com.thejholmes.russound.util.HexUtils.kt Maven / Gradle / Ivy

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package com.thejholmes.russound.util

/**
 *  Set of chars for a half-byte.
 */
private val CHARS = arrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f')

/**
 *  Returns the string of two characters representing the HEX value of the byte.
 */
fun Byte.toHexString(): String {
  val i = this.toInt()
  val char2 = CHARS[i and 0x0f]
  val char1 = CHARS[i shr 4 and 0x0f]
  return "$char1$char2".toUpperCase()
}

fun ByteArray.toHexString(forCommandLine: Boolean = false): String {
  return map(Byte::toHexString)
      .joinToString(
          separator = (if (forCommandLine) "\\x" else ""),
          prefix = if (forCommandLine) "\\x" else "")
}

fun ByteArray.toHexString(): String {
  return map(Byte::toHexString)
      .joinToString(separator = "")
}

private val HEX_CHARS = "0123456789ABCDEF"
fun String.toHexByteArray(): ByteArray {
  val result = ByteArray(length / 2)

  for (i in 0 until length step 2) {
    val firstIndex = HEX_CHARS.indexOf(this[i]);
    val secondIndex = HEX_CHARS.indexOf(this[i + 1]);

    val octet = firstIndex.shl(4).or(secondIndex)
    result[i.shr(1)] = octet.toByte()
  }

  return result
}