mirror of
https://github.com/cea-sec/miasm
synced 2026-06-21 13:48:18 +00:00
Fabrice Desclaux
107 lines
2.7 KiB
Python
107 lines
2.7 KiB
Python
from array import array
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import struct
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from sys import maxsize
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from future.utils import PY3
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if PY3:
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def array_frombytes(arr, value):
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return arr.frombytes(value)
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def array_tobytes(arr):
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return arr.tobytes()
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else:
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def array_frombytes(arr, value):
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return arr.fromstring(value)
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def array_tobytes(arr):
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return arr.tostring()
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class StrPatchwork(object):
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def __init__(self, s=b"", paddingbyte=b"\x00"):
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s_raw = bytes(s)
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val = array("B")
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array_frombytes(val, s_raw)
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self.s = val
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# cache s to avoid rebuilding str after each find
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self.s_cache = s_raw
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self.paddingbyte = paddingbyte
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def __bytes__(self):
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return array_tobytes(self.s)
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def __str__(self):
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if PY3:
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return repr(self)
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return self.__bytes__()
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def __getitem__(self, item):
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s = self.s
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if isinstance(item, slice):
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end = item.stop
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l = len(s)
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if (end is not None and l < end) and end != maxsize:
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# XXX hack [x:] give 2GB limit
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# This is inefficient but avoids complicated maths if step is
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# not 1
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s = s[:]
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tmp = array("B")
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array_frombytes(tmp, self.paddingbyte * (end - l))
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s.extend(tmp)
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r = s[item]
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return array_tobytes(r)
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else:
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if item > len(s):
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return self.paddingbyte
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else:
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return struct.pack("B", s[item])
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def __setitem__(self, item, val):
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if val is None:
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return
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val_array = array("B")
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array_frombytes(val_array, bytes(val))
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if type(item) is not slice:
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item = slice(item, item + len(val_array))
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end = item.stop
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l = len(self.s)
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if l < end:
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tmp = array("B")
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array_frombytes(tmp, self.paddingbyte * (end - l))
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self.s.extend(tmp)
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self.s[item] = val_array
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self.s_cache = None
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def __repr__(self):
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return "<Patchwork %r>" % array_tobytes(self.s)
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def __len__(self):
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return len(self.s)
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def __contains__(self, val):
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return val in bytes(self)
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def __iadd__(self, other):
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tmp = array("B")
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array_frombytes(tmp, bytes(other))
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self.s.extend(tmp)
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return self
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def find(self, pattern, start=0, end=None):
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if not self.s_cache:
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self.s_cache = array_tobytes(self.s)
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return self.s_cache.find(pattern, start, end)
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def rfind(self, pattern, start=0, end=None):
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if not self.s_cache:
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self.s_cache = array_tobytes(self.s)
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return self.s_cache.rfind(pattern, start, end)
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