73 lines
2.3 KiB
Python
73 lines
2.3 KiB
Python
# Copyright (c) Kuba Szczodrzyński 2022-05-27.
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from typing import Dict, List, Tuple
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from models import Opcode
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from tools.util.intbin import intto8, letoint, sinttole32
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def bindiff(
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data1: bytes, data2: bytes, width: int = 1, single: bool = False
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) -> Dict[int, Tuple[bytes, bytes]]:
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out: Dict[int, Tuple[bytes, bytes]] = {}
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offs = -1
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diff1 = b""
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diff2 = b""
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for i in range(0, len(data1), width):
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block1 = data1[i : i + width]
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block2 = data2[i : i + width]
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if block1 == block2:
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# blocks are equal again
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if offs != -1:
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# store and reset current difference
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out[offs] = (diff1, diff2)
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offs = -1
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diff1 = b""
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diff2 = b""
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continue
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# blocks still differ
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if single:
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# single block per difference, so just store it
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out[i] = (block1, block2)
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else:
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if offs == -1:
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# difference starts here
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offs = i
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diff1 += block1
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diff2 += block2
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return out
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def binpatch32(block1: bytes, block2: bytes, bladdr: int = 0) -> bytes:
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# compare blocks:
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# - in 4 byte (32 bit) chunks
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# - report a single chunk in each difference
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diffs = bindiff(block1, block2, width=4, single=True)
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binpatch: Dict[int, List[int]] = {}
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# gather all repeating differences (i.e. memory offsets for OTA1/OTA2)
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for offs, diff in diffs.items():
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(diff1, diff2) = diff
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diff1 = letoint(diff1)
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diff2 = letoint(diff2)
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diff = diff2 - diff1
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if diff in binpatch:
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# difference already in this binpatch, add the offset
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binpatch[diff].append(offs)
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else:
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# a new difference value
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binpatch[diff] = [offs]
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# print(f"Block at 0x{bladdr:x}+{offs:02x} -> {diff1:08x} - {diff2:08x} = {diff2-diff1:x}")
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# print(f"Block at 0x{bladdr:x}: {len(binpatch)} difference(s) at {sum(len(v) for v in binpatch.values())} offsets")
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# write binary patches
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out = b""
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for diff, offs in binpatch.items():
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out += intto8(Opcode.DIFF32.value)
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out += intto8(len(offs) + 4)
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out += sinttole32(diff)
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out += bytes(offs)
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return out
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