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Diffstat (limited to 'src/clojure/contrib/base64.clj')
| -rw-r--r-- | src/clojure/contrib/base64.clj | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/clojure/contrib/base64.clj b/src/clojure/contrib/base64.clj new file mode 100644 index 00000000..5e1e3310 --- /dev/null +++ b/src/clojure/contrib/base64.clj @@ -0,0 +1,99 @@ +;;; base64.clj: Experimental Base-64 encoding and (later) decoding + +;; by Stuart Sierra, http://stuartsierra.com/ +;; August 19, 2009 + +;; Copyright (c) Stuart Sierra, 2009. All rights reserved. The use +;; and distribution terms for this software are covered by the Eclipse +;; Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) +;; which can be found in the file epl-v10.html at the root of this +;; distribution. By using this software in any fashion, you are +;; agreeing to be bound by the terms of this license. You must not +;; remove this notice, or any other, from this software. + + +(ns #^{:doc "Base-64 encoding and (maybe later) decoding. + + This is mainly here as an example. It is much slower than the + Apache Commons Codec implementation or sun.misc.BASE64Encoder." + :author "Stuart Sierra"} + clojure.contrib.base64 + (:import (java.io InputStream Writer ByteArrayInputStream + StringWriter))) + +(def *base64-alphabet* + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=") + +(defn encode + "Encodes bytes of input, writing Base 64 text on output. alphabet + is a 65-character String containing the 64 characters to use in the + encoding; the 65th character is the pad character. line-length is + the maximum number of characters per line, nil for no line breaks." + [#^InputStream input #^Writer output #^String alphabet line-length] + (let [buffer (make-array Byte/TYPE 3)] + (loop [line 0] + (let [len (.read input buffer)] + (when (pos? len) + ;; Pre-boxing the bytes as Integers is more efficient for + ;; Clojure's bit operations. + (let [b0 (Integer/valueOf (int (aget buffer 0))) + b1 (Integer/valueOf (int (aget buffer 1))) + b2 (Integer/valueOf (int (aget buffer 2)))] + (cond (= len 3) + (let [s0 (bit-and 0x3F (bit-shift-right b0 2)) + s1 (bit-and 0x3F + (bit-or (bit-shift-left b0 4) + (bit-shift-right b1 4))) + s2 (bit-and 0x3F + (bit-or (bit-shift-left b1 2) + (bit-shift-right b2 6))) + s3 (bit-and 0x3F b2)] + (.append output (.charAt alphabet s0)) + (.append output (.charAt alphabet s1)) + (.append output (.charAt alphabet s2)) + (.append output (.charAt alphabet s3))) + + (= len 2) + (let [s0 (bit-and 0x3F (bit-shift-right b0 2)) + s1 (bit-and 0x3F + (bit-or (bit-shift-left b0 4) + (bit-shift-right b1 4))) + s2 (bit-and 0x3F (bit-shift-left b1 2))] + (.append output (.charAt alphabet s0)) + (.append output (.charAt alphabet s1)) + (.append output (.charAt alphabet s2)) + (.append output (.charAt alphabet 64))) + + (= len 1) + (let [s0 (bit-and 0x3F (bit-shift-right b0 2)) + s1 (bit-and 0x3F (bit-shift-left b0 4))] + (.append output (.charAt alphabet s0)) + (.append output (.charAt alphabet s1)) + (.append output (.charAt alphabet 64)) + (.append output (.charAt alphabet 64))))) + (if (and line-length (> (+ line 4) line-length)) + (do (.append output \newline) + (recur 0)) + (recur (+ line 4)))))))) + +(defn encode-str + "Encodes String in base 64; returns a String. If not specified, + encoding is UTF-8 and line-length is nil." + ([s] (encode-str s "UTF-8" nil)) + ([#^String s #^String encoding line-length] + (let [output (StringWriter.)] + (encode (ByteArrayInputStream. (.getBytes s encoding)) + output *base64-alphabet* line-length) + (.toString output)))) + + +;;; tests + +;; (deftest t-encode-str +;; (is (= (encode-str "") "")) +;; (is (= (encode-str "f") "Zg==")) +;; (is (= (encode-str "fo") "Zm8=")) +;; (is (= (encode-str "foo") "Zm9v")) +;; (is (= (encode-str "foob") "Zm9vYg==")) +;; (is (= (encode-str "fooba") "Zm9vYmE=")) +;; (is (= (encode-str "foobar") "Zm9vYmFy"))) |