Function stringToUTF8Array

sqlite-wasm-opfs/jswasm/sqlite3.js:415–453

(str, heap, outIdx, maxBytesToWrite)

function stringToUTF8Array(str, heap, outIdx, maxBytesToWrite) {
  if (!(maxBytesToWrite > 0)) 
    return 0;

  var startIdx = outIdx;
  var endIdx = outIdx + maxBytesToWrite - 1; 
  for (var i = 0; i < str.length; ++i) {
    
    
    
    var u = str.charCodeAt(i); 
    if (u >= 0xD800 && u <= 0xDFFF) {
      var u1 = str.charCodeAt(++i);
      u = 0x10000 + ((u & 0x3FF) << 10) | (u1 & 0x3FF);
    }
    if (u <= 0x7F) {
      if (outIdx >= endIdx) break;
      heap[outIdx++] = u;
    } else if (u <= 0x7FF) {
      if (outIdx + 1 >= endIdx) break;
      heap[outIdx++] = 0xC0 | (u >> 6);
      heap[outIdx++] = 0x80 | (u & 63);
    } else if (u <= 0xFFFF) {
      if (outIdx + 2 >= endIdx) break;
      heap[outIdx++] = 0xE0 | (u >> 12);
      heap[outIdx++] = 0x80 | ((u >> 6) & 63);
      heap[outIdx++] = 0x80 | (u & 63);
    } else {
      if (outIdx + 3 >= endIdx) break;
      heap[outIdx++] = 0xF0 | (u >> 18);
      heap[outIdx++] = 0x80 | ((u >> 12) & 63);
      heap[outIdx++] = 0x80 | ((u >> 6) & 63);
      heap[outIdx++] = 0x80 | (u & 63);
    }
  }
  
  heap[outIdx] = 0;
  return outIdx - startIdx;
}