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* lisp/info.el: Cleanup bytepos/charpos issues

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* lisp/international/mule-util.el: Use lexical-binding.
(filepos-to-bufferpos): New function.
* lisp/info.el (Info-find-in-tag-table-1): Use 0-based file positions.
(Info-find-node-2): Use filepos-to-bufferpos (bug#20704).
(Info-read-subfile, Info-search): Use 0-based file positions.
This commit is contained in:
Stefan Monnier 2015-06-15 18:48:08 -04:00
parent 4c4a329cf4
commit b95f53f038
3 changed files with 63 additions and 27 deletions
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2
etc/NEWS
View file

@ -851,6 +851,8 @@ behavior, set `diff-switches' to `-c'.
* Lisp Changes in Emacs 25.1
** New function `filepos-to-bufferpos'.
** The default value of `load-read-function' is now `read'.
** New hook `pre-redisplay-functions', a bit easier to use than pre-redisplay-function.

41
lisp/info.el
View file

@ -1009,7 +1009,7 @@ REGEXP is a regular expression matching nodes or references. Its first
group should match `Node:' or `Ref:'.
CASE-FOLD t means search for a case-insensitive match.
If a match was found, value is a list (FOUND-ANCHOR POS MODE), where
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the position
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the file position
where the match was found, and MODE is `major-mode' of the buffer in
which the match was found."
(let ((case-fold-search case-fold))
@ -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)))
(read (current-buffer))
major-mode)))))
(defun Info-find-in-tag-table (marker regexp &optional strict-case)
@ -1029,7 +1029,7 @@ MARKER specifies the buffer and position to start searching at.
REGEXP is a regular expression matching nodes or references. Its first
group should match `Node:' or `Ref:'.
If a match was found, value is a list (FOUND-ANCHOR POS MODE), where
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the position
FOUND-ANCHOR is non-nil if a `Ref:' was matched, POS is the file position
where the match was found, and MODE is `major-mode' of the buffer in
which the match was found.
This function tries to find a case-sensitive match first, then a
@ -1187,15 +1187,18 @@ is non-nil)."
(when found
;; FOUND is (ANCHOR POS MODE).
(setq guesspos (nth 1 found))
(let ((filepos (nth 1 found))) ;File position in bytes.
;; If this is an indirect file, determine which
;; file really holds this node and read it in.
(unless (eq (nth 2 found) 'Info-mode)
;; Note that the current buffer must be the
;; *info* buffer on entry to
;; Info-read-subfile. Thus the hackery above.
(setq guesspos (Info-read-subfile guesspos)))
;; If this is an indirect file, determine which
;; file really holds this node and read it in.
(unless (eq (nth 2 found) 'Info-mode)
;; Note that the current buffer must be the
;; *info* buffer on entry to
;; Info-read-subfile. Thus the hackery above.
(setq filepos (Info-read-subfile filepos)))
(setq guesspos
(filepos-to-bufferpos filepos 'approximate)))
;; Handle anchor
(when (nth 0 found)
@ -1203,8 +1206,7 @@ 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
@ -1506,7 +1508,7 @@ is non-nil)."
;; Note that on entry to this function the current-buffer must be the
;; *info* buffer; not the info tags buffer.
(defun Info-read-subfile (nodepos)
;; NODEPOS is either a position (in the Info file as a whole,
;; NODEPOS is either a position in bytes (in the Info file as a whole,
;; not relative to a subfile) or the name of a subfile.
(let (lastfilepos
lastfilename)
@ -1523,7 +1525,7 @@ is non-nil)."
thisfilepos thisfilename)
(search-forward ": ")
(setq thisfilename (buffer-substring beg (- (point) 2)))
(setq thisfilepos (+ (point-min) (read (current-buffer))))
(setq thisfilepos (read (current-buffer)))
;; 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."
@ -2013,10 +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)))
(match-string-no-properties 1))
list))
(push (cons (read (current-buffer))
(match-string-no-properties 1))
list)
(goto-char (if backward
(1- (match-beginning 0))
(1+ (match-end 0)))))

47
lisp/international/mule-util.el
View file

@ -1,4 +1,4 @@
;;; mule-util.el --- utility functions for multilingual environment (mule)
;;; mule-util.el --- utility functions for multilingual environment (mule) -*- lexical-binding:t -*-
;; Copyright (C) 1997-1998, 2000-2015 Free Software Foundation, Inc.
;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
@ -30,8 +30,7 @@
;;; Code:
;;; String manipulations while paying attention to multibyte
;;; characters.
;;; String manipulations while paying attention to multibyte characters.
;;;###autoload
(defsubst string-to-list (string)
@ -49,7 +48,6 @@
(if (integerp obj)
(aset string idx obj)
(let ((len1 (length obj))
(len2 (length string))
(i 0))
(while (< i len1)
(aset string (+ idx i) (aref obj i))
@ -90,7 +88,6 @@ defaults to `truncate-string-ellipsis'."
(setq ellipsis truncate-string-ellipsis))
(let ((str-len (length str))
(str-width (string-width str))
(ellipsis-len (if ellipsis (length ellipsis) 0))
(ellipsis-width (if ellipsis (string-width ellipsis) 0))
(idx 0)
(column 0)
@ -129,8 +126,8 @@ defaults to `truncate-string-ellipsis'."
tail-padding ellipsis))))
;;; Nested alist handler. Nested alist is alist whose elements are
;;; also nested alist.
;;; Nested alist handler.
;; Nested alist is alist whose elements are also nested alist.
;;;###autoload
(defsubst nested-alist-p (obj)
@ -313,6 +310,42 @@ 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 (0-based) 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 type
(`utf-8
(when (coding-system-get coding-system :bom)
(setq byte (max 0 (- byte 3))))
(let (pos lines (eol-offset 0))
(while
(progn
(setq pos (byte-to-position (+ pm byte (- eol-offset))))
(setq lines (1- (line-number-at-pos pos)))
(not (= lines eol-offset)))
(setq eol-offset (+ eol-offset lines)))
pos))
;; FIXME: What if it's a 2-byte charset? Are there such beasts?
(`charset (+ pm byte))
(_
(pcase quality
(`approximate (+ pm (byte-to-position byte)))
;; (`exact ...)
)))))
(provide 'mule-util)