Merge pull request #24 from ScorexFoundation/perf-opts

More performance optimisations

src/main/scala/scorex/util/encode/Base16.scala

@@ -21,6 +21,7 @@ object Base16 extends BytesEncoder {
   }
 
   def encode(input: Array[Byte]): String = {
+    if (input.length == 0) return ""  // avoid allocation of empty array and new String instance
     val buf = new Array[Char](input.length * 2)
     var j = 0
     while (j < input.length) {

src/main/scala/scorex/util/encode/Base58.scala

@@ -35,7 +35,7 @@ object Base58 extends BytesEncoder {
   override def decode(input: String): Try[Array[Byte]] = Try {
     val decoded = decodeToBigInteger(input)
 
-    val bytes: Array[Byte] = if (decoded == BigInt(0)) Array.empty else decoded.toByteArray
+    val bytes: Array[Byte] = if (decoded == BigInt(0)) Array.emptyByteArray else decoded.toByteArray
     // We may have got one more byte than we wanted, if the high bit of the next-to-last byte was not zero.
     // This  is because BigIntegers are represented with twos-compliment notation,
     // thus if the high bit of the last  byte happens to be 1 another 8 zero bits will be added to

src/main/scala/scorex/util/serialization/Reader.scala

@@ -1,7 +1,7 @@
 package scorex.util.serialization
 
 
-trait Reader {
+abstract class Reader {
 
   /**
     * Type of encoded data

src/main/scala/scorex/util/serialization/Serializer.scala

@@ -2,7 +2,7 @@ package scorex.util.serialization
 
 import scala.util.Try
 
-trait Serializer[TFamily, T <: TFamily, R <: Reader, W <: Writer] {
+abstract class Serializer[TFamily, T <: TFamily, R <: Reader, W <: Writer] {
 
   def serialize(obj: T, w: W): Unit
 

src/main/scala/scorex/util/serialization/VLQByteBufferReader.scala

@@ -22,6 +22,7 @@ class VLQByteBufferReader(buf: ByteBuffer) extends VLQReader {
   @inline override def getByte(): Byte = buf.get
 
   @inline override def getBytes(size: Int): Array[Byte] = {
+    require(size <= remaining, s"Not enough bytes in the buffer: $size")
     val res = new Array[Byte](size)
     buf.get(res)
     res

src/main/scala/scorex/util/serialization/VLQReader.scala

@@ -89,8 +89,8 @@ trait VLQReader extends Reader {
   }
 
   @inline override def getBits(size: Int): Array[Boolean] = {
-    if (size == 0) return Array[Boolean]()
-    val bitSet = util.BitSet.valueOf(getBytes((size + 7) / 8))
+    if (size == 0) return Array.emptyBooleanArray
+    val bitSet = util.BitSet.valueOf(getBytes((size + 7) >> 3))
     val boolArray = new Array[Boolean](size)
     var i = 0
     while (i < size) {

src/main/scala/scorex/util/serialization/VLQWriter.scala

@@ -131,7 +131,7 @@ trait VLQWriter extends Writer {
     }
     // pad the byte array to fix the "no bit was set" behaviour
     // see https://stackoverflow.com/questions/11209600/how-do-i-convert-a-bitset-initialized-with-false-in-a-byte-containing-0-in-java
-    val bytes = util.Arrays.copyOf(bitSet.toByteArray, (xs.length + 7) / 8)
+    val bytes = util.Arrays.copyOf(bitSet.toByteArray, (xs.length + 7) >> 3)
     putBytes(bytes)
     this
   }

src/main/scala/scorex/util/serialization/Writer.scala

@@ -1,6 +1,6 @@
 package scorex.util.serialization
 
-trait Writer {
+abstract class Writer {
 
   /**
     * Type of encoded data

src/test/scala/scorex/util/encode/Base16Specification.scala

@@ -2,4 +2,10 @@ package scorex.util.encode
 
 class Base16Specification extends BytesEncoderSpecification {
   override val encoder: BytesEncoder = Base16
+
+  property("test vectors") {
+     val bytes = Array[Byte](1, 2, 3)
+     Base16.encode(bytes) shouldBe "010203"
+     Base16.encode(Array.emptyByteArray) shouldBe ""
+  }
 }

src/test/scala/scorex/util/serialization/VLQReaderWriterSpecification.scala

@@ -260,6 +260,36 @@ trait VLQReaderWriterSpecification extends AnyPropSpec
     checkFail(Int.MaxValue)
   }
 
+  property("getBytes size check") {
+    val bytes = Array[Byte](1, 2, 3)
+
+    { // successful case
+      val r = byteBufReader(bytes)
+      r.getBytes(3) shouldBe bytes
+    }
+
+    { // successful case 2
+      val r = byteBufReader(bytes)
+      r.position = 2
+      r.getBytes(1) shouldBe bytes.slice(2, 3)
+    }
+
+    { // failure case
+      val r = byteBufReader(bytes)
+      an[IllegalArgumentException] should be thrownBy {
+        r.getBytes(4)
+      }
+    }
+
+    { // failure case 2
+      val r = byteBufReader(bytes)
+      r.position = 2
+      an[IllegalArgumentException] should be thrownBy {
+        r.getBytes(2)
+      }
+    }
+  }
+
   property("getUInt range check assertion") {
     def check(in: Long): Unit =
       byteBufReader(byteArrayWriter().putULong(in).toBytes).getUInt() shouldBe in

src/test/scala/scorex/util/serialization/VQLByteBufferReaderWriterSpecification.scala

@@ -4,7 +4,7 @@ import java.nio.ByteBuffer
 
 import scorex.util.ByteArrayBuilder
 
-class VQLByteBufferReaderWriterSpecification extends VLQReaderWriterSpecification {
+class VLQByteBufferReaderWriterSpecification extends VLQReaderWriterSpecification {
 
   override def byteBufReader(bytes: Array[Byte]): VLQReader = {
     val buf = ByteBuffer.wrap(bytes)