Added text.base64Encode and text.base64Decode

LICENSE

@@ -20,6 +20,20 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 
+Code in FS2 is derived in part from scodec. The scodec license is as follows:
+
+Copyright (c) 2013-2014, Michael Pilquist and Paul Chiusano
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+3. Neither the name of the scodec team nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
 Code in FS2 is derived in part from Cats. The Cats license is as follows:
 
 Cats Copyright (c) 2015 Erik Osheim.
@@ -70,4 +84,4 @@ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

core/shared/src/main/scala/fs2/text.scala

@@ -1,9 +1,12 @@
 package fs2
 
+import java.nio.CharBuffer
 import java.nio.charset.Charset
 
 import scala.annotation.tailrec
 
+import scodec.bits.{Bases, ByteVector}
+
 /** Provides utilities for working with streams of text (e.g., encoding byte streams to strings). */
 object text {
   private val utf8Charset = Charset.forName("UTF-8")
@@ -201,4 +204,219 @@ object text {
 
     s => go(Vector.empty, false, s).stream
   }
+
+  /**
+    * Converts a stream of base 64 text in to a stream of bytes.
+    *
+    * If the text is not valid base 64, the pipe fails with an exception. Padding
+    * characters at the end of the input stream are optional, but if present, must
+    * be valid per the base 64 specification. Whitespace characters are ignored.
+    *
+    * The default base 64 alphabet is used by this pipe.
+    */
+  def base64Decode[F[_]: RaiseThrowable]: Pipe[F, String, Byte] =
+    base64Decode(Bases.Alphabets.Base64)
+
+  /**
+    * Like [[base64Decode]] but takes a base 64 alphabet. For example,
+    * `base64Decode(Bases.Alphabets.Base64Url)` will decode URL compatible base 64.
+    */
+  def base64Decode[F[_]: RaiseThrowable](alphabet: Bases.Base64Alphabet): Pipe[F, String, Byte] = {
+    // Adapted from scodec-bits, licensed under 3-clause BSD
+    final case class State(buffer: Int, mod: Int, padding: Int)
+    val Pad = alphabet.pad
+    def paddingError =
+      Left(
+        "Malformed padding - final quantum may optionally be padded with one or two padding characters such that the quantum is completed"
+      )
+
+    def decode(state: State, str: String): Either[String, (State, Chunk[Byte])] = {
+      var buffer = state.buffer
+      var mod = state.mod
+      var padding = state.padding
+      var idx, bidx = 0
+      val acc = new Array[Byte]((str.size + 3) / 4 * 3)
+      while (idx < str.length) {
+        str(idx) match {
+          case c if alphabet.ignore(c) => // ignore
+          case c =>
+            val cidx = {
+              if (padding == 0) {
+                if (c == Pad) {
+                  if (mod == 2 || mod == 3) {
+                    padding += 1
+                    0
+                  } else {
+                    return paddingError
+                  }
+                } else {
+                  try alphabet.toIndex(c)
+                  catch {
+                    case _: IllegalArgumentException =>
+                      return Left(s"Invalid base 64 character '$c' at index $idx")
+                  }
+                }
+              } else {
+                if (c == Pad) {
+                  if (padding == 1 && mod == 3) {
+                    padding += 1
+                    0
+                  } else {
+                    return paddingError
+                  }
+                } else {
+                  return Left(
+                    s"Unexpected character '$c' at index $idx after padding character; only '=' and whitespace characters allowed after first padding character"
+                  )
+                }
+              }
+            }
+            mod match {
+              case 0 =>
+                buffer = (cidx & 0x3f)
+                mod += 1
+              case 1 =>
+                buffer = (buffer << 6) | (cidx & 0x3f)
+                mod += 1
+              case 2 =>
+                buffer = (buffer << 6) | (cidx & 0x3f)
+                mod += 1
+              case 3 =>
+                buffer = (buffer << 6) | (cidx & 0x3f)
+                mod = 0
+                val c = buffer & 0x0ff
+                val b = (buffer >> 8) & 0x0ff
+                val a = (buffer >> 16) & 0x0ff
+                acc(bidx) = a.toByte
+                acc(bidx + 1) = b.toByte
+                acc(bidx + 2) = c.toByte
+                bidx += 3
+            }
+        }
+        idx += 1
+      }
+      val out = Chunk.byteVector(ByteVector.view(acc).take((bidx - padding).toLong))
+      val carry = State(buffer, mod, padding)
+      Right((carry, out))
+    }
+
+    def finish(state: State): Either[String, Chunk[Byte]] =
+      if (state.padding != 0 && state.mod != 0) paddingError
+      else
+        state.mod match {
+          case 0 => Right(Chunk.empty)
+          case 1 => Left("Final base 64 quantum had only 1 digit - must have at least 2 digits")
+          case 2 =>
+            Right(Chunk(((state.buffer >> 4) & 0x0ff).toByte))
+          case 3 =>
+            val buffer = state.buffer
+            Right(
+              Chunk(
+                ((buffer >> 10) & 0x0ff).toByte,
+                ((buffer >> 2) & 0x0ff).toByte
+              )
+            )
+        }
+
+    def go(state: State, s: Stream[F, String]): Pull[F, Byte, Unit] =
+      s.pull.uncons1.flatMap {
+        case Some((hd, tl)) =>
+          decode(state, hd) match {
+            case Right((newState, out)) =>
+              Pull.output(out) >> go(newState, tl)
+            case Left(err) => Pull.raiseError(new IllegalArgumentException(err))
+          }
+        case None =>
+          finish(state) match {
+            case Right(out) => Pull.output(out)
+            case Left(err)  => Pull.raiseError(new IllegalArgumentException(err))
+          }
+      }
+
+    in => go(State(0, 0, 0), in).stream
+  }
+
+  /**
+    * Encodes a byte stream in to a stream of base 64 text.
+    * The default base 64 alphabet is used by this pipe.
+    */
+  def base64Encode[F[_]]: Pipe[F, Byte, String] = base64Encode(Bases.Alphabets.Base64)
+
+  /**
+    * Like [[base64Encode]] but takes a base 64 alphabet. For example,
+    * `base64Encode(Bases.Alphabets.Base64Url)` will encode URL compatible base 64.
+    */
+  def base64Encode[F[_]](alphabet: Bases.Base64Alphabet): Pipe[F, Byte, String] = {
+    // Adapted from scodec-bits, licensed under 3-clause BSD
+    def encode(c: ByteVector): (String, ByteVector) = {
+      val bytes = c.toArray
+      val bldr = CharBuffer.allocate(((bytes.length + 2) / 3) * 4)
+      var idx = 0
+      val mod = bytes.length % 3
+      while (idx < bytes.length - mod) {
+        var buffer = ((bytes(idx) & 0x0ff) << 16) | ((bytes(idx + 1) & 0x0ff) << 8) | (bytes(
+          idx + 2
+        ) & 0x0ff)
+        val fourth = buffer & 0x3f
+        buffer = buffer >> 6
+        val third = buffer & 0x3f
+        buffer = buffer >> 6
+        val second = buffer & 0x3f
+        buffer = buffer >> 6
+        val first = buffer
+        bldr
+          .append(alphabet.toChar(first))
+          .append(alphabet.toChar(second))
+          .append(alphabet.toChar(third))
+          .append(alphabet.toChar(fourth))
+        idx = idx + 3
+      }
+      if (mod == 0) {
+        (bldr.flip.toString, ByteVector.empty)
+      } else if (mod == 1) {
+        (bldr.flip.toString, ByteVector(bytes(idx)))
+      } else {
+        (bldr.flip.toString, ByteVector(bytes(idx), bytes(idx + 1)))
+      }
+    }
+
+    def go(carry: ByteVector, s: Stream[F, Byte]): Pull[F, String, Unit] =
+      s.pull.uncons.flatMap {
+        case Some((hd, tl)) =>
+          val (out, newCarry) = encode(carry ++ hd.toByteVector)
+          Pull.output1(out) >> go(newCarry, tl)
+        case None =>
+          carry.size match {
+            case 0 => Pull.done
+            case 1 =>
+              var buffer = (carry(0) & 0x0ff) << 4
+              val second = buffer & 0x3f
+              buffer = buffer >> 6
+              val first = buffer
+              val out = new String(
+                Array(alphabet.toChar(first), alphabet.toChar(second), alphabet.pad, alphabet.pad)
+              )
+              Pull.output1(out)
+            case 2 =>
+              var buffer = ((carry(0) & 0x0ff) << 10) | ((carry(1) & 0x0ff) << 2)
+              val third = buffer & 0x3f
+              buffer = buffer >> 6
+              val second = buffer & 0x3f
+              buffer = buffer >> 6
+              val first = buffer
+              val out = new String(
+                Array(
+                  alphabet.toChar(first),
+                  alphabet.toChar(second),
+                  alphabet.toChar(third),
+                  alphabet.pad
+                )
+              )
+              Pull.output1(out)
+            case _ => sys.error("carry must be size 0, 1, or 2")
+          }
+      }
+
+    in => go(ByteVector.empty, in).stream
+  }
 }

core/shared/src/test/scala/fs2/TextSpec.scala

@@ -1,6 +1,10 @@
 package fs2
 
 import org.scalatest.{Assertion, Succeeded}
+
+import cats.implicits._
+import scodec.bits.ByteVector
+
 import fs2.text._
 
 class TextSpec extends Fs2Spec {
@@ -230,5 +234,28 @@ class TextSpec extends Fs2Spec {
         }
       }
     }
+
+    "base64Encode" in {
+      forAll { (bs: List[Array[Byte]]) =>
+        bs.map(Chunk.bytes).foldMap(Stream.chunk).through(text.base64Encode).compile.string shouldBe
+          bs.map(ByteVector.view(_)).foldLeft(ByteVector.empty)(_ ++ _).toBase64
+      }
+    }
+
+    "base64Encode andThen base64Decode" in {
+      forAll { (bs: List[Array[Byte]], unchunked: Boolean, rechunkSeed: Long) =>
+        bs.map(Chunk.bytes)
+          .foldMap(Stream.chunk)
+          .through(text.base64Encode)
+          .through {
+            if (unchunked) _.unchunk
+            else _.rechunkRandomlyWithSeed(0.1, 2.0)(rechunkSeed)
+          }
+          .through(text.base64Decode[Fallible])
+          .compile
+          .to(ByteVector) shouldBe
+          Right(bs.map(ByteVector.view(_)).foldLeft(ByteVector.empty)(_ ++ _))
+      }
+    }
   }
 }