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*remove UNESCAPE-URI, HEX-DIGIT? 

*move HEXCHAR->INT to url.scm
This commit is contained in:
vibr 2004-10-14 17:14:44 +00:00
parent 932f03a638
commit 9e71b351d4
1 changed files with 0 additions and 58 deletions
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58
scheme/lib/uri.scm
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@ -15,64 +15,6 @@
;;; General Web page of URI pointers. ;;; General Web page of URI pointers.
;;; Caution:
;;; Don't use this proc until *after* you've parsed the URL -- unescaping
;;; might introduce reserved chars (like slashes and colons) that could
;;; blow your parse.
(define (unescape-uri s . maybe-start/end)
(let-optionals maybe-start/end ((start 0)
(end (string-length s)))
(let* ((esc-seq? (lambda (i) (and (< (+ i 2) end)
(char=? (string-ref s i) #\%)
(hex-digit? (string-ref s (+ i 1)))
(hex-digit? (string-ref s (+ i 2))))))
(hits (let lp ((i start) (hits 0)) ; count # of esc seqs.
(if (< i end)
(if (esc-seq? i)
(lp (+ i 3) (+ hits 1))
(lp (+ i 1) hits))
hits))))
(if (and (zero? hits) (zero? start) (= end (string-length s)))
s
(let* ((nlen (- (- end start) (* hits 2))) ; the new length
; of the
; unescaped
; string stores
; the result
(ns (make-string nlen)))
(let lp ((i start) (j 0)) ; sweep over the string
(if (< j nlen)
(lp (cond
((esc-seq? i) ; unescape
; escape-sequence
(string-set! ns j
(let ((d1 (string-ref s (+ i 1)))
(d2 (string-ref s (+ i 2))))
(ascii->char (+ (* 16 (hexchar->int d1))
(hexchar->int d2)))))
(+ i 3))
(else (string-set! ns j (string-ref s i))
(+ i 1)))
(+ j 1))))
ns)))))
(define hex-digit?
(let ((hex-digits (string->char-set "0123456789abcdefABCDEF")))
(lambda (c) (char-set-contains? hex-digits c))))
; make use of the fact that numbers and characters are in order in the ascii table
(define (hexchar->int c)
(- (char->ascii c)
(if (char-numeric? c)
(char->ascii #\0)
(- (if (char-upper-case? c)
(char->ascii #\A)
(char->ascii #\a))
10))))
(define int->hexchar (define int->hexchar
(let ((table '#(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9 (let ((table '#(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9
#\A #\B #\C #\D #\E #\F))) #\A #\B #\C #\D #\E #\F)))