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# -*- coding: utf-8 -*- 

 

u'''Some, basic definitions and functions. 

''' 

# make sure int/int division yields float quotient 

from __future__ import division 

division = 1 / 2 # .albers, .datums, .ellipsoidalVincenty, .ellipsoids, 

if not division: # .elliptic, .etm, .fmath, .formy, .lcc, .osgr, .utily 

raise ImportError('%s 1/2 == %s' % ('division', division)) 

del division 

 

from pygeodesy.errors import _IsnotError, _TypeError, _TypesError, \ 

_ValueError, _xkwds_get 

from pygeodesy.interns import EPS0, MISSING, NEG0, NN, _by_, _DOT_, \ 

_name_, _SPACE_, _UNDER_, _utf_8_, \ 

_version_, _0_0 

from pygeodesy.lazily import _ALL_LAZY, _FOR_DOCS 

 

from copy import copy as _copy, deepcopy as _deepcopy 

from inspect import isclass as _isclass 

from math import copysign as _copysign, isinf, isnan 

 

__all__ = _ALL_LAZY.basics 

__version__ = '21.06.30' 

 

try: # Luciano Ramalho, "Fluent Python", page 395, O'Reilly, 2016 

from numbers import Integral as _Ints # int objects 

except ImportError: # PYCHOK no cover 

try: 

_Ints = int, long # int objects (C{tuple}) 

except NameError: # Python 3+ 

_Ints = int, # int objects (C{tuple}) 

 

try: # similarly ... 

from numbers import Real as _Scalars # scalar objects 

except ImportError: # PYCHOK no cover 

try: 

_Scalars = int, long, float # scalar objects (C{tuple}) 

except NameError: 

_Scalars = int, float # scalar objects (C{tuple}) 

 

try: 

try: # use C{from collections.abc import ...} in Python 3.9+ 

from collections.abc import Sequence as _Sequence # imported by .points 

except ImportError: # no .abc in Python 2.7- 

from collections import Sequence as _Sequence # imported by .points 

if isinstance([], _Sequence) and isinstance((), _Sequence): 

# and isinstance(range(1), _Sequence): 

_Seqs = _Sequence 

else: 

raise ImportError # _AssertionError 

except ImportError: # PYCHOK no cover 

_Sequence = tuple # immutable for .points._Basequence 

_Seqs = list, _Sequence # , range for function len2 below 

 

try: 

_Bytes = unicode, bytearray # PYCHOK expected 

_Strs = basestring, str 

except NameError: # Python 3+ 

_Bytes = bytes, bytearray 

_Strs = str, 

 

 

def clips(bstr, limit=50, white=NN): 

'''Clip a string to the given length limit. 

 

@arg bstr: String (C{bytes} or C{str}). 

@kwarg limit: Length limit (C{int}). 

@kwarg white: Optionally, replace all whitespace (C{str}). 

 

@return: The clipped or unclipped B{C{bstr}}. 

''' 

if len(bstr) > limit > 8: 

h = limit // 2 

bstr = NN(bstr[:h], type(bstr)('....'), bstr[-h:]) 

if white: # replace whitespace 

bstr = type(bstr)(white).join(bstr.split()) 

return bstr 

 

 

def copysign0(x, y): 

'''Like C{math.copysign(x, y)} except C{zero}, I{unsigned}. 

 

@return: C{math.copysign(B{x}, B{y})} if B{C{x}} else C{0}. 

''' 

return _copysign(x, y) if x else copytype(0, x) 

 

 

def copytype(x, y): 

'''Return the value of B{x} as C{type} of C{y}. 

 

@return: C{type(B{y})(B{x})}. 

''' 

return type(y)(x) 

 

 

def halfs2(str2): 

'''Split a string in 2 halfs. 

 

@arg str2: String to split (C{str}). 

 

@return: 2-Tuple (_1st, _2nd) half (C{str}). 

 

@raise ValueError: Zero or odd C{len}(B{C{str2}}). 

''' 

h, r = divmod(len(str2), 2) 

if r or not h: 

raise _ValueError(str2=str2, txt='odd') 

return str2[:h], str2[h:] 

 

 

def isbool(obj): 

'''Check whether an object is C{bool}ean. 

 

@arg obj: The object (any C{type}). 

 

@return: C{True} if B{C{obj}} is C{bool}ean, 

C{False} otherwise. 

''' 

return isinstance(obj, bool) # and (obj is True 

# or obj is False) 

 

 

def isodd(x): 

'''Is B{C{x}} odd? 

 

@arg x: Value (C{scalar}). 

 

@return: C{True} if B{C{x}} is odd, 

C{False} otherwise. 

''' 

return bool(int(x) & 1) 

 

 

if _FOR_DOCS: # XXX avoid epidoc Python 2.7 error 

def isclass(obj): 

'''Return C{True} if B{C{obj}} is a C{class}. 

 

@see: Python's C{inspect.isclass}. 

''' 

return _isclass(obj) 

else: 

isclass = _isclass 

 

 

try: 

from math import isfinite # new in Python 3+ 

except ImportError: 

 

def isfinite(obj): 

'''Check for C{Inf} and C{NaN} values. 

 

@arg obj: Value (C{scalar}). 

 

@return: C{False} if B{C{obj}} is C{INF} or C{NAN}, 

C{True} otherwise. 

 

@raise TypeError: Non-scalar B{C{obj}}. 

''' 

if not isscalar(obj): 

raise _IsnotError(isscalar.__name__, obj=obj) 

return not (isinf(obj) or isnan(obj)) 

 

 

try: 

isidentifier = str.isidentifier # Python 3, must be str 

except AttributeError: # Python 2- 

 

def isidentifier(obj): 

'''Return C{True} if B{C{obj}} is a valid Python identifier. 

''' 

return True if (obj and obj.replace(_UNDER_, NN).isalnum() 

and not obj[:1].isdigit()) else False 

 

 

def isint(obj, both=False): 

'''Check for C{int} type or an integer C{float} value. 

 

@arg obj: The object (any C{type}). 

@kwarg both: Optionally, check C{float} type and value (C{bool}). 

 

@return: C{True} if B{C{obj}} is C{int} or an integer 

C{float}, C{False} otherwise. 

 

@note: C{isint(True)} or C{isint(False)} returns C{False} (and 

no longer C{True}). 

''' 

if both and isinstance(obj, float): # NOT _Scalars! 

try: 

return obj.is_integer() 

except AttributeError: # PYCHOK no cover 

return False # XXX float(int(obj)) == obj? 

return isinstance(obj, _Ints) and not isbool(obj) 

 

 

try: 

from keyword import iskeyword # Python 2.7+ 

except ImportError: 

 

def iskeyword(unused): 

'''Not Implemented. Return C{False}, always. 

''' 

return False 

 

 

def isnear0(x): 

'''Is B{C{x}} near zero? 

 

@arg x: Value (C{scalar}). 

 

@return: C{True} if C{abs(B{x}) < EPS0}, 

C{False} otherwise. 

 

@see: Function L{isnon0}. 

''' 

return EPS0 > x > -EPS0 

 

 

def isneg0(x): 

'''Check for L{NEG0}, negative C{0.0}. 

 

@arg x: Value (C{scalar}). 

 

@return: C{True} if B{C{x}} is C{NEG0} or C{-0.0}, 

C{False} otherwise. 

''' 

return x in (_0_0, NEG0) and _copysign(1, x) < 0 

# and str(x).startswith('-') 

 

 

def isnon0(x): 

'''Is B{C{x}} non-zero? 

 

@arg x: Value (C{scalar}). 

 

@return: C{True} if C{abs(B{x}) > EPS0}, 

C{False} otherwise. 

 

@see: Function L{isnear0}. 

''' 

return x > EPS0 or (-x) > EPS0 

 

 

def isscalar(obj): 

'''Check for scalar types. 

 

@arg obj: The object (any C{type}). 

 

@return: C{True} if B{C{obj}} is C{scalar}, C{False} otherwise. 

''' 

return isinstance(obj, _Scalars) 

 

 

def issequence(obj, *excluded): 

'''Check for sequence types. 

 

@arg obj: The object (any C{type}). 

@arg excluded: Optional exclusions (C{type}). 

 

@note: Excluding C{tuple} implies excluding C{namedtuple}. 

 

@return: C{True} if B{C{obj}} is a sequence, C{False} otherwise. 

''' 

return False if (excluded and isinstance(obj, excluded)) else \ 

isinstance(obj, _Seqs) 

 

 

def isstr(obj): 

'''Check for string types. 

 

@arg obj: The object (any C{type}). 

 

@return: C{True} if B{C{obj}} is C{str}, C{False} otherwise. 

''' 

return isinstance(obj, _Strs) 

 

 

def issubclassof(Sub, *Supers): 

'''Check whether a class is a sub-class of some class(es). 

 

@arg Sub: The sub-class (C{class}). 

@arg Supers: One or more C(super) classes (C{class}). 

 

@return: C{True} if B{C{Sub}} is a sub-class of any 

B{C{Supers}}, C{False} otherwise (C{bool}). 

''' 

if isclass(Sub): 

for S in Supers: # any() 

if isclass(S) and issubclass(Sub, S): 

return True 

return False 

 

 

def len2(items): 

'''Make built-in function L{len} work for generators, iterators, 

etc. since those can only be started exactly once. 

 

@arg items: Generator, iterator, list, range, tuple, etc. 

 

@return: 2-Tuple C{(n, items)} of the number of items (C{int}) 

and the items (C{list} or C{tuple}). 

''' 

if not isinstance(items, _Seqs): # NOT hasattr(items, '__len__'): 

items = list(items) 

return len(items), items 

 

 

def map1(fun1, *xs): # XXX map_ 

'''Apply each argument to a single-argument function and 

return a C{tuple} of results. 

 

@arg fun1: 1-Arg function to apply (C{callable}). 

@arg xs: Arguments to apply (C{any positional}). 

 

@return: Function results (C{tuple}). 

''' 

return tuple(map(fun1, xs)) # note xs, not *xs 

 

 

def map2(func, *xs): 

'''Apply arguments to a function and return a C{tuple} of results. 

 

Unlike Python 2's built-in L{map}, Python 3+ L{map} returns a 

L{map} object, an iterator-like object which generates the 

results only once. Converting the L{map} object to a tuple 

maintains Python 2 behavior. 

 

@arg func: Function to apply (C{callable}). 

@arg xs: Arguments to apply (C{list, tuple, ...}). 

 

@return: Function results (C{tuple}). 

''' 

return tuple(map(func, *xs)) # note *xs, not xs 

 

 

def neg(x): 

'''Negate C{x} unless C{zero} or C{NEG0}. 

 

@return: C{-B{x}} if B{C{x}} else C{0.0}. 

''' 

return -x if x else _0_0 

 

 

def neg_(*xs): 

'''Negate all of C{xs} with L{neg}. 

 

@return: A C{tuple(neg(x) for x in B{xs})}. 

''' 

return tuple(map(neg, xs)) # see map1 

 

 

def signOf(x): 

'''Return sign of C{x} as C{int}. 

 

@return: -1, 0 or +1 (C{int}). 

''' 

return 1 if x > 0 else (-1 if x < 0 else 0) 

 

 

def splice(iterable, n=2, **fill): 

'''Split an iterable into C{n} slices. 

 

@arg iterable: Items to be spliced (C{list}, C{tuple}, ...). 

@kwarg n: Number of slices to generate (C{int}). 

@kwarg fill: Optional fill value for missing items. 

 

@return: A generator for each of B{C{n}} slices, 

M{iterable[i::n] for i=0..n}. 

 

@raise TypeError: Invalid B{C{n}}. 

 

@note: Each generated slice is a C{tuple} or a C{list}, 

the latter only if the B{C{iterable}} is a C{list}. 

 

@example: 

 

>>> from pygeodesy import splice 

 

>>> a, b = splice(range(10)) 

>>> a, b 

((0, 2, 4, 6, 8), (1, 3, 5, 7, 9)) 

 

>>> a, b, c = splice(range(10), n=3) 

>>> a, b, c 

((0, 3, 6, 9), (1, 4, 7), (2, 5, 8)) 

 

>>> a, b, c = splice(range(10), n=3, fill=-1) 

>>> a, b, c 

((0, 3, 6, 9), (1, 4, 7, -1), (2, 5, 8, -1)) 

 

>>> tuple(splice(list(range(9)), n=5)) 

([0, 5], [1, 6], [2, 7], [3, 8], [4]) 

 

>>> splice(range(9), n=1) 

<generator object splice at 0x0...> 

''' 

if not isint(n): 

raise _TypeError(n=n) 

 

t = iterable 

if not isinstance(t, (list, tuple)): 

t = tuple(t) # force tuple, also for PyPy3 

 

if n > 1: 

if fill: 

fill = _xkwds_get(fill, fill=MISSING) 

if fill is not MISSING: 

m = len(t) % n 

if m > 0: # fill with same type 

t += type(t)((fill,)) * (n - m) 

for i in range(n): 

# XXX t[i::n] chokes PyChecker 

yield t[slice(i, None, n)] 

else: 

yield t 

 

 

def ub2str(ub): 

'''Convert C{unicode} or C{bytes} to C{str}. 

''' 

if isinstance(ub, _Bytes): 

ub = str(ub.decode(_utf_8_)) 

return ub 

 

 

def unsign0(x): 

'''Return unsigned C{0.0}. 

 

@return: C{B{x}} if B{C{x}} else C{0.0}. 

''' 

return x if x else _0_0 

 

 

def _xcopy(inst, deep=False): 

'''(INTERNAL) Copy an object, shallow or deep. 

 

@arg inst: The object to copy (any C{type}). 

@kwarg deep: If C{True} make a deep, otherwise 

a shallow copy (C{bool}). 

 

@return: The copy of B{C{inst}}. 

''' 

return _deepcopy(inst) if deep else _copy(inst) 

 

 

def _xinstanceof(*Types, **name_value_pairs): 

'''(INTERNAL) Check C{Types} of all C{name=value} pairs. 

 

@arg Types: One or more classes or types (C{class}). 

@kwarg name_value_pairs: One or more C{B{name}=value} pairs 

with the C{value} to be checked. 

 

@raise TypeError: At least one of the B{C{name_value_pairs}} 

is not any of the B{C{Types}}. 

''' 

for n, v in name_value_pairs.items(): 

if not isinstance(v, Types): 

raise _TypesError(n, v, *Types) 

 

 

def _xnumpy(where, *required): 

'''(INTERNAL) Import C{numpy} and check required version 

''' 

import numpy 

return _xversion(numpy, where, *required) 

 

 

def _xor(x, *xs): 

'''(INTERNAL) Exclusive-or C{x} and C{xs}. 

''' 

for x_ in xs: 

x ^= x_ 

return x 

 

 

def _xscipy(where, *required): 

'''(INTERNAL) Import C{scipy} and check required version 

''' 

import scipy 

return _xversion(scipy, where, *required) 

 

 

def _xsubclassof(Class, **name_value_pairs): 

'''(INTERNAL) Check super C{Class} of all C{name=value} pairs. 

 

@arg Class: A class or type (C{class}). 

@kwarg name_value_pairs: One or more C{B{name}=value} pairs 

with the C{value} to be checked. 

 

@raise TypeError: At least one of the B{C{name_value_pairs}} 

is not a sub-class of B{C{Class}}. 

''' 

for n, v in name_value_pairs.items(): 

if not issubclassof(v, Class): 

raise _TypesError(n, v, Class) 

 

 

def _xversion(package, where, *required, **name): # in .karney 

'''(INTERNAL) Check the C{package} version vs B{C{required}}. 

''' 

t = map2(int, package.__version__.split(_DOT_)[:2]) 

if t < required: 

from pygeodesy.named import modulename 

m = modulename(where, prefixed=True) 

n = name.get(_name_, NN) 

if n: 

m = _DOT_(m, n) 

t = _SPACE_(package.__name__, _version_, _DOT_.join_(*t), 

'below', _DOT_.join_(*required), 

'required', _by_, m) 

raise ImportError(t) 

return package 

 

# **) MIT License 

# 

# Copyright (C) 2016-2021 -- mrJean1 at Gmail -- All Rights Reserved. 

# 

# Permission is hereby granted, free of charge, to any person obtaining a 

# copy of this software and associated documentation files (the "Software"), 

# to deal in the Software without restriction, including without limitation 

# the rights to use, copy, modify, merge, publish, distribute, sublicense, 

# and/or sell copies of the Software, and to permit persons to whom the 

# Software is furnished to do so, subject to the following conditions: 

# 

# The above copyright notice and this permission notice shall be included 

# in all copies or substantial portions of the Software. 

# 

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 

# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 

# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 

# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 

# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 

# OTHER DEALINGS IN THE SOFTWARE.