scrolling text scrolling, unicode-aware strlen

wled00/src/font/codepages.h

@@ -16,6 +16,9 @@ uint16_t unicodeToWchar16(const unsigned char* utf8, size_t maxLen);           /
 // return nullptr at end of input
 const unsigned char* nextUnicode(const unsigned char* utf8, size_t maxLen);    // unicodetool.cpp
 
+// unicode-aware string length
+size_t strlenUC(const unsigned char* utf8);
+
 // translates unicode 2-byte (UTF-16) "code point" into corresponding character in codepage 437 (IBM PC aka PC-8)
 uint16_t wchar16ToCodepage437(uint16_t wideChar);                              // codepage437.cpp
 

wled00/src/font/unicodetool.cpp

@@ -72,4 +72,15 @@ const unsigned char* nextUnicode(const unsigned char* utf8, size_t maxLen) {
   else return utf8 + codeLength;                               // success: advance stream
 }
 
+// unicode-aware string length
+size_t strlenUC(const unsigned char* utf8) {
+  if ((utf8 == nullptr) || (utf8[0] == '\0')) return 0;
+  size_t maxLen = strlen((const char *)utf8);
+  size_t letters = 0;
+  for(const unsigned char* now = utf8; now != nullptr && now[0] != '\0'; now = nextUnicode(now, maxLen)) // iterates over utf-8 and count letters
+    letters++;
+
+  return letters;
+}
+
 #endif