serializeDirectedParamList function

Uint8List serializeDirectedParamList(List<int> directions, List<ParamValue> params)

Serializes directed parameters as DRT1 (magic + count + direction + ParamValue payload per entry) using the same two-pass writer as serializeParams.

Implementation

Uint8List serializeDirectedParamList(
  List<int> directions,
  List<ParamValue> params,
) {
  if (directions.length != params.length) {
    throw ArgumentError(
      'directions.length (${directions.length}) != params.length '
      '(${params.length})',
    );
  }
  if (params.isEmpty) {
    final empty = Uint8List(8);
    empty[0] = 0x44; // D
    empty[1] = 0x52; // R
    empty[2] = 0x54; // T
    empty[3] = 0x31; // 1
    // count = 0 already
    return empty;
  }

  var totalBytes = 8; // magic(4) + count(4)
  final encodedText = List<List<int>?>.filled(params.length, null);
  for (var i = 0; i < params.length; i++) {
    totalBytes += 1; // direction
    switch (params[i]) {
      case ParamValueNull():
        totalBytes += 5;
      case ParamValueString(:final value):
        if (_isAsciiOnly(value)) {
          totalBytes += 5 + value.length;
        } else {
          final b = utf8.encode(value);
          encodedText[i] = b;
          totalBytes += 5 + b.length;
        }
      case ParamValueInt32():
        totalBytes += 9;
      case ParamValueInt64():
        totalBytes += 13;
      case ParamValueDecimal(:final value):
        if (_isAsciiOnly(value)) {
          totalBytes += 5 + value.length;
        } else {
          final b = utf8.encode(value);
          encodedText[i] = b;
          totalBytes += 5 + b.length;
        }
      case ParamValueBinary(:final value):
        totalBytes += 5 + value.length;
      case ParamValueRefCursorOut():
        totalBytes += 5;
    }
  }

  final out = Uint8List(totalBytes);
  final bd = ByteData.sublistView(out);
  out[0] = 0x44;
  out[1] = 0x52;
  out[2] = 0x54;
  out[3] = 0x31;
  bd.setUint32(4, params.length, _littleEndian);
  var off = 8;
  for (var i = 0; i < params.length; i++) {
    out[off++] = directions[i];
    switch (params[i]) {
      case ParamValueNull():
        out[off] = _tagNull;
        bd.setUint32(off + 1, 0, _littleEndian);
        off += 5;
      case ParamValueString(:final value):
        final encoded = encodedText[i];
        if (encoded != null) {
          out[off] = _tagString;
          bd.setUint32(off + 1, encoded.length, _littleEndian);
          out.setRange(off + 5, off + 5 + encoded.length, encoded);
          off += 5 + encoded.length;
        } else {
          out[off] = _tagString;
          bd.setUint32(off + 1, value.length, _littleEndian);
          _writeAsciiString(out, off + 5, value);
          off += 5 + value.length;
        }
      case ParamValueInt32(:final value):
        out[off] = _tagInteger;
        bd.setUint32(off + 1, 4, _littleEndian);
        bd.setInt32(off + 5, value, _littleEndian);
        off += 9;
      case ParamValueInt64(:final value):
        out[off] = _tagBigInt;
        bd.setUint32(off + 1, 8, _littleEndian);
        bd.setInt64(off + 5, value, _littleEndian);
        off += 13;
      case ParamValueDecimal(:final value):
        final encoded = encodedText[i];
        if (encoded != null) {
          out[off] = _tagDecimal;
          bd.setUint32(off + 1, encoded.length, _littleEndian);
          out.setRange(off + 5, off + 5 + encoded.length, encoded);
          off += 5 + encoded.length;
        } else {
          out[off] = _tagDecimal;
          bd.setUint32(off + 1, value.length, _littleEndian);
          _writeAsciiString(out, off + 5, value);
          off += 5 + value.length;
        }
      case ParamValueBinary(:final value):
        final vLen = value.length;
        out[off] = _tagBinary;
        bd.setUint32(off + 1, vLen, _littleEndian);
        out.setRange(off + 5, off + 5 + vLen, value);
        off += 5 + vLen;
      case ParamValueRefCursorOut():
        out[off] = _tagRefCursorOut;
        bd.setUint32(off + 1, 0, _littleEndian);
        off += 5;
    }
  }
  return out;
}