Function lengthBytesUTF8

js/sql-debug.js:870–892

(str)

// Returns the number of bytes the given Javascript string takes if encoded as a UTF8 byte array, EXCLUDING the null terminator byte.

function lengthBytesUTF8(str) {
  var len = 0;
  for (var i = 0; i < str.length; ++i) {
    // Gotcha: charCodeAt returns a 16-bit word that is a UTF-16 encoded code unit, not a Unicode code point of the character! So decode UTF16->UTF32->UTF8.
    // See http://unicode.org/faq/utf_bom.html#utf16-3
    var u = str.charCodeAt(i); // possibly a lead surrogate
    if (u >= 0xD800 && u <= 0xDFFF) u = 0x10000 + ((u & 0x3FF) << 10) | (str.charCodeAt(++i) & 0x3FF);
    if (u <= 0x7F) {
      ++len;
    } else if (u <= 0x7FF) {
      len += 2;
    } else if (u <= 0xFFFF) {
      len += 3;
    } else if (u <= 0x1FFFFF) {
      len += 4;
    } else if (u <= 0x3FFFFFF) {
      len += 5;
    } else {
      len += 6;
    }
  }
  return len;
}


// Given a pointer 'ptr' to a null-terminated UTF16LE-encoded string in the emscripten HEAP, returns