RailsOnLisp/rol-uri/pstr.lisp

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• Hash : c504f823
  Author : Thomas de Grivel
  Date : 2017-06-21T11:39:20
  

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• pstr.lisp

• ;;
  ;;  RoL-uri  -  URL and URI utilities
  ;;
  ;;  Copyright 2012-2015 Thomas de Grivel <thomas@lowh.net>
  ;;
  ;;  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.
  ;;
  
  ;;  pstr
  
  (defstruct pstr
    (str "" :type string :read-only t)
    (pos 0 :type positive-fixnum))
  
  (defmacro with-pstr ((str pos) x &body body)
    (let ((g!pstr (gensym "PSTR-")))
      `(let ((,g!pstr ,x))
         (let ((,str (pstr-str ,g!pstr))
               (,pos (pstr-pos ,g!pstr)))
           ,@body))))
  
  (defun pstr-copy (x)
    (declare (type pstr x))
    (make-pstr :str (pstr-str x) :pos (pstr-pos x)))
  
  (defun pstr-eat-n (x n)
    (declare (type pstr x)
             (type positive-fixnum n))
    (when (< (length (pstr-str x)) (+ (pstr-pos x) n))
      (error "pstr-eat-n past end of string"))
    (incf (pstr-pos x) n)
    x)
  
  (defun pstr-peek (x &optional (n 0))
    (with-pstr (s p) x
      (let ((i (+ p n)))
        (when (< i (length s))
          (char s i)))))
  
  (defun pstr-eat-char (x char)
    (when (char= char (pstr-peek x))
      (pstr-eat-n x 1)
      char))
  
  (defun pstr-eat-string (x string)
    (with-pstr (s p) x
      (let* ((len (length string))
             (e (+ p len)))
        (when (and (<= e (length s))
                   (string= s string :start1 p :end1 e))
          (pstr-eat-n x len)
          string))))
  
  (define-constant +hexdigits+ "0123456789ABCDEFabcdef"
    :test 'string=)
  
  (defun pstr-eat-pct-encoded (x)
    (when (and (char= #\% (pstr-peek x))
               (find (pstr-peek x 1) +hexdigits+)
               (find (pstr-peek x 2) +hexdigits+))
      (with-pstr (s p) x
        (prog1 (parse-integer s :start p :end (+ 2 p) :radix 16)
          (pstr-eat-n x 3)))))
  
  (defun pstr-eat-if (n fn x)
    (when-let ((r (funcall fn (pstr-peek x))))
      (pstr-eat x n)
      r))
  

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