From: storm@cua.dk (Kim F. Storm)
Cc: emacs-devel@gnu.org
Subject: Re: [HELP] (bug?) Saving a buffer without any conversion?
Date: 15 Jan 2003 12:02:40 +0100 [thread overview]
Message-ID: <5xk7h67k1b.fsf@kfs2.cua.dk> (raw)
In-Reply-To: <200301150116.KAA09223@etlken.m17n.org>
Kenichi Handa <handa@m17n.org> writes:
> In article <87fzrxszs8.fsf@lexx.delysid.org>, Mario Lang <mlang@delysid.org> writes:
> > We're receiving binary content via a network process. After the
> > transfer is complete, this buffer should be saved to a file.
>
> > The effect I'm having is that we receive 1372422 bytes via the process
> > filter function STRING argument, and after insertion into a buffer,
> > we have a buffer with buffer-size 1372422, but after calling (save-buffer)
> > we get this:
>
> > -rw-r--r-- 1 root root 1865264 Jan 13 18:35 blah28.mp3
>
> > I'm using:
>
> > (set-process-coding-system proc 'binary 'binary)
> > (set-buffer-file-coding-system 'no-conversion t)
>
> storm@cua.dk (Kim F. Storm) writes:
> > I have looked at Mario's data before sending it to emacs and after
> > emacs has written it to a file.
>
> > It seems that every byte in the range 0xa0 .. 0xff that were in the
> > original file is prefixed with an 0x81 byte in the file containing the
> > received data. To me, that looks like the internal multi-byte
> > representation for the binary data.
>
> No. 0x81 means that 0xA0..0xFF are decoded as Latin-1
> chars. That's why raw-text and no-conversion write out 0x81
> as is to a file. And that means that somehow:
> (set-process-coding-system proc 'binary 'binary)
> didn't take effect. When did you execute this function? It
> should be before accepting any data from the process
> (usually just after start-process or open-network-stream).
>
Mario's code is using open-network-stream, and the set-process-... things are
done immediately after creating the process (IIRC).
He uses a process filter to "insert" the received strings to the
buffer like this [approximately]:
(defun filter (proc string)
(with-current-buffer (process-buffer proc)
(insert string)))
Here is a small, selfcontained test case.
If you eval the following form, wait a few seconds, the result is
"BUFFER=10 FILE=20"
meaning that the temp.out buffer is 10 "bytes", but the written
file is 20 "bytes".
Adding the "set-buffer-multibyte" line produces the right result.
(let (proc proc2)
(if (get-buffer "temp.out")
(kill-buffer "temp.out"))
(save-excursion
(set-buffer (get-buffer-create "temp.out"))
(set-buffer-file-coding-system 'binary)
(erase-buffer)
;; (set-buffer-multibyte nil)
)
(setq proc (make-network-process
:server t
:name "temp"
:buffer "temp.out"
:service 2000
:sentinel nil
:filter (lambda (proc string)
(with-current-buffer (get-buffer "temp.out")
(insert string)))
:coding 'binary))
(setq proc2 (make-network-process
:name "temp2"
:buffer nil
:service 2000
:host 'local
:coding 'binary))
(sleep-for 1)
(process-send-string proc2 (make-string 10 255))
(sleep-for 1)
(delete-process proc2)
(save-excursion
(set-buffer (get-buffer "temp.out"))
(let (require-final-newline)
(delete-file "/tmp/temp.out")
(write-file "/tmp/temp.out")))
(sleep-for 1)
(delete-process proc)
(format "BUFFER=%d FILE=%d" (buffer-size (get-buffer "temp.out"))
(nth 7 (file-attributes "/tmp/temp.out")))
)
--
Kim F. Storm <storm@cua.dk> http://www.cua.dk
next prev parent reply other threads:[~2003-01-15 11:02 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-01-13 17:52 [HELP] (bug?) Saving a buffer without any conversion? Mario Lang
2003-01-14 1:00 ` Kim F. Storm
2003-01-14 6:06 ` Eli Zaretskii
2003-01-14 6:46 ` Mario Lang
2003-01-14 18:37 ` Eli Zaretskii
2003-01-14 16:19 ` Stefan Monnier
2003-01-15 1:16 ` Kenichi Handa
2003-01-15 11:02 ` Kim F. Storm [this message]
2003-01-15 10:59 ` Kenichi Handa
2003-01-15 13:27 ` Kim F. Storm
2003-01-15 16:30 ` Eli Zaretskii
2003-01-16 22:52 ` Kim F. Storm
2003-01-17 2:35 ` Kenichi Handa
2003-01-16 1:18 ` Kenichi Handa
2003-01-17 9:23 ` Richard Stallman
2003-01-17 11:07 ` Kenichi Handa
2003-01-15 16:59 ` Mario Lang
2003-01-15 23:27 ` Richard Stallman
2003-01-16 6:45 ` Kenichi Handa
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