Hex string in Scala

Hex.scala

/*
 * Copyright (c) 2017 Yuki Ono
 * Licensed under the MIT License.
 */

package func_hex

import Integer.toHexString
import Integer.parseInt

object Hex extends App {    
    def proceduralEncode(bytes: Array[Byte]): String = {
        val sb = new StringBuffer(bytes.length * 2)
        
        for (b <- bytes) {            
            sb.append(toHexString((b >>> 4) & 0x0F))
            sb.append(toHexString(b & 0x0F))
        }
        
        sb.toString()
    }
    
    def fpEncode(bytes: Array[Byte]): String = {
        def toRight(b: Byte) = toHexString((b >>> 4) & 0x0F)
        def toLeft(b: Byte) = toHexString(b & 0x0F);
        
        //bytes.map(b => toRight(b) + toLeft(b)).mkString
        bytes.flatMap(b => Array(toRight(b), toLeft(b))).mkString
    }
    
    def proceduralDecode(hex: String): Array[Byte] = {
        require(hex.length % 2 == 0)
        
        val bytes = new Array[Byte](hex.length / 2)
        
        var i = 0
        while (i < bytes.length) {
            bytes(i) = parseInt(hex.substring(i * 2, i * 2 + 2), 16).toByte
            i += 1
        }
        
        bytes
    }
    
    def fpDecode(hex: String): Array[Byte] = {
        require(hex.length % 2 == 0)
        
        def hexToByte(s: String) = parseInt(s, 16).toByte
        hex.grouped(2).map(hexToByte).toArray
    }
    
    val testBytes = Array(1, 2, 3, 4, 5, 11, 12, 13, 14, 15, 251, 252, 253, 254, 255).map(_.toByte)
    
    println(proceduralEncode(testBytes))
    println(fpEncode(testBytes))
    
    val testHex = "01020304050b0c0d0e0ffbfcfdfeff"
    
    println(proceduralDecode(testHex).mkString(","))
    println(fpDecode(testHex).mkString(","))
}