perf: reuse fast character size calculation algorithm from getvcol()

1 files changed, 11 insertions, 10 deletions

diff --git a/src/nvim/cursor.c b/src/nvim/cursor.c
index d8a63c1d7b..6c0a81838f 100644
--- a/src/nvim/cursor.c
+++ b/src/nvim/cursor.c
@@ -141,17 +141,18 @@ static int coladvance2(pos_T *pos, bool addspaces, bool finetune, colnr_T wcol_a
       }
     }
 
-    chartabsize_T cts;
-    init_chartabsize_arg(&cts, curwin, pos->lnum, 0, line, line);
-    while (cts.cts_vcol <= wcol && *cts.cts_ptr != NUL) {
-      // Count a tab for what it's worth (if list mode not on)
-      csize = win_lbr_chartabsize(&cts, &head);
-      MB_PTR_ADV(cts.cts_ptr);
-      cts.cts_vcol += csize;
+    CharsizeArg arg;
+    CSType cstype = init_charsize_arg(&arg, curwin, pos->lnum, line);
+    StrCharInfo ci = utf_ptr2StrCharInfo(line);
+    col = 0;
+    while (col <= wcol && *ci.ptr != NUL) {
+      CharSize cs = win_charsize(cstype, col, ci.ptr, ci.chr.value, &arg);
+      csize = cs.width;
+      head = cs.head;
+      col += cs.width;
+      ci = utfc_next(ci);
     }
-    col = cts.cts_vcol;
-    idx = (int)(cts.cts_ptr - line);
-    clear_chartabsize_arg(&cts);
+    idx = (int)(ci.ptr - line);
 
     // Handle all the special cases.  The virtual_active() check
     // is needed to ensure that a virtual position off the end of