X-Git-Url: http://cgit.sxemacs.org/?a=blobdiff_plain;f=lisp%2Fmm-util.el;h=3d7bc250449ae431b51540d2143df2a8e9419a15;hb=2ab0ada8eb6db6c8926f5d7fde19b74c7c8d630b;hp=272c0545a56e83081cd2cb5df3d853e3cd07b957;hpb=61cb8921c2682ec4a79439d2fa25e860d880323f;p=gnus

diff --git a/lisp/mm-util.el b/lisp/mm-util.el
index 272c0545a..3d7bc2504 100644
--- a/lisp/mm-util.el
+++ b/lisp/mm-util.el
@@ -73,6 +73,24 @@
 	  (replace-regexp-in-string regexp rep string nil literal)))
      (string-as-unibyte . identity)
      (string-make-unibyte . identity)
+     ;; string-as-multibyte often doesn't really do what you think it does.
+     ;; Example:
+     ;;    (aref (string-as-multibyte "\201") 0) -> 129 (aka ?\201)
+     ;;    (aref (string-as-multibyte "\300") 0) -> 192 (aka ?\300)
+     ;;    (aref (string-as-multibyte "\300\201") 0) -> 192 (aka ?\300)
+     ;;    (aref (string-as-multibyte "\300\201") 1) -> 129 (aka ?\201)
+     ;; but
+     ;;    (aref (string-as-multibyte "\201\300") 0) -> 2240
+     ;;    (aref (string-as-multibyte "\201\300") 1) -> <error>
+     ;; Better use string-to-multibyte or encode-coding-string.
+     ;; If you really need string-as-multibyte somewhere it's usually
+     ;; because you're using the internal emacs-mule representation (maybe
+     ;; because you're using string-as-unibyte somewhere), which is
+     ;; generally a problem in itself.
+     ;; Here is an approximate equivalence table to help think about it:
+     ;; (string-as-multibyte s)   ~= (decode-coding-string s 'emacs-mule)
+     ;; (string-to-multibyte s)   ~= (decode-coding-string s 'binary)
+     ;; (string-make-multibyte s) ~= (decode-coding-string s locale-coding-system)
      (string-as-multibyte . identity)
      (string-to-multibyte
       . (lambda (string)
@@ -910,7 +928,7 @@ If INHIBIT is non-nil, inhibit `mm-inhibit-file-name-handlers'."
     (defun mm-detect-coding-region (start end)
       "Like `detect-coding-region' except returning the best one."
       (let ((coding-systems
-	     (detect-coding-region (point) (point-max))))
+	     (detect-coding-region start end)))
 	(or (car-safe coding-systems)
 	    coding-systems)))
   (defun mm-detect-coding-region (start end)
@@ -1111,5 +1129,5 @@ gzip, bzip2, etc. are allowed."
 
 (provide 'mm-util)
 
-;;; arch-tag: 94dc5388-825d-4fd1-bfa5-2100aa351238
+;; arch-tag: 94dc5388-825d-4fd1-bfa5-2100aa351238
 ;;; mm-util.el ends here