private ContinuationSystemUseEntry Parse(IsoContext context, byte[] data, int offset)
{
ContinuationSystemUseEntry contEntry = null;
SuspExtension extension = null;
if (context.SuspExtensions != null && context.SuspExtensions.Count > 0)
{
extension = context.SuspExtensions[0];
}
int pos = offset;
while (data.Length - pos > 4)
{
byte len;
SystemUseEntry entry = SystemUseEntry.Parse(data, pos, context.VolumeDescriptor.CharacterEncoding,
extension, out len);
pos += len;
if (entry == null)
{
// A null entry indicates SUSP parsing must terminate.
// This will occur if a termination record is found,
// or if there is a problem with the SUSP data.
return(contEntry);
}
switch (entry.Name)
{
case "CE":
contEntry = (ContinuationSystemUseEntry)entry;
break;
case "ES":
ExtensionSelectSystemUseEntry esEntry = (ExtensionSelectSystemUseEntry)entry;
extension = context.SuspExtensions[esEntry.SelectedExtension];
break;
case "PD":
break;
case "SP":
case "ER":
StoreEntry(null, entry);
break;
default:
StoreEntry(extension, entry);
break;
}
}
return(contEntry);
}
private void StoreEntry(SuspExtension extension, SystemUseEntry entry)
{
string extensionId = extension == null ? string.Empty : extension.Identifier;
Dictionary <string, List <SystemUseEntry> > extensionEntries;
if (!_records.TryGetValue(extensionId, out extensionEntries))
{
extensionEntries = new Dictionary <string, List <SystemUseEntry> >();
_records.Add(extensionId, extensionEntries);
}
List <SystemUseEntry> entries;
if (!extensionEntries.TryGetValue(entry.Name, out entries))
{
entries = new List <SystemUseEntry>();
extensionEntries.Add(entry.Name, entries);
}
entries.Add(entry);
}
public static SystemUseEntry Parse(byte[] data, int offset, Encoding encoding, SuspExtension extension,
out byte length)
{
if (data[offset] == 0)
{
// A zero-byte here is invalid and indicates an incorrectly written SUSP field.
// Return null to indicate to the caller that SUSP parsing is terminated.
length = 0;
return(null);
}
string name = EndianUtilities.BytesToString(data, offset, 2);
length = data[offset + 2];
byte version = data[offset + 3];
switch (name)
{
case "CE":
return(new ContinuationSystemUseEntry(name, length, version, data, offset));
case "PD":
return(new PaddingSystemUseEntry(name, length, version));
case "SP":
return(new SharingProtocolSystemUseEntry(name, length, version, data, offset));
case "ST":
// Termination entry. There's no point in storing or validating this one.
// Return null to indicate to the caller that SUSP parsing is terminated.
return(null);
case "ER":
return(new ExtensionSystemUseEntry(name, length, version, data, offset, encoding));
case "ES":
return(new ExtensionSelectSystemUseEntry(name, length, version, data, offset));
case "AA":
case "AB":
case "AS":
// Placeholder support for Apple and Amiga extension records.
return(new GenericSystemUseEntry(name, length, version, data, offset));
default:
if (extension == null)
{
return(new GenericSystemUseEntry(name, length, version, data, offset));
}
return(extension.Parse(name, length, version, data, offset, encoding));
}
}