mirror of
https://github.com/LonamiWebs/Telethon.git
synced 2024-11-10 19:46:36 +03:00
126 lines
3.6 KiB
Python
126 lines
3.6 KiB
Python
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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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 ValueError("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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def read_byte(self):
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"""Reads a single byte value"""
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return self.reader.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.reader.read(4), byteorder='big', 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.reader.read(8), byteorder='big', signed=signed)
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# Network is always big-endian, this is, '>'
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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.reader.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.reader.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.reader.read(bits // 8), byteorder='big', signed=signed)
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def read(self, length):
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"""Read the given amount of bytes"""
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return self.reader.read(length)
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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_object(self):
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"""Reads a Telegram object"""
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id = self.read_int()
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clazz = tlobjects.get(id, None)
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if clazz is None:
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raise ImportError('Could not find a matching ID for the TLObject that was supposed to be read. '
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'Found ID: {}'.format(hex(id)))
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# Instantiate the class and return the result
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result = clazz()
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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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# TODO Do I need to close the underlying stream?
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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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