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96 lines
3.0 KiB
96 lines
3.0 KiB
import binascii
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import varint
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class ExtraParser(object):
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TX_EXTRA_TAG_PADDING = 0x00
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TX_EXTRA_TAG_PUBKEY = 0x01
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TX_EXTRA_TAG_EXTRA_NONCE = 0x02
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TX_EXTRA_TAG_ADDITIONAL_PUBKEYS = 0x04
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KNOWN_TAGS = (
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TX_EXTRA_TAG_PADDING,
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TX_EXTRA_TAG_PUBKEY,
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TX_EXTRA_TAG_EXTRA_NONCE,
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TX_EXTRA_TAG_ADDITIONAL_PUBKEYS,
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)
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def __init__(self, extra):
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if isinstance(extra, str):
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extra = binascii.unhexlify(extra)
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if isinstance(extra, bytes):
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extra = list(extra)
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self.extra = extra
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def parse(self):
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self.data = {}
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self.offset = 0
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self._parse(self.extra)
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return self.data
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def _strip_padding(self, extra):
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while extra and extra[0] == self.TX_EXTRA_TAG_PADDING:
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extra = extra[1:]
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self.offset += 1
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return extra
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def _pop_pubkey(self, extra):
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key = bytes(bytearray(extra[:32])) # bytearray() is for py2 compatibility
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if len(key) < 32:
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raise ValueError(
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"offset {:d}: only {:d} bytes of key data, expected 32".format(
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self.offset, len(key)
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)
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)
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if "pubkeys" in self.data:
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self.data["pubkeys"].append(key)
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else:
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self.data["pubkeys"] = [key]
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extra = extra[32:]
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self.offset += 32
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return extra
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def _extract_pubkey(self, extra):
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if extra:
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if extra[0] == self.TX_EXTRA_TAG_PUBKEY:
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extra = extra[1:]
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self.offset += 1
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extra = self._pop_pubkey(extra)
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elif extra[0] == self.TX_EXTRA_TAG_ADDITIONAL_PUBKEYS:
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extra = extra[1:]
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self.offset += 1
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keycount = varint.decode_bytes(bytearray(extra))
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valen = len(varint.encode(keycount))
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extra = extra[valen:]
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self.offset += valen
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for i in range(keycount):
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extra = self._pop_pubkey(extra)
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return extra
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def _extract_nonce(self, extra):
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if extra and extra[0] == self.TX_EXTRA_TAG_EXTRA_NONCE:
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noncelen = extra[1]
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extra = extra[2:]
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self.offset += 2
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if noncelen > len(extra):
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raise ValueError(
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"offset {:d}: extra nonce exceeds field size".format(self.offset)
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)
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nonce = bytearray(extra[:noncelen])
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if "nonces" in self.data:
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self.data["nonces"].append(nonce)
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else:
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self.data["nonces"] = [nonce]
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extra = extra[noncelen:]
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self.offset += noncelen
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return extra
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def _parse(self, extra):
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while extra:
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if extra[0] not in self.KNOWN_TAGS:
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raise ValueError(
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"offset {:d}: unknown tag 0x{:x}".format(self.offset, extra[0])
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)
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extra = self._strip_padding(extra)
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extra = self._extract_pubkey(extra)
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extra = self._extract_nonce(extra)
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