(MULTIBYTE_BYTES_WIDTH): New macro.

(current_column_1): Don't follow a display table for a heading
byte of a multibyte character.  Use the macro
MULTIBYTE_BYTES_WIDTH.
(Fmove_to_column): Likewise.
(compute_motion): Likewise.  Handling of wide-column character
fixed.

1 files changed, 95 insertions, 107 deletions

diff --git a/src/indent.c b/src/indent.c
index 28a661dd9f1..733272ee97b 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -266,6 +266,67 @@ skip_invisible (pos, next_boundary_p, to, window)
   return pos;
 }
 
+/* Set variables WIDTH and BYTES for a multibyte sequence starting at P.
+
+   C is *P which should satisfy `BASE_LEADING_CODE_P (c)'.
+
+   DP is a display table or NULL.
+
+   This macro is used in current_column_1, Fmove_to_column, and
+   compute_motion.  */
+
+#define MULTIBYTE_BYTES_WIDTH(p, c, dp)                                 \
+  do {                                                                  \
+    unsigned char *pend = p + 1;                                        \
+                                                                        \
+    wide_column = 0;                                                    \
+    while (! CHAR_HEAD_P (*pend)) pend++;                               \
+                                                                        \
+    if (c == LEADING_CODE_COMPOSITION)                                  \
+      {                                                                 \
+        int id = str_cmpchar_id (p, pend - p);                          \
+        int ch = MAKE_COMPOSITE_CHAR (id);                              \
+                                                                        \
+        if (id >= 0)                                                    \
+          {                                                             \
+            bytes = cmpchar_table[id]->len;                             \
+            if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, ch)))         \
+              width = XVECTOR (DISP_CHAR_VECTOR (dp, ch))->size;        \
+            else                                                        \
+              wide_column = width = cmpchar_table[id]->width;           \
+          }                                                             \
+        else                                                            \
+          {                                                             \
+            bytes = 1;                                                  \
+            width = 4;                                                  \
+          }                                                             \
+      }                                                                 \
+    else                                                                \
+      {                                                                 \
+        bytes = BYTES_BY_CHAR_HEAD (c);                                 \
+        if (bytes >= 2 && bytes <= pend - p)                            \
+          {                                                             \
+            int ch;                                                     \
+                                                                        \
+            if (dp && (ch = STRING_CHAR (p, bytes),                     \
+                       VECTORP (DISP_CHAR_VECTOR (dp, ch))))            \
+              width = XVECTOR (DISP_CHAR_VECTOR (dp, ch))->size;        \
+            else                                                        \
+              wide_column = width = WIDTH_BY_CHAR_HEAD (c);             \
+          }                                                             \
+        else                                                            \
+          {                                                             \
+            bytes = 1;                                                  \
+            width = 4;                                                  \
+          }                                                             \
+      }                                                                 \
+    if (p + bytes < pend)                                               \
+      {                                                                 \
+        width += 4 * (pend - (p + bytes));                              \
+        bytes = pend - p;                                               \
+      }                                                                 \
+  } while (0)
+
 DEFUN ("current-column", Fcurrent_column, Scurrent_column, 0, 0, 0,
   "Return the horizontal position of point.  Beginning of line is column 0.\n\
 This is calculated by adding together the widths of all the displayed\n\
@@ -439,7 +500,9 @@ current_column_1 ()
         }
 
       c = FETCH_BYTE (scan_byte);
-      if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
+      if (dp != 0
+          && ! (multibyte && BASE_LEADING_CODE_P (c))
+          && VECTORP (DISP_CHAR_VECTOR (dp, c)))
         {
           col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
           scan++;
@@ -460,42 +523,14 @@ current_column_1 ()
         }
       else if (multibyte && BASE_LEADING_CODE_P (c))
         {
-          scan_byte--;
-          /* Start of multi-byte form.  */
-          if (c == LEADING_CODE_COMPOSITION)
-            {
-              unsigned char *ptr = BYTE_POS_ADDR (scan_byte);
+          unsigned char *ptr;
+          int bytes, width, wide_column;
 
-              int cmpchar_id
-                = str_cmpchar_id (ptr, next_boundary_byte - scan_byte);
-              if (cmpchar_id >= 0)
-                {
-                  scan_byte += cmpchar_table[cmpchar_id]->len;
-                  col += cmpchar_table[cmpchar_id]->width;
-                }
-              else
-                {               /* invalid composite character */
-                  scan_byte++;
-                  col += 4;
-                }
-            }
-          else
-            {
-              /* Here, we check that the following bytes are valid
-                 constituents of multi-byte form.  */
-              int len = BYTES_BY_CHAR_HEAD (c), i;
-
-              for (i = 1, scan_byte++; i < len; i++, scan_byte++)
-                /* We don't need range checking for PTR because there
-                   are anchors (`\0') at GAP and Z.  */
-                if (CHAR_HEAD_P (FETCH_BYTE (scan_byte)))
-                  break;
-
-              if (i < len)
-                col += 4, scan_byte -= i - 1;
-              else
-                col += WIDTH_BY_CHAR_HEAD (c);
-            }
+          scan_byte--;
+          ptr = BYTE_POS_ADDR (scan_byte);
+          MULTIBYTE_BYTES_WIDTH (ptr, c, dp);
+          scan_byte += bytes;
+          col += width;
         }
       else if (ctl_arrow && (c < 040 || c == 0177))
         col += 2;
@@ -838,7 +873,9 @@ The return value is the current column.")
         break;
 
       c = FETCH_BYTE (pos_byte);
-      if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
+      if (dp != 0
+          && ! (multibyte && BASE_LEADING_CODE_P (c))
+          && VECTORP (DISP_CHAR_VECTOR (dp, c)))
         {
           col += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
           pos_byte++;
@@ -867,41 +904,13 @@ The return value is the current column.")
         {
           /* Start of multi-byte form.  */
           unsigned char *ptr;
+          int bytes, width, wide_column;
 
-          pos_byte--;           /* rewind to the character head */
+          pos_byte--;
           ptr = BYTE_POS_ADDR (pos_byte);
-          if (c == LEADING_CODE_COMPOSITION)
-            {
-              int cmpchar_id = str_cmpchar_id (ptr, end_byte - pos_byte);
-
-              if (cmpchar_id >= 0)
-                {
-                  col += cmpchar_table[cmpchar_id]->width;
-                  pos_byte += cmpchar_table[cmpchar_id]->len;
-                }
-              else
-                {               /* invalid composite character */
-                  col += 4;
-                  pos_byte++;
-                }
-            }
-          else
-            {
-              /* Here, we check that the following bytes are valid
-                 constituents of multi-byte form.  */
-              int len = BYTES_BY_CHAR_HEAD (c), i;
-
-              for (i = 1, ptr++; i < len; i++, ptr++)
-                /* We don't need range checking for PTR because there
-                   are anchors (`\0') both at GPT and Z.  */
-                if (CHAR_HEAD_P (*ptr))
-                  break;
-
-              if (i < len)
-                col += 4, pos_byte++;
-              else
-                col += WIDTH_BY_CHAR_HEAD (c), pos_byte += i;
-            }
+          MULTIBYTE_BYTES_WIDTH (ptr, c, dp);
+          pos_byte += bytes;
+          col += width;
         }
       else
         col += 4;
@@ -1046,8 +1055,8 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
   Lisp_Object window;
 
   int multibyte = !NILP (current_buffer->enable_multibyte_characters);
-  int wide_column = 0;          /* Set to 1 when a previous character
-                                   is wide-colomn.  */
+  int wide_column_end_hpos = 0; /* Horizontal position at the end of
+                                   last wide-column character.  */
   int prev_pos;                 /* Previous buffer position.  */
   int prev_pos_byte;            /* Previous buffer position.  */
   int contin_hpos;              /* HPOS of last column of continued line.  */
@@ -1187,7 +1196,7 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
               /* Remember the previous value.  */
               prev_tab_offset = tab_offset;
 
-              if (wide_column)
+              if (wide_column_end_hpos > width)
                 {
                   hpos -= prev_hpos;
                   tab_offset += prev_hpos;
@@ -1223,7 +1232,7 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
            */
 
           if (contin_hpos && prev_hpos == 0
-              && contin_hpos < width && !wide_column)
+              && contin_hpos < width && !wide_column_end_hpos)
             {
               /* Line breaking occurs in the middle of multi-column
                  character.  Go back to previous line.  */
@@ -1240,7 +1249,8 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
       if (vpos > tovpos || vpos == tovpos && hpos >= tohpos)
         {
           if (contin_hpos && prev_hpos == 0
-              && ((hpos > tohpos && contin_hpos == width) || wide_column))
+              && ((hpos > tohpos && contin_hpos == width)
+                  || (wide_column_end_hpos > width)))
             { /* Line breaks because we can't put the character at the
                  previous line any more.  It is not the multi-column
                  character continued in middle.  Go back to previous
@@ -1260,7 +1270,7 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
       prev_hpos = hpos;
       prev_pos = pos;
       prev_pos_byte = pos_byte;
-      wide_column = 0;
+      wide_column_end_hpos = 0;
 
       /* Consult the width run cache to see if we can avoid inspecting
          the text character-by-character.  */
@@ -1348,8 +1358,9 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
                 }
             }
 
-          if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c))
-              && ! (multibyte && BASE_LEADING_CODE_P (c)))
+          if (dp != 0
+              && ! (multibyte && BASE_LEADING_CODE_P (c))
+              && VECTORP (DISP_CHAR_VECTOR (dp, c)))
             hpos += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
           else if (c >= 040 && c < 0177)
             hpos++;
@@ -1429,37 +1440,14 @@ compute_motion (from, fromvpos, fromhpos, did_motion, to, tovpos, tohpos, width,
             {
               /* Start of multi-byte form.  */
               unsigned char *ptr;
-              int len, actual_len;
-
-              pos--, pos_byte--;                /* rewind POS */
+              int bytes, width, wide_column;
 
+              pos_byte--;       /* rewind POS_BYTE */
               ptr = BYTE_POS_ADDR (pos_byte);
-              len = BUFFER_CEILING_OF (pos_byte) - pos_byte + 1;
-
-              c = STRING_CHAR_AND_LENGTH (ptr, len, actual_len);
-
-              if (dp != 0 && VECTORP (DISP_CHAR_VECTOR (dp, c)))
-                hpos += XVECTOR (DISP_CHAR_VECTOR (dp, c))->size;
-              else if (actual_len == 1)
-                hpos += 4;
-              else if (COMPOSITE_CHAR_P (c))
-                {
-                  int id = COMPOSITE_CHAR_ID (c);
-                  int width = (id < n_cmpchars) ? cmpchar_table[id]->width : 0;
-                  hpos += width;
-                  if (width > 1)
-                    wide_column = 1;
-                }
-              else
-                {
-                  int width = WIDTH_BY_CHAR_HEAD (*ptr);
-                  hpos += width;
-                  if (width > 1)
-                    wide_column = 1;
-                }
-
-              pos++;
-              pos_byte += actual_len;
+              MULTIBYTE_BYTES_WIDTH (ptr, c, dp);
+              pos_byte += bytes;
+              wide_column_end_hpos = hpos + wide_column;
+              hpos += width;
             }
           else
             hpos += (ctl_arrow && c < 0200) ? 2 : 4;