75 lines
2.1 KiB
Python
75 lines
2.1 KiB
Python
import struct
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class DataInputStream:
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def __init__(self, buffer: bytes):
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self._buffer = buffer
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self._cursor = 0
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def read_bytes(self, n: int) -> bytes:
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if self._cursor + n > len(self._buffer):
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raise EOFError('stream overread')
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blob = self._buffer[self._cursor : self._cursor + n]
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self._cursor += n
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return blob
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def empty(self):
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return self._cursor >= len(self._buffer) - 1
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def end(self) -> bytes:
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return self.read_bytes(len(self._buffer) - self._cursor)
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def read_byte(self) -> int:
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if self._cursor >= len(self._buffer):
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raise EOFError('stream overread')
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self._cursor += 1
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return self._buffer[self._cursor - 1]
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def read_boolean(self) -> bool:
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return self.read_byte() != 0
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def read_short(self) -> int:
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return struct.unpack('>h', self.read_bytes(2))[0]
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def read_ushort(self) -> int:
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return struct.unpack('>H', self.read_bytes(2))[0]
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def read_int(self) -> int:
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return struct.unpack('>i', self.read_bytes(4))[0]
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def read_uint(self) -> int:
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return struct.unpack('>I', self.read_bytes(4))[0]
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def read_long(self) -> int:
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return struct.unpack('>q', self.read_bytes(8))[0]
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def read_ulong(self) -> int:
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return struct.unpack('>Q', self.read_bytes(8))[0]
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def read_float(self) -> float:
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return struct.unpack('>f', self.read_bytes(4))[0]
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def read_double(self) -> float:
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return struct.unpack('>d', self.read_bytes(8))[0]
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def read_char(self) -> str:
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return chr(self.read_ushort())
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def read_varint(self, bits: int = 32) -> int:
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value: int = 0
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position: int = 0
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while True:
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byte = self.read_byte()
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value |= (byte & 0x7F) << position
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if ((byte & 0x80) == 0):
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break
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position += 7
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if position >= bits:
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raise ValueError('varint too big')
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return value
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def read_string(self) -> str:
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size = self.read_short()
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print(f'read_bytes({size=})')
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return self.read_bytes(size).decode('utf-8')
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