(subset-p): Renamed from

find-safe-coding-system-list-subset-p.
(find-coding-systems-region, find-coding-systems-string): New
functions.
(find-coding-systems-for-charsets): Renamed from
find-safe-coding-system.  This is now a helper function of the
above two.
(select-safe-coding-system): Adjusted for the above changes.

diff --git a/lisp/international/mule-cmds.el b/lisp/international/mule-cmds.el
index 509672cee6d277ec167120a0e3536c67c008efbf..a6526ff01609527beb6cb9074ebff52b59050545 100644 (file)
--- a/lisp/international/mule-cmds.el
+++ b/lisp/international/mule-cmds.el
@@ -228,7 +228,7 @@ This also sets the following values:
                 base coding-system))
     (set-default-coding-systems (or base coding-system))))
 
-(defun find-safe-coding-system-list-subset-p (list1 list2)
+(defun subset-p (list1 list2)
   "Return non-nil if all elements in LIST1 are included in LIST2.
 Comparison done with EQ."
   (catch 'tag
@@ -238,50 +238,58 @@ Comparison done with EQ."
       (setq list1 (cdr list1)))
     t))
 
-(defun find-safe-coding-system (from to)
+(defun find-coding-systems-region (from to)
   "Return a list of proper coding systems to encode a text between FROM and TO.
 All coding systems in the list can safely encode any multibyte characters
 in the text.
 
 If the text contains no multibyte charcters, return a list of a single
-element `undecided'.
+element `undecided'."
+  (find-coding-systems-for-charsets (find-charset-region from to)))
 
-Kludgy feature: if FROM is a string, the string is the target text,
-and TO is ignored."
-  (let ((charset-list (if (stringp from) (find-charset-string from)
-                       (find-charset-region from to))))
-    (if (or (null charset-list)
-           (and (= (length charset-list) 1)
-                (eq 'ascii (car charset-list))))
-       '(undecided)
-      (let ((l coding-system-list)
-           (prefered-codings
-            (mapcar (function
-                     (lambda (x)
-                       (get-charset-property x 'prefered-coding-system)))
-                    charset-list))
-           codings coding safe)
-       (while l
-         (setq coding (car l) l (cdr l))
-         (if (and (eq coding (coding-system-base coding))
-                  (setq safe (coding-system-get coding 'safe-charsets))
-                  (or (eq safe t)
-                      (find-safe-coding-system-list-subset-p
-                       charset-list safe)))
-             ;; We put the higher priority to coding systems included
-             ;; in PREFERED-CODINGS, and within them, put the higher
-             ;; priority to coding systems which support smaller
-             ;; number of charsets.
-             (let ((priority
-                    (logior (if (coding-system-get coding 'mime-charset)
-                                256 0)
-                            (if (memq coding prefered-codings) 128 0)
-                            (if (> (coding-system-type coding) 0) 64 0)
-                            (if (consp safe) (- 64 (length safe)) 0))))
-               (setq codings (cons (cons priority coding) codings)))))
-       (mapcar 'cdr
-               (sort codings (function (lambda (x y) (> (car x) (car y))))))
-       ))))
+(defun find-coding-systems-string (string)
+  "Return a list of proper coding systems to encode STRING.
+All coding systems in the list can safely encode any multibyte characters
+in STRING.
+
+If STRING contains no multibyte charcters, return a list of a single
+element `undecided'."
+  (find-coding-systems-for-charsets (find-charset-string string)))
+
+(defun find-coding-systems-for-charsets (charsets)
+  "Return a list of proper coding systems to encode characters of CHARSETS.
+CHARSETS is a list of character sets."
+  (if (or (null charsets)
+         (and (= (length charsets) 1)
+              (eq 'ascii (car charsets))))
+      '(undecided)
+    (let ((l coding-system-list)
+         (prefered-codings
+          (mapcar (function
+                   (lambda (x)
+                     (get-charset-property x 'prefered-coding-system)))
+                  charsets))
+         codings coding safe)
+      (while l
+       (setq coding (car l) l (cdr l))
+       (if (and (eq coding (coding-system-base coding))
+                (setq safe (coding-system-get coding 'safe-charsets))
+                (or (eq safe t)
+                    (subset-p charsets safe)))
+           ;; We put the higher priority to coding systems included
+           ;; in PREFERED-CODINGS, and within them, put the higher
+           ;; priority to coding systems which support smaller
+           ;; number of charsets.
+           (let ((priority
+                  (logior (if (coding-system-get coding 'mime-charset)
+                              256 0)
+                          (if (memq coding prefered-codings) 128 0)
+                          (if (> (coding-system-type coding) 0) 64 0)
+                          (if (consp safe) (- 64 (length safe)) 0))))
+             (setq codings (cons (cons priority coding) codings)))))
+      (mapcar 'cdr
+             (sort codings (function (lambda (x y) (> (car x) (car y))))))
+      )))
 
 (defun select-safe-coding-system (from to &optional default-coding-system)
   "Ask a user to select a safe coding system from candidates.
@@ -299,7 +307,9 @@ Kludgy feature: if FROM is a string, the string is the target text,
 and TO is ignored."
   (or default-coding-system
       (setq default-coding-system buffer-file-coding-system))
-  (let ((safe-coding-systems (find-safe-coding-system from to)))
+  (let ((safe-coding-systems (if (stringp from)
+                                (find-coding-systems-string from)
+                              (find-coding-systems-region from to))))
     (if (or (eq (car safe-coding-systems) 'undecided)
            (and default-coding-system
                 (memq (coding-system-base default-coding-system)