| # | |
| # 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 = 1L << l | |
| if bitmask <= param: | |
| raise RuntimeError('(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 = 0L | |
| self._len = 0 | |
| if not len(params): | |
| pass | |
| elif len(params) == 1: | |
| param, = params | |
| if type(param) == type([]): | |
| value = 0L | |
| bit_mask = 1L | |
| 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(0L): | |
| 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(0L): | |
| 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 & \ | |
| ((1L << 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(long(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(long(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, 0L | |
| 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 = ((1L << 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 = apply(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 & (1L << 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 | (1L << key) | |
| else: | |
| self._data = self._data & ~(1L << 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(0L, 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 & ((1L << 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 = apply(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 = 0L, 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(0L, 0) | |
| elif multiplier == 1: | |
| return self.copy() | |
| #handle special cases all 0 or all 1... | |
| if self._data == 0L: | |
| return BitVec(0L, self._len * multiplier) | |
| elif (~self)._data == 0L: | |
| return ~BitVec(0L, self._len * multiplier) | |
| #otherwise el cheapo again... | |
| retval = BitVec(0L, 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 = apply(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 = apply(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 = apply(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 & ((1L << self._len) - 1), \ | |
| self._len) | |
| def __coerce__(self, otherseq, *rest): | |
| #needed for *some* of the arithmetic operations | |
| #rprt('%r.__coerce__%r\n' % (self, (otherseq,) + rest)) | |
| if type(otherseq) != type(self): | |
| otherseq = apply(bitvec, (otherseq, ) + rest) | |
| return self, otherseq | |
| def __int__(self): | |
| return int(self._data) | |
| def __long__(self): | |
| return long(self._data) | |
| def __float__(self): | |
| return float(self._data) | |
| bitvec = BitVec |