convert method

@override List<List<String>> convert(String items)

Converts input and returns the result of the conversion.

Implementation

@override
List<List<String>> convert(String items) {
  final result = <List<String>>[[]];
  int leftIndex = 0;
  int rightIndex = 0;
  bool isInsideDoubleQuotes = false;
  while (rightIndex < items.length) {
    final current = items[rightIndex];
    if (isInsideDoubleQuotes) {
      if (current == '"') {
        if (rightIndex < items.length - 1 && items[rightIndex + 1] == '"') {
          rightIndex += 2;
        } else {
          isInsideDoubleQuotes = false;
          result.last.add(
            items.substring(leftIndex, rightIndex).replaceAll('""', '"'),
          );
          leftIndex = rightIndex = rightIndex + 1;
        }
      } else {
        rightIndex++;
      }
    } else {
      if (leftIndex == rightIndex && current == '"') {
        isInsideDoubleQuotes = true;
        leftIndex++;
        rightIndex++;
      } else if (current == ',') {
        if (leftIndex == rightIndex && items[rightIndex - 1] == '"') {
          leftIndex = rightIndex = rightIndex + 1;
        } else {
          result.last.add(items.substring(leftIndex, rightIndex));
          leftIndex = rightIndex = rightIndex + 1;
        }
      } else if (current == '\r') {
        if (rightIndex < items.length - 1 && items[rightIndex + 1] == '\n') {
          if (leftIndex != rightIndex || items[rightIndex - 1] == ',') {
            result.last.add(items.substring(leftIndex, rightIndex));
          }
          result.add([]);
          leftIndex = rightIndex = rightIndex + 2;
        } else {
          rightIndex++;
        }
      } else if (current == '\n') {
        if (leftIndex != rightIndex || items[rightIndex - 1] == ',') {
          result.last.add(items.substring(leftIndex, rightIndex));
        }
        result.add([]);
        leftIndex = rightIndex = rightIndex + 1;
      } else {
        rightIndex++;
      }
    }
  }
  if (items[leftIndex - 1] == ',' || leftIndex != rightIndex) {
    result.last.add(items.substring(leftIndex, rightIndex));
  }
  if (result.last.isEmpty) {
    result.removeLast();
  }
  return result;
}