# -*- coding: utf-8 -*-
"""
Data Structures
===============
Defines various data structures classes:
- :class:`colour.utilities.Structure`: An object similar to C/C++ structured
type.
- :class:`colour.utilities.Lookup`: A *dict* sub-class acting as a lookup to
retrieve keys by values.
- :class:`colour.utilities.CaseInsensitiveMapping`: A case insensitive
mapping allowing values retrieving from keys while ignoring the key case.
References
----------
- :cite:`Mansencalc` : Mansencal, T. (n.d.). Lookup. Retrieved from
https://github.com/KelSolaar/Foundations/blob/develop/foundations/\
data_structures.py
- :cite:`Mansencald` : Mansencal, T. (n.d.). Structure. Retrieved from
https://github.com/KelSolaar/Foundations/blob/develop/foundations/\
data_structures.py
- :cite:`Reitza` : Reitz, K. (n.d.). CaseInsensitiveDict. Retrieved from
https://github.com/kennethreitz/requests/blob/v1.2.3/requests/\
structures.py#L37
"""
from __future__ import division, unicode_literals
from collections import Mapping, MutableMapping
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2019 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['Structure', 'Lookup', 'CaseInsensitiveMapping']
class Structure(dict):
"""
Defines an object similar to C/C++ structured type.
Other Parameters
----------------
\\*args : list, optional
Arguments.
\\**kwargs : dict, optional
Key / Value pairs.
References
----------
:cite:`Mansencald`
Examples
--------
>>> person = Structure(first_name='Doe', last_name='John', gender='male')
>>> # Doctests skip for Python 2.x compatibility.
>>> person.first_name # doctest: +SKIP
'Doe'
>>> sorted(person.keys())
['first_name', 'gender', 'last_name']
>>> # Doctests skip for Python 2.x compatibility.
>>> person['gender'] # doctest: +SKIP
'male'
"""
def __init__(self, *args, **kwargs):
super(Structure, self).__init__(*args, **kwargs)
self.__dict__ = self
class Lookup(dict):
"""
Extends *dict* type to provide a lookup by value(s).
Methods
-------
keys_from_value
first_key_from_value
References
----------
:cite:`Mansencalc`
Examples
--------
>>> person = Lookup(first_name='Doe', last_name='John', gender='male')
>>> person.first_key_from_value('Doe')
'first_name'
>>> persons = Lookup(John='Doe', Jane='Doe', Luke='Skywalker')
>>> sorted(persons.keys_from_value('Doe'))
['Jane', 'John']
"""
def keys_from_value(self, value):
"""
Gets the keys with given value.
Parameters
----------
value : object
Value.
Returns
-------
object
Keys.
"""
keys = []
for key, data in self.items():
matching = data == value
try:
matching = all(matching)
except TypeError:
matching = all((matching, ))
if matching:
keys.append(key)
return keys
def first_key_from_value(self, value):
"""
Gets the first key with given value.
Parameters
----------
value : object
Value.
Returns
-------
object
Key.
"""
try:
return self.keys_from_value(value)[0]
except IndexError:
pass
class CaseInsensitiveMapping(MutableMapping):
"""
Implements a case-insensitive mutable mapping / *dict* object.
Allows values retrieving from keys while ignoring the key case.
The keys are expected to be unicode or string-like objects supporting the
:meth:`str.lower` method.
Parameters
----------
data : dict
*dict* of data to store into the mapping at initialisation.
Other Parameters
----------------
\\**kwargs : dict, optional
Key / Value pairs to store into the mapping at initialisation.
Methods
-------
__setitem__
__getitem__
__delitem__
__contains__
__iter__
__len__
__eq__
__ne__
__repr__
copy
lower_items
Warning
-------
The keys are expected to be unicode or string-like objects.
References
----------
:cite:`Reitza`
Examples
--------
>>> methods = CaseInsensitiveMapping({'McCamy': 1, 'Hernandez': 2})
>>> methods['mccamy']
1
"""
def __init__(self, data=None, **kwargs):
self._data = dict()
self.update({} if data is None else data, **kwargs)
@property
def data(self):
"""
Getter and setter property for the data.
Parameters
----------
value : dict
Value to set the data with.
Returns
-------
dict
Data.
"""
return self._data
def __setitem__(self, item, value):
"""
Sets given item with given value.
The item is stored as lower in the mapping while the original name and
its value are stored together as the value in a *tuple*:
{"item.lower()": ("item", value)}
Parameters
----------
item : object
Attribute.
value : object
Value.
"""
self._data[item.lower()] = (item, value)
def __getitem__(self, item):
"""
Returns the value of given item.
The item value is retrieved using its lower name in the mapping.
Parameters
----------
item : unicode
Item name.
Returns
-------
object
Item value.
"""
return self._data[item.lower()][1]
def __delitem__(self, item):
"""
Deletes the item with given name.
The item is deleted from the mapping using its lower name.
Parameters
----------
item : unicode
Item name.
"""
del self._data[item.lower()]
def __contains__(self, item):
"""
Returns if the mapping contains given item.
Parameters
----------
item : unicode
Item name.
Returns
-------
bool
Is item in mapping.
"""
return item.lower() in self._data
def __iter__(self):
"""
Iterates over the items names in the mapping.
The item names returned are the original input ones.
Returns
-------
generator
Item names.
"""
return (item for item, value in self._data.values())
def __len__(self):
"""
Returns the items count.
Returns
-------
int
Items count.
"""
return len(self._data)
def __eq__(self, item):
"""
Returns the equality with given object.
Parameters
----------
item
Object item.
Returns
-------
bool
Equality.
"""
if isinstance(item, Mapping):
item = CaseInsensitiveMapping(item)
else:
return NotImplemented
return dict(self.lower_items()) == dict(item.lower_items())
def __ne__(self, item):
"""
Returns the inequality with given object.
Parameters
----------
item
Object item.
Returns
-------
bool
Inequality.
"""
return not (self == item)
def __repr__(self):
"""
Returns the mapping representation with the original item names.
Returns
-------
unicode
Mapping representation.
"""
return '{0}({1})'.format(self.__class__.__name__, dict(self.items()))
def copy(self):
"""
Returns a copy of the mapping.
Returns
-------
CaseInsensitiveMapping
Mapping copy.
Notes
-----
- The :class:`colour.utilities.CaseInsensitiveMapping` class copy
returned is a simple *copy* not a *deepcopy*.
"""
return CaseInsensitiveMapping(self._data.values())
def lower_items(self):
"""
Iterates over the lower items names.
Returns
-------
generator
Lower item names.
"""
return ((item, value[1]) for (item, value) in self._data.items())