.<lambda>)r r r@ )r r� r� r r� r r � s zExprValidator.__init__r r r r r r� � s r� c s t | � fdd��S )a: Validates that the object is one of the listed values, both during parsing and building. .. note:: For performance, `valids` should be a set or frozenset. :param subcon: Construct instance, subcon to validate :param valids: collection implementing __contains__, usually a list or set :raises ValidationError: parsed or build value is not among valids Example:: >>> d = OneOf(Byte, [1,2,3]) >>> d.parse(b"\x01") 1 >>> d.parse(b"\xff") construct.core.ValidationError: object failed validation: 255 c s | � v S r2 r �r� r� ��validsr r r� � rp zOneOf.<locals>.<lambda>�r� )r� r� r r� r �OneOf� s r� c s t | � fdd��S )a} Validates that the object is none of the listed values, both during parsing and building. .. note:: For performance, `valids` should be a set or frozenset. :param subcon: Construct instance, subcon to validate :param invalids: collection implementing __contains__, usually a list or set :raises ValidationError: parsed or build value is among invalids c s | � vS r2 r r� ��invalidsr r r� � rp zNoneOf.<locals>.<lambda>r� )r� r� r r� r �NoneOf� s r� c s t |� fdd��S )a� Filters a list leaving only the elements that passed through the predicate. :param subcon: Construct instance, usually Array GreedyRange Sequence :param predicate: lambda that takes (obj, context) and returns a bool Can propagate any exception from the lambda, possibly non-ConstructError. Example:: >>> d = Filter(obj_ != 0, Byte[:]) >>> d.parse(b"\x00\x02\x00") [2] >>> d.build([0,1,0,2,0]) b'\x01\x02' c s � �fdd�| D �S )Nc s g | ]}�|� �r|�qS r r )rm r4 )r� r| r r ro � rp z,Filter.<locals>.<lambda>.<locals>.<listcomp>r r� r~ )r� r r� � rp zFilter.<locals>.<lambda>)r� )r| r� r r~ r �Filter� s r� c s2 e Zd ZdZd � fdd� Zdd� Zdd � Z� ZS ) �Slicinga� Adapter for slicing a list. Works with GreedyRange and Sequence. :param subcon: Construct instance, subcon to slice :param count: integer, expected number of elements, needed during building :param start: integer for start index (or None for entire list) :param stop: integer for stop index (or None for up-to-end) :param step: integer, step (or 1 for every element) :param empty: object, value to fill the list with, during building Example:: d = Slicing(Array(4,Byte), 4, 1, 3, empty=0) assert d.parse(b"\x01\x02\x03\x04") == [2,3] assert d.build([2,3]) == b"\x00\x02\x03\x00" assert d.sizeof() == 4 rP Nc s. t � �|� || _|| _|| _|| _|| _d S r2 )r r r0 r� r� �step�empty)r r� r0 r� r� r� r� r r r r � s zSlicing.__init__c C s || j | j| j� S r2 )r� r� r� r= r r r r9 � s zSlicing._decodec C s` | j d u r|S | jd u r:| jg| j }||| j d | j�< n"| jg| j }||| j | j| j�< |S r2 )r� r� r� r0 r� �r r� r� r r r r r r: � s zSlicing._encode)rP Nr{ r r r r r� � s r� c s2 e Zd ZdZd � fdd� Zdd� Zdd� Z� ZS ) �IndexingaM Adapter for indexing a list (getting a single item from that list). Works with Range and Sequence and their lazy equivalents. :param subcon: Construct instance, subcon to index :param count: integer, expected number of elements, needed during building :param index: integer, index of the list to get :param empty: object, value to fill the list with, during building Example:: d = Indexing(Array(4,Byte), 4, 2, empty=0) assert d.parse(b"\x01\x02\x03\x04") == 3 assert d.build(3) == b"\x00\x00\x03\x00" assert d.sizeof() == 4 Nc s" t � �|� || _|| _|| _d S r2 )r r r0 r� r� )r r� r0 r� r� r r r r s zIndexing.__init__c C s || j S r2 )r� r= r r r r9 s zIndexing._decodec C s | j g| j }||| j< |S r2 )r� r0 r� r� r r r r: s zIndexing._encode)Nr{ r r r r r� � s r� )r )�ru rY rm ry r� r� r� �osr� r� Zimportlib.machinery�importlib.utilZ construct.libZconstruct.exprZconstruct.versionr9 r r r r r r r r r r r r! r" r# r$ r% r& r' r( r) r* r+ r, r- r. r/ r0 r1 r5 r> r@ rD rH rJ rO rQ r� rR r_ r{ r� r� r� r� r� r� r2 r8 r> r? rA rG rJ rZ ro rq rr r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� ZByteZShortZInt�Longr� r� r� r� r� r� r� r� r� ZHalf�Single�Doubler� r� r� r� r� r� r� r� r� r� r r� r� r r r r r r r\ r r] r r" r3 r5 rA r& r, r/ rx r{ r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r� r r r� r r r r r r� r r! r& r' r r. r r r r5 ri rl rB rL ri ro r| r~ r� r� r� r� r� rs r� r� r� r� r� r� r� r� r� r� r� r r r r �<module> s ` S D%3+O\r 1, �$ !"X ^2 ( %MCjAF7)233+ D F<: >9 :M9'VI Q>.4''"8 H 4@I:4G5CnG8"_I 2/X(JB '
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