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rippled/beast/module/core/containers/ArrayAllocationBase.h
2015-02-02 17:01:18 -08:00

136 lines
4.7 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
Portions of this file are from JUCE.
Copyright (c) 2013 - Raw Material Software Ltd.
Please visit http://www.juce.com
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.
*/
//==============================================================================
#ifndef BEAST_MODULE_CORE_CONTAINERS_ARRAYALLOCATIONBASE_H_INCLUDED
#define BEAST_MODULE_CORE_CONTAINERS_ARRAYALLOCATIONBASE_H_INCLUDED
#include <beast/HeapBlock.h>
namespace beast {
//==============================================================================
/**
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, SharedObjectArray
*/
template <class ElementType, class TypeOfCriticalSectionToUse>
class ArrayAllocationBase
: public TypeOfCriticalSectionToUse
{
public:
//==============================================================================
/** Creates an empty array. */
ArrayAllocationBase() noexcept
: numAllocated (0)
{
}
/** Destructor. */
~ArrayAllocationBase() noexcept
{
}
#if BEAST_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.reallocate ((size_t) numElements);
else
elements.free_up();
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);
bassert (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;
};
} // beast
#endif // BEAST_ARRAYALLOCATIONBASE_H_INCLUDED