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Adding support for converting swarm hash to STOP and toggling disasse… #17

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Adding support for converting swarm hash to STOP and toggling disasse… #17

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18 changes: 17 additions & 1 deletion pyevmasm/__main__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,8 @@ def main():
group_action.add_argument('-t', '--print-opcode-table', action='store_true', help='List supported EVM opcodes')
parser.add_argument('-bi', '--binary-input', action='store_true', help='Binary input mode (-d only)')
parser.add_argument('-bo', '--binary-output', action='store_true', help='Binary output mode (-a only)')
parser.add_argument('-N', '--no-offsets', action='store_true', help='Do not print the file offset of the current instruction (-d only)')
parser.add_argument('-S', '--no-swarmhash', action='store_true', help='Convert swarm hash to STOP opcodes')
parser.add_argument('-i', '--input', nargs='?', default=sys.stdin, type=argparse.FileType('r'),
help='Input file, default=stdin')
parser.add_argument('-o', '--output', nargs='?', default=sys.stdout, type=argparse.FileType('w'),
Expand Down Expand Up @@ -65,10 +67,24 @@ def main():
if buf_set <= hex_set: # subset
buf = binascii.unhexlify(buf)

# replace all swarm hashes with \x00
if args.no_swarmhash:
while True: #detect multiple swarm hashes, about 700 contracts do
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We can simplify it by using re.sub (regex replace). Example:

In [9]: re.sub(b'\x12..', b'\x00'*4, b'\x1234 abc \x1233 \x1234')
Out[9]: b'\x00\x00\x00\x00 abc \x00\x00\x00\x00 \x00\x00\x00\x00'

So here it should probably be (pls check this):

buf = re.sub(b'\xa1ebzzr0X .{34}', b'\x00'*43, buf)

if '\xa1ebzzr0X ' in buf:
# replace the swarm hash with stops
offset = buf.find('\xa1ebzzr0X ')
buf = buf[:offset] + b'\x00' * 43 + buf[offset+43:]
else:
break

insns = list(disassemble_all(buf))
for i in insns:
args.output.write("%08x: %s\n" % (i.pc, str(i)))
if args.no_offsets:
args.output.write("%s\n" % (str(i),))
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the (,) is redundant so it could be % str(i) but I understand it might be better to leave it s it is.
We could also use "{}\n".format(i)

else:
args.output.write("%08x: %s\n" % (i.pc, str(i)))


print("done")
if __name__ == "__main__":
main()