Method utf8ascii

Code/Arduino_libraries/SSD1306/OLEDDisplay.cpp:1108–1133

You need to free the char!

// You need to free the char!
char* OLEDDisplay::utf8ascii(const String &str) {
  uint16_t k = 0;
  uint16_t length = str.length() + 1;

  // Copy the string into a char array
  char* s = (char*) malloc(length * sizeof(char));
  if(!s) {
    DEBUG_OLEDDISPLAY("[OLEDDISPLAY][utf8ascii] Can't allocate another char array. Drop support for UTF-8.\n");
    return (char*) str.c_str();
  }
  str.toCharArray(s, length);

  length--;

  for (uint16_t i=0; i < length; i++) {
    char c = (this->fontTableLookupFunction)(s[i]);
    if (c!=0) {
      s[k++]=c;
    }
  }

  s[k]=0;

  // This will leak 's' be sure to free it in the calling function.
  return s;
}

void OLEDDisplay::setFontTableLookupFunction(FontTableLookupFunction function) {
  this->fontTableLookupFunction = function;