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bug#20154: 25.0.50; json-encode-string is too slow for large strings
From: |
Ivan Shmakov |
Subject: |
bug#20154: 25.0.50; json-encode-string is too slow for large strings |
Date: |
Sat, 21 Mar 2015 22:20:51 +0000 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
>>>>> Dmitry Gutov <dgutov@yandex.ru> writes:
[…]
> Here's the updated definition (by the way, `json-special-chars' is
> still needed, to convert ?\n to ?n, and so on, and the performance
> hit is negligible).
Perhaps a plain vector may fit there?
> (defun json-encode-string-1 (string)
> "Return a JSON representation of STRING."
> (with-temp-buffer
> (insert string)
> (goto-char (point-min))
> ;; Skip over ASCIIish printable characters.
> (while (re-search-forward "\\([\"\\/\b\f\n\r\t]\\)\\|[^ -~]" nil t)
> (let ((c (char-before)))
> (delete-region (1- (point)) (point))
> (if (match-beginning 1)
> ;; Special JSON character (\n, \r, etc.).
> (insert "\\" (car (rassoc c json-special-chars)))
> ;; Fallback: UCS code point in \uNNNN form.
> (insert (format "\\u%04x" c)))))
> (concat "\"" (buffer-string) "\"")))
FWIW, using replace-match in the loop seem to speed up the
routine by another few percents.
(while (re-search-forward "\\([\"\\/\b\f\n\r\t]\\)\\|[^ -~]" nil t)
(let ((c (char-before)))
(replace-match
(if (match-beginning 1)
;; Special JSON character (\n, \r, etc.).
(string ?\\ (car (rassq c json-special-chars)))
;; Fallback: UCS code point in \uNNNN form.
(format "\\u%04x" c))
t t)))
[…]
--
FSF associate member #7257 http://boycottsystemd.org/ … 3013 B6A0 230E 334A
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, (continued)
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Drew Adams, 2015/03/21
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/21
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/20
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/21
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/21
- bug#20154: 25.0.50; json-encode-string is too slow for large strings,
Ivan Shmakov <=
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/21
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Ivan Shmakov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Ivan Shmakov, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Glenn Morris, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Eli Zaretskii, 2015/03/22
- bug#20154: 25.0.50; json-encode-string is too slow for large strings, Dmitry Gutov, 2015/03/22