SWFReader.java

/*
 * JSwiff is an open source Java API for Macromedia Flash file generation
 * and manipulation
 *
 * Copyright (C) 2004-2006 Ralf Terdic (contact@jswiff.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package com.jswiff;

import com.jswiff.io.InputBitStream;
import com.jswiff.listeners.SWFListener;
import com.jswiff.swfrecords.SWFHeader;
import com.jswiff.swfrecords.tags.MalformedTag;
import com.jswiff.swfrecords.tags.Tag;
import com.jswiff.swfrecords.tags.TagConstants;
import com.jswiff.swfrecords.tags.TagHeader;
import com.jswiff.swfrecords.tags.TagReaderImpl;

import java.io.InputStream;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;


/**
 * This class reads an SWF file from a stream, invoking registered listeners to
 * process the SWF. Use the following code to parse a SWF into a
 * <code>SWFDocument</code> instance:
 * <pre>
 * <code>
 * SWFReader reader            = new SWFReader(inputStream);
 * SWFDocumentReader docReader = new SWFDocumentReader();
 * reader.addListener(docReader);
 * reader.read();
 * SWFDocument doc             = docReader.getDocument();
 * </code>
 * </pre>
 */
public class SWFReader {
	protected InputBitStream bitStream;
  protected List listeners   = new ArrayList();
  protected boolean japanese;

  /**
   * Creates a new SWF reader which reads from the specified stream.
   *
   * @param stream the input stream the SWF file is read from
   */
  public SWFReader(InputStream stream) {
    this.bitStream = new InputBitStream(stream);
  }

  /**
   * Specifies whether strings should be decoded using Japanese encoding
   * (Shift-JIS). This is relevant only for SWF 5 or earlier, where strings
   * are encoded using either ANSI or Shift-JIS. In Flash Player, the decoding
   * choice is made depending on the locale, as this information is not stored
   * in the SWF. Later SWF versions use Unicode (UTF-8) and ignore this
   * option.
   *
   * @param japanese <code>true</code> if Shift-JIS encoding is to be used
   */
  public void setJapanese(boolean japanese) {
    this.japanese = japanese;
  }

  /**
   * Registers a listener in order to process the SWF content.
   *
   * @param listener a <code>SWFListener</code> instance
   */
  public void addListener(SWFListener listener) {
    listeners.add(listener);
  }

  /**
   * Reads the SWF content from the stream passed to the constructor, and
   * invokes the methods of the registered listeners. Finally, the stream is
   * closed.
   *
   * @see SWFListener
   */
  public void read() {
    preProcess();
    SWFHeader header;
    try {
      header = new SWFHeader(bitStream);
    } catch (Exception e) {
      // invoke error processing
      processHeaderReadError(e);
      return; // without header we cannot do anything...
    }
    processHeader(header);
    do {
      // we check this because of an OpenOffice export bug
      // (END tag written as a UI8 (00)instead of an UI16 (00 00))
      if ((header.getFileLength() - bitStream.getOffset()) < 2) {
        break;
      }
      TagHeader tagHeader = null;
      try {
        tagHeader = TagReaderImpl.getInstance().readTagHeader(bitStream);
      } catch (Exception e) {
        processTagHeaderReadError(e);
        break; // cannot continue without tag header
      }
      processTagHeader(tagHeader);
      Tag tag        = null;
      byte[] tagData = null;
      try {
        tagData   = TagReaderImpl.getInstance().readTagData(bitStream, tagHeader);
        tag       = TagReaderImpl.getInstance().readTag(
            tagHeader, tagData, header.getVersion(), japanese);
        if (tag.getCode() == TagConstants.END) {
          break;
        }
      } catch (Exception e) {
        // invoke error processing
        if (processTagReadError(tagHeader, tagData, e)) {
          break;
        }
        tag = new MalformedTag(tagHeader, tagData, e);
      }
      processTag(tag, bitStream.getOffset());
    } while (true);
    postProcess();
    try {
      bitStream.close();
    } catch (Exception e) {
      // empty on purpose - don't need to propagate errors which occur while closing
    }
  }

  protected void postProcess() {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).postProcess();
    }
  }

  protected void preProcess() {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).preProcess();
    }
  }

  protected void processHeader(SWFHeader header) {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).processHeader(header);
    }
  }

  protected void processHeaderReadError(Exception e) {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).processHeaderReadError(e);
    }
  }

  protected void processTag(Tag tag, long streamOffset) {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).processTag(tag, streamOffset);
    }
  }

  protected void processTagHeader(TagHeader tagHeader) {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).processTagHeader(tagHeader);
    }
  }

  protected void processTagHeaderReadError(Exception e) {
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      ((SWFListener) iterator.next()).processTagHeaderReadError(e);
    }
  }

  protected boolean processTagReadError(
    TagHeader tagHeader, byte[] tagData, Exception e) {
    boolean result = false;
    for (Iterator iterator = listeners.iterator(); iterator.hasNext();) {
      result = ((SWFListener) iterator.next()).processTagReadError(
          tagHeader, tagData, e) || result;
    }
    return result;
  }
}