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/*
==============================================================================
This file is part of the JUCE framework.
Copyright (c) Raw Material Software Limited
JUCE is an open source framework subject to commercial or open source
licensing.
By downloading, installing, or using the JUCE framework, or combining the
JUCE framework with any other source code, object code, content or any other
copyrightable work, you agree to the terms of the JUCE End User Licence
Agreement, and all incorporated terms including the JUCE Privacy Policy and
the JUCE Website Terms of Service, as applicable, which will bind you. If you
do not agree to the terms of these agreements, we will not license the JUCE
framework to you, and you must discontinue the installation or download
process and cease use of the JUCE framework.
JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
JUCE Privacy Policy: https://juce.com/juce-privacy-policy
JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/
Or:
You may also use this code under the terms of the AGPLv3:
https://www.gnu.org/licenses/agpl-3.0.en.html
THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
==============================================================================
*/
namespace juce
{
/** @cond */
/** This is an internal helper class which converts a juce ElementComparator style
class (using a "compareElements" method) into a class that's compatible with
std::sort (i.e. using an operator() to compare the elements)
@tags{Core}
*/
template <typename ElementComparator>
struct SortFunctionConverter
{
SortFunctionConverter (ElementComparator& e) : comparator (e) {}
SortFunctionConverter (const SortFunctionConverter&) = default;
template <typename Type>
bool operator() (Type a, Type b) { return comparator.compareElements (a, b) < 0; }
private:
ElementComparator& comparator;
SortFunctionConverter& operator= (const SortFunctionConverter&) = delete;
};
/** @endcond */
//==============================================================================
/**
Sorts a range of elements in an array.
The comparator object that is passed-in must define a public method with the following
signature:
@code
int compareElements (ElementType first, ElementType second);
@endcode
..and this method must return:
- a value of < 0 if the first comes before the second
- a value of 0 if the two objects are equivalent
- a value of > 0 if the second comes before the first
To improve performance, the compareElements() method can be declared as static or const.
@param comparator an object which defines a compareElements() method
@param array the array to sort
@param firstElement the index of the first element of the range to be sorted
@param lastElement the index of the last element in the range that needs
sorting (this is inclusive)
@param retainOrderOfEquivalentItems if true, the order of items that the
comparator deems the same will be maintained - this will be
a slower algorithm than if they are allowed to be moved around.
@see sortArrayRetainingOrder
*/
template <class ElementType, class ElementComparator>
static void sortArray (ElementComparator& comparator,
ElementType* const array,
int firstElement,
int lastElement,
const bool retainOrderOfEquivalentItems)
{
jassert (firstElement >= 0);
if (lastElement > firstElement)
{
SortFunctionConverter<ElementComparator> converter (comparator);
if (retainOrderOfEquivalentItems)
std::stable_sort (array + firstElement, array + lastElement + 1, converter);
else
std::sort (array + firstElement, array + lastElement + 1, converter);
}
}
//==============================================================================
/**
Searches a sorted array of elements, looking for the index at which a specified value
should be inserted for it to be in the correct order.
The comparator object that is passed-in must define a public method with the following
signature:
@code
int compareElements (ElementType first, ElementType second);
@endcode
..and this method must return:
- a value of < 0 if the first comes before the second
- a value of 0 if the two objects are equivalent
- a value of > 0 if the second comes before the first
To improve performance, the compareElements() method can be declared as static or const.
@param comparator an object which defines a compareElements() method
@param array the array to search
@param newElement the value that is going to be inserted
@param firstElement the index of the first element to search
@param lastElement the index of the last element in the range (this is non-inclusive)
*/
template <class ElementType, class ElementComparator>
static int findInsertIndexInSortedArray ([[maybe_unused]] ElementComparator& comparator,
ElementType* const array,
const ElementType newElement,
int firstElement,
int lastElement)
{
jassert (firstElement <= lastElement);
while (firstElement < lastElement)
{
if (comparator.compareElements (newElement, array [firstElement]) == 0)
{
++firstElement;
break;
}
else
{
const int halfway = (firstElement + lastElement) >> 1;
if (halfway == firstElement)
{
if (comparator.compareElements (newElement, array [halfway]) >= 0)
++firstElement;
break;
}
else if (comparator.compareElements (newElement, array [halfway]) >= 0)
{
firstElement = halfway;
}
else
{
lastElement = halfway;
}
}
}
return firstElement;
}
//==============================================================================
/**
A simple ElementComparator class that can be used to sort an array of
objects that support the '<' operator.
This will work for primitive types and objects that implement operator<().
Example: @code
Array<int> myArray;
DefaultElementComparator<int> sorter;
myArray.sort (sorter);
@endcode
@see ElementComparator
@tags{Core}
*/
template <class ElementType>
class DefaultElementComparator
{
private:
using ParameterType = typename TypeHelpers::ParameterType<ElementType>::type;
public:
static int compareElements (ParameterType first, ParameterType second)
{
return (first < second) ? -1 : ((second < first) ? 1 : 0);
}
};
} // namespace juce
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