(latexenc-find-file-coding-system): Avoid `re-search-forward' when

looking for input encoding because of speed and safety.  Better
regular expressions for recognizing input encoding.  Limit a search
for TeX-master/tex-main-file to the local variable section.

1 files changed, 21 insertions, 13 deletions

diff --git a/lisp/international/latexenc.el b/lisp/international/latexenc.el
index 1fd04b55919..39acbb33dfd 100644
--- a/lisp/international/latexenc.el
+++ b/lisp/international/latexenc.el
@@ -120,24 +120,32 @@ coding system names is determined from `latex-inputenc-coding-alist'."
       (save-excursion
         ;; try to find the coding system in this file
         (goto-char (point-min))
-        (if (or
-             (re-search-forward "^[^%\n]*\\\\inputencoding{\\(.*\\)}" nil t)
-             (re-search-forward "^[^%\n]*\\\\usepackage\\[\\(.*\\)\\]{inputenc}" nil t))
-            (let* ((match (match-string 1))
-                   (sym (intern match)))
-              (when (latexenc-inputenc-to-coding-system match)
-                (setq sym (latexenc-inputenc-to-coding-system match))
-                (when (coding-system-p sym)
-                  sym
-                  (if (and (require 'code-pages nil t) (coding-system-p sym))
-                      sym
-                    'undecided))))
+        (if (catch 'cs
+              (let ((case-fold-search nil))
+                (while (search-forward "inputenc" nil t)
+                  (goto-char (match-beginning 0))
+                  (beginning-of-line)
+                  (if (or (looking-at "[^%\n]*\\\\usepackage\\[\\([^]]*\\)\\]{\\([^}]*,\\)?inputenc\\(,[^}]*\\)?}")
+                          (looking-at "[^%\n]*\\\\inputencoding{\\([^}]*\\)}"))
+                      (throw 'cs t)
+                    (goto-char (match-end 0))))))
+            (let* ((match (match-string 1))
+                   (sym (intern match)))
+              (when (latexenc-inputenc-to-coding-system match)
+                (setq sym (latexenc-inputenc-to-coding-system match)))
+              (when (coding-system-p sym)
+                sym
+                (if (and (require 'code-pages nil t) (coding-system-p sym))
+                    sym
+                  'undecided)))
           ;; else try to find it in the master/main file
           (let (latexenc-main-file)
             ;; is there a TeX-master or tex-main-file in the local variable section
             (unless latexenc-dont-use-TeX-master-flag
               (goto-char (point-max))
-              (when (re-search-backward "^%+ *\\(TeX-master\\|tex-main-file\\): *\"\\(.+\\)\"" nil t)
+              (search-backward "\n\^L" (max (- (point-max) 3000) (point-min)) 'move)
+              (search-forward "Local Variables:" nil t)
+              (when (re-search-forward "^%+ *\\(TeX-master\\|tex-main-file\\): *\"\\(.+\\)\"" nil t)
                 (let ((file (concat (file-name-directory (nth 1 arg-list)) (match-string 2))))
                   (if (file-exists-p file)
                       (setq latexenc-main-file file)