cl-stream/utf8-stream

diff --git a/babel-input-stream.lisp b/babel-input-stream.lisp
new file mode 100644
index 0000000..9d76686
--- /dev/null
+++ b/babel-input-stream.lisp
@@ -0,0 +1,65 @@
+;;
+;;  babel-stream  -  charset encoding/decoding layer for cl-stream
+;;
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
+;;
+;;  Permission to use, copy, modify, and distribute this software for any
+;;  purpose with or without fee is hereby granted, provided that the above
+;;  copyright notice and this permission notice appear in all copies.
+;;
+;;  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+;;  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+;;  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+;;  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+;;  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+;;  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+;;  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+;;
+
+(in-package :babel-stream)
+
+(defclass babel-input-stream (babel-stream input-stream)
+  ((bytes :initform (make-array '(8) :element-type '(unsigned-byte 8))
+          :reader stream-bytes
+          :type (array (unsigned-byte 8)))
+   (bytes-length :initform 0
+                 :accessor stream-bytes-length
+                 :type fixnum+)))
+
+(defmethod stream-read ((stream babel-input-stream))
+  (let* ((underlying-stream (stream-underlying-stream stream))
+         (bytes (stream-bytes stream))
+         (encoding (stream-external-format stream))
+         (mapping (babel::lookup-mapping babel::*string-vector-mappings*
+                                         encoding)))
+    (loop
+       (multiple-value-bind (element state) (stream-read
+                                             underlying-stream)
+         (case state
+           ((nil)
+            (setf (aref bytes (stream-bytes-length stream)) element)
+            (incf (stream-bytes-length stream))
+            (handler-case
+                (let ((string (make-string 1)))
+                  (when (= 1 (funcall (the function (babel::decoder mapping))
+                                      bytes 0 (stream-bytes-length stream)
+                                      string 0))
+                    (setf (stream-bytes-length stream) 0)
+                    (return (values (char string 0) nil))))
+              (babel-encodings:end-of-input-in-character ())))
+           ((:eof)
+            (return (values nil :eof)))
+           ((:non-blocking)
+            (return (values nil :non-blocking)))
+           (otherwise
+            (error 'stream-input-error :stream stream)))))))
+
+(defun babel-input-stream (stream &optional (external-format :utf-8))
+  (make-instance 'babel-input-stream
+                 :external-format external-format
+                 :stream stream))
+
+#+test
+(let ((s (make-instance 'babel-input-stream
+                        :stream (fd-stream:fd-input-stream 0))))
+  (read-line s))
diff --git a/babel-io-stream.lisp b/babel-io-stream.lisp
new file mode 100644
index 0000000..f2c9778
--- /dev/null
+++ b/babel-io-stream.lisp
@@ -0,0 +1,27 @@
+;;
+;;  babel-stream  -  charset encoding/decoding layer for cl-stream
+;;
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
+;;
+;;  Permission to use, copy, modify, and distribute this software for any
+;;  purpose with or without fee is hereby granted, provided that the above
+;;  copyright notice and this permission notice appear in all copies.
+;;
+;;  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+;;  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+;;  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+;;  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+;;  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+;;  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+;;  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+;;
+
+(in-package :babel-stream)
+
+(defclass babel-io-stream (babel-input-stream babel-output-stream)
+  ())
+
+(defun babel-io-stream (stream &optional (external-format :utf-8))
+  (make-instance 'babel-io-stream
+                 :external-format external-format
+                 :stream stream))
diff --git a/babel-output-stream.lisp b/babel-output-stream.lisp
new file mode 100644
index 0000000..c2357ab
--- /dev/null
+++ b/babel-output-stream.lisp
@@ -0,0 +1,55 @@
+;;
+;;  babel-stream  -  charset encoding/decoding layer for cl-stream
+;;
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
+;;
+;;  Permission to use, copy, modify, and distribute this software for any
+;;  purpose with or without fee is hereby granted, provided that the above
+;;  copyright notice and this permission notice appear in all copies.
+;;
+;;  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+;;  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+;;  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+;;  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+;;  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+;;  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+;;  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+;;
+
+(in-package :babel-stream)
+
+(defclass babel-output-stream (babel-stream output-stream)
+  ())
+
+(defmethod stream-write ((stream babel-output-stream) (element fixnum))
+  (assert (typep element '(unsigned-byte 8)))
+  (write (stream-underlying-stream stream) element))
+
+(defmethod stream-write ((stream babel-output-stream)
+                         (element character))
+  (let* ((encoding (stream-external-format stream))
+         (mapping (babel::lookup-mapping babel::*string-vector-mappings*
+                                         encoding))
+         (string (make-string 1 :initial-element element))
+         (bytes (make-array '(8) :element-type '(unsigned-byte 8)))
+         (length (funcall (the function (babel::encoder mapping))
+                          string 0 1 bytes 0)))
+    (write-sequence (stream-underlying-stream stream)
+                    bytes :end length)))
+
+(defmethod stream-flush ((stream babel-output-stream))
+  (stream-flush (stream-underlying-stream stream)))
+
+(defmethod stream-flush-output-buffer ((stream babel-output-stream))
+  (stream-flush-output-buffer (stream-underlying-stream stream)))
+
+(defun babel-output-stream (stream &optional (external-format :utf-8))
+  (make-instance 'babel-output-stream
+                 :external-format external-format
+                 :stream stream))
+
+#+test
+(let ((s (make-instance 'babel-output-stream
+                        :stream (fd-stream:fd-output-stream 1))))
+  (write-sequence s "Hello, world ! ÉÀÖÛŸ")
+  (flush s))
diff --git a/babel-stream.asd b/babel-stream.asd
index fc1dbac..3cd70c4 100644
--- a/babel-stream.asd
+++ b/babel-stream.asd
@@ -1,7 +1,7 @@
 ;;
 ;;  babel-stream  -  charset encoding/decoding layer for cl-stream
 ;;
-;;  Copyright 2017 Thomas de Grivel <thoxdg@gmail.com>
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
 ;;
 ;;  Permission to use, copy, modify, and distribute this software for any
 ;;  purpose with or without fee is hereby granted, provided that the above
@@ -32,4 +32,8 @@
 	       "cl-stream")
   :components
   ((:file "package")
+   (:file "babel-input-stream" :depends-on ("babel-stream"))
+   (:file "babel-io-stream" :depends-on ("babel-input-stream"
+                                         "babel-output-stream"))
+   (:file "babel-output-stream" :depends-on ("babel-stream"))
    (:file "babel-stream" :depends-on ("package"))))
diff --git a/babel-stream.lisp b/babel-stream.lisp
index 1630750..5edbc4a 100644
--- a/babel-stream.lisp
+++ b/babel-stream.lisp
@@ -1,7 +1,7 @@
 ;;
 ;;  babel-stream  -  charset encoding/decoding layer for cl-stream
 ;;
-;;  Copyright 2017 Thomas de Grivel <thoxdg@gmail.com>
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
 ;;
 ;;  Permission to use, copy, modify, and distribute this software for any
 ;;  purpose with or without fee is hereby granted, provided that the above
diff --git a/package.lisp b/package.lisp
index 819bfc3..588acb9 100644
--- a/package.lisp
+++ b/package.lisp
@@ -1,7 +1,7 @@
 ;;
 ;;  babel-stream  -  charset encoding/decoding layer for cl-stream
 ;;
-;;  Copyright 2017 Thomas de Grivel <thoxdg@gmail.com>
+;;  Copyright 2017,2018 Thomas de Grivel <thoxdg@gmail.com>
 ;;
 ;;  Permission to use, copy, modify, and distribute this software for any
 ;;  purpose with or without fee is hereby granted, provided that the above