  -*- Mode : LISP ; Syntax : COMMON - LISP ; Package : CHUNGA ; Base : 10 -*-
  $ Header : /usr / local / cvsrep / chunga / input.lisp , v 1.18 2008/05/24 03:06:22 edi Exp $

  Copyright ( c ) 2006 - 2010 , Dr.   .   All rights reserved .

;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:

;;;   * Redistributions of source code must retain the above copyright
;;;     notice, this list of conditions and the following disclaimer.

;;;   * 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.

;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
;;; 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 AUTHOR 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.

(in-package :chunga)

(defmethod chunked-input-stream-extensions ((object t))
  "The default method which always returns the empty list."
  nil)

(defmethod chunked-input-stream-trailers ((object t))
  "The default method which always returns the empty list."
  nil)

(defmethod chunked-stream-input-chunking-p ((object t))
  "The default method for all objects which are not of type
CHUNKED-INPUT-STREAM."
  nil)

(defmethod (setf chunked-stream-input-chunking-p) (new-value (stream chunked-input-stream))
  "Switches input chunking for STREAM on or off."
  (unless (eq (not new-value) (not (chunked-stream-input-chunking-p stream)))
    (with-slots (input-limit input-index expecting-crlf-p chunk-extensions chunk-trailers)
        stream
      (cond (new-value
             (setq expecting-crlf-p nil
                   input-limit 0
                   input-index 0
                   chunk-extensions nil
                   chunk-trailers nil))
            (t (when (< input-index input-limit)
                 (error 'parameter-error
                        :stream stream
                        :format-control "Not all chunks from ~S have been read completely."
                        :format-arguments (list stream)))))))
  (setf (slot-value stream 'input-chunking-p) new-value))

(defmethod stream-clear-input ((stream chunked-input-stream))
  "Implements CLEAR-INPUT by resetting the internal chunk buffer."
  (when (chunked-stream-input-chunking-p stream)
    (setf (chunked-stream-input-index stream) 0
          (chunked-stream-input-limit stream) 0))
  ;; clear input on inner stream
  (clear-input (chunked-stream-stream stream))
  nil)

(defmethod chunked-input-available-p ((stream chunked-input-stream))
  "Whether there's unread input waiting in the chunk buffer."
  (< (chunked-stream-input-index stream)
     (chunked-stream-input-limit stream)))

(defmethod stream-listen ((stream chunked-input-stream))
  "We first check if input chunking is enabled and if there's
something in the buffer.  Otherwise we poll the underlying stream."
  (cond ((chunked-stream-input-chunking-p stream)
         (or (chunked-input-available-p stream)
             (fill-buffer stream)))
        (t (listen (chunked-stream-stream stream)))))

(defmethod fill-buffer ((stream chunked-input-stream))
  "Re-fills the chunk buffer.  Returns NIL if chunking has ended."
  (let ((inner-stream (chunked-stream-stream stream))
        ;; set up error function for the functions in `read.lisp'
        (*current-error-function*
         (lambda (last-char expected-chars)
             "The function which is called when an unexpected
character is seen.  Signals INPUT-CHUNKING-BODY-CORRUPTED."
             (error 'input-chunking-body-corrupted
                    :stream stream
                    :last-char last-char
                    :expected-chars expected-chars))))
    (labels ((add-extensions ()
               "Reads chunk extensions \(if there are any) and stores
them into the corresponding slot of the stream."
               (when-let (extensions (read-name-value-pairs inner-stream))
                 (warn 'chunga-warning
                       :stream stream
                       :format-control "Adding uninterpreted extensions to stream ~S."
                       :format-arguments (list stream))
                 (setf (slot-value stream 'chunk-extensions)
                       (append (chunked-input-stream-extensions stream) extensions)))
               (assert-crlf inner-stream))
             (get-chunk-size ()
               "Reads chunk size header \(including optional
extensions) and returns the size."
               (with-character-stream-semantics
                 (when (expecting-crlf-p stream)
                   (assert-crlf inner-stream))
                 (setf (expecting-crlf-p stream) t)
                 ;; read hexadecimal number
                 (let (last-char)
                   (prog1 (loop for weight = (digit-char-p (setq last-char (read-char* inner-stream))
                                                           16)
                                for result = (if weight
                                               (+ weight (* 16 (or result 0)))
                                               (return (or result
                                                           (error 'input-chunking-body-corrupted
                                                                  :stream stream
                                                                  :last-char last-char
                                                                  :expected-chars +hex-digits+)))))
  unread first octet which was n't a digit
                     (unread-char* last-char)
                     (add-extensions))))))
      (let ((chunk-size (get-chunk-size)))
        (with-slots (input-buffer input-limit input-index)
            stream
          (setq input-index 0
                input-limit chunk-size)
          (cond ((zerop chunk-size)
                 ;; turn chunking off
                 (setf (chunked-stream-input-chunking-p stream) nil
                       (slot-value stream 'chunk-trailers) (with-character-stream-semantics
                                                             (read-http-headers inner-stream))
                       input-limit 0)
  return NIL
                 (return-from fill-buffer))
                ((> chunk-size (length input-buffer))
                 ;; replace buffer if it isn't big enough for the next chunk
                 (setq input-buffer (make-array chunk-size :element-type '(unsigned-byte 8)))))
          (unless (= (read-sequence input-buffer inner-stream :start 0 :end chunk-size)
                     chunk-size)
            (error 'input-chunking-unexpected-end-of-file
                   :stream stream))
          chunk-size)))))

(defmethod stream-read-byte ((stream chunked-input-stream))
  "Reads one byte from STREAM.  Checks the chunk buffer first, if
input chunking is enabled.  Re-fills buffer is necessary."
  (unless (chunked-stream-input-chunking-p stream)
    (return-from stream-read-byte (read-byte (chunked-stream-stream stream) nil :eof)))
  (unless (chunked-input-available-p stream)
    (unless (fill-buffer stream)
      (return-from stream-read-byte :eof)))
  (with-slots (input-buffer input-index)
      stream
    (prog1 (aref input-buffer input-index)
      (incf input-index))))

(defmethod stream-read-sequence ((stream chunked-input-stream) sequence start end &key)
  "Fills SEQUENCE by adding data from the chunk buffer and re-filling
it until enough data was read.  Works directly on the underlying
stream if input chunking is off."
  (unless (chunked-stream-input-chunking-p stream)
    (return-from stream-read-sequence
      (read-sequence sequence (chunked-stream-stream stream) :start start :end end)))
  (loop
   (when (>= start end)
     (return-from stream-read-sequence start))   
   (unless (chunked-input-available-p stream)
     (unless (fill-buffer stream)
       (return-from stream-read-sequence start)))
   (with-slots (input-buffer input-limit input-index)
       stream
     (replace sequence input-buffer
              :start1 start :end1 end
              :start2 input-index :end2 input-limit)
     (let ((length (min (- input-limit input-index)
                        (- end start))))
       (incf start length)
       (incf input-index length)))))

 Syntax : COMMON - LISP ; Package : CHUNGA ; Base : 10 -*-
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
   * 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.
 THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
 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 AUTHOR BE LIABLE FOR ANY
 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 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.
 clear input on inner stream
 set up error function for the functions in `read.lisp'
 read hexadecimal number
 turn chunking off
 replace buffer if it isn't big enough for the next chunk
  $ Header : /usr / local / cvsrep / chunga / input.lisp , v 1.18 2008/05/24 03:06:22 edi Exp $

  Copyright ( c ) 2006 - 2010 , Dr.   .   All rights reserved .




  DIRECT , INDIRECT , INCIDENTAL , SPECIAL , EXEMPLARY , OR CONSEQUENTIAL
  INTERRUPTION ) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY ,

(in-package :chunga)

(defmethod chunked-input-stream-extensions ((object t))
  "The default method which always returns the empty list."
  nil)

(defmethod chunked-input-stream-trailers ((object t))
  "The default method which always returns the empty list."
  nil)

(defmethod chunked-stream-input-chunking-p ((object t))
  "The default method for all objects which are not of type
CHUNKED-INPUT-STREAM."
  nil)

(defmethod (setf chunked-stream-input-chunking-p) (new-value (stream chunked-input-stream))
  "Switches input chunking for STREAM on or off."
  (unless (eq (not new-value) (not (chunked-stream-input-chunking-p stream)))
    (with-slots (input-limit input-index expecting-crlf-p chunk-extensions chunk-trailers)
        stream
      (cond (new-value
             (setq expecting-crlf-p nil
                   input-limit 0
                   input-index 0
                   chunk-extensions nil
                   chunk-trailers nil))
            (t (when (< input-index input-limit)
                 (error 'parameter-error
                        :stream stream
                        :format-control "Not all chunks from ~S have been read completely."
                        :format-arguments (list stream)))))))
  (setf (slot-value stream 'input-chunking-p) new-value))

(defmethod stream-clear-input ((stream chunked-input-stream))
  "Implements CLEAR-INPUT by resetting the internal chunk buffer."
  (when (chunked-stream-input-chunking-p stream)
    (setf (chunked-stream-input-index stream) 0
          (chunked-stream-input-limit stream) 0))
  (clear-input (chunked-stream-stream stream))
  nil)

(defmethod chunked-input-available-p ((stream chunked-input-stream))
  "Whether there's unread input waiting in the chunk buffer."
  (< (chunked-stream-input-index stream)
     (chunked-stream-input-limit stream)))

(defmethod stream-listen ((stream chunked-input-stream))
  "We first check if input chunking is enabled and if there's
something in the buffer.  Otherwise we poll the underlying stream."
  (cond ((chunked-stream-input-chunking-p stream)
         (or (chunked-input-available-p stream)
             (fill-buffer stream)))
        (t (listen (chunked-stream-stream stream)))))

(defmethod fill-buffer ((stream chunked-input-stream))
  "Re-fills the chunk buffer.  Returns NIL if chunking has ended."
  (let ((inner-stream (chunked-stream-stream stream))
        (*current-error-function*
         (lambda (last-char expected-chars)
             "The function which is called when an unexpected
character is seen.  Signals INPUT-CHUNKING-BODY-CORRUPTED."
             (error 'input-chunking-body-corrupted
                    :stream stream
                    :last-char last-char
                    :expected-chars expected-chars))))
    (labels ((add-extensions ()
               "Reads chunk extensions \(if there are any) and stores
them into the corresponding slot of the stream."
               (when-let (extensions (read-name-value-pairs inner-stream))
                 (warn 'chunga-warning
                       :stream stream
                       :format-control "Adding uninterpreted extensions to stream ~S."
                       :format-arguments (list stream))
                 (setf (slot-value stream 'chunk-extensions)
                       (append (chunked-input-stream-extensions stream) extensions)))
               (assert-crlf inner-stream))
             (get-chunk-size ()
               "Reads chunk size header \(including optional
extensions) and returns the size."
               (with-character-stream-semantics
                 (when (expecting-crlf-p stream)
                   (assert-crlf inner-stream))
                 (setf (expecting-crlf-p stream) t)
                 (let (last-char)
                   (prog1 (loop for weight = (digit-char-p (setq last-char (read-char* inner-stream))
                                                           16)
                                for result = (if weight
                                               (+ weight (* 16 (or result 0)))
                                               (return (or result
                                                           (error 'input-chunking-body-corrupted
                                                                  :stream stream
                                                                  :last-char last-char
                                                                  :expected-chars +hex-digits+)))))
  unread first octet which was n't a digit
                     (unread-char* last-char)
                     (add-extensions))))))
      (let ((chunk-size (get-chunk-size)))
        (with-slots (input-buffer input-limit input-index)
            stream
          (setq input-index 0
                input-limit chunk-size)
          (cond ((zerop chunk-size)
                 (setf (chunked-stream-input-chunking-p stream) nil
                       (slot-value stream 'chunk-trailers) (with-character-stream-semantics
                                                             (read-http-headers inner-stream))
                       input-limit 0)
  return NIL
                 (return-from fill-buffer))
                ((> chunk-size (length input-buffer))
                 (setq input-buffer (make-array chunk-size :element-type '(unsigned-byte 8)))))
          (unless (= (read-sequence input-buffer inner-stream :start 0 :end chunk-size)
                     chunk-size)
            (error 'input-chunking-unexpected-end-of-file
                   :stream stream))
          chunk-size)))))

(defmethod stream-read-byte ((stream chunked-input-stream))
  "Reads one byte from STREAM.  Checks the chunk buffer first, if
input chunking is enabled.  Re-fills buffer is necessary."
  (unless (chunked-stream-input-chunking-p stream)
    (return-from stream-read-byte (read-byte (chunked-stream-stream stream) nil :eof)))
  (unless (chunked-input-available-p stream)
    (unless (fill-buffer stream)
      (return-from stream-read-byte :eof)))
  (with-slots (input-buffer input-index)
      stream
    (prog1 (aref input-buffer input-index)
      (incf input-index))))

(defmethod stream-read-sequence ((stream chunked-input-stream) sequence start end &key)
  "Fills SEQUENCE by adding data from the chunk buffer and re-filling
it until enough data was read.  Works directly on the underlying
stream if input chunking is off."
  (unless (chunked-stream-input-chunking-p stream)
    (return-from stream-read-sequence
      (read-sequence sequence (chunked-stream-stream stream) :start start :end end)))
  (loop
   (when (>= start end)
     (return-from stream-read-sequence start))   
   (unless (chunked-input-available-p stream)
     (unless (fill-buffer stream)
       (return-from stream-read-sequence start)))
   (with-slots (input-buffer input-limit input-index)
       stream
     (replace sequence input-buffer
              :start1 start :end1 end
              :start2 input-index :end2 input-limit)
     (let ((length (min (- input-limit input-index)
                        (- end start))))
       (incf start length)
       (incf input-index length)))))
