gecko-dev/parser/html/jArray.h

/*
 * Copyright (c) 2008-2015 Mozilla Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#ifndef jArray_h
#define jArray_h

#include "mozilla/Attributes.h"
#include "mozilla/BinarySearch.h"
#include "nsDebug.h"

template <class T, class L>
struct staticJArray {
  const T* arr;
  const L length;
  operator T*() { return arr; }
  T& operator[](L const index) {
    MOZ_ASSERT(index >= 0, "Array access with negative index.");
    MOZ_ASSERT(index < length, "Array index out of bounds.");
    return ((T*)arr)[index];
  }
  L binarySearch(T const elem) {
    size_t idx;
    bool found = mozilla::BinarySearch(arr, 0, length, elem, &idx);
    return found ? idx : -1;
  }
};

template <class T, class L>
class autoJArray;

template <class T, class L>
class jArray {
  friend class autoJArray<T, L>;

 private:
  T* arr;

 public:
  L length;
  static jArray<T, L> newJArray(L const len) {
    MOZ_ASSERT(len >= 0, "Negative length.");
    jArray<T, L> newArray = {new T[size_t(len)], len};
    return newArray;
  }
  static jArray<T, L> newFallibleJArray(L const len) {
    MOZ_ASSERT(len >= 0, "Negative length.");
    T* a = new (mozilla::fallible) T[size_t(len)];
    jArray<T, L> newArray = {a, a ? len : 0};
    return newArray;
  }
  operator T*() { return arr; }
  T& operator[](L const index) {
    MOZ_ASSERT(index >= 0, "Array access with negative index.");
    MOZ_ASSERT(index < length, "Array index out of bounds.");
    return arr[index];
  }
  void operator=(staticJArray<T, L>& other) {
    arr = (T*)other.arr;
    length = other.length;
  }
  MOZ_IMPLICIT jArray(decltype(nullptr)) : arr(nullptr), length(0) {}
  jArray() : arr(nullptr), length(0) {}

 private:
  jArray(T* aArr, L aLength) : arr(aArr), length(aLength) {}
};

template <class T, class L>
class autoJArray {
 private:
  T* arr;

 public:
  L length;
  autoJArray() : arr(0), length(0) {}
  MOZ_IMPLICIT autoJArray(const jArray<T, L>& other)
      : arr(other.arr), length(other.length) {}
  ~autoJArray() { delete[] arr; }
  operator T*() { return arr; }
  T& operator[](L const index) {
    MOZ_ASSERT(index >= 0, "Array access with negative index.");
    MOZ_ASSERT(index < length, "Array index out of bounds.");
    return arr[index];
  }
  operator jArray<T, L>() {
    // WARNING! This makes it possible to goof with buffer ownership!
    // This is needed for the getStack and getListOfActiveFormattingElements
    // methods to work sensibly.
    jArray<T, L> newArray = {arr, length};
    return newArray;
  }
  void operator=(const jArray<T, L>& other) {
    delete[] arr;
    arr = other.arr;
    length = other.length;
  }
  void operator=(decltype(nullptr)) {
    // Make assigning null to an array in Java delete the buffer in C++
    delete[] arr;
    arr = nullptr;
    length = 0;
  }
};

#endif  // jArray_h