From b75c82f6456edbc00646da15531cfb63f8957817 Mon Sep 17 00:00:00 2001
From: Karsten Heimrich <karsten.heimrich@qt.io>
Date: Tue, 7 Apr 2020 12:34:24 +0200
Subject: Resolve Qt6 TODO items, replace Median and BlockSizeManager

* Replaces the, only internaly used, implementation of template
  class Median with a fixed size none templated version.
* Replaces BlockSizeManager with an updated BlockSizeManager V2,
  but keeping the original name.
* adapt the auto-test to take the fixed size array into account

Change-Id: If76cb944676c4a06a7566ad0bc37ded25b81c70c
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
---
 src/concurrent/qtconcurrentmedian.h | 83 ++-----------------------------------
 1 file changed, 3 insertions(+), 80 deletions(-)

(limited to 'src/concurrent/qtconcurrentmedian.h')

diff --git a/src/concurrent/qtconcurrentmedian.h b/src/concurrent/qtconcurrentmedian.h
index cec2431d6f..aab80794d9 100644
--- a/src/concurrent/qtconcurrentmedian.h
+++ b/src/concurrent/qtconcurrentmedian.h
@@ -42,97 +42,21 @@
 
 #include <QtConcurrent/qtconcurrent_global.h>
 
-#if !defined(QT_NO_CONCURRENT) ||defined(Q_CLANG_QDOC)
-
-#include <QtCore/qvector.h>
+#if !defined(QT_NO_CONCURRENT) || defined(Q_CLANG_QDOC)
 
 #include <algorithm>
+#include <cstring>
 
 QT_BEGIN_NAMESPACE
 
-
-
 namespace QtConcurrent {
 
-template <typename T>
 class Median
 {
-public:
-    Median(int _bufferSize)
-        : currentMedian(), bufferSize(_bufferSize), currentIndex(0), valid(false), dirty(true)
-    {
-        values.resize(bufferSize);
-    }
-
-    void reset()
-    {
-        values.fill(0);
-        currentIndex = 0;
-        valid = false;
-        dirty = true;
-    }
-
-    void addValue(T value)
-    {
-        currentIndex = ((currentIndex + 1) % bufferSize);
-        if (valid == false && currentIndex % bufferSize == 0)
-            valid = true;
-
-        // Only update the cached median value when we have to, that
-        // is when the new value is on then other side of the median
-        // compared to the current value at the index.
-        const T currentIndexValue = values[currentIndex];
-        if ((currentIndexValue > currentMedian && currentMedian > value)
-            || (currentMedian > currentIndexValue && value > currentMedian)) {
-            dirty = true;
-        }
-
-        values[currentIndex] = value;
-    }
-
-    bool isMedianValid() const
-    {
-        return valid;
-    }
-
-    T median()
-    {
-        if (dirty) {
-            dirty = false;
-
-// This is a workaround for http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58800
-// Avoid using std::nth_element for the affected stdlibc++ releases 4.7.3 and 4.8.2.
-// Note that the official __GLIBCXX__ value of the releases is not used since that
-// one might be patched on some GNU/Linux distributions.
-#if defined(__GLIBCXX__) && __GLIBCXX__ <= 20140107
-            QVector<T> sorted = values;
-            std::sort(sorted.begin(), sorted.end());
-            currentMedian = sorted.at(bufferSize / 2);
-#else
-            QVector<T> copy = values;
-            typename QVector<T>::iterator begin = copy.begin(), mid = copy.begin() + bufferSize/2, end = copy.end();
-            std::nth_element(begin, mid, end);
-            currentMedian = *mid;
-#endif
-        }
-        return currentMedian;
-    }
-private:
-    QVector<T> values;
-    T currentMedian;
-    int bufferSize;
-    int currentIndex;
-    bool valid;
-    bool dirty;
-};
-
-// ### Qt6: Drop Median<double> in favor of this faster MedianDouble
-class MedianDouble
-{
 public:
     enum { BufferSize = 7 };
 
-    MedianDouble()
+    Median()
         : currentMedian(), currentIndex(0), valid(false), dirty(true)
     {
         std::fill_n(values, static_cast<int>(BufferSize), 0.0);
@@ -195,7 +119,6 @@ private:
 
 } // namespace QtConcurrent
 
-
 QT_END_NAMESPACE
 
 #endif // QT_NO_CONCURRENT
-- 
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