260 lines
11 KiB
Scheme
260 lines
11 KiB
Scheme
;; -*- mode: scheme; coding: utf-8 -*-
|
|
;;
|
|
;; This module was renamed from (weinholt text base64 (1 0 20100612)) to
|
|
;; (guix base64) by Nikita Karetnikov <nikita@karetnikov.org> on
|
|
;; February 12, 2014.
|
|
;;
|
|
;; Some optimizations made by Ludovic Courtès <ludo@gnu.org>, 2015.
|
|
;; Turned into a Guile module (instead of R6RS).
|
|
;;
|
|
;; This program is free software: you can redistribute it and/or modify
|
|
;; it under the terms of the GNU General Public License as published by
|
|
;; the Free Software Foundation, either version 3 of the License, or
|
|
;; (at your option) any later version.
|
|
;;
|
|
;; This program is distributed in the hope that it will be useful,
|
|
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
;; GNU General Public License for more details.
|
|
;;
|
|
;; You should have received a copy of the GNU General Public License
|
|
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
;;
|
|
;; This file incorporates work covered by the following copyright and
|
|
;; permission notice:
|
|
;;
|
|
;; Copyright © 2009, 2010 Göran Weinholt <goran@weinholt.se>
|
|
;;
|
|
;; 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.
|
|
|
|
;; RFC 4648 Base-N Encodings
|
|
|
|
(define-module (guix base64)
|
|
#:export (base64-encode
|
|
base64-decode
|
|
base64-alphabet
|
|
base64url-alphabet
|
|
get-delimited-base64
|
|
put-delimited-base64)
|
|
#:use-module (srfi srfi-11)
|
|
#:use-module (srfi srfi-60)
|
|
#:use-module (rnrs bytevectors)
|
|
#:use-module (rnrs io ports))
|
|
|
|
|
|
(define-syntax define-alias
|
|
(syntax-rules ()
|
|
((_ new old)
|
|
(define-syntax new (identifier-syntax old)))))
|
|
|
|
;; Force the use of Guile's own primitives to avoid the overhead of its 'fx'
|
|
;; procedures.
|
|
|
|
(define-alias fxbit-field bit-field)
|
|
(define-alias fxarithmetic-shift ash)
|
|
(define-alias fxarithmetic-shift-left ash)
|
|
(define-alias fxand logand)
|
|
(define-alias fxior logior)
|
|
(define-alias fxxor logxor)
|
|
(define-alias fx=? =)
|
|
(define-alias fx+ +)
|
|
(define-alias mod modulo)
|
|
|
|
(define-syntax-rule (assert exp)
|
|
(unless exp
|
|
(throw 'assertion-failure 'exp)))
|
|
|
|
(define base64-alphabet
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
|
|
|
|
(define base64url-alphabet
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_")
|
|
|
|
(define base64-encode
|
|
(case-lambda
|
|
;; Simple interface. Returns a string containing the canonical
|
|
;; base64 representation of the given bytevector.
|
|
((bv)
|
|
(base64-encode bv 0 (bytevector-length bv) #f #f base64-alphabet #f))
|
|
((bv start)
|
|
(base64-encode bv start (bytevector-length bv) #f #f base64-alphabet #f))
|
|
((bv start end)
|
|
(base64-encode bv start end #f #f base64-alphabet #f))
|
|
((bv start end line-length)
|
|
(base64-encode bv start end line-length #f base64-alphabet #f))
|
|
((bv start end line-length no-padding)
|
|
(base64-encode bv start end line-length no-padding base64-alphabet #f))
|
|
((bv start end line-length no-padding alphabet)
|
|
(base64-encode bv start end line-length no-padding alphabet #f))
|
|
;; Base64 encodes the bytes [start,end[ in the given bytevector.
|
|
;; Lines are limited to line-length characters (unless #f),
|
|
;; which must be a multiple of four. To omit the padding
|
|
;; characters (#\=) set no-padding to a true value. If port is
|
|
;; #f, returns a string.
|
|
((bv start end line-length no-padding alphabet port)
|
|
(assert (or (not line-length) (zero? (mod line-length 4))))
|
|
(let-values (((p extract) (if port
|
|
(values port (lambda () (values)))
|
|
(open-string-output-port))))
|
|
(letrec ((put (if line-length
|
|
(let ((chars 0))
|
|
(lambda (p c)
|
|
(when (fx=? chars line-length)
|
|
(set! chars 0)
|
|
(put-char p #\linefeed))
|
|
(set! chars (fx+ chars 1))
|
|
(put-char p c)))
|
|
put-char)))
|
|
(let lp ((i start))
|
|
(cond ((= i end))
|
|
((<= (+ i 3) end)
|
|
(let ((x (bytevector-uint-ref bv i (endianness big) 3)))
|
|
(put p (string-ref alphabet (fxbit-field x 18 24)))
|
|
(put p (string-ref alphabet (fxbit-field x 12 18)))
|
|
(put p (string-ref alphabet (fxbit-field x 6 12)))
|
|
(put p (string-ref alphabet (fxbit-field x 0 6)))
|
|
(lp (+ i 3))))
|
|
((<= (+ i 2) end)
|
|
(let ((x (fxarithmetic-shift-left (bytevector-u16-ref bv i (endianness big)) 8)))
|
|
(put p (string-ref alphabet (fxbit-field x 18 24)))
|
|
(put p (string-ref alphabet (fxbit-field x 12 18)))
|
|
(put p (string-ref alphabet (fxbit-field x 6 12)))
|
|
(unless no-padding
|
|
(put p #\=))))
|
|
(else
|
|
(let ((x (fxarithmetic-shift-left (bytevector-u8-ref bv i) 16)))
|
|
(put p (string-ref alphabet (fxbit-field x 18 24)))
|
|
(put p (string-ref alphabet (fxbit-field x 12 18)))
|
|
(unless no-padding
|
|
(put p #\=)
|
|
(put p #\=)))))))
|
|
(extract)))))
|
|
|
|
;; Decodes a base64 string. The string must contain only pure
|
|
;; unpadded base64 data.
|
|
|
|
(define base64-decode
|
|
(case-lambda
|
|
((str)
|
|
(base64-decode str base64-alphabet #f))
|
|
((str alphabet)
|
|
(base64-decode str alphabet #f))
|
|
((str alphabet port)
|
|
(unless (zero? (mod (string-length str) 4))
|
|
(error 'base64-decode
|
|
"input string must be a multiple of four characters"))
|
|
(let-values (((p extract) (if port
|
|
(values port (lambda () (values)))
|
|
(open-bytevector-output-port))))
|
|
(do ((i 0 (+ i 4)))
|
|
((= i (string-length str))
|
|
(extract))
|
|
(let ((c1 (string-ref str i))
|
|
(c2 (string-ref str (+ i 1)))
|
|
(c3 (string-ref str (+ i 2)))
|
|
(c4 (string-ref str (+ i 3))))
|
|
;; TODO: be more clever than string-index
|
|
(let ((i1 (string-index alphabet c1))
|
|
(i2 (string-index alphabet c2))
|
|
(i3 (string-index alphabet c3))
|
|
(i4 (string-index alphabet c4)))
|
|
(cond ((and i1 i2 i3 i4)
|
|
(let ((x (fxior (fxarithmetic-shift-left i1 18)
|
|
(fxarithmetic-shift-left i2 12)
|
|
(fxarithmetic-shift-left i3 6)
|
|
i4)))
|
|
(put-u8 p (fxbit-field x 16 24))
|
|
(put-u8 p (fxbit-field x 8 16))
|
|
(put-u8 p (fxbit-field x 0 8))))
|
|
((and i1 i2 i3 (char=? c4 #\=)
|
|
(= i (- (string-length str) 4)))
|
|
(let ((x (fxior (fxarithmetic-shift-left i1 18)
|
|
(fxarithmetic-shift-left i2 12)
|
|
(fxarithmetic-shift-left i3 6))))
|
|
(put-u8 p (fxbit-field x 16 24))
|
|
(put-u8 p (fxbit-field x 8 16))))
|
|
((and i1 i2 (char=? c3 #\=) (char=? c4 #\=)
|
|
(= i (- (string-length str) 4)))
|
|
(let ((x (fxior (fxarithmetic-shift-left i1 18)
|
|
(fxarithmetic-shift-left i2 12))))
|
|
(put-u8 p (fxbit-field x 16 24))))
|
|
(else
|
|
(error 'base64-decode "invalid input"
|
|
(list c1 c2 c3 c4)))))))))))
|
|
|
|
(define (get-line-comp f port)
|
|
(if (port-eof? port)
|
|
(eof-object)
|
|
(f (get-line port))))
|
|
|
|
;; Reads the common -----BEGIN/END type----- delimited format from
|
|
;; the given port. Returns two values: a string with the type and a
|
|
;; bytevector containing the base64 decoded data. The second value
|
|
;; is the eof object if there is an eof before the BEGIN delimiter.
|
|
|
|
(define (get-delimited-base64 port)
|
|
(define (get-first-data-line port)
|
|
;; Some MIME data has header fields in the same format as mail
|
|
;; or http. These are ignored.
|
|
(let ((line (get-line-comp string-trim-both port)))
|
|
(cond ((eof-object? line) line)
|
|
((string-index line #\:)
|
|
(let lp () ;read until empty line
|
|
(let ((line (get-line-comp string-trim-both port)))
|
|
(if (string=? line "")
|
|
(get-line-comp string-trim-both port)
|
|
(lp)))))
|
|
(else line))))
|
|
(let ((line (get-line-comp string-trim-both port)))
|
|
(cond ((eof-object? line)
|
|
(values "" (eof-object)))
|
|
((string=? line "")
|
|
(get-delimited-base64 port))
|
|
((and (string-prefix? "-----BEGIN " line)
|
|
(string-suffix? "-----" line))
|
|
(let* ((type (substring line 11 (- (string-length line) 5)))
|
|
(endline (string-append "-----END " type "-----")))
|
|
(let-values (((outp extract) (open-bytevector-output-port)))
|
|
(let lp ((line (get-first-data-line port)))
|
|
(cond ((eof-object? line)
|
|
(error 'get-delimited-base64
|
|
"unexpected end of file"))
|
|
((string-prefix? "-" line)
|
|
(unless (string=? line endline)
|
|
(error 'get-delimited-base64
|
|
"bad end delimiter" type line))
|
|
(values type (extract)))
|
|
(else
|
|
(unless (and (= (string-length line) 5)
|
|
(string-prefix? "=" line)) ;Skip Radix-64 checksum
|
|
(base64-decode line base64-alphabet outp))
|
|
(lp (get-line-comp string-trim-both port))))))))
|
|
(else ;skip garbage (like in openssl x509 -in foo -text output).
|
|
(get-delimited-base64 port)))))
|
|
|
|
(define put-delimited-base64
|
|
(case-lambda
|
|
((port type bv line-length)
|
|
(display (string-append "-----BEGIN " type "-----\n") port)
|
|
(base64-encode bv 0 (bytevector-length bv)
|
|
line-length #f base64-alphabet port)
|
|
(display (string-append "\n-----END " type "-----\n") port))
|
|
((port type bv)
|
|
(put-delimited-base64 port type bv 76))))
|