(try_window_id): Use DEC_POS only for multibyte buffer.

display_text_line): Handling of a wide-column character fixed.
Make the behaviour consistent with INC_POS.

1 files changed, 68 insertions, 35 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 3f4f3099057..f088a1c462b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2520,7 +2520,7 @@ try_window_id (window)
   int selective = (INTEGERP (current_buffer->selective_display)
                    ? XINT (current_buffer->selective_display)
                    : !NILP (current_buffer->selective_display) ? -1 : 0);
-
+  int multibyte = !NILP (current_buffer->enable_multibyte_characters);
   struct position val, bp, ep, xp, pp;
   int scroll_amount = 0;
   int delta;
@@ -2600,7 +2600,10 @@ try_window_id (window)
       val.tab_offset = bp.tab_offset + bp.prevhpos - width;
       did_motion = 1;
       pos--;
-      DEC_POS (pos_byte);
+      if (multibyte)
+        DEC_POS (pos_byte);
+      else
+        pos_byte--;
     }
 
   bp.vpos = vpos;
@@ -2864,7 +2867,10 @@ try_window_id (window)
           val.hpos = xp.prevhpos - width + lmargin;
           val.tab_offset = xp.tab_offset + bp.prevhpos - width;
           pos--;
-          DEC_POS (pos_byte);
+          if (multibyte)
+            DEC_POS (pos_byte);
+          else
+            pos_byte--;
         }
 
       blank_end_of_window = 1;
@@ -3117,6 +3123,7 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
   register GLYPH *leftmargin;
   register GLYPH *p1prev;
   register GLYPH *p1start;
+  GLYPH *p1_wide_column_end = (GLYPH *) 0;
   int prevpos, prevpos_byte;
   int *charstart;
   FRAME_PTR f = XFRAME (w->frame);
@@ -3270,11 +3277,12 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
       if (left_edge->vpos > vpos
           || left_edge->hpos > 0)
         {
-          pos = left_edge->bufpos;
-          /* Since this should not be a valid multibyte character, we
-             can decrease POS by 1.  */
-          pos--;
-          pos_byte = left_edge->bytepos - 1;
+          pos = left_edge->bufpos - 1;
+          pos_byte = left_edge->bytepos;
+          if (multibyte)
+            DEC_POS (pos_byte);
+          else
+            pos_byte--;
           hpos = left_edge->prevhpos;
         }
       else
@@ -3326,6 +3334,8 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
 
   while (p1 < endp)
     {
+      int eat_following_binary_data;
+
       if (pos >= pause)
         {
           int e_t_h;
@@ -3531,6 +3541,7 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
         break;
 
       p1prev = p1;
+      p1_wide_column_end = (GLYPH *) 0;
 
       if (multibyte)
         c = STRING_CHAR_AND_LENGTH (p, limit_byte - pos_byte, len), p += len;
@@ -3712,24 +3723,32 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
       else if (len == 1)
         {
           /* C is not a multibyte character.  */
-          if (p1 >= leftmargin)
-            *p1 = (fix_glyph
-                   (f, (dp && INTEGERP (DISP_ESCAPE_GLYPH (dp))
-                        && GLYPH_CHAR_VALID_P (XINT (DISP_ESCAPE_GLYPH (dp)))
-                        ? XINT (DISP_ESCAPE_GLYPH (dp)) : '\\'),
-                    current_face)
-                   | rev_dir_bit);
-          p1++;
-          if (p1 >= leftmargin && p1 < endp)
-            *p1 = MAKE_GLYPH (f, (c >> 6) + '0', current_face) | rev_dir_bit;
-          p1++;
-          if (p1 >= leftmargin && p1 < endp)
-            *p1 = (MAKE_GLYPH (f, (7 & (c >> 3)) + '0', current_face)
-                   | rev_dir_bit);
-          p1++;
-          if (p1 >= leftmargin && p1 < endp)
-            *p1 = MAKE_GLYPH (f, (7 & c) + '0', current_face) | rev_dir_bit;
-          p1++;
+          eat_following_binary_data = multibyte && BASE_LEADING_CODE_P (c);
+          
+        label_display_binary_data:
+          do {
+            if (p1 >= leftmargin && p1 < endp)
+              *p1 = (fix_glyph
+                     (f, (dp && INTEGERP (DISP_ESCAPE_GLYPH (dp))
+                          && GLYPH_CHAR_VALID_P (XINT (DISP_ESCAPE_GLYPH (dp)))
+                          ? XINT (DISP_ESCAPE_GLYPH (dp)) : '\\'),
+                      current_face)
+                     | rev_dir_bit);
+            p1++;
+            if (p1 >= leftmargin && p1 < endp)
+              *p1 = MAKE_GLYPH (f, (c >> 6) + '0', current_face) | rev_dir_bit;
+            p1++;
+            if (p1 >= leftmargin && p1 < endp)
+              *p1 = (MAKE_GLYPH (f, (7 & (c >> 3)) + '0', current_face)
+                     | rev_dir_bit);
+            p1++;
+            if (p1 >= leftmargin && p1 < endp)
+              *p1 = MAKE_GLYPH (f, (7 & c) + '0', current_face) | rev_dir_bit;
+            p1++;
+          } while (eat_following_binary_data
+                   && (pos_byte + len) < limit_byte
+                   && ! CHAR_HEAD_P (*p)
+                   && ((c = *p++), len++));
         }
       else
         {
@@ -3746,6 +3765,17 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
                 *p1 = g, g |= GLYPH_MASK_PADDING;
               p1++;
             }
+
+          p1_wide_column_end = p1;
+          /* Check if binary data follows it.  */
+          if (pos_byte + len < limit_byte
+              && ! CHAR_HEAD_P (*p))
+            {
+              eat_following_binary_data = 1;
+              c = *p++;
+              len++;
+              goto label_display_binary_data;
+            }
         }
 
       prevpos = pos;
@@ -3811,17 +3841,17 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
           pos = prevpos;
           pos_byte = prevpos_byte;
 
-          if (len == 1)
-            /* C is not a multi-byte character.  We can break it and
-               start from the middle column in the next line.  So,
-               adjust VAL.HPOS to skip the columns output on this
-               line.  */
+          if (p1_wide_column_end < endp)
+            /* As ENDP is not in the middle of wide-column character,
+               we can break the line at ENDP and start from the middle
+               column in the next line.  So, adjust VAL.HPOS to skip
+               the columns output on this line.  */
             val.hpos += p1prev - endp;
           else
             {
-              /* C is a multibyte character.  Since we can't broke it
-                 in the middle, the whole character should be driven
-                 into the next line.  */
+              /* We displayed a wide-column character at around ENDP.
+                 Since we can't broke it in the middle, the whole
+                 character should be driven into the next line.  */
               /* As the result, the actual columns occupied by the
                  text on this line is less than WIDTH.  VAL.TAB_OFFSET
                  must be adjusted.  */
@@ -3897,7 +3927,10 @@ display_text_line (w, start, start_byte, vpos, hpos, taboffset, ovstr_done)
               *p1++ = fix_glyph (f, continuer, 0);
               val.vpos = 0;
               lastpos--;
-              DEC_POS (lastpos_byte);
+              if (multibyte)
+                DEC_POS (lastpos_byte);
+              else
+                lastpos_byte--;
               val.tab_offset = taboffset + width;
             }
         }