(encode_coding_iso2022): Write out invalid multibyte

forms in a buffer as is.
(detect_coding_mask): If ISO_CODE_CSI appears in an invalid
sequence, ignore it.

1 files changed, 46 insertions, 6 deletions

diff --git a/src/coding.c b/src/coding.c
index bd824bceee2..2ebf0a2eade 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -1495,12 +1495,26 @@ encode_coding_iso2022 (coding, source, destination,
 
         case EMACS_leading_code_2:
           ONE_MORE_BYTE (c2);
-          ENCODE_ISO_CHARACTER (c1, c2, /* dummy */ c3);
+          if (c2 < 0xA0)
+            {
+              /* invalid sequence */
+              *dst++ = c1;
+              *dst++ = c2;
+            }
+          else
+            ENCODE_ISO_CHARACTER (c1, c2, /* dummy */ c3);
           break;
 
         case EMACS_leading_code_3:
           TWO_MORE_BYTES (c2, c3);
-          if (c1 < LEADING_CODE_PRIVATE_11)
+          if (c2 < 0xA0 || c3 < 0xA0)
+            {
+              /* invalid sequence */
+              *dst++ = c1;
+              *dst++ = c2;
+              *dst++ = c3;
+            }
+          else if (c1 < LEADING_CODE_PRIVATE_11)
             ENCODE_ISO_CHARACTER (c1, c2, c3);
           else
             ENCODE_ISO_CHARACTER (c2, c3, /* dummy */ c4);
@@ -1508,12 +1522,27 @@ encode_coding_iso2022 (coding, source, destination,
 
         case EMACS_leading_code_4:
           THREE_MORE_BYTES (c2, c3, c4);
-          ENCODE_ISO_CHARACTER (c2, c3, c4);
+          if (c2 < 0xA0 || c3 < 0xA0 || c4 < 0xA0)
+            {
+              /* invalid sequence */
+              *dst++ = c1;
+              *dst++ = c2;
+              *dst++ = c3;
+              *dst++ = c4;
+            }
+          else
+            ENCODE_ISO_CHARACTER (c2, c3, c4);
           break;
 
         case EMACS_leading_code_composition:
-          ONE_MORE_BYTE (c1);
-          if (c1 == 0xFF)
+          ONE_MORE_BYTE (c2);
+          if (c2 < 0xA0)
+            {
+              /* invalid sequence */
+              *dst++ = c1;
+              *dst++ = c2;
+            }
+          else if (c2 == 0xFF)
             {
               coding->composing = COMPOSING_WITH_RULE_HEAD;
               ENCODE_COMPOSITION_WITH_RULE_START;
@@ -2555,7 +2584,7 @@ detect_coding_mask (src, src_bytes)
         /* No valid ISO2022 code follows C.  Try again.  */
         goto label_loop_detect_coding;
     }
-  else if (c == ISO_CODE_SS2 || c == ISO_CODE_SS3 || c == ISO_CODE_CSI)
+  else if (c == ISO_CODE_SS2 || c == ISO_CODE_SS3)
     /* C is an ISO2022 specific control code of C1,
        or the first byte of SJIS's 2-byte character code,
        or a leading code of Emacs.  */
@@ -2563,6 +2592,17 @@ detect_coding_mask (src, src_bytes)
             | detect_coding_sjis (src, src_end)
             | detect_coding_emacs_mule (src, src_end));
 
+  else if (c == ISO_CODE_CSI
+           && (src < src_end
+              && (*src == ']'
+                  || (src + 1 < src_end
+                      && src[1] == ']'
+                      && (*src == '0' || *src == '1' || *src == '2')))))
+    /* C is an ISO2022's control-sequence-introducer.  */
+    mask = (detect_coding_iso2022 (src, src_end)
+            | detect_coding_sjis (src, src_end)
+            | detect_coding_emacs_mule (src, src_end));
+    
   else if (c < 0xA0)
     /* C is the first byte of SJIS character code,
        or a leading-code of Emacs.  */