ceph/src/boost/tools/build/src/util/sequence.py

   1 #  (C) Copyright David Abrahams 2002. Permission to copy, use, modify, sell and
   2 #  distribute this software is granted provided this copyright notice appears in
   3 #  all copies. This software is provided "as is" without express or implied
   4 #  warranty, and with no claim as to its suitability for any purpose.
   5
   6 import operator
   7
   8 from b2.util import is_iterable
   9
  10
  11 def unique (values, stable=False):
  12     assert is_iterable(values)
  13     if stable:
  14         s = set()
  15         r = []
  16         for v in values:
  17             if not v in s:
  18                 r.append(v)
  19                 s.add(v)
  20         return r
  21     else:
  22         return list(set(values))
  23
  24 def max_element (elements, ordered = None):
  25     """ Returns the maximum number in 'elements'. Uses 'ordered' for comparisons,
  26         or '<' is none is provided.
  27     """
  28     assert is_iterable(elements)
  29     assert callable(ordered) or ordered is None
  30     if not ordered: ordered = operator.lt
  31
  32     max = elements [0]
  33     for e in elements [1:]:
  34         if ordered (max, e):
  35             max = e
  36
  37     return max
  38
  39 def select_highest_ranked (elements, ranks):
  40     """ Returns all of 'elements' for which corresponding element in parallel
  41         list 'rank' is equal to the maximum value in 'rank'.
  42     """
  43     assert is_iterable(elements)
  44     assert is_iterable(ranks)
  45     if not elements:
  46         return []
  47
  48     max_rank = max_element (ranks)
  49
  50     result = []
  51     while elements:
  52         if ranks [0] == max_rank:
  53             result.append (elements [0])
  54
  55         elements = elements [1:]
  56         ranks = ranks [1:]
  57
  58     return result