Skip to content
Snippets Groups Projects
stream.lisp 62.3 KiB
Newer Older
       (let ((in-type (stream-element-type in))
	     (out-type (stream-element-type out)))
ram's avatar
ram committed
	 (if (equal in-type out-type)
	     in-type `(and ,in-type ,out-type))))
      (:close
       (set-closed-flame stream))
      (t
       (or (if (lisp-stream-p in)
	       (funcall (lisp-stream-misc in) in operation arg1 arg2)
	       (stream-misc-dispatch in operation arg1 arg2))
	   (if (lisp-stream-p out)
	       (funcall (lisp-stream-misc out) out operation arg1 arg2)
	       (stream-misc-dispatch out operation arg1 arg2)))))))
ram's avatar
ram committed

(defun %print-echo-stream (s stream d)
  (declare (ignore d))
  (format stream "#<Echo Stream, Input = ~S, Output = ~S>"
	  (two-way-stream-input-stream s)
	  (two-way-stream-output-stream s)))

(setf (documentation 'make-echo-stream 'function)
  "Returns a bidirectional stream which gets its input from Input-Stream and
   sends its output to Output-Stream.  In addition, all input is echoed to
   the output stream")

;;;; String Input Streams:

(defstruct (string-input-stream
dtc's avatar
dtc committed
	     (:include lisp-stream
		       (in #'string-inch)
		       (bin #'string-binch)
		       (n-bin #'string-stream-read-n-bytes)
		       (misc #'string-in-misc))
	     (:print-function %print-string-input-stream)
					;(:constructor nil)
	     (:constructor internal-make-string-input-stream
			   (string current end)))
ram's avatar
ram committed
  (string nil :type simple-string)
  (current nil :type index)
  (end nil :type index))
ram's avatar
ram committed

(defun %print-string-input-stream (s stream d)
  (declare (ignore s d))
  (write-string "#<String-Input Stream>" stream))
  
(defun string-inch (stream eof-errorp eof-value)
  (let ((string (string-input-stream-string stream))
	(index (string-input-stream-current stream)))
    (declare (simple-string string) (fixnum index))
    (cond ((= index (the index (string-input-stream-end stream)))
ram's avatar
ram committed
	   (eof-or-lose stream eof-errorp eof-value))
	  (t
	   (setf (string-input-stream-current stream) (1+ index))
	   (aref string index)))))

(defun string-binch (stream eof-errorp eof-value)
  (let ((string (string-input-stream-string stream))
	(index (string-input-stream-current stream)))
    (declare (simple-string string)
	     (type index index))
    (cond ((= index (the index (string-input-stream-end stream)))
	   (eof-or-lose stream eof-errorp eof-value))
	  (t
	   (setf (string-input-stream-current stream) (1+ index))
	   (char-code (aref string index))))))

(defun string-stream-read-n-bytes (stream buffer start requested eof-errorp)
  (declare (type string-input-stream stream)
	   (type index start requested))
  (let* ((string (string-input-stream-string stream))
	 (index (string-input-stream-current stream))
	 (available (- (string-input-stream-end stream) index))
	 (copy (min available requested)))
    (declare (simple-string string)
	     (type index index available copy))
    (when (plusp copy)
      (setf (string-input-stream-current stream)
	    (truly-the index (+ index copy)))
      (system:without-gcing
       (system-area-copy (vector-sap string)
			 (* index vm:byte-bits)
			 (if (typep buffer 'system-area-pointer)
			     buffer
			     (vector-sap buffer))
			 (* start vm:byte-bits)
			 (* copy vm:byte-bits))))
    (if (and (> requested copy) eof-errorp)
	(error 'end-of-file :stream stream)
	copy)))
ram's avatar
ram committed
(defun string-in-misc (stream operation &optional arg1 arg2)
  (declare (ignore arg2))
ram's avatar
ram committed
  (case operation
     (if arg1
	 (setf (string-input-stream-current stream) arg1)
	 (string-input-stream-current stream)))
    (:file-length (length (string-input-stream-string stream)))
ram's avatar
ram committed
    (:unread (decf (string-input-stream-current stream)))
    (:listen (or (/= (the fixnum (string-input-stream-current stream))
		     (the fixnum (string-input-stream-end stream)))
		 :eof))
    (:element-type 'base-char)))
ram's avatar
ram committed
  
(defun make-string-input-stream (string &optional
					(start 0) (end (length string)))
  "Returns an input stream which will supply the characters of String between
  Start and End in order."
  (declare (type string string)
	   (type index start)
	   (type (or index null) end))
  (internal-make-string-input-stream (coerce string 'simple-string)
				     start end))
ram's avatar
ram committed

;;;; String Output Streams:

(defstruct (string-output-stream
dtc's avatar
dtc committed
	    (:include lisp-stream
ram's avatar
ram committed
		      (out #'string-ouch)
		      (sout #'string-sout)
		      (misc #'string-out-misc))
	    (:print-function %print-string-output-stream)
	    (:constructor make-string-output-stream ()))
  ;; The string we throw stuff in.
  (string (make-string 40) :type simple-string)
  ;; Index of the next location to use.
  (index 0 :type fixnum))

(defun %print-string-output-stream (s stream d)
  (declare (ignore s d))
  (write-string "#<String-Output Stream>" stream))

(setf (documentation 'make-string-output-stream 'function)
  "Returns an Output stream which will accumulate all output given it for
   the benefit of the function Get-Output-Stream-String.")

(defun string-ouch (stream character)
  (let ((current (string-output-stream-index stream))
	(workspace (string-output-stream-string stream)))
    (declare (simple-string workspace) (fixnum current))
    (if (= current (the fixnum (length workspace)))
	(let ((new-workspace (make-string (* current 2))))
	  (replace new-workspace workspace)
ram's avatar
ram committed
	  (setf (aref new-workspace current) character)
	  (setf (string-output-stream-string stream) new-workspace))
	(setf (aref workspace current) character))
    (setf (string-output-stream-index stream) (1+ current))))

(defun string-sout (stream string start end)
  (declare (simple-string string) (fixnum start end))
  (let* ((current (string-output-stream-index stream))
	 (length (- end start))
	 (dst-end (+ length current))
	 (workspace (string-output-stream-string stream)))
    (declare (simple-string workspace)
	     (fixnum current length dst-end))
    (if (> dst-end (the fixnum (length workspace)))
	(let ((new-workspace (make-string (+ (* current 2) length))))
	  (replace new-workspace workspace :end2 current)
	  (replace new-workspace string
		   :start1 current :end1 dst-end
		   :start2 start :end2 end)
ram's avatar
ram committed
	  (setf (string-output-stream-string stream) new-workspace))
	(replace workspace string
		 :start1 current :end1 dst-end
		 :start2 start :end2 end))
ram's avatar
ram committed
    (setf (string-output-stream-index stream) dst-end)))

(defun string-out-misc (stream operation &optional arg1 arg2)
ram's avatar
ram committed
  (declare (ignore arg2))
ram's avatar
ram committed
  (case operation
ram's avatar
ram committed
	 (string-output-stream-index stream)))
ram's avatar
ram committed
    (:charpos
     (do ((index (1- (the fixnum (string-output-stream-index stream)))
		 (1- index))
	  (count 0 (1+ count))
	  (string (string-output-stream-string stream)))
	 ((< index 0) count)
       (declare (simple-string string)
		(fixnum index count))
       (if (char= (schar string index) #\newline)
	   (return count))))
    (:element-type 'base-char)))
ram's avatar
ram committed

(defun get-output-stream-string (stream)
  "Returns a string of all the characters sent to a stream made by
   Make-String-Output-Stream since the last call to this function."
  (declare (type string-output-stream stream))
  (let* ((length (string-output-stream-index stream))
	 (result (make-string length)))
    (replace result (string-output-stream-string stream))
    (setf (string-output-stream-index stream) 0)
    result))
ram's avatar
ram committed

(defun dump-output-stream-string (in-stream out-stream)
  "Dumps the characters buffer up in the In-Stream to the Out-Stream as
  Get-Output-Stream-String would return them."
dtc's avatar
dtc committed
  (write-string* (string-output-stream-string in-stream) out-stream
		 0 (string-output-stream-index in-stream))
ram's avatar
ram committed
  (setf (string-output-stream-index in-stream) 0))

;;;; Fill-pointer streams:
;;;
;;;    Fill pointer string output streams are not explicitly mentioned in
;;; the CLM, but they are required for the implementation of With-Output-To-String.

(defstruct (fill-pointer-output-stream
dtc's avatar
dtc committed
 	    (:include lisp-stream
ram's avatar
ram committed
		      (out #'fill-pointer-ouch)
		      (sout #'fill-pointer-sout)
		      (misc #'fill-pointer-misc))
	    (:print-function
	     (lambda (s stream d)
	       (declare (ignore s d))
	       (write-string "#<Fill-Pointer String Output Stream>" stream)))
	    (:constructor make-fill-pointer-output-stream (string)))
  ;; The string we throw stuff in.
  string)

 
(defun fill-pointer-ouch (stream character)
  (let* ((buffer (fill-pointer-output-stream-string stream))
	 (current (fill-pointer buffer))
ram's avatar
ram committed
	 (current+1 (1+ current)))
    (declare (fixnum current))
    (with-array-data ((workspace buffer) (start) (end))
      (declare (simple-string workspace))
      (let ((offset-current (+ start current)))
	(declare (fixnum offset-current))
	(if (= offset-current end)
	    (let* ((new-length (* current 2))
		   (new-workspace (make-string new-length)))
	      (declare (simple-string new-workspace))
	      (%primitive byte-blt workspace start new-workspace 0 current)
	      (setf workspace new-workspace)
	      (setf offset-current current)
	      (set-array-header buffer workspace new-length
				current+1 0 new-length nil))
	    (setf (fill-pointer buffer) current+1))
ram's avatar
ram committed
	(setf (schar workspace offset-current) character)))
    current+1))


(defun fill-pointer-sout (stream string start end)
  (declare (simple-string string) (fixnum start end))
  (let* ((buffer (fill-pointer-output-stream-string stream))
	 (current (fill-pointer buffer))
ram's avatar
ram committed
	 (string-len (- end start))
	 (dst-end (+ string-len current)))
    (declare (fixnum current dst-end string-len))
    (with-array-data ((workspace buffer) (dst-start) (dst-length))
      (declare (simple-string workspace))
      (let ((offset-dst-end (+ dst-start dst-end))
	    (offset-current (+ dst-start current)))
	(declare (fixnum offset-dst-end offset-current))
	(if (> offset-dst-end dst-length)
	    (let* ((new-length (+ (the fixnum (* current 2)) string-len))
		   (new-workspace (make-string new-length)))
	      (declare (simple-string new-workspace))
	      (%primitive byte-blt workspace dst-start new-workspace 0 current)
	      (setf workspace new-workspace)
	      (setf offset-current current)
	      (setf offset-dst-end dst-end)
	      (set-array-header buffer workspace new-length
				dst-end 0 new-length nil))
	    (setf (fill-pointer buffer) dst-end))
ram's avatar
ram committed
	(%primitive byte-blt string start
		    workspace offset-current offset-dst-end)))
    dst-end))


(defun fill-pointer-misc (stream operation &optional arg1 arg2)
  (declare (ignore arg1 arg2))
  (case operation
    (:charpos
     (let* ((buffer (fill-pointer-output-stream-string stream))
	    (current (fill-pointer buffer)))
ram's avatar
ram committed
       (with-array-data ((string buffer) (start) (end current))
	 (declare (simple-string string) (ignore start))
	 (let ((found (position #\newline string :test #'char=
				:end end :from-end t)))
	   (if found
	       (- end (the fixnum found))
	       current)))))
     (:element-type 'base-char)))
ram's avatar
ram committed

;;;; Indenting streams:

dtc's avatar
dtc committed
(defstruct (indenting-stream (:include lisp-stream
ram's avatar
ram committed
				       (out #'indenting-out)
				       (sout #'indenting-sout)
				       (misc #'indenting-misc))
			     (:print-function %print-indenting-stream)
			     (:constructor make-indenting-stream (stream)))
  ;; The stream we're based on:
  stream
  ;; How much we indent on each line:
  (indentation 0))

(setf (documentation 'make-indenting-stream 'function)
 "Returns an ouput stream which indents its output by some amount.")

(defun %print-indenting-stream (s stream d)
  (declare (ignore s d))
  (write-string "#<Indenting Stream>" stream))

;;; Indenting-Indent writes the right number of spaces needed to indent output on
;;; the given Stream based on the specified Sub-Stream.

(defmacro indenting-indent (stream sub-stream)
  `(do ((i 0 (+ i 60))
	(indentation (indenting-stream-indentation ,stream)))
       ((>= i indentation))
dtc's avatar
dtc committed
     (write-string*
      "                                                            "
      ,sub-stream 0 (min 60 (- indentation i)))))
ram's avatar
ram committed

;;; Indenting-Out writes a character to an indenting stream.

(defun indenting-out (stream char)
  (let ((sub-stream (indenting-stream-stream stream)))
dtc's avatar
dtc committed
    (write-char char sub-stream)
ram's avatar
ram committed
    (if (char= char #\newline)
	(indenting-indent stream sub-stream))))

;;; Indenting-Sout writes a string to an indenting stream.

(defun indenting-sout (stream string start end)
  (declare (simple-string string) (fixnum start end))
  (do ((i start)
       (sub-stream (indenting-stream-stream stream)))
      ((= i end))
    (let ((newline (position #\newline string :start i :end end)))
      (cond (newline
dtc's avatar
dtc committed
	     (write-string* string sub-stream i (1+ newline))
ram's avatar
ram committed
	     (indenting-indent stream sub-stream)
	     (setq i (+ newline 1)))
	    (t
dtc's avatar
dtc committed
	     (write-string* string sub-stream i end)
ram's avatar
ram committed
	     (setq i end))))))

;;; Indenting-Misc just treats just the :Line-Length message differently.
;;; Indenting-Charpos says the charpos is the charpos of the base stream minus
;;; the stream's indentation.

(defun indenting-misc (stream operation &optional arg1 arg2)
dtc's avatar
dtc committed
  (let ((sub-stream (indenting-stream-stream stream)))
    (if (lisp-stream-p sub-stream)
	(let ((method (lisp-stream-misc sub-stream)))
	  (case operation
	    (:line-length
	     (let ((line-length (funcall method sub-stream operation)))
	       (if line-length
		   (- line-length (indenting-stream-indentation stream)))))
	    (:charpos
	     (let ((charpos (funcall method sub-stream operation)))
	       (if charpos
		   (- charpos (indenting-stream-indentation stream)))))       
	    (t
	     (funcall method sub-stream operation arg1 arg2))))
	;; Fundamental-stream.
	(case operation
	  (:line-length
	   (let ((line-length (stream-line-length sub-stream)))
	     (if line-length
		 (- line-length (indenting-stream-indentation stream)))))
	  (:charpos
	   (let ((charpos (stream-line-column sub-stream)))
	     (if charpos
		 (- charpos (indenting-stream-indentation stream)))))
	  (t
	   (stream-misc-dispatch sub-stream operation arg1 arg2))))))
dtc's avatar
dtc committed

ram's avatar
ram committed

(proclaim '(maybe-inline read-char unread-char read-byte listen))



;;;; Case frobbing streams, used by format ~(...~).

(defstruct (case-frob-stream
dtc's avatar
dtc committed
	    (:include lisp-stream
		      (:misc #'case-frob-misc))
	    (:constructor %make-case-frob-stream (target out sout)))
  (target (required-argument) :type stream))

(defun make-case-frob-stream (target kind)
  "Returns a stream that sends all output to the stream TARGET, but modifies
   the case of letters, depending on KIND, which should be one of:
     :upcase - convert to upper case.
     :downcase - convert to lower case.
     :capitalize - convert the first letter of words to upper case and the
        rest of the word to lower case.
     :capitalize-first - convert the first letter of the first word to upper
        case and everything else to lower case."
  (declare (type stream target)
	   (type (member :upcase :downcase :capitalize :capitalize-first)
		 kind)
	   (values stream))
  (if (case-frob-stream-p target)
      ;; If we are going to be writing to a stream that already does case
      ;; frobbing, why bother frobbing the case just so it can frob it
      ;; again?
      target
      (multiple-value-bind
	  (out sout)
	  (ecase kind
	    (:upcase
	     (values #'case-frob-upcase-out
		     #'case-frob-upcase-sout))
	    (:downcase
	     (values #'case-frob-downcase-out
		     #'case-frob-downcase-sout))
	    (:capitalize
	     (values #'case-frob-capitalize-out
		     #'case-frob-capitalize-sout))
	    (:capitalize-first
	     (values #'case-frob-capitalize-first-out
		     #'case-frob-capitalize-first-sout)))
	(%make-case-frob-stream target out sout))))

(defun case-frob-misc (stream op &optional arg1 arg2)
  (declare (type case-frob-stream stream))
  (case op
    (:close)
    (t
     (let ((target (case-frob-stream-target stream)))
       (if (lisp-stream-p target)
	   (funcall (lisp-stream-misc target) target op arg1 arg2)
	   (stream-misc-dispatch target op arg1 arg2))))))

(defun case-frob-upcase-out (stream char)
  (declare (type case-frob-stream stream)
ram's avatar
ram committed
	   (type base-char char))
  (let ((target (case-frob-stream-target stream))
	(char (char-upcase char)))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-out target) target char)
	(stream-write-char target char))))

(defun case-frob-upcase-sout (stream str start end)
  (declare (type case-frob-stream stream)
	   (type simple-base-string str)
	   (type index start)
	   (type (or index null) end))
  (let* ((target (case-frob-stream-target stream))
	 (len (length str))
	 (end (or end len))
	 (string (if (and (zerop start) (= len end))
		     (string-upcase str)
		     (nstring-upcase (subseq str start end))))
	 (string-len (- end start)))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-sout target) target string 0 string-len)
	(stream-write-string target string 0 string-len))))

(defun case-frob-downcase-out (stream char)
  (declare (type case-frob-stream stream)
ram's avatar
ram committed
	   (type base-char char))
  (let ((target (case-frob-stream-target stream))
	(char (char-downcase char)))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-out target) target char)
	(stream-write-char target char))))

(defun case-frob-downcase-sout (stream str start end)
  (declare (type case-frob-stream stream)
	   (type simple-base-string str)
	   (type index start)
	   (type (or index null) end))
  (let* ((target (case-frob-stream-target stream))
	 (len (length str))
	 (end (or end len))
	 (string (if (and (zerop start) (= len end))
		     (string-downcase str)
		     (nstring-downcase (subseq str start end))))
	 (string-len (- end start)))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-sout target) target string 0 string-len)
	(stream-write-string target string 0 string-len))))

(defun case-frob-capitalize-out (stream char)
  (declare (type case-frob-stream stream)
ram's avatar
ram committed
	   (type base-char char))
  (let ((target (case-frob-stream-target stream)))
    (cond ((alphanumericp char)
	   (let ((char (char-upcase char)))
	     (if (lisp-stream-p target)
		 (funcall (lisp-stream-out target) target char)
		 (stream-write-char target char)))
	   (setf (case-frob-stream-out stream) #'case-frob-capitalize-aux-out)
	   (setf (case-frob-stream-sout stream)
		 #'case-frob-capitalize-aux-sout))
	  (t
	   (if (lisp-stream-p target)
	       (funcall (lisp-stream-out target) target char)
	       (stream-write-char target char))))))

(defun case-frob-capitalize-sout (stream str start end)
  (declare (type case-frob-stream stream)
	   (type simple-base-string str)
	   (type index start)
	   (type (or index null) end))
  (let* ((target (case-frob-stream-target stream))
	 (str (subseq str start end))
	 (len (length str))
	 (inside-word nil))
    (dotimes (i len)
      (let ((char (schar str i)))
	(cond ((not (alphanumericp char))
	       (setf inside-word nil))
	      (inside-word
	       (setf (schar str i) (char-downcase char)))
	      (t
	       (setf inside-word t)
	       (setf (schar str i) (char-upcase char))))))
    (when inside-word
      (setf (case-frob-stream-out stream)
	    #'case-frob-capitalize-aux-out)
      (setf (case-frob-stream-sout stream)
	    #'case-frob-capitalize-aux-sout))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-sout target) target str 0 len)
	(stream-write-string target str 0 len))))

(defun case-frob-capitalize-aux-out (stream char)
  (declare (type case-frob-stream stream)
ram's avatar
ram committed
	   (type base-char char))
  (let ((target (case-frob-stream-target stream)))
    (cond ((alphanumericp char)
	   (let ((char (char-downcase char)))
	     (if (lisp-stream-p target)
		 (funcall (lisp-stream-out target) target char)
		 (stream-write-char target char))))
	   (if (lisp-stream-p target)
	       (funcall (lisp-stream-out target) target char)
	       (stream-write-char target char))
	   (setf (case-frob-stream-out stream)
		 #'case-frob-capitalize-out)
	   (setf (case-frob-stream-sout stream)
		 #'case-frob-capitalize-sout)))))

(defun case-frob-capitalize-aux-sout (stream str start end)
  (declare (type case-frob-stream stream)
	   (type simple-base-string str)
	   (type index start)
	   (type (or index null) end))
  (let* ((target (case-frob-stream-target stream))
	 (str (subseq str start end))
	 (len (length str))
	 (inside-word t))
    (dotimes (i len)
      (let ((char (schar str i)))
	(cond ((not (alphanumericp char))
	       (setf inside-word nil))
	      (inside-word
	       (setf (schar str i) (char-downcase char)))
	      (t
	       (setf inside-word t)
	       (setf (schar str i) (char-upcase char))))))
    (unless inside-word
      (setf (case-frob-stream-out stream)
	    #'case-frob-capitalize-out)
      (setf (case-frob-stream-sout stream)
	    #'case-frob-capitalize-sout))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-sout target) target str 0 len)
	(stream-write-string target str 0 len))))

(defun case-frob-capitalize-first-out (stream char)
  (declare (type case-frob-stream stream)
ram's avatar
ram committed
	   (type base-char char))
  (let ((target (case-frob-stream-target stream)))
    (cond ((alphanumericp char)
	   (let ((char (char-upcase char)))
	     (if (lisp-stream-p target)
		 (funcall (lisp-stream-out target) target char)
		 (stream-write-char target char)))
	   (setf (case-frob-stream-out stream)
		 #'case-frob-downcase-out)
	   (setf (case-frob-stream-sout stream)
		 #'case-frob-downcase-sout))
	  (t
	   (if (lisp-stream-p target)
	       (funcall (lisp-stream-out target) target char)
	       (stream-write-char target char))))))

(defun case-frob-capitalize-first-sout (stream str start end)
  (declare (type case-frob-stream stream)
	   (type simple-base-string str)
	   (type index start)
	   (type (or index null) end))
  (let* ((target (case-frob-stream-target stream))
	 (str (subseq str start end))
	 (len (length str)))
    (dotimes (i len)
      (let ((char (schar str i)))
	(when (alphanumericp char)
	  (setf (schar str i) (char-upcase char))
	  (do ((i (1+ i) (1+ i)))
	      ((= i len))
	    (setf (schar str i) (char-downcase (schar str i))))
	  (setf (case-frob-stream-out stream)
		#'case-frob-downcase-out)
	  (setf (case-frob-stream-sout stream)
		#'case-frob-downcase-sout)
	  (return))))
    (if (lisp-stream-p target)
	(funcall (lisp-stream-sout target) target str 0 len)
	(stream-write-string target str 0 len))))
chiles's avatar
 
chiles committed


;;;; Public interface from "EXTENSIONS" package.

(defstruct (stream-command (:print-function print-stream-command)
			   (:constructor make-stream-command
					 (name &optional args)))
  (name nil :type symbol)
  (args nil :type list))

(defun print-stream-command (obj str n)
  (declare (ignore n))
  (format str "#<Stream-Cmd ~S>" (stream-command-name obj)))


;;; GET-STREAM-COMMAND -- Public.
;;;
;;; We can't simply call the stream's misc method because nil is an
chiles's avatar
 
chiles committed
;;; ambiguous return value: does it mean text arrived, or does it mean the
;;; stream's misc method had no :get-command implementation.  We can't return
;;; nil until there is text input.  We don't need to loop because any stream
;;; implementing :get-command would wait until it had some input.  If the
;;; LISTEN fails, then we have some random stream we must wait on.
;;;
(defun get-stream-command (stream)
  "This takes a stream and waits for text or a command to appear on it.  If
   text appears before a command, this returns nil, and otherwise it returns
   a command."
dtc's avatar
dtc committed
  (let ((cmdp (funcall (lisp-stream-misc stream) stream :get-command)))
chiles's avatar
 
chiles committed
    (cond (cmdp)
	  ((listen stream)
	   nil)
	  (t
	   ;; This waits for input and returns nil when it arrives.
	   (unread-char (read-char stream) stream)))))


;;; READ-SEQUENCE -- Public
;;;
(defun read-sequence (seq stream &key (start 0) (end nil))
  "Destructively modify SEQ by reading elements from STREAM.
  SEQ is bounded by START and END. SEQ is destructively modified by
  copying successive elements into it from STREAM. If the end of file
  for STREAM is reached before copying all elements of the subsequence,
  then the extra elements near the end of sequence are not updated, and
  the index of the next element is returned."
  (declare (type sequence seq)
	   (type stream stream)
	   (type index start)
	   (type sequence-end end)
	   (values index))
  (let ((end (or end (length seq))))
    (declare (type index end))
    (etypecase seq
      (list
       (let ((read-function
	      (if (subtypep (stream-element-type stream) 'character)
		  #'read-char
		  #'read-byte)))
	 (do ((rem (nthcdr start seq) (rest rem))
	      (i start (1+ i)))
	     ((or (endp rem) (>= i end)) i)
	   (declare (type list rem)
		    (type index i))
	   (let ((el (funcall read-function stream nil :eof)))
	     (when (eq el :eof)
	       (return i))
	     (setf (first rem) el)))))
      (vector
       (with-array-data ((data seq) (offset-start start) (offset-end end))
	 (typecase data
	   ((or (simple-array (unsigned-byte 8) (*))
		(simple-array (signed-byte 8) (*))
		simple-string)
	    (let* ((numbytes (- end start))
		   (bytes-read (system:read-n-bytes
				stream data offset-start numbytes nil)))
	      (if (< bytes-read numbytes)
		  (+ start bytes-read)
		  end)))
	   (t
	    (let ((read-function
		   (if (subtypep (stream-element-type stream) 'character)
		       #'read-char
		       #'read-byte)))
	      (do ((i offset-start (1+ i)))
		  ((>= i offset-end) end)
		(declare (type index i))
		(let ((el (funcall read-function stream nil :eof)))
		  (when (eq el :eof)
		    (return (+ start (- i offset-start))))
		  (setf (aref data i) el)))))))))))

;;; WRITE-SEQUENCE -- Public
;;;
(defun write-sequence (seq stream &key (start 0) (end nil))
  "Write the elements of SEQ bounded by START and END to STREAM."
  (declare (type sequence seq)
	   (type stream stream)
	   (type index start)
	   (type sequence-end end)
	   (values sequence))
  (let ((end (or end (length seq))))
    (declare (type index start end))
    (etypecase seq
      (list
       (let ((write-function
	      (if (subtypep (stream-element-type stream) 'character)
		  #'write-char
		  #'write-byte)))
	 (do ((rem (nthcdr start seq) (rest rem))
	      (i start (1+ i)))
	     ((or (endp rem) (>= i end)) seq)
	   (declare (type list rem)
		    (type index i))
	   (funcall write-function (first rem) stream))))
      (string
dtc's avatar
dtc committed
       (write-string* seq stream start end))
      (vector
       (let ((write-function
	      (if (subtypep (stream-element-type stream) 'character)
		  #'write-char
		  #'write-byte)))
	 (do ((i start (1+ i)))
	     ((>= i end) seq)
	   (declare (type index i))
	   (funcall write-function (aref seq i) stream)))))))