Coverage for pygeodesy/basics.py: 91%
193 statements
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« prev ^ index » next coverage.py v7.2.2, created at 2023-04-02 08:40 -0400
2# -*- coding: utf-8 -*-
4u'''Some, basic definitions, functions and dependencies.
6Use env variable C{PYGEODESY_XPACKAGES} to avoid import of dependencies
7C{geographiclib}, C{numpy} and/or C{scipy}. Set C{PYGEODESY_XPACKAGES}
8to a comma-separated list of package names to be excluded from import.
9'''
10# make sure int/int division yields float quotient
11from __future__ import division
12division = 1 / 2 # .albers, .azimuthal, .constants, etc., .utily
13if not division:
14 raise ImportError('%s 1/2 == %s' % ('division', division))
15del division
17from pygeodesy.errors import _AssertionError, _AttributeError, _ImportError, \
18 _TypeError, _TypesError, _ValueError, _xkwds_get
19from pygeodesy.interns import MISSING, NN, _by_, _DOT_, _ELLIPSIS4_, _enquote, \
20 _EQUAL_, _in_, _invalid_, _N_A_, _name_, _SPACE_, \
21 _splituple, _UNDER_, _version_
22from pygeodesy.lazily import _ALL_LAZY, _ALL_MODS as _MODS, _FOR_DOCS, \
23 _getenv, _sys_version_info2
25from copy import copy as _copy, deepcopy as _deepcopy
26from math import copysign as _copysign
27import inspect as _inspect
29__all__ = _ALL_LAZY.basics
30__version__ = '23.03.29'
32_0_0 = 0.0 # see .constants
33_below_ = 'below'
34_cannot_ = 'cannot'
35_list_tuple_types = (list, tuple)
36_odd_ = 'odd'
37_required_ = 'required'
38_PYGEODESY_XPACKAGES_ = 'PYGEODESY_XPACKAGES'
39_XPACKAGES = _splituple(_getenv(_PYGEODESY_XPACKAGES_, NN))
41try: # Luciano Ramalho, "Fluent Python", page 395, O'Reilly, 2016
42 from numbers import Integral as _Ints, Real as _Scalars
43except ImportError:
44 try:
45 _Ints = int, long # int objects (C{tuple})
46 except NameError: # Python 3+
47 _Ints = int, # int objects (C{tuple})
48 _Scalars = _Ints + (float,)
50try:
51 try: # use C{from collections.abc import ...} in Python 3.9+
52 from collections.abc import Sequence as _Sequence # in .points
53 except ImportError: # no .abc in Python 3.8- and 2.7-
54 from collections import Sequence as _Sequence # in .points
55 if isinstance([], _Sequence) and isinstance((), _Sequence):
56 # and isinstance(range(1), _Sequence):
57 _Seqs = _Sequence
58 else:
59 raise ImportError # _AssertionError
60except ImportError:
61 _Sequence = tuple # immutable for .points._Basequence
62 _Seqs = list, _Sequence # , range for function len2 below
64try:
65 _Bytes = unicode, bytearray # PYCHOK expected
66 _Strs = basestring, str # XXX , bytes
68 def _NOP(x):
69 '''NOP, pass thru.'''
70 return x
72 str2ub = ub2str = _NOP # avoids UnicodeDecodeError
74 def _Xstr(exc): # PYCHOK no cover
75 '''I{Invoke only with caught ImportError} B{C{exc}}.
77 C{... "cannot import name _distributor_init" ...}
79 only for C{numpy}, C{scipy} import errors occurring
80 on arm64 Apple Silicon running macOS' Python 2.7.16?
81 '''
82 t = str(exc)
83 if '_distributor_init' in t:
84 from sys import exc_info
85 from traceback import extract_tb
86 tb = exc_info()[2] # 3-tuple (type, value, traceback)
87 t4 = extract_tb(tb, 1)[0] # 4-tuple (file, line, name, 'import ...')
88 t = _SPACE_(_cannot_, t4[3] or _N_A_)
89 del tb, t4
90 return t
92except NameError: # Python 3+
93 from pygeodesy.interns import _utf_8_
95 _Bytes = bytes, bytearray
96 _Strs = str, # tuple
97 _Xstr = str
99 def str2ub(sb):
100 '''Convert C{str} to C{unicode bytes}.
101 '''
102 if isinstance(sb, _Strs):
103 sb = sb.encode(_utf_8_)
104 return sb
106 def ub2str(ub):
107 '''Convert C{unicode bytes} to C{str}.
108 '''
109 if isinstance(ub, _Bytes):
110 ub = str(ub.decode(_utf_8_))
111 return ub
114def clips(sb, limit=50, white=NN):
115 '''Clip a string to the given length limit.
117 @arg sb: String (C{str} or C{bytes}).
118 @kwarg limit: Length limit (C{int}).
119 @kwarg white: Optionally, replace all whitespace (C{str}).
121 @return: The clipped or unclipped B{C{sb}}.
122 '''
123 T = type(sb)
124 if len(sb) > limit > 8:
125 h = limit // 2
126 sb = T(_ELLIPSIS4_).join((sb[:h], sb[-h:]))
127 if white: # replace whitespace
128 sb = T(white).join(sb.split())
129 return sb
132def copysign0(x, y):
133 '''Like C{math.copysign(x, y)} except C{zero}, I{unsigned}.
135 @return: C{math.copysign(B{x}, B{y})} if B{C{x}} else
136 C{type(B{x})(0)}.
137 '''
138 return _copysign(x, (y if y else 0)) if x else copytype(0, x)
141def copytype(x, y):
142 '''Return the value of B{x} as C{type} of C{y}.
144 @return: C{type(B{y})(B{x})}.
145 '''
146 return type(y)(x if x else _0_0)
149def halfs2(str2):
150 '''Split a string in 2 halfs.
152 @arg str2: String to split (C{str}).
154 @return: 2-Tuple (_1st, _2nd) half (C{str}).
156 @raise ValueError: Zero or odd C{len}(B{C{str2}}).
157 '''
158 h, r = divmod(len(str2), 2)
159 if r or not h:
160 raise _ValueError(str2=str2, txt=_odd_)
161 return str2[:h], str2[h:]
164def isbool(obj):
165 '''Check whether an object is C{bool}ean.
167 @arg obj: The object (any C{type}).
169 @return: C{True} if B{C{obj}} is C{bool}ean,
170 C{False} otherwise.
171 '''
172 return isinstance(obj, bool) # and (obj is False
173# or obj is True)
175if isbool(1) or isbool(0): # PYCHOK assert
176 raise _AssertionError(isbool=1)
178if _FOR_DOCS: # XXX avoid epidoc Python 2.7 error
180 def isclass(obj):
181 '''Return C{True} if B{C{obj}} is a C{class} or C{type}.
183 @see: Python's C{inspect.isclass}.
184 '''
185 return _inspect.isclass(obj)
186else:
187 isclass = _inspect.isclass
190def iscomplex(obj):
191 '''Check whether an object is C{complex}.
193 @arg obj: The object (any C{type}).
195 @return: C{True} if B{C{obj}} is C{complex},
196 C{False} otherwise.
197 '''
198 # hasattr('conjugate'), hasattr('real') and hasattr('imag')
199 return isinstance(obj, complex) # numbers.Complex?
202def isfloat(obj):
203 '''Check whether an object is a C{float} or float C{str}.
205 @arg obj: The object (any C{type}).
207 @return: C{True} if B{C{obj}} is a C{float},
208 C{False} otherwise.
209 '''
210 try:
211 return isinstance( obj, float) or (isstr(obj)
212 and isinstance(float(obj), float))
213 except (TypeError, ValueError):
214 return False
217try:
218 isidentifier = str.isidentifier # Python 3, must be str
219except AttributeError: # Python 2-
221 def isidentifier(obj):
222 '''Return C{True} if B{C{obj}} is a valid Python identifier.
223 '''
224 return bool(obj and obj.replace(_UNDER_, NN).isalnum()
225 and not obj[:1].isdigit())
228def isinstanceof(obj, *classes):
229 '''Check an instance of one or several C{classes}.
231 @arg obj: The instance (C{any}).
232 @arg classes: One or more classes (C{class}).
234 @return: C{True} if B{C{obj}} is in instance of
235 one of the B{C{classes}}.
236 '''
237 return isinstance(obj, classes)
240def isint(obj, both=False):
241 '''Check for C{int} type or an integer C{float} value.
243 @arg obj: The object (any C{type}).
244 @kwarg both: If C{true}, check C{float} and L{Fsum}
245 type and value (C{bool}).
247 @return: C{True} if B{C{obj}} is C{int} or I{integer}
248 C{float} or L{Fsum}, C{False} otherwise.
250 @note: Both C{isint(True)} and C{isint(False)} return
251 C{False} (and no longer C{True}).
252 '''
253 if isinstance(obj, _Ints) and not isbool(obj):
254 return True
255 elif both: # and isinstance(obj, (float, Fsum)) ...
256 try: # ... NOT , Scalars) to include Fsum!
257 return obj.is_integer()
258 except AttributeError:
259 pass # XXX float(int(obj)) == obj?
260 return False
263try:
264 from keyword import iskeyword # Python 2.7+
265except ImportError:
267 def iskeyword(unused):
268 '''Not Implemented. Return C{False}, always.
269 '''
270 return False
273def islistuple(obj, minum=0):
274 '''Check for list or tuple C{type} with a minumal length.
276 @arg obj: The object (any C{type}).
277 @kwarg minum: Minimal C{len} required C({int}).
279 @return: C{True} if B{C{obj}} is C{list} or C{tuple} with
280 C{len} at least B{C{minum}}, C{False} otherwise.
281 '''
282 return type(obj) in _list_tuple_types and len(obj) >= (minum or 0)
285def isodd(x):
286 '''Is B{C{x}} odd?
288 @arg x: Value (C{scalar}).
290 @return: C{True} if B{C{x}} is odd,
291 C{False} otherwise.
292 '''
293 return bool(int(x) & 1) # == bool(int(x) % 2)
296def isscalar(obj):
297 '''Check for scalar types.
299 @arg obj: The object (any C{type}).
301 @return: C{True} if B{C{obj}} is C{scalar}, C{False} otherwise.
302 '''
303 return isinstance(obj, _Scalars) and not isbool(obj)
306def issequence(obj, *excls):
307 '''Check for sequence types.
309 @arg obj: The object (any C{type}).
310 @arg excls: Classes to exclude (C{type}), all positional.
312 @note: Excluding C{tuple} implies excluding C{namedtuple}.
314 @return: C{True} if B{C{obj}} is a sequence, C{False} otherwise.
315 '''
316 return isinstance(obj, _Seqs) and not (excls and isinstance(obj, excls))
319def isstr(obj):
320 '''Check for string types.
322 @arg obj: The object (any C{type}).
324 @return: C{True} if B{C{obj}} is C{str}, C{False} otherwise.
325 '''
326 return isinstance(obj, _Strs)
329def issubclassof(Sub, *Supers):
330 '''Check whether a class is a sub-class of some other class(es).
332 @arg Sub: The sub-class (C{class}).
333 @arg Supers: One or more C(super) classes (C{class}).
335 @return: C{True} if B{C{Sub}} is a sub-class of any B{C{Supers}},
336 C{False} if not (C{bool}) or C{None} if B{C{Sub}} is not
337 a class or if no B{C{Supers}} are given or none of those
338 are a class.
339 '''
340 if isclass(Sub):
341 t = tuple(S for S in Supers if isclass(S))
342 if t:
343 return bool(issubclass(Sub, t))
344 return None
347def len2(items):
348 '''Make built-in function L{len} work for generators, iterators,
349 etc. since those can only be started exactly once.
351 @arg items: Generator, iterator, list, range, tuple, etc.
353 @return: 2-Tuple C{(n, items)} of the number of items (C{int})
354 and the items (C{list} or C{tuple}).
355 '''
356 if not isinstance(items, _Seqs): # NOT hasattr(items, '__len__'):
357 items = list(items)
358 return len(items), items
361def map1(fun1, *xs): # XXX map_
362 '''Apply each argument to a single-argument function and
363 return a C{tuple} of results.
365 @arg fun1: 1-Arg function to apply (C{callable}).
366 @arg xs: Arguments to apply (C{any positional}).
368 @return: Function results (C{tuple}).
369 '''
370 return tuple(map(fun1, xs)) # note xs, not *xs
373def map2(func, *xs):
374 '''Apply arguments to a function and return a C{tuple} of results.
376 Unlike Python 2's built-in L{map}, Python 3+ L{map} returns a
377 L{map} object, an iterator-like object which generates the
378 results only once. Converting the L{map} object to a tuple
379 maintains the Python 2 behavior.
381 @arg func: Function to apply (C{callable}).
382 @arg xs: Arguments to apply (C{list, tuple, ...}).
384 @return: Function results (C{tuple}).
385 '''
386 return tuple(map(func, *xs)) # note *xs, not xs
389def neg(x):
390 '''Negate C{x} unless C{zero} or C{NEG0}.
392 @return: C{-B{x}} if B{C{x}} else C{0.0}.
393 '''
394 return -x if x else _0_0
397def neg_(*xs):
398 '''Negate all of C{xs} with L{neg}.
400 @return: A C{tuple(neg(x) for x in B{xs})}.
401 '''
402 return tuple(map(neg, xs)) # like map1
405def signBit(x):
406 '''Return C{signbit(B{x})}, like C++.
408 @return: C{True} if C{B{x} < 0} or C{NEG0} (C{bool}).
409 '''
410 return x < 0 or _MODS.constants.isneg0(x)
413def _signOf(x, off):
414 '''(INTERNAL) Return the sign of B{C{x}} versus B{C{off}}.
415 '''
416 return +1 if x > off else (-1 if x < off else 0)
419def signOf(x):
420 '''Return sign of C{x} as C{int}.
422 @return: -1, 0 or +1 (C{int}).
423 '''
424 try:
425 s = x.signOf() # Fsum instance?
426 except AttributeError:
427 s = _signOf(x, 0)
428 return s
431def splice(iterable, n=2, **fill):
432 '''Split an iterable into C{n} slices.
434 @arg iterable: Items to be spliced (C{list}, C{tuple}, ...).
435 @kwarg n: Number of slices to generate (C{int}).
436 @kwarg fill: Optional fill value for missing items.
438 @return: A generator for each of B{C{n}} slices,
439 M{iterable[i::n] for i=0..n}.
441 @raise TypeError: Invalid B{C{n}}.
443 @note: Each generated slice is a C{tuple} or a C{list},
444 the latter only if the B{C{iterable}} is a C{list}.
446 @example:
448 >>> from pygeodesy import splice
450 >>> a, b = splice(range(10))
451 >>> a, b
452 ((0, 2, 4, 6, 8), (1, 3, 5, 7, 9))
454 >>> a, b, c = splice(range(10), n=3)
455 >>> a, b, c
456 ((0, 3, 6, 9), (1, 4, 7), (2, 5, 8))
458 >>> a, b, c = splice(range(10), n=3, fill=-1)
459 >>> a, b, c
460 ((0, 3, 6, 9), (1, 4, 7, -1), (2, 5, 8, -1))
462 >>> tuple(splice(list(range(9)), n=5))
463 ([0, 5], [1, 6], [2, 7], [3, 8], [4])
465 >>> splice(range(9), n=1)
466 <generator object splice at 0x0...>
467 '''
468 if not isint(n):
469 raise _TypeError(n=n)
471 t = iterable
472 if not isinstance(t, (list, tuple)):
473 t = tuple(t) # force tuple, also for PyPy3
475 if n > 1:
476 if fill:
477 fill = _xkwds_get(fill, fill=MISSING)
478 if fill is not MISSING:
479 m = len(t) % n
480 if m > 0: # same type fill
481 t = t + type(t)((fill,)) * (n - m)
482 for i in range(n):
483 # XXX t[i::n] chokes PyChecker
484 yield t[slice(i, None, n)]
485 else:
486 yield t
489def unsigned0(x):
490 '''Return C{0.0} unsigned.
492 @return: C{B{x}} if B{C{x}} else C{0.0}.
493 '''
494 return x if x else _0_0
497def _xargs_names(callabl):
498 '''(INTERNAL) Get the C{callabl}'s args names.
499 '''
500 try:
501 args_kwds = _inspect.signature(callabl).parameters.keys()
502 except AttributeError: # .signature new Python 3+
503 args_kwds = _inspect.getargspec(callabl).args
504 return tuple(args_kwds)
507def _xcopy(inst, deep=False):
508 '''(INTERNAL) Copy an object, shallow or deep.
510 @arg inst: The object to copy (any C{type}).
511 @kwarg deep: If C{True} make a deep, otherwise
512 a shallow copy (C{bool}).
514 @return: The copy of B{C{inst}}.
515 '''
516 return _deepcopy(inst) if deep else _copy(inst)
519def _xdup(inst, **items):
520 '''(INTERNAL) Duplicate an object, replacing some attributes.
522 @arg inst: The object to copy (any C{type}).
523 @kwarg items: Attributes to be changed (C{any}).
525 @return: Shallow duplicate of B{C{inst}} with modified
526 attributes, if any B{C{items}}.
528 @raise AttributeError: Some B{C{items}} invalid.
529 '''
530 d = _xcopy(inst, deep=False)
531 for n, v in items.items():
532 if not hasattr(d, n):
533 t = _MODS.named.classname(inst)
534 t = _SPACE_(_DOT_(t, n), _invalid_)
535 raise _AttributeError(txt=t, this=inst, **items)
536 setattr(d, n, v)
537 return d
540def _xgeographiclib(where, *required):
541 '''(INTERNAL) Import C{geographiclib} and check required version
542 '''
543 try:
544 _xpackage(_xgeographiclib)
545 import geographiclib
546 except ImportError as x:
547 raise _xImportError(x, where)
548 return _xversion(geographiclib, where, *required)
551def _xImportError(x, where, **name):
552 '''(INTERNAL) Embellish an C{ImportError}.
553 '''
554 t = _SPACE_(_required_, _by_, _xwhere(where, **name))
555 return _ImportError(_Xstr(x), txt=t, cause=x)
558def _xinstanceof(*Types, **name_value_pairs):
559 '''(INTERNAL) Check C{Types} of all C{name=value} pairs.
561 @arg Types: One or more classes or types (C{class}),
562 all positional.
563 @kwarg name_value_pairs: One or more C{B{name}=value} pairs
564 with the C{value} to be checked.
566 @raise TypeError: One of the B{C{name_value_pairs}} is not
567 an instance of any of the B{C{Types}}.
568 '''
569 for n, v in name_value_pairs.items():
570 if not isinstance(v, Types):
571 raise _TypesError(n, v, *Types)
574def _xnumpy(where, *required):
575 '''(INTERNAL) Import C{numpy} and check required version
576 '''
577 try:
578 _xpackage(_xnumpy)
579 import numpy
580 except ImportError as x:
581 raise _xImportError(x, where)
582 return _xversion(numpy, where, *required)
585def _xpackage(_xpkg):
586 '''(INTERNAL) Check dependency to be excluded.
587 '''
588 n = _xpkg.__name__[2:]
589 if n in _XPACKAGES:
590 x = _SPACE_(n, _in_, _PYGEODESY_XPACKAGES_)
591 e = _enquote(_getenv(_PYGEODESY_XPACKAGES_, NN))
592 raise ImportError(_EQUAL_(x, e))
595def _xor(x, *xs):
596 '''(INTERNAL) Exclusive-or C{x} and C{xs}.
597 '''
598 for x_ in xs:
599 x ^= x_
600 return x
603def _xscipy(where, *required):
604 '''(INTERNAL) Import C{scipy} and check required version
605 '''
606 try:
607 _xpackage(_xscipy)
608 import scipy
609 except ImportError as x:
610 raise _xImportError(x, where)
611 return _xversion(scipy, where, *required)
614def _xsubclassof(*Classes, **name_value_pairs):
615 '''(INTERNAL) Check (super) class of all C{name=value} pairs.
617 @arg Classes: One or more classes or types (C{class}),
618 all positional.
619 @kwarg name_value_pairs: One or more C{B{name}=value} pairs
620 with the C{value} to be checked.
622 @raise TypeError: One of the B{C{name_value_pairs}} is not
623 a (sub-)class of any of the B{C{Classes}}.
624 '''
625 for n, v in name_value_pairs.items():
626 if not issubclassof(v, *Classes):
627 raise _TypesError(n, v, *Classes)
630def _xversion(package, where, *required, **name): # in .karney
631 '''(INTERNAL) Check the C{package} version vs B{C{required}}.
632 '''
633 n = len(required)
634 if n:
635 t = _xversion_info(package)
636 if t[:n] < required:
637 t = _SPACE_(package.__name__, _version_, _DOT_(*t),
638 _below_, _DOT_(*required),
639 _required_, _by_, _xwhere(where, **name))
640 raise ImportError(t)
641 return package
644def _xversion_info(package): # in .karney
645 '''(INTERNAL) Get the C{package.__version_info__} as a 2- or
646 3-tuple C{(major, minor, revision)} if C{int}s.
647 '''
648 try:
649 t = package.__version_info__
650 except AttributeError:
651 t = package.__version__.strip()
652 t = t.replace(_DOT_, _SPACE_).split()[:3]
653 return map2(int, t)
656def _xwhere(where, **name):
657 '''(INTERNAL) Get the fully qualified name.
658 '''
659 m = _MODS.named.modulename(where, prefixed=True)
660 n = name.get(_name_, NN)
661 if n:
662 m = _DOT_(m, n)
663 return m
666if _sys_version_info2 < (3, 10): # see .errors
667 _zip = zip # PYCHOK exported
668else: # Python 3.10+
670 def _zip(*args):
671 return zip(*args, strict=True)
673# **) MIT License
674#
675# Copyright (C) 2016-2023 -- mrJean1 at Gmail -- All Rights Reserved.
676#
677# Permission is hereby granted, free of charge, to any person obtaining a
678# copy of this software and associated documentation files (the "Software"),
679# to deal in the Software without restriction, including without limitation
680# the rights to use, copy, modify, merge, publish, distribute, sublicense,
681# and/or sell copies of the Software, and to permit persons to whom the
682# Software is furnished to do so, subject to the following conditions:
683#
684# The above copyright notice and this permission notice shall be included
685# in all copies or substantial portions of the Software.
686#
687# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
688# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
689# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
690# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
691# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
692# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
693# OTHER DEALINGS IN THE SOFTWARE.