35 lines
934 B
Python
35 lines
934 B
Python
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# sid_canonical.py
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from typing import List, Tuple
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# ---------------------------------------------------------------------
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# Canonical string encoder
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# ---------------------------------------------------------------------
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def encode_str(s: str) -> bytes:
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"""
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Encode a string deterministically as length-prefixed UTF-8 bytes.
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"""
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b = s.encode("utf-8")
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return len(b).to_bytes(4, "big") + b
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# ---------------------------------------------------------------------
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# Canonical key-value encoder
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# ---------------------------------------------------------------------
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def encode_kv_pairs(pairs: List[Tuple[str, str]]) -> bytes:
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"""
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Encode sorted key-value pairs deterministically.
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Format:
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[num_pairs][key_len][key_bytes][value_len][value_bytes]...
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"""
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out = len(pairs).to_bytes(4, "big")
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for k, v in pairs:
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out += encode_str(k)
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out += encode_str(v)
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return out
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