mfbt/Array.h
author Geoff Brown <gbrown@mozilla.com>
Mon, 06 May 2019 18:53:55 +0000
changeset 472757 7a580c406283099dae7a2abcc483e16f17d6d51f
parent 466932 a01e770ef4f534b9ab9989be2080be0c59e6cbda
permissions -rw-r--r--
Bug 1545226 - Enable some android gtests in netwerk/test/gtest/parse-ftp; r=jmaher With changes from bug 1548555, one of the gtests previously disabled on Android can be re-enabled, but most of the tests in netwerk/test/gtest are still problematic (some won't build for me). Differential Revision: https://phabricator.services.mozilla.com/D30081

/* -*- 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/. */

/* A compile-time constant-length array with bounds-checking assertions. */

#ifndef mozilla_Array_h
#define mozilla_Array_h

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

#include <ostream>
#include <stddef.h>

namespace mozilla {

template <typename T, size_t Length>
class Array {
  T mArr[Length];

 public:
  Array() {}

  template <typename... Args>
  MOZ_IMPLICIT constexpr Array(Args&&... aArgs)
      : mArr{std::forward<Args>(aArgs)...} {
    static_assert(sizeof...(aArgs) == Length,
                  "The number of arguments should be equal to the template "
                  "parameter Length");
  }

  T& operator[](size_t aIndex) {
    MOZ_ASSERT(aIndex < Length);
    return mArr[aIndex];
  }

  const T& operator[](size_t aIndex) const {
    MOZ_ASSERT(aIndex < Length);
    return mArr[aIndex];
  }

  bool operator==(const Array<T, Length>& aOther) const {
    for (size_t i = 0; i < Length; i++) {
      if (mArr[i] != aOther[i]) {
        return false;
      }
    }
    return true;
  }

  typedef T* iterator;
  typedef const T* const_iterator;
  typedef ReverseIterator<T*> reverse_iterator;
  typedef ReverseIterator<const T*> const_reverse_iterator;

  // Methods for range-based for loops.
  iterator begin() { return mArr; }
  const_iterator begin() const { return mArr; }
  const_iterator cbegin() const { return begin(); }
  iterator end() { return mArr + Length; }
  const_iterator end() const { return mArr + Length; }
  const_iterator cend() const { return end(); }

  // Methods for reverse iterating.
  reverse_iterator rbegin() { return reverse_iterator(end()); }
  const_reverse_iterator rbegin() const {
    return const_reverse_iterator(end());
  }
  const_reverse_iterator crbegin() const { return rbegin(); }
  reverse_iterator rend() { return reverse_iterator(begin()); }
  const_reverse_iterator rend() const {
    return const_reverse_iterator(begin());
  }
  const_reverse_iterator crend() const { return rend(); }
};

template <typename T>
class Array<T, 0> {
 public:
  T& operator[](size_t aIndex) { MOZ_CRASH("indexing into zero-length array"); }

  const T& operator[](size_t aIndex) const {
    MOZ_CRASH("indexing into zero-length array");
  }
};

// MOZ_DBG support

template <typename T, size_t Length>
std::ostream& operator<<(std::ostream& aOut, const Array<T, Length>& aArray) {
  return aOut << MakeSpan(aArray);
}

} /* namespace mozilla */

#endif /* mozilla_Array_h */