BLI_string: add BLI_wcwidth_safe to avoid handling error values inline

source/blender/blenfont/intern/blf_font.cc

@@ -462,7 +462,7 @@ void blf_font_draw(FontBLF *font, const char *str, const size_t str_len, ResultB
 int blf_font_draw_mono(FontBLF *font, const char *str, const size_t str_len, int cwidth)
 {
   GlyphBLF *g;
-  int col, columns = 0;
+  int columns = 0;
   ft_pix pen_x = 0, pen_y = 0;
   ft_pix cwidth_fpx = ft_pix_from_int(cwidth);
 
@@ -481,11 +481,7 @@ int blf_font_draw_mono(FontBLF *font, const char *str, const size_t str_len, int
     /* do not return this loop if clipped, we want every character tested */
     blf_glyph_draw(font, gc, g, ft_pix_to_int_floor(pen_x), ft_pix_to_int_floor(pen_y));
 
-    col = BLI_wcwidth(char32_t(g->c));
-    if (col < 0) {
-      col = 1;
-    }
-
+    const int col = BLI_wcwidth_safe(char32_t(g->c));
     columns += col;
     pen_x += cwidth_fpx * col;
   }

source/blender/blenlib/BLI_string_utf8.h

@@ -174,6 +174,7 @@ size_t BLI_strncpy_wchar_from_utf8(wchar_t *__restrict dst_w,
  * Count columns that character/string occupies (based on `wcwidth.co`).
  */
 int BLI_wcwidth(char32_t ucs) ATTR_WARN_UNUSED_RESULT;
+int BLI_wcwidth_safe(char32_t ucs) ATTR_WARN_UNUSED_RESULT;
 int BLI_wcswidth(const char32_t *pwcs, size_t n) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL(1);
 
 /**

source/blender/blenlib/intern/string_utf8.c

@@ -460,6 +460,15 @@ int BLI_wcwidth(char32_t ucs)
   return mk_wcwidth(ucs);
 }
 
+int BLI_wcwidth_safe(char32_t ucs)
+{
+  const int columns = BLI_wcwidth(ucs);
+  if (columns >= 0) {
+    return columns;
+  }
+  return 1;
+}
+
 int BLI_wcswidth(const char32_t *pwcs, size_t n)
 {
   return mk_wcswidth(pwcs, n);
@@ -477,16 +486,12 @@ int BLI_str_utf8_char_width(const char *p)
 
 int BLI_str_utf8_char_width_safe(const char *p)
 {
-  int columns;
-
   uint unicode = BLI_str_utf8_as_unicode(p);
   if (unicode == BLI_UTF8_ERR) {
     return 1;
   }
 
-  columns = BLI_wcwidth((char32_t)unicode);
-
-  return (columns < 0) ? 1 : columns;
+  return BLI_wcwidth_safe((char32_t)unicode);
 }
 
 /* -------------------------------------------------------------------- */