JUCE/modules/juce_core/containers/juce_ArrayAllocationBase.h

/*
  ==============================================================================

   This file is part of the juce_core module of the JUCE library.
   Copyright (c) 2013 - Raw Material Software Ltd.

   Permission to use, copy, modify, and/or distribute this software for any purpose with
   or without fee is hereby granted, provided that the above copyright notice and this
   permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN
   NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
   DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
   IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ------------------------------------------------------------------------------

   NOTE! This permissive ISC license applies ONLY to files within the juce_core module!
   All other JUCE modules are covered by a dual GPL/commercial license, so if you are
   using any other modules, be sure to check that you also comply with their license.

   For more details, visit www.juce.com

  ==============================================================================
*/

#ifndef JUCE_ARRAYALLOCATIONBASE_H_INCLUDED
#define JUCE_ARRAYALLOCATIONBASE_H_INCLUDED

#include "../memory/juce_HeapBlock.h"


//==============================================================================
/**
    Implements some basic array storage allocation functions.

    This class isn't really for public use - it's used by the other
    array classes, but might come in handy for some purposes.

    It inherits from a critical section class to allow the arrays to use
    the "empty base class optimisation" pattern to reduce their footprint.

    @see Array, OwnedArray, ReferenceCountedArray
*/
template <class ElementType, class TypeOfCriticalSectionToUse>
class ArrayAllocationBase  : public TypeOfCriticalSectionToUse
{
public:
    //==============================================================================
    /** Creates an empty array. */
    ArrayAllocationBase() noexcept
        : numAllocated (0)
    {
    }

    /** Destructor. */
    ~ArrayAllocationBase() noexcept
    {
    }

   #if JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS
    ArrayAllocationBase (ArrayAllocationBase<ElementType, TypeOfCriticalSectionToUse>&& other) noexcept
        : elements (static_cast <HeapBlock <ElementType>&&> (other.elements)),
          numAllocated (other.numAllocated)
    {
    }

    ArrayAllocationBase& operator= (ArrayAllocationBase<ElementType, TypeOfCriticalSectionToUse>&& other) noexcept
    {
        elements = static_cast <HeapBlock <ElementType>&&> (other.elements);
        numAllocated = other.numAllocated;
        return *this;
    }
   #endif

    //==============================================================================
    /** Changes the amount of storage allocated.

        This will retain any data currently held in the array, and either add or
        remove extra space at the end.

        @param numElements  the number of elements that are needed
    */
    void setAllocatedSize (const int numElements)
    {
        if (numAllocated != numElements)
        {
            if (numElements > 0)
                elements.realloc ((size_t) numElements);
            else
                elements.free();

            numAllocated = numElements;
        }
    }

    /** Increases the amount of storage allocated if it is less than a given amount.

        This will retain any data currently held in the array, but will add
        extra space at the end to make sure there it's at least as big as the size
        passed in. If it's already bigger, no action is taken.

        @param minNumElements  the minimum number of elements that are needed
    */
    void ensureAllocatedSize (const int minNumElements)
    {
        if (minNumElements > numAllocated)
            setAllocatedSize ((minNumElements + minNumElements / 2 + 8) & ~7);

        jassert (numAllocated <= 0 || elements != nullptr);
    }

    /** Minimises the amount of storage allocated so that it's no more than
        the given number of elements.
    */
    void shrinkToNoMoreThan (const int maxNumElements)
    {
        if (maxNumElements < numAllocated)
            setAllocatedSize (maxNumElements);
    }

    /** Swap the contents of two objects. */
    void swapWith (ArrayAllocationBase <ElementType, TypeOfCriticalSectionToUse>& other) noexcept
    {
        elements.swapWith (other.elements);
        std::swap (numAllocated, other.numAllocated);
    }

    //==============================================================================
    HeapBlock <ElementType> elements;
    int numAllocated;

private:
    JUCE_DECLARE_NON_COPYABLE (ArrayAllocationBase)
};


#endif   // JUCE_ARRAYALLOCATIONBASE_H_INCLUDED