mirror of
https://github.com/LonamiWebs/Telethon.git
synced 2024-11-22 17:36:34 +03:00
146 lines
4.5 KiB
Python
Executable File
146 lines
4.5 KiB
Python
Executable File
from io import BytesIO, BufferedReader
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from tl.all_tlobjects import tlobjects
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from struct import unpack
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from errors import *
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import inspect
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import os
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class BinaryReader:
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"""
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Small utility class to read binary data.
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Also creates a "Memory Stream" if necessary
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"""
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def __init__(self, data=None, stream=None):
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if data:
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self.stream = BytesIO(data)
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elif stream:
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self.stream = stream
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else:
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raise InvalidParameterError("Either bytes or a stream must be provided")
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self.reader = BufferedReader(self.stream)
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# region Reading
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# "All numbers are written as little endian." |> Source: https://core.telegram.org/mtproto
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def read_byte(self):
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"""Reads a single byte value"""
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return self.read(1)[0]
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def read_int(self, signed=True):
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"""Reads an integer (4 bytes) value"""
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return int.from_bytes(self.read(4), byteorder='little', signed=signed)
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def read_long(self, signed=True):
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"""Reads a long integer (8 bytes) value"""
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return int.from_bytes(self.read(8), byteorder='little', signed=signed)
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def read_float(self):
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"""Reads a real floating point (4 bytes) value"""
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return unpack('<f', self.read(4))[0]
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def read_double(self):
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"""Reads a real floating point (8 bytes) value"""
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return unpack('<d', self.read(8))[0]
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def read_large_int(self, bits, signed=True):
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"""Reads a n-bits long integer value"""
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return int.from_bytes(self.read(bits // 8), byteorder='little', signed=signed)
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def read(self, length):
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"""Read the given amount of bytes"""
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result = self.reader.read(length)
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if len(result) != length:
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raise BufferError('Trying to read outside the data bounds (no more data left to read)')
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return result
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def get_bytes(self):
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"""Gets the byte array representing the current buffer as a whole"""
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return self.stream.getvalue()
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# endregion
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# region Telegram custom reading
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def tgread_bytes(self):
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"""Reads a Telegram-encoded byte array, without the need of specifying its length"""
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first_byte = self.read_byte()
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if first_byte == 254:
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length = self.read_byte() | (self.read_byte() << 8) | (self.read_byte() << 16)
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padding = length % 4
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else:
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length = first_byte
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padding = (length + 1) % 4
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data = self.read(length)
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if padding > 0:
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padding = 4 - padding
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self.read(padding)
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return data
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def tgread_string(self):
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"""Reads a Telegram-encoded string"""
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return str(self.tgread_bytes(), encoding='utf-8')
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def tgread_bool(self):
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"""Reads a Telegram boolean value"""
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value = self.read_int(signed=False)
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if value == 0x997275b5: # boolTrue
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return True
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elif value == 0xbc799737: # boolFalse
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return False
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else:
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raise ValueError('Invalid boolean code {}'.format(hex(value)))
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def tgread_object(self):
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"""Reads a Telegram object"""
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constructor_id = self.read_int(signed=False)
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clazz = tlobjects.get(constructor_id, None)
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if clazz is None:
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raise TypeNotFoundError(constructor_id)
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# Now we need to determine the number of parameters of the class, so we can
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# instantiate it with all of them set to None, and still, no need to write
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# the default =None in all the classes, thus forcing the user to provide a real value
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sig = inspect.signature(clazz.__init__)
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params = [None] * (len(sig.parameters) - 1) # Subtract 1 (self)
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result = clazz(*params) # https://docs.python.org/3/tutorial/controlflow.html#unpacking-argument-lists
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# Finally, read the object and return the result
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result.on_response(self)
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return result
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# endregion
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def close(self):
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self.reader.close()
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# region Position related
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def tell_position(self):
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"""Tells the current position on the stream"""
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return self.reader.tell()
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def set_position(self, position):
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"""Sets the current position on the stream"""
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self.reader.seek(position)
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def seek(self, offset):
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"""Seeks the stream position given an offset from the current position. May be negative"""
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self.reader.seek(offset, os.SEEK_CUR)
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# endregion
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# region with block
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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self.close()
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# endregion
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