(set-auto-coding): Name changed from

auto-file-coding-system.  The argument STRING is now a
concatination of the heading 1K-byte and the tailing 3K-byte of a
file.
(set-auto-coding-function): Set it to `set-auto-coding'.

1 files changed, 71 insertions, 25 deletions

diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index 30063dd5a9a..05631e1a1bc 100644
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -613,34 +613,80 @@ LIST is a list of coding-categories ordered by priority."
 
 ;;; FILE I/O
 
-(defun auto-file-coding-system (head-lines)
-  "Return coding system for a file which has HEAD-LINES at the head.
-HEAD-LINES is a string of the first two lines of the file.
-This checks for a -*- coding tag in the buffers's text,
-and return the specified coding system.
+(defun set-auto-coding (string)
+  "Return coding system for a file which has STRING at the head and tail.
+STRING is a concatination of the first 1K-byte and
+ the last 3K-byte of the file.
+
+It checks for a -*- coding: tag in the first one or two lines of STRING.
+If there's no coding: tag in the head, it checks local variables spec
+in the tailing 3K-byte oof STRING.
+
+The return value is the specified coding system,
+or nil if nothing specified.
 
 The variable `auto-file-coding-system' (which see) is set to this
 function by default."
-  (let ((limit (string-match "\n" head-lines))
-        (coding-system nil))
-    (if limit
-        (when (string-match "^#!" head-lines)
-          ;; If the file begins with "#!" (exec interpreter magic),
-          ;; look for coding frobs in the first two lines.  You cannot
-          ;; necessarily put them in the first line of such a file
-          ;; without screwing up the interpreter invocation.
-          (setq limit (string-match "\n" head-lines limit))
-          (or limit
-              (setq limit (length head-lines))))
-      (setq limit (length head-lines)))
-    (when (and (string-match "-\\*-[ \t]*coding:[ \t]*\\([^ ;]+\\)" head-lines)
-               (< (match-beginning 1) limit))
-      (setq coding-system
-            (intern (substring head-lines (match-beginning 1) (match-end 1))))
-      (if (coding-system-p coding-system)
-          coding-system))))
-
-(setq auto-file-coding-system-function 'auto-file-coding-system)
+  (condition-case nil
+      (let ((case-fold-search t)
+            (len (length string))
+            (limit (string-match "\n" string))
+            (coding-system nil))
+
+        ;; At first check the head.
+        (if limit
+            (when (string-match "^#!" string)
+              ;; If the file begins with "#!" (exec interpreter
+              ;; magic), look for coding frobs in the first two lines.
+              ;; You cannot necessarily put them in the first line of
+              ;; such a file without screwing up the interpreter
+              ;; invocation.
+              (setq limit (string-match "\n" string limit))
+              (or limit
+                  (setq limit len)))
+          (setq limit len))
+        (when (and (string-match "-\\*-[ \t]*coding:[ \t]*\\([^ ;]+\\)" string)
+                   (< (match-beginning 1) limit))
+          (setq coding-system
+                (intern (substring string (match-beginning 1) (match-end 1))))
+          (if (not (coding-system-p coding-system))
+              (setq coding-system nil)))
+
+        ;; If no coding system is specified in the head, check the tail.
+        (when (and (not coding-system)
+                   (let ((idx (if (> len 3000) (- len 3000) 0))
+                         start)
+                     (while (setq start (string-match "\n\^L" string idx))
+                       (setq idx (+ start 2)))
+                     (string-match
+                      "^\\(.*\\)[ \t]*Local Variables:[ \t]*\\(.*\\)$"
+                      string idx)))
+          ;; The prefix is what comes before "local variables:" in its line.
+          ;; The suffix is what comes after "local variables:" in its line.
+          (let* ((idx (1+ (match-end 0)))
+                 (prefix (regexp-quote
+                          (substring string
+                                     (match-beginning 1) (match-end 1))))
+                 (suffix (regexp-quote
+                          (substring string
+                                     (match-beginning 2) (match-end 2))))
+                 (re-coding (concat "^" prefix
+                                    "coding[ \t]*:[ \t]*\\([^ \t]+\\)[ \t]*"
+                                    suffix "$"))
+                 (re-end (concat "^" prefix "end *:[ \t]*" suffix "$"))
+                 (limit (or (string-match re-end string idx) len)))
+            (when (and (setq idx (string-match re-coding string idx))
+                       (< idx limit))
+              (setq coding-system
+                    (intern (substring string
+                                       (match-beginning 1) (match-end 1))))
+              (or (coding-system-p coding-system)
+                  (setq coding-system nil)))))
+
+        coding-system)
+    (error nil)))
+
+(setq set-auto-coding-function 'set-auto-coding)
 
 ;; Set buffer-file-coding-system of the current buffer after some text
 ;; is inserted.