130 lines
4.2 KiB
C++
130 lines
4.2 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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Implements some basic array storage allocation functions.
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This class isn't really for public use - it's used by the other
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array classes, but might come in handy for some purposes.
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It inherits from a critical section class to allow the arrays to use
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the "empty base class optimisation" pattern to reduce their footprint.
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@see Array, OwnedArray, ReferenceCountedArray
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@tags{Core}
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*/
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template <class ElementType, class TypeOfCriticalSectionToUse>
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class ArrayAllocationBase : public TypeOfCriticalSectionToUse
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{
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public:
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//==============================================================================
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/** Creates an empty array. */
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ArrayAllocationBase() noexcept
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{
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}
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/** Destructor. */
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~ArrayAllocationBase() noexcept
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{
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}
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ArrayAllocationBase (ArrayAllocationBase&& other) noexcept
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: elements (static_cast<HeapBlock<ElementType>&&> (other.elements)),
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numAllocated (other.numAllocated)
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{
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}
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ArrayAllocationBase& operator= (ArrayAllocationBase&& other) noexcept
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{
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elements = static_cast<HeapBlock<ElementType>&&> (other.elements);
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numAllocated = other.numAllocated;
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return *this;
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}
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//==============================================================================
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/** Changes the amount of storage allocated.
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This will retain any data currently held in the array, and either add or
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remove extra space at the end.
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@param numElements the number of elements that are needed
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*/
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void setAllocatedSize (int numElements)
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{
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if (numAllocated != numElements)
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{
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if (numElements > 0)
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elements.realloc ((size_t) numElements);
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else
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elements.free();
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numAllocated = numElements;
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}
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}
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/** Increases the amount of storage allocated if it is less than a given amount.
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This will retain any data currently held in the array, but will add
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extra space at the end to make sure there it's at least as big as the size
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passed in. If it's already bigger, no action is taken.
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@param minNumElements the minimum number of elements that are needed
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*/
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void ensureAllocatedSize (int minNumElements)
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{
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if (minNumElements > numAllocated)
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setAllocatedSize ((minNumElements + minNumElements / 2 + 8) & ~7);
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jassert (numAllocated <= 0 || elements != nullptr);
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}
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/** Minimises the amount of storage allocated so that it's no more than
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the given number of elements.
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*/
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void shrinkToNoMoreThan (int maxNumElements)
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{
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if (maxNumElements < numAllocated)
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setAllocatedSize (maxNumElements);
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}
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/** Swap the contents of two objects. */
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void swapWith (ArrayAllocationBase& other) noexcept
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{
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elements.swapWith (other.elements);
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std::swap (numAllocated, other.numAllocated);
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}
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//==============================================================================
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HeapBlock<ElementType> elements;
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int numAllocated = 0;
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private:
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JUCE_DECLARE_NON_COPYABLE (ArrayAllocationBase)
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};
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} // namespace juce
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