Juanma, thank you for the lisp code that reproduces the same problem that I am having.

If a space is inserted at the beginning of the buffer, then the result is correct (as stated in my bug report):

(with-temp-buffer
 (insert " ")
 (insert (make-string 20 ?.))
 (decode-coding-region 2 (point-max) 'us-ascii)
 (buffer-string))
" ...................."

(I use 'us-ascii just to show the coding does not matter).

Now, hopefully emacs developers will  be able to understand and fix the problem.


On Sat, Feb 21, 2009 at 9:47 PM, Juanma Barranquero <lekktu@gmail.com> wrote:
On Fri, Feb 20, 2009 at 22:13, mj <mj54590@gmail.com> wrote:

> (apply 'decode-coding-region (point-min) (point-max)  'us-ascii nil)
>
> The original buffer  content would be something like this:
>
> B7040400-12
> some text here
>
> after decode-coding-region is executed, the buffer content became:
>
> ^@7040450-12
> some text here
>
> Where ^@ is actually binary code \0 (not ascii ^ and @). There is another instance
> that a string was decoded and the result is  ^@ prefixed.

Could it be related to bug#1809?

(with-temp-buffer
 (insert (make-string 20 ?.))
 (decode-coding-region 1 (point-max) 'raw-text)
 (buffer-string))

=> "^@..................."

   Juanma