Quelle EnumeratedRange.h Sprache: C

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Iterator over contiguous enum values */

/*
* Implements generator functions that create a range to iterate over the values
* of a scoped or unscoped enum. Unlike IntegerRange, which can only function on
* the underlying integral type, the elements of the generated sequence will
* have the type of the enum in question.
*
* Note that the enum values should be contiguous in the iterated range;
* unfortunately there exists no way for EnumeratedRange to enforce this
* either dynamically or at compile time.
*/

#ifndef mozilla_EnumeratedRange_h
#define mozilla_EnumeratedRange_h

#include <limits>
#include <type_traits>

#include "mozilla/Assertions.h"
#include "mozilla/ReverseIterator.h"

namespace mozilla {

namespace detail {

template <typename EnumTypeT>
class EnumeratedIterator {
public:
  typedef typename std::underlying_type<EnumTypeT>::type IntTypeT;

  template <typename EnumType>
  constexpr explicit EnumeratedIterator(EnumType aCurrent)
      : mCurrent(aCurrent) {}

  template <typename EnumType>
  explicit EnumeratedIterator(const EnumeratedIterator<EnumType>& aOther)
      : mCurrent(aOther.mCurrent) {}

  EnumTypeT operator*() const { return mCurrent; }

  /* Increment and decrement operators */

  EnumeratedIterator& operator++() {
    mCurrent = EnumTypeT(IntTypeT(mCurrent) + IntTypeT(1));
    return *this;
  }
  EnumeratedIterator& operator--() {
    mCurrent = EnumTypeT(IntTypeT(mCurrent) - IntTypeT(1));
    return *this;
  }
  EnumeratedIterator operator++(int) {
    auto ret = *this;
    mCurrent = EnumTypeT(IntTypeT(mCurrent) + IntTypeT(1));
    return ret;
  }
  EnumeratedIterator operator--(int) {
    auto ret = *this;
    mCurrent = EnumTypeT(IntTypeT(mCurrent) - IntTypeT(1));
    return ret;
  }

  /* Comparison operators */

  template <typename EnumType>
  friend bool operator==(const EnumeratedIterator<EnumType>& aIter1,
                         const EnumeratedIterator<EnumType>& aIter2);
  template <typename EnumType>
  friend bool operator!=(const EnumeratedIterator<EnumType>& aIter1,
                         const EnumeratedIterator<EnumType>& aIter2);
  template <typename EnumType>
  friend bool operator<(const EnumeratedIterator<EnumType>& aIter1,
                        const EnumeratedIterator<EnumType>& aIter2);
  template <typename EnumType>
  friend bool operator<=(const EnumeratedIterator<EnumType>& aIter1,
                         const EnumeratedIterator<EnumType>& aIter2);
  template <typename EnumType>
  friend bool operator>(const EnumeratedIterator<EnumType>& aIter1,
                        const EnumeratedIterator<EnumType>& aIter2);
  template <typename EnumType>
  friend bool operator>=(const EnumeratedIterator<EnumType>& aIter1,
                         const EnumeratedIterator<EnumType>& aIter2);

private:
  EnumTypeT mCurrent;
};

template <typename EnumType>
bool operator==(const EnumeratedIterator<EnumType>& aIter1,
                const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent == aIter2.mCurrent;
}

template <typename EnumType>
bool operator!=(const EnumeratedIterator<EnumType>& aIter1,
                const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent != aIter2.mCurrent;
}

template <typename EnumType>
bool operator<(const EnumeratedIterator<EnumType>& aIter1,
               const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent < aIter2.mCurrent;
}

template <typename EnumType>
bool operator<=(const EnumeratedIterator<EnumType>& aIter1,
                const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent <= aIter2.mCurrent;
}

template <typename EnumType>
bool operator>(const EnumeratedIterator<EnumType>& aIter1,
               const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent > aIter2.mCurrent;
}

template <typename EnumType>
bool operator>=(const EnumeratedIterator<EnumType>& aIter1,
                const EnumeratedIterator<EnumType>& aIter2) {
  return aIter1.mCurrent >= aIter2.mCurrent;
}

template <typename EnumTypeT>
class EnumeratedRange {
public:
  typedef EnumeratedIterator<EnumTypeT> iterator;
  typedef EnumeratedIterator<EnumTypeT> const_iterator;
  typedef ReverseIterator<iterator> reverse_iterator;
  typedef ReverseIterator<const_iterator> const_reverse_iterator;

  template <typename EnumType>
  constexpr EnumeratedRange(EnumType aBegin, EnumType aEnd)
      : mBegin(aBegin), mEnd(aEnd) {}

  iterator begin() const { return iterator(mBegin); }
  const_iterator cbegin() const { return begin(); }
  iterator end() const { return iterator(mEnd); }
  const_iterator cend() const { return end(); }
  reverse_iterator rbegin() const { return reverse_iterator(mEnd); }
  const_reverse_iterator crbegin() const { return rbegin(); }
  reverse_iterator rend() const { return reverse_iterator(mBegin); }
  const_reverse_iterator crend() const { return rend(); }

private:
  EnumTypeT mBegin;
  EnumTypeT mEnd;
};

}  // namespace detail

#ifdef __GNUC__
// Enums can have an unsigned underlying type, which makes some of the
// comparisons below always true or always false. Temporarily disable
// -Wtype-limits to avoid breaking -Werror builds.
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wtype-limits"
#endif

// Create a range to iterate from aBegin to aEnd, exclusive.
template <typename EnumType>
constexpr detail::EnumeratedRange<EnumType> MakeEnumeratedRange(EnumType aBegin,
                                                                EnumType aEnd) {
  MOZ_ASSERT(aBegin <= aEnd, "Cannot generate invalid, unbounded range!");
  return detail::EnumeratedRange<EnumType>(aBegin, aEnd);
}

// Create a range to iterate from EnumType(0) to aEnd, exclusive. EnumType(0)
// should exist, but note that there is no way for us to ensure that it does!
template <typename EnumType>
constexpr detail::EnumeratedRange<EnumType> MakeEnumeratedRange(EnumType aEnd) {
  return MakeEnumeratedRange(EnumType(0), aEnd);
}

// Create a range to iterate from aBegin to aEnd, inclusive.
//
// NOTE: This internally constructs a value that is one past `aEnd`, so the
// enumeration needs to either have a fixed underlying type, or `aEnd + 1` must
// be inside the range of the enumeration, in order to not be undefined
// behavior.
//
// See bug 1614512.
template <typename EnumType>
constexpr detail::EnumeratedRange<EnumType> MakeInclusiveEnumeratedRange(
    EnumType aBegin, EnumType aEnd) {
  using EnumUnderlyingType = typename std::underlying_type_t<EnumType>;
  const auto end = static_cast<EnumUnderlyingType>(aEnd);

  MOZ_ASSERT(end != std::numeric_limits<EnumUnderlyingType>::max(),
             "aEnd shouldn't overflow!");
  return MakeEnumeratedRange(aBegin, static_cast<EnumType>(end + 1));
}

template <typename EnumType>
constexpr auto MakeInclusiveEnumeratedRange(EnumType aEnd) {
  return MakeInclusiveEnumeratedRange(EnumType{0}, aEnd);
}

#ifdef __GNUC__
#  pragma GCC diagnostic pop
#endif

}  // namespace mozilla

#endif  // mozilla_EnumeratedRange_h

quality100%

¤ Dauer der Verarbeitung: 0.12 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.