/**
* Helper method that creates an array of bytes for the specified <tt>Set</tt> of <tt>URN</tt>
* instances. The bytes are written as specified in HUGE v 0.94.
*
* @param urns the <tt>Set</tt> of <tt>URN</tt> instances to use in constructing the byte array
*/
private static byte[] createExtBytes(Set urns, GGEPContainer ggep) {
try {
if (isEmpty(urns) && ggep.isEmpty()) return DataUtils.EMPTY_BYTE_ARRAY;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
if (!isEmpty(urns)) {
// Add the extension for URNs, if any.
Iterator iter = urns.iterator();
while (iter.hasNext()) {
URN urn = (URN) iter.next();
Assert.that(urn != null, "Null URN");
baos.write(urn.toString().getBytes());
// If there's another URN, add the separator.
if (iter.hasNext()) {
baos.write(EXT_SEPARATOR);
}
}
// If there's ggep data, write the separator.
if (!ggep.isEmpty()) baos.write(EXT_SEPARATOR);
}
// It is imperitive that GGEP is added LAST.
// That is because GGEP can contain 0x1c (EXT_SEPARATOR)
// within it, which would cause parsing problems
// otherwise.
if (!ggep.isEmpty()) GGEPUtil.addGGEP(baos, ggep);
return baos.toByteArray();
} catch (IOException impossible) {
ErrorService.error(impossible);
return DataUtils.EMPTY_BYTE_ARRAY;
}
}
/**
* Factory method for instantiating individual responses from an <tt>InputStream</tt> instance.
*
* @param is the <tt>InputStream</tt> to read from
* @throws <tt>IOException</tt> if there are any problems reading from or writing to the stream
*/
public static Response createFromStream(InputStream is) throws IOException {
// extract file index & size
long index = ByteOrder.uint2long(ByteOrder.leb2int(is));
long size = ByteOrder.uint2long(ByteOrder.leb2int(is));
if ((index & 0xFFFFFFFF00000000L) != 0) throw new IOException("invalid index: " + index);
// must use Integer.MAX_VALUE instead of mask because
// this value is later converted to an int, so we want
// to ensure that when it's converted it doesn't become
// negative.
if (size > Integer.MAX_VALUE || size < 0) throw new IOException("invalid size: " + size);
// The file name is terminated by a null terminator.
// A second null indicates the end of this response.
// Gnotella & others insert meta-information between
// these null characters. So we have to handle this.
// See http://gnutelladev.wego.com/go/
// wego.discussion.message?groupId=139406&
// view=message&curMsgId=319258&discId=140845&
// index=-1&action=view
// Extract the filename
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int c;
while ((c = is.read()) != 0) {
if (c == -1) throw new IOException("EOF before null termination");
baos.write(c);
}
String name = new String(baos.toByteArray(), "UTF-8");
if (name.length() == 0) {
throw new IOException("empty name in response");
}
// Extract extra info, if any
baos.reset();
while ((c = is.read()) != 0) {
if (c == -1) throw new IOException("EOF before null termination");
baos.write(c);
}
byte[] rawMeta = baos.toByteArray();
if (rawMeta == null || rawMeta.length == 0) {
if (is.available() < 16) {
throw new IOException("not enough room for the GUID");
}
return new Response(index, size, name);
} else {
// now handle between-the-nulls
// \u001c is the HUGE v0.93 GEM delimiter
HUGEExtension huge = new HUGEExtension(rawMeta);
Set urns = huge.getURNS();
LimeXMLDocument doc = null;
Iterator iter = huge.getMiscBlocks().iterator();
while (iter.hasNext() && doc == null) doc = createXmlDocument(name, (String) iter.next());
GGEPContainer ggep = GGEPUtil.getGGEP(huge.getGGEP());
return new Response(index, size, name, urns, doc, ggep, rawMeta);
}
}
