Minor performance improvements

Author: Eugene Kazaev

ChatLayout.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'ChatLayout'
-  s.version          = '1.1.12'
+  s.version          = '1.1.13'
   s.summary          = 'Chat UI Library. It uses custom UICollectionViewLayout to provide you full control over the presentation.'
   s.swift_version    = '5.2'
 

ChatLayout/Classes/Core/Model/StateController.swift

@@ -633,11 +633,10 @@ final class StateController {
 
                 var startingIndex = 0
                 // If header is not visible
-                if traverseState == .notFound {
-                    // Find if any of the items of the section is visible
-                    if let firstMatchIndex = Array(section.items.enumerated()).binarySearch(predicate: { itemIndex, _ in
+                if traverseState == .notFound, !section.items.isEmpty {
+                    func predicate(itemIndex: Int) -> ComparisonResult {
                         let itemPath = ItemPath(item: itemIndex, section: sectionIndex)
-                        guard let itemFrame = self.itemFrame(for: itemPath, kind: .cell, at: state, isFinal: true) else {
+                        guard let itemFrame = itemFrame(for: itemPath, kind: .cell, at: state, isFinal: true) else {
                             return .orderedDescending
                         }
                         if itemFrame.intersects(visibleRect) {
@@ -647,7 +646,11 @@ final class StateController {
                             return .orderedDescending
                         }
                         return .orderedAscending
-                    }) {
+                    }
+
+                    // Find if any of the items of the section is visible
+                    if [ComparisonResult.orderedSame, .orderedDescending].contains(predicate(itemIndex: section.items.count - 1)),
+                       let firstMatchIndex = Array(0...section.items.count - 1).binarySearch(predicate: predicate) {
                         // Find first item that is visible
                         startingIndex = firstMatchIndex
                         for itemIndex in (0..<firstMatchIndex).reversed() {
@@ -662,7 +665,7 @@ final class StateController {
                         }
                     } else {
                         // Otherwise we can safely skip all the items in the section and go to footer.
-                        startingIndex = section.items.count - 1
+                        startingIndex = section.items.count
                     }
                 }
 

Example/Podfile.lock

@@ -1,10 +1,10 @@
 PODS:
-  - ChatLayout (1.1.12):
-    - ChatLayout/Ultimate (= 1.1.12)
-  - ChatLayout/Core (1.1.12)
-  - ChatLayout/Extras (1.1.12):
+  - ChatLayout (1.1.13):
+    - ChatLayout/Ultimate (= 1.1.13)
+  - ChatLayout/Core (1.1.13)
+  - ChatLayout/Extras (1.1.13):
     - ChatLayout/Core
-  - ChatLayout/Ultimate (1.1.12):
+  - ChatLayout/Ultimate (1.1.13):
     - ChatLayout/Core
     - ChatLayout/Extras
   - DifferenceKit (1.2.0):
@@ -35,7 +35,7 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  ChatLayout: 8f41f556773cc215fad67a1064ec40badcd99c83
+  ChatLayout: 3043e079e1b2e46239fc2f33bcbd3e679f1314cc
   DifferenceKit: 5659c430bb7fe45876fa32ce5cba5d6167f0c805
   FPSCounter: 884afec377de66637808c4f52ecc3b85a404732b
   InputBarAccessoryView: 74d471ab1fa1736806be50328df79257e52865a9