mirror of https://github.com/dirtbags/netarch.git
143 lines
3.5 KiB
Python
Executable File
143 lines
3.5 KiB
Python
Executable File
#! /usr/bin/python
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"""Functions to treat a list as a string with gaps.
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Lists should have only string and integer items.
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"""
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import __init__
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import sys
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class GapString:
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def __init__(self, drop='?'):
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self.contents = []
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self.length = 0
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self.drop = drop
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def __len__(self):
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return self.length
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def __repr__(self):
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return '<GapString of length %d>' % self.length
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def append(self, i):
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self.contents.append(i)
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if isinstance(i, int):
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self.length += i
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else:
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self.length += len(i)
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def __str__(self):
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ret = []
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for i in self.contents:
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if isinstance(i, int):
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ret.append(self.drop * i)
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else:
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ret.append(i)
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return ''.join(ret)
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def hexdump(self, fd=sys.stdout):
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offset = 0
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d = __init__.HexDumper(fd)
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for i in self.contents:
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if isinstance(i, int):
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for j in range(i):
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d.dump_drop()
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else:
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for c in i:
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d.dump_chr(c)
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d.finish()
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def extend(self, other):
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self.contents += other.contents
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self.length += other.length
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def __getslice__(self, start, end):
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end = min(self.length, end)
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start = min(self.length, start)
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new = self.__class__(self.drop)
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new.contents = self.contents[:]
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new.length = end - start
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if new.length == 0:
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return new
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l = self.length - new.length - start
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# Trim off the beginning
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while start >= 0:
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i = new.contents.pop(0)
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if isinstance(i, int):
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start -= i
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if start < 0:
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new.contents.insert(0, -start)
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else:
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start -= len(i)
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if start < 0:
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new.contents.insert(0, i[start:])
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# Trim off the end
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while l >= 0:
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i = new.contents.pop()
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if isinstance(i, int):
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l -= i
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if l < 0:
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new.contents.append(-l)
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else:
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l -= len(i)
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if l < 0:
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new.contents.append(i[:-l])
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return new
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def __add__(self, other):
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if isinstance(other, str):
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self.append(other)
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else:
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new = self.__class__(self.drop)
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new.extend(self)
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new.extend(other)
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return new
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def __xor__(self, mask):
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if isinstance(mask, int):
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mask = [mask]
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masklen = len(mask)
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new = self.__class__(self.drop)
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for i in self.contents:
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if isinstance(i, int):
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new.append(i)
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else:
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r = []
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offset = len(new) % masklen
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for c in i:
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o = ord(c)
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r.append(chr(o ^ mask[offset]))
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offset = (offset + 1) % masklen
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new.append(''.join(r))
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return new
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if __name__ == '__main__':
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gs = GapString()
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gs.append('hi')
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assert str(gs) == 'hi'
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assert str(gs[:40]) == 'hi'
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gs.append(3)
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assert str(gs) == 'hi???'
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assert str(gs[:40]) == 'hi???'
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assert str(gs[:3]) == 'hi?'
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assert str(gs[-4:]) == 'i???'
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assert str(gs + gs) == 'hi???hi???'
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assert str(gs ^ 1) == 'ih???'
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gs = GapString()
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gs.append('123456789A')
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assert str(gs[:4]) == '1234'
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assert len(gs[:4]) == 4
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assert len(gs[6:]) == 4
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