mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-11-15 20:19:23 +00:00
48 lines
1.1 KiB
Python
48 lines
1.1 KiB
Python
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if False:
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from typing import Optional
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class BytearrayReader:
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def __init__(self, data: bytes):
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self.data = data
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self.offset = 0
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def get(self) -> int:
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ret = self.data[self.offset]
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self.offset += 1
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return ret
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def peek(self) -> int:
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return self.data[self.offset]
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def read(self, i: Optional[int] = None) -> bytes:
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if i is None:
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ret = self.data[self.offset :]
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self.offset = len(self.data)
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elif 0 <= i <= len(self.data) - self.offset:
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ret = self.data[self.offset : self.offset + i]
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self.offset += i
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else:
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raise IndexError
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return ret
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def remaining_count(self) -> int:
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return len(self.data) - self.offset
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def read_bitcoin_varint(r: BytearrayReader) -> int:
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prefix = r.get()
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if prefix < 253:
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n = prefix
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elif prefix == 253:
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n = r.get()
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n += r.get() << 8
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elif prefix == 254:
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n = r.get()
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n += r.get() << 8
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n += r.get() << 16
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n += r.get() << 24
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else:
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raise ValueError
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return n
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