diff options
Diffstat (limited to 'lib/python2.7/_abcoll.py')
-rw-r--r-- | lib/python2.7/_abcoll.py | 695 |
1 files changed, 695 insertions, 0 deletions
diff --git a/lib/python2.7/_abcoll.py b/lib/python2.7/_abcoll.py new file mode 100644 index 0000000..b643692 --- /dev/null +++ b/lib/python2.7/_abcoll.py @@ -0,0 +1,695 @@ +# Copyright 2007 Google, Inc. All Rights Reserved. +# Licensed to PSF under a Contributor Agreement. + +"""Abstract Base Classes (ABCs) for collections, according to PEP 3119. + +DON'T USE THIS MODULE DIRECTLY! The classes here should be imported +via collections; they are defined here only to alleviate certain +bootstrapping issues. Unit tests are in test_collections. +""" + +from abc import ABCMeta, abstractmethod +import sys + +__all__ = ["Hashable", "Iterable", "Iterator", + "Sized", "Container", "Callable", + "Set", "MutableSet", + "Mapping", "MutableMapping", + "MappingView", "KeysView", "ItemsView", "ValuesView", + "Sequence", "MutableSequence", + ] + +### ONE-TRICK PONIES ### + +def _hasattr(C, attr): + try: + return any(attr in B.__dict__ for B in C.__mro__) + except AttributeError: + # Old-style class + return hasattr(C, attr) + + +class Hashable: + __metaclass__ = ABCMeta + + @abstractmethod + def __hash__(self): + return 0 + + @classmethod + def __subclasshook__(cls, C): + if cls is Hashable: + try: + for B in C.__mro__: + if "__hash__" in B.__dict__: + if B.__dict__["__hash__"]: + return True + break + except AttributeError: + # Old-style class + if getattr(C, "__hash__", None): + return True + return NotImplemented + + +class Iterable: + __metaclass__ = ABCMeta + + @abstractmethod + def __iter__(self): + while False: + yield None + + @classmethod + def __subclasshook__(cls, C): + if cls is Iterable: + if _hasattr(C, "__iter__"): + return True + return NotImplemented + +Iterable.register(str) + + +class Iterator(Iterable): + + @abstractmethod + def next(self): + 'Return the next item from the iterator. When exhausted, raise StopIteration' + raise StopIteration + + def __iter__(self): + return self + + @classmethod + def __subclasshook__(cls, C): + if cls is Iterator: + if _hasattr(C, "next") and _hasattr(C, "__iter__"): + return True + return NotImplemented + + +class Sized: + __metaclass__ = ABCMeta + + @abstractmethod + def __len__(self): + return 0 + + @classmethod + def __subclasshook__(cls, C): + if cls is Sized: + if _hasattr(C, "__len__"): + return True + return NotImplemented + + +class Container: + __metaclass__ = ABCMeta + + @abstractmethod + def __contains__(self, x): + return False + + @classmethod + def __subclasshook__(cls, C): + if cls is Container: + if _hasattr(C, "__contains__"): + return True + return NotImplemented + + +class Callable: + __metaclass__ = ABCMeta + + @abstractmethod + def __call__(self, *args, **kwds): + return False + + @classmethod + def __subclasshook__(cls, C): + if cls is Callable: + if _hasattr(C, "__call__"): + return True + return NotImplemented + + +### SETS ### + + +class Set(Sized, Iterable, Container): + """A set is a finite, iterable container. + + This class provides concrete generic implementations of all + methods except for __contains__, __iter__ and __len__. + + To override the comparisons (presumably for speed, as the + semantics are fixed), redefine __le__ and __ge__, + then the other operations will automatically follow suit. + """ + + def __le__(self, other): + if not isinstance(other, Set): + return NotImplemented + if len(self) > len(other): + return False + for elem in self: + if elem not in other: + return False + return True + + def __lt__(self, other): + if not isinstance(other, Set): + return NotImplemented + return len(self) < len(other) and self.__le__(other) + + def __gt__(self, other): + if not isinstance(other, Set): + return NotImplemented + return len(self) > len(other) and self.__ge__(other) + + def __ge__(self, other): + if not isinstance(other, Set): + return NotImplemented + if len(self) < len(other): + return False + for elem in other: + if elem not in self: + return False + return True + + def __eq__(self, other): + if not isinstance(other, Set): + return NotImplemented + return len(self) == len(other) and self.__le__(other) + + def __ne__(self, other): + return not (self == other) + + @classmethod + def _from_iterable(cls, it): + '''Construct an instance of the class from any iterable input. + + Must override this method if the class constructor signature + does not accept an iterable for an input. + ''' + return cls(it) + + def __and__(self, other): + if not isinstance(other, Iterable): + return NotImplemented + return self._from_iterable(value for value in other if value in self) + + __rand__ = __and__ + + def isdisjoint(self, other): + 'Return True if two sets have a null intersection.' + for value in other: + if value in self: + return False + return True + + def __or__(self, other): + if not isinstance(other, Iterable): + return NotImplemented + chain = (e for s in (self, other) for e in s) + return self._from_iterable(chain) + + __ror__ = __or__ + + def __sub__(self, other): + if not isinstance(other, Set): + if not isinstance(other, Iterable): + return NotImplemented + other = self._from_iterable(other) + return self._from_iterable(value for value in self + if value not in other) + + def __rsub__(self, other): + if not isinstance(other, Set): + if not isinstance(other, Iterable): + return NotImplemented + other = self._from_iterable(other) + return self._from_iterable(value for value in other + if value not in self) + + def __xor__(self, other): + if not isinstance(other, Set): + if not isinstance(other, Iterable): + return NotImplemented + other = self._from_iterable(other) + return (self - other) | (other - self) + + __rxor__ = __xor__ + + # Sets are not hashable by default, but subclasses can change this + __hash__ = None + + def _hash(self): + """Compute the hash value of a set. + + Note that we don't define __hash__: not all sets are hashable. + But if you define a hashable set type, its __hash__ should + call this function. + + This must be compatible __eq__. + + All sets ought to compare equal if they contain the same + elements, regardless of how they are implemented, and + regardless of the order of the elements; so there's not much + freedom for __eq__ or __hash__. We match the algorithm used + by the built-in frozenset type. + """ + MAX = sys.maxint + MASK = 2 * MAX + 1 + n = len(self) + h = 1927868237 * (n + 1) + h &= MASK + for x in self: + hx = hash(x) + h ^= (hx ^ (hx << 16) ^ 89869747) * 3644798167 + h &= MASK + h = h * 69069 + 907133923 + h &= MASK + if h > MAX: + h -= MASK + 1 + if h == -1: + h = 590923713 + return h + +Set.register(frozenset) + + +class MutableSet(Set): + """A mutable set is a finite, iterable container. + + This class provides concrete generic implementations of all + methods except for __contains__, __iter__, __len__, + add(), and discard(). + + To override the comparisons (presumably for speed, as the + semantics are fixed), all you have to do is redefine __le__ and + then the other operations will automatically follow suit. + """ + + @abstractmethod + def add(self, value): + """Add an element.""" + raise NotImplementedError + + @abstractmethod + def discard(self, value): + """Remove an element. Do not raise an exception if absent.""" + raise NotImplementedError + + def remove(self, value): + """Remove an element. If not a member, raise a KeyError.""" + if value not in self: + raise KeyError(value) + self.discard(value) + + def pop(self): + """Return the popped value. Raise KeyError if empty.""" + it = iter(self) + try: + value = next(it) + except StopIteration: + raise KeyError + self.discard(value) + return value + + def clear(self): + """This is slow (creates N new iterators!) but effective.""" + try: + while True: + self.pop() + except KeyError: + pass + + def __ior__(self, it): + for value in it: + self.add(value) + return self + + def __iand__(self, it): + for value in (self - it): + self.discard(value) + return self + + def __ixor__(self, it): + if it is self: + self.clear() + else: + if not isinstance(it, Set): + it = self._from_iterable(it) + for value in it: + if value in self: + self.discard(value) + else: + self.add(value) + return self + + def __isub__(self, it): + if it is self: + self.clear() + else: + for value in it: + self.discard(value) + return self + +MutableSet.register(set) + + +### MAPPINGS ### + + +class Mapping(Sized, Iterable, Container): + + """A Mapping is a generic container for associating key/value + pairs. + + This class provides concrete generic implementations of all + methods except for __getitem__, __iter__, and __len__. + + """ + + @abstractmethod + def __getitem__(self, key): + raise KeyError + + def get(self, key, default=None): + 'D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.' + try: + return self[key] + except KeyError: + return default + + def __contains__(self, key): + try: + self[key] + except KeyError: + return False + else: + return True + + def iterkeys(self): + 'D.iterkeys() -> an iterator over the keys of D' + return iter(self) + + def itervalues(self): + 'D.itervalues() -> an iterator over the values of D' + for key in self: + yield self[key] + + def iteritems(self): + 'D.iteritems() -> an iterator over the (key, value) items of D' + for key in self: + yield (key, self[key]) + + def keys(self): + "D.keys() -> list of D's keys" + return list(self) + + def items(self): + "D.items() -> list of D's (key, value) pairs, as 2-tuples" + return [(key, self[key]) for key in self] + + def values(self): + "D.values() -> list of D's values" + return [self[key] for key in self] + + # Mappings are not hashable by default, but subclasses can change this + __hash__ = None + + def __eq__(self, other): + if not isinstance(other, Mapping): + return NotImplemented + return dict(self.items()) == dict(other.items()) + + def __ne__(self, other): + return not (self == other) + +class MappingView(Sized): + + def __init__(self, mapping): + self._mapping = mapping + + def __len__(self): + return len(self._mapping) + + def __repr__(self): + return '{0.__class__.__name__}({0._mapping!r})'.format(self) + + +class KeysView(MappingView, Set): + + @classmethod + def _from_iterable(self, it): + return set(it) + + def __contains__(self, key): + return key in self._mapping + + def __iter__(self): + for key in self._mapping: + yield key + +KeysView.register(type({}.viewkeys())) + +class ItemsView(MappingView, Set): + + @classmethod + def _from_iterable(self, it): + return set(it) + + def __contains__(self, item): + key, value = item + try: + v = self._mapping[key] + except KeyError: + return False + else: + return v == value + + def __iter__(self): + for key in self._mapping: + yield (key, self._mapping[key]) + +ItemsView.register(type({}.viewitems())) + +class ValuesView(MappingView): + + def __contains__(self, value): + for key in self._mapping: + if value == self._mapping[key]: + return True + return False + + def __iter__(self): + for key in self._mapping: + yield self._mapping[key] + +ValuesView.register(type({}.viewvalues())) + +class MutableMapping(Mapping): + + """A MutableMapping is a generic container for associating + key/value pairs. + + This class provides concrete generic implementations of all + methods except for __getitem__, __setitem__, __delitem__, + __iter__, and __len__. + + """ + + @abstractmethod + def __setitem__(self, key, value): + raise KeyError + + @abstractmethod + def __delitem__(self, key): + raise KeyError + + __marker = object() + + def pop(self, key, default=__marker): + '''D.pop(k[,d]) -> v, remove specified key and return the corresponding value. + If key is not found, d is returned if given, otherwise KeyError is raised. + ''' + try: + value = self[key] + except KeyError: + if default is self.__marker: + raise + return default + else: + del self[key] + return value + + def popitem(self): + '''D.popitem() -> (k, v), remove and return some (key, value) pair + as a 2-tuple; but raise KeyError if D is empty. + ''' + try: + key = next(iter(self)) + except StopIteration: + raise KeyError + value = self[key] + del self[key] + return key, value + + def clear(self): + 'D.clear() -> None. Remove all items from D.' + try: + while True: + self.popitem() + except KeyError: + pass + + def update(*args, **kwds): + ''' D.update([E, ]**F) -> None. Update D from mapping/iterable E and F. + If E present and has a .keys() method, does: for k in E: D[k] = E[k] + If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v + In either case, this is followed by: for k, v in F.items(): D[k] = v + ''' + if not args: + raise TypeError("descriptor 'update' of 'MutableMapping' object " + "needs an argument") + self = args[0] + args = args[1:] + if len(args) > 1: + raise TypeError('update expected at most 1 arguments, got %d' % + len(args)) + if args: + other = args[0] + if isinstance(other, Mapping): + for key in other: + self[key] = other[key] + elif hasattr(other, "keys"): + for key in other.keys(): + self[key] = other[key] + else: + for key, value in other: + self[key] = value + for key, value in kwds.items(): + self[key] = value + + def setdefault(self, key, default=None): + 'D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D' + try: + return self[key] + except KeyError: + self[key] = default + return default + +MutableMapping.register(dict) + + +### SEQUENCES ### + + +class Sequence(Sized, Iterable, Container): + """All the operations on a read-only sequence. + + Concrete subclasses must override __new__ or __init__, + __getitem__, and __len__. + """ + + @abstractmethod + def __getitem__(self, index): + raise IndexError + + def __iter__(self): + i = 0 + try: + while True: + v = self[i] + yield v + i += 1 + except IndexError: + return + + def __contains__(self, value): + for v in self: + if v == value: + return True + return False + + def __reversed__(self): + for i in reversed(range(len(self))): + yield self[i] + + def index(self, value): + '''S.index(value) -> integer -- return first index of value. + Raises ValueError if the value is not present. + ''' + for i, v in enumerate(self): + if v == value: + return i + raise ValueError + + def count(self, value): + 'S.count(value) -> integer -- return number of occurrences of value' + return sum(1 for v in self if v == value) + +Sequence.register(tuple) +Sequence.register(basestring) +Sequence.register(buffer) +Sequence.register(xrange) + + +class MutableSequence(Sequence): + + """All the operations on a read-only sequence. + + Concrete subclasses must provide __new__ or __init__, + __getitem__, __setitem__, __delitem__, __len__, and insert(). + + """ + + @abstractmethod + def __setitem__(self, index, value): + raise IndexError + + @abstractmethod + def __delitem__(self, index): + raise IndexError + + @abstractmethod + def insert(self, index, value): + 'S.insert(index, object) -- insert object before index' + raise IndexError + + def append(self, value): + 'S.append(object) -- append object to the end of the sequence' + self.insert(len(self), value) + + def reverse(self): + 'S.reverse() -- reverse *IN PLACE*' + n = len(self) + for i in range(n//2): + self[i], self[n-i-1] = self[n-i-1], self[i] + + def extend(self, values): + 'S.extend(iterable) -- extend sequence by appending elements from the iterable' + for v in values: + self.append(v) + + def pop(self, index=-1): + '''S.pop([index]) -> item -- remove and return item at index (default last). + Raise IndexError if list is empty or index is out of range. + ''' + v = self[index] + del self[index] + return v + + def remove(self, value): + '''S.remove(value) -- remove first occurrence of value. + Raise ValueError if the value is not present. + ''' + del self[self.index(value)] + + def __iadd__(self, values): + self.extend(values) + return self + +MutableSequence.register(list) |