Converting UTF-8 strings to hex in Emacs

Converting UTF-8 strings to hex in Emacs

[白い熊]

Hi:

I'm looking for the Emacs way to convert UTF-8 strings to Hex, so they
can be sent as hex codes to modem AT commands.

For interactive mode hexl-mode lets you view strings and see their
representation, however I need a way to do this in elisp, i.e. pass the
UTF-8 string and receive back its hex representation.

There's uni2ascii which does this, and I can call it via a call-process,
however would like to do it in elisp.

Anyone know how?
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白い熊

Re: Converting UTF-8 strings to hex in Emacs

[Andreas Schwab]

白い熊 <emacs-devel_gnu.org@sumou.com> writes:

> For interactive mode hexl-mode lets you view strings and see their
> representation, however I need a way to do this in elisp, i.e. pass the
> UTF-8 string and receive back its hex representation.

(defun uni2ascii (s)
  (mapconcat (lambda (c) (format "%02X" c))
             (encode-coding-string s 'utf-8) ""))

Andreas.

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Re: Converting UTF-8 strings to hex in Emacs

[Harald Hanche-Olsen]

+ 白い熊 <emacs-devel_gnu.org@sumou.com>:

> I'm looking for the Emacs way to convert UTF-8 strings to Hex, so they
> can be sent as hex codes to modem AT commands.

This is the emacs developer list; I think such questions are not too
welcome here. Still, I'll risk the ire of the regulars by responding.

> There's uni2ascii which does this, and I can call it via a call-process,
> however would like to do it in elisp.

Something along the lines of

(defun string-to-numeric (string)
  (let (nums)
    (dotimes (n (length string) (apply #'concat (nreverse nums)))
      (setq nums (cons (format "%d;" (aref string n))
		       nums)))))

might work; you'll have to adjust the format string to give the
desired format (I haven't the foggiest notion what uni2ascii
produces). Warning: This only works on modern emacsen for which
unicode is the internal encoding. for compatibility with older ones,
an extra function call will be needed (but I don't know which).

- Harald