Refactored the chapter flattener and remove the inner function

audiobook/src/main/java/de/ph1b/audiobook/features/chapterReader/matroska/MatroskaChapterFlattener.kt

@@ -5,23 +5,26 @@ import android.util.SparseArray
 
 object MatroskaChapterFlattener {
 
- fun toSparseArray(list: List<MatroskaChapter>, preferredLanguages: List<String>): SparseArray<String> {
- val res = SparseArray<String>()
-
- fun addChapter(chapters: List<MatroskaChapter>, depth: Int) {
- chapters.forEachIndexed { i, chapter ->
- val duration = (chapter.startTime / 1000000).toInt() +
- if (i == 0) depth else 0
- // Simple hack with adding depth is needed because chapter
- // and it's first sub-chapter have usually the same starting time.
- val name = "+ ".repeat(depth) + (chapter.getName(preferredLanguages) ?: "Chapter ${i + 1}")
- res.put(duration, name)
- addChapter(chapter.children, depth + 1)
- }
- }
+ private lateinit var target: SparseArray<String>
+ private lateinit var preferredLanguages: List<String>
 
+ @Synchronized
+ fun toSparseArray(list: List<MatroskaChapter>, preferredLanguages: List<String>): SparseArray<String> {
+ target = SparseArray()
+ this.preferredLanguages = preferredLanguages
  addChapter(list, 0)
+ return target
+ }
 
- return res
+ private fun addChapter(chapters: List<MatroskaChapter>, depth: Int) {
+ chapters.forEachIndexed { i, chapter ->
+ val duration = (chapter.startTime / 1000000).toInt() +
+ if (i == 0) depth else 0
+ // Simple hack with adding depth is needed because chapter
+ // and it's first sub-chapter have usually the same starting time.
+ val name = "+ ".repeat(depth) + (chapter.getName(preferredLanguages) ?: "Chapter ${i + 1}")
+ target.put(duration, name)
+ addChapter(chapter.children, depth + 1)
+ }
  }
 }