use primitive type for better performance

Author: Artem Golovko

src/main/kotlin/a0/A0FrequencyModel.kt

@@ -4,13 +4,13 @@ import commons.NUMBER_OF_CHARS
 
 internal class A0FrequencyModel {
 
-  private val charToIndex = Array<Int>(NUMBER_OF_CHARS) { 0 }
+  private val charToIndex = IntArray(NUMBER_OF_CHARS) { 0 }
 
-  private val indexToChar = Array<Int>(NUMBER_OF_SYMBOLS + 1) { 0 }
+  private val indexToChar = IntArray(NUMBER_OF_SYMBOLS + 1) { 0 }
 
-  private val frequencies = Array<Int>(NUMBER_OF_SYMBOLS + 1) { 0 }
+  private val frequencies = IntArray(NUMBER_OF_SYMBOLS + 1) { 0 }
 
-  private val cumulative = Array<Int>(NUMBER_OF_SYMBOLS + 1) { 0 }
+  private val cumulative = IntArray(NUMBER_OF_SYMBOLS + 1) { 0 }
 
   init {
     (0 until NUMBER_OF_CHARS).forEach {

src/main/kotlin/bwt/BWTDecoder.kt

@@ -20,9 +20,9 @@ private class BWTDecoderWriter(
 
   private val buffer = ByteArray(BLOCK_SIZE + 1 + 2 * Int.SIZE_BYTES)
 
-  private val BWTReverseVector = Array<Int>(BLOCK_SIZE + 1) { 0 }
+  private val BWTReverseVector = IntArray(BLOCK_SIZE + 1) { 0 }
 
-  private val count = Array<Int>(NUMBER_OF_CHARS + 1) { 0 }
+  private val count = IntArray(NUMBER_OF_CHARS + 1) { 0 }
 
   private var bufferLength = -1
 

src/main/kotlin/mtf/MTFCoder.kt

@@ -18,7 +18,7 @@ private class MTFCoderWriter(
   private val output: OutputStream
 ) : CoderWriter {
 
-  private val indexToByte = Array<Int>(NUMBER_OF_CHARS) { it }
+  private val indexToByte = IntArray(NUMBER_OF_CHARS) { it }
 
   override fun writeEncoded() {
     input.forEachByte { byte ->

src/main/kotlin/mtf/MTFDecoder.kt

@@ -18,7 +18,7 @@ private class MTFDecoderWriter(
   private val output: OutputStream
 ) : DecoderWriter {
 
-  private val indexToByte = Array<Int>(NUMBER_OF_CHARS) { it }
+  private val indexToByte = IntArray(NUMBER_OF_CHARS) { it }
 
   override fun writeDecoded() {
     input.forEachByte { index ->