Cleanup: move utf8 offset conversion into BLI_string_utf8

There isn't anything specific to text data with these functions.

2 files changed, 55 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_string_utf8.h b/source/blender/blenlib/BLI_string_utf8.h
index 70586b671b4..0cdd6e94610 100644
--- a/source/blender/blenlib/BLI_string_utf8.h
+++ b/source/blender/blenlib/BLI_string_utf8.h
@@ -89,6 +89,11 @@ size_t BLI_str_partition_ex_utf8(const char *str,
                                  const char **suf,
                                  const bool from_right) ATTR_NONNULL(1, 3, 4, 5);
 
+int BLI_str_utf8_offset_to_index(const char *str, int offset);
+int BLI_str_utf8_offset_from_index(const char *str, int index);
+int BLI_str_utf8_offset_to_column(const char *str, int offset);
+int BLI_str_utf8_offset_from_column(const char *str, int column);
+
 #define BLI_UTF8_MAX 6       /* mem */
 #define BLI_UTF8_WIDTH_MAX 2 /* columns */
 #define BLI_UTF8_ERR ((unsigned int)-1)
diff --git a/source/blender/blenlib/intern/string_utf8.c b/source/blender/blenlib/intern/string_utf8.c
index 01412416854..22c23727d76 100644
--- a/source/blender/blenlib/intern/string_utf8.c
+++ b/source/blender/blenlib/intern/string_utf8.c
@@ -868,3 +868,53 @@ size_t BLI_str_partition_ex_utf8(const char *str,
   *suf = *sep = NULL;
   return str_len;
 }
+
+/* -------------------------------------------------------------------- */
+/** \name Offset Conversion in Strings
+ * \{ */
+
+int BLI_str_utf8_offset_to_index(const char *str, int offset)
+{
+  int index = 0, pos = 0;
+  while (pos != offset) {
+    pos += BLI_str_utf8_size(str + pos);
+    index++;
+  }
+  return index;
+}
+
+int BLI_str_utf8_offset_from_index(const char *str, int index)
+{
+  int offset = 0, pos = 0;
+  while (pos != index) {
+    offset += BLI_str_utf8_size(str + offset);
+    pos++;
+  }
+  return offset;
+}
+
+int BLI_str_utf8_offset_to_column(const char *str, int offset)
+{
+  int column = 0, pos = 0;
+  while (pos < offset) {
+    column += BLI_str_utf8_char_width_safe(str + pos);
+    pos += BLI_str_utf8_size_safe(str + pos);
+  }
+  return column;
+}
+
+int BLI_str_utf8_offset_from_column(const char *str, int column)
+{
+  int offset = 0, pos = 0, col;
+  while (*(str + offset) && pos < column) {
+    col = BLI_str_utf8_char_width_safe(str + offset);
+    if (pos + col > column) {
+      break;
+    }
+    offset += BLI_str_utf8_size_safe(str + offset);
+    pos += col;
+  }
+  return offset;
+}
+
+/** \} */