src/Util/ReusableArray.hpp

   1 /*
   2  * Copyright (C) 2010 Max Kellermann <max@duempel.org>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * - Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * - Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the
  14  * distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  19  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  20  * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  23  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  25  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  27  * OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #ifndef XCSOAR_REUSABLE_ARRAY_HPP
  31 #define XCSOAR_REUSABLE_ARRAY_HPP
  32
  33 #include "Util/AllocatedArray.hpp"
  34
  35 template<class T>
  36 class ReusableArray {
  37 public:
  38   typedef typename AllocatedArray<T>::size_type size_type;
  39
  40 protected:
  41   AllocatedArray<T> array;
  42
  43 public:
  44   ReusableArray() = default;
  45
  46   constexpr
  47   ReusableArray(size_type _length):array(_length) {}
  48
  49   ReusableArray(ReusableArray<T> &&other)
  50     :array(std::move(other.array)) {}
  51
  52   ReusableArray<T> &operator=(ReusableArray<T> &&other) {
  53     array = std::move(other.array);
  54     return *this;
  55   }
  56
  57   /**
  58    * Obtains an array.  Its values are undefined.
  59    */
  60   T *get(size_type _length) {
  61     array.GrowDiscard(_length);
  62     return array.begin();
  63   }
  64
  65   /**
  66    * Grows an existing array, preserving data.
  67    */
  68   T *grow(size_type old_length, size_type new_length) {
  69     array.grow_preserve(new_length, old_length);
  70     return array.begin();
  71   }
  72 };
  73
  74 #endif