juce_ElementComparator.h

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/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. 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.
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
#ifndef DOXYGEN

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;
};
 
#endif
 
 
//==============================================================================
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);
    }
}
 
 
//==============================================================================
template <class ElementType, class ElementComparator>
static int findInsertIndexInSortedArray (ElementComparator& comparator,
                                         ElementType* const array,
                                         const ElementType newElement,
                                         int firstElement,
                                         int lastElement)
{
    jassert (firstElement <= lastElement);
 
    ignoreUnused (comparator); // if you pass in an object with a static compareElements() method, this
                               // avoids getting warning messages about the parameter being unused
 
    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;
}
 
//==============================================================================
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