diff options
Diffstat (limited to 'Demo')
| -rwxr-xr-x | Demo/classes/bitvec.py | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/Demo/classes/bitvec.py b/Demo/classes/bitvec.py new file mode 100755 index 0000000..40cd13f --- /dev/null +++ b/Demo/classes/bitvec.py @@ -0,0 +1,341 @@ +# +# 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 + +error = 'bitvec.error' + + +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 'FATAL', '(param, l) = ' + `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 lenght 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)' + + return self + + + def _init(self, data, len): + self._data = data + self._len = len + return self + + + def append(self, item): + #_check_value(item) + #self[self._len:self._len] = [item] + self[self._len:self._len] = \ + BitVec()._init(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()._init(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()._init(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' + `self._data, self._len` + + def __cmp__(self, other, *rest): + #rprt(`self`+'.__cmp__'+`(other, ) + rest`+'\n') + 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_lenght = 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(`self`+'.__len__()\n') + return self._len + + def __getitem__(self, key): + #rprt(`self`+'.__getitem__('+`key`+')\n') + key = _check_key(self._len, key) + return self._data & (1L << key) != 0 + + def __setitem__(self, key, value): + #rprt(`self`+'.__setitem__'+`key, value`+'\n') + 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(`self`+'.__delitem__('+`key`+')\n') + 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(`self`+'.__getslice__'+`i, j`+'\n') + i, j = _check_slice(self._len, i, j) + if i >= j: + return BitVec()._init(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()._init(ndata, nlength) + + def __setslice__(self, i, j, sequence, *rest): + #rprt(`self`+'.__setslice__'+`(i, j, sequence) + rest`+'\n') + 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(`self`+'.__delslice__'+`i, j`+'\n') + 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(`self`+'.__add__('+`other`+')\n') + retval = self.copy() + retval[self._len:self._len] = other + return retval + + def __mul__(self, multiplier): + #rprt(`self`+'.__mul__('+`multiplier`+')\n') + if type(multiplier) != type(0): + raise TypeError, 'sequence subscript not int' + if multiplier <= 0: + return BitVec()._init(0L, 0) + elif multiplier == 1: + return self.copy() + #handle special cases all 0 or all 1... + if self._data == 0L: + return BitVec()._init(0L, self._len * multiplier) + elif (~self)._data == 0L: + return ~BitVec()._init(0L, self._len * multiplier) + #otherwise el cheapo again... + retval = BitVec()._init(0L, 0) + while multiplier: + retval, multiplier = retval + self, multiplier - 1 + return retval + + def __and__(self, otherseq, *rest): + #rprt(`self`+'.__and__'+`(otherseq, ) + rest`+'\n') + if type(otherseq) != type(self): + otherseq = apply(bitvec, (otherseq, ) + rest) + #sequence is now of our own type + return BitVec()._init(self._data & otherseq._data, \ + min(self._len, otherseq._len)) + + + def __xor__(self, otherseq, *rest): + #rprt(`self`+'.__xor__'+`(otherseq, ) + rest`+'\n') + if type(otherseq) != type(self): + otherseq = apply(bitvec, (otherseq, ) + rest) + #sequence is now of our own type + return BitVec()._init(self._data ^ otherseq._data, \ + max(self._len, otherseq._len)) + + + def __or__(self, otherseq, *rest): + #rprt(`self`+'.__or__'+`(otherseq, ) + rest`+'\n') + if type(otherseq) != type(self): + otherseq = apply(bitvec, (otherseq, ) + rest) + #sequence is now of our own type + return BitVec()._init(self._data | otherseq._data, \ + max(self._len, otherseq._len)) + + + def __invert__(self): + #rprt(`self`+'.__invert__()\n') + return BitVec()._init(~self._data & ((1L << self._len) - 1), \ + self._len) + + def __coerce__(self, otherseq, *rest): + #needed for *some* of the arithmetic operations + #rprt(`self`+'.__coerce__'+`(otherseq, ) + rest`+'\n') + 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) + + +def bitvec(params): + return apply(BitVec().init, params) |