mfbt/Range.h
author Bryce Van Dyk <bvandyk@mozilla.com>
Mon, 27 Aug 2018 16:25:54 +0000
changeset 488616 259675bd67f96acf1ae0f2ed6115de4331a94d32
parent 398844 261772d7198542e9cf1f0577a55446785a2c189d
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1486502 - Add widevine CDM headers to third party paths, clang-format ignore. r=sylvestre We wish to keep the widevine headers in the same formatting as upstream to ease comparison and as we do not modify these files. This patch adds the existing headers, as well as another we anticipate pulling down for our next bump (content_decryption_module_proxy.h) to the ignored paths. These files are ignored individually rather than the whole directory they're in, as we also have Mozilla code in that dir. Differential Revision: https://phabricator.services.mozilla.com/D4347

/* -*- 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/. */

#ifndef mozilla_Range_h
#define mozilla_Range_h

#include "mozilla/RangedPtr.h"
#include "mozilla/TypeTraits.h"
#include "mozilla/Span.h"

#include <stddef.h>

namespace mozilla {

// Range<T> is a tuple containing a pointer and a length.
template <typename T>
class Range
{
  const RangedPtr<T> mStart;
  const RangedPtr<T> mEnd;

public:
  Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
  Range(T* aPtr, size_t aLength)
    : mStart(aPtr, aPtr, aPtr + aLength),
      mEnd(aPtr + aLength, aPtr, aPtr + aLength)
  {}
  Range(const RangedPtr<T>& aStart, const RangedPtr<T>& aEnd)
    : mStart(aStart.get(), aStart.get(), aEnd.get()),
      mEnd(aEnd.get(), aStart.get(), aEnd.get())
  {
    // Only accept two RangedPtrs within the same range.
    aStart.checkIdenticalRange(aEnd);
    MOZ_ASSERT(aStart <= aEnd);
  }

  template<typename U,
           class = typename EnableIf<IsConvertible<U (*)[], T (*)[]>::value,
                                     int>::Type>
  MOZ_IMPLICIT Range(const Range<U>& aOther)
    : mStart(aOther.mStart),
      mEnd(aOther.mEnd)
  {}

  MOZ_IMPLICIT Range(Span<T> aSpan)
    : Range(aSpan.Elements(), aSpan.Length())
  {
  }

  template<typename U,
           class = typename EnableIf<IsConvertible<U (*)[], T (*)[]>::value,
                                     int>::Type>
  MOZ_IMPLICIT Range(const Span<U>& aSpan)
    : Range(aSpan.Elements(), aSpan.Length())
  {
  }

  RangedPtr<T> begin() const { return mStart; }
  RangedPtr<T> end() const { return mEnd; }
  size_t length() const { return mEnd - mStart; }

  T& operator[](size_t aOffset) const { return mStart[aOffset]; }

  explicit operator bool() const { return mStart != nullptr; }

  operator Span<T>() { return Span<T>(mStart.get(), length()); }

  operator Span<const T>() const { return Span<T>(mStart.get(), length()); }
};

template<class T>
Span<T>
MakeSpan(Range<T>& aRange)
{
  return aRange;
}

template<class T>
Span<const T>
MakeSpan(const Range<T>& aRange)
{
  return aRange;
}

} // namespace mozilla

#endif /* mozilla_Range_h */