/*
 * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

part of pdf;

class PdfObjectStream extends PdfObject {
  /// This holds the stream's content.
  final PdfStream buf = PdfStream();

  /// defines if the stream needs to be converted to ascii85
  final bool isBinary;

  /// Constructs a stream. The supplied type is stored in the stream's header
  /// and is used by other objects that extend the [PdfStream] class (like
  /// [PdfImage]).
  /// By default, the stream will be compressed.
  ///
  /// @param type type for the stream
  /// @see [PdfImage]
  PdfObjectStream(PdfDocument pdfDocument, {String type, this.isBinary = false})
      : super(pdfDocument, type);

  List<int> _data;

  @override
  void _prepare() {
    super._prepare();

    if (params.containsKey("/Filter")) {
      // The data is already in the right format
      _data = buf.output();
    } else if (pdfDocument.deflate != null) {
      _data = pdfDocument.deflate(buf.output());
      params["/Filter"] = PdfStream.string("/FlateDecode");
    } else if (isBinary) {
      // This is a Ascii85 stream
      var e = Ascii85Encoder();
      _data = e.convert(buf.output());
      params["/Filter"] = PdfStream.string("/ASCII85Decode");
    } else {
      // This is a non-deflated stream
      _data = buf.output();
    }
    params["/Length"] = PdfStream.intNum(_data.length);
  }

  @override
  void _writeContent(PdfStream os) {
    super._writeContent(os);

    os.putString("stream\n");
    os.putBytes(_data);
    os.putString("\nendstream\n");
  }
}