git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/file/GeneralRocketLoader.java

   1 package net.sf.openrocket.file;
   2
   3 import net.sf.openrocket.document.OpenRocketDocument;
   4 import net.sf.openrocket.file.openrocket.OpenRocketLoader;
   5
   6 import java.io.BufferedInputStream;
   7 import java.io.IOException;
   8 import java.io.InputStream;
   9 import java.nio.charset.Charset;
  10 import java.util.Arrays;
  11 import java.util.zip.GZIPInputStream;
  12
  13
  14 /**
  15  * A rocket loader that auto-detects the document type and uses the appropriate
  16  * loading.  Supports loading of GZIPed files as well with transparent
  17  * uncompression.
  18  *
  19  * @author Sampo Niskanen <sampo.niskanen@iki.fi>
  20  */
  21 public class GeneralRocketLoader extends RocketLoader {
  22
  23         private static final int READ_BYTES = 300;
  24
  25         private static final byte[] GZIP_SIGNATURE = { 31, -117 };  // 0x1f, 0x8b
  26         private static final byte[] OPENROCKET_SIGNATURE =
  27                 "<openrocket".getBytes(Charset.forName("US-ASCII"));
  28     private static final byte[] ROCKSIM_SIGNATURE =
  29         "<RockSimDoc".getBytes(Charset.forName("US-ASCII"));
  30
  31         private final OpenRocketLoader openRocketLoader = new OpenRocketLoader();
  32
  33     private final net.sf.openrocket.file.rocksim.importt.RocksimLoader rocksimLoader = new net.sf.openrocket.file.rocksim.importt.RocksimLoader();
  34
  35         @Override
  36         protected OpenRocketDocument loadFromStream(InputStream source) throws IOException,
  37                         RocketLoadException {
  38
  39                 // Check for mark() support
  40                 if (!source.markSupported()) {
  41                         source = new BufferedInputStream(source);
  42                 }
  43
  44                 // Read using mark()
  45                 byte[] buffer = new byte[READ_BYTES];
  46                 int count;
  47                 source.mark(READ_BYTES + 10);
  48                 count = source.read(buffer);
  49                 source.reset();
  50
  51                 if (count < 10) {
  52                         throw new RocketLoadException("Unsupported or corrupt file.");
  53                 }
  54
  55                 // Detect the appropriate loader
  56
  57                 // Check for GZIP
  58                 if (buffer[0] == GZIP_SIGNATURE[0]  &&  buffer[1] == GZIP_SIGNATURE[1]) {
  59                         OpenRocketDocument doc = loadFromStream(new GZIPInputStream(source));
  60                         doc.getDefaultStorageOptions().setCompressionEnabled(true);
  61                         return doc;
  62                 }
  63
  64                 // Check for OpenRocket
  65                 int match = 0;
  66                 for (int i=0; i < count; i++) {
  67                         if (buffer[i] == OPENROCKET_SIGNATURE[match]) {
  68                                 match++;
  69                                 if (match == OPENROCKET_SIGNATURE.length) {
  70                                         return loadUsing(source, openRocketLoader);
  71                                 }
  72                         } else {
  73                                 match = 0;
  74                         }
  75                 }
  76
  77         byte[] typeIdentifier = Arrays.copyOf(buffer, ROCKSIM_SIGNATURE.length);
  78         if (Arrays.equals(ROCKSIM_SIGNATURE, typeIdentifier)) {
  79             return loadUsing(source, rocksimLoader);
  80         }
  81                 throw new RocketLoadException("Unsupported or corrupt file.");
  82         }
  83
  84         private OpenRocketDocument loadUsing(InputStream source, RocketLoader loader)
  85         throws RocketLoadException {
  86                 warnings.clear();
  87                 OpenRocketDocument doc = loader.load(source);
  88                 warnings.addAll(loader.getWarnings());
  89                 return doc;
  90         }
  91 }