172 lines
		
	
	
	
		
			8.1 KiB
		
	
	
	
		
			Common Lisp
		
	
	
	
	
	
			
		
		
	
	
			172 lines
		
	
	
	
		
			8.1 KiB
		
	
	
	
		
			Common Lisp
		
	
	
	
	
	
;; Copyright (c) 2002-2006, Edward Marco Baringer
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;; All rights reserved.
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(in-package :alexandria)
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(defmacro with-open-file* ((stream filespec &key direction element-type
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                                   if-exists if-does-not-exist external-format)
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                           &body body)
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  "Just like WITH-OPEN-FILE, but NIL values in the keyword arguments mean to use
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the default value specified for OPEN."
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  (once-only (direction element-type if-exists if-does-not-exist external-format)
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    `(with-open-stream
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         (,stream (apply #'open ,filespec
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                         (append
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                          (when ,direction
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                            (list :direction ,direction))
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                          (when ,element-type
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                            (list :element-type ,element-type))
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                          (when ,if-exists
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                            (list :if-exists ,if-exists))
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                          (when ,if-does-not-exist
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                            (list :if-does-not-exist ,if-does-not-exist))
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                          (when ,external-format
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                            (list :external-format ,external-format)))))
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       ,@body)))
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(defmacro with-input-from-file ((stream-name file-name &rest args
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                                             &key (direction nil direction-p)
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                                             &allow-other-keys)
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                                &body body)
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  "Evaluate BODY with STREAM-NAME to an input stream on the file
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FILE-NAME. ARGS is sent as is to the call to OPEN except EXTERNAL-FORMAT,
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which is only sent to WITH-OPEN-FILE when it's not NIL."
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  (declare (ignore direction))
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  (when direction-p
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    (error "Can't specify :DIRECTION for WITH-INPUT-FROM-FILE."))
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  `(with-open-file* (,stream-name ,file-name :direction :input ,@args)
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     ,@body))
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(defmacro with-output-to-file ((stream-name file-name &rest args
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                                            &key (direction nil direction-p)
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                                            &allow-other-keys)
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			       &body body)
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  "Evaluate BODY with STREAM-NAME to an output stream on the file
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FILE-NAME. ARGS is sent as is to the call to OPEN except EXTERNAL-FORMAT,
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which is only sent to WITH-OPEN-FILE when it's not NIL."
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  (declare (ignore direction))
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  (when direction-p
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    (error "Can't specify :DIRECTION for WITH-OUTPUT-TO-FILE."))
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  `(with-open-file* (,stream-name ,file-name :direction :output ,@args)
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     ,@body))
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(defun read-stream-content-into-string (stream &key (buffer-size 4096))
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  "Return the \"content\" of STREAM as a fresh string."
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  (check-type buffer-size positive-integer)
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  (let ((*print-pretty* nil))
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    (with-output-to-string (datum)
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      (let ((buffer (make-array buffer-size :element-type 'character)))
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        (loop
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          :for bytes-read = (read-sequence buffer stream)
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          :do (write-sequence buffer datum :start 0 :end bytes-read)
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          :while (= bytes-read buffer-size))))))
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(defun read-file-into-string (pathname &key (buffer-size 4096) external-format)
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  "Return the contents of the file denoted by PATHNAME as a fresh string.
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The EXTERNAL-FORMAT parameter will be passed directly to WITH-OPEN-FILE
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unless it's NIL, which means the system default."
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  (with-input-from-file
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      (file-stream pathname :external-format external-format)
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    (read-stream-content-into-string file-stream :buffer-size buffer-size)))
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(defun write-string-into-file (string pathname &key (if-exists :error)
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                                                    if-does-not-exist
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                                                    external-format)
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  "Write STRING to PATHNAME.
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The EXTERNAL-FORMAT parameter will be passed directly to WITH-OPEN-FILE
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unless it's NIL, which means the system default."
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  (with-output-to-file (file-stream pathname :if-exists if-exists
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                                    :if-does-not-exist if-does-not-exist
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                                    :external-format external-format)
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    (write-sequence string file-stream)))
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(defun read-stream-content-into-byte-vector (stream &key ((%length length))
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                                                         (initial-size 4096))
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  "Return \"content\" of STREAM as freshly allocated (unsigned-byte 8) vector."
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  (check-type length (or null non-negative-integer))
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  (check-type initial-size positive-integer)
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  (do ((buffer (make-array (or length initial-size)
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                           :element-type '(unsigned-byte 8)))
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       (offset 0)
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       (offset-wanted 0))
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      ((or (/= offset-wanted offset)
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           (and length (>= offset length)))
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       (if (= offset (length buffer))
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           buffer
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           (subseq buffer 0 offset)))
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    (unless (zerop offset)
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      (let ((new-buffer (make-array (* 2 (length buffer))
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                                    :element-type '(unsigned-byte 8))))
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        (replace new-buffer buffer)
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        (setf buffer new-buffer)))
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    (setf offset-wanted (length buffer)
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          offset (read-sequence buffer stream :start offset))))
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(defun read-file-into-byte-vector (pathname)
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  "Read PATHNAME into a freshly allocated (unsigned-byte 8) vector."
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  (with-input-from-file (stream pathname :element-type '(unsigned-byte 8))
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    (read-stream-content-into-byte-vector stream '%length (file-length stream))))
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(defun write-byte-vector-into-file (bytes pathname &key (if-exists :error)
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                                                       if-does-not-exist)
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  "Write BYTES to PATHNAME."
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  (check-type bytes (vector (unsigned-byte 8)))
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  (with-output-to-file (stream pathname :if-exists if-exists
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                               :if-does-not-exist if-does-not-exist
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                               :element-type '(unsigned-byte 8))
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    (write-sequence bytes stream)))
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(defun copy-file (from to &key (if-to-exists :supersede)
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			       (element-type '(unsigned-byte 8)) finish-output)
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  (with-input-from-file (input from :element-type element-type)
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    (with-output-to-file (output to :element-type element-type
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				    :if-exists if-to-exists)
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      (copy-stream input output
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                   :element-type element-type
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                   :finish-output finish-output))))
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(defun copy-stream (input output &key (element-type (stream-element-type input))
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                    (buffer-size 4096)
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                    (buffer (make-array buffer-size :element-type element-type))
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                    (start 0) end
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                    finish-output)
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  "Reads data from INPUT and writes it to OUTPUT. Both INPUT and OUTPUT must
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be streams, they will be passed to READ-SEQUENCE and WRITE-SEQUENCE and must have
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compatible element-types."
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  (check-type start non-negative-integer)
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  (check-type end (or null non-negative-integer))
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  (check-type buffer-size positive-integer)
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  (when (and end
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             (< end start))
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    (error "END is smaller than START in ~S" 'copy-stream))
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  (let ((output-position 0)
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        (input-position 0))
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    (unless (zerop start)
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      ;; FIXME add platform specific optimization to skip seekable streams
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      (loop while (< input-position start)
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            do (let ((n (read-sequence buffer input
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                                       :end (min (length buffer)
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                                                 (- start input-position)))))
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                 (when (zerop n)
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                   (error "~@<Could not read enough bytes from the input to fulfill ~
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                           the :START ~S requirement in ~S.~:@>" 'copy-stream start))
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                 (incf input-position n))))
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    (assert (= input-position start))
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    (loop while (or (null end) (< input-position end))
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          do (let ((n (read-sequence buffer input
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                                     :end (when end
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                                            (min (length buffer)
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                                                 (- end input-position))))))
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               (when (zerop n)
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                 (if end
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                     (error "~@<Could not read enough bytes from the input to fulfill ~
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                          the :END ~S requirement in ~S.~:@>" 'copy-stream end)
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                     (return)))
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               (incf input-position n)
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               (write-sequence buffer output :end n)
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               (incf output-position n)))
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    (when finish-output
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      (finish-output output))
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    output-position))
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