cl-stream/utf8-stream/babel-stream.lisp

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• Hash : b0b88b82
  Author : Thomas de Grivel
  Date : 2017-06-18T14:36:15
  

  stream-element-type

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• babel-stream.lisp

• ;;
  ;;  babel-stream  -  charset encoding/decoding layer for cl-stream
  ;;
  ;;  Copyright 2017 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-stream (stream)
    ((underlying-stream :initarg :stream
                        :accessor stream-underlying-stream
                        :type stream)
     (external-format :initarg :external-format
                      :initform :utf-8
                      :accessor stream-external-format
                      :type symbol)))
  
  (defmethod initialize-instance :after ((stream babel-stream)
                                         &rest initargs
                                         &key &allow-other-keys)
    (declare (ignore initargs))
    (assert (equal '(unsigned-byte 8)
                   (stream-element-type (stream-underlying-stream stream)))))
  
  (defmethod stream-element-type ((stream babel-stream))
    'character)
  
  (defclass babel-input-stream (babel-stream input-stream)
    ())
  
  (defclass babel-output-stream (babel-stream output-stream)
    ())
  
  (defmethod write ((stream babel-output-stream) (element fixnum))
    (assert (typep element '(unsigned-byte 8)))
    (write (stream-underlying-stream stream) element))
  
  (defmethod write ((stream babel-output-stream) (element character))
    (let ((seq (babel:string-to-octets (make-string 1 :initial-element element)
  				     :encoding (stream-external-format stream)
  				     :use-bom nil)))
      (write-sequence (stream-underlying-stream stream)
  		    seq)))
  
  (defmethod flush ((stream babel-output-stream))
    (flush (stream-underlying-stream stream)))
  
  (let ((s (make-instance 'babel-output-stream
  			:stream (fd-stream:fd-output-stream 1))))
    (write s #\é)
    (flush s))
  

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