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bug#20704: info.el bug fix; Interprets Info format wrongly
From: |
Stefan Monnier |
Subject: |
bug#20704: info.el bug fix; Interprets Info format wrongly |
Date: |
Wed, 10 Jun 2015 13:50:29 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
> Using byte-to-position would make things worse for Latin-1 and the likes.
There's also the problem of EOL encoding, but I'll just ignore it for now.
Could someone test the patch below?
Stefan
diff --git a/lisp/info.el b/lisp/info.el
index 9602337..0de7f1e 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -1020,7 +1020,7 @@ which the match was found."
(beginning-of-line)
(when (re-search-forward regexp nil t)
(list (string-equal "Ref:" (match-string 1))
- (+ (point-min) (read (current-buffer)))
+ (filepos-to-bufferpos (read (current-buffer)) 'approximate)
major-mode)))))
(defun Info-find-in-tag-table (marker regexp &optional strict-case)
@@ -1187,7 +1187,8 @@ is non-nil)."
(when found
;; FOUND is (ANCHOR POS MODE).
- (setq guesspos (nth 1 found))
+ (setq guesspos (filepos-to-bufferpos (nth 1 found)
+ 'approximate))
;; If this is an indirect file, determine which
;; file really holds this node and read it in.
@@ -1203,8 +1204,7 @@ is non-nil)."
(throw 'foo t)))))
;; Else we may have a node, which we search for:
- (goto-char (max (point-min)
- (- (byte-to-position guesspos) 1000)))
+ (goto-char (max (point-min) (- guesspos 1000)))
;; Now search from our advised position (or from beg of
;; buffer) to find the actual node. First, check
@@ -1523,7 +1523,9 @@ is non-nil)."
thisfilepos thisfilename)
(search-forward ": ")
(setq thisfilename (buffer-substring beg (- (point) 2)))
- (setq thisfilepos (+ (point-min) (read (current-buffer))))
+ (setq thisfilepos
+ (filepos-to-bufferpos (read (current-buffer))
+ 'approximate))
;; read in version 19 stops at the end of number.
;; Advance to the next line.
(forward-line 1)
@@ -1554,7 +1556,7 @@ is non-nil)."
;; Don't add the length of the skipped summary segment to
;; the value returned to `Info-find-node-2'. (Bug#14125)
(if (numberp nodepos)
- (+ (- nodepos lastfilepos) (point-min)))))
+ (- nodepos lastfilepos))))
(defun Info-unescape-quotes (value)
"Unescape double quotes and backslashes in VALUE."
@@ -2013,8 +2015,9 @@ If DIRECTION is `backward', search in the reverse
direction."
(re-search-backward "\\(^.*\\): [0-9]+$")
(re-search-forward "\\(^.*\\): [0-9]+$"))
(goto-char (+ (match-end 1) 2))
- (setq list (cons (cons (+ (point-min)
- (read (current-buffer)))
+ (setq list (cons (cons (filepos-to-bufferpos
+ (read (current-buffer))
+ 'approximate)
(match-string-no-properties 1))
list))
(goto-char (if backward
diff --git a/lisp/international/mule-util.el b/lisp/international/mule-util.el
index eae787b..1f7df0b 100644
--- a/lisp/international/mule-util.el
+++ b/lisp/international/mule-util.el
@@ -313,6 +313,35 @@ per-character basis, this may not be accurate."
(throw 'tag3 charset)))
charset-list)
nil)))))))))
+
+;;;###autoload
+(defun filepos-to-bufferpos (byte &optional quality coding-system)
+ "Try to return the buffer position corresponding to a particular file
position.
+The file position is given as a BYTE count.
+The function presumes the file is encoded with CODING-SYSTEM, which defaults
+to `buffer-file-coding-system'.
+QUALITY can be:
+ `approximate', in which case we may cut some corners to avoid
+ excessive work.
+ nil, in which case we may return nil rather than an approximation."
+ ;; `exact', in which case we may end up re-(en|de)coding a large
+ ;; part of the file.
+ (unless coding-system (setq coding-system buffer-file-coding-system))
+ (let ((eol (coding-system-eol-type coding-system))
+ (type (coding-system-type coding-system))
+ (pm (save-restriction (widen) (point-min))))
+ (pcase (cons type eol)
+ (`(utf-8 . ,(or 0 2))
+ (let ((bom-offset (coding-system-get coding-system :bom)))
+ (byte-to-position
+ (+ pm (max 0 (- byte (if bom-offset 3 0)))))))
+ ;; FIXME: What if it's a 2-byte charset? Are there such beasts?
+ (`(charset . ,(or 0 2)) (+ pm byte))
+ (_
+ (pcase quality
+ (`approximate (+ pm (byte-to-position byte)))
+ ;; (`exact ...)
+ )))))
(provide 'mule-util)