source/modules/juce_core/containers/juce_ArrayAllocationBase.h

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library.
   5    Copyright (c) 2022 - Raw Material Software Limited
   6
   7    JUCE is an open source library subject to commercial or open-source
   8    licensing.
   9
  10    The code included in this file is provided under the terms of the ISC license
  11    http://www.isc.org/downloads/software-support-policy/isc-license. Permission
  12    To use, copy, modify, and/or distribute this software for any purpose with or
  13    without fee is hereby granted provided that the above copyright notice and
  14    this permission notice appear in all copies.
  15
  16    JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
  17    EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
  18    DISCLAIMED.
  19
  20   ==============================================================================
  21 */
  22
  23 namespace juce
  24 {
  25
  26 //==============================================================================
  27 /**
  28     Implements some basic array storage allocation functions.
  29
  30     This class isn't really for public use - it used to be part of the
  31     container classes but has since been superseded by ArrayBase. Eventually
  32     it will be removed from the API.
  33
  34     @tags{Core}
  35 */
  36 template <class ElementType, class TypeOfCriticalSectionToUse>
  37 class ArrayAllocationBase  : public TypeOfCriticalSectionToUse
  38 {
  39 public:
  40     //==============================================================================
  41     /** Creates an empty array. */
  42     ArrayAllocationBase() = default;
  43
  44     /** Destructor. */
  45     ~ArrayAllocationBase() = default;
  46
  47     ArrayAllocationBase (ArrayAllocationBase&& other) noexcept
  48         : elements (std::move (other.elements)),
  49           numAllocated (other.numAllocated)
  50     {
  51     }
  52
  53     ArrayAllocationBase& operator= (ArrayAllocationBase&& other) noexcept
  54     {
  55         elements = std::move (other.elements);
  56         numAllocated = other.numAllocated;
  57         return *this;
  58     }
  59
  60     //==============================================================================
  61     /** Changes the amount of storage allocated.
  62
  63         This will retain any data currently held in the array, and either add or
  64         remove extra space at the end.
  65
  66         @param numElements  the number of elements that are needed
  67     */
  68     void setAllocatedSize (int numElements)
  69     {
  70         if (numAllocated != numElements)
  71         {
  72             if (numElements > 0)
  73                 elements.realloc ((size_t) numElements);
  74             else
  75                 elements.free();
  76
  77             numAllocated = numElements;
  78         }
  79     }
  80
  81     /** Increases the amount of storage allocated if it is less than a given amount.
  82
  83         This will retain any data currently held in the array, but will add
  84         extra space at the end to make sure there it's at least as big as the size
  85         passed in. If it's already bigger, no action is taken.
  86
  87         @param minNumElements  the minimum number of elements that are needed
  88     */
  89     void ensureAllocatedSize (int minNumElements)
  90     {
  91         if (minNumElements > numAllocated)
  92             setAllocatedSize ((minNumElements + minNumElements / 2 + 8) & ~7);
  93
  94         jassert (numAllocated <= 0 || elements != nullptr);
  95     }
  96
  97     /** Minimises the amount of storage allocated so that it's no more than
  98         the given number of elements.
  99     */
 100     void shrinkToNoMoreThan (int maxNumElements)
 101     {
 102         if (maxNumElements < numAllocated)
 103             setAllocatedSize (maxNumElements);
 104     }
 105
 106     /** Swap the contents of two objects. */
 107     void swapWith (ArrayAllocationBase& other) noexcept
 108     {
 109         elements.swapWith (other.elements);
 110         std::swap (numAllocated, other.numAllocated);
 111     }
 112
 113     //==============================================================================
 114     HeapBlock<ElementType> elements;
 115     int numAllocated = 0;
 116
 117 private:
 118     JUCE_DECLARE_NON_COPYABLE (ArrayAllocationBase)
 119 };
 120
 121 } // namespace juce