BLI_string_utf8: simplify utf8 stepping logic

There were multiple utf8 functions which treated
errors slightly differently.

Split BLI_str_utf8_as_unicode_step into two functions.

- BLI_str_utf8_as_unicode_step_or_error returns error value
  when decoding fails and doesn't step.

- BLI_str_utf8_as_unicode_step always steps forward at least one
  returning the byte value without decoding
  (needed to display some latin1 file-paths).

Font drawing uses BLI_str_utf8_as_unicode_step and no longer
check for error values.

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_string_utf8.h b/source/blender/blenlib/BLI_string_utf8.h
index b936e39731d..1b12147fe0f 100644
--- a/source/blender/blenlib/BLI_string_utf8.h
+++ b/source/blender/blenlib/BLI_string_utf8.h
@@ -46,6 +46,9 @@ unsigned int BLI_str_utf8_as_unicode_and_size_safe(const char *__restrict p,
 unsigned int BLI_str_utf8_as_unicode_step(const char *__restrict p,
                                           size_t p_len,
                                           size_t *__restrict index) ATTR_NONNULL(1, 3);
+unsigned int BLI_str_utf8_as_unicode_step_or_error(const char *__restrict p,
+                                                   size_t p_len,
+                                                   size_t *__restrict index) ATTR_NONNULL(1, 3);
 
 size_t BLI_str_utf8_from_unicode(unsigned int c, char *outbuf);
 size_t BLI_str_utf8_as_utf32(char32_t *__restrict dst_w,