byteLength function

@DynamicTypeArgument('value', 'String | Buffer | Uint8List') int byteLength(dynamic value, [ String encoding = 'utf8', bool mustMatch = true ])

Implementation

@DynamicTypeArgument('value', 'String | Buffer | Uint8List')
int byteLength(dynamic value,
    [String encoding = 'utf8', bool mustMatch = true]) {
  if (value is Uint8List) {
    return value.lengthInBytes;
  } else if (value is Buffer) {
    return value._buf.lengthInBytes;
  } else if (value is String) {
    final len = value.length;
    if (!mustMatch && len == 0) return 0;

    // Use a for loop to avoid recursion
    bool loweredCase = false;
    for (;;) {
      switch (encoding) {
        case 'ascii':
        case 'latin1':
        case 'binary':
          return len;
        case 'utf8':
        case 'utf-8':
          return utf8ToBytes(value).length;
        case 'ucs2':
        case 'ucs-2':
        case 'utf16le':
        case 'utf-16le':
          return len * 2;
        case 'hex':
          return len >>> 1;
        case 'base64':
          return base64ToBytes(value).length;
        default:
          if (loweredCase) {
            return mustMatch ? -1 : utf8ToBytes(value).length; // assume utf8
          }
          encoding = (encoding).toLowerCase();
          loweredCase = true;
      }
    }
  } else {
    throw InvalidTypeError(
        'The "value" argument must be one of type String, Buffer, or Uint8List. '
        'Received type ${value.runtimeTypes}');
  }
}