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

   1 package net.sf.openrocket.file;
   2
   3 import java.io.BufferedInputStream;
   4 import java.io.IOException;
   5 import java.io.InputStream;
   6 import java.nio.charset.Charset;
   7 import java.util.zip.GZIPInputStream;
   8 import java.util.Arrays;
   9
  10 import net.sf.openrocket.document.OpenRocketDocument;
  11 import net.sf.openrocket.file.openrocket.OpenRocketLoader;
  12 import net.sf.openrocket.file.rocksim.RocksimLoader;
  13
  14
  15 /**
  16  * A rocket loader that auto-detects the document type and uses the appropriate
  17  * loading.  Supports loading of GZIPed files as well with transparent
  18  * uncompression.
  19  *
  20  * @author Sampo Niskanen <sampo.niskanen@iki.fi>
  21  */
  22 public class GeneralRocketLoader extends RocketLoader {
  23
  24         private static final int READ_BYTES = 300;
  25
  26         private static final byte[] GZIP_SIGNATURE = { 31, -117 };  // 0x1f, 0x8b
  27         private static final byte[] OPENROCKET_SIGNATURE =
  28                 "<openrocket".getBytes(Charset.forName("US-ASCII"));
  29     private static final byte[] ROCKSIM_SIGNATURE =
  30         "<RockSimDoc".getBytes(Charset.forName("US-ASCII"));
  31
  32         private final OpenRocketLoader openRocketLoader = new OpenRocketLoader();
  33
  34     private final RocksimLoader rocksimLoader = new RocksimLoader();
  35
  36         @Override
  37         protected OpenRocketDocument loadFromStream(InputStream source) throws IOException,
  38                         RocketLoadException {
  39
  40                 // Check for mark() support
  41                 if (!source.markSupported()) {
  42                         source = new BufferedInputStream(source);
  43                 }
  44
  45                 // Read using mark()
  46                 byte[] buffer = new byte[READ_BYTES];
  47                 int count;
  48                 source.mark(READ_BYTES + 10);
  49                 count = source.read(buffer);
  50                 source.reset();
  51
  52                 if (count < 10) {
  53                         throw new RocketLoadException("Unsupported or corrupt file.");
  54                 }
  55
  56                 // Detect the appropriate loader
  57
  58                 // Check for GZIP
  59                 if (buffer[0] == GZIP_SIGNATURE[0]  &&  buffer[1] == GZIP_SIGNATURE[1]) {
  60                         OpenRocketDocument doc = loadFromStream(new GZIPInputStream(source));
  61                         doc.getDefaultStorageOptions().setCompressionEnabled(true);
  62                         return doc;
  63                 }
  64
  65                 // Check for OpenRocket
  66                 int match = 0;
  67                 for (int i=0; i < count; i++) {
  68                         if (buffer[i] == OPENROCKET_SIGNATURE[match]) {
  69                                 match++;
  70                                 if (match == OPENROCKET_SIGNATURE.length) {
  71                                         return loadUsing(source, openRocketLoader);
  72                                 }
  73                         } else {
  74                                 match = 0;
  75                         }
  76                 }
  77
  78         byte[] typeIdentifier = Arrays.copyOf(buffer, ROCKSIM_SIGNATURE.length);
  79         if (Arrays.equals(ROCKSIM_SIGNATURE, typeIdentifier)) {
  80             return loadUsing(source, rocksimLoader);
  81         }
  82                 throw new RocketLoadException("Unsupported or corrupt file.");
  83         }
  84
  85         private OpenRocketDocument loadUsing(InputStream source, RocketLoader loader)
  86         throws RocketLoadException {
  87                 warnings.clear();
  88                 OpenRocketDocument doc = loader.load(source);
  89                 warnings.addAll(loader.getWarnings());
  90                 return doc;
  91         }
  92 }