Migrating to built-in algorithms (#3892)

Author: jjatie

Source/Charts/Charts/ChartViewBase.swift

@@ -402,7 +402,7 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
     /// - Returns: `true` if there are values to highlight, `false` ifthere are no values to highlight.
     @objc open func valuesToHighlight() -> Bool
     {
-        return _indicesToHighlight.count > 0
+        return !_indicesToHighlight.isEmpty
     }
 
     /// Highlights the values at the given indices in the given DataSets. Provide

Source/Charts/Charts/PieChartView.swift

@@ -191,17 +191,12 @@ open class PieChartView: PieRadarChartViewBase
         _absoluteAngles.reserveCapacity(entryCount)
 
         let yValueSum = (_data as! PieChartData).yValueSum
-        
-        var dataSets = data.dataSets
 
         var cnt = 0
 
-        for i in 0 ..< data.dataSetCount
+        for set in data.dataSets
         {
-            let set = dataSets[i]
-            let entryCount = set.entryCount
-
-            for j in 0 ..< entryCount
+            for j in 0 ..< set.entryCount
             {
                 guard let e = set.entryForIndex(j) else { continue }
 
@@ -224,22 +219,7 @@ open class PieChartView: PieRadarChartViewBase
     /// Checks if the given index is set to be highlighted.
     @objc open func needsHighlight(index: Int) -> Bool
     {
-        // no highlight
-        if !valuesToHighlight()
-        {
-            return false
-        }
-        
-        for i in 0 ..< _indicesToHighlight.count
-        {
-            // check if the xvalue for the given dataset needs highlight
-            if Int(_indicesToHighlight[i].x) == index
-            {
-                return true
-            }
-        }
-        
-        return false
+        return _indicesToHighlight.contains { Int($0.x) == index }
     }
 
     /// calculates the needed angle for a given value
@@ -259,36 +239,22 @@ open class PieChartView: PieRadarChartViewBase
     {
         fatalError("PieChart has no XAxis")
     }
-    
+
     open override func indexForAngle(_ angle: CGFloat) -> Int
     {
+        // TODO: Return nil instead of -1
         // take the current angle of the chart into consideration
         let a = (angle - self.rotationAngle).normalizedAngle
-        for i in 0 ..< _absoluteAngles.count
-        {
-            if _absoluteAngles[i] > a
-            {
-                return i
-            }
-        }
-        
-        return -1 // return -1 if no index found
+        return _absoluteAngles.firstIndex { $0 > a } ?? -1
     }
 
     /// - Returns: The index of the DataSet this x-index belongs to.
     @objc open func dataSetIndexForIndex(_ xValue: Double) -> Int
     {
-        var dataSets = _data?.dataSets ?? []
-        
-        for i in 0 ..< dataSets.count
-        {
-            if (dataSets[i].entryForXValue(xValue, closestToY: Double.nan) !== nil)
-            {
-                return i
-            }
-        }
-        
-        return -1
+        // TODO: Return nil instead of -1
+        return _data?.dataSets.firstIndex {
+            $0.entryForXValue(xValue, closestToY: .nan) != nil
+        } ?? -1
     }
 
     /// - Returns: An integer array of all the different angles the chart slices

Source/Charts/Charts/RadarChartView.swift

@@ -168,21 +168,9 @@ open class RadarChartView: PieRadarChartViewBase
         let sliceAngle = self.sliceAngle
 
         let max = _data?.maxEntryCountSet?.entryCount ?? 0
-        
-        var index = 0
-        
-        for i in 0..<max
-        {
-            let referenceAngle = sliceAngle * CGFloat(i + 1) - sliceAngle / 2.0
-            
-            if referenceAngle > a
-            {
-                index = i
-                break
-            }
-        }
-        
-        return index
+        return (0..<max).firstIndex {
+            sliceAngle * CGFloat($0 + 1) - sliceAngle / 2.0 > a
+        } ?? max
     }
 
     /// The object that represents all y-labels of the RadarChart.

Source/Charts/Components/AxisBase.swift

@@ -261,14 +261,8 @@ open class AxisBase: ComponentBase
     /// Removes the specified ChartLimitLine from the axis.
     @objc open func removeLimitLine(_ line: ChartLimitLine)
     {
-        for i in 0 ..< _limitLines.count
-        {
-            if _limitLines[i] === line
-            {
-                _limitLines.remove(at: i)
-                return
-            }
-        }
+        guard let i = _limitLines.firstIndex(of: line) else { return }
+        _limitLines.remove(at: i)
     }
 
     /// Removes all LimitLines from the axis.

Source/Charts/Data/Implementations/ChartBaseDataSet.swift

@@ -253,14 +253,7 @@ open class ChartBaseDataSet: NSObject, IChartDataSet, NSCopying
     ///   - alpha: alpha to apply to the set `colors`
     @objc open func setColors(_ colors: [NSUIColor], alpha: CGFloat)
     {
-        var colorsWithAlpha = colors
-        
-        for i in 0 ..< colorsWithAlpha.count
-        {
-            colorsWithAlpha[i] = colorsWithAlpha[i] .withAlphaComponent(alpha)
-        }
-        
-        self.colors = colorsWithAlpha
+        self.colors = colors.map { $0.withAlphaComponent(alpha) }
     }
 
     /// Sets colors with a specific alpha value.
@@ -409,14 +402,9 @@ open class ChartBaseDataSet: NSObject, IChartDataSet, NSCopying
 
     open override var debugDescription: String
     {
-        var desc = description + ":"
-        
-        for i in 0 ..< self.entryCount
-        {
-            desc += "\n" + (self.entryForIndex(i)?.description ?? "")
+        return (0..<entryCount).reduce(description + ":") {
+            $0 + "\n" + (self.entryForIndex($1)?.description ?? "")
         }
-        
-        return desc
     }
 
     // MARK: - NSCopying