OAuthEncoder.scala

package com.twitter.jetty

object OAuthEncoder {
  val ALPHA = Set((0x41 to 0x5A):_*) ++ Set((0x61 to 0x7A):_*)
  val DIGIT = Set((0x30 to 0x39):_*)
  val HYPHEN = Set(0x2D)
  val PERIOD = Set(0x2E)
  val UNDERSCORE = Set(0x5F)
  val TILDE = Set(0x7E)
  val UNENCODED = ALPHA ++ DIGIT ++ HYPHEN ++ PERIOD ++ UNDERSCORE ++ TILDE

  val bytesToPercent = Map((0x00 to 0xFF).map {
    b =>
      (b -> "%%%02X".format(b))
  }:_*)

  def encode(s: String) = {
    val rv = new StringBuffer()
    val codePoints = s.codePointCount(0, s.length)
    for (i <- 0 to (codePoints - 1)) {
      val cp = s.codePointAt(i)
      if (UNENCODED.contains(cp)) {
        rv.append(cp.toChar)
      } else {
        // break the code point (which can be multiple bytes)
        // into byte values for percent encoding
        var remainingBytes = cp
        while (remainingBytes != 0) {
          var currByte = remainingBytes & 0xFF
          remainingBytes = remainingBytes >> 8
          rv.append(bytesToPercent(currByte))
        }
      }
    }
    rv
  }
}