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|
; ACL2 String Library
; Copyright (C) 2009-2016 Centaur Technology
;
; Contact:
; Centaur Technology Formal Verification Group
; 7600-C N. Capital of Texas Highway, Suite 300, Austin, TX 78731, USA.
; http://www.centtech.com/
;
; License: (An MIT/X11-style license)
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
; DEALINGS IN THE SOFTWARE.
;
; Original author: Jared Davis <jared@centtech.com>
(in-package "STR")
(include-book "cat")
(include-book "hex")
(include-book "std/util/defval" :dir :system)
(include-book "centaur/fty/fixequiv" :dir :system)
(include-book "centaur/fty/basetypes" :dir :system)
(local (include-book "std/lists/nthcdr" :dir :system))
(local (include-book "std/typed-lists/character-listp" :dir :system))
(local (std::add-default-post-define-hook :fix))
(defsection url-encoding
:parents (std/strings)
:short "Functions for % encoding strings for use in URLs, as described in <a
href='http://tools.ietf.org/html/rfc3986'>RFC 3986</a>."
:long "<p>Per <a href='https://www.ietf.org/rfc/rfc3986.txt'>RFC 3986</a>,
the only unreserved characters are ALPHA, DIGIT, @('-'), @('.'), @('_'), and
@('~'). We implement some functions to percent-encode other characters in
character lists and strings.</p>")
(xdoc::order-subtopics url-encoding
(url-encode-string
url-encode-chars
url-encode-char))
(local (xdoc::set-default-parents url-encoding))
(define url-encode-char ((x characterp))
:short "URL encode a single character. (slow, logically nice version)."
:returns (encoding character-listp "Encoded version of X, in proper order.")
:long "<p>See @(see fast-url-encode-char) for an faster, array-lookup
alternative.</p>"
(b* ((x (char-fix x))
((when (or (and (char<= #\A x) (char<= x #\Z))
(and (char<= #\a x) (char<= x #\z))
(and (char<= #\0 x) (char<= x #\9))
(member x '(#\- #\_ #\. #\~))))
(list x))
(hex-code (nat-to-hex-chars (char-code x)))
(hex-code (if (eql (len hex-code) 1)
(cons #\0 hex-code)
hex-code)))
(cons #\% hex-code)))
(define make-url-encode-array ((n natp))
:parents (*url-encode-array*)
:guard (<= n 255)
:hooks nil
(if (zp n)
(list (cons n (url-encode-char (code-char n))))
(cons (cons n (url-encode-char (code-char n)))
(make-url-encode-array (- n 1)))))
(std::defval *url-encode-array*
:short "Array binding character codes to the pre-computed URL encodings."
:showval t
(compress1 'url-encode-array
(cons '(:header :dimensions (256)
:maximum-length 257
:name url-encode-array)
(make-url-encode-array 255))))
(define fast-url-encode-char ((x :type character))
:short "URL encode a single character. (fast, array-based version)"
:inline t
:enabled t
:verify-guards nil
:hooks nil
(mbe :logic (url-encode-char x)
:exec (aref1 'url-encode-array *url-encode-array*
(char-code x)))
///
(local (in-theory (disable aref1)))
(local (defun test (n)
(and (equal (aref1 'url-encode-array *url-encode-array* n)
(url-encode-char (code-char n)))
(if (zp n)
t
(test (- n 1))))))
(local (defthm l0
(implies (and (test n)
(natp n)
(natp i)
(<= i n))
(equal (aref1 'url-encode-array *url-encode-array* i)
(url-encode-char (code-char i))))))
(local (defthm l1
(implies (and (natp i)
(<= i 255))
(equal (aref1 'url-encode-array *url-encode-array* i)
(url-encode-char (code-char i))))
:hints(("Goal" :use ((:instance l0 (n 255)))))))
(local (defthm l2
(implies (characterp x)
(equal (aref1 'url-encode-array *url-encode-array*
(char-code x))
(url-encode-char x)))))
(verify-guards fast-url-encode-char$inline))
(define url-encode-chars-aux ((chars character-listp) acc)
:short "URL encode a list of characters onto an accumulator in reverse order."
:returns (encoded character-listp :hyp (character-listp acc))
(if (atom chars)
acc
(url-encode-chars-aux
(cdr chars)
(revappend (fast-url-encode-char (car chars)) acc)))
///
(defthm true-listp-of-url-encode-chars-aux
(equal (true-listp (url-encode-chars-aux x acc))
(true-listp acc))))
(define url-encode-chars ((x character-listp))
:short "Simple way to URL encode a list of characters."
:returns (encoded character-listp)
:inline t
;; BOZO could use nreverse here
(reverse (url-encode-chars-aux x nil))
///
(defthm true-listp-of-url-encode-chars
(true-listp (url-encode-chars x))
:rule-classes :type-prescription))
(define url-encode-string-aux
:short "Efficiently way to URL encode a string, in reverse order, without
exploding it."
((x stringp)
(n natp)
(xl (eql xl (length x)))
acc)
:guard (<= n xl)
:long "<p>This has such a nice logical definition that we just leave it enabled.</p>"
:enabled t
; Removed after v7-2 by Matt K. since logically, the definition is
; non-recursive:
; :measure (nfix (- (nfix xl) (nfix n)))
:verify-guards nil
:hooks nil
(mbe :logic
(url-encode-chars-aux (nthcdr n (explode x)) acc)
:exec
(b* (((when (mbe :logic (zp (- (nfix xl) (nfix n)))
:exec (eql n xl)))
acc)
(char (char x n))
(encoding (fast-url-encode-char char))
(acc (revappend encoding acc)))
(url-encode-string-aux x (+ 1 (lnfix n)) xl acc)))
///
(local (in-theory (enable url-encode-string-aux
url-encode-chars-aux)))
(verify-guards url-encode-string-aux))
(define url-encode-string
:short "Simple way to URL encode a string."
((x stringp :type string))
:returns (encoded stringp :rule-classes :type-prescription)
:split-types t
:inline t
(let ((x (mbe :logic (str-fix x) :exec x)))
(str::rchars-to-string
(url-encode-string-aux x 0 (length x) nil))))
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