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package io.github.marklister.base64
/**
* Base64 encoder
* @author Mark Lister
* (c) Mark Lister 2014
*
* I, the copyright holder of this work, release this work into the public domain.
* This applies worldwide. In some countries this may not be legally possible;
* if so: I grant anyone the right to use this work for any purpose, without any
* conditions, unless such conditions are required by law.
*
* The repo for this Base64 encoder lives at https://github.com/marklister/base64
* Please send your issues, suggestions and pull requests there.
*
*/
object Base64 {
class B64Scheme(val encodeTable: IndexedSeq[Char]) {
lazy val decodeTable = collection.immutable.TreeMap(encodeTable.zipWithIndex: _*)
}
lazy val base64 = new B64Scheme(('A' to 'Z') ++ ('a' to 'z') ++ ('0' to '9') ++ Seq('+', '/'))
lazy val base64Url = new B64Scheme(base64.encodeTable.dropRight(2) ++ Seq('-', '_'))
implicit class Encoder(b: Array[Byte]) {
private[this] val zero = Array(0, 0).map(_.toByte)
lazy val pad = (3 - b.length % 3) % 3
def toBase64(implicit scheme: B64Scheme = base64): String = {
def sixBits(x: Array[Byte]): Seq[Int] = {
val a = (x(0) & 0xfc) >> 2
val b = ((x(0) & 0x3) << 4) + ((x(1) & 0xf0) >> 4)
val c = ((x(1) & 0xf) << 2) + ((x(2) & 0xc0) >> 6)
val d = (x(2)) & 0x3f
Seq(a, b, c, d)
}
((b ++ zero.take(pad)).grouped(3)
.flatMap(sixBits(_))
.map(x => scheme.encodeTable(x))
.toSeq
.dropRight(pad) :+ "=" * pad)
.mkString
}
}
implicit class Decoder(s: String) {
lazy val cleanS = s.reverse.dropWhile(_ == '=').reverse
lazy val pad = s.length - cleanS.length
def toByteArray(implicit scheme: B64Scheme = base64): Array[Byte] = {
def threeBytes(s: Seq[Char]): Array[Byte] = {
val r = s.map(scheme.decodeTable(_)).foldLeft(0)((a,b)=>(a << 6) +b)
java.nio.ByteBuffer.allocate(8).putLong(r).array().takeRight(3)
}
if (pad > 2 || s.length % 4 != 0) throw new java.lang.IllegalArgumentException("Invalid Base64 String:" + s)
if (!cleanS.forall(scheme.encodeTable.contains(_))) throw new java.lang.IllegalArgumentException("Invalid Base64 String:" + s)
(cleanS + "A" * pad)
.grouped(4)
.map(threeBytes(_))
.flatten
.toArray
.dropRight(pad)
}
}
}
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