DECODE-BASE64-STREAM-TO-SEQUENCE is the only thing that requires anything fancy: We read into an adjustable array. Alternative could be using REDIRECT-STREAM and WITH-OUTPUT-TO-STRING, but that is likely slower (untested). Test cases are kept for now to confirm that qbase64 is conforming to our expectations, but can probably dropped in favor of a few more sample messages in the test suite. :START and :END are sadly no longer supported and need to be replaced by SUBSEQ. Change-Id: I5928aed7551b0dea32ee09518ea6f604b40c2863 Reviewed-on: https://cl.tvl.fyi/c/depot/+/8586 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI Autosubmit: sterni <sternenseemann@systemli.org>
		
			
				
	
	
		
			274 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Common Lisp
		
	
	
	
	
	
			
		
		
	
	
			274 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Common Lisp
		
	
	
	
	
	
;;; streams.lisp --- En/De-coding Streams
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;;; Copyright (C) 2012 by Walter C. Pelissero
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;;; Copyright (C) 2021-2023 by the TVL Authors
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;;; Author: Walter C. Pelissero <walter@pelissero.de>
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;;; Project: mime4cl
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;;; This library is free software; you can redistribute it and/or
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;;; modify it under the terms of the GNU Lesser General Public License
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;;; as published by the Free Software Foundation; either version 2.1
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;;; of the License, or (at your option) any later version.
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;;; This library is distributed in the hope that it will be useful,
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;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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;;; Lesser General Public License for more details.
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;;; You should have received a copy of the GNU Lesser General Public
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;;; License along with this library; if not, write to the Free
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;;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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;;; 02111-1307 USA
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(in-package :mime4cl)
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(defun flexi-stream-root-stream (stream)
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  "Return the non FLEXI-STREAM stream a given chain of FLEXI-STREAMs is based on."
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  (if (typep stream 'flexi-stream)
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      (flexi-stream-root-stream (flexi-stream-stream stream))
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      stream))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defclass coder-stream-mixin ()
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  ((real-stream :type stream
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                :initarg :underlying-stream
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                :reader real-stream)
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   (dont-close :initform nil
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               :initarg :dont-close)))
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(defmethod stream-file-position ((stream coder-stream-mixin))
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  (file-position (slot-value stream 'real-stream)))
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(defmethod (setf stream-file-position) (newval (stream coder-stream-mixin))
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  (file-position (slot-value stream 'real-stream) newval))
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(defclass coder-input-stream-mixin (fundamental-binary-input-stream coder-stream-mixin)
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  ())
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(defclass coder-output-stream-mixin (fundamental-binary-output-stream coder-stream-mixin)
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  ())
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;; TODO(sterni): temporary, ugly measure to make flexi-streams happy
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(defmethod stream-element-type ((stream coder-input-stream-mixin))
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  (declare (ignore stream))
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  '(unsigned-byte 8))
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(defclass quoted-printable-decoder-stream (coder-input-stream-mixin quoted-printable-decoder) ())
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(defclass 8bit-decoder-stream (coder-input-stream-mixin 8bit-decoder) ())
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(defclass quoted-printable-encoder-stream (coder-output-stream-mixin quoted-printable-encoder) ())
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(defclass base64-encoder-stream (coder-output-stream-mixin base64-encoder) ())
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(defclass 8bit-encoder-stream (coder-output-stream-mixin 8bit-encoder) ())
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defmethod initialize-instance :after ((stream coder-stream-mixin) &key &allow-other-keys)
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  (unless (slot-boundp stream 'real-stream)
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    (error "REAL-STREAM is unbound.  Must provide a :UNDERLYING-STREAM argument.")))
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(defmethod initialize-instance ((stream coder-output-stream-mixin) &key &allow-other-keys)
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  (call-next-method)
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  (unless (slot-boundp stream 'output-function)
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    (setf (slot-value stream 'output-function)
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          #'(lambda (char)
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              (write-char char (slot-value stream 'real-stream))))))
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(defmethod initialize-instance ((stream coder-input-stream-mixin) &key &allow-other-keys)
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  (call-next-method)
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  (unless (slot-boundp stream 'input-function)
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    (setf (slot-value stream 'input-function)
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          #'(lambda ()
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              (read-char (slot-value stream 'real-stream) nil)))))
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(defmethod stream-read-byte ((stream coder-input-stream-mixin))
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  (or (decoder-read-byte stream)
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      :eof))
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(defmethod stream-write-byte ((stream coder-output-stream-mixin) byte)
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  (encoder-write-byte stream byte))
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(defmethod close ((stream coder-stream-mixin) &key abort)
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  (with-slots (real-stream dont-close) stream
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    (unless dont-close
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      (close real-stream :abort abort))))
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(defmethod close ((stream coder-output-stream-mixin) &key abort)
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  (unless abort
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    (encoder-finish-output stream))
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  (call-next-method))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defclass encoder-input-stream (fundamental-character-input-stream coder-stream-mixin)
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  ((encoder)
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   (buffer-queue :initform (make-queue)))
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  (:documentation
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   "This is the base class for encoders with the direction swapped. It
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reads from REAL-STREAM a stream of bytes, encodes it and returnes it
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in a stream of character."))
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(defclass quoted-printable-encoder-input-stream (encoder-input-stream) ())
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(defclass base64-encoder-input-stream (encoder-input-stream) ())
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(defclass 8bit-encoder-input-stream (fundamental-character-input-stream coder-stream-mixin) ())
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(defmethod initialize-instance ((stream quoted-printable-encoder-input-stream) &key &allow-other-keys)
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  (call-next-method)
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  (with-slots (encoder buffer-queue) stream
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    (setf encoder
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          (make-instance 'quoted-printable-encoder
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                         :output-function #'(lambda (char)
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                                              (queue-append buffer-queue char))))))
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(defmethod initialize-instance ((stream base64-encoder-input-stream) &key &allow-other-keys)
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  (call-next-method)
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  (with-slots (encoder buffer-queue) stream
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    (setf encoder
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          (make-instance 'base64-encoder
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                         :output-function #'(lambda (char)
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                                              (queue-append buffer-queue char))))))
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(defmethod stream-read-char ((stream encoder-input-stream))
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  (with-slots (encoder buffer-queue real-stream) stream
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    (loop
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       while (queue-empty-p buffer-queue)
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       do (let ((byte (read-byte real-stream nil)))
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            (if byte
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                (encoder-write-byte encoder byte)
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                (progn
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                  (encoder-finish-output encoder)
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                  (queue-append buffer-queue :eof)))))
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    (queue-pop buffer-queue)))
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(defmethod stream-read-char ((stream 8bit-encoder-input-stream))
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  (with-slots (real-stream) stream
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    (aif (read-byte real-stream nil)
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         (code-char it)
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         :eof)))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(defun make-custom-flexi-stream (class stream other-args)
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  (apply #'make-instance
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         class
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         :stream stream
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         (mapcar (lambda (x)
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                   ;; make-flexi-stream has a discrepancy between :initarg of
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                   ;; make-instance and its &key which we mirror here.
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                   (if (eq x :external-format) :flexi-stream-external-format x))
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                 other-args)))
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(defclass adapter-flexi-input-stream (flexi-input-stream)
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  ((ignore-close
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    :initform nil
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    :initarg :ignore-close
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    :documentation
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    "If T, calling CLOSE on the stream does nothing.
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If NIL, the underlying stream is closed."))
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  (:documentation "FLEXI-STREAM that does not close the underlying stream on
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CLOSE if :IGNORE-CLOSE is T."))
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(defmethod close ((stream adapter-flexi-input-stream) &key abort)
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  (declare (ignore abort))
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  (with-slots (ignore-close) stream
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    (unless ignore-close
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      (call-next-method))))
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(defun make-input-adapter (source)
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  (etypecase source
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    ;; If it's already a stream, we need to make sure it's not closed by the adapter
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    (stream
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     (assert (input-stream-p source))
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     (if (and (typep source 'adapter-flexi-input-stream)
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              (slot-value source 'ignore-close))
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         source ; already ignores CLOSE
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         (make-adapter-flexi-input-stream source :ignore-close t)))
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    ;; TODO(sterni): is this necessary? (maybe with (not *lazy-mime-decode*)?)
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    (string
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     (make-input-adapter (string-to-octets source)))
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    ((vector (unsigned-byte 8))
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     (make-in-memory-input-stream source))
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    (pathname
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     (make-flexi-stream (open source :element-type '(unsigned-byte 8))))
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    (file-portion
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     (open-decoded-file-portion source))))
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(defun make-adapter-flexi-input-stream (stream &rest args)
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  "Create a ADAPTER-FLEXI-INPUT-STREAM. Accepts the same keyword arguments as
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MAKE-FLEXI-STREAM as well as :IGNORE-CLOSE. If T, the underlying stream is not
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closed."
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  (make-custom-flexi-stream 'adapter-flexi-input-stream stream args))
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(defclass positioned-flexi-input-stream (adapter-flexi-input-stream)
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  ()
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  (:documentation
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   "FLEXI-INPUT-STREAM that automatically advances the underlying :STREAM to
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the location given by :POSITION. This uses FILE-POSITION internally, so it'll
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only works if the underlying stream position is tracked in bytes. Note that
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the underlying stream is still advanced, so having multiple instances of
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POSITIONED-FLEXI-INPUT-STREAM based with the same underlying stream won't work
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reliably.
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Also supports :IGNORE-CLOSE of ADAPTER-FLEXI-INPUT-STREAM."))
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(defmethod initialize-instance ((stream positioned-flexi-input-stream)
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                                &key &allow-other-keys)
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  (call-next-method)
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  ;; The :POSITION initarg is only informational for flexi-streams: It assumes
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  ;; it is were the stream it got is already at and continuously updates it
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  ;; for querying (via FLEXI-STREAM-POSITION) and bound checking.
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  ;; Since we have streams that are not positioned correctly, we need to do this
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  ;; here using FILE-POSITION. Note that assumes the underlying implementation
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  ;; uses bytes for FILE-POSITION which is not guaranteed (probably some streams
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  ;; even in SBCL don't).
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  (file-position (flexi-stream-stream stream) (flexi-stream-position stream)))
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(defun make-positioned-flexi-input-stream (stream &rest args)
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  "Create a POSITIONED-FLEXI-INPUT-STREAM. Accepts the same keyword arguments as
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MAKE-FLEXI-STREAM as well as :IGNORE-CLOSE. Causes the FILE-POSITION of STREAM to
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be modified to match the :POSITION argument."
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  (make-custom-flexi-stream 'positioned-flexi-input-stream stream args))
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; TODO(sterni): test correct behavior with END NIL
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(defstruct file-portion
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  data                                  ; string or a pathname
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  encoding
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  start
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  end)
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(defun open-decoded-file-portion (file-portion)
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  (with-slots (data encoding start end)
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      file-portion
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    (let* ((binary-stream
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             (etypecase data
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               (pathname
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                (open data :element-type '(unsigned-byte 8)))
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               ((vector (unsigned-byte 8))
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                (flexi-streams:make-in-memory-input-stream data))
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               (stream
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                ;; TODO(sterni): assert that bytes/flexi-stream
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                data)))
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           (params (ccase encoding
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                     ((:quoted-printable :base64) '(:external-format :us-ascii))
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                     (:8bit '(:element-type (unsigned-byte 8)))
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                     (:7bit '(:external-format :us-ascii))))
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           (portion-stream (apply #'make-positioned-flexi-input-stream
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                                  binary-stream
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                                  :position start
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                                  :bound end
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                                  ;; if data is a stream we can't have a
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                                  ;; FILE-PORTION without modifying it when
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                                  ;; reading etc. The least we can do, though,
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                                  ;; is forgo destroying it.
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                                  :ignore-close (typep data 'stream)
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                                  params))
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           (needs-decoder-stream (member encoding '(:quoted-printable
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                                                    :base64))))
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      (if needs-decoder-stream
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          (make-instance
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           (ccase encoding
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             (:quoted-printable 'quoted-printable-decoder-stream)
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             (:base64 'qbase64:decode-stream))
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           :underlying-stream portion-stream)
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          portion-stream))))
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