1 files changed, 41 insertions, 20 deletions

diff --git a/src/coding.c b/src/coding.c
index 5bfcacc1e17..ee5fdf25fc2 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -623,38 +623,59 @@ detect_coding_iso2022 (src, src_end)
           if (src >= src_end)
             break;
           c = *src++;
-          if (src < src_end
-              && ((c >= '(' && c <= '/')
-                  || c == '$' && ((*src >= '(' && *src <= '/')
-                                  || (*src >= '@' && *src <= 'B'))))
+          if ((c >= '(' && c <= '/'))
             {
-              /* Valid designation sequence.  */
-              if (c == ')' || (c == '$' && *src == ')'))
+              /* Designation sequence for a charset of dimension 1.  */
+              if (src >= src_end)
+                break;
+              c = *src++;
+              if (c < ' ' || c >= 0x80)
+                /* Invalid designation sequence.  */
+                return 0;
+            }
+          else if (c == '$')
+            {
+              /* Designation sequence for a charset of dimension 2.  */
+              if (src >= src_end)
+                break;
+              c = *src++;
+              if (c >= '@' && c <= 'B')
+                /* Designation for JISX0208.1978, GB2312, or JISX0208.  */
+                ;
+              else if (c >= '(' && c <= '/')
                 {
-                  g1 = 1;
-                  mask &= ~(CODING_CATEGORY_MASK_ISO_7
-                            | CODING_CATEGORY_MASK_ISO_7_ELSE);
+                  if (src >= src_end)
+                    break;
+                  c = *src++;
+                  if (c < ' ' || c >= 0x80)
+                    /* Invalid designation sequence.  */
+                    return 0;
                 }
-              src++;
-              break;
+              else
+                /* Invalid designation sequence.  */
+                return 0;
             }
           else if (c == 'N' || c == 'O' || c == 'n' || c == 'o')
+            /* Locking shift.  */
             mask &= (CODING_CATEGORY_MASK_ISO_7_ELSE
                      | CODING_CATEGORY_MASK_ISO_8_ELSE);
+          else if (c == '0' || c == '1' || c == '2')
+            /* Start/end composition.  */
+            ;
+          else
+            /* Invalid escape sequence.  */
+            return 0;
           break;
 
         case ISO_CODE_SO:
-          if (g1)
-            mask &= (CODING_CATEGORY_MASK_ISO_7_ELSE
-                     | CODING_CATEGORY_MASK_ISO_8_ELSE);
+          mask &= (CODING_CATEGORY_MASK_ISO_7_ELSE
+                   | CODING_CATEGORY_MASK_ISO_8_ELSE);
           break;
           
         case ISO_CODE_CSI:
         case ISO_CODE_SS2:
         case ISO_CODE_SS3:
-          mask &= ~(CODING_CATEGORY_MASK_ISO_7
-                    | CODING_CATEGORY_MASK_ISO_7_ELSE);
-          break;
+          return CODING_CATEGORY_MASK_ISO_8_ELSE;
 
         default:
           if (c < 0x80)
@@ -3001,10 +3022,10 @@ The value of property should be a vector of length 5.")
 
 DEFUN ("detect-coding-region", Fdetect_coding_region, Sdetect_coding_region,
        2, 2, 0,
-  "Detect coding-system of the text in the region between START and END.\n\
-Return a list of possible coding-systems ordered by priority.\n\
+  "Detect coding system of the text in the region between START and END.\n\
+Return a list of possible coding systems ordered by priority.\n\
 If only ASCII characters are found, it returns `undecided'\n\
- or its subsidiary coding-system according to a detected end-of-line format.")
+ or its subsidiary coding system according to a detected end-of-line format.")
   (b, e)
      Lisp_Object b, e;
 {