netarch/gapstr.py

166 lines
4.1 KiB
Python
Executable File

#! /usr/bin/python
## 2008 Massive Blowout
"""Functions to treat a list as a string with gaps.
Lists should have only string and integer items.
"""
import __init__
import sys
class GapString:
def __init__(self, init=None, drop='?'):
self.contents = []
self.length = 0
self.drop = drop
if init:
self.append(init)
def __len__(self):
return self.length
def __repr__(self):
return '<GapString of length %d>' % self.length
def append(self, i):
self.contents.append(i)
if isinstance(i, int):
self.length += i
else:
self.length += len(i)
def __str__(self):
ret = []
for i in self.contents:
if isinstance(i, int):
ret.append(self.drop * i)
else:
ret.append(i)
return ''.join(ret)
def __iter__(self):
for i in self.contents:
if isinstance(i, int):
for j in range(i):
yield self.drop
else:
for c in i:
yield c
def hexdump(self, fd=sys.stdout):
offset = 0
d = __init__.HexDumper(fd)
for i in self.contents:
if isinstance(i, int):
for j in range(i):
d.dump_drop()
else:
for c in i:
d.dump_chr(c)
d.finish()
def extend(self, other):
self.contents += other.contents
self.length += other.length
def __getslice__(self, start, end):
end = min(self.length, end)
start = min(self.length, start)
new = self.__class__(drop=self.drop)
new.length = max(end - start, 0)
if new.length == 0:
new.contents = []
return new
new.contents = self.contents[:]
l = self.length - new.length - start
# Trim off the beginning
while start >= 0:
i = new.contents.pop(0)
if isinstance(i, int):
start -= i
if start < 0:
new.contents.insert(0, -start)
else:
start -= len(i)
if start < 0:
new.contents.insert(0, i[start:])
# Trim off the end
while l >= 0:
i = new.contents.pop()
if isinstance(i, int):
l -= i
if l < 0:
new.contents.append(-l)
else:
l -= len(i)
if l < 0:
new.contents.append(i[:-l])
return new
def __getitem__(self, idx):
# XXX: speed up
return str(self)[idx]
def __add__(self, other):
if isinstance(other, str):
self.append(other)
else:
new = self.__class__(drop=self.drop)
new.extend(self)
new.extend(other)
return new
def __xor__(self, mask):
if isinstance(mask, int):
mask = [mask]
if isinstance(mask, str) or isinstance(mask, GapString):
mask = [ord(c) for c in mask]
masklen = len(mask)
new = self.__class__(drop=self.drop)
for i in self.contents:
if isinstance(i, int):
new.append(i)
else:
r = []
offset = len(new) % masklen
for c in i:
o = ord(c)
r.append(chr(o ^ mask[offset]))
offset = (offset + 1) % masklen
new.append(''.join(r))
return new
if __name__ == '__main__':
gs = GapString()
gs.append('hi')
assert str(gs) == 'hi'
assert str(gs[:40]) == 'hi'
gs.append(3)
assert str(gs) == 'hi???'
assert str(gs[:40]) == 'hi???'
assert str(gs[:3]) == 'hi?'
assert str(gs[-4:]) == 'i???'
assert str(gs + gs) == 'hi???hi???'
assert str(gs ^ 1) == 'ih???'
gs = GapString()
gs.append('123456789A')
assert str(gs[:4]) == '1234'
assert len(gs[:4]) == 4
assert len(gs[6:]) == 4
assert str(gs[:0]) == ''