diff options
| -rw-r--r-- | chickadee/base64.scm | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/chickadee/base64.scm b/chickadee/base64.scm index 6575785..b15fec6 100644 --- a/chickadee/base64.scm +++ b/chickadee/base64.scm @@ -57,15 +57,21 @@ alphabet) bv)) -(define* (base64-decode str #:optional (alphabet base64-alphabet)) +(define* (base64-decode str #:key (alphabet base64-alphabet) (padding? #t)) "Decode the base64 encoded string @var{str} using @var{alphabet} and -return a bytevector containing the decoded data." +return a bytevector containing the decoded data. If @var{padding?} is +@code{#t} then trailing padding characters are expected in the input." (define decoder (alphabet->decoder alphabet)) + (define (fail) (error "invalid base64" str)) (define (decode char) + (unless (char? char) (fail)) (let ((x (bytevector-s8-ref decoder (char->integer char)))) - (when (eq? x -1) - (error "invalid base64 character" char)) + (when (eq? x -1) (fail)) x)) + (define pad? + (if padding? + (lambda (x) (eq? x #\=)) + eof-object?)) (call-with-input-string str (lambda (in) (call-with-output-bytevector @@ -77,8 +83,8 @@ return a bytevector containing the decoded data." (c (read-char in)) (d (read-char in))) (cond - ((eq? d #\=) - (if (eq? c #\=) + ((pad? d) + (if (pad? c) ;; 2 bytes of padding. (let ((x (logior (ash (decode a) 6) (decode b)))) (put-u8 out (ash (logand x #xff0) -4))) @@ -89,8 +95,7 @@ return a bytevector containing the decoded data." (put-u8 out (ash (logand x #x3fc00) -10)) (put-u8 out (ash (logand x #x3fc) -2)))) ;; Input should be fully consumed at this point. - (unless (eof-object? (peek-char in)) - (error "invalid base64 string" str))) + (unless (eof-object? (peek-char in)) (fail))) (else (let ((x (logior (ash (decode a) 18) (ash (decode b) 12) @@ -108,9 +113,11 @@ return a bytevector containing the decoded data." alphabet) bv)) -(define* (base64-encode bv #:optional (alphabet base64-alphabet)) +(define* (base64-encode bv #:key (alphabet base64-alphabet) (padding? #t)) "Encode the bytevector @var{bv} as base64 using -@var{alphabet} and return a string containing the encoded data." +@var{alphabet} and return a string containing the encoded data. If +@var{padding?} is @code{#t} then trailing padding characters are +included in the output." (define encoder (alphabet->encoder alphabet)) (define len (bytevector-length bv)) (define groups (quotient len 3)) @@ -133,9 +140,11 @@ return a bytevector containing the decoded data." (put-char port (encode (ash (logand x #xfc00) -10))) (put-char port (encode (ash (logand x #x03f0) -4))) (put-char port (encode (ash (logand x #x000f) 2))) - (put-char port #\=))) + (when padding? + (put-char port #\=)))) ((eq? padding 2) (let ((x (bytevector-u8-ref bv offset))) (put-char port (encode (ash (logand x #xfc) -2))) (put-char port (encode (ash (logand x #x03) 4))) - (put-string port "=="))))))))) + (when padding? + (put-string port "==")))))))))) |