// Parses the entire contents of an XNB file.
void ContentReader::ReadXnb()
{
// Read the XNB header.
uint32_t endPosition = ReadHeader();
ReadTypeManifest();
uint32_t sharedResourceCount = Read7BitEncodedInt();
// Read the primary asset data.
Log.WriteLine("Asset:");
ReadObject();
// Read any shared resource instances.
for (uint32_t i = 0 ; i < sharedResourceCount; i++)
{
Log.WriteLine("Shared resource %d:", i);
ReadObject();
}
// Make sure we read the amount of data that the file header said we should.
if (FilePosition() != endPosition)
{
throw app_exception("End position does not match XNB header: unexpected amount of data was read.");
}
}
// Reads the manifest of what types are contained in this XNB file.
void ContentReader::ReadTypeManifest()
{
Log.WriteLine("Type readers:");
Log.Indent();
// How many type readers does this .xnb use?
uint32_t typeReaderCount = Read7BitEncodedInt();
typeReaders.clear();
for (uint32_t i = 0; i < typeReaderCount; i++)
{
// Read the type reader metadata.
wstring readerName = ReadString();
int32_t readerVersion = ReadInt32();
Log.WriteLine("%S (version %d)", readerName.c_str(), readerVersion);
// Look up and store this type reader implementation class.
TypeReader* reader = typeReaderManager->GetByReaderName(readerName);
typeReaders.push_back(reader);
}
// Initialize the readers in a separate pass after they are all registered, in case there are
// circular dependencies between them (eg. an array of classes which themselves contain arrays).
for (vector<TypeReader*>::iterator iter = typeReaders.begin(); iter != typeReaders.end(); iter++)
{
TypeReader* reader = *iter;
reader->Initialize(typeReaderManager);
}
Log.Unindent();
}
// Reads a shared resource ID, which indexes into the table of shared object instances that come after the primary asset.
void ContentReader::ReadSharedResource()
{
uint32_t resourceId = Read7BitEncodedInt();
if (resourceId)
{
Log.WriteLine("shared resource #%u", resourceId - 1);
}
else
{
Log.WriteLine("null");
}
}
// Reads the typeId from the start of a polymorphic object, and looks up the appropriate TypeReader implementation.
TypeReader* ContentReader::ReadTypeId()
{
uint32_t typeId = Read7BitEncodedInt();
if (typeId > 0)
{
// Look up the reader for this type of object.
typeId--;
if (typeId >= typeReaders.size())
{
throw app_exception("Invalid XNB file: typeId is out of range.");
}
return typeReaders[typeId];
}
else
{
// A zero typeId indicates a null object.
return NULL;
}
}
// public string ReadString() [instance] :351
uString* BinaryReader::ReadString()
{
return ::g::Uno::Runtime::Implementation::TextEncodingImpl::DecodeUtf8(ReadBytes(Read7BitEncodedInt()));
}
