forked from LBRYCommunity/lbry-sdk
84 lines
3.2 KiB
Python
84 lines
3.2 KiB
Python
import struct
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from typing import Optional
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from binascii import hexlify, unhexlify
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from torba.baseheader import BaseHeaders
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from torba.util import ArithUint256
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from torba.hash import sha512, double_sha256, ripemd160
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class Headers(BaseHeaders):
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header_size = 112
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chunk_size = 10**16
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max_target = 0x0000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
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genesis_hash = b'9c89283ba0f3227f6c03b70216b9f665f0118d5e0fa729cedf4fb34d6a34f463'
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target_timespan = 150
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@property
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def claim_trie_root(self):
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return self[self.height]['claim_trie_root']
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@staticmethod
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def serialize(header):
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return b''.join([
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struct.pack('<I', header['version']),
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unhexlify(header['prev_block_hash'])[::-1],
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unhexlify(header['merkle_root'])[::-1],
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unhexlify(header['claim_trie_root'])[::-1],
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struct.pack('<III', header['timestamp'], header['bits'], header['nonce'])
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])
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@staticmethod
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def deserialize(height, header):
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version, = struct.unpack('<I', header[:4])
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timestamp, bits, nonce = struct.unpack('<III', header[100:112])
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return {
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'version': version,
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'prev_block_hash': hexlify(header[4:36][::-1]),
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'merkle_root': hexlify(header[36:68][::-1]),
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'claim_trie_root': hexlify(header[68:100][::-1]),
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'timestamp': timestamp,
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'bits': bits,
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'nonce': nonce,
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'block_height': height,
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}
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def get_next_block_target(self, max_target: ArithUint256, previous: Optional[dict],
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current: Optional[dict]) -> ArithUint256:
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# https://github.com/lbryio/lbrycrd/blob/master/src/lbry.cpp
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if previous is None and current is None:
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return max_target
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if previous is None:
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previous = current
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actual_timespan = current['timestamp'] - previous['timestamp']
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modulated_timespan = self.target_timespan + int((actual_timespan - self.target_timespan) / 8)
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minimum_timespan = self.target_timespan - int(self.target_timespan / 8) # 150 - 18 = 132
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maximum_timespan = self.target_timespan + int(self.target_timespan / 2) # 150 + 75 = 225
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clamped_timespan = max(minimum_timespan, min(modulated_timespan, maximum_timespan))
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target = ArithUint256.from_compact(current['bits'])
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new_target = min(max_target, (target * clamped_timespan) / self.target_timespan)
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return new_target
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@classmethod
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def get_proof_of_work(cls, header_hash: bytes):
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return super().get_proof_of_work(
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cls.header_hash_to_pow_hash(header_hash)
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)
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@staticmethod
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def header_hash_to_pow_hash(header_hash: bytes):
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header_hash_bytes = unhexlify(header_hash)[::-1]
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h = sha512(header_hash_bytes)
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pow_hash = double_sha256(
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ripemd160(h[:len(h) // 2]) +
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ripemd160(h[len(h) // 2:])
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)
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return hexlify(pow_hash[::-1])
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class UnvalidatedHeaders(Headers):
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validate_difficulty = False
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max_target = 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
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genesis_hash = b'6e3fcf1299d4ec5d79c3a4c91d624a4acf9e2e173d95a1a0504f677669687556'
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