com.github.mauricio.async.db.util.HexCodec.scala Maven / Gradle / Ivy

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/*
 * Copyright 2013 Maurício Linhares
 *
 * Maurício Linhares licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.github.mauricio.async.db.util

/**
 * The code from this class was copied from the Hex class at commons-codec
 */

object HexCodec {

  private final val Digits = Array[Char]('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F')

  private def toDigit( ch : Char, index : Int ) : Int = {
    val digit = Character.digit( ch, 16 )

    if ( digit == -1 ) {
      throw new IllegalArgumentException("Illegal hexadecimal character " + ch + " at index " + index);
    }

    return digit
  }

  /**
   *
   * Turns a HEX based char sequence into a Byte array
   *
   * @param value
   * @param start
   * @return
   */

  def decode( value : CharSequence, start : Int = 0 ) : Array[Byte] = {

    val length = value.length - start
    val end = value.length()

    if ( (length & 0x01) != 0 ) {
      throw new IllegalArgumentException("Odd number of characters. A hex encoded byte array has to be even.")
    }

    val out = new Array[Byte](length >> 1)

    var i = 0
    var j = start

    while ( j < end ) {
      var f = toDigit(value.charAt(j), j) << 4
      j += 1
      f = f | toDigit(value.charAt(j), j)
      j += 1
      out(i) = (f & 0xff).asInstanceOf[Byte]
      i += 1
    }

    out
  }

  /**
   *
   * Encodes a byte array into a String encoded with Hex values.
   *
   * @param bytes
   * @param prefix
   * @return
   */

  def encode( bytes : Array[Byte], prefix : Array[Char] = Array.empty ) : String = {
    val length = (bytes.length * 2) + prefix.length
    val chars = new Array[Char](length)

    if ( prefix.length != 0 ) {
      var x = 0
      while ( x < prefix.length ) {
        chars(x) = prefix(x)
        x += 1
      }
    }

    val dataLength = bytes.length
    var j = prefix.length
    var i = 0

    while ( i < dataLength ) {
      chars(j) = Digits(( 0xF0 & bytes(i)) >>> 4 )
      j += 1
      chars(j) = Digits( 0x0F & bytes(i) )
      j += 1
      i += 1
    }

    new String(chars)
  }

}