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bug#50560: 28.0.50; 'insert-file-contents-literally' on multibyte buffer
From: |
Lars Ingebrigtsen |
Subject: |
bug#50560: 28.0.50; 'insert-file-contents-literally' on multibyte buffers |
Date: |
Mon, 13 Sep 2021 09:10:59 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Augusto Stoffel <arstoffel@gmail.com> writes:
> I thought 'insert-file-contents-literally' literally just inserted the
> file contents, as bytes, but I noticed that in the following code
>
> (create-image
> (with-temp-buffer
> (set-buffer-multibyte nil)
> (insert-file-contents-literally "picure.jpg")
> (buffer-substring-no-properties (point-min) (point-max)))
> nil t)
>
> the call to 'set-buffer-multibyte' is really essential.
In what way? If the first byte in a binary file is #xff, inserting the
file literally in a buffer and saying `(following-char)' on the first
character in the buffer will say #xff.
But, yes, when dealing with octet streams, it's a lot less confusing if
you're using unibyte buffers (and strings).
> Is this intended? If so, I think a note in the doctring is due.
The doc string doesn't say anything about bytes, so I think that's an
interpretation on your side.
`insert-file-contents-literally' does insert "literally" -- but the byte
contents of the internal buffer structure can't be violated (emacs uses
utf-8 (plus extensions) for multibyte buffers).
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no