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Adding bytevector support to base64 lib.

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This commit is contained in:
Alex Shinn 2014-03-21 17:38:49 +09:00
parent 1e06cd215a
commit f425126a11
3 changed files with 193 additions and 133 deletions
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157
lib/chibi/base64.scm
View file

@ -45,24 +45,24 @@
(vector-set! res (char->integer #\=) *pad-char*)
res))
(define (base64-decode-char c)
(vector-ref *base64-decode-table* (char->integer c)))
(define (base64-decode-u8 u8)
(vector-ref *base64-decode-table* u8))
(define *base64-encode-table*
(let ((res (make-vector 64)))
(let lp ((i 0)) ; map letters
(cond
((<= i 25)
(vector-set! res i (integer->char (+ i 65)))
(vector-set! res (+ i 26) (integer->char (+ i 97)))
(vector-set! res i (+ i 65))
(vector-set! res (+ i 26) (+ i 97))
(lp (+ i 1)))))
(let lp ((i 0)) ; map numbers
(cond
((<= i 9)
(vector-set! res (+ i 52) (integer->char (+ i 48)))
(vector-set! res (+ i 52) (+ i 48))
(lp (+ i 1)))))
(vector-set! res 62 #\+)
(vector-set! res 63 #\/)
(vector-set! res 62 (char->integer #\+))
(vector-set! res 63 (char->integer #\/))
res))
(define (enc i)
@ -90,17 +90,21 @@
;; input, and pass it to the internal base64-decode-string! utility.
;; If the resulting length used is exact, we can return that buffer,
;; otherwise we return the appropriate substring.
(define (base64-decode-string src)
(let* ((len (string-length src))
(define (base64-decode-string str)
(utf8->string (base64-decode-bytevector (string->utf8 str))))
(define (base64-decode-bytevector src)
(let* ((len (bytevector-length src))
(dst-len (* 3 (arithmetic-shift (+ 3 len) -2)))
(dst (make-string dst-len)))
(base64-decode-string!
(dst (make-bytevector dst-len)))
(base64-decode-bytevector!
src 0 len dst
(lambda (src-offset res-len b1 b2 b3)
(let ((res-len (base64-decode-finish dst res-len b1 b2 b3)))
(if (= res-len dst-len)
dst
(substring dst 0 res-len)))))))
(bytevector-copy dst 0 res-len)))))))
;; This is a little funky.
;;
@ -112,7 +116,7 @@
;; really bad about optimizing nested loops of primitives, so we
;; flatten this into a single loop, using conditionals to determine
;; which character is currently being read.
(define (base64-decode-string! src start end dst kont)
(define (base64-decode-bytevector! src start end dst kont)
(let lp ((i start)
(j 0)
(b1 *outside-char*)
@ -120,7 +124,7 @@
(b3 *outside-char*))
(if (>= i end)
(kont i j b1 b2 b3)
(let ((c (base64-decode-char (string-ref src i))))
(let ((c (base64-decode-u8 (bytevector-u8-ref src i))))
(cond
((eqv? c *pad-char*)
(kont i j b1 b2 b3))
@ -133,23 +137,23 @@
((eqv? b3 *outside-char*)
(lp (+ i 1) j b1 b2 c))
(else
(string-set! dst
(bytevector-u8-set!
dst
j
(integer->char
(bitwise-ior (arithmetic-shift b1 2)
(extract-bit-field 2 4 b2))))
(string-set! dst
(extract-bit-field 2 4 b2)))
(bytevector-u8-set!
dst
(+ j 1)
(integer->char
(bitwise-ior
(arithmetic-shift (extract-bit-field 4 0 b2) 4)
(extract-bit-field 4 2 b3))))
(string-set! dst
(extract-bit-field 4 2 b3)))
(bytevector-u8-set!
dst
(+ j 2)
(integer->char
(bitwise-ior
(arithmetic-shift (extract-bit-field 2 0 b3) 6)
c)))
c))
(lp (+ i 1) (+ j 3)
*outside-char* *outside-char* *outside-char*)))))))
@ -162,24 +166,22 @@
((eqv? b1 *outside-char*)
j)
((eqv? b2 *outside-char*)
(string-set! dst j (integer->char (arithmetic-shift b1 2)))
(bytevector-u8-set! dst j (arithmetic-shift b1 2))
(+ j 1))
(else
(string-set! dst
(bytevector-u8-set! dst
j
(integer->char
(bitwise-ior (arithmetic-shift b1 2)
(extract-bit-field 2 4 b2))))
(extract-bit-field 2 4 b2)))
(cond
((eqv? b3 *outside-char*)
(+ j 1))
(else
(string-set! dst
(bytevector-u8-set! dst
(+ j 1)
(integer->char
(bitwise-ior
(arithmetic-shift (extract-bit-field 4 0 b2) 4)
(extract-bit-field 4 2 b3))))
(extract-bit-field 4 2 b3)))
(+ j 2))))))
;;> Variation of the above to read and write to ports.
@ -189,15 +191,20 @@
(out (if (and (pair? o) (pair? (cdr o)))
(cadr o)
(current-output-port))))
(let ((src (make-string decode-src-length))
(dst (make-string decode-dst-length)))
(cond
((not (binary-port? in))
(write-string (base64-decode-string (port->string in)) out))
(else
(let ((src (make-bytevector decode-src-length))
(dst (make-bytevector decode-dst-length)))
(let lp ((offset 0))
(let ((src-len (+ offset
(read-string! decode-src-length src in offset))))
(let ((src-len
(+ offset
(read-bytevector! decode-src-length src in offset))))
(cond
((= src-len decode-src-length)
;; read a full chunk: decode, write and loop
(base64-decode-string!
(base64-decode-bytevector!
src 0 decode-src-length dst
(lambda (src-offset dst-len b1 b2 b3)
(cond
@ -205,32 +212,32 @@
(eqv? #\= (string-ref src src-offset)))
;; done
(let ((dst-len (base64-decode-finish dst dst-len b1 b2 b3)))
(write-string dst out 0 dst-len)))
(write-bytevector dst out 0 dst-len)))
((eqv? b1 *outside-char*)
(write-string dst out 0 dst-len)
(lp 0))
(else
(write-string dst out 0 dst-len)
(write-bytevector dst out 0 dst-len)
;; one to three chars left in buffer
(string-set! src 0 (enc b1))
(bytevector-u8-set! src 0 (enc b1))
(cond
((eqv? b2 *outside-char*)
(lp 1))
(else
(string-set! src 1 (enc b2))
(bytevector-u8-set! src 1 (enc b2))
(cond
((eqv? b3 *outside-char*)
(lp 2))
(else
(string-set! src 2 (enc b3))
(bytevector-u8-set! src 2 (enc b3))
(lp 3))))))))))
(else
;; end of source - just decode and write once
(base64-decode-string!
(base64-decode-bytevector!
src 0 src-len dst
(lambda (src-offset dst-len b1 b2 b3)
(let ((dst-len (base64-decode-finish dst dst-len b1 b2 b3)))
(write-string dst out 0 dst-len)))))))))))
(write-string dst out 0 dst-len)))))))))))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; encoding
@ -239,57 +246,65 @@
;;> official base64 standard as described in RFC3548.
(define (base64-encode-string str)
(let* ((len (string-length str))
(utf8->string (base64-encode-bytevector (string->utf8 str))))
(define (base64-encode-bytevector bv)
(let* ((len (bytevector-length bv))
(quot (quotient len 3))
(rem (- len (* quot 3)))
(res-len (arithmetic-shift (+ quot (if (zero? rem) 0 1)) 2))
(res (make-string res-len)))
(base64-encode-string! str 0 len res)
(res (make-bytevector res-len)))
(base64-encode-bytevector! bv 0 len res)
res))
(define (base64-encode-string! str start end res)
(let* ((res-len (string-length res))
(define (base64-encode-bytevector! bv start end res)
(let* ((res-len (bytevector-length res))
(limit (- end 2)))
(let lp ((i start) (j 0))
(if (>= i limit)
(case (- end i)
((1)
(let ((b1 (char->integer (string-ref str i))))
(string-set! res j (enc (arithmetic-shift b1 -2)))
(string-set! res
(let ((b1 (bytevector-u8-ref bv i)))
(bytevector-u8-set! res j (enc (arithmetic-shift b1 -2)))
(bytevector-u8-set!
res
(+ j 1)
(enc (arithmetic-shift (bitwise-and #b11 b1) 4)))
(string-set! res (+ j 2) #\=)
(string-set! res (+ j 3) #\=)))
(bytevector-u8-set! res (+ j 2) (char->integer #\=))
(bytevector-u8-set! res (+ j 3) (char->integer #\=))))
((2)
(let ((b1 (char->integer (string-ref str i)))
(b2 (char->integer (string-ref str (+ i 1)))))
(string-set! res j (enc (arithmetic-shift b1 -2)))
(string-set! res
(let ((b1 (bytevector-u8-ref bv i))
(b2 (bytevector-u8-ref bv (+ i 1))))
(bytevector-u8-set! res j (enc (arithmetic-shift b1 -2)))
(bytevector-u8-set!
res
(+ j 1)
(enc (bitwise-ior
(arithmetic-shift (bitwise-and #b11 b1) 4)
(extract-bit-field 4 4 b2))))
(string-set! res
(bytevector-u8-set!
res
(+ j 2)
(enc (arithmetic-shift (extract-bit-field 4 0 b2)
2)))
(string-set! res (+ j 3) #\=))))
(let ((b1 (char->integer (string-ref str i)))
(b2 (char->integer (string-ref str (+ i 1))))
(b3 (char->integer (string-ref str (+ i 2)))))
(string-set! res j (enc (arithmetic-shift b1 -2)))
(string-set! res
(bytevector-u8-set! res (+ j 3) (char->integer #\=)))))
(let ((b1 (bytevector-u8-ref bv i))
(b2 (bytevector-u8-ref bv (+ i 1)))
(b3 (bytevector-u8-ref bv (+ i 2))))
(bytevector-u8-set! res j (enc (arithmetic-shift b1 -2)))
(bytevector-u8-set!
res
(+ j 1)
(enc (bitwise-ior
(arithmetic-shift (bitwise-and #b11 b1) 4)
(extract-bit-field 4 4 b2))))
(string-set! res
(bytevector-u8-set!
res
(+ j 2)
(enc (bitwise-ior
(arithmetic-shift (extract-bit-field 4 0 b2) 2)
(extract-bit-field 2 6 b3))))
(string-set! res (+ j 3) (enc (bitwise-and #b111111 b3)))
(bytevector-u8-set! res (+ j 3) (enc (bitwise-and #b111111 b3)))
(lp (+ i 3) (+ j 4)))))))
;;> Variation of the above to read and write to ports.
@ -299,15 +314,19 @@
(out (if (and (pair? o) (pair? (cdr o)))
(cadr o)
(current-output-port))))
(cond
((not (binary-port? in))
(write-string (base64-encode-string (port->string in)) out))
(else
(let ((src (make-string encode-src-length))
(dst (make-string
(arithmetic-shift (quotient encode-src-length 3) 2))))
(let lp ()
(let ((n (read-string! 2048 src in)))
(base64-encode-string! src 0 n dst)
(write-string dst out 0 (* 3 (quotient (+ n 3) 4)))
(let ((n (read-bytevector! src in 0 2048)))
(base64-encode-bytevector! src 0 n dst)
(write-bytevector dst out 0 (* 3 (quotient (+ n 3) 4)))
(if (= n 2048)
(lp)))))))
(lp)))))))))
;;> Return a base64 encoded representation of the string \var{str} as
;;> above, wrapped in =?ENC?B?...?= as per RFC1522, split across

7
lib/chibi/base64.sld
View file

@ -1,7 +1,8 @@
(define-library (chibi base64)
(export base64-encode base64-encode-string
base64-decode base64-decode-string
(export base64-encode base64-encode-string base64-encode-bytevector
base64-decode base64-decode-string base64-decode-bytevector
base64-encode-header)
(import (chibi) (srfi 33) (chibi io))
(import (scheme base) (srfi 33) (chibi io)
(only (chibi) string-concatenate))
(include "base64.scm"))

40
tests/base64-tests.scm Normal file
View file

@ -0,0 +1,40 @@
(import (chibi) (chibi base64) (chibi test))
(test-begin "base64")
(test "YW55IGNhcm5hbCBwbGVhc3VyZS4="
(base64-encode-string "any carnal pleasure."))
(test "YW55IGNhcm5hbCBwbGVhc3VyZQ=="
(base64-encode-string "any carnal pleasure"))
(test "YW55IGNhcm5hbCBwbGVhc3Vy"
(base64-encode-string "any carnal pleasur"))
(test "YW55IGNhcm5hbCBwbGVhc3U="
(base64-encode-string "any carnal pleasu"))
(test "YW55IGNhcm5hbCBwbGVhcw=="
(base64-encode-string "any carnal pleas"))
(test "any carnal pleas"
(base64-decode-string "YW55IGNhcm5hbCBwbGVhcw=="))
(test "any carnal pleasu"
(base64-decode-string "YW55IGNhcm5hbCBwbGVhc3U="))
(test "any carnal pleasur"
(base64-decode-string "YW55IGNhcm5hbCBwbGVhc3Vy"))
(test "any carnal pleas"
(base64-decode-string "YW55IGNhcm5hbCBwbGVhcw"))
(test "any carnal pleasu"
(base64-decode-string "YW55IGNhcm5hbCBwbGVhc3U"))
(test "YW55IGNhcm5hbCBwbGVhc3VyZS4="
(call-with-output-string
(lambda (out)
(call-with-input-string "any carnal pleasure."
(lambda (in) (base64-encode in out))))))
(test "any carnal pleasure."
(call-with-output-string
(lambda (out)
(call-with-input-string "YW55IGNhcm5hbCBwbGVhc3VyZS4="
(lambda (in) (base64-decode in out))))))
(test-end)