mirror of
https://github.com/LonamiWebs/Telethon.git
synced 2024-09-21 11:18:50 +03:00
122 lines
3.7 KiB
Python
122 lines
3.7 KiB
Python
from io import BytesIO, BufferedWriter
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from struct import pack
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class BinaryWriter:
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"""
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Small utility class to write binary data.
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Also creates a "Memory Stream" if necessary
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"""
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def __init__(self, stream=None):
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if not stream:
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stream = BytesIO()
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self.stream = stream
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self.writer = BufferedWriter(self.stream)
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# region Writing
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def write_byte(self, value):
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"""Writes a single byte value"""
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self.writer.write(pack('B', value))
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def write_int(self, value, signed=True):
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"""Writes an integer value (4 bytes), which can or cannot be signed"""
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if signed:
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self.writer.write(pack('i', value))
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else:
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value &= 0xFFFFFFFF # Ensure it's unsigned (see http://stackoverflow.com/a/30092291/4759433)
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self.writer.write(pack('I', value))
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def write_long(self, value, signed=True):
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"""Writes a long integer value (8 bytes), which can or cannot be signed"""
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if signed:
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self.writer.write(pack('q', value))
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else:
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value &= 0xFFFFFFFFFFFFFFFF
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self.writer.write(pack('Q', value))
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def write_float(self, value):
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"""Writes a floating point value (4 bytes)"""
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self.writer.write(pack('f', value))
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def write_double(self, value):
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"""Writes a floating point value (8 bytes)"""
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self.writer.write(pack('d', value))
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def write_large_int(self, value, bits):
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"""Writes a n-bits long integer value"""
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self.writer.write(pack('{}B'.format(bits // 8), value))
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def write(self, data):
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"""Writes the given bytes array"""
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self.writer.write(data)
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# endregion
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# region Telegram custom writing
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def tgwrite_bytes(self, data):
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"""Write bytes by using Telegram guidelines"""
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if len(data) < 254:
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padding = (len(data) + 1) % 4
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if padding != 0:
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padding = 4 - padding
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self.write(bytes([len(data)]))
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self.write(data)
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else:
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padding = len(data) % 4
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if padding != 0:
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padding = 4 - padding
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# TODO ensure that _this_ is right (it appears to be)
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self.write(bytes([254]))
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self.write(bytes([len(data) % 256]))
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self.write(bytes([(len(data) >> 8) % 256]))
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self.write(bytes([(len(data) >> 16) % 256]))
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self.write(data)
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""" Original:
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binaryWriter.Write((byte)254);
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binaryWriter.Write((byte)(bytes.Length));
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binaryWriter.Write((byte)(bytes.Length >> 8));
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binaryWriter.Write((byte)(bytes.Length >> 16));
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"""
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self.write(bytes(padding))
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def tgwrite_string(self, string):
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"""Write a string by using Telegram guidelines"""
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return self.tgwrite_bytes(string.encode('utf-8'))
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def tgwrite_bool(self, bool):
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"""Write a boolean value by using Telegram guidelines"""
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# boolTrue boolFalse
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return self.write_int(0x997275b5 if bool else 0xbc799737, signed=False)
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# endregion
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def flush(self):
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"""Flush the current stream to "update" changes"""
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self.writer.flush()
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def close(self):
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"""Close the current stream"""
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self.writer.close()
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# TODO Do I need to close the underlying stream?
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def get_bytes(self, flush=True):
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"""Get the current bytes array content from the buffer, optionally flushing first"""
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if flush:
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self.writer.flush()
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self.stream.getbuffer()
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# 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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