Move base64 and SHA-1 modules to (web socket) namespace.

1 files changed, 285 insertions, 0 deletions

diff --git a/web/socket/base64.scm b/web/socket/base64.scm
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+++ b/web/socket/base64.scm
@@ -0,0 +1,285 @@
+;; -*- mode: scheme; coding: utf-8 -*-
+;; Copyright © 2009, 2010, 2012, 2013 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.
+#!r6rs
+
+;; RFC 4648 Base-N Encodings
+
+(library (web socket base64)
+  (export base64-encode
+          base64-decode
+          base64-alphabet
+          base64url-alphabet
+          get-delimited-base64
+          put-delimited-base64)
+  (import (rnrs)
+          (only (srfi :13 strings)
+                string-index
+                string-prefix? string-suffix?
+                string-concatenate string-trim-both))
+
+  (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)))))
+
+  ;; Create a lookup table for the alphabet and remember the latest table.
+  (define get-decode-table
+    (let ((ascii-table #f)
+          (extra-table '())     ;in the unlikely case of unicode chars
+          (table-alphabet #f))
+      (lambda (alphabet)
+        (unless (eq? alphabet table-alphabet)
+          ;; Rebuild the table.
+          (do ((ascii (make-vector 128 #f))
+               (extra '())
+               (i 0 (+ i 1)))
+              ((= i (string-length alphabet))
+               (set! ascii-table ascii)
+               (set! extra-table extra))
+            (let ((c (char->integer (string-ref alphabet i))))
+              (if (fx<=? c 127)
+                  (vector-set! ascii c i)
+                  (set! extra (cons (cons c i) extra)))))
+          (set! table-alphabet alphabet))
+        (values ascii-table extra-table))))
+
+  ;; Decodes a correctly padded base64 string, optionally ignoring
+  ;; non-alphabet characters.
+  (define base64-decode
+    (case-lambda
+      ((str)
+       (base64-decode str base64-alphabet #f))
+      ((str alphabet)
+       (base64-decode str alphabet #f))
+      ((str alphabet port)
+       (base64-decode str alphabet port #t))
+      ((str alphabet port strict?)
+       (define (pad? c) (eqv? c (char->integer #\=)))
+       (let-values (((p extract) (if port
+                                     (values port (lambda () (values)))
+                                     (open-bytevector-output-port)))
+                    ((ascii extra) (get-decode-table alphabet)))
+         (define-syntax lookup
+           (syntax-rules ()
+             ((_ c) (or (and (fx<=? c 127) (vector-ref ascii c))
+                        (cond ((assv c extra) => cdr)
+                              (else #f))))))
+         (let* ((len (if strict?
+                         (string-length str)
+                         (let lp ((i (fx- (string-length str) 1)))
+                           ;; Skip trailing invalid chars.
+                           (cond ((fxzero? i) 0)
+                                 ((let ((c (char->integer (string-ref str i))))
+                                    (or (lookup c) (pad? c)))
+                                  (fx+ i 1))
+                                 (else (lp (fx- i 1))))))))
+           (let lp ((i 0))
+             (cond
+               ((fx=? i len)
+                (extract))
+               ((fx<=? i (fx- len 4))
+                (let lp* ((c1 (char->integer (string-ref str i)))
+                          (c2 (char->integer (string-ref str (fx+ i 1))))
+                          (c3 (char->integer (string-ref str (fx+ i 2))))
+                          (c4 (char->integer (string-ref str (fx+ i 3))))
+                          (i i))
+                  (let ((i1 (lookup c1)) (i2 (lookup c2))
+                        (i3 (lookup c3)) (i4 (lookup c4)))
+                    (cond
+                      ((and i1 i2 i3 i4)
+                       ;; All characters present and accounted for.
+                       ;; The most common case.
+                       (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))
+                         (lp (fx+ i 4))))
+                      ((and i1 i2 i3 (pad? c4) (= i (- len 4)))
+                       ;; One padding character at the end of the input.
+                       (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))
+                         (lp (fx+ i 4))))
+                      ((and i1 i2 (pad? c3) (pad? c4) (= i (- len 4)))
+                       ;; Two padding characters.
+                       (let ((x (fxior (fxarithmetic-shift-left i1 18)
+                                       (fxarithmetic-shift-left i2 12))))
+                         (put-u8 p (fxbit-field x 16 24))
+                         (lp (fx+ i 4))))
+                      ((not strict?)
+                       ;; Non-alphabet characters.
+                       (let lp ((i i) (c* '()) (n 4))
+                         (cond ((fxzero? n)
+                                ;; Found four valid characters.
+                                (lp* (cadddr c*) (caddr c*) (cadr c*) (car c*)
+                                     (fx- i 4)))
+                               ((fx=? i len)
+                                (error 'base64-decode
+                                       "Invalid input in non-strict mode."
+                                       i c*))
+                               (else
+                                ;; Gather alphabetic (or valid
+                                ;; padding) characters.
+                                (let ((c (char->integer (string-ref str i))))
+                                  (cond ((or (lookup c)
+                                             (and (pad? c)
+                                                  (fx<=? n 2)
+                                                  (fx=? i (fx- len n))))
+                                         (lp (fx+ i 1) (cons c c*) (fx- n 1)))
+                                        (else
+                                         (lp (fx+ i 1) c* n))))))))
+                      (else
+                       (error 'base64-decode
+                              "Invalid input in strict mode."
+                              c1 c2 c3 c4))))))
+               (else
+                (error 'base64-decode
+                       "The input is too short, it may be missing padding."
+                       i)))))))))
+
+  (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
+    (case-lambda
+      ((port)
+       (get-delimited-base64 port #t))
+      ((port strict)
+       (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)))))