LiteralEncoding.scala

LiteralEncoding.scala

object LiteralEncoding {
  private val Hex = "0123456789abcdef".toArray

  private val StringEscapes = {
    val escapes = Map(
      '\b' -> 'b', // backspace
      '\t' -> 't', // tab
      '\n' -> 'n', // linefeed
      '\f' -> 'f', // formfeed
      '\r' -> 'r', // carriage return
      '\\' -> '\\', // backslash
      '"' -> '"'
    )
    (Array.fill('\\'.toInt + 1)('\u0000') /: escapes) { (a, e) => a(e._1) = e._2; a }
  }

  def encode(str: String): String =
    encode(str, new StringBuilder(str.length + 2)).toString
   
  def encode(str: String, sb: StringBuilder): StringBuilder = {
    if(null == str) return sb.append("null");
     
    sb.append('"')
    for(c <- str) {
      if(c <= StringEscapes.length && '\u0000' != StringEscapes(c))
        sb.append('\\').append(StringEscapes(c))
      else if('~' >= c && c >= ' ')
        sb.append(c)
      else {
        sb.append('\\').append('u')
          .append(Hex(c >>> 12 & 0xF))
          .append(Hex(c >>>  8 & 0xF))
          .append(Hex(c >>>  4 & 0xF))
          .append(Hex(c        & 0xF))
      }
    }
    sb.append('"')
  }
}