ceph/src/boost/libs/range/doc/reference/algorithm/equal_range.qbk

   1 [/
   2     Copyright 2010 Neil Groves
   3     Distributed under the Boost Software License, Version 1.0.
   4     (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5 /]
   6 [section:equal_range equal_range]
   7
   8 [heading Prototype]
   9
  10 ``
  11 template<
  12     class ForwardRange,
  13     class Value
  14     >
  15 std::pair<typename range_iterator<ForwardRange>::type,
  16           typename range_iterator<ForwardRange>::type>
  17 equal_range(ForwardRange& rng, const Value& val);
  18
  19 template<
  20     class ForwardRange,
  21     class Value
  22     >
  23 std::pair<typename range_iterator<const ForwardRange>::type,
  24           typename range_iterator<const ForwardRange>::type>
  25 equal_range(const ForwardRange& rng, const Value& val);
  26
  27 template<
  28     class ForwardRange,
  29     class Value,
  30     class SortPredicate
  31     >
  32 std::pair<typename range_iterator<ForwardRange>::type,
  33           typename range_iterator<ForwardRange>::type>
  34 equal_range(ForwardRange& rng, const Value& val, SortPredicate pred);
  35
  36 template<
  37     class ForwardRange,
  38     class Value,
  39     class SortPredicate
  40     >
  41 std::pair<typename range_iterator<const ForwardRange>::type,
  42           typename range_iterator<const ForwardRange>::type>
  43 equal_range(const ForwardRange& rng, const Value& val, SortPredicate pred);
  44  ``
  45
  46 [heading Description]
  47
  48 `equal_range` returns a range in the form of a pair of iterators where all of the elements are equal to `val`. If no values are found that are equal to `val`, then an empty range is returned, hence `result.first == result.second`. For the non-predicate versions of `equal_range`  the equality of elements is determined by `operator<`.
  49 For the predicate versions of `equal_range` the equality of elements is determined by `pred`.
  50
  51 [heading Definition]
  52
  53 Defined in the header file `boost/range/algorithm/equal_range.hpp`
  54
  55 [heading Requirements]
  56
  57 [*For the non-predicate versions:]
  58
  59 * `ForwardRange` is a model of the __forward_range__ Concept.
  60 * `Value` is a model of the `LessThanComparableConcept`.
  61 * The ordering of objects of type `Value` is a [*/strict weak ordering/], as defined in the `LessThanComparableConcept` requirements.
  62 * `ForwardRange`'s value type is the same type as `Value`.
  63
  64 [*For the predicate versions:]
  65
  66 * `ForwardRange` is a model of the __forward_range__ Concept.
  67 * `SortPredicate` is a model of the `StrictWeakOrderingConcept`.
  68 * `ForwardRange`'s value type is the same as `Value`.
  69 * `ForwardRange`'s value type is convertible to both of `SortPredicate`'s argument types.
  70
  71 [heading Precondition:]
  72
  73 For the non-predicate versions: `rng` is ordered in ascending order according to `operator<`.
  74
  75 For the predicate versions: `rng` is ordered in ascending order according to `pred`.
  76
  77 [heading Complexity]
  78
  79 For random-access ranges, the complexity is `O(log N)`, otherwise the complexity is `O(N)`.
  80
  81 [endsect]
  82
  83