diff --git a/src/plugins/diffeditor/diffeditorwidget.cpp b/src/plugins/diffeditor/diffeditorwidget.cpp
index 4e9da47b97f..a4a9adc8bee 100644
--- a/src/plugins/diffeditor/diffeditorwidget.cpp
+++ b/src/plugins/diffeditor/diffeditorwidget.cpp
@@ -370,6 +370,41 @@ bool DiffEditorWidget::isEqual(const QList<Diff> &diffList, int diffNumber) cons
     return false;
 }
 
+QList<TextLineData> DiffEditorWidget::assemblyRows(const QStringList &lines,
+                                                   const QMap<int, int> &lineSpans,
+                                                   const QMap<int, int> &changedPositions,
+                                                   QMap<int, int> *outputChangedPositions) const
+{
+    QList<TextLineData> data;
+
+    int spanOffset = 0;
+    int pos = 0;
+    QMap<int, int>::ConstIterator changedIt = changedPositions.constBegin();
+    QMap<int, int>::ConstIterator changedEnd = changedPositions.constEnd();
+    const int lineCount = lines.count();
+    for (int i = 0; i <= lineCount; i++) {
+        for (int j = 0; j < lineSpans.value(i); j++) {
+            data.append(TextLineData(TextLineData::Separator));
+            spanOffset++;
+        }
+        if (i < lineCount) {
+            const int textLength = lines.at(i).count() + 1;
+            pos += textLength;
+            data.append(lines.at(i));
+        }
+        while (changedIt != changedEnd) {
+            if (changedIt.key() >= pos)
+                break;
+
+            const int startPos = changedIt.key() + spanOffset;
+            const int endPos = changedIt.value() + spanOffset;
+            if (outputChangedPositions)
+                outputChangedPositions->insert(startPos, endPos);
+            ++changedIt;
+        }
+    }
+    return data;
+}
 
 ChunkData DiffEditorWidget::calculateOriginalData(const QList<Diff> &diffList) const
 {
@@ -404,9 +439,9 @@ ChunkData DiffEditorWidget::calculateOriginalData(const QList<Diff> &diffList) c
 
         const bool equal = isEqual(diffList, i);
         if (diff.command == Diff::Insert) {
-            lastRightLineEqual = lastRightLineEqual ? equal : false;
+            lastRightLineEqual = lastRightLineEqual && equal;
         } else if (diff.command == Diff::Delete) {
-            lastLeftLineEqual = lastLeftLineEqual ? equal : false;
+            lastLeftLineEqual = lastLeftLineEqual && equal;
         }
 
         const int lastLeftPos = currentLeftPos;
@@ -428,14 +463,14 @@ ChunkData DiffEditorWidget::calculateOriginalData(const QList<Diff> &diffList) c
                     currentLeftLineOffset++;
                     leftLines.append(QString());
                     currentLeftPos++;
-                    lastLeftLineEqual = line.count() ? equal : true;
+                    lastLeftLineEqual = !line.count() || equal;
                 }
                 if (diff.command != Diff::Delete) {
                     currentRightLine++;
                     currentRightLineOffset++;
                     rightLines.append(QString());
                     currentRightPos++;
-                    lastRightLineEqual = line.count() ? equal : true;
+                    lastRightLineEqual = !line.count() || equal;
                 }
             }
 
@@ -502,69 +537,14 @@ ChunkData DiffEditorWidget::calculateOriginalData(const QList<Diff> &diffList) c
         }
     }
 
-    QList<TextLineData> leftData;
-    int spanOffset = 0;
-    int pos = 0;
-    QMap<int, int>::ConstIterator leftChangedIt = leftChangedPositions.constBegin();
-    for (int i = 0; i < leftLines.count(); i++) {
-        for (int j = 0; j < leftLineSpans.value(i); j++) {
-            leftData.append(TextLineData(TextLineData::Separator));
-            spanOffset++;
-        }
-        const int textLength = leftLines.at(i).count() + 1;
-        pos += textLength;
-        leftData.append(leftLines.at(i));
-        while (leftChangedIt != leftChangedPositions.constEnd()) {
-            if (leftChangedIt.key() >= pos)
-                break;
-
-            const int startPos = leftChangedIt.key() + spanOffset;
-            const int endPos = leftChangedIt.value() + spanOffset;
-            chunkData.changedLeftPositions.insert(startPos, endPos);
-            leftChangedIt++;
-        }
-    }
-    while (leftChangedIt != leftChangedPositions.constEnd()) {
-        if (leftChangedIt.key() >= pos)
-            break;
-
-        const int startPos = leftChangedIt.key() + spanOffset;
-        const int endPos = leftChangedIt.value() + spanOffset;
-        chunkData.changedLeftPositions.insert(startPos, endPos);
-        leftChangedIt++;
-    }
-
-    QList<TextLineData> rightData;
-    spanOffset = 0;
-    pos = 0;
-    QMap<int, int>::ConstIterator rightChangedIt = rightChangedPositions.constBegin();
-    for (int i = 0; i < rightLines.count(); i++) {
-        for (int j = 0; j < rightLineSpans.value(i); j++) {
-            rightData.append(TextLineData(TextLineData::Separator));
-            spanOffset++;
-        }
-        const int textLength = rightLines.at(i).count() + 1;
-        pos += textLength;
-        rightData.append(rightLines.at(i));
-        while (rightChangedIt != rightChangedPositions.constEnd()) {
-            if (rightChangedIt.key() >= pos)
-                break;
-
-            const int startPos = rightChangedIt.key() + spanOffset;
-            const int endPos = rightChangedIt.value() + spanOffset;
-            chunkData.changedRightPositions.insert(startPos, endPos);
-            rightChangedIt++;
-        }
-    }
-    while (rightChangedIt != rightChangedPositions.constEnd()) {
-        if (rightChangedIt.key() >= pos)
-            break;
-
-        const int startPos = rightChangedIt.key() + spanOffset;
-        const int endPos = rightChangedIt.value() + spanOffset;
-        chunkData.changedRightPositions.insert(startPos, endPos);
-        rightChangedIt++;
-    }
+    QList<TextLineData> leftData = assemblyRows(leftLines,
+                                                leftLineSpans,
+                                                leftChangedPositions,
+                                                &chunkData.changedLeftPositions);
+    QList<TextLineData> rightData = assemblyRows(rightLines,
+                                                 rightLineSpans,
+                                                 rightChangedPositions,
+                                                 &chunkData.changedRightPositions);
 
     // fill ending separators
     for (int i = leftData.count(); i < rightData.count(); i++)
diff --git a/src/plugins/diffeditor/diffeditorwidget.h b/src/plugins/diffeditor/diffeditorwidget.h
index 79a96c66854..8bd8d11f721 100644
--- a/src/plugins/diffeditor/diffeditorwidget.h
+++ b/src/plugins/diffeditor/diffeditorwidget.h
@@ -129,6 +129,10 @@ private:
             QTextCursor &cursor,
             const QMap<int, int> &positions) const;
     void colorDiff(const FileData &fileData);
+    QList<TextLineData> assemblyRows(const QStringList &lines,
+                                                       const QMap<int, int> &lineSpans,
+                                                       const QMap<int, int> &changedPositions,
+                                                       QMap<int, int> *outputChangedPositions) const;
     ChunkData calculateOriginalData(const QList<Diff> &diffList) const;
     FileData calculateContextData(const ChunkData &originalData) const;
     void showDiff();