Function ConvertUtf16ToModifiedUtf8

Bcore/src/main/cpp/dex/utf.cc:125–176

}

void ConvertUtf16ToModifiedUtf8(char* utf8_out, size_t byte_count,
                                const uint16_t* utf16_in, size_t char_count) {
  if (LIKELY(byte_count == char_count)) {
    // Common case where all characters are ASCII.
    const uint16_t *utf16_end = utf16_in + char_count;
    for (const uint16_t *p = utf16_in; p < utf16_end;) {
      *utf8_out++ = dchecked_integral_cast<char>(*p++);
    }
    return;
  }

  // String contains non-ASCII characters.
  while (char_count--) {
    const uint16_t ch = *utf16_in++;
    if (ch > 0 && ch <= 0x7f) {
      *utf8_out++ = ch;
    } else {
      // Char_count == 0 here implies we've encountered an unpaired
      // surrogate and we have no choice but to encode it as 3-byte UTF
      // sequence. Note that unpaired surrogates can occur as a part of
      // "normal" operation.
      if ((ch >= 0xd800 && ch <= 0xdbff) && (char_count > 0)) {
        const uint16_t ch2 = *utf16_in;

        // Check if the other half of the pair is within the expected
        // range. If it isn't, we will have to emit both "halves" as
        // separate 3 byte sequences.
        if (ch2 >= 0xdc00 && ch2 <= 0xdfff) {
          utf16_in++;
          char_count--;
          const uint32_t code_point = (ch << 10) + ch2 - 0x035fdc00;
          *utf8_out++ = (code_point >> 18) | 0xf0;
          *utf8_out++ = ((code_point >> 12) & 0x3f) | 0x80;
          *utf8_out++ = ((code_point >> 6) & 0x3f) | 0x80;
          *utf8_out++ = (code_point & 0x3f) | 0x80;
          continue;
        }
      }

      if (ch > 0x07ff) {
        // Three byte encoding.
        *utf8_out++ = (ch >> 12) | 0xe0;
        *utf8_out++ = ((ch >> 6) & 0x3f) | 0x80;
        *utf8_out++ = (ch & 0x3f) | 0x80;
      } else /*(ch > 0x7f || ch == 0)*/ {
        // Two byte encoding.
        *utf8_out++ = (ch >> 6) | 0xc0;
        *utf8_out++ = (ch & 0x3f) | 0x80;
      }
    }
  }
}

int32_t ComputeUtf16HashFromModifiedUtf8(const char* utf8, size_t utf16_length) {
  uint32_t hash = 0;