// The Vorbis header is in three packets; the initial small packet in
// the first page that identifies basic parameters, a second packet
// with bitstream comments and a third packet that holds the
// codebook.
public int synthesis_headerin(Comment vc, Packet op)
{
csBuffer opb=new csBuffer();
if(op!=null) {
opb.readinit(op.packet_base, op.packet, op.bytes);
// Which of the three types of header is this?
// Also verify header-ness, vorbis
{
byte[] buffer=new byte[6];
int packtype=opb.read(8);
//memset(buffer,0,6);
opb.read(buffer,6);
if(buffer[0]!='v' || buffer[1]!='o' || buffer[2]!='r' ||
buffer[3]!='b' || buffer[4]!='i' || buffer[5]!='s') {
// not a vorbis header
return(-1);
}
switch(packtype) {
case 0x01: // least significant *bit* is read first
if(op.b_o_s==0) {
// Not the initial packet
return(-1);
}
if(rate!=0) {
// previously initialized info header
return(-1);
}
return(unpack_info(opb));
case 0x03: // least significant *bit* is read first
if(rate==0) {
// um... we didn't get the initial header
return(-1);
}
return(vc.unpack(opb));
case 0x05: // least significant *bit* is read first
if(rate==0 || vc.vendor==null) {
// um... we didn;t get the initial header or comments yet
return(-1);
}
return(unpack_books(opb));
default:
// Not a valid vorbis header type
//return(-1);
break;
}
}
}
return(-1);
}
// uses the local ogg_stream storage in vf; this is important for
// non-streaming input sources
int fetch_headers(Info vi, Comment vc, int[] serialno, Page og_ptr)
{
//System.err.println("fetch_headers");
Page og=new Page();
Packet op=new Packet();
int ret;
if(og_ptr==null) {
ret=get_next_page(og, CHUNKSIZE);
if(ret==OV_EREAD) { return OV_EREAD; }
if(ret<0) { return OV_ENOTVORBIS; }
og_ptr=og;
}
if(serialno!=null) { serialno[0]=og_ptr.serialno(); }
os.init(og_ptr.serialno());
// extract the initial header from the first page and verify that the
// Ogg bitstream is in fact Vorbis data
vi.init();
vc.init();
int i=0;
while(i<3) {
os.pagein(og_ptr);
while(i<3) {
int result=os.packetout(op);
if(result==0) { break; }
if(result==-1) {
Console.Error.WriteLine("Corrupt header in logical bitstream.");
//goto bail_header;
vi.clear();
vc.clear();
os.clear();
return -1;
}
if(vi.synthesis_headerin(vc, op)!=0) {
Console.Error.WriteLine("Illegal header in logical bitstream.");
//goto bail_header;
vi.clear();
vc.clear();
os.clear();
return -1;
}
i++;
}
if(i<3)
if(get_next_page(og_ptr, 1)<0) {
Console.Error.WriteLine("Missing header in logical bitstream.");
//goto bail_header;
vi.clear();
vc.clear();
os.clear();
return -1;
}
}
return 0;
}
int open_seekable()
{
Info initial_i=new Info();
Comment initial_c=new Comment();
int serialno;
long end;
int ret;
int dataoffset;
Page og=new Page();
// is this even vorbis...?
int[] foo=new int[1];
ret=fetch_headers(initial_i, initial_c, foo, null);
serialno=foo[0];
dataoffset=(int)offset; //!!
os.clear();
if(ret==-1) { return(-1); }
// we can seek, so set out learning all about this file
skable=true;
//(callbacks.seek_func)(datasource, 0, SEEK_END);
fseek(datasource, 0, SEEK_END);
//offset=end=(callbacks.tell_func)(datasource);
offset=ftell(datasource);
end=offset;
// We get the offset for the last page of the physical bitstream.
// Most OggVorbis files will contain a single logical bitstream
end=get_prev_page(og);
// moer than one logical bitstream?
if(og.serialno()!=serialno) {
// Chained bitstream. Bisect-search each logical bitstream
// section. Do so based on serial number only
if(bisect_forward_serialno(0,0,end+1,serialno,0)<0) {
clear();
return OV_EREAD;
}
}
else {
// Only one logical bitstream
if(bisect_forward_serialno(0,end,end+1,serialno,0)<0) {
clear();
return OV_EREAD;
}
}
prefetch_all_headers(initial_i, initial_c, dataoffset);
return(raw_seek(0));
}
// last step of the OggVorbis_File initialization; get all the
// vorbis_info structs and PCM positions. Only called by the seekable
// initialization (local stream storage is hacked slightly; pay
// attention to how that's done)
void prefetch_all_headers(Info first_i,Comment first_c, int dataoffset)
{
Page og=new Page();
int ret;
vi=new Info[links];
vc=new Comment[links];
dataoffsets=new long[links];
pcmlengths=new long[links];
serialnos=new int[links];
for(int i=0; i<links; i++) {
if(first_i!=null && first_c!=null && i==0) {
// we already grabbed the initial header earlier. This just
// saves the waste of grabbing it again
// !!!!!!!!!!!!!
vi[i]=first_i;
//memcpy(vf->vi+i,first_i,sizeof(vorbis_info));
vc[i]=first_c;
//memcpy(vf->vc+i,first_c,sizeof(vorbis_comment));
dataoffsets[i]=dataoffset;
}
else {
// seek to the location of the initial header
seek_helper(offsets[i]); //!!!
if(fetch_headers(vi[i], vc[i], null, null)==-1) {
Console.Error.WriteLine("Error opening logical bitstream #"+(i+1)+"\n");
dataoffsets[i]=-1;
}
else {
dataoffsets[i]=offset;
os.clear();
}
}
// get the serial number and PCM length of this link. To do this,
// get the last page of the stream
long end=offsets[i+1]; //!!!
seek_helper(end);
while(true) {
ret=get_prev_page(og);
if(ret==-1) {
// this should not be possible
Console.Error.WriteLine("Could not find last page of logical "+
"bitstream #"+(i)+"\n");
vi[i].clear();
vc[i].clear();
break;
}
if(og.granulepos()!=-1) {
serialnos[i]=og.serialno();
pcmlengths[i]=og.granulepos();
break;
}
}
}
}
int open_nonseekable()
{
//System.err.println("open_nonseekable");
// we cannot seek. Set up a 'single' (current) logical bitstream entry
links=1;
vi=new Info[links];
vi[0]=new Info(); // ??
vc=new Comment[links];
vc[0]=new Comment(); // ?? bug?
// Try to fetch the headers, maintaining all the storage
int[]foo=new int[1];
if(fetch_headers(vi[0], vc[0], foo, null)==-1) { return(-1); }
current_serialno=foo[0];
make_decode_ready();
return 0;
}
