mirror of
https://github.com/python/cpython.git
synced 2025-11-04 07:31:38 +00:00
9c6bd77e39
svn+ssh://pythondev@svn.python.org/python/trunk ........ r78779 | benjamin.peterson | 2010-03-07 20:11:06 -0600 (Sun, 07 Mar 2010) | 1 line remove svn:executable from scripts without a shebang line ........
322 lines
9.8 KiB
Python
322 lines
9.8 KiB
Python
#
|
|
# this is a rather strict implementation of a bit vector class
|
|
# it is accessed the same way as an array of python-ints, except
|
|
# the value must be 0 or 1
|
|
#
|
|
|
|
import sys; rprt = sys.stderr.write #for debugging
|
|
|
|
class error(Exception):
|
|
pass
|
|
|
|
|
|
def _check_value(value):
|
|
if type(value) != type(0) or not 0 <= value < 2:
|
|
raise error('bitvec() items must have int value 0 or 1')
|
|
|
|
|
|
import math
|
|
|
|
def _compute_len(param):
|
|
mant, l = math.frexp(float(param))
|
|
bitmask = 1 << l
|
|
if bitmask <= param:
|
|
raise ValueError('(param, l) = %r' % ((param, l),))
|
|
while l:
|
|
bitmask = bitmask >> 1
|
|
if param & bitmask:
|
|
break
|
|
l = l - 1
|
|
return l
|
|
|
|
|
|
def _check_key(len, key):
|
|
if type(key) != type(0):
|
|
raise TypeError('sequence subscript not int')
|
|
if key < 0:
|
|
key = key + len
|
|
if not 0 <= key < len:
|
|
raise IndexError('list index out of range')
|
|
return key
|
|
|
|
def _check_slice(len, i, j):
|
|
#the type is ok, Python already checked that
|
|
i, j = max(i, 0), min(len, j)
|
|
if i > j:
|
|
i = j
|
|
return i, j
|
|
|
|
|
|
class BitVec:
|
|
|
|
def __init__(self, *params):
|
|
self._data = 0
|
|
self._len = 0
|
|
if not len(params):
|
|
pass
|
|
elif len(params) == 1:
|
|
param, = params
|
|
if type(param) == type([]):
|
|
value = 0
|
|
bit_mask = 1
|
|
for item in param:
|
|
# strict check
|
|
#_check_value(item)
|
|
if item:
|
|
value = value | bit_mask
|
|
bit_mask = bit_mask << 1
|
|
self._data = value
|
|
self._len = len(param)
|
|
elif type(param) == type(0):
|
|
if param < 0:
|
|
raise error('bitvec() can\'t handle negative longs')
|
|
self._data = param
|
|
self._len = _compute_len(param)
|
|
else:
|
|
raise error('bitvec() requires array or long parameter')
|
|
elif len(params) == 2:
|
|
param, length = params
|
|
if type(param) == type(0):
|
|
if param < 0:
|
|
raise error('can\'t handle negative longs')
|
|
self._data = param
|
|
if type(length) != type(0):
|
|
raise error('bitvec()\'s 2nd parameter must be int')
|
|
computed_length = _compute_len(param)
|
|
if computed_length > length:
|
|
print('warning: bitvec() value is longer than the length indicates, truncating value')
|
|
self._data = self._data & \
|
|
((1 << length) - 1)
|
|
self._len = length
|
|
else:
|
|
raise error('bitvec() requires array or long parameter')
|
|
else:
|
|
raise error('bitvec() requires 0 -- 2 parameter(s)')
|
|
|
|
|
|
def append(self, item):
|
|
#_check_value(item)
|
|
#self[self._len:self._len] = [item]
|
|
self[self._len:self._len] = \
|
|
BitVec(int(not not item), 1)
|
|
|
|
|
|
def count(self, value):
|
|
#_check_value(value)
|
|
if value:
|
|
data = self._data
|
|
else:
|
|
data = (~self)._data
|
|
count = 0
|
|
while data:
|
|
data, count = data >> 1, count + (data & 1 != 0)
|
|
return count
|
|
|
|
|
|
def index(self, value):
|
|
#_check_value(value):
|
|
if value:
|
|
data = self._data
|
|
else:
|
|
data = (~self)._data
|
|
index = 0
|
|
if not data:
|
|
raise ValueError('list.index(x): x not in list')
|
|
while not (data & 1):
|
|
data, index = data >> 1, index + 1
|
|
return index
|
|
|
|
|
|
def insert(self, index, item):
|
|
#_check_value(item)
|
|
#self[index:index] = [item]
|
|
self[index:index] = BitVec(int(not not item), 1)
|
|
|
|
|
|
def remove(self, value):
|
|
del self[self.index(value)]
|
|
|
|
|
|
def reverse(self):
|
|
#ouch, this one is expensive!
|
|
#for i in self._len>>1: self[i], self[l-i] = self[l-i], self[i]
|
|
data, result = self._data, 0
|
|
for i in range(self._len):
|
|
if not data:
|
|
result = result << (self._len - i)
|
|
break
|
|
result, data = (result << 1) | (data & 1), data >> 1
|
|
self._data = result
|
|
|
|
|
|
def sort(self):
|
|
c = self.count(1)
|
|
self._data = ((1 << c) - 1) << (self._len - c)
|
|
|
|
|
|
def copy(self):
|
|
return BitVec(self._data, self._len)
|
|
|
|
|
|
def seq(self):
|
|
result = []
|
|
for i in self:
|
|
result.append(i)
|
|
return result
|
|
|
|
|
|
def __repr__(self):
|
|
##rprt('<bitvec class instance object>.' + '__repr__()\n')
|
|
return 'bitvec(%r, %r)' % (self._data, self._len)
|
|
|
|
def __cmp__(self, other, *rest):
|
|
#rprt('%r.__cmp__%r\n' % (self, (other,) + rest))
|
|
if type(other) != type(self):
|
|
other = bitvec(other, *rest)
|
|
#expensive solution... recursive binary, with slicing
|
|
length = self._len
|
|
if length == 0 or other._len == 0:
|
|
return cmp(length, other._len)
|
|
if length != other._len:
|
|
min_length = min(length, other._len)
|
|
return cmp(self[:min_length], other[:min_length]) or \
|
|
cmp(self[min_length:], other[min_length:])
|
|
#the lengths are the same now...
|
|
if self._data == other._data:
|
|
return 0
|
|
if length == 1:
|
|
return cmp(self[0], other[0])
|
|
else:
|
|
length = length >> 1
|
|
return cmp(self[:length], other[:length]) or \
|
|
cmp(self[length:], other[length:])
|
|
|
|
|
|
def __len__(self):
|
|
#rprt('%r.__len__()\n' % (self,))
|
|
return self._len
|
|
|
|
def __getitem__(self, key):
|
|
#rprt('%r.__getitem__(%r)\n' % (self, key))
|
|
key = _check_key(self._len, key)
|
|
return self._data & (1 << key) != 0
|
|
|
|
def __setitem__(self, key, value):
|
|
#rprt('%r.__setitem__(%r, %r)\n' % (self, key, value))
|
|
key = _check_key(self._len, key)
|
|
#_check_value(value)
|
|
if value:
|
|
self._data = self._data | (1 << key)
|
|
else:
|
|
self._data = self._data & ~(1 << key)
|
|
|
|
def __delitem__(self, key):
|
|
#rprt('%r.__delitem__(%r)\n' % (self, key))
|
|
key = _check_key(self._len, key)
|
|
#el cheapo solution...
|
|
self._data = self[:key]._data | self[key+1:]._data >> key
|
|
self._len = self._len - 1
|
|
|
|
def __getslice__(self, i, j):
|
|
#rprt('%r.__getslice__(%r, %r)\n' % (self, i, j))
|
|
i, j = _check_slice(self._len, i, j)
|
|
if i >= j:
|
|
return BitVec(0, 0)
|
|
if i:
|
|
ndata = self._data >> i
|
|
else:
|
|
ndata = self._data
|
|
nlength = j - i
|
|
if j != self._len:
|
|
#we'll have to invent faster variants here
|
|
#e.g. mod_2exp
|
|
ndata = ndata & ((1 << nlength) - 1)
|
|
return BitVec(ndata, nlength)
|
|
|
|
def __setslice__(self, i, j, sequence, *rest):
|
|
#rprt('%s.__setslice__%r\n' % (self, (i, j, sequence) + rest))
|
|
i, j = _check_slice(self._len, i, j)
|
|
if type(sequence) != type(self):
|
|
sequence = bitvec(sequence, *rest)
|
|
#sequence is now of our own type
|
|
ls_part = self[:i]
|
|
ms_part = self[j:]
|
|
self._data = ls_part._data | \
|
|
((sequence._data | \
|
|
(ms_part._data << sequence._len)) << ls_part._len)
|
|
self._len = self._len - j + i + sequence._len
|
|
|
|
def __delslice__(self, i, j):
|
|
#rprt('%r.__delslice__(%r, %r)\n' % (self, i, j))
|
|
i, j = _check_slice(self._len, i, j)
|
|
if i == 0 and j == self._len:
|
|
self._data, self._len = 0, 0
|
|
elif i < j:
|
|
self._data = self[:i]._data | (self[j:]._data >> i)
|
|
self._len = self._len - j + i
|
|
|
|
def __add__(self, other):
|
|
#rprt('%r.__add__(%r)\n' % (self, other))
|
|
retval = self.copy()
|
|
retval[self._len:self._len] = other
|
|
return retval
|
|
|
|
def __mul__(self, multiplier):
|
|
#rprt('%r.__mul__(%r)\n' % (self, multiplier))
|
|
if type(multiplier) != type(0):
|
|
raise TypeError('sequence subscript not int')
|
|
if multiplier <= 0:
|
|
return BitVec(0, 0)
|
|
elif multiplier == 1:
|
|
return self.copy()
|
|
#handle special cases all 0 or all 1...
|
|
if self._data == 0:
|
|
return BitVec(0, self._len * multiplier)
|
|
elif (~self)._data == 0:
|
|
return ~BitVec(0, self._len * multiplier)
|
|
#otherwise el cheapo again...
|
|
retval = BitVec(0, 0)
|
|
while multiplier:
|
|
retval, multiplier = retval + self, multiplier - 1
|
|
return retval
|
|
|
|
def __and__(self, otherseq, *rest):
|
|
#rprt('%r.__and__%r\n' % (self, (otherseq,) + rest))
|
|
if type(otherseq) != type(self):
|
|
otherseq = bitvec(otherseq, *rest)
|
|
#sequence is now of our own type
|
|
return BitVec(self._data & otherseq._data, \
|
|
min(self._len, otherseq._len))
|
|
|
|
|
|
def __xor__(self, otherseq, *rest):
|
|
#rprt('%r.__xor__%r\n' % (self, (otherseq,) + rest))
|
|
if type(otherseq) != type(self):
|
|
otherseq = bitvec(otherseq, *rest)
|
|
#sequence is now of our own type
|
|
return BitVec(self._data ^ otherseq._data, \
|
|
max(self._len, otherseq._len))
|
|
|
|
|
|
def __or__(self, otherseq, *rest):
|
|
#rprt('%r.__or__%r\n' % (self, (otherseq,) + rest))
|
|
if type(otherseq) != type(self):
|
|
otherseq = bitvec(otherseq, *rest)
|
|
#sequence is now of our own type
|
|
return BitVec(self._data | otherseq._data, \
|
|
max(self._len, otherseq._len))
|
|
|
|
|
|
def __invert__(self):
|
|
#rprt('%r.__invert__()\n' % (self,))
|
|
return BitVec(~self._data & ((1 << self._len) - 1), \
|
|
self._len)
|
|
|
|
def __int__(self):
|
|
return int(self._data)
|
|
|
|
def __float__(self):
|
|
return float(self._data)
|
|
|
|
|
|
bitvec = BitVec
|