Function insert_utf8_char

src/base/string.cpp:104–141

Based on Allegro Unicode code (allegro/src/unicode.c)

// Based on Allegro Unicode code (allegro/src/unicode.c)
static std::size_t insert_utf8_char(std::string* result, wchar_t chr)
{
  int size, bits, b, i;

  if (chr < 128) {
    if (result)
      result->push_back(chr);
    return 1;
  }

  bits = 7;
  while (chr >= (1<<bits))
    bits++;

  size = 2;
  b = 11;

  while (b < bits) {
    size++;
    b += 5;
  }

  if (result) {
    b -= (7-size);
    int firstbyte = chr>>b;
    for (i=0; i<size; i++)
      firstbyte |= (0x80>>i);

    result->push_back(firstbyte);

    for (i=1; i<size; i++) {
      b -= 6;
      result->push_back(0x80 | ((chr>>b)&0x3F));
    }
  }

  return size;
}

std::string to_utf8(const std::wstring& src)
{