(decode-coding-region-as-inserted-from-file): New function.

1 files changed, 27 insertions, 0 deletions

diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index 909ba315b77..aa14f442bd0 100644
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -1899,6 +1899,33 @@ or a function symbol which, when called, returns such a cons cell."
                    (cons (cons regexp coding-system)
                          network-coding-system-alist)))))))
 
+(defun decode-coding-region-as-inserted-from-file (from to filename
+                                                        &optional
+                                                        visit beg end replace)
+  "Decode the region between FROM and TO as if it is read from file FILENAME.
+Optional arguments VISIT, BEG, END, and REPLACE are the same as those
+of the function `insert-file-contents'."
+  (save-excursion
+    (save-restriction
+      (narrow-to-region from to)
+      (goto-char (point-min))
+      (let ((coding coding-system-for-read))
+        (or coding
+            (setq coding (funcall set-auto-coding-function
+                                  filename (- (point-max) (point-min)))))
+        (or coding
+            (setq coding (find-operation-coding-system
+                          'insert-file-contents
+                          filename visit beg end replace)))
+        (if (coding-system-p coding)
+            (or enable-multibyte-characters
+                (setq coding
+                      (coding-system-change-text-conversion coding 'raw-text)))
+          (setq coding nil))
+        (if coding
+            (decode-coding-region (point-min) (point-max) coding))
+        (setq last-coding-system-used coding)))))
+
 (defun make-translation-table (&rest args)
   "Make a translation table from arguments.
 A translation table is a char table intended for character