(base64-decode-unit): New function; abolish `base64-decode-1'.

(base64-decode-string): New implementation.
(base64-internal-decode-region): New implementation.

diff --git a/mel-b.el b/mel-b.el
index 4c16f5e..9a50910 100644 (file)
--- a/mel-b.el
+++ b/mel-b.el
@@ -103,18 +103,19 @@ external decoder is called.")
                (base64-num-to-char (ash (logand a 3) 4))) "==")
        ))))
 
-(defun base64-decode-1 (pack)
-  (let ((a (base64-char-to-num (car pack)))
-       (b (base64-char-to-num (nth 1 pack)))
-       (c (nth 2 pack))
-       (d (nth 3 pack)))
-    (concat (char-to-string (logior (ash a 2) (ash b -4)))
-           (if (and c (setq c (base64-char-to-num c)))
-               (concat (char-to-string
-                        (logior (ash (logand b 15) 4) (ash c -2)))
-                       (if (and d (setq d (base64-char-to-num d)))
-                           (char-to-string (logior (ash (logand c 3) 6) d))
-                         ))))))
+(defun base64-decode-unit (a b &optional c d)
+  (condition-case err
+      (concat
+       (char-to-string (logior (ash (base64-char-to-num a) 2)
+                              (ash (setq b (base64-char-to-num b)) -4)))
+       (if (and c (setq c (base64-char-to-num c)))
+          (concat (char-to-string
+                   (logior (ash (logand b 15) 4) (ash c -2)))
+                  (if (and d (setq d (base64-char-to-num d)))
+                      (char-to-string (logior (ash (logand c 3) 6) d))
+                    ))))
+    (error (message (nth 1 err))
+          "")))
 
 
 ;;; @@ base64 encoder/decoder for string
@@ -150,9 +151,42 @@ external decoder is called.")
 
 (defun base64-decode-string (string)
   "Decode STRING which is encoded in base64, and return the result."
-  (mapconcat (function base64-decode-1)
-            (pack-sequence string 4)
-            ""))
+  (let ((len (length string))
+       (i 0)
+       dest)
+    (while (< i len)
+      (let ((a (aref string i)))
+       (setq i (1+ i))
+       (unless (eq a ?\n)
+         (let ((b (aref string i)))
+           (setq i (1+ i))
+           (cond
+            ((eq b ?\n)
+             ;; invalid
+             )
+            ((>= i len)
+             (setq dest (concat dest (base64-decode-unit a b) ))
+             )
+            (t
+             (let ((c (aref string i)))
+               (setq i (1+ i))
+               (cond
+                ((eq c ?\n)
+                 (setq dest (concat dest (base64-decode-unit a b)))
+                 )
+                ((>= i len)
+                 (setq dest (concat dest (base64-decode-unit a b c)))
+                 )
+                (t
+                 (let ((d (aref string i)))
+                   (setq i (1+ i))
+                   (setq dest
+                         (concat dest
+                                 (if (eq c ?\n)
+                                     (base64-decode-unit a b c)
+                                   (base64-decode-unit a b c d))))
+                   ))))))))))
+    dest))
 
 
 ;;; @ base64 encoder/decoder for region
@@ -173,31 +207,10 @@ external decoder is called.")
 
 (defun base64-internal-decode-region (beg end)
   (save-excursion
-    (save-restriction
-      (narrow-to-region beg end)
-      (goto-char (point-min))
-      (while (looking-at ".*\n")
-       (condition-case err
-           (replace-match
-            (base64-decode-string
-             (buffer-substring (match-beginning 0) (1- (match-end 0))))
-            t t)
-         (error
-          (prog1
-              (message (nth 1 err))
-            (replace-match "")))))
-      (if (looking-at ".*$")
-         (condition-case err
-             (replace-match
-              (base64-decode-string
-               (buffer-substring (match-beginning 0) (match-end 0)))
-              t t)
-           (error
-            (prog1
-                (message (nth 1 err))
-              (replace-match "")))
-           ))
-      )))
+    (let ((str (buffer-substring beg end)))
+      (delete-region beg end)
+      (goto-char beg)
+      (insert (base64-decode-string str)))))
 
 (defun base64-external-encode-region (beg end)
   (save-excursion